Dissertations / Theses on the topic 'Tissue volumetry'

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, June 2006.
Includes bibliographical references (leaf 41).
Cell morphology of tissue is naturally three-dimensional. Most current methods for tissue analysis use two dimensional histological images of the tissue samples, restricting the analysis to 2D. Existing approaches do not provide essential three-dimensional information such as cell volume, shape and structural orientation of cells within the tissue. This thesis investigates a method to extract three dimensional data using two-dimensional microscopy. We demonstrate that three dimensional cell structure can be acquired using two dimensional fluorescence microscopy and two-photon microscopy and explore the application of the analysis to studies of cardiac tissue.
by Francisco Cruz.
M.Eng.

Three-dimensional (3D) bioprinting has become a fast-developing research field in the last few years. Many different technical solutions are available, with extrusion-based printing being the most promising and versatile method. In addition, a variety of biomaterials are already available for 3D printing of live cells. The real challenge, however, remains bioprinting of macroscopic, volumetric constructs of well-defined structures since hydrogels used for cell-embedding must consist of rather soft materials. This article describes recent developments to overcome these limitations that prevent clinical applications of bioprinted human tissues. New approaches include technical solutions such as in situ cross-linking or gelation processes that now can be performed during the bioprinting process, modified bioinks that combine suitable viscosity and cytocompatible gelation mechanisms, and utilization of additional materials to provide mechanical strength to the cell-laden constructs.

Automatic segmentation of human organs allows more accurate calculation of organ doses in radiationtreatment planning, as it adds prior information about the material composition of imaged tissues. For instance, the separation of tissues into bone, adipose tissue and remaining soft tissues allows to use tabulated material compositions of those tissues. This approximation is not perfect because of variability of tissue composition among patients, but is still better than no approximation at all. Another use for automated tissue segmentationis in model based iterative reconstruction algorithms. An example of such an algorithm is DIRA, which is developed at the Medical Radiation Physics and the Center for Medical Imaging Science and Visualization(CMIV) at Linköpings University. DIRA uses dual-energy computed tomography (DECT) data to decompose patient tissues into two or three base components. So far DIRA has used the MK2014 algorithm which segments human pelvis into bones, adipose tissue, gluteus maximus muscles and the prostate. One problem was that MK2014 was limited to 2D and it was not very robust. Aim: The aim of this thesis work was to extend the MK2014 to 3D as well as to improve it. The task was structured to the following activities: selection of suitable segmentation algorithms, evaluation of their results and combining of those to an automated segmentation algorithm. Of special interest was image registration usingthe Morphon. Methods: Several different algorithms were tested.  For instance: Otsu's method followed by threshold segmentation; histogram matching followed by threshold segmentation, region growing and hole-filling; affine phase-based registration and the Morphon. The best-performing algorithms were combined into the newly developed JJ2016. Results: For the segmentation of adipose tissue and the bones in the eight investigated data sets, the JJ2016 algorithm gave better results than the MK2014. The better results of the JJ2016 were achieved by: (i) a new segmentation algorithm for adipose tissue which was not affected by the amount of air surrounding the patient and segmented smaller regions of adipose tissue and (ii) a new filling algorithm for connecting segments of compact bone. The JJ2016 algorithm also estimates a likely position for the prostate and the rectum by combining linear and non-linear phase-based registration for atlas based segmentation. The estimated position (center point) was in most cases close to the true position of the organs. Several deficiencies of the MK2014 algorithm were removed but the improved version (MK2014v2) did not perform as well as the JJ2016. Conclusions: JJ2016 performed well for all data sets. The JJ2016 algorithm is usable for the intended application, but is (without further improvements) too slow for interactive usage. Additionally, a validation of the algorithm for clinical use should be performed on a larger number of data sets, covering the variability of patients in shape and size.

Magnetic resonance imaging (MRI) offers the unique ability to examine the heart in three dimensions and to provide tissue characterisation. This thesis aims to investigate two areas of particular interest, namely the quantification of cor pulmonale and acute myocardial infarction. The methods currently available for assessing right ventricular hypertrophy and dilatation are discussed, with particular reference to patients with chronic obstructive pulmonary disease. The results of pulmonary haemodynamic and blood gas data are compared with the results from cardiac gated MRI. A good correlation is obtained between the mean and systolic pulmonary artery pressures, the pulmonary vascular resistance and the right ventricular wall volume measured by MRI. This technique is subsequently used in a small group of patients, to determine the response to long term oxygen therapy. The various techniques employed to assess the size of myocardial infarcts are discussed, and the previous literature on the ability of MRI to detect infarction is reviewed. A new technique, which is supported by phantom experiments, is described to measure the volume of infarcted myocardium using saturation recovery - inversion recovery and spin-echo images. The T1 images are compared with radionuclide pyrophosphate scanning and serum creatine kinase-MB release and a satisfactory agreement obtained. Myocardial infarct size measured by both pulse sequences is compared directly. The spin-echo technique is used to assess alterations in myocardial infarct size with time and the response to various therapeutic options is compared. In conclusion the limitations of both techniques are discussed and future developments proposed.

