Four-dimensional volume-of-interest reconstruction for cone-beam computed tomography-guided radiation therapy.

Science.gov (United States)

Ahmad, Moiz; Balter, Peter; Pan, Tinsu

2011-10-01

Data sufficiency are a major problem in four-dimensional cone-beam computed tomography (4D-CBCT) on linear accelerator-integrated scanners for image-guided radiotherapy. Scan times must be in the range of 4-6 min to avoid undersampling artifacts. Various image reconstruction algorithms have been proposed to accommodate undersampled data acquisitions, but these algorithms are computationally expensive, may require long reconstruction times, and may require algorithm parameters to be optimized. The authors present a novel reconstruction method, 4D volume-of-interest (4D-VOI) reconstruction which suppresses undersampling artifacts and resolves lung tumor motion for undersampled 1-min scans. The 4D-VOI reconstruction is much less computationally expensive than other 4D-CBCT algorithms. The 4D-VOI method uses respiration-correlated projection data to reconstruct a four-dimensional (4D) image inside a VOI containing the moving tumor, and uncorrelated projection data to reconstruct a three-dimensional (3D) image outside the VOI. Anatomical motion is resolved inside the VOI and blurred outside the VOI. The authors acquired a 1-min. scan of an anthropomorphic chest phantom containing a moving water-filled sphere. The authors also used previously acquired 1-min scans for two lung cancer patients who had received CBCT-guided radiation therapy. The same raw data were used to test and compare the 4D-VOI reconstruction with the standard 4D reconstruction and the McKinnon-Bates (MB) reconstruction algorithms. Both the 4D-VOI and the MB reconstructions suppress nearly all the streak artifacts compared with the standard 4D reconstruction, but the 4D-VOI has 3-8 times greater contrast-to-noise ratio than the MB reconstruction. In the dynamic chest phantom study, the 4D-VOI and the standard 4D reconstructions both resolved a moving sphere with an 18 mm displacement. The 4D-VOI reconstruction shows a motion blur of only 3 mm, whereas the MB reconstruction shows a motion blur of 13 mm

An investigation of kV CBCT image quality and dose reduction for volume-of-interest imaging using dynamic collimation

Energy Technology Data Exchange (ETDEWEB)

Parsons, David, E-mail: david.parsons@dal.ca, E-mail: james.robar@cdha.nshealth.ca [Department of Physics and Atmospheric Science, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7 (Canada); Robar, James L., E-mail: david.parsons@dal.ca, E-mail: james.robar@cdha.nshealth.ca [Department of Radiation Oncology and Department of Physics and Atmospheric Science, Dalhousie University, 5820 University Avenue, Halifax, Nova Scotia B3H 1V7 (Canada)

2015-09-15

Purpose: The focus of this work was to investigate the improvements in image quality and dose reduction for volume-of-interest (VOI) kilovoltage-cone beam CT (CBCT) using dynamic collimation. Methods: A prototype iris aperture was used to track a VOI during a CBCT acquisition. The current aperture design is capable of 1D translation as a function of gantry angle and dynamic adjustment of the iris radius. The aperture occupies the location of the bow-tie filter on a Varian On-Board Imager system. CBCT and planar image quality were investigated as a function of aperture radius, while maintaining the same dose to the VOI, for a 20 cm diameter cylindrical water phantom with a 9 mm diameter bone insert centered on isocenter. Corresponding scatter-to-primary ratios (SPR) were determined at the detector plane with Monte Carlo simulation using EGSnrc. Dose distributions for various sizes VOI were modeled using a dynamic BEAMnrc library and DOSXYZnrc. The resulting VOI dose distributions were compared to full-field distributions. Results: SPR was reduced by a factor of 8.4 when decreasing iris diameter from 21.2 to 2.4 cm (at isocenter). Depending upon VOI location and size, dose was reduced to 16%–90% of the full-field value along the central axis plane and down to 4% along the axis of rotation, while maintaining the same dose to the VOI compared to full-field techniques. When maintaining constant dose to the VOI, this change in iris diameter corresponds to a factor increase of approximately 1.6 in image contrast and a factor decrease in image noise of approximately 1.2. This results in a measured gain in contrast-to-noise ratio by a factor of approximately 2.0. Conclusions: The presented VOI technique offers improved image quality for image-guided radiotherapy while sparing the surrounding volume of unnecessary dose compared to full-field techniques.

Cross-cultural adaptation of the Chilean version of the Voice Symptom Scale - VoiSS.

Science.gov (United States)

Ruston, Francisco Contreras; Moreti, Felipe; Vivero, Martín; Malebran, Celina; Behlau, Mara

This research aims to accomplish the cross-cultural equivalence of the Chilean version of the VoiSS protocol through its cultural and linguistic adaptation. After the translation of the VoiSS protocol to Chilean Spanish by two bilingual speech therapists and its back translation to English, we compared the items of the original tool with the previous translated version. The existing discrepancies were modified by a consensus committee of five speech therapists and the translated version was entitled Escala de Sintomas Vocales - ESV, with 30 questions and five answers: "Never", "Occasionally", "Sometimes", "Most of the time", "Always". For cross-cultural equivalence, the protocol was applied to 15 individuals with vocal problems. In each question the option of "Not applicable" was added to the answer choices for identification of the questions not comprehended or not appropriate for the target population. Two individuals had difficulty answering two questions, which made it necessary to adapt the translation of only one of them. The modified ESV was applied to three individuals with vocal problems, and there were incomprehensible inappropriate questions for the Chilean culture. The ESV reflects the original English version, both in the number of questions and the limitations of the emotional and physical domains. There is now a cross-cultural equivalence of VoiSS in Chilean Spanish, titled ESV. The validation of the ESV for Chilean Spanish is ongoing. RESUMEN Este estudio tuvo como objetivo realizar la equivalencia cultural de la versión Chilena del protocolo Voice Symptom Scale - VoiSS por medio de su adaptación cultural y lingüística. Después de la traducción del VoiSS para el Español Chileno, por dos fonoaudiólogos bilingües, y de la retro traducción para el inglés, se realizó una comparación de los ítems del instrumento original con la versión traducida, surgiendo discrepancias; tales divergencias fueron resueltas por un comité compuesto por

Automating the expert consensus paradigm for robust lung tissue classification

Science.gov (United States)

Rajagopalan, Srinivasan; Karwoski, Ronald A.; Raghunath, Sushravya; Bartholmai, Brian J.; Robb, Richard A.

2012-03-01

Clinicians confirm the efficacy of dynamic multidisciplinary interactions in diagnosing Lung disease/wellness from CT scans. However, routine clinical practice cannot readily accomodate such interactions. Current schemes for automating lung tissue classification are based on a single elusive disease differentiating metric; this undermines their reliability in routine diagnosis. We propose a computational workflow that uses a collection (#: 15) of probability density functions (pdf)-based similarity metrics to automatically cluster pattern-specific (#patterns: 5) volumes of interest (#VOI: 976) extracted from the lung CT scans of 14 patients. The resultant clusters are refined for intra-partition compactness and subsequently aggregated into a super cluster using a cluster ensemble technique. The super clusters were validated against the consensus agreement of four clinical experts. The aggregations correlated strongly with expert consensus. By effectively mimicking the expertise of physicians, the proposed workflow could make automation of lung tissue classification a clinical reality.

Stroke infarct volume estimation in fixed tissue

DEFF Research Database (Denmark)

Bay, Vibeke; Kjølby, Birgitte F; Iversen, Nina K

2018-01-01

be investigated in fixed tissue and therefore allows a more direct comparison between lesion volumes from MRI and histology. Additionally, the larger MKT infarct lesion indicates that MKT do provide increased sensitivity to microstructural changes in the lesion area compared to MD....... and prepared. The infarct was clearly visible in both MD and MKT maps. The MKT lesion volume was roughly 31% larger than the MD lesion volume. Subsequent histological analysis (hematoxylin) revealed similar lesion volumes to MD. Our study shows that structural components underlying the MD/MKT mismatch can...

Renal cortical and medullary blood flow responses to altered NO availability in humans.

Science.gov (United States)

Damkjær, Mads; Vafaee, Manoucher; Møller, Michael L; Braad, Poul Erik; Petersen, Henrik; Høilund-Carlsen, Poul Flemming; Bie, Peter

2010-12-01

The objective of this study was to quantify regional renal blood flow in humans. In nine young volunteers on a controlled diet, the lower abdomen was CT-scanned, and regional renal blood flow was determined by positron emission tomography (PET) scanning using H(2)(15)O as tracer. Measurements were performed at baseline, during constant intravenous infusion of nitric oxide (NO) donor glyceryl nitrate and after intravenous injection of NO synthase inhibitor N(ω)-monomethyl-L-arginine (L-NMMA). Using the CT image, the kidney pole areas were delineated as volumes of interest (VOI). In the data analysis, tissue layers with a thickness of one voxel were eliminated stepwise from the external surface of the VOI (voxel peeling), and the blood flow subsequently was determined in each new, reduced VOI. Blood flow in the shrinking VOIs decreased as the number of cycles of voxel peeling increased. After 4-5 cycles, blood flow was not reduced further by additional voxel peeling. This volume-insensitive flow was measured to be 2.30 ± 0.17 ml·g tissue(-1)·min(-1) during the control period; it increased during infusion of glyceryl nitrate to 2.97 ± 0.18 ml·g tissue(-1)·min(-1) (P blood flow was 4.67 ± 0.31 ml·g tissue(-1)·min(-1) during control, unchanged by glyceryl nitrate, and decreased after L-NMMA [3.48 ± 0.23 ml·(g·min)(-1), P renal medullary region in which the measured blood flow is 1) low, 2) independent of reduction in the VOI, and 3) reactive to changes in systemic NO supply. The technique seems to provide indices of renal medullary blood flow in humans.

Automated planning volume definition in soft-tissue sarcoma adjuvant brachytherapy

International Nuclear Information System (INIS)

Lee, Eva K.; Fung, Albert Y.C.; Zaider, Marco; Brooks, J. Paul

2002-01-01

In current practice, the planning volume for adjuvant brachytherapy treatment for soft-tissue sarcoma is either not determined a priori (in this case, seed locations are selected based on isodose curves conforming to a visual estimate of the planning volume), or it is derived via a tedious manual process. In either case, the process is subjective and time consuming, and is highly dependent on the human planner. The focus of the work described herein involves the development of an automated contouring algorithm to outline the planning volume. Such an automatic procedure will save time and provide a consistent and objective method for determining planning volumes. In addition, a definitive representation of the planning volume will allow for sophisticated brachytherapy treatment planning approaches to be applied when designing treatment plans, so as to maximize local tumour control and minimize normal tissue complications. An automated tumour volume contouring algorithm is developed utilizing computational geometry and numerical interpolation techniques in conjunction with an artificial intelligence method. The target volume is defined to be the slab of tissue r cm perpendicularly away from the curvilinear plane defined by the mesh of catheters. We assume that if adjacent catheters are over 2r cm apart, the tissue between the two catheters is part of the tumour bed. Input data consist of the digitized coordinates of the catheter positions in each of several cross-sectional slices of the tumour bed, and the estimated distance r from the catheters to the tumour surface. Mathematically, one can view the planning volume as the volume enclosed within a minimal smoothly-connected surface which contains a set of circles, each circle centred at a given catheter position in a given cross-sectional slice. The algorithm performs local interpolation on consecutive triplets of circles. The effectiveness of the algorithm is evaluated based on its performance on a collection of

Automated planning volume definition in soft-tissue sarcoma adjuvant brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Lee, Eva K. [Department of Radiation Oncology, Emory University School of Medicine, Atlanta, GA (United States); School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Fung, Albert Y.C.; Zaider, Marco [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY (United States); Brooks, J. Paul [School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA (United States)

2002-06-07

In current practice, the planning volume for adjuvant brachytherapy treatment for soft-tissue sarcoma is either not determined a priori (in this case, seed locations are selected based on isodose curves conforming to a visual estimate of the planning volume), or it is derived via a tedious manual process. In either case, the process is subjective and time consuming, and is highly dependent on the human planner. The focus of the work described herein involves the development of an automated contouring algorithm to outline the planning volume. Such an automatic procedure will save time and provide a consistent and objective method for determining planning volumes. In addition, a definitive representation of the planning volume will allow for sophisticated brachytherapy treatment planning approaches to be applied when designing treatment plans, so as to maximize local tumour control and minimize normal tissue complications. An automated tumour volume contouring algorithm is developed utilizing computational geometry and numerical interpolation techniques in conjunction with an artificial intelligence method. The target volume is defined to be the slab of tissue r cm perpendicularly away from the curvilinear plane defined by the mesh of catheters. We assume that if adjacent catheters are over 2r cm apart, the tissue between the two catheters is part of the tumour bed. Input data consist of the digitized coordinates of the catheter positions in each of several cross-sectional slices of the tumour bed, and the estimated distance r from the catheters to the tumour surface. Mathematically, one can view the planning volume as the volume enclosed within a minimal smoothly-connected surface which contains a set of circles, each circle centred at a given catheter position in a given cross-sectional slice. The algorithm performs local interpolation on consecutive triplets of circles. The effectiveness of the algorithm is evaluated based on its performance on a collection of

Interobserver and Intraobserver Reproducibility with Volume Dynamic Contrast Enhanced Computed Tomography (DCE-CT) in Gastroesophageal Junction Cancer

DEFF Research Database (Denmark)

Lundsgaard Hansen, Martin; Fallentin, Eva; Axelsen, Thomas

2016-01-01

-dimensional (2D) fixed ROIs) placed in the tumor periphery, (II) 2-dimensional regions of interest (2D-ROI) along the tumor border in the tumor center, and (III) 3-dimensional volumes of interest (3D-VOI) containing the entire tumor volume. Arterial flow, blood volume and permeability (k(trans)) were recorded...

Quantitative Evaluation of Segmentation- and Atlas-Based Attenuation Correction for PET/MR on Pediatric Patients.

Science.gov (United States)

Bezrukov, Ilja; Schmidt, Holger; Gatidis, Sergios; Mantlik, Frédéric; Schäfer, Jürgen F; Schwenzer, Nina; Pichler, Bernd J

2015-07-01

Pediatric imaging is regarded as a key application for combined PET/MR imaging systems. Because existing MR-based attenuation-correction methods were not designed specifically for pediatric patients, we assessed the impact of 2 potentially influential factors: inter- and intrapatient variability of attenuation coefficients and anatomic variability. Furthermore, we evaluated the quantification accuracy of 3 methods for MR-based attenuation correction without (SEGbase) and with bone prediction using an adult and a pediatric atlas (SEGwBONEad and SEGwBONEpe, respectively) on PET data of pediatric patients. The variability of attenuation coefficients between and within pediatric (5-17 y, n = 17) and adult (27-66 y, n = 16) patient collectives was assessed on volumes of interest (VOIs) in CT datasets for different tissue types. Anatomic variability was assessed on SEGwBONEad/pe attenuation maps by computing mean differences to CT-based attenuation maps for regions of bone tissue, lungs, and soft tissue. PET quantification was evaluated on VOIs with physiologic uptake and on 80% isocontour VOIs with elevated uptake in the thorax and abdomen/pelvis. Inter- and intrapatient variability of the bias was assessed for each VOI group and method. Statistically significant differences in mean VOI Hounsfield unit values and linear attenuation coefficients between adult and pediatric collectives were found in the lungs and femur. The prediction of attenuation maps using the pediatric atlas showed a reduced error in bone tissue and better delineation of bone structure. Evaluation of PET quantification accuracy showed statistically significant mean errors in mean standardized uptake values of -14% ± 5% and -23% ± 6% in bone marrow and femur-adjacent VOIs with physiologic uptake for SEGbase, which could be reduced to 0% ± 4% and -1% ± 5% using SEGwBONEpe attenuation maps. Bias in soft-tissue VOIs was less than 5% for all methods. Lung VOIs showed high SDs in the range of 15% for

Fuzzy hidden Markov chains segmentation for volume determination and quantitation in PET

Energy Technology Data Exchange (ETDEWEB)

Hatt, M [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609 (France); Lamare, F [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609, (France); Boussion, N [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609 (France); Turzo, A [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609 (France); Collet, C [Ecole Nationale Superieure de Physique de Strasbourg (ENSPS), ULP, Strasbourg, F-67000 (France); Salzenstein, F [Institut d' Electronique du Solide et des Systemes (InESS), ULP, Strasbourg, F-67000 (France); Roux, C [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609 (France); Jarritt, P [Medical Physics Agency, Royal Victoria Hospital, Belfast (United Kingdom); Carson, K [Medical Physics Agency, Royal Victoria Hospital, Belfast (United Kingdom); Rest, C Cheze-Le [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609 (France); Visvikis, D [INSERM U650, Laboratoire du Traitement de l' Information Medicale (LaTIM), CHU Morvan, Bat 2bis (I3S), 5 avenue Foch, Brest, 29609 (France)

2007-07-21

Accurate volume of interest (VOI) estimation in PET is crucial in different oncology applications such as response to therapy evaluation and radiotherapy treatment planning. The objective of our study was to evaluate the performance of the proposed algorithm for automatic lesion volume delineation; namely the fuzzy hidden Markov chains (FHMC), with that of current state of the art in clinical practice threshold based techniques. As the classical hidden Markov chain (HMC) algorithm, FHMC takes into account noise, voxel intensity and spatial correlation, in order to classify a voxel as background or functional VOI. However the novelty of the fuzzy model consists of the inclusion of an estimation of imprecision, which should subsequently lead to a better modelling of the 'fuzzy' nature of the object of interest boundaries in emission tomography data. The performance of the algorithms has been assessed on both simulated and acquired datasets of the IEC phantom, covering a large range of spherical lesion sizes (from 10 to 37 mm), contrast ratios (4:1 and 8:1) and image noise levels. Both lesion activity recovery and VOI determination tasks were assessed in reconstructed images using two different voxel sizes (8 mm{sup 3} and 64 mm{sup 3}). In order to account for both the functional volume location and its size, the concept of % classification errors was introduced in the evaluation of volume segmentation using the simulated datasets. Results reveal that FHMC performs substantially better than the threshold based methodology for functional volume determination or activity concentration recovery considering a contrast ratio of 4:1 and lesion sizes of <28 mm. Furthermore differences between classification and volume estimation errors evaluated were smaller for the segmented volumes provided by the FHMC algorithm. Finally, the performance of the automatic algorithms was less susceptible to image noise levels in comparison to the threshold based techniques. The

3D Monte Carlo model of optical transport in laser-irradiated cutaneous vascular malformations

Science.gov (United States)

Majaron, Boris; Milanič, Matija; Jia, Wangcun; Nelson, J. S.

2010-11-01

We have developed a three-dimensional Monte Carlo (MC) model of optical transport in skin and applied it to analysis of port wine stain treatment with sequential laser irradiation and intermittent cryogen spray cooling. Our MC model extends the approaches of the popular multi-layer model by Wang et al.1 to three dimensions, thus allowing treatment of skin inclusions with more complex geometries and arbitrary irradiation patterns. To overcome the obvious drawbacks of either "escape" or "mirror" boundary conditions at the lateral boundaries of the finely discretized volume of interest (VOI), photons exiting the VOI are propagated in laterally infinite tissue layers with appropriate optical properties, until they loose all their energy, escape into the air, or return to the VOI, but the energy deposition outside of the VOI is not computed and recorded. After discussing the selection of tissue parameters, we apply the model to analysis of blood photocoagulation and collateral thermal damage in treatment of port wine stain (PWS) lesions with sequential laser irradiation and intermittent cryogen spray cooling.

Estimating study costs for use in VOI, a study of dutch publicly funded drug related research

NARCIS (Netherlands)

Van Asselt, A.D.; Ramaekers, B.L.; Corro Ramos, I.; Joore, M.A.; Al, M.J.; Lesman-Leegte, I.; Postma, M.J.; Vemer, P.; Feenstra, T.F.

