Journal articles on the topic 'MRI sequence parameters'
To see the other types of publications on this topic, follow the link: MRI sequence parameters.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'MRI sequence parameters.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Jarraya, Mohamed, Rafael Heiss, Jeffrey Duryea, Armin M. Nagel, John A. Lynch, Ali Guermazi, Marc-André Weber, et al. "Bone Structure Analysis of the Radius Using Ultrahigh Field (7T) MRI: Relevance of Technical Parameters and Comparison with 3T MRI and Radiography." Diagnostics 11, no. 1 (January 12, 2021): 110. http://dx.doi.org/10.3390/diagnostics11010110.
Full textAbstract:
Bone fractal signature analysis (FSA—also termed bone texture analysis) is a tool that assesses structural changes that may relate to clinical outcomes and functions. Our aim was to compare bone texture analysis of the distal radius in patients and volunteers using radiography and 3T and 7T magnetic resonance imaging (MRI)—a patient group (n = 25) and a volunteer group (n = 25) were included. Participants in the patient group had a history of chronic wrist pain with suspected or confirmed osteoarthritis and/or ligament instability. All participants had 3T and 7T MRI including T1-weighted turbo spin echo (TSE) sequences. The 7T MRI examination included an additional high-resolution (HR) T1 TSE sequence. Radiographs of the wrist were acquired for the patient group. When comparing patients and volunteers (unadjusted for gender and age), we found a statistically significant difference of horizontal and vertical fractal dimensions (FDs) using 7T T1 TSE-HR images in low-resolution mode (horizontal: p = 0.04, vertical: p = 0.01). When comparing radiography to the different MRI sequences, we found a statistically significant difference for low- and high-resolution horizontal FDs between radiography and 3T T1 TSE and 7T T1 TSE-HR. Vertical FDs were significantly different only between radiographs and 3T T1 TSE in the high-resolution mode; FSA measures obtained from 3T and 7T MRI are highly dependent on the sequence and reconstruction resolution used, and thus are not easily comparable between MRI systems and applied sequences.
2
Held, Paul. "MRI of orofacial tumors and paragangliomas with 2D GE sequences: indications and optimal sequence parameters." European Journal of Radiology 18, no. 1 (February 1994): 38–44. http://dx.doi.org/10.1016/0720-048x(94)90364-6.
Full text
3
Soltanian-Zadeh, H., R. Saigal, J. P. Windham, A. E. Yagle, and D. O. Hearshen. "Optimization of MRI protocols and pulse sequence parameters for eigenimage filtering." IEEE Transactions on Medical Imaging 13, no. 1 (March 1994): 161–75. http://dx.doi.org/10.1109/42.276155.
Full text
4
Wilson, M., P. Morgan, and L. Blumhardt. "Quantitative diffusion characteristics of the human brain depend on MRI sequence parameters." Neuroradiology 44, no. 7 (July 2002): 586–91. http://dx.doi.org/10.1007/s00234-002-0797-8.
Full text
5
Ford, John, Nesrin Dogan, Lori Young, and Fei Yang. "Quantitative Radiomics: Impact of Pulse Sequence Parameter Selection on MRI-Based Textural Features of the Brain." Contrast Media & Molecular Imaging 2018 (July 30, 2018): 1–9. http://dx.doi.org/10.1155/2018/1729071.
Full textAbstract:
Objectives. Radiomic features extracted from diverse MRI modalities have been investigated regarding their predictive and/or prognostic value in a variety of cancers. With the aid of a 3D realistic digital MRI phantom of the brain, the aim of this study was to examine the impact of pulse sequence parameter selection on MRI-based textural parameters of the brain. Methods. MR images of the employed digital phantom were realized with SimuBloch, a simulation package made for fast generation of image sequences based on the Bloch equations. Pulse sequences being investigated consisted of spin echo (SE), gradient echo (GRE), spoiled gradient echo (SP-GRE), inversion recovery spin echo (IR-SE), and inversion recovery gradient echo (IR-GRE). Twenty-nine radiomic textural features related, respectively, to gray-level intensity histograms (GLIH), cooccurrence matrices (GLCOM), zone size matrices (GLZSM), and neighborhood difference matrices (GLNDM) were evaluated for the obtained MR realizations, and differences were identified. Results. It was found that radiomic features vary considerably among images generated by the five different T1-weighted pulse sequences, and the deviations from those measured on the T1 map vary among features, from a few percent to over 100%. Radiomic features extracted from T1-weighted spin-echo images with TR varying from 360 ms to 620 ms and TE = 3.4 ms showed coefficients of variation (CV) up to 45%, while up to 70%, for T2-weighted spin-echo images with TE varying over the range 60–120 ms and TR = 6400 ms. Conclusion. Variability of radiologic textural appearance on MR realizations with respect to the choice of pulse sequence and imaging parameters is feature-dependent and can be substantial. It calls for caution in employing MRI-derived radiomic features especially when pooling imaging data from multiple institutions with intention of correlating with clinical endpoints.
6
Shahi, Anamika, Satya Sundar Gajendra Mohapatra, and Supriya Mishra. "MRI evaluation of pediatric posterior fossa tumors and its correlation with histopathology: A prospective observational study." Journal of Associated Medical Sciences 56, no. 1 (January 3, 2023): 121–32. http://dx.doi.org/10.12982/jams.2023.015.
Full textAbstract:
Background: The commonest malignancy in the pediatric age group is leukemia, followed by brain tumors. Pediatric brain tumors are usually seen in children below 10 years. The incidence ranges from 1 to 3 per 100,000 cases. Primary intracranial tumors most commonly occur in the posterior fossa in children while infratentorial tumors are predominant in children over 4 years. Infratentorial tumors are more common overall, accounting for 45-60% of all cases. Physiologic characteristics of the pediatric posterior fossa tumors are well represented in advanced MRI techniques, which results in better pre-operative tumor evaluation, and often better results. Objectives: Primary intracranial tumors most commonly occur in the posterior fossa in children. Treatment and prognosis rely heavily on correct diagnosis. The most important modality for early diagnosis is MRI of the brain. This study aims to evaluate the role of MRI in pediatric posterior fossa tumors. Materials and methods: Thirty-three patients in the pediatric age group (<18 years) with a clinical suspicion of posterior fossa tumors, referred to the department of Radiology for undergoing MRI of the brain with contrast were included in the study. These patients underwent surgery followed by histopathological examination (HPE). Five parameters from conventional MRI were chosen and correlated with histopathology (gold standard). Statistical analysis was done subsequently. Results: Diffusion-weighted imaging (DWI) is the most accurate parameter (94%), followed by T2 weighted imaging (T2WI), gradient, and post-contrast sequence (91% each). Diffusion-weighted imaging and post-contrast sequence had the highest specificity (almost 96%) while DWI and T2WI had the highest sensitivity (90% each). All 5 parameters are useful in 85% of cases. Overall diagnostic accuracy of MRI was almost 94% compared to histopathology. Conclusion: DWI is the best parameter, followed by T2WI, gradient imaging, and post-contrast sequence. MRI is highly accurate in the evaluation of pediatric posterior fossa tumors. In centers where advanced MRI techniques cannot be performed, some parameters from conventional MRI can be selected that aid in diagnosis. Our study shows that judicious use of 5 parameters can increase sensitivity, specificity, and diagnostic accuracy of MRI for pediatric posterior fossa tumors.
7
Patel, Daxa M., R. Shane Tubbs, Gigi Pate, James M. Johnston, and Jeffrey P. Blount. "Fast-sequence MRI studies for surveillance imaging in pediatric hydrocephalus." Journal of Neurosurgery: Pediatrics 13, no. 4 (April 2014): 440–47. http://dx.doi.org/10.3171/2014.1.peds13447.
Full textAbstract:
Object Surveillance imaging of the cerebral ventricles can be valuable in following up children with shunt-treated hydrocephalus. There also, however, has been recent increased awareness and concern over the potential risk associated with imaging-related radiation exposure in children. Magnetic resonance imaging represents an imaging alternative that does not use ionizing radiation; however, its practical utility has been limited due to the near-uniform requirement for sedation or general anesthesia in children. Magnetic resonance imaging without sedation is often futile because of the movement artifact produced by the nonsedated pediatric patient. Some studies have demonstrated the feasibility of using fast-sequence MRI (fsMRI), but the reported experiences are limited. The authors have incorporated fsMRI into their routine shunt surveillance imaging paradigms and report here a 5-year experience with this modality. Methods The authors initially started using fsMRI for routine surveillance in a single clinic in 2008 and have gradually increased their institutional utilization of this modality as experience has accumulated and protocols have been refined. Imaging sequences obtained for each child include an axial T2-weighted half-Fourier acquisition single-shot turbo spin-echo (HASTE), coronal T2-weighted HASTE, and sagittal T2-weighted HASTE images. The authors conducted a retrospective chart and imaging review. They rated each fsMR image according to 5 visibility parameters: 1) ventricle size, 2) ventricle configuration, 3) presence or absence of transependymal flow, 4) presence or absence of motion artifact, and 5) visualization of the ventricular catheter. Each parameter was graded as 1 (present) or 0 (absent). Thus, the maximum value assigned to each scan could be 5 and the minimum value assigned to each scan could be 0. Interrater reliability between pairs of observers was calculated using the Kendall's tau-b and intraclass coefficients. Results Two hundred patients underwent fsMRI. No child required sedation. The average duration of examinations was approximately 3.37 minutes, and mean age of the patients was 5.7 years. Clinically useful images were attained in all cases. Overall quality of the fsMRI studies based on the 5 different visibility parameters showed that 169 images (84.5%) included 4 or 5 parameters (score ≥ 4) and had statistically significant excellent quality. The Kendall's tau-b for the overall fsMRI ratings was 0.82 (p = 0.002) and the intraclass coefficient was 0.87 (p < 0.0001). Conclusions In the present cohort of 200 patients, fsMRI studies were shown to have an excellent overall quality and a statistically significant high degree of interrater reliability. Consequently, the authors propose that fsMRI is a sufficiently effective modality that eliminates the need for sedation and the use of ionizing radiation and that it should supplant CT for routine surveillance imaging in hydrocephalic patients.
8
Chen, Wen-Chang, Yen-Hung Ho, Song-Shei Lin, Lan Zhang, I.-Tsang Chiang, and Wei-Ming Lin. "Sensitivity of Pre-Contrast Multiphase versus Conventional Liver MRI in Diagnosing Hepatic Hemangioma." Journal of Medical Imaging and Health Informatics 10, no. 11 (November 1, 2020): 2728–32. http://dx.doi.org/10.1166/jmihi.2020.3207.
