Artículos de revistas: "Registration markers"

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Dunne, James J., Thomas K. Uchida, Thor F. Besier, Scott L. Delp y Ajay Seth. "A marker registration method to improve joint angles computed by constrained inverse kinematics". PLOS ONE 16, n.º 5 (28 de mayo de 2021): e0252425. http://dx.doi.org/10.1371/journal.pone.0252425.

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Accurate computation of joint angles from optical marker data using inverse kinematics methods requires that the locations of markers on a model match the locations of experimental markers on participants. Marker registration is the process of positioning the model markers so that they match the locations of the experimental markers. Markers are typically registered using a graphical user interface (GUI), but this method is subjective and may introduce errors and uncertainty to the calculated joint angles and moments. In this investigation, we use OpenSim to isolate and quantify marker registration–based error from other sources of error by analyzing the gait of a bipedal humanoid robot for which segment geometry, mass properties, and joint angles are known. We then propose a marker registration method that is informed by the orientation of anatomical reference frames derived from surface-mounted optical markers as an alternative to user registration using a GUI. The proposed orientation registration method reduced the average root-mean-square error in both joint angles and joint moments by 67% compared to the user registration method, and eliminated variability among users. Our results show that a systematic method for marker registration that reduces subjective user input can make marker registration more accurate and repeatable.

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Kim, Tae-wan, Yeong-hwa Seo, Sang-chul Lee, Zhouwang Yang y Minho Chang. "Simultaneous registration of multiple views with markers". Computer-Aided Design 41, n.º 4 (abril de 2009): 231–39. http://dx.doi.org/10.1016/j.cad.2008.10.007.

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Jamali, Seyed H., Seyed A. Mohammadi y Behzad Sadeghzadeh. "Association mapping for morphological traits relevant to registration of barley varieties". Spanish Journal of Agricultural Research 15, n.º 4 (7 de febrero de 2018): e0704. http://dx.doi.org/10.5424/sjar/2017154-10494.

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Elucidating marker-trait associations would have fruitful implications in distinctness, uniformity, and stability (DUS) tests of new varieties required for both variety registration and granting plant breeders’ rights. As the number of new varieties with narrow genetic bases increases, the necessity for deployment of molecular markers to complement morphological DUS traits gets particular attention. We used simple sequence repeats (SSRs) and sequence related amplification polymorphisms (SRAPs) markers in association mapping of morphological traits in a collection of 143 barley landraces and advanced breeding lines. This panel represented a diverse and uniform sample in terms of both quantitative and categorical traits whilst it was structurally partitioned by number of ear rows (six- and two-rowed) and seasonal growth habit (winter and spring types) characteristics. SSRs were more powerful compared with SRAPs in separating six- and two-rowed genotypes based on both model-based Bayesian and neighbor joining clustering methods. A number of associated SSR and SRAP markers were found for 15 out of 36 DUS traits after considering Bonferroni correction through linear models (GLM and MLM) and chi-square-based tests (SA and AAT). This is also the first report of association of awn roughness and grain color with molecular markers in barley. Moreover, SSR marker BMAC0113 appeared associated with time of ear emergence (TEE), confirming previous findings. These markers could be beneficial to complement and speed up DUS testing of new varieties, as well as for improving management of barley reference collections.

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Watchman, Christopher J., Russell J. Hamilton, Baldassarre Stea y Alan J. Mignault. "PATIENT POSITIONING USING IMPLANTED GOLD MARKERS WITH THE NOVALIS BODY SYSTEM IN THE THORACIC SPINE". Neurosurgery 62, suppl_5 (1 de mayo de 2008): A62—A68. http://dx.doi.org/10.1227/01.neu.0000325938.08605.eb.

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ABSTRACT OBJECTIVE To evaluate the effectiveness of implanted gold marker registration compared with bony fusion alignment for patient positioning using the Novalis Body system. METHODS Eighteen treatment fractions of stereotactic spinal radiotherapy were analyzed for three patients who each had three implanted gold seeds placed near their spinal lesions before radiotherapy. At each treatment session, the registration was first performed using bony fusion and then verified by another bony fusion, followed by registration with implanted markers. The software reported the calculated shifts for both methods. In addition, the actual three-dimensional coordinate positions of the markers were read using PTDReader software. Implanted marker positions were analyzed for variations in individual maker coordinate displacement, interseed distances, and area transcribed by them. Measured positional differences between the two fusion methods were applied to actual treatment plans to assess the resulting dosimetric differences in the treatment plans. RESULTS Both fusion algorithms were shown to localize the patient well, within 1.5 mm, but the implanted marker fusion consistently related less deviation from the planned isocenter, by approximately 0.5 mm, than did the bony fusion. Exceptions to this localization occurred when the average interseed distances were less than 3.0 cm and resulted in the two registration methods being equivalent. Implanted spine markers were also shown to have less than 0.7 mm deviation from the planned marker coordinates, indicating no migration of the seeds. Dose distributions were found to be highly dependant on differences in fusion method, with spinal cord doses up to 350% greater with bony fusion than with implanted markers. CONCLUSION Implanted markers used with the Novalis Body system have been shown to be more effective in patient positioning than the bony fusion method in the thoracic spine.

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Woerdeman, Peter A., Peter W. A. Willems, Herke J. Noordmans, Cornelis A. F. Tulleken y Jan Willem Berkelbach van der Sprenkel. "Application accuracy in frameless image-guided neurosurgery: a comparison study of three patient-to-image registration methods". Journal of Neurosurgery 106, n.º 6 (junio de 2007): 1012–16. http://dx.doi.org/10.3171/jns.2007.106.6.1012.

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Object The aim of this study was to compare three patient-to-image registration methods in frameless stereotaxy in terms of their application accuracy (the accuracy with which the position of a target can be determined intraoperatively). In frameless stereotaxy, imaging information is transposed to the surgical field to show the spatial position of a localizer or surgical instrument. The mathematical relationship between the image volume and the surgical working space is calculated using a rigid body transformation algorithm, based on point-pair matching or surface matching. Methods Fifty patients who were scheduled to undergo a frameless image-guided neurosurgical procedure were included in the study. Prior to surgery, the patients underwent either computerized tomography (CT) scanning or magnetic resonance (MR) imaging with widely distributed adhesive fiducial markers on the scalp. An extra fiducial marker was placed on the head as a target, as near as possible to the intracranial lesion. Prior to each surgical procedure, an optical tracking system was used to perform three separate patient-to-image registration procedures, using anatomical landmarks, adhesive markers, or surface matching. Subsequent to each registration, the target registration error (TRE), defined as the Euclidean distance between the image space coordinates and world space coordinates of the target marker, was determined. Independent of target location or imaging modality, mean application accuracy (± standard deviation) was 2.49 ± 1.07 mm when using adhesive markers. Using the other two registration strategies, mean TREs were significantly larger (surface matching, 5.03 ± 2.30 mm; anatomical landmarks, 4.97 ± 2.29 mm; p < 0.001 for both). Conclusions The results of this study show that skin adhesive fiducial marker registration is the most accurate noninvasive registration method. When images from an earlier study are to be used and accuracy may be slightly compromised, anatomical landmarks and surface matching are equally accurate alternatives.