Metal implants are a type of hard tissue replacement currently used. Metals used for implants include: stainless steel, titanium, chrome, and cobalt alloys. Such implants often fail at the interface with bone. Metal implants fail when the surface of the implant is coated with an osteoconductive material. An osteoconductive material provides scaffolding for cellular migration, cellular attachment, and cellular distribution. A reason for metal implant failure could be the vastly different material properties than bone. Motivation for the research was to find a suitable bone substitute other than metal. Materials considered were: zirconia toughened alumina, carbon fiber reinforced epoxy, and glass fiber reinforced epoxy. Those materials have been used in previous biological applications and can be cast into complex configurations. Objectives of the study were to compare material properties of the composites to bone. A method to create porosity was then tested in the material that was similar to bone in critical material property. Some of the materials were statistically similar to bone in yield strength. Method to create interconnected porosity in those materials resulted in 49% void space.

The purpose of this manuscript is to establish a unified theory of porohyperelasticity with transport and growth and to demonstrate the capability of this theory using a finite element model developed in MATLAB. We combine the theories of volumetric growth and mixed porohyperelasticity with transport and swelling (MPHETS) to derive a new method that models growth of biological soft tissues. The conservation equations and constitutive equations are developed for both solid-only growth and solid/fluid growth. An axisymmetric finite element framework is introduced for the new theory of growing MPHETS (GMPHETS). To illustrate the capabilities of this model, several example finite element test problems are considered using model geometry and material parameters based on experimental data from a porcine coronary artery. Multiple growth laws are considered, including time-driven, concentrationdriven, and stress-driven growth. Time-driven growth is compared against an exact analytical solution to validate the model. For concentration-dependent growth, changing the diffusivity (representing a change in drug) fundamentally changes growth behavior. We further demonstrate that for stress-dependent, solid-only growth of an artery, growth of an MPHETS model results in a more uniform hoop stress than growth in a hyperelastic model for the same amount of growth time using the same growth law. This may have implications in the context of developing residual stresses in soft tissues under intraluminal pressure. To our knowledge, this manuscript provides the first full description of an MPHETS model with growth. The developed computational framework can be used in concert with novel in-vitro and in-vivo experimental approaches to identify the governing growth laws for various soft tissues.

Many medical therapies, such as thermal tumor detection and hypothermia cancer treatments, utilize heat transfer mechanisms of the body. The focus of this work is the development and experimental validation of a method to simultaneously estimate thermal conductivity, volumetric specific heat, and perfusion of in-vivo tissue. The heat transfer through the tissue was modeled using a modified Pennes' equation. Using a least-squares parameter estimation method with regularization, the thermal properties could be estimated from the temperature response to the known applied heat flux. The method was tested experimentally using a new agar-water tissue phantom designed for this purpose. A total of 40 tests were performed. The results of the experiments show that conductivity can be successfully estimated for perfused tissue phantoms. The values returned for volumetric specific heat are lower than expected, while the estimated values of perfusion are far greater than expected. It is believed that the mathematical model is incorrectly accounting between these two terms. Both terms were treated as heat sinks, so it is conceivable that it is not discriminating between them correctly. Although the method can estimate all three parameters simultaneously, but it seems that the mathematical model is not accurately describing the system. In the future, improvements to the model could be made to allow the method to function accurately.
Master of Science

Segmentation of scanned tissue volumes of three-dimensional (3D) computed tomography (CT) images often involves—at least partially—some manual process, as there is no standardized automatic method. There is a need to develop fully automatic approaches, not only to improve the objectivity of the task, but also to increase the overall speed of the segmentation process. Here we extend a 3D local binary patterns (LBP) based trabecular bone segmentation method with adaptive local thresholding and additional segmentation parameters to make it more robust yet still perform adequately when compared to traditional user-assisted segmentation. We estimate parameters for the new automated adaptive multiscale LBP-based 3D segmentation method (AMLM) in our experimental setting, and have two micro-CT (μCT) scanned bovine trabecular bone tissue volumes segmented by both the AMLM and two experienced users. Comparison of the results shows superior performance of the AMLM suggesting the strong potential for this solution to perform automatic bone segmentation
Skannattujen kudosrakenteiden segmentointi kolmiulotteisista (3D) tomografiakuvista tehdään usein ainakin osittain manuaalisesti, sillä standardoitua automaattista menetelmää ei ole. Täysin automatisoitujen lähestymistapojen kehitys on tarpeen, sillä se parantaisi sekä segmentoinnin objektiivisuutta että sen kokonaisnopeutta. Tässä työssä laajennamme automatisoitua local binary patterns (LBP) -perustaista trabekulaarisen luun 3D-segmentointimenetelmää adaptiivisella paikallisella kynnystyksellä ja segmentoinnin lisäparametreilla tavoitteenamme vahvistaa menetelmää mutta säilyttää silti riittävä suorituskyky verrattuna perinteiseen käyttäjäavusteiseen segmentointiin. Arvioimme koejärjestelyssämme parametrit uudelle automatisoidulle adaptiiviselle moniasteikkoiselle LBP-pohjaiselle 3Dsegmentointimenetelmälle (AMLM), ja teetämme sekä AMLM:n avulla että kahden kokeneen käyttäjän toimesta binäärisegmentoinnit kahdelle mikrotietokonetomografialla (μTT) tuotetulle kuvalle naudan trabekulaarisesta luukudoksesta. Tulosten vertailu osoittaa AMLM:n suorituskyvyltään selkeästi paremmaksi, mikä antaa vahvan viitteen tämän menetelmän soveltuvuudesta automatisoituun luusegmentointiin