Full textAbstract:
Hepatic hemangioma (HH) can be diagnosed noninvasively via dynamic contrast enhancement computed tomography, magnetic resonance imaging (MRI) or ultrasonography. Diagnosis HH is based on imaging features such as early arterial phase enhancement and persistence enhancement on portal or delayed phase. However, differentiating small or atypical hemangiomas from other hepatic masses using these imaging methods maybe be difficult, especially in patients with a medical history of malignant disease. Another challenge in clinical practice is when patients with acute or chronic renal insufficiency, use MRI contrast agent gadolinium (Gd) with the risk of nephrogenic systemic fibrosis. Differentiating hemangioma from its mimickers on preoperative imaging studies is of critical importance. Our study compared the diagnostic sensitivity of pre-contrast multiphase and conventional liver MRI. Total 80 patients with HH were participate to our study retrospectively. Imaging was performed using pre-contrast multiphase and conventional liver MRI methods. The size of the nodule/mass to be evaluated was ≥1 cm. All patients MRI images were obtained and classified into two groups based on the acquisition parameters. The first group with pre-contrast multiphase MRI sequences, and the second group of conventional liver MRI methods included pre-contrast multiphase MRI sequences, contrast-enhanced tri-phase sequences. The study was reviewed and analyzed by two independence gastrointestinal radiologists, who were blinded to the examination and follow-up study results. The diagnostic sensitivity was compared between pre-contrast multiphase MRI sequences only and conventional liver MRI sequences methods. Based on the observation of two gastrointestinal radiologists, our results showed mean sensitivity of 90.0% and 97.5% for pre-contrast multiphase MRI and conventional liver MRI, respectively. Pre-contrast multiphase MRI sequence methods may be reliably applied in the diagnosis of HH.
9
Thieleking, Ronja, Rui Zhang, Maria Paerisch, Kerstin Wirkner, Alfred Anwander, Frauke Beyer, Arno Villringer, and A. Veronica Witte. "Same Brain, Different Look?—The Impact of Scanner, Sequence and Preprocessing on Diffusion Imaging Outcome Parameters." Journal of Clinical Medicine 10, no. 21 (October 27, 2021): 4987. http://dx.doi.org/10.3390/jcm10214987.
Full textAbstract:
In clinical diagnostics and longitudinal studies, the reproducibility of MRI assessments is of high importance in order to detect pathological changes, but developments in MRI hard- and software often outrun extended periods of data acquisition and analysis. This could potentially introduce artefactual changes or mask pathological alterations. However, if and how changes of MRI hardware, scanning protocols or preprocessing software affect complex neuroimaging outcomes from, e.g., diffusion weighted imaging (DWI) remains largely understudied. We therefore compared DWI outcomes and artefact severity of 121 healthy participants (age range 19–54 years) who underwent two matched DWI protocols (Siemens product and Center for Magnetic Resonance Research sequence) at two sites (Siemens 3T Magnetom Verio and Skyrafit). After different preprocessing steps, fractional anisotropy (FA) and mean diffusivity (MD) maps, obtained by tensor fitting, were processed with tract-based spatial statistics (TBSS). Inter-scanner and inter-sequence variability of skeletonised FA values reached up to 5% and differed largely in magnitude and direction across the brain. Skeletonised MD values differed up to 14% between scanners. We here demonstrate that DTI outcome measures strongly depend on imaging site and software, and that these biases vary between brain regions. These regionally inhomogeneous biases may exceed and considerably confound physiological effects such as ageing, highlighting the need to harmonise data acquisition and analysis. Future studies thus need to implement novel strategies to augment neuroimaging data reliability and replicability.
10
Drake-Pérez, M., B. M. A. Delattre, J. Boto, A. Fitsiori, K. O. Lovblad, S. Boudabbous, and M. I. Vargas. "Normal Values of Magnetic Relaxation Parameters of Spine Components with the Synthetic MRI Sequence." American Journal of Neuroradiology 39, no. 4 (March 1, 2018): 788–95. http://dx.doi.org/10.3174/ajnr.a5566.
Full text
11
Mastropietro, Alfonso, Elisabetta De Bernardi, Gian Luca Breschi, Ileana Zucca, Massimo Cametti, Chiara Dolores Soffientini, Marco de Curtis, et al. "Optimization of rapid acquisition with relaxation enhancement (RARE) pulse sequence parameters for19F-MRI studies." Journal of Magnetic Resonance Imaging 40, no. 1 (November 13, 2013): 162–70. http://dx.doi.org/10.1002/jmri.24347.
Full text
12
Přibil, Jiří, Anna Přibilová, and Ivan Frollo. "Analysis of the Influence of Different Settings of Scan Sequence Parameters on Vibration and Noise Generated in the Open-Air MRI Scanning Area." Sensors 19, no. 19 (September 27, 2019): 4198. http://dx.doi.org/10.3390/s19194198.
Full textAbstract:
A system of gradient coils of the magnetic resonance imaging (MRI) device produces significant vibration and noise. Energetic relations of these phenomena are analyzed depending on MRI scan parameters (sequence type, repetition time (TR), echo time (TE), slice orientation, body weight). This issue should be investigated because of negative physiological and psychological effects on a person exposed to vibration and acoustic noise. We also measured the sound pressure level in the MRI scanning area and its vicinity in order to minimize these negative impacts, depending on intensity and time duration of exposition. From the recorded vibration and noise signals, the energy parameters were determined and statistically analyzed, and the obtained results were visually and numerically compared. Finally, subjective evaluation by a listening test method was used to analyze the influence of the generated MRI noise on the human psyche.
13
Sahoo, Prativa, Paul Frankel, Julie Ressler, Margarita Gutova, Alexander J. Annala, Behnam Badie, Jana Portnow, Karen S. Aboody, Massimo D’Apuzzo, and Russell C. Rockne. "Early Changes in Tumor Perfusion from T1-Weighted Dynamic Contrast-Enhanced MRI following Neural Stem Cell-Mediated Therapy of Recurrent High-Grade Glioma Correlate with Overall Survival." Stem Cells International 2018 (2018): 1–9. http://dx.doi.org/10.1155/2018/5312426.
Full textAbstract:
Background. The aim of this study was to correlate T1-weighted dynamic contrast-enhanced MRI- (DCE-MRI-) derived perfusion parameters with overall survival of recurrent high-grade glioma patients who received neural stem cell- (NSC-) mediated enzyme/prodrug gene therapy. Methods. A total of 12 patients were included in this retrospective study. All patients were enrolled in a first-in-human study (NCT01172964) of NSC-mediated therapy for recurrent high-grade glioma. DCE-MRI data from all patients were collected and analyzed at three time points: MRI#1—day 1 postsurgery/treatment, MRI#2— day 7 ± 3 posttreatment, and MRI#3—one-month follow-up. Plasma volume (Vp), permeability (Ktr), and leakage (λtr) perfusion parameters were calculated by fitting a pharmacokinetic model to the DCE-MRI data. The contrast-enhancing (CE) volume was measured from the last dynamic phase acquired in the DCE sequence. Perfusion parameters and CE at each MRI time point were recorded along with their relative change between MRI#2 and MRI#3 (Δ32). Cox regression was used to analyze patient survival. Results. At MRI#1 and at MRI#3, none of the parameters showed a significant correlation with overall survival (OS). However, at MRI#2, CE and λtr were significantly associated with OS (p<0.05). The relative λtr and Vp from timepoint 2 to timepoint 3 (Δ32λtr and Δ32Vp) were each associated with a higher hazard ratio (p<0.05). All parameters were highly correlated, resulting in a multivariate model for OS including only CE at MRI#2 and Δ32Vp, with an R2 of 0.89. Conclusion. The change in perfusion parameter values from 1 week to 1 month following NSC-mediated therapy combined with contrast-enhancing volume may be a useful biomarker to predict overall survival in patients with recurrent high-grade glioma.
14
Чехонин, В. П., А. Г. Мажуга, А. Н. Багдинова, А. С. Рыбаков, Е. И. Демихов, Т. Е. Демихов, В. В. Лысенко, et al. "A full-size first-in-Russia MRI high resolution complex with a 1.5 Tesla superconducting magnet." Nauchno-prakticheskii zhurnal «Patogenez», no. 4() (December 11, 2018): 71–80. http://dx.doi.org/10.25557/2310-0435.2018.04.71-80.
Full textAbstract:
Представлен первый отечественный полноразмерный магнитно-резонансный томограф МРТ4.1 для широкого спектра применений, выполненный на базе сверхпроводящего магнита с полем 1,5 Тл. Описано программное обеспечение, позволяющее реализовывать любые последовательности изображений. Томограф и программное обеспечение имеют параметры, не уступающие западным производителям. Преимуществом МРТ является возможность изменять физические параметры магнита и свободный программный код, что представляет интерес для исследователей и продвинутых пользователей. The article presents a first-in-Russia MRI system for vast scope of applications based on a 1.5 Tesla superconducting magnet and describes the software capable to produce any sequence of images. The MRI and software parameters are not inferior to those provided by MRI production leaders. The advantage of this MRI system is a possibility to change magnet field parameters and the free program code, which is interesting for researchers and advanced users.
15
Lucic, Milos, Katarina Koprivsek, Viktor Till, and Zoran Vesic. "Dynamic magnetic resonance imaging of the cerebrospinal fluid flow within the cerebral aqueduct by different FISIP 2D sequences." Vojnosanitetski pregled 67, no. 5 (2010): 357–63. http://dx.doi.org/10.2298/vsp1005357l.