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Liao, Ai-Ho, Li-Yen Chen, Wen-Fang Cheng y Pai-Chi Li. "A Three-Dimensional Registration Method for MicroUS/MicroPET Multimodality Small-Animal Imaging". Ultrasonic Imaging 29, n.º 3 (julio de 2007): 155–66. http://dx.doi.org/10.1177/016173460702900302.

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Small-animal models are used extensively in disease research, genomics research, drug development and developmental biology. The development of noninvasive small-animal imaging techniques with adequate spatial resolution and sensitivity is therefore of prime importance. In particular, multimodality small-animal imaging can provide complementary information. This paper presents a method for registering high-frequency ultrasonic (microUS) images with small-animal positron-emission tomography (microPET) images. Registration is performed using six external multimodality markers, each being a glass bead with a diameter of 0.43–0.60 mm, with 0.1 μl of [18F]FDG placed in each marker holder. A small-animal holder is used to transfer mice between the microPET and microUS systems. Multimodality imaging was performed on C57BL/6J black mice bearing WF-3 ovary cancer cells in the second week after tumor implantation and rigid-body image registration of the six markers was also performed. The average registration error was 0.31 mm when all six markers were used and increased as the number of markers decreased. After image registration, image segmentation and fusion are performed on the tumor. Our multimodality small-animal imaging method allows structural information from microUS to be combined with functional information from microPET, with the preliminary results showing it to be an effective tool for cancer research.

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Matsumoto, Nozomu, Jaesung Hong, Hashizume Makoto y Shizuo Komune. "S203 – The STAMP Registration for Image-guided Otologic Surgery". Otolaryngology–Head and Neck Surgery 139, n.º 2_suppl (agosto de 2008): P143—P144. http://dx.doi.org/10.1016/j.otohns.2008.05.378.

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Objectives 1) Develop a less invasive but accurate enough registration strategy for otological surgical navigation. 2) Evaluate the new system in phantom study. 3) Evaluate the new system in cochlear implant surgeries. Methods A new registration method was developed for otologic surgery. Previously, the registration for accurate image-guided surgery often required invasive fiducial markers attached on patient's bone. We utilized the template of the bone surface to transfer the pre-made virtual bone-anchored markers to the patient's bone intraoperatively and eliminated the necessity for preoperative marker positioning or preoperative additional CT scan. Results We tested this Surface Template-Assisted Marker Positioning (STAMP) method using 5 temporal bone replicas, and in 5 ear surgeries (2 cochlear implants, 3 translabyrinthine acoustic neuroma surgeries) to investigate whether this method improves, or at least retains, the accuracy of image- guided surgery (IGS). The fiducial registration errors and target registration errors in the phantom study was ∼0.7 mm and ∼1.5 mm, respectively. The target registration errors in replicas were always less than 2 mm. In actual ear surgeries the fiducial registration errors were ∼0.6 mm and the target registration errors were less than 2 mm in 4 of 5 surgeries. All patients received successful cochlear implantation or tumor removal. Conclusions The new method reduced the preoperative procedures for patients but did not reduce the accuracy of the surgical navigation. Our method would be a useful IGS method in the field of otology where both accuracy and non-invasiveness are required.

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Kristin, Julia, Manuel Burggraf, Dirk Mucha, Christoph Malolepszy, Silvan Anderssohn, Joerg Schipper y Thomas Klenzner. "Automatic Registration for Navigation at the Anterior and Lateral Skull Base". Annals of Otology, Rhinology & Laryngology 128, n.º 10 (8 de mayo de 2019): 894–902. http://dx.doi.org/10.1177/0003489419849086.

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Objective: Navigation systems create a connection between imaging data and intraoperative situs, allowing the surgeon to consistently determine the location of instruments and patient anatomy during the surgical procedure. The best results regarding the target registration error (measurement uncertainty) are normally demonstrated using fiducials. This study aimed at investigating a new registration strategy for an electromagnetic navigation device. Methods: For evaluation of an electromagnetic navigation system and comparison of registration with screw markers and automatic registration, we are calculating the target registration error in the region of the paranasal sinuses/anterior and lateral skull base with the use of an electromagnetic navigation system and intraoperative digital volume tomography (cone-beam computed tomography). We carried out 10 registrations on a head model (total n = 150 measurements) and 10 registrations on 4 temporal bone specimens (total n = 160 measurements). Results: All in all, the automatic registration was easy to perform. For the models that were used, a significant difference between an automatic registration and the registration on fiducials was evident for just a limited number of screws. Furthermore, the observed differences varied in terms of the preferential registration procedure. Conclusion: The automatic registration strategy seems to be an alternative to the established methods in artificial and cadaver models of intraoperative scenarios. Using intraoperative imaging, there is an option to resort to this kind of registration as needed.

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Lente, Kornelius, Karin H. Somerlik-Fuchs, Jonas Friedrich Schiemer, Axel Heimann, Roman Ruff, Jan Baumgart, Klaus-Peter Hoffmann, Thilo B. Krüger y Werner Kneist. "Motility analysis by means of video tracked markers". Current Directions in Biomedical Engineering 4, n.º 1 (1 de septiembre de 2018): 341–44. http://dx.doi.org/10.1515/cdbme-2018-0082.

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AbstractThe motility of the gastrointestinal tract is crucial for digestive activity and dysfunction can lead to severe disease pattern. A method for analysing the motility is needed when treatment approaches shall be evaluated. Therefore markers attached to different locations on the stomach and the bowel of pigs are video tracked in this research study. The markers are designed to provide a high contrast and have an adhesive side for fixation. Above the operation field a video camera has been placed to film the markers during the procedure. To analyse the video data a special algorithm has been implemented. The algorithm requires a registration process at the beginning of each recording which allows the parallel tracking of multiple markers. After the registration the algorithm tracks the position of the marker frame by frame. Each frame is converted into a greyscale picture by adding specified colour values of each pixel. This allows emphasizing certain colours. The centre of the marker is determined by computing the horizontal and vertical centre of the marker starting at the corresponding marker position of the previous frame. After completion the data is stored as coordinates and a video with the marker position displayed for further processing. For advanced analysis the data can be synchronized with electromyography signals, for example. The marked videos show a promising tracking of the markers. However, if the algorithm loses track of a marker during a recording, it is unlikely to relocate it due to the successive processing of the frames. Nevertheless this method provides a simple and easy to use solution for movement detection of the gastrointestinal tract.

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Yamamoto, Shinsuke, Shigeo Hara y Toshihiko Takenobu. "A Splint-to-CT Data Registration Strategy for Maxillary Navigation Surgery". Case Reports in Dentistry 2020 (4 de diciembre de 2020): 1–7. http://dx.doi.org/10.1155/2020/8871148.