Objectives: Extraction of a tooth leads to a series of healing events that are intimately associated with dimensional changes in the alveolar ridge that typically result in a net volume loss. Previous studies have evaluated the extent and pattern of those resorptive changes, however it remains challenging to predict the degree of change that will occur, as numerous local and systemic factors may play a role in the biologic events that follow tooth extraction. The purpose of this study was to assess the role that phenotypic characteristics of the periodontium play in the alveolar ridge remodeling processes that take place following single tooth extraction. Methods: Healthy patients in need of a single tooth extraction in the maxillary arch from second premolar to second premolar (inclusive) and who met a predefined eligibility criteria were enrolled in this study. An impression of the maxillary arch was made and a cone beam computed tomography (CBCT) scan of the maxilla was obtained immediately prior to tooth extraction at the baseline visit. At the time of the extraction, clinical measurements were made including probing depth, bone sounding, buccal keratinized mucosa width, buccal and palatal alveolar bone thickness, and buccal and palatal soft tissue thickness. Fourteen weeks following the baseline intervention, patients returned to the clinic for a second impression of the maxillary arch and a second CBCT of the maxilla. Linear and volumetric bone measurements were made using the data obtained from the CBCT scans. The casts obtained from the impressions were digitally scanned and volumetric measurements were made from the digitized data to assess volume changes of the residual ridge. The primary outcome of interest was the volumetric percent reduction of the alveolar ridge following single tooth extraction. Spearman correlations were utilized to evaluate relationships between variables and modeling was completed to predict the percentage of volumetric change in the hard and soft tissues using the clinical variables. Results: A total of 21 patients participated in the study, 19 patients are included in this analysis (one patient has yet to complete the study, one patient was later excluded due to lack of compliance). Of the 19 extraction sites included, 17 were maxillary premolar teeth. At baseline, the average buccal plate thickness was 1.09 mm. After 14 weeks, the average loss of alveolar bone width was 1.66 mm. The average loss of buccal bone height was 1.10 mm and mean loss of palatal bone height was 1.36 mm. The average percentage volumetric reduction of the bone as measured from a CBCT scan was 26.42% after 14 weeks of healing. Mean percentage volumetric reduction of the ridge, as measured from a digitized cast, was 18.89%. There was no statistically significant correlation noted between the bone and ridge volumetric measurements. While there were no statistically significant correlations noted between the thickness of the buccal bone and the amount of volumetric remodeling, statistically significant negative correlations were found between the buccal bone thickness and the loss of alveolar bone width (rs = -0.66418, p-value = 0.0019). In addition, a statistically significant correlation was noted between the reduction in alveolar bone width and the loss of buccal ridge height (rs = 0.55707, p-value = 0.0132). Modeling methods found that increased thickness of the buccal soft tissue was predictive of increased percentage volumetric reduction of hard tissues (coeff = 37.24, p-value = 0.0301). Conclusions: Increased buccal soft tissue thickness was found to be predictive of increased percent volumetric reduction of alveolar bone. Thinner buccal bone was correlated with increased loss of alveolar bone width. While statistically significant correlations were identified, further studies with larger sample size are needed to better understand these relationships.