Full textAbstract:
Background/Aim. A vast majority of current radiogical techniques, such as computerized tomography (CT) and magnetic resonance imaging (MRI) have great potential of visualization and delineation of cerebrospinal fluid spaces morphology within cerebral aqueduct. The aim of this study was to determine the possibilities of two differently acquired FISP (Fast Imaging with Steady State Precession) 2D MR sequences in the estimation of the pulsatile cerebrospinal fluid (CSF) flow intensity through the normal cerebral aqueduct. Methods. Sixty eight volunteers underwent brain MRI on 1.5T MR imager with additionally performed ECG retrospectively gated FISP 2D sequences (first one, as the part of the standard software package, with following technical parameters: TR 40, TE 12, FA 17, Matrix: 192 ? 256, Acq 1, and the second one, experimentally developed by our investigation team: TR 30, TE 12, FA 70, Matrix: 192 ? 256, Acq 1) respectively at two fixed slice positions - midsagittal and perpendicular to cerebral aqueduct, displayed and evaluated by multiplegated images in a closed-loop cinematographic (CINE) format. Results. Normal brain morphology with preserved patency of the cerebral aqueduct in all of 68 healthy volunteers was demonstrated on MRI examination. Cerebrospinal fluid flow within the cerebral aqueduct was distinguishable on both CINE MRI studies in midsagittal plane, but the estimation of intraaqueductal CSF flow in perpendicular plane was possible on CINE MRI studies acquired with experimentally improved FISP 2D (TR 30, FA 70) sequence only. Conclusion. Due to the changes of technical parameters CINE MRI study acquired with FISP 2D (TR 30, FA 70) in perpendicular plane demonstrated significantly higher capability in the estimation of the CSF pulsation intensity within the cerebral aqueduct. .
16
Wahab, Rifat A., Kyle Lewis, Charmi Vijapura, Bin Zhang, Su-Ju Lee, Ann Brown, and Mary C. Mahoney. "Textural Characteristics of Biopsy-proven Metastatic Axillary Nodes on Preoperative Breast MRI in Breast Cancer Patients: A Feasibility Study." Journal of Breast Imaging 2, no. 4 (July 2020): 361–71. http://dx.doi.org/10.1093/jbi/wbaa038.
Full textAbstract:
Abstract Objective To determine the diagnostic accuracy of MRI textural analysis (TA) to differentiate malignant from benign axillary lymph nodes in patients with breast cancer. Methods This was an institutional review board–approved retrospective study of axillary lymph nodes in women with breast cancer that underwent ultrasound-guided biopsy and contrast-enhanced (CE) breast MRI from January 2015 to December 2018. TA of axillary lymph nodes was performed on 3D dynamic CE T1-weighted fat-suppressed, 3D delayed CE T1-weighted fat-suppressed, and T2-weighted fat-suppressed MRI sequences. Quantitative parameters used to measure TA were compared with pathologic diagnoses. Areas under the curve (AUC) were calculated using receiver operating characteristic curve analysis to distinguish between malignant and benign lymph nodes. Results Twenty-three biopsy-proven malignant lymph nodes and 24 benign lymph nodes were analyzed. The delayed CE T1-weighted fat-suppressed sequence had the greatest ability to differentiate malignant from benign outcome at all spatial scaling factors, with the highest AUC (0.84–0.93), sensitivity (0.78 [18/23] to 0.87 [20/23]), and specificity (0.76 [18/24] to 0.88 [21/24]). Kurtosis on the 3D delayed CE T1-weighted fat-suppressed sequence was the most prominent TA parameter differentiating malignant from benign lymph nodes (P < 0.0001). Conclusion This study suggests that MRI TA could be helpful in distinguishing malignant from benign axillary lymph nodes. Kurtosis has the greatest potential on 3D delayed CE T1-weighted fat-suppressed sequences to distinguish malignant and benign lymph nodes.
17
Wang, Hongyan, Lixia Zhu, Guohua Li, Menzhe Zuo, Xi Ma, and Jianliang Wang. "Perfusion parameters of intravoxel incoherent motion based on tumor edge region of interest in cervical cancer: evaluation of differentiation and correlation with dynamic contrast-enhanced MRI." Acta Radiologica 61, no. 8 (December 11, 2019): 1087–95. http://dx.doi.org/10.1177/0284185119890086.
Full textAbstract:
Background Intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) is a functional magnetic resonance imaging (MRI) sequence. Purpose To evaluate the value of perfusion parameters derived from IVIM-DWI based on tumor edge region of interest (ROI) in differentiation in cervical cancer and investigate the relationship between IVIM and dynamic contrast-enhanced MRI (DCE-MRI). Material and Methods Thirty-three patients with pathologically diagnosed squamous cell carcinoma who underwent IVIM-DWI (nine b-values: 1–1000 s/mm2) and DCE-MRI were retrospectively assessed in this study. Parameters of IVIM (D, f, D*, fD*) and quantitative parameters of DCE-MRI (Ktrans, Kep, Ve) were derived using tumor edge ROI. Mann–Whitney U test was used to compare parameters between pathological grades and receiver operating characteristic (ROC) curves were used. Pearson’s correlation coefficient (r) evaluated the correlation between perfusion parameters derived from IVIM and DCE-MRI. Results The poorly differentiated group showed the significantly lower D value and the higher f, Ktrans and Kep values than the well-to-moderately differentiated group ( P < 0.05). ROC curves indicated that f < 26%, Ktrans <0.38/min, and Kep <1.62/min could differentiate the poorly differentiated group from the well-to-moderately differentiated group (AUC 0.753–0.808). Significantly positive correlations were found between f and Ktrans (r = 0.422, P = 0.014) and between fD* and Ktrans (r = 0.448, P = 0.009). Conclusion Perfusion parameters derived from IVIM based on tumor edge ROI may offer additional value in differentiation in cervical cancer, and the IVIM perfusion parameters showed moderate positive correlations with quantitative perfusion parameters from DCE-MRI, while f and fD* showed promising significance.
18
Sullivan, Thomas P., Matthew M. Harkenrider, Murat Surucu, Abbie M. Wood, Joseph H. Yacoub, and Steven M. Shea. "Reduction of MRI signal distortion from titanium intracavitary brachytherapy applicator by optimizing pulse sequence parameters." Brachytherapy 17, no. 2 (March 2018): 377–82. http://dx.doi.org/10.1016/j.brachy.2017.10.013.
Full text
19
Abreu Junior, Luiz de, Laiz Laura de Godoy, Luciana Pinheiro dos Santos Vaz, André Evangelista Torres, Angela Maria Borri Wolosker, Ulysses Santos Torres, and Maria Lucia Borri. "Optimization of magnetic resonance imaging protocol for the diagnosis of transient global amnesia." Radiologia Brasileira 52, no. 3 (June 2019): 161–65. http://dx.doi.org/10.1590/0100-3984.2018.0028.
Full textAbstract:
Abstract Objective: To emphasize the most appropriate magnetic resonance imaging (MRI) diffusion protocol for the detection of lesions that cause transient global amnesia, in order to perform an accurate examination, as well as to determine the ideal time point after the onset of symptoms to perform the examination. Materials and Methods: We evaluated five patients with a diagnosis of transient global amnesia treated between 2012 and 2015. We analyzed demographic characteristics, clinical data, symptom onset, diffusion techniques, and radiological findings. Examination techniques included a standard diffusion sequence (b value = 1000 s/mm2; slice thickness = 5 mm) and a optimized diffusion sequence (b value = 2000 s/mm2; slice thickness = 3 mm). Results: Brain MRI was performed at 24 h or 36 h after symptom onset, except in one patient, in whom it was performed at 12 h after (at which point no changes were seen) and repeated at 36 h after symptom onset (at which point it showed alterations in the right hippocampus). The standard and optimized diffusion sequences were both able to demonstrate focal changes in the hippocampi in all of the patients but one, in whom the changes were demonstrated only in the optimized sequence. Conclusion: MRI can confirm a clinical hypothesis of transient global amnesia. Knowledge of the optimal diffusion parameters and the ideal timing of diffusion-weighted imaging (> 24 h after symptom onset) are essential to improving diagnostic efficiency.
20
Mousavi, Farnoush, Fariborz Faeghi, Hamed Javadian, Hamidreza Haghighatkhah, and Saeed Oraee-Yazdani. "Evaluating the Origin of the Brain Metastatic Tumors by Using DWI Parameters." International Clinical Neuroscience Journal 6, no. 3 (August 31, 2019): 92–97. http://dx.doi.org/10.15171/icnj.2019.18.
Full textAbstract:
Background: Brain metastases are the most common tumors in the human central nervous system (CNS), with an occurrence 10 times higher than primary brain tumors in adults. A radiologist usually diagnoses these tumors. Typically, magnetic resonance imaging (MRI) has been used to evaluate the status and number of metastases, the design of surgical treatment or radiotherapy, and the response to treatment. This study aimed to consider the origin of metastatic tumors of the brain using diffusionweighted imaging sequence. Methods: In this study, 95 lesions observed in 51 patients with different types of brain metastasis who analyzed with standard brain MRI protocols such as T2-weighted fast spin-echo in sagittal, coronal and axial planes and T1-weighted spin-echo sequences before and after injection of contrast enhancement and diffusion-weighted imaging. The diffusion-weighted imaging included an echoplanar spin-echo sequence with two b values (0,1000 s/mm) and calculated apparent diffusion coefficient (ADC) maps. We measured the ADC-value on normalized ADC maps and compared them with different methods. ANOVA was used to compare ADC among all groups as well as T-test for every two groups. Results: The results showed that patients with lung cancer (squamous cell carcinoma, SCC) had the lowest mean ADC (658.70*10-3 mm2 /s) and breast cancer patients with the highest mean ADC(935.52*10-3 mm2 /s). This study demonstrated that most Brain metastases had low and intermediate ADC values. The analysis showed no significant difference among all groups. However, ADC values in breast cancer and kidney and lung (adenocarcinoma) were statistically higher in comparison to other groups. There were no critical discrepancies between ADC values in brain metastases from Breast cancer and lung cancer (adenocarcinoma) and kidney. Conclusion: It seems that evaluating the origin of the brain metastatic tumors by using diffusion imaging (DWI) parameters could be helpful to prevent invasive methods like biopsies in some situations. Although it needs more studies to achieve this purpose.
21
Chen, Chien-Wei, Yuan-Hsi Tseng, Min Yi Wong, Chao-Ming Wu, Bor-Shyh Lin, and Yao-Kuang Huang. "Stasis Leg Ulcers: Venous System Revises by Triggered Angiography Non-Contrast-Enhanced Sequence Magnetic Resonance Imaging." Diagnostics 10, no. 9 (September 17, 2020): 707. http://dx.doi.org/10.3390/diagnostics10090707.