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Computer-assisted navigation plays an important role in modern craniomaxillofacial surgery. Although headpins and skull posts are widely used for the fixation of the reference frame, they require the use of invasive procedures. Headbands are easily displaced intraoperatively, thus reducing the accuracy of the surgical outcome. This study reported the utility of a novel splint integrated with a reference frame and registration markers for maxillary navigation surgery. A maxillary splint with a 10 cm resin handle was fabricated before surgery, to fix the reference frame to the splint. The splint was set after the incorporation of fiducial gutta-percha markers into both the splint and resin handle for marker-based pair-point registration. A computed tomography (CT) scan was acquired for preoperative CT-based planning. A marker-based pair-point registration procedure can be completed easily and noninvasively using this custom-made integrated splint, and maxillary navigation surgery can be performed with high accuracy. This method also provides maximum convenience for the surgeon, as the splint does not require reregistration, and can be removed temporarily when required. The splint-to-CT data registration strategy has potential applicability not only for maxillary surgery but also for otolaryngologic surgery, neurosurgery, and surgical repair after craniofacial trauma.

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De Riek, J. "ARE MOLECULAR MARKERS STRENGTHENING PLANT VARIETY REGISTRATION AND PROTECTION?" Acta Horticulturae, n.º 552 (julio de 2001): 215–24. http://dx.doi.org/10.17660/actahortic.2001.552.24.

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Maurer, C. R., J. M. Fitzpatrick, M. Y. Wang, R. L. Galloway, R. J. Maciunas y G. S. Allen. "Registration of head volume images using implantable fiducial markers". IEEE Transactions on Medical Imaging 16, n.º 4 (1997): 447–62. http://dx.doi.org/10.1109/42.611354.

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Han, Yen-Ting, Wei-Chun Lin, Fang-Yu Fan, Chih-Long Chen, Chia-Cheng Lin y Hsin-Chung Cheng. "Comparison of Dental Surface Image Registration and Fiducial Marker Registration: An In Vivo Accuracy Study of Static Computer-Assisted Implant Surgery". Journal of Clinical Medicine 10, n.º 18 (16 de septiembre de 2021): 4183. http://dx.doi.org/10.3390/jcm10184183.

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This study compared the accuracy of static computer-assisted implant surgery (sCAIS) planned through dental surface image registration and fiducial marker registration. Stone models of 30 patients were converted into digital dental casts by using a desktop scanner. Cone-beam computed tomography (CBCT) was performed and superimposed to the digital dental casts with two methods: matching the dental surface images or matching the fiducial markers on a stereolithographic radiographic template. Following the implant planning, stereolithographic surgical guides were fabricated, and 56 fully guided implants were inserted by the same doctor. Deviations between planned and inserted implants were measured and compared using postoperative CBCT images. After adjustment for other potential influencing factors, compared with the fiducial marker registration group, significantly larger mean lateral deviations were noted in the dental surface registration group at both the implant platform and apex (p = 0.0188 and 0.0371, respectively). However, the mean lateral deviations for the dental surface registration (0.83 ± 0.51 mm at implant platform and 1.24 ± 0.68 mm at implant apex) were comparable to the literature. In conclusion, our findings indicate that although sCAIS planned using dental surface image registration was not statistically as accurate as that using fiducial marker registration, its accuracy was satisfactory for clinical use.

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Schicho, Kurt, Michael Figl, Rudolf Seemann, Markus Donat, Michael L. Pretterklieber, Wolfgang Birkfellner, Astrid Reichwein et al. "Comparison of laser surface scanning and fiducial marker–based registration in frameless stereotaxy". Journal of Neurosurgery 106, n.º 4 (abril de 2007): 704–9. http://dx.doi.org/10.3171/jns.2007.106.4.704.

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✓The authors compared the accuracy of laser surface scanning patient registration using the commercially available Fazer (Medtronic, Inc.) with the conventional registration procedure based on fiducial markers (FMs) in computer-assisted surgery. Four anatomical head specimens were prepared with 10 titanium microscrews placed at defined locations and scanned with a 16-slice spiral computed tomography unit. To compare the two registration methods, each method was applied five times for each cadaveric specimen; thus data were obtained from 40 registrations. Five microscrews (selected following a randomization protocol) were used for each FM-based registration; the other five FMs were selected for coordinate measurements by touching with a point measurement stylus. Coordinates of these points were also measured manually on the screen of the navigation computer. Coordinates were measured in the same manner after laser surface registration. The root mean square error as calculated by the navigation system ranged from 1.3 to 3.2 mm (mean 1.8 mm) with the Fazer and from 0.3 to 1.8 mm (mean 1.0 mm) with FM-based registration. The overall mean deviations (the arithmetic mean of the mean deviations of measurements on the four specimens) were 3.0 mm (standard deviation [SD] range 1.4–2.6 mm) with the Fazer and 1.4 mm (SD range 0.4–0.9 mm) with the FMs. The Fazer registration scans 300 surface points. Statistical tests showed the difference in the accuracy of these methods to be highly significant. In accordance with the findings of other groups, the authors concluded that the inclusion of a larger number of registration points might improve the accuracy of Fazer registration.

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Liu, Jia, Jingjing Zhang, Jianhui Mei y Xiaorui Zhang. "CH-Marker: A Color Marker Robust to Occlusion for Augmented Reality". International Journal of Pattern Recognition and Artificial Intelligence 32, n.º 02 (12 de noviembre de 2017): 1854004. http://dx.doi.org/10.1142/s0218001418540046.

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Fiducial marker systems are composed of a number of patterns that are mounted in the environment and automatically detected by computer vision algorithms using digital techniques. Thus, these systems are valuable in augmented reality (AR), robot navigation, and other applications. This paper proposes a new AR marker called CH-marker, which uses Hamming check codes to encode multiple kinds of colors and restore binary codes in the squares occluded in the markers. The marker solves the registration failure, which occurs when the markers are partially occluded in dynamic scenes. Experiments showed that the proposed marker is effective, reliable, and can meet the application demand of AR.

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Pfisterer, Wolfgang K., Stephen Papadopoulos, Denise A. Drumm, Kris Smith y Mark C. Preul. "Fiducial Versus Nonfiducial Neuronavigation Registration Assessment and Considerations of Accuracy". Operative Neurosurgery 62, suppl_1 (1 de marzo de 2008): ONS201—ONS208. http://dx.doi.org/10.1227/01.neu.0000317394.14303.99.

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Abstract Objective: For frameless stereotaxy, users can choose between anatomic landmarks (ALs) or surface fiducial markers (FMs) for their match points during registration to define an alignment of the head in the physical and radiographic image space. In this study, we sought to determine the concordance among a point-merged FM registration, a point-merged AL registration, and a combined point-merged anatomic/surface-merged (SM) registration, i.e., to determine the accuracy of registration techniques with and without FMs by examining the extent of agreement between the system-generated predicted value and physical measured values. Methods: We examined 30 volunteers treated with gamma knife surgery. The frameless stereotactic image-guidance system called the StealthStation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used. Nine FMs were placed on the patient's head and four were placed on a Leksell frame rod-box, which acted as a rigid set to determine the difference in error. For each registration form, we recorded the generated measurement (GM) and the physical measurement (PM) to each of the four checkpoint FMs. Bland and Altman plot difference analyses were used to compare measurement techniques. Correlations and descriptive analyses were completed. Results: The mean of values for GMs were 1.14 mm for FM, 2.3 mm for AL, and 0.96 mm for SM registrations. The mean errors of the checkpoints were 3.49 mm for FM, 3.96 mm for AL, and 3.33 mm for SM registrations. The correlation between GMs and PMs indicated a linear relationship for all three methods. AL registration demonstrated the greatest mean difference, followed by FM registration; SM registration had the smallest difference between GMs and PMs. Differences in the anatomic registration methods, including SM registration, compared with FM registration were within a mean ± 1.96 (standard deviation) according to the Bland and Altman analysis. Conclusion: For our sample of 30 patients, all three registration methods provided comparable distances to the target tissue for surgical procedures. Users may safely choose anatomic registration as a less costly and more time-efficient registration method for frameless stereotaxy.