Fractures are a major public health concern and there is an urgent need to identify high-risk individuals. This study used novel approaches in bone imaging to characterize optimal skeletal development in girls and enhance our understanding of the structural and functional deficits that contribute to skeletal fragility and fracture risk during growth. The findings indicate that fracture in girls is associated with lower trabecular bone density, but not bone macro-architecture at metaphyseal regions of weight-bearing bones, which is consistent with findings reported in children at the distal radius. These findings suggest that lower trabecular density at metaphyseal regions of long bones track throughout the appendicular skeleton and may be an early marker of skeletal fragility.Obese children are overrepresented in childhood fracture cases. Nevertheless, the effects of fat on bone during growth remain unclear. This study showed that skeletal muscle was a stronger determinant of bone parameters in girls than total body adiposity, although fat mass had a persistent, albeit weak association with bone parameters. Furthermore, fatty infiltration of skeletal muscle, which is associated with type 2 diabetes mellitus, was inversely associated with bone strength in girls. These findings are consistent with the proposed functional model of bone development which posits that forces from muscle contractions are the main mechanical challenges to which bones adapt.Physical activity during growth is critical for optimal bone development. The findings from this study support this premise and suggest that regular physical activity enhances bone strength in girls. Nevertheless, for exercise to be accepted as an important public health osteoporosis prevention strategy, lasting adaptations must be shown. Plausible biological explanations have been offered in support of the peri-pubertal years as a "window of opportunity" for maximizing the response to exercise. Findings from this study suggest that a two year school-based high-impact jumping intervention was not an effective means to enhance bone parameters in girls. Controlled dose-response trials will be necessary to test questions regarding the types, bouts, and durations of exercise required to define the "dose" of exercise needed to elicit meaningful skeletal adaptations during growth.

This study compared a manual program for liver volumetry with a semiautomated software. The hypothesis was that the software would be faster, more accurate and less dependent on the evaluator’s experience. Materials and Methods: Ten patients undergoing hemihepatectomy were included into this IRB approved study after written informed consent. All patients underwent a preoperative abdominal CTScan, which was used for whole liver volumetry and volume prediction for the liver part to be resected. Two different softwares were used: 1) manual method: borders of the liver had to be defined per slice by the user; 2) semiautomated software: automatic identification of liver volume with manual assistance for definition of Couinaud-segments. Measurements were done by six observers with different experience levels. Water displacement volumetry immediately after partial liver resection served as gold standard. The resected part was examined with a CT-scan after displacement volumetry. Results: Volumetry of the resected liver scan showed excellent correlations to water displacement volumetry (manual: ρ=0.997; semiautomated software: ρ=0.995). Difference between the predicted volume and the real volume was significantly smaller with the semiautomated software than with the manual method (33 % vs. 57 %, p=0.002). The semiautomated software was almost four times faster for volumetry of the whole liver. Conclusion: Both methods for liver volumetry give an estimated liver volume close to the real one. The tested semiautomated software is faster, more accurate in predicting the volume of the resected liver part, gives more reproducible results and is less dependent on the user’s experience
Ziel dieser Studie war es, eine manuelle Methode zur Lebervolumetrie mit einer halbautomatischen Software zu vergleichen. Die zu prüfende Hypothese war eine Überlegenheit der halbautomatischen Software hinsichtlich Schnelligkeit, Genauigkeit und Unabhängigkeit von der Erfahrung des Auswerters. Material und Methoden: Die Studie wurde von der Ethikkommission geprüft und es lagen Einverständniserklärungen aller Patienten vor. In die Studie wurden zehn Patienten eingeschlossen, die eine Hemihepatektomie erhielten. Es wurde präoperativ ein CT-Scan angefertigt, der sowohl für die Volumetrie der gesamten Leber als auch zur Bestimmung des Resektatvolumens verwendet wurde. Für die Volumetrie wurden zwei verschiedene Programme genutzt: 1) eine manuelle Methode, wobei die Lebergrenzen in jeder Schicht vom Auswerter definiert werden mussten 2) eine halbautomatische Software mit automatischer Erkennung des Lebervolumens und manueller Definition der Lebersegmente nach Coinaud. Die Messungen wurden von sechs Auswertern mit unterschiedlicher Erfahrung vorgenommen. Als Goldstandard diente eine Verdrängungsvolumetrie des Leberresektats, die direkt nach der Resektion im Operationssaal durchgeführt wurde. Anschließend wurde zusätzlich ein CT-Scan des Resektats angefertigt. Ergebnisse: Die Ergebnisse des postoperativen CT-Scans korrelierten hochgradig mit den Ergebnissen der Verdrängungsvolumetrie (manuell: ρ=0.997; halbautomatische Software: ρ=0.995). Mit der halbautomatischen Software fielen die Unterschiede zwischen dem vorhergesagten und dem tatsächlichen Volumen signifikant kleiner aus (33 % vs. 57 %, p=0.002). Zudem lieferte die halbautomatische Software die Volumina der Gesamtleber 3.9mal schneller. Schlussfolgerung: Beide Methoden erlauben eine sehr gute Abschätzung des Lebervolumens. Die getestete halbautomatische Software kann das Lebervolumen jedoch schneller und das Resektatvolumen genauer vorhersagen und ist zusätzlich unabhängiger von der Erfahrung des Auswerters