Full textAbstract:
Objectives: The distribution of venous pathology in stasis leg ulcers is unclear. The main reason for this uncertainty is the lack of objective diagnostic tools. To fill this gap, we assessed the effectiveness of triggered angiography non-contrast-enhanced (TRANCE)-magnetic resonance imaging (MRI) in determining the venous status of patients with stasis leg ulcers. Methods: This prospective observational study included the data of 23 patients with stasis leg ulcers who underwent TRANCE-MRI between April 2017 and May 2020; the data were retrospectively analyzed. TRANCE MRI utilizes differences in vascular signal intensity during the cardiac cycle for subsequent image subtraction, providing not only a venogram but also an arteriogram without the use of contrast agents or radiation. Results: TRANCE MRI revealed that the stasis leg ulcers of nine of the 23 patients could be attributed to valvular insufficiency and venous occlusion (including deep venous thrombosis [DVT], May–Thurner syndrome, and other external compression). Moreover, TRANCE MRI demonstrated no venous pathology in five patients (21.7%). We analyzed TRANCE MRI hemodynamic parameters, namely stroke volume, forward flow volume, backward flow volume, regurgitant fraction, absolute volume, mean flux, stroke distance, and mean velocity, in the external iliac vein, femoral vein, popliteal vein, and great saphenous vein (GSV) in three of the patients with valvular insufficiency and three of those with venous occlusion. We found that the mean velocity and stroke volume in the GSV was higher than that in the popliteal vein in all patients with venous valvular insufficiency. Conclusions: Stasis leg ulcers may have no underlying venous disease and could be confirmed by TRANCE-MRI. TRANCE MRI has good Interrater reliability between Duplex study in greater saphenous venous insufficiency. It also potentially surpasses existing diagnostic modalities in terms of distinguishable hemodynamic figures. Accordingly, TRANCE-MRI is a safe and useful tool for examining stasis leg ulcers and is extensively applied currently.
22
Morán, Luz M., Jesús Vega, Nieves Gómez-León, and Ana Royuela. "Myxomas and myxoid liposarcomas of the extremities: Our preliminary findings in conventional, perfusion, and diffusion magnetic resonance." Acta Radiologica Open 11, no. 10 (October 2022): 205846012211314. http://dx.doi.org/10.1177/20584601221131481.
Full textAbstract:
Background The differentiation between myxomas and myxoid liposarcomas (MLPS) often is a serious challenge for the radiologists. Magnetic resonance imaging (MRI) is the most useful imaging technique in characterization of the soft tissue tumors (STT). Purpose To evaluate in a sample of myxomas and MLPS of the extremities, what morphological findings in conventional MRI allow us to differentiate these two types of myxoid tumors, in addition to analyzing the validity of the apparent diffusion coefficient (ADC) values of diffusion-weighted MRI (DW-MRI). Material and Methods Magnetic resonance imaging studies in myxomas and MLPS of extremities searched in our PACS between 2015 and 2019. All studies had conventional MRI with T1, T2, and PD SPAIR sequences, while DW-MRI with ADC mapping and perfusion MRI with a T1 sequence repeated for 4 minutes after contrast injection were additional sequences only in some explorations. Two radiologists evaluated independently the MRI studies by examining the qualitative parameters. Apparent diffusion coefficient values were calculated using two methods—ADC global and ADC solid, and Receiver Operating Characteristic (ROC) curves were applied for analysis. Results The features were consistent with MLPS: size greater than 10 cm, heterogeneous signal on T1, and nodular enhancement, while the common findings for myxomas were a homogenously hypointense signal on T1 and diffuse peritumoral enhancement. The solid and global ADC values were higher in myxomas. We observed that the solid ADC value less than 2.06 x 10−3mm2 x s would support the diagnosis of MLPS against myxoma. Conclusion Overall, MRI with its different modalities improved the diagnostic accuracy when differentiating myxomas from MLPS of extremities.
23
Büchert, Martin, and Klaus Mross. "Ir-truefisp: A New Dce-mri Approach in Comparison with 3d-flash Multi Flip Angle Method." Magnetic Resonance Insights 5 (January 2012): MRI.S9832. http://dx.doi.org/10.4137/mri.s9832.
Full textAbstract:
For assessing treatment response to novel cancer therapeutics, dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) is a valuable tool. Quantitative functional parameter estimates can be obtained by fitting physiological models to the data. In this study the IR-TrueFISP approach was evaluated as DCE-MRI acquisition sequence against the widely used 3D-Flash protocol. For comparison both protocols providing different spatial and temporal information were investigated in phantom and patient examinations. 12 advanced tumor patients underwent two examinations on consecutive days using both protocols. Results were compared and were in good agreement with each other. IR-TrueFISP data showed a lower variability compared to 3D-Flash results. This work demonstrates the pros and cons of both investigated methods. It was demonstrated that the known IR-TrueFISP sequence can successfully be employed as DCE-MRI acquisition method estimating perfusion parameters. The benefits of the IR-TrueFISP protocol are high temporal resolution and good accuracy.
24
Zhang, S., D. D. Lichti, J. C. Küpper, and J. L. Ronsky. "AN AUTOMATIC ICP-BASED 2D-3D REGISTRATION METHOD FOR A HIGH-SPEED BIPLANAR VIDEORADIOGRAPHY IMAGING SYSTEM." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B2-2020 (August 12, 2020): 805–12. http://dx.doi.org/10.5194/isprs-archives-xliii-b2-2020-805-2020.
Full textAbstract:
Abstract. High-Speed Biplanar Videoradiography (HSBV) is an X-ray based non-invasive imaging system that can be used to derive dynamic bony translations and rotations. The 2D-3D registration process matches a 3D bone model acquired from magnetic resonance imaging (MRI) or computed tomography (CT) scans with the 2D X-ray image pairs. This study focuses on the registration of MRI data as it can acquire detailed soft tissue contrast that cannot be easily discerned in CT scans. A novel 2D-3D registration method is reported in this paper that is suitable for the MRI-based bone models with high precision and high efficiency. In addition, an automatic initialization procedure with 64 starting poses is established to avoid user intervention in the registration. The method has been tested using the HSBV image sequence of a knee joint during walking. Thirty-five consecutive poses from the sequence were tested for the registration, and 50 non-consecutive poses randomly selected from the sequence were tested for the automatic initialization. The registration precision for each axis was 0.49 to 0.54 mm. For the initialization validation test, 48 over 50 frames were successfully initialized and two failed due to portions of the joint falling outside of the field-of-view of the system. The average time for each initialization is only about 6 min. The improved 2D-3D registration will allow determination of precise 3D kinematic parameters with high efficiency. These kinematic parameters can be used to calculate joint cartilage contact mechanics that provide insight into the mechanical processes and mechanisms of joint degeneration or pathology.
25
Bohner, Lauren, Pedro Tortamano, Norbert Meier, Felix Gremse, Johannes Kleinheinz, and Marcel Hanisch. "Trabecular Bone Assessment Using Magnetic-Resonance Imaging: A Pilot Study." International Journal of Environmental Research and Public Health 17, no. 24 (December 11, 2020): 9282. http://dx.doi.org/10.3390/ijerph17249282.
Full textAbstract:
The aim of this study was to assess trabecular bone morphology via magnetic-resonance imaging (MRI) using microcomputed tomography (µCT) as the control group. Porcine bone samples were scanned with T1-weighted turbo spin echo sequence imaging, using TR 25 ms, TE 3.5 ms, FOV 100 × 100 × 90, voxel size 0.22 × 0.22 × 0.50 mm, and scan time of 11:18. µCT was used as the control group with 80 kV, 125 mA, and a voxel size of 16 µm. The trabecular bone was segmented on the basis of a reference threshold value and morphological parameters. Bone volume (BV), Bone-volume fraction (BvTv), Bone specific surface (BsBv), trabecular thickness (TbTh), and trabecular separation (TbSp) were evaluated. Paired t-test and Pearson correlation test were performed at p = 0.05. MRI overestimated BV, BvTv, TbTh, and TbSp values. BsBv was the only parameter that was underestimated by MRI. High statistical correlation (r = 0.826; p < 0.05) was found for BV measurements. Within the limitations of this study, MRI overestimated trabecular bone parameters, but with a statistically significant fixed linear offset.
26
Lokannavar, Harish S., Xiaochun Yang, and Harsha Guduru. "Arthroscopic and Low-Field MRI (0.25 T) Evaluation of Meniscus and Ligaments of Painful Knee." Journal of Clinical Imaging Science 2 (May 23, 2012): 24. http://dx.doi.org/10.4103/2156-7514.96539.
Full textAbstract:
Objective: Magnetic resonance imaging (MRI) is an accurate, non-invasive, cost-effective technique for examination of the soft tissue and osseous structures of the knee. The purpose of this study was to evaluate the accuracy of low-field MRI by comparing the results with subsequent arthroscopy. Materials and Methods: MR imaging study of 146 patients was done using 0.25 T ESTOATE G-SCAN and the sequence used were SE, FSE and GRE in all the three planes. The comparison was based on five parameters: accuracy, sensitivity, specificity, positive predictive value, and negative predictive value. Result: Our study showed high accuracy (98.08%) and negative predictive value (98.62%) for MRI in comparison with arthroscopy. Conclusion: Low-field MRI alleviates the need of arthroscopy for detection of meniscus tears and ligament tears.
27
Přibil, Jiří, Anna Přibilová, and Ivan Frollo. "Analysis of Energy Relations between Noise and Vibration Signals in the Scanning Area of an Open-Air MRI Device." Proceedings 4, no. 1 (November 14, 2018): 29. http://dx.doi.org/10.3390/ecsa-5-05730.
Full textAbstract:
The paper analyzes the influence of different magnetic resonance (MR) scan sequence parameters (echo time, repetition time, orientation of scan slices, sequence type, mass of a tested object) on the energy of the produced noise and vibration. The measured sound pressure levels, together with the recorded noise and vibration signals, were stored in a database and then processed using similar methods to speech signal analysis because the main frequencies of the acoustic noise and vibration lie in the standard audio frequency range. In the signal processing phase, four types of parameters describing the signal energy were determined and statistically analyzed, and the obtained results were visually and numerically compared.
28
Gadda, Giacomo, Sirio Cocozza, Mauro Gambaccini, Angelo Taibi, Enrico Tedeschi, Paolo Zamboni, and Giuseppe Palma. "NO-HYPE: a novel hydrodynamic phantom for the evaluation of MRI flow measurements." Medical & Biological Engineering & Computing 59, no. 9 (August 8, 2021): 1889–99. http://dx.doi.org/10.1007/s11517-021-02390-2.