2016-01-01

Objectives: To perform value of information (VOI) analyses, an estimate of research costs is needed. However, reference values for such costs are not available. This study aimed to analyze empirical data on research budgets and, by means of a cost tool, provide an overview of costs of several types

Calculating regional tissue volume for hyperthermic isolated limb perfusion: Four methods compared.

Science.gov (United States)

Cecchin, D; Negri, A; Frigo, A C; Bui, F; Zucchetta, P; Bodanza, V; Gregianin, M; Campana, L G; Rossi, C R; Rastrelli, M

2016-12-01

Hyperthermic isolated limb perfusion (HILP) can be performed as an alternative to amputation for soft tissue sarcomas and melanomas of the extremities. Melphalan and tumor necrosis factor-alpha are used at a dosage that depends on the volume of the limb. Regional tissue volume is traditionally measured for the purposes of HILP using water displacement volumetry (WDV). Although this technique is considered the gold standard, it is time-consuming and complicated to implement, especially in obese and elderly patients. The aim of the present study was to compare the different methods described in the literature for calculating regional tissue volume in the HILP setting, and to validate an open source software. We reviewed the charts of 22 patients (11 males and 11 females) who had non-disseminated melanoma with in-transit metastases or sarcoma of the lower limb. We calculated the volume of the limb using four different methods: WDV, tape measurements and segmentation of computed tomography images using Osirix and Oncentra Masterplan softwares. The overall comparison provided a concordance correlation coefficient (CCC) of 0.92 for the calculations of whole limb volume. In particular, when Osirix was compared with Oncentra (validated for volume measures and used in radiotherapy), the concordance was near-perfect for the calculation of the whole limb volume (CCC = 0.99). With methods based on CT the user can choose a reliable plane for segmentation purposes. CT-based methods also provides the opportunity to separate the whole limb volume into defined tissue volumes (cortical bone, fat and water). Copyright © 2016 Elsevier Ltd. All rights reserved.

Principal component and volume of interest analyses in depressed patients imaged by {sup 99m}Tc-HMPAO SPET: a methodological comparison

Energy Technology Data Exchange (ETDEWEB)

Pagani, Marco [Institute of Cognitive Sciences and Technologies, CNR, Rome (Italy); Section of Nuclear Medicine, Department of Hospital Physics, Karolinska Hospital, Stockholm (Sweden); Gardner, Ann; Haellstroem, Tore [NEUROTEC, Division of Psychiatry, Karolinska Institutet, Huddinge University Hospital, Stockholm (Sweden); Salmaso, Dario [Institute of Cognitive Sciences and Technologies, CNR, Rome (Italy); Sanchez Crespo, Alejandro; Jonsson, Cathrine; Larsson, Stig A. [Section of Nuclear Medicine, Department of Hospital Physics, Karolinska Hospital, Stockholm (Sweden); Jacobsson, Hans [Department of Radiology, Karolinska Hospital, Stockholm (Sweden); Lindberg, Greger [Department of Medicine, Division of Gastroenterology and Hepatology, Karolinska Institutet, Huddinge University Hospital, Stockholm (Sweden); Waegner, Anna [Department of Clinical Neuroscience, Division of Neurology, Karolinska Hospital, Stockholm (Sweden)

2004-07-01

Previous regional cerebral blood flow (rCBF) studies on patients with unipolar major depressive disorder (MDD) have analysed clusters of voxels or single regions and yielded conflicting results, showing either higher or lower rCBF in MDD as compared to normal controls (CTR). The aim of this study was to assess rCBF distribution changes in 68 MDD patients, investigating the data set with both volume of interest (VOI) analysis and principal component analysis (PCA). The rCBF distribution in 68 MDD and 66 CTR, at rest, was compared. Technetium-99m d,l-hexamethylpropylene amine oxime single-photon emission tomography was performed and the uptake in 27 VOIs, bilaterally, was assessed using a standardising brain atlas. Data were then grouped into factors by means of PCA performed on rCBF of all 134 subjects and based on all 54 VOIs. VOI analysis showed a significant group x VOI x hemisphere interaction (P<0.001). rCBF in eight VOIs (in the prefrontal, temporal, occipital and central structures) differed significantly between groups at the P<0.05 level. PCA identified 11 anatomo-functional regions that interacted with groups (P<0.001). As compared to CTR, MDD rCBF was relatively higher in right associative temporo-parietal-occipital cortex (P<0.01) and bilaterally in prefrontal (P<0.005) and frontal cortex (P<0.025), anterior temporal cortex and central structures (P<0.05 and P<0.001 respectively). Higher rCBF in a selected group of MDD as compared to CTR at rest was found using PCA in five clusters of regions sharing close anatomical and functional relationships. At the single VOI level, all eight regions showing group differences were included in such clusters. PCA is a data-driven method for recasting VOIs to be used for group evaluation and comparison. The appearance of significant differences absent at the VOI level emphasises the value of analysing the relationships among brain regions for the investigation of psychiatric disease. (orig.)

Validation of Simple Quantification Methods for (18)F-FP-CIT PET Using Automatic Delineation of Volumes of Interest Based on Statistical Probabilistic Anatomical Mapping and Isocontour Margin Setting.

Science.gov (United States)

Kim, Yong-Il; Im, Hyung-Jun; Paeng, Jin Chul; Lee, Jae Sung; Eo, Jae Seon; Kim, Dong Hyun; Kim, Euishin E; Kang, Keon Wook; Chung, June-Key; Lee, Dong Soo

2012-12-01

(18)F-FP-CIT positron emission tomography (PET) is an effective imaging for dopamine transporters. In usual clinical practice, (18)F-FP-CIT PET is analyzed visually or quantified using manual delineation of a volume of interest (VOI) for the striatum. In this study, we suggested and validated two simple quantitative methods based on automatic VOI delineation using statistical probabilistic anatomical mapping (SPAM) and isocontour margin setting. Seventy-five (18)F-FP-CIT PET images acquired in routine clinical practice were used for this study. A study-specific image template was made and the subject images were normalized to the template. Afterwards, uptakes in the striatal regions and cerebellum were quantified using probabilistic VOI based on SPAM. A quantitative parameter, QSPAM, was calculated to simulate binding potential. Additionally, the functional volume of each striatal region and its uptake were measured in automatically delineated VOI using isocontour margin setting. Uptake-volume product (QUVP) was calculated for each striatal region. QSPAM and QUVP were compared with visual grading and the influence of cerebral atrophy on the measurements was tested. Image analyses were successful in all the cases. Both the QSPAM and QUVP were significantly different according to visual grading (P Simple quantitative measurements of QSPAM and QUVP showed acceptable agreement with visual grading. Although QSPAM in some group may be influenced by cerebral atrophy, these simple methods are expected to be effective in the quantitative analysis of (18)F-FP-CIT PET in usual clinical practice.

TH-A-18C-11: An Investigation of KV CBCT Image Quality and Dose Reduction for Volume-Of-Interest Imaging Using Dynamic Collimation

Energy Technology Data Exchange (ETDEWEB)

Parsons, D [of Physics and Atmospheric Science, Dalhousie University, Halifax, NS (Canada); Robar, J [of Physics and Atmospheric Science, Dalhousie University, Halifax, NS (Canada); Capital District Health Authority, Halifax, NS (Canada)

2014-06-15

Purpose: The focus of this work was to investigate the improvements in image quality and dose reduction for volume-of-interest (VOI) kV-CBCT using dynamic collimation. Methods: A prototype iris aperture was used to track a VOI during a CBCT acquisition. The current aperture design is capable of one-dimensional translation as a function of gantry angle and dynamic adjustment of the iris radius. The aperture occupies the location of the bow-tie filter on a Varian OBI system. CBCT and planar image quality was investigated as a function of aperture radius, while maintaining the same dose to the VOI, for a 20 cm diameter cylindrical water phantom with a 9 mm diameter bone insert centered on isocenter. Corresponding scatter-to-primary ratios (SPR) were determined at the detector plane with Monte Carlo simulation using EGSnrc. Dose distributions for various anatomical sites were modeled using a dynamic BEAMnrc library and DOSXYZnrc. The resulting VOI dose distributions were compared to full-field distributions. Results: SPR was reduced by a factor of 8.4 when decreasing iris diameter from 21.2 cm to 2.4 cm (at isocenter). Similarly, this change in iris diameter corresponds to a factor increase of approximately 1.4 and 1.5 in image contrast for CBCT and planar images, respectively, and similarly a factor decrease in image noise of approximately 1.7 and 1.5. This results in a measured gain in contrast-to-noise ratio of a factor of approximately 2.3 for both CBCT and planar images. Depending upon the anatomical site, dose was reduced to 10%–70% of the full field value along the central axis plane and down to 2% along the axial planes, while maintaining the same dose to the VOI compared to full-field techniques. Conclusion: The presented VOI technique offers improved image quality for image-guided radiotherapy while sparing the surrounding volume of unnecessary dose compared to full-field techniques.

Diagnostic performance of whole brain volume perfusion CT in intra-axial brain tumors: Preoperative classification accuracy and histopathologic correlation

International Nuclear Information System (INIS)

Xyda, Argyro; Haberland, Ulrike; Klotz, Ernst; Jung, Klaus; Bock, Hans Christoph; Schramm, Ramona; Knauth, Michael; Schramm, Peter

2012-01-01

Background: To evaluate the preoperative diagnostic power and classification accuracy of perfusion parameters derived from whole brain volume perfusion CT (VPCT) in patients with cerebral tumors. Methods: Sixty-three patients (31 male, 32 female; mean age 55.6 ± 13.9 years), with MRI findings suspected of cerebral lesions, underwent VPCT. Two readers independently evaluated VPCT data. Volumes of interest (VOIs) were marked circumscript around the tumor according to maximum intensity projection volumes, and then mapped automatically onto the cerebral blood volume (CBV), flow (CBF) and permeability Ktrans perfusion datasets. A second VOI was placed in the contra lateral cortex, as control. Correlations among perfusion values, tumor grade, cerebral hemisphere and VOIs were evaluated. Moreover, the diagnostic power of VPCT parameters, by means of positive and negative predictive value, was analyzed. Results: Our cohort included 32 high-grade gliomas WHO III/IV, 18 low-grade I/II, 6 primary cerebral lymphomas, 4 metastases and 3 tumor-like lesions. Ktrans demonstrated the highest sensitivity, specificity and positive predictive value, with a cut-off point of 2.21 mL/100 mL/min, for both the comparisons between high-grade versus low-grade and low-grade versus primary cerebral lymphomas. However, for the differentiation between high-grade and primary cerebral lymphomas, CBF and CBV proved to have 100% specificity and 100% positive predictive value, identifying preoperatively all the histopathologically proven high-grade gliomas. Conclusion: Volumetric perfusion data enable the hemodynamic assessment of the entire tumor extent and provide a method of preoperative differentiation among intra-axial cerebral tumors with promising diagnostic accuracy.

The volume of fluid injected into the tissue expander and the tissue expansion

Directory of Open Access Journals (Sweden)

Mahmood Omranifard

2014-01-01

Full Text Available Background: Replacement of the lost tissue is the major concerns of the plastic surgeons. Expanded area should be coherent with the surrounding tissue. Tissue expansion technique is the reforming methods the skin tissue scarcities. Several methods for tissue expansion are available; including usage of silicon balloon and injecting fluid into the tissue expander. Materials and Methods: In a clinical trial study, 35 patients, with burn scars, in the face, skull and neck area were studied. We provided a tissue expander device with capacities of 125, 250 and 350cc. Fluid was injected inside the device, 3 consecutive weeks with 1-week interval. After 3 months the device was set out and the tissue expansion was measured using a transparent board and the results were analyzed. Multiple regression was done by SPSS 20 to analyze the data. Results: Regression model showed Skin expansion was positively correlated with the volume of the injected fluid. For each centimeter square of skin expansion, about 6-8 ml of fluid must be injected. Conclusion: Correction of skin defects resulting from burning scar is possible using tissue expanders. The tissue expansion is correlated with the amount of the injected fluid.

Two-Tier VoI Prioritization System on Requirement-Based Data Streaming toward IoT

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Sunyanan Choochotkaew

2017-01-01

Full Text Available Toward the world of Internet of Things, people utilize knowledge from sensor streams in various kinds of smart applications. The number of sensing devices is rapidly increasing along with the amount of sensing data. Consequently, a bottleneck problem at the local gateway has attracted high concern. An example scenario is smart elderly houses in rural areas where each house installs thousands of sensors and all connect to resource-limited and unstable 2G/3G networks. The bottleneck state can incur unacceptable latency and loss of significant data due to the limited waiting-queue. Orthogonally to the existing solutions, we propose a two-tier prioritization system to enhance information quality, indicated by VoI, at the local gateway. The proposed system has been designed to support several requirements with several conflicting criteria over shared sensing streams. Our approach adopts Multicriteria Decision Analysis technique to merge requirements and to assess the VoI. We introduce the framework that can reduce the computational cost by precalculation. Through a case study of building management systems, we have shown that our merge algorithm can provide 0.995 cosine-similarity for representing all user requirements and the evaluation approach can obtain satisfaction values around 3 times higher than the naïve strategies for the top-list data.

Functional imaging of small tissue volumes with diffuse optical tomography

Science.gov (United States)

Klose, Alexander D.; Hielscher, Andreas H.

2006-03-01

Imaging of dynamic changes in blood parameters, functional brain imaging, and tumor imaging are the most advanced application areas of diffuse optical tomography (DOT). When dealing with the image reconstruction problem one is faced with the fact that near-infrared photons, unlike X-rays, are highly scattered when they traverse biological tissue. Image reconstruction schemes are required that model the light propagation inside biological tissue and predict measurements on the tissue surface. By iteratively changing the tissue-parameters until the predictions agree with the real measurements, a spatial distribution of optical properties inside the tissue is found. The optical properties can be related to the tissue oxygenation, inflammation, or to the fluorophore concentration of a biochemical marker. If the model of light propagation is inaccurate, the reconstruction process will lead to an inaccurate result as well. Here, we focus on difficulties that are encountered when DOT is employed for functional imaging of small tissue volumes, for example, in cancer studies involving small animals, or human finger joints for early diagnosis of rheumatoid arthritis. Most of the currently employed image reconstruction methods rely on the diffusion theory that is an approximation to the equation of radiative transfer. But, in the cases of small tissue volumes and tissues that contain low scattering regions diffusion theory has been shown to be of limited applicability Therefore, we employ a light propagation model that is based on the equation of radiative transfer, which promises to overcome the limitations.

The effect of volume-of-interest misregistration on quantitative planar activity and dose estimation

International Nuclear Information System (INIS)

Song, N; Frey, E C; He, B

2010-01-01

In targeted radionuclide therapy (TRT), dose estimation is essential for treatment planning and tumor dose response studies. Dose estimates are typically based on a time series of whole-body conjugate view planar or SPECT scans of the patient acquired after administration of a planning dose. Quantifying the activity in the organs from these studies is an essential part of dose estimation. The quantitative planar (QPlanar) processing method involves accurate compensation for image degrading factors and correction for organ and background overlap via the combination of computational models of the image formation process and 3D volumes of interest defining the organs to be quantified. When the organ VOIs are accurately defined, the method intrinsically compensates for attenuation, scatter and partial volume effects, as well as overlap with other organs and the background. However, alignment between the 3D organ volume of interest (VOIs) used in QPlanar processing and the true organ projections in the planar images is required. The aim of this research was to study the effects of VOI misregistration on the accuracy and precision of organ activity estimates obtained using the QPlanar method. In this work, we modeled the degree of residual misregistration that would be expected after an automated registration procedure by randomly misaligning 3D SPECT/CT images, from which the VOI information was derived, and planar images. Mutual information-based image registration was used to align the realistic simulated 3D SPECT images with the 2D planar images. The residual image misregistration was used to simulate realistic levels of misregistration and allow investigation of the effects of misregistration on the accuracy and precision of the QPlanar method. We observed that accurate registration is especially important for small organs or ones with low activity concentrations compared to neighboring organs. In addition, residual misregistration gave rise to a loss of precision

Estimation of gas and tissue lung volumes by MRI: functional approach of lung imaging.

Science.gov (United States)

Qanadli, S D; Orvoen-Frija, E; Lacombe, P; Di Paola, R; Bittoun, J; Frija, G

1999-01-01

The purpose of this work was to assess the accuracy of MRI for the determination of lung gas and tissue volumes. Fifteen healthy subjects underwent MRI of the thorax and pulmonary function tests [vital capacity (VC) and total lung capacity (TLC)] in the supine position. MR examinations were performed at inspiration and expiration. Lung volumes were measured by a previously validated technique on phantoms. Both individual and total lung volumes and capacities were calculated. MRI total vital capacity (VC(MRI)) was compared with spirometric vital capacity (VC(SP)). Capacities were correlated to lung volumes. Tissue volume (V(T)) was estimated as the difference between the total lung volume at full inspiration and the TLC. No significant difference was seen between VC(MRI) and VC(SP). Individual capacities were well correlated (r = 0.9) to static volume at full inspiration. The V(T) was estimated to be 836+/-393 ml. This preliminary study demonstrates that MRI can accurately estimate lung gas and tissue volumes. The proposed approach appears well suited for functional imaging of the lung.

Gastroenteropancreatic Neuroendocrine Tumors: Standardizing Therapy Monitoring with 68Ga-DOTATOC PET/CT Using the Example of Somatostatin Receptor Radionuclide Therapy

Directory of Open Access Journals (Sweden)

Wolfgang Luboldt

2010-11-01

Full Text Available The purpose of this study was to standardize therapy monitoring of hepatic metastases from gastroenteropancreatic neuroendocrine tumors (GEP-NETs during the course of somatostatin receptor radionuclide therapy (SRRT. In 21 consecutive patients with nonresectable hepatic metastases of GEP-NETs, chromogranin A (CgA and 68Ga-DOTATOC PET/CT were compared before and after the last SRRT. On 68Ga-DOTATOC PET/CT, the maximum standard uptake values (SUVmax of normal liver and hepatic metastases were calculated. In addition, the volumes of hepatic metastases (volume of interest [VOI] were measured using four cut-offs to separate normal liver tissue from metastases (SUVmax of the normal liver plus 10% [VOIliver+10%], 20% [VOIliver+20%], 30% [VOIliver+30%] and SUV = 10 [VOI10SUV]. The SUVmaxof the normal liver was below 10 (7.2 ± 1.3 in all patients and without significant changes. Overall therapy changes (Δ per patient (mean [95% CI] were statistically significant with p < .01 for ΔCgA = −43 (−69 to −17, ΔSUVmax = −22 (−29 to −14, and ΔVOI10SUV = −53 (−68 to −38% and significant with p < .05 for ΔVOIliver+10% = −29 (−55 to −3%, ΔVOIliver+20% = −32 (−62 to −2 and ΔVOIliver+30% = −37 (−66 to −8. Correlations were found only between ΔCgA and ΔVOI10SUV (r = .595; p < .01, ΔSUVmax and ΔVOI10SUV (0.629, p < .01, and SUVmax and ΔSUVmax (r = .446; p < .05. 68Ga-DOTATOC PET/CT allows volumetric therapy monitoring via an SUV-based cut-off separating hepatic metastases from normal liver tissue (10 SUV recommended.

Gross tumor volume and clinical target volume: soft-tissue sarcoma of the extremities

International Nuclear Information System (INIS)

Lartigau, E.; Kantor, G.; Lagarde, P.; Taieb, S.; Ceugnart, L.; Vilain, M.O.; Penel, N.; Depadt, G.