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Krol, Andrezej, Mehmet Z. Unlu, Karl G. Baum, James A. Mandel, Wei Lee, Ioana L. Coman, Edward D. Lipson y David H. Feiglin. "MRI/PET nonrigid breast-image registration using skin fiducial markers". Physica Medica 21 (enero de 2006): 39–43. http://dx.doi.org/10.1016/s1120-1797(06)80022-0.

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Munck, Jan C. de, Frans C. Verster, Eric A. Dubois, Jan B. A. Habraken, Bert Boltjes, Jules J. Claus y Marcel van Herk. "Registration of MR and SPECT without using external fiducial markers". Physics in Medicine and Biology 43, n.º 5 (1 de mayo de 1998): 1255–69. http://dx.doi.org/10.1088/0031-9155/43/5/015.

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Asayama, Hirotaka, Daisuke Iwai y Kosuke Sato. "Fabricating Diminishable Visual Markers for Geometric Registration in Projection Mapping". IEEE Transactions on Visualization and Computer Graphics 24, n.º 2 (1 de febrero de 2018): 1091–102. http://dx.doi.org/10.1109/tvcg.2017.2657634.

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Cheng, Alexis, Jin U. Kang, Russell H. Taylor y Emad M. Boctor. "Direct three-dimensional ultrasound-to-video registration using photoacoustic markers". Journal of Biomedical Optics 18, n.º 6 (17 de junio de 2013): 066013. http://dx.doi.org/10.1117/1.jbo.18.6.066013.

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Salehi, Sean A. y Stephen L. Ondra. "Use of Internal Fiducial Markers in Frameless Stereotactic Navigational Systems during Spinal Surgery: Technical Note". Neurosurgery 47, n.º 6 (1 de diciembre de 2000): 1460–62. http://dx.doi.org/10.1097/00006123-200012000-00047.

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ABSTRACT OBJECTIVE The use of frameless stereotaxy has expanded the spine surgeon's ability to perform surgical procedures with instrumentation in areas of narrow anatomic tolerance. In many circumstances, however, it is difficult to register the frameless stereotactic probe using known anatomic landmarks. This occurs typically because landmarks are indistinct, and congenital or surgical defects limit the availability of anatomic fiducials. We propose an accurate and efficient method for registering the frameless stereotactic probe for spinal surgery when a staged procedure is planned. METHODS During the first stage of a planned two-stage procedure, a minimum of four cranial fiducial screws are implanted in the posterior element of each vertebra in which stereotactic registration is desired. Stage 1 is completed, and all suture closure is performed. A computed tomographic scan formatted for the frameless stereotactic unit is obtained postoperatively. In the second stage of surgery, registration is performed using cranial screws as internal fiducial markers. RESULTS Registration is performed easily and quickly using cranial screws as internal fiducial markers. No more than four registration points are necessary to calibrate the system to accuracy within 1.5 mm. CONCLUSION Implantation of fiducial markers during Stage 1 of a complex staged spinal surgery renders the frameless stereotactic navigational system registration extremely fast and accurate. We advocate the technique to enhance the use of frameless navigational systems for reliable and quick registration of the spine.

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Zhang, Yang y Lin Li. "AR Sand Table with VSTAR System". Key Engineering Materials 480-481 (junio de 2011): 650–55. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.650.

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We have proposed a three-dimensional sand table based on the video see-through tabletop augmented reality (VSTAR) system. The hybrid registration algorithm is used combining marker-based OI iterative computer vision method and photoelectric encoders mechanical tracking method instead of computer vision method only, which makes tracking does not dependent on markers, so that the tracking field of vision is not limited to the scope of markers. The system is of high precision and can be used for architecture design show, military topography simulation, museum exhibition and other virtual sand table applications.

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Metzger, Marc Christian, Amir Rafii, Bettina Holhweg-Majert, Annette M. Pham y Brad Strong. "Comparison of 4 Registration Strategies for Computer-Aided Maxillofacial Surgery". Otolaryngology–Head and Neck Surgery 137, n.º 1 (julio de 2007): 93–99. http://dx.doi.org/10.1016/j.otohns.2007.02.015.

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PURPOSE: Surgeons have recently started to use computer-aided surgery (CAS) to assist with maxillofacial reconstructive surgery. This study evaluates four different CAS registration strategies in the maxillofacial skeleton. MATERIALS AND METHODS: Fifteen fiducial markers were placed on each of four cadaveric heads. Four registration protocols were used: 1) group 1—invasive markers, 2) group 2—skin surface, 3) group 3—bony landmark, 4) group 4—intraoral splint. Two observers registered each head twice with each of the four protocols and measured the target registration error (TRE). The process was repeated on two different navigation systems for confirmation. RESULTS: The mean TRE values were: invasive, 1.13 ± 0.05 mm ( P < 0.05); skin, 2.03 ± 0.07 mm ( P < 0.05); bone, 3.17 ± 0.10 mm ( P < 0.05); and splint, 3.79 ± 0.13 mm ( P < 0.05). The TRE values were consistent across CAS systems. CONCLUSION: Of the techniques tested for CAS registration, invasive fiducial markers are the most accurate. Skin surface landmarks, bony landmarks, and an intraoral splint are incrementally less accurate.

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Zhang, Tie Feng, Bo Zhao, Guo Tao Lu, Jun Wang y Zhi Hui Sun. "A Miniature Handheld Automatic Detected Device for Register". Advanced Materials Research 174 (diciembre de 2010): 295–98. http://dx.doi.org/10.4028/www.scientific.net/amr.174.295.

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In present market, there is no automatic detected device for register in medium and small single-sheet offset, and the registration precision usually adjusted by handwork that is time-consuming and imprecision. To solve this problem, an automatic detected device for register of single-sheet offset based on image processing is proposed. The device takes photos of registration markers through high precision CMOS camera controlled by single chip computer, and then detects transversal deviation, longitudinal deviation, and diagonal deviation of registration markers through Hough transform. Experiments indicate that transversal deviation precision and longitudinal deviation precision of this device is 0.01 millimeter, when this automatic detected device is applied.