Full textAbstract:
Abstract Accurate and reproducible measurement of blood flow profile is very important in many clinical investigations for diagnosing cardiovascular disorders. Given that many factors could affect human circulation, and several parameters must be set to properly evaluate blood flows with phase-contrast techniques, we developed an MRI-compatible hydrodynamic phantom to simulate different physiological blood flows. The phantom included a programmable hydraulic pump connected to a series of pipes immersed in a solution mimicking human soft tissues, with a blood-mimicking fluid flowing in the pipes. The pump is able to shape and control the flow by driving a piston through a dedicated software. Periodic waveforms are used as input to the pump to move the fluid into the pipes, with synchronization of the MRI sequences to the flow waveforms. A dedicated software is used to extract and analyze flow data from magnitude and phase images. The match between the nominal and the measured flows was assessed, and the scope of phantom variables useful for a reliable calibration of an MRI system was accordingly defined. Results showed that the NO-HYPE phantom is a valuable tool for the assessment of MRI scanners and sequence design for the MR evaluation of blood flows. Graphical abstract
29
Wu, Yi-Wei, Amit Karandikar, Julian PN Goh, and Tiong Yong Tan. "Imaging Features Differentiating Vestibular Ganglion from Intracanalicular Schwannoma on Single-Sequence Non-Contrast Magnetic Resonance Imaging Study." Annals of the Academy of Medicine, Singapore 49, no. 2 (February 29, 2020): 65–71. http://dx.doi.org/10.47102/annals-acadmedsg.2019156.
Full textAbstract:
Introduction: This study aimed to identify imaging features on single-sequence noncontrast magnetic resonance imaging (MRI) that differentiate the vestibular ganglion from small intracanalicular schwannomas. Materials and Methods: Ninety patients (42 men and 48 women; age: 24‒87 years old) with 102 internal auditory canal (IAC) nodules (59 vestibular ganglia and 43 intracanalicular schwannoma) who underwent both singlesequence T2-weighted (T2W) non-contrast enhanced MRI studies and contrast-enhanced T1-weighted (T1W) MRI studies between May 2012 and April 2017 were evaluated. The length, width, distance to the IAC fundus and length/width ratios for all lesions were obtained and compared among groups. Diagnostic performance and cutoff values of the parameters were evaluated with receiver operating characteristics curve analysis. Area under the curve (AUC) value was calculated. Results: Vestibular ganglia have significantly smaller lengths and widths compared to intracanalicular vestibular schwannomas (1.7 ± 0.4 mm and 1.0 ± 0.2 mm versus 5.6 ± 3.0 mm and 3.7 ± 1.5 mm). They are more fusiform in shape compared to vestibular schwannomas (length/width ratio: 1.8 ± 0.4 versus 1.5 ± 0.4). The lesion width demonstrated the highest diagnostic performance (AUC: 0.998). Using a cutoff width of <1.3 mm, the sensitivity, specificity and overall accuracy for diagnosing vestibular ganglia were 97% (57/59), 100% (43/43) and 98% (100/102), respectively. Conclusion: Vestibular ganglia may mimic intracanalicular vestibular schwannomas on a single-sequence T2W MRI. However, a fusiform shape and width <1.3 mm increases confidence in the diagnosis of ganglia. Identifying the vestibular ganglion on single-sequence T2W MRI studies may obviate the need for a contrast-enhanced MRI, reducing the risks of contrast administration, additional scanning time and cost. Key words: Acoustic neuroma, Internal auditory canal, Vestibulocochlear nerve
30
Zakharova, Anna V., Victoria V. Prits, and Alexander V. Pozdnyakov. "Quantitative assessment of regional pulmonary perfusion using three-dimensional ultrafast dynamic contrast-enhanced magnetic resonance imaging: pilot study results in 10 patients." Pediatrician (St. Petersburg) 12, no. 6 (April 18, 2022): 15–26. http://dx.doi.org/10.17816/ped12615-26.
Full textAbstract:
Background. Currently there is a high demand in reliable noninvasive diagnostic technique assessing the physiological parameters of the lungs. We are exploring the three-dimensional ultrafast MRI sequence as a novel diagnostic modality allowing the assessment of regional quantitative perfusion parameters in pulmonary tissue.
Aim. To assess regional differences in quantitative pulmonary perfusion parameters in 10 volunteers with no evidence of interstitial lung disease by computed tomography, clinical, and laboratory data.
Materials and methods. 10 volunteers with no signs of interstitial lung disease were examined by three-dimensional ultrafast dynamic contrast-enhanced MR imaging using 3D T1-weighted images. The values of pulmonary blood flow (PBF), mean transit time (MTT), and pulmonary blood volume (PBV) for the targeted regions of interest were calculated based on the dynamic image series. For calculations, arterial input function (AIF) was used, as well as the time-intensity curves.
Results. The values of PBF, MTT, and PBV showed statistically significant differences between central and peripheral sections of lungs. Provided model can be implemented for quantitative assessment of regional pulmonary perfusion allows it to be used to determine the reliability of PBF, MTT and PBV values.
Conclusions. Three-dimensional ultrafast MRI sequence is a novel diagnostic modality allowing the assessment of regional quantitative pulmonary perfusion parameters in pulmonary tissue, regardless of physiological features of blood supply mechanisms in different lung regions.
31
Niu, Junlong, Xiansheng Qin, Jing Bai, and Haiyan Li. "Reconstruction and optimization of the 3D geometric anatomy structure model for subject-specific human knee joint based on CT and MRI images." Technology and Health Care 29 (March 25, 2021): 221–38. http://dx.doi.org/10.3233/thc-218022.
Full textAbstract:
BACKGROUND: Nowadays, the total knee arthroplasty (TKA) technique plays an important role in surgical treatment for patients with severe knee osteoarthritis (OA). However, there are still several key issues such as promotion of osteotomy accuracy and prosthesis matching degree that need to be addressed. OBJECTIVE: It is significant to construct an accurate three-dimensional (3D) geometric anatomy structure model of subject-specific human knee joint with major bone and soft tissue structures, which greatly contributes to obtaining personalized osteotomy guide plate and suitable size of prosthesis. METHODS: Considering different soft tissue structures, magnetic resonance imaging (MRI) scanning sequences involving two-dimensional (2D) spin echo (SE) sequence T1 weighted image (T1WI) and 3D SE sequence T2 weighted image (T2WI) fat suppression (FS) are selected. A 3D modeling methodology based on computed tomography (CT) and two sets of MRI images is proposed. RESULTS: According to the proposed methods of image segmentation and 3D model registration, a novel 3D knee joint model with high accuracy is finally constructed. Furthermore, remeshing is used to optimize the established model by adjusting the relevant parameters. CONCLUSIONS: The modeling results demonstrate that reconstruction and optimization model of 3D knee joint can clearly and accurately reflect the key characteristics, including anatomical structure and geometric morphology for each component.
32
Fujianto, Slamet, Sugiyanto Sugiyanto, and Mohamad Irwan Katili. "Analisis Variasi Nilai Time Repetition (TR) dan Time Inversion (TI) terhadap Informasi Anatomi Sekuens Turbo Inversion Recovery Magnitude (TIRM) MRI Wrist Joint Dengan Menggunakan MRI 0,3 Tesla." Jurnal Imejing Diagnostik (JImeD) 2, no. 1 (January 11, 2016): 97–102. http://dx.doi.org/10.31983/jimed.v2i1.3164.
Full textAbstract:
Backgroud: The Turbo Inversion Recovery Magnitude (TIRM) pulse sequence is used to examine wrist joint, especially in the coronal plane. Main parameters of inversion recovery pulse sequence are time repetition (TR), time echo (TE) and time inversion (TI). This study aims to analyze the variation of time repetition (TR) and time inversion (TI) on anatomical information using TIRM pulse sequence on wrist joint MR imaging with 0,3 tesla.Methods: This study was a quantitave experimental study with a linear regression test. This study was conducted in Radiology Department of Banyumas hospital using twenty serial images from only one patient with 10 variation of TR (3000 ms, 3200ms, 3400 ms, 3600 ms, 3800 ms, 4000 ms, 4200 ms, 4400 ms, 4600 ms, 4800 ms) and 10 variation of TI (70 ms, 75 ms, 80 ms, 85 ms, 90 ms, 95 ms, 100 ms, 105 ms, 110 ms, 115 ms). Image assessed by only one respondent.Results: There was no significant influence of variation of TR and TI on anatomical information. Significant number was 0,240 which is bigger than p value (0,05). TR and TI variation affected just only 15,5% to anatomical information, 84,5% was influenced by other variables that unconfirmed in this study.Conclusion: There was differences of anatomical information in MRI wrist joint sequence coronal T2WI-FSE fat suppression between SPIR and SPAIR with a significance level of p value 0.001 (p 0.05). SPAIR is the method which is clearer to show the anatomical information of wrist joint.
33
Baltzer, Pascal, Ritse M. Mann, Mami Iima, Eric E. Sigmund, Paola Clauser, Fiona J. Gilbert, Laura Martincich, et al. "Diffusion-weighted imaging of the breast—a consensus and mission statement from the EUSOBI International Breast Diffusion-Weighted Imaging working group." European Radiology 30, no. 3 (November 30, 2019): 1436–50. http://dx.doi.org/10.1007/s00330-019-06510-3.
Full textAbstract:
Abstract The European Society of Breast Radiology (EUSOBI) established an International Breast DWI working group. The working group consists of clinical breast MRI experts, MRI physicists, and representatives from large vendors of MRI equipment, invited based upon proven expertise in breast MRI and/or in particular breast DWI, representing 25 sites from 16 countries. The aims of the working group are (a) to promote the use of breast DWI into clinical practice by issuing consensus statements and initiate collaborative research where appropriate; (b) to define necessary standards and provide practical guidance for clinical application of breast DWI; (c) to develop a standardized and translatable multisite multivendor quality assurance protocol, especially for multisite research studies; (d) to find consensus on optimal methods for image processing/analysis, visualization, and interpretation; and (e) to work collaboratively with system vendors to improve breast DWI sequences. First consensus recommendations, presented in this paper, include acquisition parameters for standard breast DWI sequences including specifications of b values, fat saturation, spatial resolution, and repetition and echo times. To describe lesions in an objective way, levels of diffusion restriction/hindrance in the breast have been defined based on the published literature on breast DWI. The use of a small ROI placed on the darkest part of the lesion on the ADC map, avoiding necrotic, noisy or non-enhancing lesion voxels is currently recommended. The working group emphasizes the need for standardization and quality assurance before ADC thresholds are applied. The working group encourages further research in advanced diffusion techniques and tailored DWI strategies for specific indications. Key Points • The working group considers breast DWI an essential part of a multiparametric breast MRI protocol and encourages its use. • Basic requirements for routine clinical application of breast DWI are provided, including recommendations on b values, fat saturation, spatial resolution, and other sequence parameters. • Diffusion levels in breast lesions are defined based on meta-analysis data and methods to obtain a reliable ADC value are detailed.