2001-01-01

Soft tissue sarcomas of the extremities are currently treated with more conservative and functional approaches, combining surgery, radiotherapy and chemotherapy. The role of external beam radiotherapy and brachytherapy has been defined through randomized studies performed in the 80's and 90's. However, the ubiquity of tumour location for these tumours makes difficult a systematic definition of local treatments. Tumour volume definition is based on pre and post surgical imaging (MRI) and on described pathological report. The clinical target volume will take into account quality of the resection and anatomical barriers and will be based on an anatomy and not only on safety margins around the tumour bed. General rules for this irradiation (doses, volumes) and principal results will be presented. (authors)

Integral dose and evaluation of irradiated tissue volume

International Nuclear Information System (INIS)

Sivachenko, T.P.; Kalina, V.K.; Belous, A.K.; Gaevskij, V.I.

1984-01-01

Two parameters having potentialities of radiotherapy planning improvement are under consideration. One of these two parameters in an integral dose. An efficiency of application of special tables for integral dose estimation is noted. These tables were developed by the Kiev Physician Improvement Institute and the Cybernetics Institute of the Ukrainian SSR Academy of Science. The meaning of the term of ''irradiated tissue volume'' is specified, and the method of calculation of the irradiated tissue effective mass is considered. It is possible to evaluate with higher accuracy tolerance doses taking into account the irradiated mass

Evaluating differential nuclear DNA yield rates and osteocyte numbers among human bone tissue types: A synchrotron radiation micro-CT approach.

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Andronowski, Janna M; Mundorff, Amy Z; Pratt, Isaac V; Davoren, Jon M; Cooper, David M L

2017-05-01

Molecular human identification has conventionally focused on DNA sampling from dense, weight-bearing cortical bone tissue, typically from femora or tibiae. A comparison of skeletal elements from three contemporary individuals demonstrated that elements with high quantities of cancellous bone yielded nuclear DNA at the highest rates, suggesting that preferentially sampling cortical bone may be suboptimal (Mundorff & Davoren, 2014). Despite these findings, the reason for the differential DNA yields between cortical and cancellous bone tissues remains unknown. The primary goal of this work is to ascertain whether differences in bone microstructure can be used to explain differential nuclear DNA yield among bone tissue types observed by Mundorff and Davoren (2014), with a focus on osteocytes and the three-dimensional (3D) quantification of their associated lacunae. Osteocytes and other bone cells are recognized to house DNA in bone tissue, thus examining the density of their lacunae may explain why nuclear DNA yield rates differ among bone tissue types. Lacunae were visualized and quantified using synchrotron radiation-based micro-Computed Tomographic imaging (SR micro-CT). Volumes of interest (VOIs) from cortical and cancellous bone tissues (n=129) were comparatively analyzed from the three skeletons sampled for Mundorff and Davoren's (2014) study. Analyses tested the primary hypothesis that the abundance and density of osteocytes (inferred from their lacunar spaces) vary between cortical and cancellous bone tissue types. Results demonstrated that osteocyte lacunar abundance and density vary between cortical and cancellous bone tissue types, with cortical bone VOIs containing a higher lacunar abundance and density. We found that the osteocyte lacunar density values are independent of nuclear DNA yield, suggesting an alternative explanation for the higher nuclear DNA yields from bones with greater quantities of cancellous bone tissue. The use of SR micro-CT allowed for

Improved quantification for local regions of interest in preclinical PET imaging

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Cal-González, J.; Moore, S. C.; Park, M.-A.; Herraiz, J. L.; Vaquero, J. J.; Desco, M.; Udias, J. M.

2015-09-01

In Positron Emission Tomography, there are several causes of quantitative inaccuracy, such as partial volume or spillover effects. The impact of these effects is greater when using radionuclides that have a large positron range, e.g. 68Ga and 124I, which have been increasingly used in the clinic. We have implemented and evaluated a local projection algorithm (LPA), originally evaluated for SPECT, to compensate for both partial-volume and spillover effects in PET. This method is based on the use of a high-resolution CT or MR image, co-registered with a PET image, which permits a high-resolution segmentation of a few tissues within a volume of interest (VOI) centered on a region within which tissue-activity values need to be estimated. The additional boundary information is used to obtain improved activity estimates for each tissue within the VOI, by solving a simple inversion problem. We implemented this algorithm for the preclinical Argus PET/CT scanner and assessed its performance using the radionuclides 18F, 68Ga and 124I. We also evaluated and compared the results obtained when it was applied during the iterative reconstruction, as well as after the reconstruction as a postprocessing procedure. In addition, we studied how LPA can help to reduce the ‘spillover contamination’, which causes inaccurate quantification of lesions in the immediate neighborhood of large, ‘hot’ sources. Quantification was significantly improved by using LPA, which provided more accurate ratios of lesion-to-background activity concentration for hot and cold regions. For 18F, the contrast was improved from 3.0 to 4.0 in hot lesions (when the true ratio was 4.0) and from 0.16 to 0.06 in cold lesions (true ratio  =  0.0), when using the LPA postprocessing. Furthermore, activity values estimated within the VOI using LPA during reconstruction were slightly more accurate than those obtained by post-processing, while also visually improving the image contrast and uniformity

Adrenal gland volume, intra-abdominal and pericardial adipose tissue in major depressive disorder.

Science.gov (United States)

Kahl, Kai G; Schweiger, Ulrich; Pars, Kaweh; Kunikowska, Alicja; Deuschle, Michael; Gutberlet, Marcel; Lichtinghagen, Ralf; Bleich, Stefan; Hüper, Katja; Hartung, Dagmar

2015-08-01

Major depressive disorder (MDD) is associated with an increased risk for the development of cardio-metabolic diseases. Increased intra-abdominal (IAT) and pericardial adipose tissue (PAT) have been found in depression, and are discussed as potential mediating factors. IAT and PAT are thought to be the result of a dysregulation of the hypothalamus-pituitary-adrenal axis (HPAA) with subsequent hypercortisolism. Therefore we examined adrenal gland volume as proxy marker for HPAA activation, and IAT and PAT in depressed patients. Twenty-seven depressed patients and 19 comparison subjects were included in this case-control study. Adrenal gland volume, pericardial, intraabdominal and subcutaneous adipose tissue were measured by magnetic resonance imaging. Further parameters included factors of the metabolic syndrome, fasting cortisol, fasting insulin, and proinflammatory cytokines. Adrenal gland and pericardial adipose tissue volumes, serum concentrations of cortisol and insulin, and serum concentrations tumor-necrosis factor-α were increased in depressed patients. Adrenal gland volume was positively correlated with intra-abdominal and pericardial adipose tissue, but not with subcutaneous adipose tissue. Our findings point to the role of HPAA dysregulation and hypercortisolism as potential mediators of IAT and PAT enlargement. Further studies are warranted to examine whether certain subtypes of depression are more prone to cardio-metabolic diseases. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pulmonary tissue volume, cardiac output, and diffusing capacity in sustained microgravity

Science.gov (United States)

Verbanck, S.; Larsson, H.; Linnarsson, D.; Prisk, G. K.; West, J. B.; Paiva, M.

1997-01-01

In microgravity (microG) humans have marked changes in body fluids, with a combination of an overall fluid loss and a redistribution of fluids in the cranial direction. We investigated whether interstitial pulmonary edema develops as a result of a headward fluid shift or whether pulmonary tissue fluid volume is reduced as a result of the overall loss of body fluid. We measured pulmonary tissue volume (Vti), capillary blood flow, and diffusing capacity in four subjects before, during, and after 10 days of exposure to microG during spaceflight. Measurements were made by rebreathing a gas mixture containing small amounts of acetylene, carbon monoxide, and argon. Measurements made early in flight in two subjects showed no change in Vti despite large increases in stroke volume (40%) and diffusing capacity (13%) consistent with increased pulmonary capillary blood volume. Late in-flight measurements in four subjects showed a 25% reduction in Vti compared with preflight controls (P volume, to the extent that it was no longer significantly different from preflight control. Diffusing capacity remained elevated (11%; P pulmonary perfusion and pulmonary capillary blood volume, interstitial pulmonary edema does not result from exposure to microG.

Pancreas segmentation from 3D abdominal CT images using patient-specific weighted subspatial probabilistic atlases

Science.gov (United States)

Karasawa, Kenichi; Oda, Masahiro; Hayashi, Yuichiro; Nimura, Yukitaka; Kitasaka, Takayuki; Misawa, Kazunari; Fujiwara, Michitaka; Rueckert, Daniel; Mori, Kensaku

2015-03-01

Abdominal organ segmentations from CT volumes are now widely used in the computer-aided diagnosis and surgery assistance systems. Among abdominal organs, the pancreas is especially difficult to segment because of its large individual differences of the shape and position. In this paper, we propose a new pancreas segmentation method from 3D abdominal CT volumes using patient-specific weighted-subspatial probabilistic atlases. First of all, we perform normalization of organ shapes in training volumes and an input volume. We extract the Volume Of Interest (VOI) of the pancreas from the training volumes and an input volume. We divide each training VOI and input VOI into some cubic regions. We use a nonrigid registration method to register these cubic regions of the training VOI to corresponding regions of the input VOI. Based on the registration results, we calculate similarities between each cubic region of the training VOI and corresponding region of the input VOI. We select cubic regions of training volumes having the top N similarities in each cubic region. We subspatially construct probabilistic atlases weighted by the similarities in each cubic region. After integrating these probabilistic atlases in cubic regions into one, we perform a rough-to-precise segmentation of the pancreas using the atlas. The results of the experiments showed that utilization of the training volumes having the top N similarities in each cubic region led good results of the pancreas segmentation. The Jaccard Index and the average surface distance of the result were 58.9% and 2.04mm on average, respectively.

Les kystes hydatiques du foie rompus dans les voies biliaires: à propos de 120 cas

Science.gov (United States)

Moujahid, Mountassir; Tajdine, Mohamed Tarik

2011-01-01

Etude rétrospective rapportant une série de kystes hydatiques rompus dans les voies biliaires colligés dans le service de chirurgie de l'hôpital militaire Avicenne à Marrakech. Entre 1990 à 2008, sur 536 kystes hydatiques du foie opérés dans le service, 120 étaient compliqués de rupture dans les voies biliaires soit 22,38%. Il y avait 82hommes et 38 femmes. L’âge moyen était de 35 ans avec des extrêmes allant de 10 à 60 ans. La clinique était dominée par la crise d'angiocholite ou une douleur du flanc droit. L'ictère était isolé dans huit cas. La fistule biliokystique était latente dans plus de 50% des cas. Le traitement a consisté en une résection du dôme saillant dans103cas (85,84%), une périkystectomie chez 11 malades (9,16%) et une lobectomie gauche dans six cas (5%). Le traitement de la fistule bilio kystique a consisté en une suture chez 36malades et un drainage bipolaire dans 25 cas, La déconnexion kysto-biliaire ou cholédocotomie trans hépatico kystique selon Perdomo était pratiquée dans 49cas et une anastomose bilio-digestive cholédoco-duodénale dans 10 cas. La durée moyenne d'hospitalisation était de 20jours. Nous déplorons deux décès par choc septique et un troisième par encéphalopathie secondaire à une cirrhose biliaire. La morbidité était représentée par huit abcès sous phrénique, douze fistules biliaires prolongées et deux occlusions intestinales. Les kystes hydatiques rompus dans les voies biliaires représentent la complication la plus grave de cette pathologie bénigne. Le traitement repose sur des méthodes radicales qui sont d'une efficacité reconnue, mais de réalisation dangereuse et les méthodes conservatrices, en particulier la déconnexion kysto-biliaire qui est une méthode simple et qui donne de bons résultats à court et à long terme. PMID:22384289

Identification d’une nouvelle molécule d’intérêt chez le cheval atteint d’obstruction récurrente des voies respiratoires: La Pentraxine 3

OpenAIRE

Ramery, Eve

2010-01-01

L’ORVR ou obstruction récurrente des voies respiratoires (ORVR) est la cause la plus fréquente de maladie pulmonaire chronique chez le cheval adulte. La maladie se caractérise par une hyperréactivité bronchique, une production excessive de mucus et une inflammation neutrophilique pulmonaire qui ont pour effet de réduire la compliance dynamique du poumon et d’augmenter la résistance des voies respiratoires au débit aérien. Alors que la maladie est une entité documentée dans la littérature depu...

Troglitazone treatment increases bone marrow adipose tissue volume but does not affect trabecular bone volume in mice

DEFF Research Database (Denmark)

Erikstrup, Lise Tornvig; Mosekilde, Leif; Justesen, J

2001-01-01

proliferator activated receptor-gamma (PPARgamma). Histomorphometric analysis of proximal tibia was performed in order to quantitate the amount of trabecular bone volume per total volume (BV/TV %), adipose tissue volume per total volume (AV/TV %), and hematopoietic marrow volume per total volume (HV......Aging is associated with decreased trabecular bone mass and increased adipocyte formation in bone marrow. As osteoblasts and adipocytes share common precursor cells present in the bone marrow stroma, it has been proposed that an inverse relationship exists between adipocyte and osteoblast....../TV %) using the point-counting technique. Bone size did not differ between the two groups. In troglitazone-treated mice, AV/TV was significantly higher than in control mice (4.7+/-2.1% vs. 0.2+/-0.3%, respectively, mean +/- SD, P

Partial volume effect estimation and correction in the aortic vascular wall in PET imaging

International Nuclear Information System (INIS)

Burg, S; Le Guludec, D; Dupas, A; Stute, S; Dieudonné, A; Huet, P; Buvat, I

2013-01-01

We evaluated the impact of partial volume effect (PVE) in the assessment of arterial diseases with 18 FDG PET. An anthropomorphic digital phantom enabling the modeling of aorta related diseases like atherosclerosis and arteritis was used. Based on this phantom, we performed GATE Monte Carlo simulations to produce realistic PET images with a known organ segmentation and ground truth activity values. Images corresponding to 15 different activity-concentration ratios between the aortic wall and the blood and to 7 different wall thicknesses were generated. Using the PET images, we compared the theoretical wall-to-blood activity-concentration ratios (WBRs) with the measured WBRs obtained with five measurement methods: (1) measurement made by a physician (Expert), (2) automated measurement supposed to mimic the physician measurements (Max), (3) simple correction based on a recovery coefficient (Max-RC), (4) measurement based on an ideal VOI segmentation (Mean-VOI) and (5) measurement corrected for PVE using an ideal geometric transfer matrix (GTM) method. We found that Mean-VOI WBRs values were strongly affected by PVE. WBRs obtained by the physician measurement, by the Max method and by the Max-RC method were more accurate than WBRs obtained with the Mean-VOI approach. However Expert, Max and Max-RC WBRs strongly depended on the wall thickness. Only the GTM corrected WBRs did not depend on the wall thickness. Using the GTM method, we obtained more reproducible ratio values that could be compared across wall thickness. Yet, the feasibility of the implementation of a GTM-like method on real data remains to be studied. (paper)

Calculation of normal tissue complication probability and dose-volume histogram reduction schemes for tissues with a critical element architecture

International Nuclear Information System (INIS)

Niemierko, Andrzej; Goitein, Michael

1991-01-01

The authors investigate a model of normal tissue complication probability for tissues that may be represented by a critical element architecture. They derive formulas for complication probability that apply to both a partial volume irradiation and to an arbitrary inhomogeneous dose distribution. The dose-volume isoeffect relationship which is a consequence of a critical element architecture is discussed and compared to the empirical power law relationship. A dose-volume histogram reduction scheme for a 'pure' critical element model is derived. In addition, a point-based algorithm which does not require precomputation of a dose-volume histogram is derived. The existing published dose-volume histogram reduction algorithms are analyzed. The authors show that the existing algorithms, developed empirically without an explicit biophysical model, have a close relationship to the critical element model at low levels of complication probability. However, it is also showed that they have aspects which are not compatible with a critical element model and the authors propose a modification to one of them to circumvent its restriction to low complication probabilities. (author). 26 refs.; 7 figs

Whole body and tissue blood volumes of two strains of rainbow trout (Oncorhynchus mykiss)

Science.gov (United States)

Gingerich, W.H.; Pityer, R.A.; Rach, J.J.

1990-01-01

1. Estimates of apparent packed cell, plasma and total blood volumes for the whole body and for 13 selected tissues were compared between Kamloops and Wytheville strains of rainbow trout (Oncorhynchus mykiss) by the simultaneous injection of two vascular tracers, radiolabeled trout erythrocytes (51Cr-RBC) and radioiodated bovine serum albumin (125I-BSA).2. Whole body total blood volume, plasma volume and packed cell volume were slightly, but not significantly greater in the Wytheville trout, whereas, the apparent plasma volumes and total blood volumes in 4 of 13 tissues were significantly greater in the Kamloops strain.3. Differences were most pronounced in highly perfused organs, such as the liver and kidney and in organs of digestion such as the stomach and intestines.4. Differences in blood volumes between the two strains may be related to the greater permeability of the vascular membranes in the Kamloops strain fish.

Tracking Regional Tissue Volume and Function Change in Lung Using Image Registration

Directory of Open Access Journals (Sweden)

Kunlin Cao

2012-01-01

Full Text Available We have previously demonstrated the 24-hour redistribution and reabsorption of bronchoalveolar lavage (BAL fluid delivered to the lung during a bronchoscopic procedure in normal volunteers. In this work we utilize image-matching procedures to correlate fluid redistribution and reabsorption to changes in regional lung function. Lung CT datasets from six human subjects were used in this study. Each subject was scanned at four time points before and after BAL procedure. Image registration was performed to align images at different time points and different inflation levels. The resulting dense displacement fields were utilized to track tissue volume changes and reveal deformation patterns of local parenchymal tissue quantitatively. The registration accuracy was assessed by measuring landmark matching errors, which were on the order of 1 mm. The results show that quantitative-assessed fluid volume agreed well with bronchoscopist-reported unretrieved BAL volume in the whole lungs (squared linear correlation coefficient was 0.81. The average difference of lung tissue volume at baseline and after 24 hours was around 2%, which indicates that BAL fluid in the lungs was almost absorbed after 24 hours. Regional lung-function changes correlated with the presence of BAL fluid, and regional function returned to baseline as the fluid was reabsorbed.

Absorption and scattering coefficient dependence of laser-Doppler flowmetry models for large tissue volumes

International Nuclear Information System (INIS)

Binzoni, T; Leung, T S; Ruefenacht, D; Delpy, D T

2006-01-01

Based on quasi-elastic scattering theory (and random walk on a lattice approach), a model of laser-Doppler flowmetry (LDF) has been derived which can be applied to measurements in large tissue volumes (e.g. when the interoptode distance is >30 mm). The model holds for a semi-infinite medium and takes into account the transport-corrected scattering coefficient and the absorption coefficient of the tissue, and the scattering coefficient of the red blood cells. The model holds for anisotropic scattering and for multiple scattering of the photons by the moving scatterers of finite size. In particular, it has also been possible to take into account the simultaneous presence of both Brownian and pure translational movements. An analytical and simplified version of the model has also been derived and its validity investigated, for the case of measurements in human skeletal muscle tissue. It is shown that at large optode spacing it is possible to use the simplified model, taking into account only a 'mean' light pathlength, to predict the blood flow related parameters. It is also demonstrated that the 'classical' blood volume parameter, derived from LDF instruments, may not represent the actual blood volume variations when the investigated tissue volume is large. The simplified model does not need knowledge of the tissue optical parameters and thus should allow the development of very simple and cost-effective LDF hardware

Dynamic 2-[18F]fluoro-2-deoxy-d-glucose positron emission tomography of liver tumours without blood sampling

International Nuclear Information System (INIS)

Keiding, S.; Munk, O.L.; Schioett, K.M.; Hansen, S.B.