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Murphy, Michael Douglas, Diego Pinheiro, Rahul Iyengar, Gene Lim, Ronaldo Menezes y Martin Cadeiras. "A Data-Driven Social Network Intervention for Improving Organ Donation Awareness Among Minorities: Analysis and Optimization of a Cross-Sectional Study". Journal of Medical Internet Research 22, n.º 1 (14 de enero de 2020): e14605. http://dx.doi.org/10.2196/14605.

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Background Increasing the number of organ donors may enhance organ transplantation, and past health interventions have shown the potential to generate both large-scale and sustainable changes, particularly among minorities. Objective This study aimed to propose a conceptual data-driven framework that tracks digital markers of public organ donation awareness using Twitter and delivers an optimized social network intervention (SNI) to targeted audiences using Facebook. Methods We monitored digital markers of organ donation awareness across the United States over a 1-year period using Twitter and examined their association with organ donation registration. We delivered this SNI on Facebook with and without optimized awareness content (ie, educational content with a weblink to an online donor registration website) to low-income Hispanics in Los Angeles over a 1-month period and measured the daily number of impressions (ie, exposure to information) and clicks (ie, engagement) among the target audience. Results Digital markers of organ donation awareness on Twitter are associated with donation registration (beta=.0032; P<.001) such that 10 additional organ-related tweets are associated with a 3.20% (33,933/1,060,403) increase in the number of organ donor registrations at the city level. In addition, our SNI on Facebook effectively reached 1 million users, and the use of optimization significantly increased the rate of clicks per impression (beta=.0213; P<.004). Conclusions Our framework can provide a real-time characterization of organ donation awareness while effectively delivering tailored interventions to minority communities. It can complement past approaches to create large-scale, sustainable interventions that are capable of raising awareness and effectively mitigate disparities in organ donation.

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Hung, Min-Hsiung, en-Tzong Jeng, Chia-Lun Shu y Jia-Chiang Wang. "Optical Body-Surface Profiling with Coded Markers for Medical Image Registration". International Journal of Automation and Smart Technology 3, n.º 2 (1 de junio de 2013): 85–90. http://dx.doi.org/10.5875/ausmt.v3i2.193.

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Liu Xiaoli, 刘晓利, 彭翔 Peng Xiang, 殷永凯 Yin Yongkai, 李阿蒙 Li Ameng y 赵晓波 Zhao Xiaobo. "A Method for Global Registration of Range Data Combined with Markers". Acta Optica Sinica 29, n.º 4 (2009): 1010–14. http://dx.doi.org/10.3788/aos20092904.1010.

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Pohjonen, H., P. Nikkinen, O. Sipil�, J. Launes, E. Salli, O. Salonen, P. Karp, J. Yl�-J��ski, T. Katila y K. Liewendahl. "Registration and display of brain SPECT and MRI using external markers". Neuroradiology 38, n.º 2 (febrero de 1996): 108–14. http://dx.doi.org/10.1007/bf00604791.

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Pohjonen, H., P. Nikkinen, O. Sipil�, J. Launes, E. Salli, O. Salonen, P. Karp, J. Yl�-J��ski, T. Katila y K. Liewendahl. "Registration and display of brain SPECT and MRI using external markers". Neuroradiology 38, n.º 2 (1 de febrero de 1996): 108–14. http://dx.doi.org/10.1007/s002340050207.

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Sheriff, J., I. W. Fletcher y P. J. Cumpson. "Computer-readable Image Markers for Automated Registration in Correlative Microscopy – “autoCRIM”". Ultramicroscopy 228 (septiembre de 2021): 113322. http://dx.doi.org/10.1016/j.ultramic.2021.113322.

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Zhao, Chenchen, Xianbin Kong, Shuang Han, Xiaojiang Li, Tong Wu, Jie Zhou, Yuzhu Guo et al. "Analysis of differential metabolites in lung cancer patients based on metabolomics and bioinformatics". Future Oncology 16, n.º 18 (junio de 2020): 1269–87. http://dx.doi.org/10.2217/fon-2019-0818.

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Aim: Based on metabonomics, the metabolic markers of lung cancer patients were analyzed, combined with bioinformatics to explore the underlying disease mechanism. Materials & methods: Based on case–control design, using UPLC-Q-TOF/MS, urine metabolites were detected in discovery and validation set. Multivariate statistical analysis were performed to identify potential markers for lung cancer. A network analysis was constructed to integrate lung cancer disease targets with the above metabolic markers, and its possible mechanism and biological significance were explained. Results: A total of 35 potential markers were identified, 11 of which overlapped. Five key markers have a good linear correlation with serum biochemical indicators. Conclusion: The occurrence and development of lung cancer are closely related to disturbance of D-Glutamine and D-glutamate metabolism, amino acid imbalance. This test was registered on China clinical trial registration center ( www.chictr.org.cn/index.aspx ), registration number was ChiCTR1900025543.

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Marmulla, Rüdiger, Joachim Mühling y Georg Eggers. "Image-to-patient registration by natural anatomical surfaces of the head". Open Medicine 2, n.º 1 (1 de marzo de 2007): 89–102. http://dx.doi.org/10.2478/s11536-006-0042-7.

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AbstractThe use of registration markers in computer-assisted surgery is combined with high logistic costs and efforts.During the preparation of image guided surgery, automated markerless patient-to-image registration based on anatomical surfaces allows a significant reduction of preoperative effort and of the radiation dose the patient is exposed to. Placement and measurement of radio-opaque fiducial markers becomes unnecessary. The usability of face, auricle, maxilla and mandible for surface-based registration to CT image data was investigated. The present study was performed to evaluate the clinical accuracy in finding defined target points within the surgical site after markerless patient registration in image-guided oral and maxillofacial surgery.Preoperatively, the spatial position of 20 patients was registered to CT image data using a 3D laser surface scanner. Indications for surgery were tumours, foreign bodies and skeletal malformations. The accuracy of this surface-based registration was verified using additionally placed fiducial markers.The study showed, that markerless surface-based registration was sufficiently accurate for clinical use when the surface used for matching was the upper jaw, the face, or — with reservations — the auricle. Surface-based registration using the mandible did not yield satisfying results. To conclude, image-to-patient registration based on laser surface scanning is a valuable method for surgery of the head. Multiple sites of the head were identified as appropriate for the method. Hence, dependent on the individual case and the intended surgery, the registration area can be selected with the necessary flexibility.

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Cowan, Stephanie F., Emily R. Leeming, Andrew Sinclair, Aimee L. Dordevic, Helen Truby y Simone J. Gibson. "Effect of whole foods and dietary patterns on markers of subclinical inflammation in weight-stable overweight and obese adults: a systematic review". Nutrition Reviews 78, n.º 1 (20 de agosto de 2019): 19–38. http://dx.doi.org/10.1093/nutrit/nuz030.