The development of small diameter tissue engineered blood vessels (TEBVs) with low thrombogenicity, low immunogenicity, suitable mechanical properties, and a capacity to remodel to their environment could significantly advance the treatment of coronary and peripheral artery disease. Despite significant advances in the field of tissue engineering, autologous vessels are still primarily utilized as grafts during bypass surgeries. However, undamaged autologous tissue may not always be available due to disease or prior surgery. TEBVs lack long-term efficacy due to a variety of types of failures including aneurysmal dilations, thrombosis, and rupture; the mechanisms of these failures are not well understood. In vitro mechanical testing may help the understanding of these failure mechanisms. The typical mechanical tests lack standardized methodologies; thus, results vary widely. The overall goal of this study is to develop novel experimental and mathematical models to study the mechanical properties and failure mechanisms of TEBVs. Our results suggest that burst pressure tests, the current standard, are not sufficient to assess a TEBVs’ suitability as a coronary substitute; creep and/or cyclic loading tests are also required. Results from this model can help identify the most insightful experiments and quantities to be measured – ultimately reducing the overall number of experimental iterations. Improving the testing and characterization of TEBVs is critically important in decreasing the time necessary to validate the mechanical and functional responses of TEBVs over time, thus quickly moving TEBVs from the benchtop to the patient.

Includes bibliographical references.
Whilst the benefit of adjuvant radiotherapy in gastric cancer is known, the optimal means of delivery, including two dimensional conventional, three dimensional conformal radiotherapy, intensity modulated radiotherapy and volumetric modulated arc therapy is less certain. The purpose of this study is to assess and compare volumetric modulated arc therapy (VMAT) and three dimensional conformal radiotherapy (3DCRT) plans in adjuvant radiation of gastric cancer.

Volumetric muscle loss (VML) typically results from traumatic incidents; such as those presented from combat missions, where soft-tissue extremity injuries account for approximately 63% of diagnoses. These injuries lead to a devastating loss of function due to the complete destruction of large amounts of tissue and its native basement membrane, removing important biochemical cues such as hepatocyte growth factor (HGF), which initiates endogenous muscle regeneration by recruiting progenitor cells. Clinical strategies to treat these injuries consist of autologous tissue transfer techniques, requiring large amounts of healthy donor tissue and extensive surgical procedures that can result in donor site morbidity and limited functional recovery. As such, there is a clinical need for an off-the-shelf, bioactive scaffold that directs patient’s cells to align and differentiate into muscle tissue in situ. In this thesis, we developed fibrin microthreads, scaffolds composed of aligned fibrin material that direct cell alignment along the longitudinal axis of the microthread structure, with specific structural and biochemical properties to recreate structural cues lost in VML injuries. We hypothesized that fibrin microthreads with an increased resistance to proteolytic degradation and loaded with HGF would enhance the functional, mechanical regeneration of skeletal muscle tissue in a VML injury. We developed a crosslinking strategy to increase fibrin microthread resistance to enzymatic degradation, and increased their tensile strength and stiffness two- to three-fold. This crosslinking strategy enhanced the adsorption of HGF, facilitated its rapid release from microthreads for 2 to 3 days, and increased the chemotactic response of myoblasts twofold in 2D and 3D assays. Finally, we implanted HGF-loaded, crosslinked (EDCn-HGF) microthreads into a mouse model of VML to evaluate tissue regeneration and functional recovery. Fourteen days post-injury, we observed more muscle ingrowth along EDCn-HGF microthreads than untreated controls, suggesting that released HGF recruited additional progenitor cells to the injury site. Sixty days post-injury, EDCn-HGF microthreads guided mature, organized muscle to replace the microthreads in the wound site. Further, EDCn-HGF microthreads restored the contractile mechanical strength of the tissue to pre-injured values. In summary, we designed fibrin microthreads that recapitulate regenerative cues lost in VML injuries and enhance the functional regeneration of skeletal muscle.

Recently, Magnetic Resonance Imaging (MRI) has found great traction in monitoring the effects of Caloric Restriction (CR) on the brain, specifically gray matter. However, there are no streamlined, simple pipelines in existence to analyze data generated from these kinds of MRI studies. Therefore, my hypothesis is two-fold: the first part being the development of a dynamic and straightforward image processing pipeline, which I have tailored to fit the unique needs of the CR data involved in this study. This data brings me to the second part of my hypothesis, which is to use that pipeline to highlight the decreased attenuation in grey matter induced by long-term CR. In order to test the second portion of my hypothesis, T1/MPRAGE scans were collected from 17 male Rhesus Macaques, half of which were maintained on a 30% reduced calorie diet for an average of 22 years, starting around age 3. Using this basis, the inherent properties of the MR images were exploited by the novel pipeline, and used to analyze whether or not CR reduces the attenuation of grey matter atrophy, with regards to aging