2000-01-01

Positron emission tomography (PET) using 2-[ 18 F]fluoro-2-deoxy-d-glucose (FDG) is a useful diagnostic tool for the detection of tumours. Using dynamic FDG PET, net metabolic clearance of FDG, K, can be calculated by Gjedde-Patlak analysis of the time course of the radioactivity concentrations in tissue and arterial blood. We examined whether time-activity curves (TACs) based on arterial blood sampling could be replaced by TACs obtained from the descending aorta in dynamic PET scans of patients with liver tumours. The study was performed in two parts, using data from dynamic liver scans with arterial blood sampling in human subjects: First, data from four patients with no liver tumours and five patients with liver tumours were used as a training group. Volumes of interest were defined in the descending aorta (aorta VOIs) by four different methods. K values were calculated based on the corresponding TACs and compared with those based on TACs of the arterial blood sample radioactivity concentrations. The aorta VOI which gave K values that were in best agreement with the K values based on the arterial blood sample measurements was called the AORTA-VOI. Use of the AORTA-VOI was subsequently tested in a test group of 19 tumour patients by comparing the K values from the AORTA-VOI with the K values based on the arterial blood sample measurements. The AORTA-VOI consisted of the sum of small regions of interest (ROIs) drawn in the centre of the aorta (approximately six pixels of 2.4 x 2.4 mm per transaxial slice of 3.1 mm thickness) in as many transaxial slices as possible (30-40 slices). There were no statistically significant differences between the two sets of K values. The ratio of K values in tumour tissue to K values in reference tissue was 2.1-9.7:1 (mean, 5.4:1) based on the AORTA TACs, and 2.1-8.4:1 (mean, 4.6:1) based on blood sample TACs (P>0.3). We conclude that arterial blood sampling can be replaced by the present AORTA-VOI in the calculation of the net

Volume of interest-based [18F]fluorodeoxyglucose PET discriminates MCI converting to Alzheimer's disease from healthy controls. A European Alzheimer's Disease Consortium (EADC study

Directory of Open Access Journals (Sweden)

M. Pagani

2015-01-01

Full Text Available An emerging issue in neuroimaging is to assess the diagnostic reliability of PET and its application in clinical practice. We aimed at assessing the accuracy of brain FDG-PET in discriminating patients with MCI due to Alzheimer's disease and healthy controls. Sixty-two patients with amnestic MCI and 109 healthy subjects recruited in five centers of the European AD Consortium were enrolled. Group analysis was performed by SPM8 to confirm metabolic differences. Discriminant analyses were then carried out using the mean FDG uptake values normalized to the cerebellum computed in 45 anatomical volumes of interest (VOIs in each hemisphere (90 VOIs as defined in the Automated Anatomical Labeling (AAL Atlas and on 12 meta-VOIs, bilaterally, obtained merging VOIs with similar anatomo-functional characteristics. Further, asymmetry indexes were calculated for both datasets. Accuracy of discrimination by a Support Vector Machine (SVM and the AAL VOIs was tested against a validated method (PALZ. At the voxel level SMP8 showed a relative hypometabolism in the bilateral precuneus, and posterior cingulate, temporo-parietal and frontal cortices. Discriminant analysis classified subjects with an accuracy ranging between .91 and .83 as a function of data organization. The best values were obtained from a subset of 6 meta-VOIs plus 6 asymmetry values reaching an area under the ROC curve of .947, significantly larger than the one obtained by the PALZ score. High accuracy in discriminating MCI converters from healthy controls was reached by a non-linear classifier based on SVM applied on predefined anatomo-functional regions and inter-hemispheric asymmetries. Data pre-processing was automated and simplified by an in-house created Matlab-based script encouraging its routine clinical use. Further validation toward nonconverter MCI patients with adequately long follow-up is needed.

Interactive lung segmentation in abnormal human and animal chest CT scans

International Nuclear Information System (INIS)

Kockelkorn, Thessa T. J. P.; Viergever, Max A.; Schaefer-Prokop, Cornelia M.; Bozovic, Gracijela; Muñoz-Barrutia, Arrate; Rikxoort, Eva M. van; Brown, Matthew S.; Jong, Pim A. de; Ginneken, Bram van

2014-01-01

Purpose: Many medical image analysis systems require segmentation of the structures of interest as a first step. For scans with gross pathology, automatic segmentation methods may fail. The authors’ aim is to develop a versatile, fast, and reliable interactive system to segment anatomical structures. In this study, this system was used for segmenting lungs in challenging thoracic computed tomography (CT) scans. Methods: In volumetric thoracic CT scans, the chest is segmented and divided into 3D volumes of interest (VOIs), containing voxels with similar densities. These VOIs are automatically labeled as either lung tissue or nonlung tissue. The automatic labeling results can be corrected using an interactive or a supervised interactive approach. When using the supervised interactive system, the user is shown the classification results per slice, whereupon he/she can adjust incorrect labels. The system is retrained continuously, taking the corrections and approvals of the user into account. In this way, the system learns to make a better distinction between lung tissue and nonlung tissue. When using the interactive framework without supervised learning, the user corrects all incorrectly labeled VOIs manually. Both interactive segmentation tools were tested on 32 volumetric CT scans of pigs, mice and humans, containing pulmonary abnormalities. Results: On average, supervised interactive lung segmentation took under 9 min of user interaction. Algorithm computing time was 2 min on average, but can easily be reduced. On average, 2.0% of all VOIs in a scan had to be relabeled. Lung segmentation using the interactive segmentation method took on average 13 min and involved relabeling 3.0% of all VOIs on average. The resulting segmentations correspond well to manual delineations of eight axial slices per scan, with an average Dice similarity coefficient of 0.933. Conclusions: The authors have developed two fast and reliable methods for interactive lung segmentation in

Monte Carlo simulation of different positron emitting radionuclides incorporated in a soft tissue volume

International Nuclear Information System (INIS)

Olaya D, H.; Martinez O, S. A.; Sevilla M, A. C.; Vega C, H. R.

2015-10-01

Monte Carlo calculations were carried out where compounds with positron-emitters radionuclides, like FDG ( 18 F), Acetate ( 11 C), and Ammonium ( 13 N), were incorporated into a soft tissue volume, in the aim to estimate the type of particles produced their energies, their mean free paths, and the absorbed dose at different distances with respect to the center of the volume. The volume was modeled with a radius larger than the maximum range of positrons in order to produce 0.511 keV annihilation gamma-ray photons. With the obtained results the equivalent dose, in various organs and tissues able to metabolize different radiopharmaceutical drugs, can be estimated. (Author)

Monte Carlo simulation of different positron emitting radionuclides incorporated in a soft tissue volume

Energy Technology Data Exchange (ETDEWEB)

Olaya D, H.; Martinez O, S. A. [Universidad Pedagogica y Tecnologica de Colombia, Grupo de Fisica Nuclear Aplicada y Simulacion, Av. Central del Norte 39-115, 150003 Tunja, Boyaca (Colombia); Sevilla M, A. C. [Universidad Nacional de Colombia, Departamento de Fisica, Grupo CRYOMAG, 111321 Bogota D. C. (Colombia); Vega C, H. R., E-mail: grupo.finuas@uptc.edu.co [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98060 Zacatecas, Zac. (Mexico)

2015-10-15

Monte Carlo calculations were carried out where compounds with positron-emitters radionuclides, like FDG ({sup 18}F), Acetate ({sup 11}C), and Ammonium ({sup 13}N), were incorporated into a soft tissue volume, in the aim to estimate the type of particles produced their energies, their mean free paths, and the absorbed dose at different distances with respect to the center of the volume. The volume was modeled with a radius larger than the maximum range of positrons in order to produce 0.511 keV annihilation gamma-ray photons. With the obtained results the equivalent dose, in various organs and tissues able to metabolize different radiopharmaceutical drugs, can be estimated. (Author)

The cerebrovascular structure and brain tissue volume: a comparative study between beagle dogs and mongrel dogs

International Nuclear Information System (INIS)

Liu Sheng; Shi Haibin; Hu Weixing; Zu Qingquan; Lu Shanshan; Xu Xiaoquan; Sun Lei; Li Linsun

2011-01-01

Objective: To compare the differences of cerebrovascular structure and brain tissue volume between beagle and mongrel dogs by using angiography and MR scanning. Methods: A total of 40 dogs, including 20 beagle dogs (beagle group) and 20 mongrel dogs (mongrel group), were enrolled in this study. Under general anesthesia, all dogs were examined with cerebral angiography and MR scanning. The cerebrovascular structure was evaluated with angiography via selective catheterization of aortic arch, bilateral external cerebral arteries (ECA), maxillary arteries, internal cerebral arteries (ICA) and vertebral arteries separately. The diameters of the ICA, middle cerebral artery (MCA), rostral cerebral artery (RCA), the anastomosis channel ICA and ECA, and basilar artery (BA) were measured at the similar point of each dog. Meanwhile the volumes of the brain tissue were calculated in coronal T2 view of MR scanning. The statistical analysis was performed among the weight of dogs, the diameter of arteries and the volume of brain tissue. The differences in the diameters and brain tissue volume were compared between the two groups. Results: No obvious variations in the cerebrovascular structure and brain tissue volume were found in these dogs. One mongrel dog was excluded from this study because of the severe stenosis of ICA. The mean weight of 20 beagle dogs and 19 mongrel dogs was (12.81±1.29) kg and (12.85±1.12) kg, respectively. The diameters of the ICA, MCA, RCA, the anastomosis channel between ICA and ECA and BA in beagle group were (1.26±0.07) mm, (0.90±0.05) mm, (0.58±0.07) mm, (0.55±0.07) mm and (0.95±0.06) mm, respectively. These parameters in mongrel group were (1.27±0.07) mm, (0.92±0.05) mm, (0.59±0.06) mm, (0.67±0.07) mm and (0.94±0.05) mm, respectively. The volume of brain in two groups was (76232.33±5018.51) mm 3 and (71863.96±4626.87) mm 3 , respectively. There were no obvious correlation among the body weight, the cerebrovascular diameters and brain

Molecular connectivity disruptions in males with major depressive disorder.

Science.gov (United States)

Pillai, Rajapillai Li; Zhang, Mengru; Yang, Jie; Mann, J John; Oquendo, Maria A; Parsey, Ramin V; DeLorenzo, Christine

2018-01-01

In most positron emission tomography (PET) molecular brain imaging studies, regions of interest have been defined anatomically and examined in isolation. However, by defining regions based on physiology and examining relationships between them, we may derive more sensitive measures of receptor abnormalities in conditions such as major depressive disorder (MDD). Using an average of 52 normalized binding potential maps, acquired using radiotracer [ 11 C]-WAY100635 and full arterial input analysis, we identified two molecular volumes of interest (VOIs) with contiguously high serotonin 1A receptor (5-HT 1A ) binding sites: the olfactory sulcus (OLFS) and a band of tissue including piriform, olfactory, and entorhinal cortex (PRF). We applied these VOIs to a separate cohort of 25 healthy control males and 16 males with MDD who received [ 11 C]-WAY100635 imaging. Patients with MDD had significantly higher binding than controls in both VOIs, ( p molecular connectivity, i.e. the correlation between binding of raphe nucleus (RN) 5-HT 1A autoreceptors and post-synaptic receptors in molecular VOIs. Molecular connectivity was significant in healthy controls ( p molecular connectivity allowed identification of MDD cases with high sensitivity (81%) and specificity (88%).

Validation of simple quantification methods for 18F FP CIT PET Using Automatic Delineation of volumes of interest based on statistical probabilistic anatomical mapping and isocontour margin setting

International Nuclear Information System (INIS)

Kim, Yong Il; Im, Hyung Jun; Paeng, Jin Chul; Lee, Jae Sung; Eo, Jae Seon; Kim, Dong Hyun; Kim, Euishin E.; Kang, Keon Wook; Chung, June Key; Lee Dong Soo

2012-01-01

18 F FP CIT positron emission tomography (PET) is an effective imaging for dopamine transporters. In usual clinical practice, 18 F FP CIT PET is analyzed visually or quantified using manual delineation of a volume of interest (VOI) fir the stratum. in this study, we suggested and validated two simple quantitative methods based on automatic VOI delineation using statistical probabilistic anatomical mapping (SPAM) and isocontour margin setting. Seventy five 18 F FP CIT images acquired in routine clinical practice were used for this study. A study-specific image template was made and the subject images were normalized to the template. afterwards, uptakes in the striatal regions and cerebellum were quantified using probabilistic VOI based on SPAM. A quantitative parameter, Q SPAM, was calculated to simulate binding potential. additionally, the functional volume of each striatal region and its uptake were measured in automatically delineated VOI using isocontour margin setting. Uptake volume product(Q UVP) was calculated for each striatal region. Q SPAMa nd Q UVPw as calculated for each visual grading and the influence of cerebral atrophy on the measurements was tested. Image analyses were successful in all the cases. Both the Q SPAMa nd Q UVPw ere significantly different according to visual grading (0.001). The agreements of Q UVPa nd Q SPAMw ith visual grading were slight to fair for the caudate nucleus (K= 0.421 and 0.291, respectively) and good to prefect to the putamen (K=0.663 and 0.607, respectively). Also, Q SPAMa nd Q UVPh ad a significant correlation with each other (0.001). Cerebral atrophy made a significant difference in Q SPAMa nd Q UVPo f the caudate nuclei regions with decreased 18 F FP CIT uptake. Simple quantitative measurements of Q SPAMa nd Q UVPs howed acceptable agreement with visual grad-ing. although Q SPAMi n some group may be influenced by cerebral atrophy, these simple methods are expected to be effective in the quantitative analysis of F FP

Under which conditions, additional monitoring data are worth gathering for improving decision making? Application of the VOI theory in the Bayesian Event Tree eruption forecasting framework

Science.gov (United States)

Loschetter, Annick; Rohmer, Jérémy

2016-04-01

Standard and new generation of monitoring observations provide in almost real-time important information about the evolution of the volcanic system. These observations are used to update the model and contribute to a better hazard assessment and to support decision making concerning potential evacuation. The framework BET_EF (based on Bayesian Event Tree) developed by INGV enables dealing with the integration of information from monitoring with the prospect of decision making. Using this framework, the objectives of the present work are i. to propose a method to assess the added value of information (within the Value Of Information (VOI) theory) from monitoring; ii. to perform sensitivity analysis on the different parameters that influence the VOI from monitoring. VOI consists in assessing the possible increase in expected value provided by gathering information, for instance through monitoring. Basically, the VOI is the difference between the value with information and the value without additional information in a Cost-Benefit approach. This theory is well suited to deal with situations that can be represented in the form of a decision tree such as the BET_EF tool. Reference values and ranges of variation (for sensitivity analysis) were defined for input parameters, based on data from the MESIMEX exercise (performed at Vesuvio volcano in 2006). Complementary methods for sensitivity analyses were implemented: local, global using Sobol' indices and regional using Contribution to Sample Mean and Variance plots. The results (specific to the case considered) obtained with the different techniques are in good agreement and enable answering the following questions: i. Which characteristics of monitoring are important for early warning (reliability)? ii. How do experts' opinions influence the hazard assessment and thus the decision? Concerning the characteristics of monitoring, the more influent parameters are the means rather than the variances for the case considered

External Volume Expansion in Irradiated Tissue: Effects on the Recipient Site.

Science.gov (United States)

Chin, Michael S; Lujan-Hernandez, Jorge; Babchenko, Oksana; Bannon, Elizabeth; Perry, Dylan J; Chappell, Ava G; Lo, Yuan-Chyuan; Fitzgerald, Thomas J; Lalikos, Janice F

2016-05-01

External volume expansion prepares recipient sites to improve outcomes of fat grafting. For patients receiving radiotherapy after mastectomy, results with external volume expansion vary, and the relationship between radiotherapy and expansion remains unexplored. Thus, the authors developed a new translational model to investigate the effects in chronic skin fibrosis after radiation exposure. Twenty-four SKH1-E mice received 50 Gy of β-radiation to each flank and were monitored until fibrosis developed (8 weeks). External volume expansion was then applied at -25 mmHg to one side for 6 hours for 5 days. The opposite side served as the control. Perfusion changes were assessed with hyperspectral imaging. Mice were euthanized at 5 (n = 12) and 15 days (n = 12) after the last expansion application. Tissue samples were analyzed with immunohistochemistry for CD31 and Ki67, Masson trichrome for skin thickness, and picrosirius red to analyze collagen composition. All animals developed skin fibrosis 8 weeks after radiotherapy and became hypoperfused based on hyperspectral imaging. Expansion induced edema on treated sides after stimulation. Perfusion was decreased by 13 percent on the expansion side (p External volume expansion temporarily reduces perfusion, likely because of transient ischemia or edema. Together with mechanotransduction, these effects encourage a proangiogenic and proliferative environment in fibrotic tissue after radiotherapy in the authors' mouse model. Further studies are needed to assess these changes in fat graft retention.

Metabolic liver function measured in vivo by dynamic (18)F-FDGal PET/CT without arterial blood sampling.

Science.gov (United States)

Horsager, Jacob; Munk, Ole Lajord; Sørensen, Michael

2015-01-01

Metabolic liver function can be measured by dynamic PET/CT with the radio-labelled galactose-analogue 2-[(18)F]fluoro-2-deoxy-D-galactose ((18)F-FDGal) in terms of hepatic systemic clearance of (18)F-FDGal (K, ml blood/ml liver tissue/min). The method requires arterial blood sampling from a radial artery (arterial input function), and the aim of this study was to develop a method for extracting an image-derived, non-invasive input function from a volume of interest (VOI). Dynamic (18)F-FDGal PET/CT data from 16 subjects without liver disease (healthy subjects) and 16 patients with liver cirrhosis were included in the study. Five different input VOIs were tested: four in the abdominal aorta and one in the left ventricle of the heart. Arterial input function from manual blood sampling was available for all subjects. K*-values were calculated using time-activity curves (TACs) from each VOI as input and compared to the K-value calculated using arterial blood samples as input. Each input VOI was tested on PET data reconstructed with and without resolution modelling. All five image-derived input VOIs yielded K*-values that correlated significantly with K calculated using arterial blood samples. Furthermore, TACs from two different VOIs yielded K*-values that did not statistically deviate from K calculated using arterial blood samples. A semicircle drawn in the posterior part of the abdominal aorta was the only VOI that was successful for both healthy subjects and patients as well as for PET data reconstructed with and without resolution modelling. Metabolic liver function using (18)F-FDGal PET/CT can be measured without arterial blood samples by using input data from a semicircle VOI drawn in the posterior part of the abdominal aorta.

Quantifying brain tissue volume in multiple sclerosis with automated lesion segmentation and filling

Directory of Open Access Journals (Sweden)

Sergi Valverde

2015-01-01

Full Text Available Lesion filling has been successfully applied to reduce the effect of hypo-intense T1-w Multiple Sclerosis (MS lesions on automatic brain tissue segmentation. However, a study of fully automated pipelines incorporating lesion segmentation and lesion filling on tissue volume analysis has not yet been performed. Here, we analyzed the % of error introduced by automating the lesion segmentation and filling processes in the tissue segmentation of 70 clinically isolated syndrome patient images. First of all, images were processed using the LST and SLS toolkits with different pipeline combinations that differed in either automated or manual lesion segmentation, and lesion filling or masking out lesions. Then, images processed following each of the pipelines were segmented into gray matter (GM and white matter (WM using SPM8, and compared with the same images where expert lesion annotations were filled before segmentation. Our results showed that fully automated lesion segmentation and filling pipelines reduced significantly the % of error in GM and WM volume on images of MS patients, and performed similarly to the images where expert lesion annotations were masked before segmentation. In all the pipelines, the amount of misclassified lesion voxels was the main cause in the observed error in GM and WM volume. However, the % of error was significantly lower when automatically estimated lesions were filled and not masked before segmentation. These results are relevant and suggest that LST and SLS toolboxes allow the performance of accurate brain tissue volume measurements without any kind of manual intervention, which can be convenient not only in terms of time and economic costs, but also to avoid the inherent intra/inter variability between manual annotations.