34
Soldati, Enrico, Lucas Escoffier, Sophie Gabriel, Augustin C. Ogier, Christophe Chagnaud, Jean P. Mattei, Serge Cammilleri, David Bendahan, and Sandrine Guis. "Assessment of in vivo bone microarchitecture changes in an anti-TNFα treated psoriatic arthritic patient." PLOS ONE 16, no. 5 (May 19, 2021): e0251788. http://dx.doi.org/10.1371/journal.pone.0251788.
Full textAbstract:
Objective Psoriatic arthritis (PsA) is an inflammatory rheumatic disease, mediated in part by TNFα and associated with bone loss. Anti-TNFα treatment should inhibit this phenomenon and reduce the systemic bone loss. Ultra-high field MRI (UHF MRI) may be used to quantify bone microarchitecture (BM) in-vivo. In this study, we quantified BM using UHF MRI in a PsA patient and followed up the changes related to anti-TNFα treatment. Subjects and methods A non-treated PsA patient with knee arthritis and 7 gender-matched controls were scanned using a gradient re-echo sequence at UHF MRI. After a year of Adalimumab treatment, the patient underwent a second UHF MRI. A PET-FNa imaging was performed before and after treatment to identify and localize the abnormal metabolic areas. BM was characterized using typical morphological parameters quantified in 32 regions of interest (ROIs) located in the patella, proximal tibia, and distal femur. Results Before treatment, the BM parameters were statistically different from controls in 24/32 ROIs with differences reaching up to 38%. After treatment, BM parameters were normalized for 15 out of 24 ROIs. The hypermetabolic areas disclosed by PET-FNa before the treatment partly resumed after the treatment. Conclusion Thanks to UHF MRI, we quantified in vivo BM anomalies in a PsA patient and we illustrated a major reversion after one year of treatment. Moreover, BM results highlighted that the abnormalities were not only localized in hypermetabolic regions identified by PET-FNa, suggesting that the bone loss was global and not related to inflammation.
35
Khodarahmi, Iman, Mathias Nittka, and Jan Fritz. "Leaps in Technology: Advanced MR Imaging after Total Hip Arthroplasty." Seminars in Musculoskeletal Radiology 21, no. 05 (October 12, 2017): 604–15. http://dx.doi.org/10.1055/s-0037-1606135.
Full textAbstract:
AbstractThe vast majority of the metal-related artifacts in magnetic resonance imaging (MRI) arise from B0 inhomogeneity. These artifacts include failed fat suppression, signal loss, signal pileup, and image distortions. Metal artifact reduction sequence MRI has been used to mitigate these artifacts via optimization of the scan parameters and exploiting new techniques such as fully phase-encoded imaging and multispectral imaging including multi-acquisition variable-resonance image combination and slice encoding for metal artifact correction. Applicability of MRI in the vicinity of metal implants has been revolutionized by these new techniques at the expense of longer acquisition times. To reach clinically viable scan times, these novel techniques have been successfully coupled with various acceleration paradigms such as parallel imaging and compressed sensing.
36
Deene, Yves De, and Morgan Wheatley. "Real time 4D Radiation Gel Dosimetry on the Australian MRI-Linac." Journal of Physics: Conference Series 2167, no. 1 (January 1, 2022): 012029. http://dx.doi.org/10.1088/1742-6596/2167/1/012029.
Full textAbstract:
Abstract 4D radiation dosimetry using a highly radiation-sensitive polymer gel dosimeter with real-time quantitative MRI readout is presented as a technique to acquire the accumulated radiation dose distribution during image guided radiotherapy (IGRT) on an MRI-Linac. Optimized T2 weighted TSE scans are converted into quantitative ΔR2 maps and subsequently to radiation dose maps. The potential of real-time 4D radiation dosimetry in a theragnostic MRI-Linac is demonstrated in test tubes, for a square beam in a cylindrical gel phantom, for a simple step-and-shoot irradiation in a head phantom and a dynamic arc treatment on a cylindrical gel phantom using a rotating couch. The optimal sequence parameters for maximal dose resolution in the dynamic MRI acquisition will be presented and the trade off between MRI scanning speed and dose resolution will be discussed. A further improvement in temporal resolution using a keyhole imaging approach is the focus of future research.
37
Wahid, Hiba M. Abdul, Ammar M. Al-Mosawe, Tara F. Kareem, Anas K. Awn, and Qusay T. Nayyef. "The Value of Diffusion Weighted MRI in the Detection and Localization of Prostate Cancer among a Sample of Iraqi Patients." AL-Kindy College Medical Journal 16, no. 2 (December 30, 2020): 45–50. http://dx.doi.org/10.47723/kcmj.v16i2.268.
Full textAbstract:
Background: Prostatic adenocarcinoma is the most widely recognized malignancy in men and the second cause of cancer-related mortality encountered in male patients after lung cancer.
Aim of the study: To assess the diagnostic value of diffusion weighted imaging (DWI) and its quantitative measurement, apparent diffusion coefficient (ADC), in the identification and localization of prostatic cancer compared with T2 weighted image sequence (T2WI).
Type of the study: a prospective analytic study
Patients and methods: forty-one male patients with suspected prostatic cancer were examined by pelvic MRI at the MRI department of the Oncology Teaching Hospital/Medical City in Baghdad from September 2017 to September 2018. Thin sections axial T2 and DWI sequences were performed for each patient. Two patients were excluded from the study due to poor image quality (motion artefact). Regions with hypointense signal on T2WI and/or restricted lesion in DWI were determined. The ADC values were measured and the results were registered and sent for biopsy correlation. The sensitivity, specifity, accuracy and other parameters were calculated for T2WI and DWI.
Results: The sensitivity and specifity of T2WI in the detection of prostate cancer was about 76.6% and 77% respectively. These improved to 96% and 88.8% by performing the DWI and measuring the ADC value. The mean ADC value was greatly lower in prostatic cancer (about 650x 10-6 mm2 /s) than in normal prostate parenchyma (about 1250 x10-6 mm2 /s) with significant difference between them (p value about 0.04)
Conclusion: In practice, using diffusion weighted MRI sequence and its ADC quantitative measurement greatly increases tumor detection in patients suspicious to have prostatic cancer and should be routinely used when doing pelvic MRI for patients with high clinical suspicion.
38
Algin, Oktay, Murat Ucar, Evrim Ozmen, Alp Ozgun Borcek, Pinar Ozisik, Gokhan Ocakoglu, and E. Turgut Tali. "Assessment of third ventriculostomy patency with the 3D-SPACE technique: a preliminary multicenter research study." Journal of Neurosurgery 122, no. 6 (June 2015): 1347–55. http://dx.doi.org/10.3171/2014.10.jns14298.
Full textAbstract:
OBJECT The goal of this study was to determine the value of the 3D sampling perfection with application-optimized contrasts using different flip-angle evolutions (3D-SPACE) technique in the evaluation of endoscopic third ventriculostomy (ETV) patency. METHODS Twenty-six patients with ETV were examined using 3-T MRI units. Sagittal-plane 3D-SPACE with variant flip-angle mode, 3D T1-weighted (T1W), and 3D heavily T2-weighted (T2W) images were obtained with isotropic voxel sizes. Also, sagittal-axial plane phase-contrast cine (PC)-MR images were obtained. The following findings were evaluated: diameters of stoma and third ventricle, flow-void sign on 3D-SPACE and PC-MR images, integrity of the third ventricle on heavily T2W images, and quantitative PC-MRI parameters of the stoma. Obtained sequences were evaluated singly, in combination with one another, and all together. RESULTS The mean area, flow, and velocity values measured at the level of stoma in patients with patent stoma were significantly higher than those measured in patients with closed stoma (p < 0.05). There was significant correlation among PC-MRI, 3D-SPACE, and 3D heavily T2W techniques regarding assessment of ETV patency (p < 0.001). The 3D-SPACE technique provided the lowest rate of ambiguous results. CONCLUSIONS The 3D-SPACE technique seems to be the most efficient one for determination of ETV patency. The authors suggest the use of 3D-SPACE as a stand-alone first-line sequence in addition to routine brain MRI protocols in assessing patients with ETV, thereby decreasing scan time and reserving the use of a combination of additional sequences such as PC-MRI and 3D heavily T2W images in suspicious or complex cases.
39
Dissaux, Brieg, Doria Mazouz Fatmi, Julien Ognard, Bastien Allard, Nathalie Keromnes, Amina Latreche, Amandine Lepeuve, et al. "Radiotherapy Target Volume Definition in Newly Diagnosed High-Grade Glioma Using 18F-FET PET Imaging and Multiparametric MRI: An Inter Observer Agreement Study." Tomography 8, no. 4 (August 16, 2022): 2030–41. http://dx.doi.org/10.3390/tomography8040170.
Full textAbstract:
Background: The aim of this prospective monocentric study was to assess the inter-observer agreement for tumor volume delineations by multiparametric MRI and 18-F-FET-PET/CT in newly diagnosed, untreated high-grade glioma (HGG) patients. Methods: Thirty patients HGG underwent O-(2-[18F]-fluoroethyl)-l-tyrosine(18F-FET) positron emission tomography (PET), and multiparametric MRI with computation of rCBV map and K2 map. Three nuclear physicians and three radiologists with different levels of experience delineated the 18-F-FET-PET/CT and 6 MRI sequences, respectively. Spatial similarity (Dice and Jaccard: DSC and JSC) and overlap (Overlap: OV) coefficients were calculated between the readers for each sequence. Results: DSC, JSC, and OV were high for 18F-FET PET/CT, T1-GD, and T2-FLAIR (>0.67). The Spearman correlation coefficient between readers was ≥0.6 for these sequences. Cross-comparison of similarity and overlap parameters showed significant differences for DSC and JSC between 18F-FET PET/CT and T2-FLAIR and for JSC between 18F-FET PET/CT and T1-GD with higher values for 18F-FET PET/CT. No significant difference was found between T1-GD and T2-FLAIR. rCBV, K2, b1000, and ADC showed correlation coefficients between readers <0.6. Conclusion: The interobserver agreements for tumor volume delineations were high for 18-F-FET-PET/CT, T1-GD, and T2-FLAIR. The DWI (b1000, ADC), rCBV, and K2-based sequences, as performed, did not seem sufficiently reproducible to be used in daily practice.