With the wide-spread adoption of exogenous fluorescent indicators – and more recently genetically encoded fluorescent proteins – over the past two decades, there exists a diverse chemical toolkit with which to probe biological systems. Individual cell types and sub-cellular compartments can be targeted in an increasingly wide range of model organisms. However, imaging these samples is often an exercise in balancing the needs of any given experiment against the constraints of the chosen imaging technology. For example, a volume of brain tissue is host to neurons, glia, vascular compartments and red blood cells that all occupy discrete locations in 3D space, but must work together to support healthy organ function. Single-cell activity on the order of milliseconds can trigger downstream processes that unfold over the course of multiple seconds or even minutes. The development of a technique capable of providing depth-resolved, volumetric imaging with scalable spatiotemporal resolution is crucial to developing a proper understanding of such biological systems. Bottlenecks in the throughput of existing technologies stem from a combination of inefficient illumination and volume acquisition strategies, and insufficient sensor read-out speeds. Light sheet microscopy is a promising solution, but individual designs tend to be highly specialized to specific types of samples and do not easily adapt to a wide range of experimental settings. In this thesis, I detail my work in developing swept, confocally-aligned planar excitation (SCAPE) microscopy from a first-generation prototype into a versatile, easy-to-reproduce, easy-to-use system for high-speed, 3D imaging. The first chapter introduces the challenges of designing optical systems capable of high-speed, volumetric imaging. An introduction to design choices faced in the construction of fluorescence microscopes, and current approaches to 3D imaging are discussed. The second chapter describes the progression from the 1st to 2nd generation SCAPE system. Improvements made through ray-tracing models and an enhanced optomechanical design are described, and results from this system in a number of model organisms are presented. The third chapter presents results from a range of biological applications to which SCAPE microscopy has been applied. Work in imaging the zebrafish heart to demonstrate the system’s improved imaging speed, the C. elegans to show the system’s resolution, and finally a number of examples of large field-of-view and high-resolution structural imaging are all described. Finally, the fourth chapter concludes with an overview of the work that lies ahead to both further develop of SCAPE microscopy, as well as to bring the existing system’s strengths to bear in a wider range of environments.

This study compared a manual program for liver volumetry with a semiautomated software. The hypothesis was that the software would be faster, more accurate and less dependent on the evaluator’s experience. Materials and Methods: Ten patients undergoing hemihepatectomy were included into this IRB approved study after written informed consent. All patients underwent a preoperative abdominal CTScan, which was used for whole liver volumetry and volume prediction for the liver part to be resected. Two different softwares were used: 1) manual method: borders of the liver had to be defined per slice by the user; 2) semiautomated software: automatic identification of liver volume with manual assistance for definition of Couinaud-segments. Measurements were done by six observers with different experience levels. Water displacement volumetry immediately after partial liver resection served as gold standard. The resected part was examined with a CT-scan after displacement volumetry. Results: Volumetry of the resected liver scan showed excellent correlations to water displacement volumetry (manual: ρ=0.997; semiautomated software: ρ=0.995). Difference between the predicted volume and the real volume was significantly smaller with the semiautomated software than with the manual method (33 % vs. 57 %, p=0.002). The semiautomated software was almost four times faster for volumetry of the whole liver. Conclusion: Both methods for liver volumetry give an estimated liver volume close to the real one. The tested semiautomated software is faster, more accurate in predicting the volume of the resected liver part, gives more reproducible results and is less dependent on the user’s experience.
Ziel dieser Studie war es, eine manuelle Methode zur Lebervolumetrie mit einer halbautomatischen Software zu vergleichen. Die zu prüfende Hypothese war eine Überlegenheit der halbautomatischen Software hinsichtlich Schnelligkeit, Genauigkeit und Unabhängigkeit von der Erfahrung des Auswerters. Material und Methoden: Die Studie wurde von der Ethikkommission geprüft und es lagen Einverständniserklärungen aller Patienten vor. In die Studie wurden zehn Patienten eingeschlossen, die eine Hemihepatektomie erhielten. Es wurde präoperativ ein CT-Scan angefertigt, der sowohl für die Volumetrie der gesamten Leber als auch zur Bestimmung des Resektatvolumens verwendet wurde. Für die Volumetrie wurden zwei verschiedene Programme genutzt: 1) eine manuelle Methode, wobei die Lebergrenzen in jeder Schicht vom Auswerter definiert werden mussten 2) eine halbautomatische Software mit automatischer Erkennung des Lebervolumens und manueller Definition der Lebersegmente nach Coinaud. Die Messungen wurden von sechs Auswertern mit unterschiedlicher Erfahrung vorgenommen. Als Goldstandard diente eine Verdrängungsvolumetrie des Leberresektats, die direkt nach der Resektion im Operationssaal durchgeführt wurde. Anschließend wurde zusätzlich ein CT-Scan des Resektats angefertigt. Ergebnisse: Die Ergebnisse des postoperativen CT-Scans korrelierten hochgradig mit den Ergebnissen der Verdrängungsvolumetrie (manuell: ρ=0.997; halbautomatische Software: ρ=0.995). Mit der halbautomatischen Software fielen die Unterschiede zwischen dem vorhergesagten und dem tatsächlichen Volumen signifikant kleiner aus (33 % vs. 57 %, p=0.002). Zudem lieferte die halbautomatische Software die Volumina der Gesamtleber 3.9mal schneller. Schlussfolgerung: Beide Methoden erlauben eine sehr gute Abschätzung des Lebervolumens. Die getestete halbautomatische Software kann das Lebervolumen jedoch schneller und das Resektatvolumen genauer vorhersagen und ist zusätzlich unabhängiger von der Erfahrung des Auswerters.