Basal ganglia volumes in drug-naive first-episode schizophrenia patients before and after short-term treatment with either a typical or an atypical antipsychotic drug

DEFF Research Database (Denmark)

Glenthoj, Andreas; Glenthøj, Birte Yding; Mackeprang, Torben

2007-01-01

or intracranial volume, the only significant difference between patients and controls was a Hemisphere x Group interaction for the caudate nucleus at baseline, with controls having larger left than right caudate nuclei and patients having marginally larger right than left caudate volumes. Within patients, the two...... of exposure to medication and in controls at baseline. Caudate nucleus, nucleus accumbens, and putamen volumes were measured. Compared with controls, absolute volumes of interest (VOIs) were smaller in patients at baseline and increased after treatment. However, with controls for age, gender and whole brain...

Basal ganglia volumes in drug-naive first-episode schizophrenia patients before and after short-term treatment with either a typical or an atypical antipsychotic drug

DEFF Research Database (Denmark)

Glenthoj, Andreas; Glenthoj, Birte Y; Mackeprang, Torben

2007-01-01

of exposure to medication and in controls at baseline. Caudate nucleus, nucleus accumbens, and putamen volumes were measured. Compared with controls, absolute volumes of interest (VOIs) were smaller in patients at baseline and increased after treatment. However, with controls for age, gender and whole brain...... or intracranial volume, the only significant difference between patients and controls was a Hemisphere x Group interaction for the caudate nucleus at baseline, with controls having larger left than right caudate nuclei and patients having marginally larger right than left caudate volumes. Within patients, the two...

Corrections of arterial input function for dynamic H215O PET to assess perfusion of pelvic tumours: arterial blood sampling versus image extraction

International Nuclear Information System (INIS)

Luedemann, L; Sreenivasa, G; Michel, R; Rosner, C; Plotkin, M; Felix, R; Wust, P; Amthauer, H

2006-01-01

Assessment of perfusion with 15 O-labelled water (H 2 15 O) requires measurement of the arterial input function (AIF). The arterial time activity curve (TAC) measured using the peripheral sampling scheme requires corrections for delay and dispersion. In this study, parametrizations with and without arterial spillover correction for fitting of the tissue curve are evaluated. Additionally, a completely noninvasive method for generation of the AIF from a dynamic positron emission tomography (PET) acquisition is applied to assess perfusion of pelvic tumours. This method uses a volume of interest (VOI) to extract the TAC from the femoral artery. The VOI TAC is corrected for spillover using a separate tissue TAC and for recovery by determining the recovery coefficient on a coregistered CT data set. The techniques were applied in five patients with pelvic tumours who underwent a total of 11 examinations. Delay and dispersion correction of the blood TAC without arterial spillover correction yielded in seven examinations solutions inconsistent with physiology. Correction of arterial spillover increased the fitting accuracy and yielded consistent results in all patients. Generation of an AIF from PET image data was investigated as an alternative to arterial blood sampling and was shown to have an intrinsic potential to determine the AIF noninvasively and reproducibly. The AIF extracted from a VOI in a dynamic PET scan was similar in shape to the blood AIF but yielded significantly higher tissue perfusion values (mean of 104.0 ± 52.0%) and lower partition coefficients (-31.6 ± 24.2%). The perfusion values and partition coefficients determined with the VOI technique have to be corrected in order to compare the results with those of studies using a blood AIF

Mineral density volume gradients in normal and diseased human tissues.

Directory of Open Access Journals (Sweden)

Sabra I Djomehri

Full Text Available Clinical computed tomography provides a single mineral density (MD value for heterogeneous calcified tissues containing early and late stage pathologic formations. The novel aspect of this study is that, it extends current quantitative methods of mapping mineral density gradients to three dimensions, discretizes early and late mineralized stages, identifies elemental distribution in discretized volumes, and correlates measured MD with respective calcium (Ca to phosphorus (P and Ca to zinc (Zn elemental ratios. To accomplish this, MD variations identified using polychromatic radiation from a high resolution micro-computed tomography (micro-CT benchtop unit were correlated with elemental mapping obtained from a microprobe X-ray fluorescence (XRF using synchrotron monochromatic radiation. Digital segmentation of tomograms from normal and diseased tissues (N=5 per group; 40-60 year old males contained significant mineral density variations (enamel: 2820-3095 mg/cc, bone: 570-1415 mg/cc, cementum: 1240-1340 mg/cc, dentin: 1480-1590 mg/cc, cementum affected by periodontitis: 1100-1220 mg/cc, hypomineralized carious dentin: 345-1450 mg/cc, hypermineralized carious dentin: 1815-2740 mg/cc, and dental calculus: 1290-1770 mg/cc. A plausible linear correlation between segmented MD volumes and elemental ratios within these volumes was established, and Ca/P ratios for dentin (1.49, hypomineralized dentin (0.32-0.46, cementum (1.51, and bone (1.68 were observed. Furthermore, varying Ca/Zn ratios were distinguished in adapted compared to normal tissues, such as in bone (855-2765 and in cementum (595-990, highlighting Zn as an influential element in prompting observed adaptive properties. Hence, results provide insights on mineral density gradients with elemental concentrations and elemental footprints that in turn could aid in elucidating mechanistic processes for pathologic formations.

Mineral Density Volume Gradients in Normal and Diseased Human Tissues

Science.gov (United States)

Djomehri, Sabra I.; Candell, Susan; Case, Thomas; Browning, Alyssa; Marshall, Grayson W.; Yun, Wenbing; Lau, S. H.; Webb, Samuel; Ho, Sunita P.

2015-01-01

Clinical computed tomography provides a single mineral density (MD) value for heterogeneous calcified tissues containing early and late stage pathologic formations. The novel aspect of this study is that, it extends current quantitative methods of mapping mineral density gradients to three dimensions, discretizes early and late mineralized stages, identifies elemental distribution in discretized volumes, and correlates measured MD with respective calcium (Ca) to phosphorus (P) and Ca to zinc (Zn) elemental ratios. To accomplish this, MD variations identified using polychromatic radiation from a high resolution micro-computed tomography (micro-CT) benchtop unit were correlated with elemental mapping obtained from a microprobe X-ray fluorescence (XRF) using synchrotron monochromatic radiation. Digital segmentation of tomograms from normal and diseased tissues (N=5 per group; 40-60 year old males) contained significant mineral density variations (enamel: 2820-3095mg/cc, bone: 570-1415mg/cc, cementum: 1240-1340mg/cc, dentin: 1480-1590mg/cc, cementum affected by periodontitis: 1100-1220mg/cc, hypomineralized carious dentin: 345-1450mg/cc, hypermineralized carious dentin: 1815-2740mg/cc, and dental calculus: 1290-1770mg/cc). A plausible linear correlation between segmented MD volumes and elemental ratios within these volumes was established, and Ca/P ratios for dentin (1.49), hypomineralized dentin (0.32-0.46), cementum (1.51), and bone (1.68) were observed. Furthermore, varying Ca/Zn ratios were distinguished in adapted compared to normal tissues, such as in bone (855-2765) and in cementum (595-990), highlighting Zn as an influential element in prompting observed adaptive properties. Hence, results provide insights on mineral density gradients with elemental concentrations and elemental footprints that in turn could aid in elucidating mechanistic processes for pathologic formations. PMID:25856386

MR-based automatic delineation of volumes of interest in human brain PET images using probability maps

DEFF Research Database (Denmark)

Svarer, Claus; Madsen, Karina; Hasselbalch, Steen G.

2005-01-01

subjects' MR-images, where VOI sets have been defined manually. High-resolution structural MR-images and 5-HT(2A) receptor binding PET-images (in terms of (18)F-altanserin binding) from 10 healthy volunteers and 10 patients with mild cognitive impairment were included for the analysis. A template including...... 35 VOIs was manually delineated on the subjects' MR images. Through a warping algorithm template VOI sets defined from each individual were transferred to the other subjects MR-images and the voxel overlap was compared to the VOI set specifically drawn for that particular individual. Comparisons were...... delineation of the VOI set. The approach was also shown to work equally well in individuals with pronounced cerebral atrophy. Probability-map-based automatic delineation of VOIs is a fast, objective, reproducible, and safe way to assess regional brain values from PET or SPECT scans. In addition, the method...

Effects of computing parameters and measurement locations on the estimation of 3D NPS in non-stationary MDCT images.

Science.gov (United States)

Miéville, Frédéric A; Bolard, Gregory; Bulling, Shelley; Gudinchet, François; Bochud, François O; Verdun, François R

2013-11-01

The goal of this study was to investigate the impact of computing parameters and the location of volumes of interest (VOI) on the calculation of 3D noise power spectrum (NPS) in order to determine an optimal set of computing parameters and propose a robust method for evaluating the noise properties of imaging systems. Noise stationarity in noise volumes acquired with a water phantom on a 128-MDCT and a 320-MDCT scanner were analyzed in the spatial domain in order to define locally stationary VOIs. The influence of the computing parameters in the 3D NPS measurement: the sampling distances bx,y,z and the VOI lengths Lx,y,z, the number of VOIs NVOI and the structured noise were investigated to minimize measurement errors. The effect of the VOI locations on the NPS was also investigated. Results showed that the noise (standard deviation) varies more in the r-direction (phantom radius) than z-direction plane. A 25 × 25 × 40 mm(3) VOI associated with DFOV = 200 mm (Lx,y,z = 64, bx,y = 0.391 mm with 512 × 512 matrix) and a first-order detrending method to reduce structured noise led to an accurate NPS estimation. NPS estimated from off centered small VOIs had a directional dependency contrary to NPS obtained from large VOIs located in the center of the volume or from small VOIs located on a concentric circle. This showed that the VOI size and location play a major role in the determination of NPS when images are not stationary. This study emphasizes the need for consistent measurement methods to assess and compare image quality in CT. Copyright © 2012 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Association between increased epicardial adipose tissue volume and coronary plaque composition.

Science.gov (United States)

Yamashita, Kennosuke; Yamamoto, Myong Hwa; Ebara, Seitarou; Okabe, Toshitaka; Saito, Shigeo; Hoshimoto, Koichi; Yakushiji, Tadayuki; Isomura, Naoei; Araki, Hiroshi; Obara, Chiaki; Ochiai, Masahiko

2014-09-01

To assess the relationship between epicardial adipose tissue volume (EATV) and plaque vulnerability in significant coronary stenosis using a 40-MHz intravascular ultrasound (IVUS) imaging system (iMap-IVUS), we analyzed 130 consecutive patients with coronary stenosis who underwent dual-source computed tomography (CT) and cardiac catheterization. Culprit lesions were imaged by iMap-IVUS before stenting. The iMAP-IVUS system classified coronary plaque components as fibrous, lipid, necrotic, or calcified tissue, based on the radiofrequency spectrum. Epicardial adipose tissue was measured as the tissue ranging from -190 to -30 Hounsfield units. EATV, calculated as the sum of the fat areas on short-axis images, was 85.0 ± 34.0 cm(3). There was a positive correlation between EATV and the percentage of necrotic plaque tissue (R (2) = 0.34, P EATV and the percentage of fibrous tissue (R (2) = 0.24, P EATV (β = 0.14, P = 0.02) were independently associated with the percentage of necrotic plaque tissue. An increase in EATV was associated with the development of coronary atherosclerosis and, potentially, with the most dangerous type of plaque.

”EI OIKEASSA ELÄMÄSSÄ VOI JUOSTA MIEKKA OJOSSA LOHIKÄÄRMETTÄ KOHTI”: Digipelaajien kokemus omasta hyvinvoinnistaan

OpenAIRE

Engström, Paula

2016-01-01

Paula Engström. ”Ei oikeassa elämässä voi juosta miekka ojossa lohikäärmettä kohti”: Digipelaajien kokemus omasta hyvinvoinnistaan. Diak Etelä, Helsinki, syksy 2016, 57s., 1 liite. Diakonia-ammattikorkeakoulu, Sosiaalialan koulutusohjelma, sosionomi (AMK). Opinnäytetyön aihe syntyi Ehkäisevä päihdetyö EHYT ry:n toiveista saada kooste vuonna 2015 toteutetun Pelaajien hyvinvointikyselyn tuloksista. Opinnäytetyön tavoitteena oli saada selville, miten digitaalisia pelejä harrastavat nuor...

Automated MicroSPECT/MicroCT Image Analysis of the Mouse Thyroid Gland.

Science.gov (United States)

Cheng, Peng; Hollingsworth, Brynn; Scarberry, Daniel; Shen, Daniel H; Powell, Kimerly; Smart, Sean C; Beech, John; Sheng, Xiaochao; Kirschner, Lawrence S; Menq, Chia-Hsiang; Jhiang, Sissy M

2017-11-01

The ability of thyroid follicular cells to take up iodine enables the use of radioactive iodine (RAI) for imaging and targeted killing of RAI-avid thyroid cancer following thyroidectomy. To facilitate identifying novel strategies to improve 131 I therapeutic efficacy for patients with RAI refractory disease, it is desired to optimize image acquisition and analysis for preclinical mouse models of thyroid cancer. A customized mouse cradle was designed and used for microSPECT/CT image acquisition at 1 hour (t1) and 24 hours (t24) post injection of 123 I, which mainly reflect RAI influx/efflux equilibrium and RAI retention in the thyroid, respectively. FVB/N mice with normal thyroid glands and TgBRAF V600E mice with thyroid tumors were imaged. In-house CTViewer software was developed to streamline image analysis with new capabilities, along with display of 3D voxel-based 123 I gamma photon intensity in MATLAB. The customized mouse cradle facilitates consistent tissue configuration among image acquisitions such that rigid body registration can be applied to align serial images of the same mouse via the in-house CTViewer software. CTViewer is designed specifically to streamline SPECT/CT image analysis with functions tailored to quantify thyroid radioiodine uptake. Automatic segmentation of thyroid volumes of interest (VOI) from adjacent salivary glands in t1 images is enabled by superimposing the thyroid VOI from the t24 image onto the corresponding aligned t1 image. The extent of heterogeneity in 123 I accumulation within thyroid VOIs can be visualized by 3D display of voxel-based 123 I gamma photon intensity. MicroSPECT/CT image acquisition and analysis for thyroidal RAI uptake is greatly improved by the cradle and the CTViewer software, respectively. Furthermore, the approach of superimposing thyroid VOIs from t24 images to select thyroid VOIs on corresponding aligned t1 images can be applied to studies in which the target tissue has differential radiotracer retention

The impact of 3D volume of interest definition on accuracy and precision of activity estimation in quantitative SPECT and planar processing methods

Science.gov (United States)

He, Bin; Frey, Eric C.

2010-06-01

Accurate and precise estimation of organ activities is essential for treatment planning in targeted radionuclide therapy. We have previously evaluated the impact of processing methodology, statistical noise and variability in activity distribution and anatomy on the accuracy and precision of organ activity estimates obtained with quantitative SPECT (QSPECT) and planar (QPlanar) processing. Another important factor impacting the accuracy and precision of organ activity estimates is accuracy of and variability in the definition of organ regions of interest (ROI) or volumes of interest (VOI). The goal of this work was thus to systematically study the effects of VOI definition on the reliability of activity estimates. To this end, we performed Monte Carlo simulation studies using randomly perturbed and shifted VOIs to assess the impact on organ activity estimates. The 3D NCAT phantom was used with activities that modeled clinically observed 111In ibritumomab tiuxetan distributions. In order to study the errors resulting from misdefinitions due to manual segmentation errors, VOIs of the liver and left kidney were first manually defined. Each control point was then randomly perturbed to one of the nearest or next-nearest voxels in three ways: with no, inward or outward directional bias, resulting in random perturbation, erosion or dilation, respectively, of the VOIs. In order to study the errors resulting from the misregistration of VOIs, as would happen, e.g. in the case where the VOIs were defined using a misregistered anatomical image, the reconstructed SPECT images or projections were shifted by amounts ranging from -1 to 1 voxels in increments of with 0.1 voxels in both the transaxial and axial directions. The activity estimates from the shifted reconstructions or projections were compared to those from the originals, and average errors were computed for the QSPECT and QPlanar methods, respectively. For misregistration, errors in organ activity estimations were

The impact of 3D volume of interest definition on accuracy and precision of activity estimation in quantitative SPECT and planar processing methods

Energy Technology Data Exchange (ETDEWEB)

He Bin [Division of Nuclear Medicine, Department of Radiology, New York Presbyterian Hospital-Weill Medical College of Cornell University, New York, NY 10021 (United States); Frey, Eric C, E-mail: bih2006@med.cornell.ed, E-mail: efrey1@jhmi.ed [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MD 21287-0859 (United States)

2010-06-21

Accurate and precise estimation of organ activities is essential for treatment planning in targeted radionuclide therapy. We have previously evaluated the impact of processing methodology, statistical noise and variability in activity distribution and anatomy on the accuracy and precision of organ activity estimates obtained with quantitative SPECT (QSPECT) and planar (QPlanar) processing. Another important factor impacting the accuracy and precision of organ activity estimates is accuracy of and variability in the definition of organ regions of interest (ROI) or volumes of interest (VOI). The goal of this work was thus to systematically study the effects of VOI definition on the reliability of activity estimates. To this end, we performed Monte Carlo simulation studies using randomly perturbed and shifted VOIs to assess the impact on organ activity estimates. The 3D NCAT phantom was used with activities that modeled clinically observed {sup 111}In ibritumomab tiuxetan distributions. In order to study the errors resulting from misdefinitions due to manual segmentation errors, VOIs of the liver and left kidney were first manually defined. Each control point was then randomly perturbed to one of the nearest or next-nearest voxels in three ways: with no, inward or outward directional bias, resulting in random perturbation, erosion or dilation, respectively, of the VOIs. In order to study the errors resulting from the misregistration of VOIs, as would happen, e.g. in the case where the VOIs were defined using a misregistered anatomical image, the reconstructed SPECT images or projections were shifted by amounts ranging from -1 to 1 voxels in increments of with 0.1 voxels in both the transaxial and axial directions. The activity estimates from the shifted reconstructions or projections were compared to those from the originals, and average errors were computed for the QSPECT and QPlanar methods, respectively. For misregistration, errors in organ activity estimations

Quantification of brain tissue through incorporation of partial volume effects

Science.gov (United States)

Gage, Howard D.; Santago, Peter, II; Snyder, Wesley E.

1992-06-01

This research addresses the problem of automatically quantifying the various types of brain tissue, CSF, white matter, and gray matter, using T1-weighted magnetic resonance images. The method employs a statistical model of the noise and partial volume effect and fits the derived probability density function to that of the data. Following this fit, the optimal decision points can be found for the materials and thus they can be quantified. Emphasis is placed on repeatable results for which a confidence in the solution might be measured. Results are presented assuming a single Gaussian noise source and a uniform distribution of partial volume pixels for both simulated and actual data. Thus far results have been mixed, with no clear advantage being shown in taking into account partial volume effects. Due to the fitting problem being ill-conditioned, it is not yet clear whether these results are due to problems with the model or the method of solution.

Effects of water immersion to the neck on pulmonary circulation and tissue volume in man

Science.gov (United States)

Begin, R.; Epstein, M.; Sackner, M. A.; Levinson, R.; Dougherty, R.; Duncan, D.

1976-01-01

A rapid noninvasive breathing method is used to obtain serial measurements of the pulmonary capillary blood flow, diffusing capacity per unit of alveolar volume, combined pulmonary tissue plus capillary volume, functional residual capacity, and oxygen consumption in five normal subjects undergoing 6 h of sitting, 4 h of sitting while immersed to the neck in thermoneutral water, and 4 h of lying in thermoneutral water to the neck. The rebreathing method employed a test gas mixture containing 0.5% C2H2, 0.3% C(18)O, 10% He, 21% O2, and balance N2. It is shown that immersion to the neck in the seated posture results in significant increases in sodium excretion cardiac output, and diffusing capacity per unit of alveolar volume. The pulmonary tissue plus capillary volume did not change, demonstrating that the central vascular engorgement induced by water immersion is not accompanied by significant extravasation of fluid into the pulmonary interstitial space.