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Abstract Context Reduction of subclinical inflammation is a potential target for chronic disease management. Adiposity is a known modifier of meta-inflammation; however, the influence of dietary factors is less clear. Objective This review examines evidence from human trials evaluating effects of whole foods or dietary patterns on circulating inflammatory markers in weight-stable overweight and obese adults. It is the first review to investigate effects of diet on inflammation, independent of changes in adiposity. Data Sources The Ovid MEDLINE, EMBASE, CINAHL, and Cochrane databases were searched. Data Extraction Data extraction was conducted using the Cochrane Collaboration Handbook for Systematic Reviews of Interventions. Data Analysis Study quality was evaluated using the Cochrane Collaboration Risk of Bias Assessment tool. Thirty-three studies were included assessing effects of 17 foods and dietary patterns on 39 inflammatory markers. Conclusions Overall, foods and dietary patterns were not found to have significant effects on inflammatory markers in weight-stable individuals. Inconsistencies among studies were largely due to methodological limitations. Future research should invest in longer intervention periods and standardization of inflammatory marker panels paired with novel technologies, while ensuring anthropometric measures are monitored and adequately controls are used. Systematic Review Registration Prospero registration number CRD42017067765.

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Cooke, Robert J. y James C. Reeves. "Plant genetic resources and molecular markers: variety registration in a new era". Plant Genetic Resources 1, n.º 2-3 (agosto de 2003): 81–87. http://dx.doi.org/10.1079/pgr200312.

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AbstractVariety registration is an important area of plant genetic resource characterization and utilization. Within the European Union, varieties must be included on a National List (NL) of a member state or on the Common Catalogue (a compilation of the NLs of the member states) before seed can be sold. This requires a series of tests and trials which assess if the variety is distinct, uniform and stable (DUS) and if it has sufficient value for cultivation and use (VCU). The same DUS criteria are also used world-wide for the granting of Plant Breeders' Rights (PBR), an intellectual property protection system. Both DUS and VCU are currently assessed primarily using field-based trials. However, the potential use of biochemical and molecular markers for DUS purposes is being actively investigated and such markers could have an important role to play in maintaining the quality and scope of PBR in an environment where the increasing number of countries involved in DUS testing and the number of variety comparisons to be made are causing logistical difficulties. More recently, given firstly the increase in the availability of markers from expressed regions of the genome, and secondly the possibilities raised by detailed DNA sequencing programmes and the association of markers (particularly single nucleotide polymorphisms, SNPs) with specific genes, the prospects for a more molecular approach to VCU are also being discussed. This paper reviews the current situation with regard to the use of molecular markers for DUS and VCU testing and considers future prospects for variety registration in the 21st century, ‘-omics’, era.

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Mela, Christopher, Francis Papay y Yang Liu. "Novel Multimodal, Multiscale Imaging System with Augmented Reality". Diagnostics 11, n.º 3 (4 de marzo de 2021): 441. http://dx.doi.org/10.3390/diagnostics11030441.

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A novel multimodal, multiscale imaging system with augmented reality capability were developed and characterized. The system offers 3D color reflectance imaging, 3D fluorescence imaging, and augmented reality in real time. Multiscale fluorescence imaging was enabled by developing and integrating an in vivo fiber-optic microscope. Real-time ultrasound-fluorescence multimodal imaging used optically tracked fiducial markers for registration. Tomographical data are also incorporated using optically tracked fiducial markers for registration. Furthermore, we characterized system performance and registration accuracy in a benchtop setting. The multiscale fluorescence imaging facilitated assessing the functional status of tissues, extending the minimal resolution of fluorescence imaging to ~17.5 µm. The system achieved a mean of Target Registration error of less than 2 mm for registering fluorescence images to ultrasound images and MRI-based 3D model, which is within clinically acceptable range. The low latency and high frame rate of the prototype system has shown the promise of applying the reported techniques in clinically relevant settings in the future.

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Zhu, Qingsong, Jia Gu y Yaoqin Xie. "Deformable Image Registration with Inclusion of Autodetected Homologous Tissue Features". Scientific World Journal 2012 (2012): 1–8. http://dx.doi.org/10.1100/2012/913693.

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A novel deformable registration algorithm is proposed in the application of radiation therapy. The algorithm starts with autodetection of a number of points with distinct tissue features. The feature points are then matched by using the scale invariance features transform (SIFT) method. The associated feature point pairs are served as landmarks for the subsequent thin plate spline (TPS) interpolation. Several registration experiments using both digital phantom and clinical data demonstrate the accuracy and efficiency of the method. For the 3D phantom case, markers with error less than 2 mm are over 85% of total test markers, and it takes only 2-3 minutes for 3D feature points association. The proposed method provides a clinically practical solution and should be valuable for various image-guided radiation therapy (IGRT) applications.

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Harasaki, Shunsuke y Hideo Saito. "Virtual Object Overlay onto Uncalibrated Camera Image Sequence Enabling Tracking of Natural Features". Journal of Robotics and Mechatronics 15, n.º 3 (20 de junio de 2003): 263–70. http://dx.doi.org/10.20965/jrm.2003.p0263.

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We discuss new geometric registration overlaying a virtual object onto an uncalibrated camera image sequence enabling extracting and tracking of natural features. To achieve correct registration, we apply a special space defined by two base images and trifocal tensors between base images and uncalibrated camera images. By extracting and tracking natural features, we construct augmented reality without markers whose 3D positions are known. Since we apply points and lines, fewer registration errors occur.

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Lin, Chia-Cheng, Ching-Zong Wu, Mao-Suan Huang, Chiung-Fang Huang, Hsin-Chung Cheng y Dayen Peter Wang. "Fully Digital Workflow for Planning Static Guided Implant Surgery: A Prospective Accuracy Study". Journal of Clinical Medicine 9, n.º 4 (1 de abril de 2020): 980. http://dx.doi.org/10.3390/jcm9040980.

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The accuracy of static guided implant surgery (sGIS) using conventional planning workflow has been extensively examined; however, more information is required to justify the application of fully digital planning protocol. The purpose of this study was to investigate the clinical accuracy of sGIS with a fully digital planning workflow. Twenty-one partially edentulous patients were enrolled in this prospective study. Cone-beam computed tomography (CBCT) and intraoral scans were taken and superimposed by matching the dental surface images directly (surface registration protocol) or by matching fiducial markers on a stereolithographic (SLA) radiographic template fabricated from the digital data of the intraoral scan (fiducial marker registration protocol). Virtual implant treatment plans were then determined, and tooth-supported SLA surgical guides were fabricated according to the plans. Twenty-six implant surgeries were performed via the surgical guide by one surgeon. Pre- and post-operative CBCT images were superimposed, and the positional and angular deviations between placed and planned implants were measured with metrology software. A total of 43 fully guided implants were placed, in which 25 implants were planned with the surface registration protocol. Implants planned based on the surface registration protocol had a larger mean angular deviation than the fiducial marker registration protocol. No significant differences were found for any deviations of the examined variables. Within the limits of this study, we concluded that the clinical accuracy of the sGIS planned with a fully digital workflow was consistent with the conventional workflow for partially edentulous patients.

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Pérez-Pachón, Laura, Parivrudh Sharma, Helena Brech, Jenny Gregory, Terry Lowe, Matthieu Poyade y Flora Gröning. "Effect of marker position and size on the registration accuracy of HoloLens in a non-clinical setting with implications for high-precision surgical tasks". International Journal of Computer Assisted Radiology and Surgery 16, n.º 6 (15 de abril de 2021): 955–66. http://dx.doi.org/10.1007/s11548-021-02354-9.