40
Kim, Young Ro, Mark D. Savellano, Ralph Weissleder, and Alexei Bogdanov. "Steady-state and Dynamic Contrast MR Imaging of Human Prostate Cancer Xenograft Tumors: A Comparative Study." Technology in Cancer Research & Treatment 1, no. 6 (December 2002): 489–95. http://dx.doi.org/10.1177/153303460200100609.
Full textAbstract:
Understanding tumor vascular physiology is critically important for developing non-invasive, molecularly targeted diagnostic agents and therapies. In this study, using three different human prostate cancer xenografts (MDA PCa 2b, PC3, and LnCap), structural and physiological parameters of neoplastic vasculature and interstitum were explored with a widely available magnetic resonance imaging (MRI) pulse sequence (3D SPGR: spoiled gradient echo). Using dual injection technique employing two T1 contrast agents of different molecular masses (Weissleder, R., Cheng, H. C., Marecos, E., Kwong, K. K., Bogdanov, A., Jr. Eur. J. Cancer 34, 1448–1454 (1998)), steady state (SS) MRI measurements and dynamic contrast agent enhancement (DCE) MRI measurements were simultaneously acquired and analyzed using a two-compartment model for calculating parameters reflecting tumoral architecture and physiology. In particular, interstitial volume and vascular permeability were independently quantified using these two different MRI techniques. Relative vascular water exchange rate, calculated by the flip angle (FA) dependence of measured blood volume using SS technique, and vascular permeability of contrast agent, extrapolated from DCE MRI, were compared. It was found that the SS and DCE techniques were comparable and yielded similar qualitative results for extravascular compartment (interstitial volume). However, the permeability (water exchange rate and contrast agent vascular permeability) values were in disagreement. The results of MR studies are important for interpreting optical imaging results obtained using long-circulating of tumor-associated enzymatic activity.
41
Krüchten, Ricarda von, Susanne Rospleszcz, Roberto Lorbeer, Dunja Hasic, Annette Peters, Fabian Bamberg, Holger Schulz, Stefan Karrasch, and Christopher L. Schlett. "Whole-Body MRI-Derived Adipose Tissue Characterization and Relationship to Pulmonary Function Impairment." Tomography 8, no. 2 (February 27, 2022): 560–69. http://dx.doi.org/10.3390/tomography8020046.
Full textAbstract:
Background: Specification of adipose tissues by whole-body magnetic resonance imaging (MRI) was performed and related to pulmonary function parameters in a population-based cohort. Methods: 203 study participants underwent whole-body MRI and pulmonary function tests as part of the KORA (Cooperative Health Research in the Augsburg Region) MRI study. Both visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were derived from the T1-Dixon sequence, and hepatic adipose tissue from the proton density fat fraction (PDFFhepatic). Associations between adipose tissue parameters and spirometric indices such as forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1) and Tiffeneau-index (FEV1/FVC) were examined using multivariate linear regression analysis excluding cofounding effects of other clinical parameters. Results: VAT (β = −0.13, p = 0.03) and SAT (β = −0.26, p < 0.001), but not PDFFhepatic were inversely associated with FEV1, while VAT (β = −0.27, p < 0.001), SAT (β = −0.41, p < 0.001), and PDFFhepatic (β = −0.17, p = 0.002) were inversely associated with FVC. PDFFhepatic was directly associated with the Tiffeneau index (β = 2.46, p < 0.001). Conclusions: In the adjusted linear regression model, VAT was inversely associated with all measured spirometric parameters, while PDFFhepatic revealed the strongest association with the Tiffeneau index. Non-invasive adipose tissue quantification measurements might serve as novel biomarkers for respiratory impairment.
42
Voelkl, Jakob G. J., Bernhard J. Haubner, Christian Kremser, Agnes Mayr, Gert Klug, Alexander Loizides, Silvana Müller, Otmar Pachinger, Michael Schocke, and Bernhard Metzler. "Cardiac Imaging Using Clinical 1.5 T MRI Scanners in a Murine Ischemia/Reperfusion Model." Journal of Biomedicine and Biotechnology 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/185683.
Full textAbstract:
To perform cardiac imaging in mice without having to invest in expensive dedicated equipment, we adapted a clinical 1.5 Tesla (T) magnetic resonance imaging (MRI) scanner for use in a murine ischemia/reperfusion model. Phase-sensitive inversion recovery (PSIR) sequence facilitated the determination of infarct sizesin vivoby late gadolinium enhancement. Results were compared to histological infarct areas in mice after ischemia/reperfusion procedure with a good correlation (, ). In addition, fractional area change (FAC) was assessed with single slice cine MRI and was matched to infarct size () and fractional shortening (FS) measured with echocardiography (); both . Here, we demonstrate the use of clinical 1.5 MRI scanners as a feasible method for basic phenotyping in mice. These widely available scanners are capable of investigatingin vivoinfarct dimensions as well as assessment of cardiac functional parameters in mice with reasonable throughput.
43
Güttsches, Anne-Katrin, Robert Rehmann, Anja Schreiner, Marlena Rohm, Johannes Forsting, Martijn Froeling, Martin Tegenthoff, Matthias Vorgerd, and Lara Schlaffke. "Quantitative Muscle-MRI Correlates with Histopathology in Skeletal Muscle Biopsies." Journal of Neuromuscular Diseases 8, no. 4 (July 30, 2021): 669–78. http://dx.doi.org/10.3233/jnd-210641.
Full textAbstract:
Background: Skeletal muscle biopsy is one of the gold standards in the diagnostic workup of muscle disorders. By histopathologic analysis, characteristic features like inflammatory cellular infiltrations, fat and collagen replacement of muscle tissue or structural defects of the myofibers can be detected. In the past years, novel quantitative MRI (qMRI) techniques have been developed to quantify tissue parameters, thus providing a non-invasive diagnostic tool in several myopathies. Objective: This proof-of-principle study was performed to validate the qMRI-techniques to skeletal muscle biopsy results. Methods: Ten patients who underwent skeletal muscle biopsy for diagnostic purposes were examined by qMRI. Fat fraction, water T2-time and diffusion parameters were measured in the muscle from which the biopsy was taken. The proportion of fat tissue, the severity of degenerative and inflammatory parameters and the amount of type 1- and type 2- muscle fibers were determined in all biopsy samples. The qMRI-data were then correlated to the histopathological findings. Results: The amount of fat tissue in skeletal muscle biopsy correlated significantly with the fat fraction derived from the Dixon sequence. The water T2-time, a parameter for tissue edema, correlated with the amount of vacuolar changes of myofibers and endomysial macrophages in the histopathologic analysis. No significant correlations were found for diffusion parameters. Conclusion: In this proof-of-principle study, qMRI techniques were related to characteristic histopathologic features in neuromuscular disorders. The study provides the basis for further development of qMRI methods in the follow-up of patients with neuromuscular disorders, especially in the context of emerging treatment strategies.
44
Svecic, Andrei, Rihab Mansour, An Tang, and Samuel Kadoury. "Prediction of post transarterial chemoembolization MR images of hepatocellular carcinoma using spatio-temporal graph convolutional networks." PLOS ONE 16, no. 12 (December 7, 2021): e0259692. http://dx.doi.org/10.1371/journal.pone.0259692.
Full textAbstract:
Magnetic resonance imaging (MRI) plays a critical role in the planning and monitoring of hepatocellular carcinomas (HCC) treated with locoregional therapies, in order to assess disease progression or recurrence. Dynamic contrast-enhanced (DCE)-MRI sequences offer temporal data on tumor enhancement characteristics which has strong prognostic value. Yet, predicting follow-up DCE-MR images from which tumor enhancement and viability can be measured, before treatment of HCC actually begins, remains an unsolved problem given the complexity of spatial and temporal information. We propose an approach to predict future DCE-MRI examinations following transarterial chemoembolization (TACE) by learning the spatio-temporal features related to HCC response from pre-TACE images. A novel Spatial-Temporal Discriminant Graph Neural Network (STDGNN) based on graph convolutional networks is presented. First, embeddings of viable, equivocal and non-viable HCCs are separated within a joint low-dimensional latent space, which is created using a discriminant neural network representing tumor-specific features. Spatial tumoral features from independent MRI volumes are then extracted with a structural branch, while dynamic features are extracted from the multi-phase sequence with a separate temporal branch. The model extracts spatio-temporal features by a joint minimization of the network branches. At testing, a pre-TACE diagnostic DCE-MRI is embedded on the discriminant spatio-temporal latent space, which is then translated to the follow-up domain space, thus allowing to predict the post-TACE DCE-MRI describing HCC treatment response. A dataset of 366 HCC’s from liver cancer patients was used to train and test the model using DCE-MRI examinations with associated pathological outcomes, with the spatio-temporal framework yielding 93.5% classification accuracy in response identification, and generating follow-up images yielding insignificant differences in perfusion parameters compared to ground-truth post-TACE examinations.
45
Krüchten, Ricarda von, Roberto Lorbeer, Susanne Rospleszcz, Corinna Storz, Esther Askani, Charlotte Kulka, Wolfgang Rathmann, et al. "Serum insulin is associated with right ventricle function parameters and lung volumes in subjects free of cardiovascular disease." European Journal of Endocrinology 184, no. 2 (February 2021): 289–98. http://dx.doi.org/10.1530/eje-20-1010.
Full textAbstract:
Background Diabetes mellitus is an established risk factor for cardiovascular diseases. Even impaired levels of glucose and insulin might harm organ function prior to diabetes onset. Whether serum glucose or insulin plays a direct role in cardiac dysfunction or lung volume reduction remains unclear. The aim was to investigate the relationship between glucose and insulin with the right ventricle and lung volumes within KORA-MRI FF4 study. Methods From the KORA-MRI FF4 cohort study 337 subjects (mean age 55.7 ± 9.1 years; 43% women) underwent a whole-body 3T MRI scan. Cardiac parameters derived from a cine-steady-state free precession sequence using cvi42. MRI-based lung volumes derived semi-automatically using an in-house algorithm. Fasting serum glucose, fasting insulin levels, and HOMA index were calculated in all study subjects. Linear regression analyses were performed to assess the relationships between glucose and insulin levels with right ventricle volumes and lung volumes adjusted for age, sex, BMI, and cardiovascular risk factors. Results In univariate and multivariate-adjusted models, high serum insulin was inversely associated with end-diastolic volume (β = −12.43, P < 0.001), end-systolic volume (β = −7.12, P < 0.001), stroke volume (β = −5.32, P < 0.001), but not with ejection fraction. The association remained significant after additional adjustment for lung volumes. Similarly, serum insulin was inversely associated with lung volume (β = −0.15, P = 0.04). Sensitivity analysis confirmed results after excluding subjects with known diabetes. Conclusions Serum insulin was inversely associated with right ventricle function and lung volumes in subjects from the general population free of cardiovascular disease, suggesting that increased insulin levels may contribute to subclinical cardiopulmonary circulation impairment.