Automated volume of interest delineation and rendering of cone beam CT images in interventional cardiology

Science.gov (United States)

Lorenz, Cristian; Schäfer, Dirk; Eshuis, Peter; Carroll, John; Grass, Michael

2012-02-01

Interventional C-arm systems allow the efficient acquisition of 3D cone beam CT images. They can be used for intervention planning, navigation, and outcome assessment. We present a fast and completely automated volume of interest (VOI) delineation for cardiac interventions, covering the whole visceral cavity including mediastinum and lungs but leaving out rib-cage and spine. The problem is addressed in a model based approach. The procedure has been evaluated on 22 patient cases and achieves an average surface error below 2mm. The method is able to cope with varying image intensities, varying truncations due to the limited reconstruction volume, and partially with heavy metal and motion artifacts.

Fractionation in normal tissues: the (α/β)eff concept can account for dose heterogeneity and volume effects.

Science.gov (United States)

Hoffmann, Aswin L; Nahum, Alan E

2013-10-07

The simple Linear-Quadratic (LQ)-based Withers iso-effect formula (WIF) is widely used in external-beam radiotherapy to derive a new tumour dose prescription such that there is normal-tissue (NT) iso-effect when changing the fraction size and/or number. However, as conventionally applied, the WIF is invalid unless the normal-tissue response is solely determined by the tumour dose. We propose a generalized WIF (gWIF) which retains the tumour prescription dose, but replaces the intrinsic fractionation sensitivity measure (α/β) by a new concept, the normal-tissue effective fractionation sensitivity, [Formula: see text], which takes into account both the dose heterogeneity in, and the volume effect of, the late-responding normal-tissue in question. Closed-form analytical expressions for [Formula: see text] ensuring exact normal-tissue iso-effect are derived for: (i) uniform dose, and (ii) arbitrary dose distributions with volume-effect parameter n = 1 from the normal-tissue dose-volume histogram. For arbitrary dose distributions and arbitrary n, a numerical solution for [Formula: see text] exhibits a weak dependence on the number of fractions. As n is increased, [Formula: see text] increases from its intrinsic value at n = 0 (100% serial normal-tissue) to values close to or even exceeding the tumour (α/β) at n = 1 (100% parallel normal-tissue), with the highest values of [Formula: see text] corresponding to the most conformal dose distributions. Applications of this new concept to inverse planning and to highly conformal modalities are discussed, as is the effect of possible deviations from LQ behaviour at large fraction sizes.

Ablation of clinically relevant kidney tissue volumes by high-intensity focused ultrasound: Preliminary results of standardized ex-vivo investigations.

Science.gov (United States)

Häcker, Axel; Peters, Kristina; Knoll, Thomas; Marlinghaus, Ernst; Alken, Peter; Jenne, Jürgen W; Michel, Maurice Stephan

2006-11-01

To investigate strategies to achieve confluent kidney-tissue ablation by high-intensity focused ultrasound (HIFU). Our model of the perfused ex-vivo porcine kidney was used. Tissue ablation was performed with an experimental HIFU device (Storz Medical, Kreuzlingen, Switzerland). Lesion-to-lesion interaction was investigated by varying the lesion distance (5 to 2.5 mm), generator power (300, 280, and 260 W), cooling time (10, 20, and 30 seconds), and exposure time (4, 3, and 2 seconds). The lesion rows were analyzed grossly and by histologic examination (hematoxylin-eosin and nicotinamide adenine dinucleotide staining). It was possible to achieve complete homogeneous ablation of a clinically relevant tissue volume but only by meticulous adjustment of the exposure parameters. Minimal changes in these parameters caused changes in lesion formation with holes within the lesions and lesion-to-lesion interaction. Our preliminary results show that when using this new device, HIFU can ablate a large tissue volume homogeneously in perfused ex-vivo porcine tissue under standardized conditions with meticulous adjustment of exposure parameters. Further investigations in vivo are necessary to test whether large tissue volumes can be ablated completely and reliably despite the influence of physiologic tissue and organ movement.

Epicardial adipose tissue volume estimation by postmortem computed tomography of eviscerated hearts

DEFF Research Database (Denmark)

Hindsø, Louise; Jakobsen, Lykke S; Jacobsen, Christina

2017-01-01

Epicardial adipose tissue (EAT) may play a role in the development of coronary artery disease. The purpose of this study was to evaluate a method based on postmortem computed tomography (PMCT) for the estimation of EAT volume. We PMCT-scanned the eviscerated hearts of 144 deceased individuals, wh...

Detection and volume estimation of artificial hematomas in the subcutaneous fatty tissue: comparison of different MR sequences at 3.0 T.

Science.gov (United States)

Ogris, Kathrin; Petrovic, Andreas; Scheicher, Sylvia; Sprenger, Hanna; Urschler, Martin; Hassler, Eva Maria; Yen, Kathrin; Scheurer, Eva

2017-06-01

In legal medicine, reliable localization and analysis of hematomas in subcutaneous fatty tissue is required for forensic reconstruction. Due to the absence of ionizing radiation, magnetic resonance imaging (MRI) is particularly suited to examining living persons with forensically relevant injuries. However, there is limited experience regarding MRI signal properties of hemorrhage in soft tissue. The aim of this study was to evaluate MR sequences with respect to their ability to show high contrast between hematomas and subcutaneous fatty tissue as well as to reliably determine the volume of artificial hematomas. Porcine tissue models were prepared by injecting blood into the subcutaneous fatty tissue to create artificial hematomas. MR images were acquired at 3T and four blinded observers conducted manual segmentation of the hematomas. To assess segmentability, the agreement of measured volume with the known volume of injected blood was statistically analyzed. A physically motivated normalization taking into account partial volume effect was applied to the data to ensure comparable results among differently sized hematomas. The inversion recovery sequence exhibited the best segmentability rate, whereas the T1T2w turbo spin echo sequence showed the most accurate results regarding volume estimation. Both sequences led to reproducible volume estimations. This study demonstrates that MRI is a promising forensic tool to assess and visualize even very small amounts of blood in soft tissue. The presented results enable the improvement of protocols for detection and volume determination of hemorrhage in forensically relevant cases and also provide fundamental knowledge for future in-vivo examinations.

Efficient CT simulation of the four-field technique for conformal radiotherapy of prostate carcinoma

International Nuclear Information System (INIS)

Valicenti, Richard K.; Waterman, Frank M.; Croce, Raymond J.; Corn, Benjamin; Suntharalingam, Nagalingam; Curran, Walter J.

1997-01-01

Purpose: Conformal radiotherapy of prostate carcinoma relies on contouring of individual CT slices for target and normal tissue localization. This process can be very time consuming. In the present report, we describe a method to more efficiently localize pelvic anatomy directly from digital reconstructed radiographs (DRRs). Materials and Methods: Ten patients with prostate carcinoma underwent CT simulation (the spiral mode at 3 mm separation) for conformal four-field 'box' radiotherapy. The bulbous urethra and bladder were opacified with iodinated contrast media. On lateral and anteroposterior DRRs, the volume of interest (VOI) was restricted to 1.0-1.5 cm tissue thickness to optimize digital radiograph reconstruction of the prostate and seminal vesicles. By removing unessential voxel elements, this method provided direct visualization of those structures. For comparison, the targets of each patient were also obtained by contouring CT axial slices. Results: The method was successfully performed if the target structures were readily visualized and geometrically corresponded to those generated by contouring axial images. The targets in 9 of 10 patients were reliable representations of the CT-contoured volumes. One patient had 18 mm variation due to the lack of bladder opacification. Using VOIs to generate thin tissue DRRs, the time required for target and normal tissue localization was on the average less than 5 min. Conclusion: In CT simulation of the four-field irradiation technique for prostate carcinoma, thin-tissue DRRs allowed for efficient and accurate target localization without requiring individual axial image contouring. This method may facilitate positioning of the beam isocenter and provide reliable conformal radiotherapy

A template-based procedure for determining white matter integrity in the internal capsule early after stroke

Directory of Open Access Journals (Sweden)

Matthew A. Petoe

2014-01-01

Full Text Available The integrity of descending white matter pathways, measured by fractional anisotropy from DW-MRI, is a key prognostic indicator of motor recovery after stroke. Barriers to translation of fractional anisotropy measures into routine clinical practice include the time required for manually delineating volumes of interest (VOIs, and inter-examiner variability in this process. This study investigated whether registering and then editing template volumes of interest ‘as required’ would improve inter-examiner reliability compared with manual delineation, without compromising validity. MRI was performed with 30 sub-acute stroke patients with motor deficits (mean NIHSS = 11, range 0–17. Four independent examiners manually delineated VOIs for the posterior limbs of the internal capsules on T1 images, or edited template VOIs that had been registered to the T1 images if they encroached on ventricles or basal ganglia. Fractional anisotropy within each VOI and interhemispheric asymmetry were then calculated. We found that 13/30 registered template VOIs required editing. Edited template VOIs were more spatially similar between examiners than the manually delineated VOIs (p = 0.005. Both methods produced similar asymmetry values that correlated with clinical scores with near perfect levels of agreement between examiners. Contralesional fractional anisotropy correlated with age when edited template VOIs were used but not when VOIs were manually delineated. Editing template VOIs as required is reliable, increases the validity of fractional anisotropy measurements in the posterior limb of the internal capsule, and is less time-consuming compared to manual delineation. This approach could support the use of FA asymmetry measures in routine clinical practice.

Low power digital communication in implantable devices using volume conduction of biological tissues.

Science.gov (United States)

Yao, Ning; Lee, Heung-No; Sclabassi, R J; Sun, Mingui

2006-01-01

This work investigates the data communication problem of implantable devices using fundamental theories in communications. We utilize the volume conduction property of biological tissues to establish a digital communications link. Data obtained through animal experiments are used to analyze the time and frequency response of the volume conduction channel as well as to characterize the biological signals and noises present in the system. A low power bandwidth efficient channel-coded modulation scheme is proposed to conserve battery power and reduce the health risks associated.

Percutaneous bone cement refixation of aseptically loose hip prostheses: the effect of interface tissue removal on injected cement volumes

Energy Technology Data Exchange (ETDEWEB)

Malan, Daniel F. [Leiden University Medical Center, Department of Orthopaedics, Leiden (Netherlands); Delft University of Technology, Department of Intelligent Systems, Delft (Netherlands); Valstar, Edward R. [Leiden University Medical Center, Department of Orthopaedics, Leiden (Netherlands); Delft University of Technology, Department of Biomechanical Engineering, Delft (Netherlands); Nelissen, Rob G.H.H. [Leiden University Medical Center, Department of Orthopaedics, Leiden (Netherlands)

2014-11-15

To quantify whether injected cement volumes differed between two groups of patients who underwent experimental minimally invasive percutaneous cement injection procedures to stabilize aseptically loose hip prostheses. One patient group was preoperatively treated using gene-directed enzyme prodrug therapy to remove fibrous interface tissue, while the other group received no preoperative treatment. It was hypothesized that cement penetration may have been inhibited by the presence of fibrous interface tissue in periprosthetic lesions. We analyzed 17 patients (14 female, 3 male, ages 72-91, ASA categories 2-4) who were treated at our institution. Osteolytic lesions and injected cement were manually delineated using 3D CT image segmentation, and the deposition of injected cement was quantified. Patients who underwent preoperative gene-directed enzyme therapy to remove fibrous tissue exhibited larger injected cement volumes than those who did not. The observed median increase in injected cement volume was 6.8 ml. Higher cement leakage volumes were also observed for this group. We conclude that prior removal of periprosthetic fibrous interface tissue may enable better cement flow and penetration. This might lead to better refixation of aseptically loosened prostheses. (orig.)

Association between increased epicardial adipose tissue volume and coronary plaque composition

OpenAIRE

Yamashita, Kennosuke; Yamamoto, Myong Hwa; Ebara, Seitarou; Okabe, Toshitaka; Saito, Shigeo; Hoshimoto, Koichi; Yakushiji, Tadayuki; Isomura, Naoei; Araki, Hiroshi; Obara, Chiaki; Ochiai, Masahiko

2013-01-01

To assess the relationship between epicardial adipose tissue volume (EATV) and plaque vulnerability in significant coronary stenosis using a 40-MHz intravascular ultrasound (IVUS) imaging system (iMap-IVUS), we analyzed 130 consecutive patients with coronary stenosis who underwent dual-source computed tomography (CT) and cardiac catheterization. Culprit lesions were imaged by iMap-IVUS before stenting. The iMAP-IVUS system classified coronary plaque components as fibrous, lipid, necrotic, or ...

Real-time contrast-enhanced ultrasound determination of microvascular blood volume in abdominal subcutaneous adipose tissue in man. Evidence for adipose tissue capillary recruitment

DEFF Research Database (Denmark)

Tobin, L; Simonsen, L; Bülow, J

2010-01-01

The adipose tissue metabolism is dependent on its blood perfusion. During lipid mobilization e.g. during exercise and during lipid deposition e.g. postprandial, adipose tissue blood flow is increased. This increase in blood flow may involve capillary recruitment in the tissue. We investigated...... of ultrasound contrast agent to establish the reproducibility of the technique. In nine subjects, the effect of an oral glucose load on blood flow and microvascular volume was measured in abdominal subcutaneous adipose tissue and forearm skeletal muscle. ¹³³Xe washout and venous occlusion strain......-gauge plethysmography was used to measure the adipose tissue and forearm blood flow, respectively. Ultrasound signal intensity of the first plateau phases was 27 ± dB in the abdominal subcutaneous adipose tissue and 18 ± 2 dB (P

Single x-ray absorptiometry method for the quantitative mammographic measure of fibroglandular tissue volume

International Nuclear Information System (INIS)

Malkov, Serghei; Wang, Jeff; Kerlikowske, Karla; Cummings, Steven R.; Shepherd, John A.

2009-01-01

Purpose: This study describes the design and characteristics of a highly accurate, precise, and automated single-energy method to quantify percent fibroglandular tissue volume (%FGV) and fibroglandular tissue volume (FGV) using digital screening mammography. Methods: The method uses a breast tissue-equivalent phantom in the unused portion of the mammogram as a reference to estimate breast composition. The phantom is used to calculate breast thickness and composition for each image regardless of x-ray technique or the presence of paddle tilt. The phantom adheres to the top of the mammographic compression paddle and stays in place for both craniocaudal and mediolateral oblique screening views. We describe the automated method to identify the phantom and paddle orientation with a three-dimensional reconstruction least-squares technique. A series of test phantoms, with a breast thickness range of 0.5-8 cm and a %FGV of 0%-100%, were made to test the accuracy and precision of the technique. Results: Using test phantoms, the estimated repeatability standard deviation equaled 2%, with a ±2% accuracy for the entire thickness and density ranges. Without correction, paddle tilt was found to create large errors in the measured density values of up to 7%/mm difference from actual breast thickness. This new density measurement is stable over time, with no significant drifts in calibration noted during a four-month period. Comparisons of %FGV to mammographic percent density and left to right breast %FGV were highly correlated (r=0.83 and 0.94, respectively). Conclusions: An automated method for quantifying fibroglandular tissue volume has been developed. It exhibited good accuracy and precision for a broad range of breast thicknesses, paddle tilt angles, and %FGV values. Clinical testing showed high correlation to mammographic density and between left and right breasts.

Training volume and soft tissue injury in professional and non-professional rugby union players: a systematic review.

Science.gov (United States)

Ball, Shane; Halaki, Mark; Orr, Rhonda

2017-07-01

To investigate the relationship between training volume and soft tissue injury incidence, and characterise soft tissue injury in rugby union players. A systematic search of electronic databases was performed. The search strategy combined terms covering: training volume and injury, and rugby union, and players of all levels. Medline, SPORTDiscus, Web of Science, Embase, PubMed. Studies were included if they reported: male rugby union players, a clear definition of a rugby union injury, the amount of training volume undertaken by participants, and epidemiological data for soft-tissue injuries including the number or incidence. 15 studies were eligible for inclusion. Overall match and training injury incidence ranged from 3.3 to 218.0 injuries/1000 player match hours and 0.1-6.1 injuries/1000 player training hours, respectively. Muscle and tendon as well as joint (non-bone) and ligament injuries were the most frequently occurring injuries. The lower limb was the most prevalent injury location. Injury incidence was higher in professional rugby union players than non-professional players. Contact events were responsible for the greatest injury incidence. For non-contact mechanisms, running was responsible for the highest injury incidence. Inconsistent injury definitions hindered reliable comparison of injury data. The lack of reporting training volumes in hours per player per week limited the ability to investigate associations between training volume and injury incidence. A higher level of play may result in higher match injury incidence. Muscle and tendon injuries were the most common type of soft tissue injury, while the lower limb was the most common location of injury in rugby union players, and running was responsible for the highest injury incidence during non-contact events. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Image-derived input function obtained in a 3TMR-brainPET

Energy Technology Data Exchange (ETDEWEB)

Silva, N.A. da [Institute of Biophysics and Biomedical Engineering, University of Lisbon (Portugal); Institute of Neurosciences and Medicine - 4, Juelich (Germany); Herzog, H., E-mail: h.herzog@fz-juelich.de [Institute of Neurosciences and Medicine - 4, Juelich (Germany); Weirich, C.; Tellmann, L.; Rota Kops, E. [Institute of Neurosciences and Medicine - 4, Juelich (Germany); Hautzel, H. [Department of Nuclear Medicine (KME), University of Duesseldorf, Medical Faculty at Research Center Juelich, Juelich (Germany); Almeida, P. [Institute of Biophysics and Biomedical Engineering, University of Lisbon (Portugal)

2013-02-21

Aim: The combination of a high-resolution MR-compatible BrainPET insert operated within a 3 T MAGNETOM Trio MR scanner is an excellent tool for obtaining an image derived input function (IDIF), due to simultaneous imaging. In this work, we explore the possibility of obtaining an IDIF from volumes of interest (VOI) defined over the carotid arteries (CAs) using the MR data. Material and methods: FDG data from three patients without brain disorders were included. VOIs were drawn bilaterally over the CAs on a MPRAGE image using a 50% isocontour (MR50VOI). CA PET/MR co-registration was examined based on an individual and combined CA co-registration. After that, to estimate the IDIF, the MR50VOI average (IDIF-A), four hottest pixels per plane (IDIF-4H) and four hottest pixels in VOI (IDIF-4V) were considered. A model-based correction for residual partial volume effects involving venous blood samples was applied, from which partial volume (PV) and spillover (SP) coefficients were estimated. Additionally, a theoretical PV coefficient (PVt) was calculated based on MR50VOI. Results: The results show an excellent co-registration between the MR and PET, with an area under the curve ratio between both co-registration methods of 1.00±0.04. A good agreement between PV and PVt was found for IDIF-A, with PV of 0.39±0.06 and PVt 0.40±0.03, and for IDIF-4H, with PV of 0.47±0.05 and PVt 0.47±0.03. The SPs were 0.20±0.03 and 0.21±0.03 for IDIF-A and IDIF-4H, respectively. Conclusion: The integration of a high resolution BrainPET in an MR scanner allows to obtain an IDIF from an MR-based VOI. This must be corrected for a residual partial volume effect.

Global brain metabolic quantification with whole-head proton MRS at 3 T.