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Abstract Purpose Emerging holographic headsets can be used to register patient-specific virtual models obtained from medical scans with the patient’s body. Maximising accuracy of the virtual models’ inclination angle and position (ideally, ≤ 2° and ≤ 2 mm, respectively, as in currently approved navigation systems) is vital for this application to be useful. This study investigated the accuracy with which a holographic headset registers virtual models with real-world features based on the position and size of image markers. Methods HoloLens® and the image-pattern-recognition tool Vuforia Engine™ were used to overlay a 5-cm-radius virtual hexagon on a monitor’s surface in a predefined position. The headset’s camera detection of an image marker (displayed on the monitor) triggered the rendering of the virtual hexagon on the headset’s lenses. 4 × 4, 8 × 8 and 12 × 12 cm image markers displayed at nine different positions were used. In total, the position and dimensions of 114 virtual hexagons were measured on photographs captured by the headset’s camera. Results Some image marker positions and the smallest image marker (4 × 4 cm) led to larger errors in the perceived dimensions of the virtual models than other image marker positions and larger markers (8 × 8 and 12 × 12 cm). ≤ 2° and ≤ 2 mm errors were found in 70.7% and 76% of cases, respectively. Conclusion Errors obtained in a non-negligible percentage of cases are not acceptable for certain surgical tasks (e.g. the identification of correct trajectories of surgical instruments). Achieving sufficient accuracy with image marker sizes that meet surgical needs and regardless of image marker position remains a challenge.

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Zhu, Ning, Mohammad Najafi, Bin Han, Steven Hancock y Dimitre Hristov. "Feasibility of Image Registration for Ultrasound-Guided Prostate Radiotherapy Based on Similarity Measurement by a Convolutional Neural Network". Technology in Cancer Research & Treatment 18 (1 de enero de 2019): 153303381882196. http://dx.doi.org/10.1177/1533033818821964.

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Purpose: Registration of 3-dimensional ultrasound images poses a challenge for ultrasound-guided radiation therapy of the prostate since ultrasound image content changes significantly with anatomic motion and ultrasound probe position. The purpose of this work is to investigate the feasibility of using a pretrained deep convolutional neural network for similarity measurement in image registration of 3-dimensional transperineal ultrasound prostate images. Methods: We propose convolutional neural network-based registration that maximizes a similarity score between 2 identical in size 3-dimensional regions of interest: one encompassing the prostate within a simulation (reference) 3-dimensional ultrasound image and another that sweeps different spatial locations around the expected prostate position within a pretreatment 3-dimensional ultrasound image. The similarity score is calculated by (1) extracting pairs of corresponding 2-dimensional slices (patches) from the regions of interest, (2) providing these pairs as an input to a pretrained convolutional neural network which assigns a similarity score to each pair, and (3) calculating an overall similarity by summing all pairwise scores. The convolutional neural network method was evaluated against ground truth registrations determined by matching implanted fiducial markers visualized in a pretreatment orthogonal pair of x-ray images. The convolutional neural network method was further compared to manual registration and a standard commonly used intensity-based automatic registration approach based on advanced normalized correlation. Results: For 83 image pairs from 5 patients, convolutional neural network registration errors were smaller than 5 mm in 81% of the cases. In comparison, manual registration errors were smaller than 5 mm in 61% of the cases and advanced normalized correlation registration errors were smaller than 5 mm only in 25% of the cases. Conclusion: Convolutional neural network evaluation against manual registration and an advanced normalized correlation -based registration demonstrated better accuracy and reliability of the convolutional neural network. This suggests that with training on a large data set of transperineal ultrasound prostate images, the convolutional neural network method has potential for robust ultrasound-to-ultrasound registration.

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Lee, Chia-Yen, Chung-Ming Chen, Hao-Jen Wang, Jhih-Hao Lai, Chi-En Lee, Fan-Ya Lin, Ming-Jui Chung, Yeun-Chung Chang y Chiun-Sheng Huang. "Longitudinal Infrared Image Registration Without Adhesive Markers for Breast Cancer Chemotherapy Patients". Journal of Medical Imaging and Health Informatics 8, n.º 3 (1 de marzo de 2018): 516–25. http://dx.doi.org/10.1166/jmihi.2018.2314.

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Kozhukhova, N. E. y Yu M. Sivolap. "Identification and Registration of Maize Genotypes with the Use of Molecular Markers". Russian Journal of Genetics 40, n.º 1 (enero de 2004): 49–55. http://dx.doi.org/10.1023/b:ruge.0000013448.70285.83.

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Jamali, Seyed Hossein, James Cockram y Lee T. Hickey. "Insights into deployment of DNA markers in plant variety protection and registration". Theoretical and Applied Genetics 132, n.º 7 (2 de mayo de 2019): 1911–29. http://dx.doi.org/10.1007/s00122-019-03348-7.

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Zanetti, T. C., S. Q. Brunetto, E. M. Souza, L. D. S. Sachinelli, C. D. Ramos y D. E. Zantut-Wittmann. "Comparison of different fiducial markers to guide SPECT and CT image registration". Journal of Instrumentation 16, n.º 05 (1 de mayo de 2021): T05003. http://dx.doi.org/10.1088/1748-0221/16/05/t05003.

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Więcławska, Edyta. "Discrete units as markers of English/Polish contrasts in company registration discourse". Linguodidactica 24 (2020): 309–27. http://dx.doi.org/10.15290/lingdid.2020.24.22.

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The paper addresses the issue of the complexity of legal communication in an interlingual perspective. The analysis fits in the paradigmatic approach to contrastive studies, where the distribution of discrete units is presented in quantitative terms. The cross-linguistic, computational account of the distribution of selected discrete units across company registration documentation shows systemic distinctions. It discloses recurrent, symmetrical and asymmetrical patterns which result from language system-inherent distinctions and/or the operation of translation universals. The strong point of the research lies in addressing legal communication within the realm of secondary genres, which – for practical reasons – are underrepresented in jurilinguistic studies. The study is based on a custom -designed, parallel corpus comprised of authentic materials.

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Wan, Shu-Yen, Lun-Jou Lo y Che-Yao Chang. "Disturbance-Region Removal on Landmark-less Registration of Craniofacial Images Acquired by CBCT and 3D Photography". International Journal of Emerging Technology and Advanced Engineering 11, n.º 3 (25 de marzo de 2021): 1–7. http://dx.doi.org/10.46338/ijetae0321_01.