Introdução A colocação de implantes imediatos pós extracionais é uma modalidade de tratamento frequente na prática clínica, sendo objeto de estudo os processos que estão envolvidos na cicatrização do alvéolo, tendo em conta que a inevitabilidade dos fenómenos remodeladores fisiológicos após a extração dentária podem resultar em alterações significativas do osso alveolar. O objetivo deste estudo é comparar as diferenças clínicas determinadas através das alterações tecidulares entre dois tipos de selamento de alvéolos após a colocação de um implante imediato na arcada maxilar, ao longo de dois anos de tratamento. Materiais e Métodos O presente estudo seguiu uma metodologia de estudo clínico prospetivo, controlado, randomizado com paralelismo de grupos de teste. O protocolo de tratamento foi dividido aleatoriamente de acordo com a técnica de fechamento do alvéolo utilizada. Assim, no grupo I foram alocados os pacientes que tiveram o alvéolo pós extracional selado com uma matriz reabsorvível de colagénio suturada através de sutura simples interrompidas com fio de poliamida 6/0 á mucosa alveolar adjacente; os pacientes do grupo II receberam um pilar de cicatrização customizado, sem necessidade de suturas. Todos os pacientes foram reabilitados protética e provisoriamente, com coroa do tipo Maryland. Após dez dias do procedimento cirúrgico, as suturas do grupo I foram removidas e agendados os controlos pós-operatórios, que incluíram visitas a um (T1), quatro (T2), doze (T3) e vinte e quatro (T4) meses após a colocação do implante. Os modelos digitais da arcada em questão correspondentes a T1, T2, T3 e T4 foram exportados do software do scanner ótico intraoral utilizado em formato STL e importados para o programa informático, seguindo o protocolo de análise de modelos já publicados. Os valores médios foram comparados e a significância estatística foi estabelecida a 0,05. X Resultados Participaram neste estudo 34 pacientes, com idade média de 53,38±11,46 anos.. No grupo I, a maioria das alterações dos tecidos ocorreram durante o primeiro (T0-T1), quarto (T0-T2) e décimo segundo mês de observação (T0-T3) em comparação com os vinte quatro meses (T0-T4). Estes resultados não têm significância quando a 1 ano de seguimento em relação as variações das medições lineares como das volumétricas. Relativamente à variação do volume vestibular, as alterações ocorridas nos dois anos de seguimento (T0-T4) os indivíduos do grupo I registavam uma perda média de -8,53%±6,51 e os indivíduos do grupo II de -12,00%±7,09, verificando-se diferenças significativas entre os dois grupos. Conclusão O grupo de pacientes que receberam a membrana de colagénio tem resultados favoráveis ao longo dos dois anos de tratamento na manutenção dos tecidos peri-implantares em relação ao grupo de recebeu o pilar customizado.
Introduction The placement of immediate post-extraction implants is a frequent treatment modality in clinical practice, and the processes that are involved in the healing of the alveolar are being investigated, taking into account that the inevitability of physiological remodeling phenomena after tooth extraction can result in significant changes in alveolar bone. The aim of this study is to compare the clinical differences determined through tissue changes between two types of alveolar sealing after placement of an immediate implant in the maxillary arch over two years of treatment. Materials and Methods The present study followed a methodology of prospective, controlled, randomized clinical study with parallelism of test groups. The treatment protocol was randomly divided according to the alveolus closure technique used. Thus, in group I, patients who had the post-extractional alveolus sealed with a reabsorbable matrix of collagen sutured through a simple suture interrupted with polyamide thread 6/0 to the adjacent alveolar mucosa were allocated; patients in group II received a customized healing abutment, without the need for sutures. All patients were rehabilitated prostheticly and provisionally, with Maryland crown type. Ten days after the surgical procedure, the sutures of group I were removed and scheduled the postoperative controls, which included visits to one (T1), four (T2), twelve (T3) and twenty-four (T4) months after implant insertion. The digital models of the arch in question corresponding to T1, T2, T3 and T4 were exported from the intraoral optical scanner software used in STL format and imported into the computer program, following the analysis protocol of already published models. The mean values were compared and the statistical significance was established at 0.05. Results Thirty-four patients participated in this study, with a mean age of 53.38±11.46 years. No patient was diagnosed with periodontal disease during the 24-month follow-up period. In group I, most tissue changes occurred during the first (T0-T1), fourth (T0-T2) and twelfth month of observation (T0-T3) in comparison with twenty-four months (T0-T4). These results are not significant to XII a 1 year of follow-up in relation to variations in linear measurements and volumetric measurements. Regarding the variation in vestibular volume, the alterations occurred in the two years of follow-up (T0-T4) individuals in group I had an average loss of -8.53%±6.51 and individuals in group II of -12.00%±7.09, with significant differences between the two groups. Conclusion The group of patients who received the collagen membrane had favorable results over the two years of treatment in the maintenance of peri-implant tissues in relation to the customized abutment.