46
Yip, Vincent S., Brendan Colins, Mei Y. Koay, Joseph Tang, Hulya Wieshmann, Stephen W. Fenwick, Graeme John Poston, and Hassan Zakria Malik. "Cost-effectiveness and optimal diagnostic sequence of CT, MRI, and PET-CT in the management of colorectal liver metastases." Journal of Clinical Oncology 31, no. 15_suppl (May 20, 2013): 4132. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.4132.
Full textAbstract:
4132 Background: CT, PET-CT and MRI play a role in the decision making process in managing colorectal liver metastases (CRLM). This study aimed to determine the optimal sequence of these investigations in order to reduce the rate of futile laparotomy and improve cost effectiveness of treatment. Methods: All patients referred to our specialist multidisciplinary team (sMDT) with CRLM were reviewed to investigate specific reason(s) for not offering potentially curative surgery. Clinical parameters were recorded for analysis. Three hypothetical scenarios were derived for cost-effectiveness analyses: 1) “up-front” with all imaging prior to sMDT, 2) “sequential”, with individual imaging following each sMDT, and 3) “hybrid” with PET-CT and MRI after review of the initial CT scan. Results: 644 consecutive patients were reviewed. Following assessment of initial CT, 165 patients (26%) were referred for palliative chemotherapy. After further evaluation by PET +/- MRI, 307 patients proceeded for potentially curative resection. Of those excluded from surgery, 48% were following PET-CT. Median overall survival (OS) for the resection and palliative groups were 46 and 14 months respectively (p<0.001). Futile laparotomy rate was 5.5%.The optimum strategy of lowest average time to decision, and lowest average cost is the hybrid model. Cost-utility analyses demonstrated a saving of approx. £319 (USD$ 515) per patient compared to the other 2 models. Conclusions: Decision making regarding further imaging after initial CT scan for CRLM should be performed at the sMDT to minimise delays and maximise efficiency of resources allocation. Triple assessment with CT, PET and MRI and sMDT decision process may reduce risk of futile laparotomy. A hybrid model using PET and MRI following a sMDT discussion of the initial CT provides the most cost effective algorithm for the management of CRLM.
47
Ruckli, Adrian C., Andreas K. Nanavati, Malin K. Meier, Till D. Lerch, Simon D. Steppacher, Sébastian Vuilleumier, Adam Boschung, et al. "A Deep Learning Method for Quantification of Femoral Head Necrosis Based on Routine Hip MRI for Improved Surgical Decision Making." Journal of Personalized Medicine 13, no. 1 (January 12, 2023): 153. http://dx.doi.org/10.3390/jpm13010153.
Full textAbstract:
(1) Background: To evaluate the performance of a deep learning model to automatically segment femoral head necrosis (FHN) based on a standard 2D MRI sequence compared to manual segmentations for 3D quantification of FHN. (2) Methods: Twenty-six patients (thirty hips) with avascular necrosis underwent preoperative MR arthrography including a coronal 2D PD-w sequence and a 3D T1 VIBE sequence. Manual ground truth segmentations of the necrotic and unaffected bone were then performed by an expert reader to train a self-configuring nnU-Net model . Testing of the network performance was performed using a 5-fold cross-validation and Dice coefficients were calculated. In addition, performance across the three segmentations were compared using six parameters: volume of necrosis, volume of unaffected bone, percent of necrotic bone volume, surface of necrotic bone, unaffected femoral head surface, and percent of necrotic femoral head surface area. (3) Results: Comparison between the manual 3D and manual 2D segmentations as well as 2D with the automatic model yielded significant, strong correlations (Rp > 0.9) across all six parameters of necrosis. Dice coefficients between manual- and automated 2D segmentations of necrotic- and unaffected bone were 75 ± 15% and 91 ± 5%, respectively. None of the six parameters of FHN differed between the manual and automated 2D segmentations and showed strong correlations (Rp > 0.9). Necrotic volume and surface area showed significant differences (all p < 0.05) between early and advanced ARCO grading as opposed to the modified Kerboul angle, which was comparable between both groups (p > 0.05). (4) Conclusions: Our deep learning model to automatically segment femoral necrosis based on a routine hip MRI was highly accurate. Coupled with improved quantification for volume and surface area, as opposed to 2D angles, staging and course of treatment can become better tailored to patients with varying degrees of AVN.
48
Arief Apriliani, Karina Sandra, Sri Andreani Utomo, Muhaimin, and Lailatul Muqmiroh. "IMAGE COMPARISON ON T2 QTSE LUMBAL EXAMINATION USING GRAPPA TECHNIQUE WITH AND WITHOUT MAGNETIZATION TRANSFER CONTRAST IN DEGENERATIVE DISC DISEASE CASE." Journal of Vocational Health Studies 6, no. 1 (July 30, 2022): 9–16. http://dx.doi.org/10.20473/jvhs.v6.i1.2022.9-16.
Full textAbstract:
Background: The description of Degenerative Disc Disease in MRI lumbar FSE sequence T2WI is seen as a decrease in signal intensity. Patients with cases of Degenerative Disc Disease experience severe low back pain and cannot lie supine for a long time, while MRI is very sensitive to movement. GRAPPA is a parallel imaging technique that can produce images with a fast scan time but is followed by a decreased Signal to Noise Ratio SNR value. This technique needs to be followed by setting other parameters to produce an optimal image, namely by applying Magnetization Transfer Contrast (MTC). Purpose: To compare the quality of image results on lumbar MRI examination of the sagittal T2 qTSE sequence in the case of Degenerative Disc Disease with and without MTC activation. Method: This research was conducted at the dr. Soedono Madiun from August to September 2020. A sample of 16 patients who met the inclusion criteria was taken during the study. The GRAPPA and GRAPPA+MTC technique imagery results on each sample were assessed for the image quality quantitatively based on the SNR and CNR values. Result: Based on the SNR value, the GRAPPA technique and MTC activation have a higher mean than the GRAPPA technique alone. Likewise, with the CNR value, the GRAPPA technique and MTC activation have a higher average than the GRAPPA technique alone. Conclusion: The GRAPPA technique and MTC activation can be applied in Lumbar MRI examination with cases of Degenerative Disc Disease, especially in uncooperative patients.
49
Staal, Alexander H. J., Andor Veltien, Mangala Srinivas, and Tom W. J. Scheenen. "19F MRI Imaging Strategies to Reduce Isoflurane Artifacts in In Vivo Images." Molecular Imaging and Biology 24, no. 1 (October 20, 2021): 71–81. http://dx.doi.org/10.1007/s11307-021-01653-6.
Full textAbstract:
Abstract Purpose Isoflurane (ISO) is the most commonly used preclinical inhalation anesthetic. This is a problem in 19F MRI of fluorine contrast agents, as ISO signals cause artifacts that interfere with unambiguous image interpretation and quantification; the two most attractive properties of heteronuclear MRI. We aimed to avoid these artifacts using MRI strategies that can be applied by any pre-clinical researcher. Procedures Three strategies to avoid ISO chemical shift displacement artifacts (CSDA) in 19F MRI are described and demonstrated with measurements of 19F-containing agents in phantoms and in vivo (n = 3 for all strategies). The success of these strategies is compared to a standard Rapid Acquisition with Relaxation Enhancement (RARE) sequence, with phantom and in vivo validation. ISO artifacts can successfully be avoided by (1) shifting them outside the region of interest using a narrow signal acquisition bandwidth, (2) suppression of ISO by planning a frequency-selective suppression pulse before signal acquisition or by (3) preventing ISO excitation with a 3D sequence with a narrow excitation bandwidth. Results All three strategies result in complete ISO signal avoidance (p < 0.0001 for all methods). Using a narrow acquisition bandwidth can result in loss of signal to noise ratio and distortion of the image, and a frequency-selective suppression pulse can be incomplete when B1-inhomogeneities are present. Preventing ISO excitation with a narrow excitation pulse in a 3D sequence yields the most robust results (relative SNR 151 ± 28% compared to 2D multislice methods, p = 0.006). Conclusion We optimized three easily implementable methods to avoid ISO signal artifacts and validated their performance in phantoms and in vivo. We make recommendation on the parameters that pre-clinical studies should report in their method section to make the used approach insightful.
50
von Krüchten, Ricarda, Roberto Lorbeer, Annette Peters, Fabian Bamberg, Christopher L. Schlett, and Blerim Mujaj. "Association between Large Arteries Diameter and Heart Function in Subjects Free of Cardiovascular Diseases." Journal of Personalized Medicine 12, no. 6 (May 28, 2022): 889. http://dx.doi.org/10.3390/jpm12060889.
Full textAbstract:
To investigate the association between Aorta (Ao), pulmonary artery (PA) diameters and the PA/Ao ratio with right (RV) and left ventricle (LV) volumetric properties in subjects free of cardiovascular diseases. In the KORA-MRI study, 339 subjects (mean age 56.3 ± 9.1 years; 43.7% female) underwent whole-body 3T-MRI. Ao and PA were measured on DIXON sequences. Cvi42 quantified cardiac functional parameters from a SSFP sequence. The relationship between ascending (AAo), and descending aorta (DAo), as well as PA diameters, and RV and LV function were assessed using linear regression models adjusted for age, sex, and cardiovascular risk factors. AAo and DAo diameter were associated with LV end-diastolic volume (β = 4.52, p = 0.015; ß = 7.1, p ≤ 0.001), LV end-systolic volume (β = 2.37, p = 0.031; ß = 3.66, p = 0.002), while DAo associated with RV end-diastolic volume (β = 6.45, p = 0.006) and RV end-systolic volume (β = 3.9, p = 0.011). PA diameter was associated with LV end-diastolic volume (β = 4.81, p = 0.003). Interestingly, the PA/Ao ratio was only associated with RV end-diastolic and end-systolic volume (β = 4.48, p = 0.029; ß = 2.82, p = 0.037). Furthermore, we found different relationships between men and women. Ao and PA diameter were associated with LV and RV volumetric parameters in subjects free of cardiovascular diseases suggesting that ventricular volumetric performance directly relates to vascular diameter properties.