Science.gov (United States)

Kirov, Ivan I; Wu, William E; Soher, Brian J; Davitz, Matthew S; Huang, Jeffrey H; Babb, James S; Lazar, Mariana; Fatterpekar, Girish; Gonen, Oded

2017-10-01

Total N-acetyl-aspartate + N-acetyl-aspartate-glutamate (NAA), total creatine (Cr) and total choline (Cho) proton MRS ( 1 H-MRS) signals are often used as surrogate markers in diffuse neurological pathologies, but spatial coverage of this methodology is limited to 1%-65% of the brain. Here we wish to demonstrate that non-localized, whole-head (WH) 1 H-MRS captures just the brain's contribution to the Cho and Cr signals, ignoring all other compartments. Towards this end, 27 young healthy adults (18 men, 9 women), 29.9 ± 8.5 years old, were recruited and underwent T 1 -weighted MRI for tissue segmentation, non-localizing, approximately 3 min WH 1 H-MRS (T E /T R /T I  = 5/10/940 ms) and 30 min 1 H-MR spectroscopic imaging (MRSI) (T E /T R  = 35/2100 ms) in a 360 cm 3 volume of interest (VOI) at the brain's center. The VOI absolute NAA, Cr and Cho concentrations, 7.7 ± 0.5, 5.5 ± 0.4 and 1.3 ± 0.2 mM, were all within 10% of the WH: 8.6 ± 1.1, 6.0 ± 1.0 and 1.3 ± 0.2 mM. The mean NAA/Cr and NAA/Cho ratios in the WH were only slightly higher than the "brain-only" VOI: 1.5 versus 1.4 (7%) and 6.6 versus 5.9 (11%); Cho/Cr were not different. The brain/WH volume ratio was 0.31 ± 0.03 (brain ≈ 30% of WH volume). Air-tissue susceptibility-driven local magnetic field changes going from the brain outwards showed sharp gradients of more than 100 Hz/cm (1 ppm/cm), explaining the skull's Cr and Cho signal losses through resonance shifts, line broadening and destructive interference. The similarity of non-localized WH and localized VOI NAA, Cr and Cho concentrations and their ratios suggests that their signals originate predominantly from the brain. Therefore, the fast, comprehensive WH- 1 H-MRS method may facilitate quantification of these metabolites, which are common surrogate markers in neurological disorders. Copyright © 2017 John Wiley & Sons, Ltd.

Adipose tissue depot volume relationships with spinal trabecular bone mineral density in African Americans with diabetes.

Directory of Open Access Journals (Sweden)

Gary C Chan

Full Text Available Changes in select adipose tissue volumes may differentially impact bone mineral density. This study was performed to assess cross-sectional and longitudinal relationships between computed tomography-determined visceral (VAT, subcutaneous (SAT, inter-muscular (IMAT, and pericardial adipose tissue (PAT volumes with respective changes in thoracic vertebral and lumbar vertebral volumetric trabecular bone mineral density (vBMD in African Americans with type 2 diabetes. Generalized linear models were fitted to test relationships between baseline and change in adipose volumes with change in vBMD in 300 African American-Diabetes Heart Study participants; adjustment was performed for age, sex, diabetes duration, study interval, smoking, hypertension, BMI, kidney function, and medications. Participants were 50% female with mean ± SD age 55.1±9.0 years, diabetes duration 10.2±7.2 years, and BMI 34.7±7.7 kg/m2. Over 5.3 ± 1.4 years, mean vBMD decreased in thoracic/lumbar spine, while mean adipose tissue volumes increased in SAT, IMAT, and PAT, but not VAT depots. In fully-adjusted models, changes in lumbar and thoracic vBMD were positively associated with change in SAT (β[SE] 0.045[0.011], p<0.0001; 0.40[0.013], p = 0.002, respectively. Change in thoracic vBMD was positively associated with change in IMAT (p = 0.029 and VAT (p = 0.016; and change in lumbar vBMD positively associated with baseline IMAT (p<0.0001. In contrast, vBMD was not associated with change in PAT. After adjusting for BMI, baseline and change in volumes of select adipose depots were associated with increases in thoracic and lumbar trabecular vBMD in African Americans. Effects of adiposity on trabecular bone appear to be site-specific and related to factors beyond mechanical load.

Brain tissues volume measurements from 2D MRI using parametric approach

Science.gov (United States)

L'vov, A. A.; Toropova, O. A.; Litovka, Yu. V.

2018-04-01

The purpose of the paper is to propose a fully automated method of volume assessment of structures within human brain. Our statistical approach uses maximum interdependency principle for decision making process of measurements consistency and unequal observations. Detecting outliers performed using maximum normalized residual test. We propose a statistical model which utilizes knowledge of tissues distribution in human brain and applies partial data restoration for precision improvement. The approach proposes completed computationally efficient and independent from segmentation algorithm used in the application.

Volume fractions of DCE-MRI parameter as early predictor of histologic response in soft tissue sarcoma: A feasibility study.

Science.gov (United States)

Xia, Wei; Yan, Zhuangzhi; Gao, Xin

2017-10-01

To find early predictors of histologic response in soft tissue sarcoma through volume transfer constant (K trans ) analysis based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). 11 Patients with soft tissue sarcoma of the lower extremity that underwent preoperative chemoradiotherapy followed by limb salvage surgery were included in this retrospective study. For each patient, DCE-MRI data sets were collected before and two weeks after therapy initiation, and histologic tumor cell necrosis rate (TCNR) was reported at surgery. The DCE-MRI volumes were aligned by registration. Then, the aligned volumes were used to obtain the K trans variation map. Accordingly, three sub-volumes (with increased, decreased or unchanged K trans ) were defined and identified, and fractions of the sub-volumes, denoted as F + , F - and F 0 , respectively, were calculated. The predictive ability of volume fractions was determined by using area under a receiver operating characteristic curve (AUC). Linear regression analysis was performed to investigate the relationship between TCNR and volume fractions. In addition, the K trans values of the sub-volumes were compared. The AUC for F - (0.896) and F 0 (0.833) were larger than that for change of tumor longest diameter ΔD (0.625) and the change of mean K trans ΔK trans ¯ (0.792). Moreover, the regression results indicated that TCNR was directly proportional to F 0 (R 2 =0.75, P=0.0003), while it was inversely proportional to F - (R 2 =0.77, P=0.0002). However, TCNR had relatively weak linear relationship with ΔK trans ¯ (R 2 =0.64, P=0.0018). Additionally, TCNR did not have linear relationship with DD (R 2 =0.16, P=0.1246). The volume fraction F - and F 0 have potential as early predictors of soft tissue sarcoma histologic response. Copyright © 2017 Elsevier B.V. All rights reserved.

Revisiting the Logan plot to account for non-negligible blood volume in brain tissue.

Science.gov (United States)

Schain, Martin; Fazio, Patrik; Mrzljak, Ladislav; Amini, Nahid; Al-Tawil, Nabil; Fitzer-Attas, Cheryl; Bronzova, Juliana; Landwehrmeyer, Bernhard; Sampaio, Christina; Halldin, Christer; Varrone, Andrea

2017-08-18

Reference tissue-based quantification of brain PET data does not typically include correction for signal originating from blood vessels, which is known to result in biased outcome measures. The bias extent depends on the amount of radioactivity in the blood vessels. In this study, we seek to revisit the well-established Logan plot and derive alternative formulations that provide estimation of distribution volume ratios (DVRs) that are corrected for the signal originating from the vasculature. New expressions for the Logan plot based on arterial input function and reference tissue were derived, which included explicit terms for whole blood radioactivity. The new methods were evaluated using PET data acquired using [ 11 C]raclopride and [ 18 F]MNI-659. The two-tissue compartment model (2TCM), with which signal originating from blood can be explicitly modeled, was used as a gold standard. DVR values obtained for [ 11 C]raclopride using the either blood-based or reference tissue-based Logan plot were systematically underestimated compared to 2TCM, and for [ 18 F]MNI-659, a proportionality bias was observed, i.e., the bias varied across regions. The biases disappeared when optimal blood-signal correction was used for respective tracer, although for the case of [ 18 F]MNI-659 a small but systematic overestimation of DVR was still observed. The new method appears to remove the bias introduced due to absence of correction for blood volume in regular graphical analysis and can be considered in clinical studies. Further studies are however required to derive a generic mapping between plasma and whole-blood radioactivity levels.

Considerations of anthropometric, tissue volume, and tissue mass scaling for improved patient specificity of skeletal S values

International Nuclear Information System (INIS)

Bolch, W.E.; Patton, P.W.; Shah, A.P.; Rajon, D.A.; Jokisch, D.W.

2002-01-01

It is generally acknowledged that reference man (70 kg in mass and 170 cm in height) does not adequately represent the stature and physical dimensions of many patients undergoing radionuclide therapy, and thus scaling of radionuclide S values is required for patient specificity. For electron and beta sources uniformly distributed within internal organs, the mean dose from self-irradiation is noted to scale inversely with organ mass, provided no escape of electron energy occurs at the organ boundaries. In the skeleton, this same scaling approach is further assumed to be correct for marrow dosimetry; nevertheless, difficulties in quantitative assessments of marrow mass in specific skeletal regions of the patient make this approach difficult to implement clinically. Instead, scaling of marrow dose is achieved using various anthropometric parameters that presumably scale in the same proportion. In this study, recently developed three-dimensional macrostructural transport models of the femoral head and humeral epiphysis in three individuals (51-year male, 82-year female, and 86-year female) are used to test the abilities of different anthropometric parameters (total body mass, body surface area, etc.) to properly scale radionuclide S values from reference man models. The radionuclides considered are 33 P, 177 Lu, 153 Sm, 186 Re, 89 Sr, 166 Ho, 32 P, 188 Re, and 90 Y localized in either the active marrow or endosteal tissues of the bone trabeculae. S value scaling is additionally conducted in which the 51-year male subject is assigned as the reference individual; scaling parameters are then expanded to include tissue volumes and masses for both active marrow and skeletal spongiosa. The study concludes that, while no single anthropometric parameter emerges as a consistent scaler of reference man S values, lean body mass is indicated as an optimal scaler when the reference S values are based on 3D transport techniques. Furthermore, very exact patient-specific scaling of

SU-F-T-150: Comparing Normal Tissue Irradiated Volumes for Proton Vs. Photon Treatment Plans On Lung Patients

Energy Technology Data Exchange (ETDEWEB)

Liu, A; Mohan, R; Liao, Z [UT MD Anderson Cancer Center, Houston, TX (United States)

2016-06-15

Purpose: The aim of this work is to compare the “irradiated volume” (IRV) of normal tissues receiving 5, 20, 50, 80 and 90% or higher of the prescription dose with passively scattered proton therapy (PSPT) vs. IMRT of lung cancer patients. The overall goal of this research is to understand the factors affecting outcomes of a randomized PSPT vs. IMRT lung trial. Methods: Thirteen lung cancer patients, selected randomly, were analyzed. Each patient had PSPT and IMRT 74 Gy (RBE) plans meeting the same normal tissue constraints generated. IRVs were created for pairs of IMRT and PSPT plans on each patient. The volume of iGTV, (respiratory motion-incorporated GTV) was subtracted from each IRV to create normal tissue irradiated volume IRVNT. The average of IRVNT DVHs over all patients was also calculated for both modalities and inter-compared as were the selected dose-volume indices. Probability (p value) curves were calculated based on the Wilcoxon matched-paired signed-rank test to determine the dose regions where the statistically significant differences existed. Results: As expected, the average 5, 20 and 50% IRVNT’s for PSPT was found to be significantly smaller than for IMRT (p < 0.001, 0.01, and 0.001 respectively). However, the average 90% IRVNT for PSPT was greater than for IMRT (p = 0.003) presumably due to larger penumbra of protons and the long range of protons in lower density media. The 80% IRVNT for PSPT was also larger but not statistically distinguishable (p = .224). Conclusion: PSPT modality has smaller irradiated volume at lower doses, but larger volume at high doses. A larger cohort of lung patients will be analyzed in the future and IRVNT of patients treated with PSPT and IMRT will be compared to determine if the irradiated volumes (the magnitude of “dose bath”) correlate with outcomes.

Determination of quantitative tissue composition by iterative reconstruction on 3D DECT volumes

Energy Technology Data Exchange (ETDEWEB)

Magnusson, Maria [Linkoeping Univ. (Sweden). Dept. of Electrical Engineering; Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Linkoeping Univ. (Sweden). Center for Medical Image Science and Visualization (CMIV); Malusek, Alexandr [Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Linkoeping Univ. (Sweden). Center for Medical Image Science and Visualization (CMIV); Nuclear Physics Institute AS CR, Prague (Czech Republic). Dept. of Radiation Dosimetry; Muhammad, Arif [Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Carlsson, Gudrun Alm [Linkoeping Univ. (Sweden). Dept. of Medical and Health Sciences, Radiation Physics; Linkoeping Univ. (Sweden). Center for Medical Image Science and Visualization (CMIV)

2011-07-01

Quantitative tissue classification using dual-energy CT has the potential to improve accuracy in radiation therapy dose planning as it provides more information about material composition of scanned objects than the currently used methods based on single-energy CT. One problem that hinders successful application of both single- and dual-energy CT is the presence of beam hardening and scatter artifacts in reconstructed data. Current pre- and post-correction methods used for image reconstruction often bias CT attenuation values and thus limit their applicability for quantitative tissue classification. Here we demonstrate simulation studies with a novel iterative algorithm that decomposes every soft tissue voxel into three base materials: water, protein, and adipose. The results demonstrate that beam hardening artifacts can effectively be removed and accurate estimation of mass fractions of each base material can be achieved. Our iterative algorithm starts with calculating parallel projections on two previously reconstructed DECT volumes reconstructed from fan-beam or helical projections with small conebeam angle. The parallel projections are then used in an iterative loop. Future developments include segmentation of soft and bone tissue and subsequent determination of bone composition. (orig.)

[Association of human epicardial adipose tissue volume and inflammatory mediators with atherosclerosis and vulnerable coronary atherosclerotic plaque].

Science.gov (United States)

Zhou, Liangliang; Gong, Jianbin; Li, Demin; Lu, Guangming; Chen, Dong; Wang, Jing

2015-02-01

To investigate the relation of epicardial adipose tissue volume (EATV) determined by dual-source CT (DSCT) cardiac angiography and EAT-derived inflammatory factors to coronary heart disease (CHD) and vulnerable plaque. A total of 260 patients underwent cardiac computed tomography to evaluate stenosis of coronary artery, and blood samples were obtained from each patient. CHD was confirmed in 180 patients by DSA and CHD was excluded in the remaining 80 patients (NCHD). Vascular remodeling index and plaque vulnerability parameters (fatty volume, fibrous volume and calcification volume and fiber volume) were measured in CHD patients and correlation with EATV was analyzed. Epicardial adipose tissue (EAT) and intrathoracic adipose tissue (TAT) were collected from 40 CHD patients undergoing CABG surgery, and, mRNA and protein expressions of leptin and MMP9 were detected by RT-PCR and Western blot analysis. (1) The EATV was significantly higher in the CHD group than in NCHD group ((121.2 ± 40.6) mm³ vs. (74.7 ± 18.1) mm³, P = 0.01). (2) Subgroup analysis of the CHD patients demonstrated that EATV was significantly higher in patients with positive remodeling than in patients without positive remodeling ((97.6 ± 42.0) cm³ vs. (75.5 ± 25.4) cm³, P = 0.01). Lipid plaque volume was positively correlated with EATV (r = 0.34, P = 0.002); however, fiber plaque volume was negatively correlated with EATV (r = -0.30, P = 0.008). (3) Logistic regression analysis indicated that EATV was an independent risk factor for positive vascular remodeling (OR = 2.01, 95% CI: 1.30-2.32, P = 0.01). (4) mRNA and protein expression of leptin and MMP9 in EAT was significantly upregulated in 40 CHD patients who received CABG surgery compared to 40 NCHD patients (P 0.05) in mRNA and protein expression of leptin and MMP9 from the SAT between CHD and NCHD patients. (5) In the CHD group, leptin and MMP9 levels in EAT and EATV were positively correlated with lipid plaque volume and fibrous plaque

Dual resolution cone beam breast CT: A feasibility study

International Nuclear Information System (INIS)

Chen Lingyun; Shen Youtao; Lai, Chao-Jen; Han Tao; Zhong Yuncheng; Ge Shuaiping; Liu Xinming; Wang Tianpeng; Yang, Wei T.; Whitman, Gary J.; Shaw, Chris C.

2009-01-01

Purpose: In this study, the authors investigated the feasibility of a dual resolution volume-of-interest (VOI) cone beam breast CT technique and compared two implementation approaches in terms of dose saving and scatter reduction. Methods: With this technique, a lead VOI mask with an opening is inserted between the x-ray source and the breast to deliver x-ray exposure to the VOI while blocking x rays outside the VOI. A CCD detector is used to collect the high resolution projection data of the VOI. Low resolution cone beam CT (CBCT) images of the entire breast, acquired with a flat panel (FP) detector, were used to calculate the projection data outside the VOI with the ray-tracing reprojection method. The Feldkamp-Davis-Kress filtered backprojection algorithm was used to reconstruct the dual resolution 3D images. Breast phantoms with 180 μm and smaller microcalcifications (MCs) were imaged with both FP and FP-CCD dual resolution CBCT systems, respectively. Two approaches of implementing the dual resolution technique, breast-centered approach and VOI-centered approach, were investigated and evaluated for dose saving and scatter reduction with Monte Carlo simulation using a GEANT4 package. Results: The results showed that the breast-centered approach saved more breast absorbed dose than did VOI-centered approach with similar scatter reduction. The MCs in fatty breast phantom, which were invisible with FP CBCT scan, became visible with the FP-CCD dual resolution CBCT scan. Conclusions: These results indicate potential improvement of the image quality inside the VOI with reduced breast dose both inside and outside the VOI.

Localization of Epileptogenic Zones using Partical Volume Corrected FDG Uptake on FDG PET and Voxel Based Morphometry on MRI

Energy Technology Data Exchange (ETDEWEB)

Kang, Won Jun; Lee, Ho Young; Lee, Jae Sung; Lee, Dong Soo; Lee, Sang Kun; Chung, June Key; Lee, Myung Chul [College of Medicine, Univ. of Seoul National, Seoul (Korea, Republic of)

2003-07-01

Partial volume corrected (PVC) FDG uptake yields information about regional metabolic level void of volume change, and voxel based morphometry (VBM) yields objective information regarding gray matter concentration. We investigated the roles of PVC PET and VBM to localize epileptogenic zones in medial temporal lobe epilepsy (mTLE) and non-lesional neocortical epilepsy. As a control group for PVC, 40 normal volunteers without history of neurologic or psychiatric diseases underwent FDG PET and MRI. Seventeen mTLE patients (M: F=7: 10, age=309 y) and nine neocortical epilepsy patients (M: F=6: 3, age=246, lateral temporal: 5, frontal: 3, occipital: 1) confirmed by surgery or epilepsy board meeting were enrolled. Standard VBM analysis was performed using individual MRI images compared with those of age-matched controls. For PVC, FDG PET was co-registered with its own MRI. PVC PET was obtained by dividing spillover-corrected PET by smoothed gray matter image pixel by pixel. SPAM was applied as a mask of volume of interest (VOI) to calculate gyral FDG uptake on PVC-FDG PET. Hippocampus, amygdala, superior, middle, inferior temporal gyrus and parahippocampal gyrus were the gyral SPAM VOIs in mTLE. Globally normalized PVC-FDG counts were compared with those of age-matched controls in mTLE and neocortical epilepsy patients. In mTlE, PVC-FDG PET correctly localized epileptogenic zones with the accuracy of 76% (13/17) in hippocampus and 82% (14/17) in any of six regions. VBM correctly localized 59% (10/17) in mTLE. In neocortical epilepsy, PVC-FDG PET localized epileptogenic zones in 44%, and VBM in 33%, Using VBM and PVC-FDG PET altogether, epileptogenic zones were localized in 66% (6/9). In mTLE, gyral PVC FDG uptake of temporal lobes was useful in localizing epileptogenic zones by demonstrating partial volume-void FDG concentration. In non-lesional cryptogenic neocortical epilepsy, combination of PVC-FDG PET and VBM is recommended to localize epileptogenic zones.

Clinical Evaluation of Zero-Echo-Time Attenuation Correction for Brain 18F-FDG PET/MRI: Comparison with Atlas Attenuation Correction.