Introdução: Os enxertos de tecido conjuntivo são frequentemente utilizados em procedimentos de recobrimento radicular. Sugere-se a técnica de incisão única, promovendo cicatrização por intenção primária no local dador, estando descrito que poderá induzir menor morbidade pós-operatória ao paciente. Outros propõem o enxerto gengival livre, conferindo melhor visualização do campo operatório e vantagens a nível de espessura gengival. Objetivo: Comparar o padrão de cicatrização do palato após a recolha de enxerto de tecido conjuntivo nos tempos pós-operatórios de 3 e 6 meses através de dois tipos de técnicas de recolha. Materiais e Métodos: Estudo prospetivo de coorte, num período de 6 meses composto por três tempos de avaliação: dia da cirurgia, 3 meses e 6 meses depois da cirurgia. A amostra compreendeu 19 locais de recolha do palato lateral: quatro enxertos subepiteliais (SE) removidos através da técnica “single incision” descrita por Hürzeler MB. & Weng D.; os restantes 15 enxertos desepitelizados (DE) foram removidos através da técnica descrita por Zucchelli, G. et al. O protocolo da avaliação realizou-se através de uma análise digital: efetuaram-se modelos de estudo a cada paciente operado, nos tempos prédefinidos, sendo os mesmos digitalizados com um scanner intraoral (DentalWings®). Nos programas informáticos, Geomagic Control X® e Materialise Magics®, efetuou-se a análise digital tridimensional das áreas intervencionadas. Resultados: Em relação à técnica SE calculou-se uma alteração média da espessura e volume de 0,36mm e 77,52mm3, respetivamente, em T1, e, de -0,10mm e 16,99mm3, respetivamente, em T2. No grupo DE calculou-se uma alteração média da espessura e volume de -0,26mm e 46,99mm3, respetivamente em T1, e, -0,25mm e 50,53mm3, respetivamente, em T2. Conclusões: A recolha de ETC promove alterações a nível dos tecidos moles do palato duro, podendo ocorrer ganho e/ou perda de volume/espessura; aparentam não estabilizar nos primeiros 3 meses, ocorrendo alterações subsequentes. Não existem diferenças significativas entre as técnicas em estudo. A avaliação digital tridimensional demonstrou possuir um carácter inovador, permitindo estudar a dinâmica da cicatrização de tecidos moles.
Introduction: Connective tissue grafts are frequently used in root coverage procedures. Some suggest a single incision technique, promoting primary intention healing at the donor site, probably inducing less postoperative morbidity to the patient. Others propose the free gingival graft, having a better view of the surgical site and advantages in gingival thickness. Aim: To compare the healing pattern in the palate following harvesting of connective tissue graft at 3 and 6 months of postoperative by two different harvesting techniques. Materials and Methods: This is a prospective cohort study, over a period of 6 months. Three evaluation times were made - surgery day (T0), 3 months (T1) and 6 months after surgery (T2). The sample included 19 lateral palatal donor sites. Four subepithelial tissue grafts were harvested using the single incision technique by Hürzeler MB. & Weng D. while the remaining 15 de-epithelialized tissue grafts were harvested using the technique by Zucchelli, G. et al. Digital evaluation protocol: Patient’s casts were recorded at T0, T1 and T2. The casts were digitalized by an intra-oral scanner (DentalWings®). In the computer programs, Geomagic Control X® e Materialise Magics®, the three-dimensional digital analysis of the intervened areas was recorded. Results: Regarding to the SE technique mean thickness and volume change was calculated, getting 0.36mm and 77.52mm3, respectively, at T1, and, 0.10mm and 16.99mm3, respectively, at T2. Regarding to the DE group mean thickness and volume change was calculated, getting -0.26mm and 46.99mm3, respectively, at T1, and, -0.25mm and 50.53mm3, respectively, at T2. Conclusions: ETC harvesting promotes hard palate soft tissues changes and volume/thickness gain or loss may occur; tissue stabilization appears not to happen in the first 3 months, with subsequent changes in place. There appears to be a non-significant tendency for the DE technique to produce minor soft tissue changes comparing to the SE technique. The three-dimensional digital evaluation has shown to be innovative, allowing us to study soft tissue healing dynamics.