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Superimposition of cranio-maxillofacial images acquired from cone-beam computed tomography (CBCT) and facial images acquired from three-dimensional photography (3D photography) can assist in diagnosis and surgical planning. Conventional approaches individually identified prominent facial landmarks on both modalities, respectively and assessed their correspondence. Considering, however, variation of facial expressions or drastic feature distortion when the face or head was imaged at different timing, landmark registration can become challenging. This paper proposes a disturbance-region removal (DRR) procedure to improve the efficacy of registration. The disturbance regions (DRs) are defined as those exhibiting strong responses in the concavity intensity maps that are computed from the facial surface mesh. Following this identification process for the DRs, an adapted symmetric region growing algorithm is used to form the connected DRs that are to be removed prior to superimposition of both modalities. The results show a twenty-eight percent better match of overall correspondence of the facial fiducial markers. Instead of being the registration guides in conventional approaches, in this study the fiducial markers are employed as only a means to assess the performance of registration

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Nagaraj, Yeshaswini, Bjoern Menze y Michael Friebe. "US/MRI fusion with new optical tracking and marker approach for interventional procedures inside the MRI suite". Current Directions in Biomedical Engineering 2, n.º 1 (1 de septiembre de 2016): 459–62. http://dx.doi.org/10.1515/cdbme-2016-0101.

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AbstractInterventional MRI in closed bore high-field systems is a challenge due to limited space and the need of dedicated MRI compatible equipment and tools. A possible solution could be to perform an ultrasound procedure for guidance of the therapy tools outside the bore, but still on the MRI patient bed. That could track and subsequently combine the superior images of MRI with the real-time features of ultrasound. Conventional optical tracking systems suffer from line of sight issues and electromagnetic tracking does not perform well in the presence of magnetic fields. Hence, to overcome these issues a new optical tracking system called inside-out tracking is used. In this approach, the camera is directly attached to the US probe and the markers are placed onto the patient to achieve the location information of the US slice. The evaluation of our novel system of framed fusion markers can easily be adapted to various imaging modalities without losing image registration. To confirm this evaluation, phantom studies with MRI and US imaging were carried out using a point-registration algorithm along with a similarity measure for fusion. In the inside-out system approach, image registration was found to yield an accuracy of upto 4 mm, depending on the imaging modality and the employed marker arrangement and with that provides an accuracy that cannot be easily achieved by combining pre-operative MRI with live ultrasound.

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Thompson, Eric M., Gregory J. Anderson, Colin M. Roberts, Matthew A. Hunt y Nathan R. Selden. "Skull-fixated fiducial markers improve accuracy in staged frameless stereotactic epilepsy surgery in children". Journal of Neurosurgery: Pediatrics 7, n.º 1 (enero de 2011): 116–19. http://dx.doi.org/10.3171/2010.10.peds10352.

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Object Surgery to monitor and resect epileptogenic foci may be undertaken in 2 stages, providing an opportunity to use skull-fixated fiducials implanted during the first stage to improve the accuracy of cortical resection during the second stage. This study compared the intrinsic accuracy of skin-based and skull-fixated fiducial markers in registering frameless stereotaxy during pediatric epilepsy surgery. To the authors' knowledge, these modalities of registration have not previously been directly compared in this population. Methods The authors undertook a retrospective review of pediatric patients who underwent resection of epileptogenic foci in 2 stages with frameless stereotactic assistance, performed by a single surgeon at Oregon Health & Science University. For the first stage (subdural grid implantation), 9 skin fiducial markers were used to register anatomical data in a frameless stereotactic station. Intraoperatively, four 3-mm screws were placed circumferentially around the craniotomy. Postoperatively, thin-slice brain MR and CT images were obtained and fused. For the second stage, the 4 screws were used as fiducial markers to register the stereotactic anatomical data. For both stages, accuracy (difference in millimeters from zero of the manual fiducial registration compared with the computer model) was determined using navigation software. The intrinsic accuracy of these 2 methods of fiducial registration was compared using a paired Student t-test. Results Between 2004 and 2009, 40 pediatric patients with epilepsy underwent frameless stereotactic surgical procedures. Fourteen patients who had 2-stage procedures using skin-based and skull-fixated registration with complete accuracy data were included in this retrospective review. Mean registration error was significantly lower using skull-fixated fiducials (1.35 mm, 95% CI 1.09–1.60 mm) than using skin-based fiducials (1.85 mm, 95% CI 1.56–2.13 mm; p = 0.0016). Conclusions A significantly higher degree of accuracy was achieved using 4 skull-fixated fiducials compared with using 9 skin-based fiducials. This simple and accurate method for registering frameless stereotactic anatomical data does not involve the potential time, expense, discomfort, and morbidity of extraoperative skull-fixated fiducial placement. The method described in this paper could also be extrapolated to other planned 2-stage cranial surgical procedures such as combined skull base approaches.

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Ruņgis, Dainis, Ilze Gaile, Ilze Veinberga, Sanita Zute, Vija Strazdiņa, Māra Bleidere y Arta Kronberga. "Use of DNA markers for cereal line uniformity assessment". Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences. 66, n.º 1-2 (1 de enero de 2012): 21–25. http://dx.doi.org/10.2478/v10046-011-0041-1.

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Use of DNA markers for cereal line uniformity assessment Prior to the registration of a new variety, it is required to undergo Distinctness, Uniformity and Stability (DUS) testing. Preparing a newly developed variety to meet the requirements of DUS testing is a lengthy process, particularly regarding aspects of uniformity and stability. Field testing of a large number of lines is time and resource intensive. In addition, the expression of certain traits may be influenced by environmental conditions. The use of DNA markers may allow rapid assessment of the level of genetic diversity within a particular line or variety, and to remove individuals that are genetically differentiated, thus accelerating the homogenisation of a newly developed variety. In this study, we utilised AFLP and the iPBS marker techniques to assess genetic variation within advanced breeding lines of several cereal species (triticale, wheat, barley). The combined use of molecular and morphological selection over three years of analysis and selection resulted in the reduction of genetic diversity within breeding lines.

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Corrado, Giandomenico, Maurizio La Mura, Orsola Ambrosino, Giuseppe Pugliano, Paola Varricchio y Rosa Rao. "Relationships of Campanian olive cultivars: comparative analysis of molecular and phenotypic data". Genome 52, n.º 8 (agosto de 2009): 692–700. http://dx.doi.org/10.1139/g09-044.

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Estimation of the genetic relatedness of traditional olive cultivars with genetic markers and phenotypic data enables progress in plant breeding, management of genetic resources, and protection of both breeders’ rights and certified premium products. We used amplified fragment length polymorphisms (AFLPs), simple sequence repeats (SSRs), and quantitative and qualitative morphological traits, including characteristics recommended for variety registration, to study genetic diversity and relationships in the olive at different levels. The 14 varieties analyzed, which are used for the production of Protected Denomination of Origin extra-virgin olive oil, represent the most important cultivars in the Campania region of Italy and typify a regional diversity characteristic of traditional olive cultivation. The genetic distances obtained with the two DNA marker systems were significantly correlated, as were those obtained by quantitative and qualitative traits. A lower but significant correlation was also observed between distances based on molecular markers and quantitative traits, but qualitative traits, even if sampled in high numbers, failed to describe the pattern of molecular similarity. Our data imply that the type and the number of phenotypic traits scored can greatly influence the outcome of the analysis, and care should be taken when qualitative and quantitative data are combined. Furthermore, the data indicate that the two molecular marker systems are useful for investigating genetic relationships, but they may also be used to complement and assist the traditional registration of varieties. We propose that since the information provided by molecular and morphological marker systems in olive is different, they should serve different purposes.

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