Science.gov (United States)

Sekine, Tetsuro; Ter Voert, Edwin E G W; Warnock, Geoffrey; Buck, Alfred; Huellner, Martin; Veit-Haibach, Patrick; Delso, Gaspar

2016-12-01

Accurate attenuation correction (AC) on PET/MR is still challenging. The purpose of this study was to evaluate the clinical feasibility of AC based on fast zero-echo-time (ZTE) MRI by comparing it with the default atlas-based AC on a clinical PET/MR scanner. We recruited 10 patients with malignant diseases not located on the brain. In all patients, a clinically indicated whole-body 18 F-FDG PET/CT scan was acquired. In addition, a head PET/MR scan was obtained voluntarily. For each patient, 2 AC maps were generated from the MR images. One was atlas-AC, derived from T1-weighted liver acquisition with volume acceleration flex images (clinical standard). The other was ZTE-AC, derived from proton-density-weighted ZTE images by applying tissue segmentation and assigning continuous attenuation values to the bone. The AC map generated by PET/CT was used as a silver standard. On the basis of each AC map, PET images were reconstructed from identical raw data on the PET/MR scanner. All PET images were normalized to the SPM5 PET template. After that, these images were qualified visually and quantified in 67 volumes of interest (VOIs; automated anatomic labeling, atlas). Relative differences and absolute relative differences between PET images based on each AC were calculated. 18 F-FDG uptake in all 670 VOIs and generalized merged VOIs were compared using a paired t test. Qualitative analysis shows that ZTE-AC was robust to patient variability. Nevertheless, misclassification of air and bone in mastoid and nasal areas led to the overestimation of PET in the temporal lobe and cerebellum (%diff of ZTE-AC, 2.46% ± 1.19% and 3.31% ± 1.70%, respectively). The |%diff| of all 670 VOIs on ZTE was improved by approximately 25% compared with atlas-AC (ZTE-AC vs. atlas-AC, 1.77% ± 1.41% vs. 2.44% ± 1.63%, P PET in regions near the skull base. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

The Power of Neuroimaging Biomarkers for Screening Frontotemporal Dementia

Science.gov (United States)

McMillan, Corey T.; Avants, Brian B.; Cook, Philip; Ungar, Lyle; Trojanowski, John Q.; Grossman, Murray

2014-01-01

Frontotemporal dementia (FTD) is a clinically and pathologically heterogeneous neurodegenerative disease that can result from either frontotemporal lobar degeneration (FTLD) or Alzheimer’s disease (AD) pathology. It is critical to establish statistically powerful biomarkers that can achieve substantial cost-savings and increase feasibility of clinical trials. We assessed three broad categories of neuroimaging methods to screen underlying FTLD and AD pathology in a clinical FTD series: global measures (e.g., ventricular volume), anatomical volumes of interest (VOIs) (e.g., hippocampus) using a standard atlas, and data-driven VOIs using Eigenanatomy. We evaluated clinical FTD patients (N=93) with cerebrospinal fluid, gray matter (GM) MRI, and diffusion tensor imaging (DTI) to assess whether they had underlying FTLD or AD pathology. Linear regression was performed to identify the optimal VOIs for each method in a training dataset and then we evaluated classification sensitivity and specificity in an independent test cohort. Power was evaluated by calculating minimum sample sizes (mSS) required in the test classification analyses for each model. The data-driven VOI analysis using a multimodal combination of GM MRI and DTI achieved the greatest classification accuracy (89% SENSITIVE; 89% SPECIFIC) and required a lower minimum sample size (N=26) relative to anatomical VOI and global measures. We conclude that a data-driven VOI approach employing Eigenanatomy provides more accurate classification, benefits from increased statistical power in unseen datasets, and therefore provides a robust method for screening underlying pathology in FTD patients for entry into clinical trials. PMID:24687814

SU-E-J-114: A Practical Hybrid Method for Improving the Quality of CT-CBCT Deformable Image Registration for Head and Neck Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Liu, C; Kumarasiri, A; Chetvertkov, M; Gordon, J; Chetty, I; Siddiqui, F; Kim, J [Henry Ford Health System, Detroit, MI (United States)

2015-06-15

Purpose: Accurate deformable image registration (DIR) between CT and CBCT in H&N is challenging. In this study, we propose a practical hybrid method that uses not only the pixel intensities but also organ physical properties, structure volume of interest (VOI), and interactive local registrations. Methods: Five oropharyngeal cancer patients were selected retrospectively. For each patient, the planning CT was registered to the last fraction CBCT, where the anatomy difference was largest. A three step registration strategy was tested; Step1) DIR using pixel intensity only, Step2) DIR with additional use of structure VOI and rigidity penalty, and Step3) interactive local correction. For Step1, a public-domain open-source DIR algorithm was used (cubic B-spline, mutual information, steepest gradient optimization, and 4-level multi-resolution). For Step2, rigidity penalty was applied on bony anatomies and brain, and a structure VOI was used to handle the body truncation such as the shoulder cut-off on CBCT. Finally, in Step3, the registrations were reviewed on our in-house developed software and the erroneous areas were corrected via a local registration using level-set motion algorithm. Results: After Step1, there were considerable amount of registration errors in soft tissues and unrealistic stretching in the posterior to the neck and near the shoulder due to body truncation. The brain was also found deformed to a measurable extent near the superior border of CBCT. Such errors could be effectively removed by using a structure VOI and rigidity penalty. The rest of the local soft tissue error could be corrected using the interactive software tool. The estimated interactive correction time was approximately 5 minutes. Conclusion: The DIR using only the image pixel intensity was vulnerable to noise and body truncation. A corrective action was inevitable to achieve good quality of registrations. We found the proposed three-step hybrid method efficient and practical for CT

Synthesized interstitial lung texture for use in anthropomorphic computational phantoms

Science.gov (United States)

Becchetti, Marc F.; Solomon, Justin B.; Segars, W. Paul; Samei, Ehsan

2016-04-01

A realistic model of the anatomical texture from the pulmonary interstitium was developed with the goal of extending the capability of anthropomorphic computational phantoms (e.g., XCAT, Duke University), allowing for more accurate image quality assessment. Contrast-enhanced, high dose, thorax images for a healthy patient from a clinical CT system (Discovery CT750HD, GE healthcare) with thin (0.625 mm) slices and filtered back- projection (FBP) were used to inform the model. The interstitium which gives rise to the texture was defined using 24 volumes of interest (VOIs). These VOIs were selected manually to avoid vasculature, bronchi, and bronchioles. A small scale Hessian-based line filter was applied to minimize the amount of partial-volumed supernumerary vessels and bronchioles within the VOIs. The texture in the VOIs was characterized using 8 Haralick and 13 gray-level run length features. A clustered lumpy background (CLB) model with added noise and blurring to match CT system was optimized to resemble the texture in the VOIs using a genetic algorithm with the Mahalanobis distance as a similarity metric between the texture features. The most similar CLB model was then used to generate the interstitial texture to fill the lung. The optimization improved the similarity by 45%. This will substantially enhance the capabilities of anthropomorphic computational phantoms, allowing for more realistic CT simulations.

Analysis of end-systolic pressure-volume relation by gated radionuclide angiocardiography

International Nuclear Information System (INIS)

Adachi, Haruhiko; Sugihara, Horoki; Katsume, Hiroshi; Ijichi, Hamao; Miyanaga, Hajime

1982-01-01

Left ventricular end-systolic pressure-volume relation has been proved experimentally to b e an useful index of left ventricular contractility relatively independent of preload or afterload. But less clinical application has been reported because of its invasive nature, and we evaluated this relationship non-invasively using gated radionuclide angiocardiography as volume determination and cuff sphyngomanometer in the arm as pressure measurement. Gated equilibrium blood pool scintigrams were obtained at rest and during intravenous infusion of angiotensin or nitrate. Ventricular volumes were derived from ventricular activity and peripheral blood volume and activity. The peak systolic pressure (PSP) by cuff method to end-systolic volume index (ESVI) relations showed good linearity (r gt .930 in 84% of consecutive 50 cases) and were gentler in the groups with more impaired left ventricular function. Emax was related exponentially to ejection fraction (EF) and hyperbolically to end-diastolic volume index. The dead volume (VoI) was unfixed and fell into positive or negative value, and was not related to EF under control condition. PSP/ESVI in each loading condition was less variable with the alteration of blood pressure than EF. The linear relation was found between PSP/ESVI under control condition and Emax (PSP/ESVI = 0.651.Emax + 0.958, r = 0.841, p lt .001). Thus in measuring ventricular volume, gated radionuclide angiocardiography is a non-invasive method less affected by the geometry of the left ventricle. Non-invasive determination of end-systolic pressure-volume relation using the volume by radionuclide and the blood pressure by cuff method is clinically useful in the assessment of left ventricular contractility. (author)

Estimation of lung volume and pulmonary blood volume from radioisotopic images

International Nuclear Information System (INIS)

Kanazawa, Minoru

1989-01-01

Lung volume and pulmonary blood volume in man were estimated from the radioisotopic image using single photon emission computed tomography (SPECT). Six healthy volunteers were studied in a supine position with normal and altered lung volumes by applying continuous negative body-surface pressure (CNP) and by positive end-expiratory pressure (PEEP). 99m Tc labeled human serum albumin was administered as an aerosol to image the lungs. The CNP caused the diaphragm to be lowered and it increased the mean lung tissue volume obtained by SPECT from 3.09±0.49 l for baseline to 3.67±0.62 l for 10 cmH 2 O (p 2 O (p 2 O), respectively. The PEEP also increased the lung tissue volume to 3.68±0.68 l for 10 cmH 2 O as compared with the baseline (p 2 O PEEP. The lung tissue volume obtained by SPECT showed a positive correlation with functional residual capacity measured by the He dilution method (r=0.91, p 99m Tc-labeled red blood cells. The L/H ratio decreased after either the CNP or PEEP, suggesting a decrease in the blood volume per unit lung volume. However, it was suggested that the total pulmonary blood volume increased slightly either on the CNP (+7.4% for 10 cmH 2 O, p 2 O,p<0.05) when we extrapolated the L/H ratio to the whole lungs by multiplying the lung tissue volume obtained by SPECT. We concluded that SPECT could offer access to the estimation of lung volume and pulmonary blood volume in vivo. (author)

Whole-body adipose tissue and lean muscle volumes and their distribution across gender and age: MR-derived normative values in a normal-weight Swiss population.

Science.gov (United States)

Ulbrich, Erika J; Nanz, Daniel; Leinhard, Olof Dahlqvist; Marcon, Magda; Fischer, Michael A

2018-01-01

To determine age- and gender-dependent whole-body adipose tissue and muscle volumes in healthy Swiss volunteers in Dixon MRI in comparison with anthropometric and bioelectrical impedance (BIA) measurements. Fat-water-separated whole-body 3 Tesla MRI of 80 healthy volunteers (ages 20 to 62 years) with a body mass index (BMI) of 17.5 to 26.2 kg/m 2 (10 men, 10 women per decade). Age and gender-dependent volumes of total adipose tissue (TAT), visceral adipose tissue (VAT), total abdominal subcutaneous adipose tissue (ASAT) and total abdominal adipose tissue (TAAT), and the total lean muscle tissue (TLMT) normalized for body height were determined by semi-automatic segmentation, and correlated with anthropometric and BIA measurements as well as lifestyle parameters. The TAT, ASAT, VAT, and TLMT indexes (TATi, ASATi, VATi, and TLMTi, respectively) (L/m 2  ± standard deviation) for women/men were 6.4 ± 1.8/5.3 ± 1.7, 1.6 ± 0.7/1.2 ± 0.5, 0.4 ± 0.2/0.8 ± 0.5, and 5.6 ± 0.6/7.1 ± 0.7, respectively. The TATi correlated strongly with ASATi (r > 0.93), VATi, BMI and BIA (r > 0.70), and TAATi (r > 0.96), and weak with TLMTi for both genders (r > -0.34). The VAT was the only parameter showing an age dependency (r > 0.32). The BMI and BIA showed strong correlation with all MR-derived adipose tissue volumes. The TAT mass was estimated significantly lower from BIA than from MRI (both genders P muscle volumes might serve as normative values. The estimation of adipose tissue volumes was significantly lower from anthropometric and BIA measurements than from MRI. Magn Reson Med 79:449-458, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Marrow Adipose Tissue in Older Men: Association with Visceral and Subcutaneous Fat, Bone Volume, Metabolism, and Inflammation.

Science.gov (United States)

Bani Hassan, Ebrahim; Demontiero, Oddom; Vogrin, Sara; Ng, Alvin; Duque, Gustavo

2018-03-26

Marrow (MAT) and subcutaneous (SAT) adipose tissues display different metabolic profiles and varying associations with aging, bone density, and fracture risk. Using a non-invasive imaging methodology, we aimed to investigate the associations between MAT, SAT, and visceral fat (VAT) with bone volume, bone remodeling markers, insulin resistance, and circulating inflammatory mediators in a population of older men. In this cross-sectional study, 96 healthy men (mean age 67 ± 5.5) were assessed for anthropometric parameters, body composition, serum biochemistry, and inflammatory panel. Using single-energy computed tomography images, MAT (in L2 and L3 and both hips), VAT, and SAT (at the level of L2-L3 and L4-L5) were measured employing Slice-O-Matic software (Tomovision), which enables specific tissue demarcation applying previously reported Hounsfield unit thresholds. MAT volume was similar in all anatomical sites and independent of BMI. In all femoral regions of interest (ROIs) there was a strong negative association between bone and MAT volumes (r = - 0.840 to - 0.972, p strong inverse correlations between MAT and bone mass, which have been previously observed in women, were also confirmed in older men. However, MAT volume in all ROIs was interrelated and unlike women, mainly independent of VAT or SAT. The lack of strong association between MAT vs VAT/SAT, and its discordant associations with metabolic and inflammatory mediators provide further evidence on MAT's distinct attributes in older men.

A higher volume of fibrotic tissue on virtual histology prior to coronary stent implantation predisposes to more pronounced neointima proliferation.

Science.gov (United States)

Haine, Steven; Wouters, Kristien; Miljoen, Hielko; Vandendriessche, Tom; Claeys, Marc; Bosmans, Johan; Vrints, Christiaan

2018-04-01

Since neointima smooth muscle cells (SMC) mainly originate from the vessel wall, we investigated whether atherosclerotic plaque composition influences subsequent in-stent neointima proliferation and restenosis. We performed intravascular ultrasound (IVUS) with virtual histology in 98 patients prior to elective bare-metal stent (BMS) implantation in de novo coronary artery lesions. Virtual histology variables pre-percutaneous coronary intervention (PCI) were related to in-stent neointima proliferation six months after implantation assessed as late luminal loss of 0.88 mm (interquartile range (IQR) 0.37-1.23 mm) on angiography and as maximal percentage area stenosis of 42% (IQR 33-59%) and percentage volume intima hyperplasia of 27% (IQR 20-36%) on IVUS. A ridge-trace based multiple linear regression model was constructed to account for multicollinearity of the virtual histology variables and was corrected for implanted stent length (18 mm, IQR 15-23 mm), stent diameter (3.0 mm, IQR 2.75-3.5 mm) and lesion volume (146 mm³, IQR 80-201 mm³) prior to PCI. Fibrous tissue volume prior to PCI (49 mm³, IQR 30-77 mm³) was significantly and independently related to late luminal loss (p = .038), maximal percentage area stenosis (p = .041) and percentage volume intima hyperplasia (p = .004). Neither absolute nor relative amounts of fibrofatty, calcified or necrotic core tissue appeared related to any of the restenosis parameters. Subgroup analysis after exclusion of acute coronary syndrome (ACS) patients yielded similar results. Lesions with more voluminous fibrotic tissue pre-PCI show more pronounced in-stent neointima proliferation, even after correction for lesion plaque volume.

A stereotaxic, population-averaged T1w ovine brain atlas including cerebral morphology and tissue volumes

Directory of Open Access Journals (Sweden)

Björn eNitzsche

2015-06-01

Full Text Available Standard stereotaxic reference systems play a key role in human brain studies. Stereotaxic coordinate systems have also been developed for experimental animals including non-human primates, dogs and rodents. However, they are lacking for other species being relevant in experimental neuroscience including sheep. Here, we present a spatial, unbiased ovine brain template with tissue probability maps (TPM that offer a detailed stereotaxic reference frame for anatomical features and localization of brain areas, thereby enabling inter-individual and cross-study comparability. Three-dimensional data sets from healthy adult Merino sheep (Ovis orientalis aries, 12 ewes and 26 neutered rams were acquired on a 1.5T Philips MRI using a T1w sequence. Data were averaged by linear and non-linear registration algorithms. Moreover, animals were subjected to detailed brain volume analysis including examinations with respect to body weight, age and sex. The created T1w brain template provides an appropriate population-averaged ovine brain anatomy in a spatial standard coordinate system. Additionally, TPM for gray (GM and white (WM matter as well as cerebrospinal fluid (CSF classification enabled automatic prior-based tissue segmentation using statistical parametric mapping (SPM. Overall, a positive correlation of GM volume and body weight explained about 15% of the variance of GM while a positive correlation between WM and age was found. Absolute tissue volume differences were not detected, indeed ewes showed significantly more GM per bodyweight as compared to neutered rams. The created framework including spatial brain template and TPM represent a useful tool for unbiased automatic image preprocessing and morphological characterization in sheep. Therefore, the reported results may serve as a starting point for further experimental and/or translational research aiming at in vivo analysis in this species.

Predicting volume of distribution with decision tree-based regression methods using predicted tissue:plasma partition coefficients.

Science.gov (United States)

Freitas, Alex A; Limbu, Kriti; Ghafourian, Taravat

2015-01-01

Volume of distribution is an important pharmacokinetic property that indicates the extent of a drug's distribution in the body tissues. This paper addresses the problem of how to estimate the apparent volume of distribution at steady state (Vss) of chemical compounds in the human body using decision tree-based regression methods from the area of data mining (or machine learning). Hence, the pros and cons of several different types of decision tree-based regression methods have been discussed. The regression methods predict Vss using, as predictive features, both the compounds' molecular descriptors and the compounds' tissue:plasma partition coefficients (Kt:p) - often used in physiologically-based pharmacokinetics. Therefore, this work has assessed whether the data mining-based prediction of Vss can be made more accurate by using as input not only the compounds' molecular descriptors but also (a subset of) their predicted Kt:p values. Comparison of the models that used only molecular descriptors, in particular, the Bagging decision tree (mean fold error of 2.33), with those employing predicted Kt:p values in addition to the molecular descriptors, such as the Bagging decision tree using adipose Kt:p (mean fold error of 2.29), indicated that the use of predicted Kt:p values as descriptors may be beneficial for accurate prediction of Vss using decision trees if prior feature selection is applied. Decision tree based models presented in this work have an accuracy that is reasonable and similar to the accuracy of reported Vss inter-species extrapolations in the literature. The estimation of Vss for new compounds in drug discovery will benefit from methods that are able to integrate large and varied sources of data and flexible non-linear data mining methods such as decision trees, which can produce interpretable models. Graphical AbstractDecision trees for the prediction of tissue partition coefficient and volume of distribution of drugs.

Renal cortical and medullary blood flow responses to altered NO-availability in humans

DEFF Research Database (Denmark)

Damkjaer, Mads; Vafaee, Manoucher; Møller, Michael Lehd

2010-01-01

The objective was to quantify regional renal blood flow in humans. In nine young volunteers on a controlled diet, the lower abdomen was CT-scanned and regional renal blood flow determined by positron emission tomography (PET) scanning using H(2)(15)O as tracer. Measurements were performed...... of one voxel were eliminated stepwise from the external surface of the VOI ('voxel peeling'), and the blood flow subsequently determined in each new, reduced VOI. Blood flow in the shrinking volumes of interest (VOIs) decreased as the number of cycles of voxel peeling increased. After 4-5 cycles, blood...... flow was not reduced further by additional voxel peeling. This volume-insensitive flow was measured to be 2.30 ±0.17 ml·(g·min)(-1) during the control period; it increased during infusion of glyceryl nitrate to 2.97 ±0.18 ml·(g·min)(-1) (p...

Non-invasive assessment of distribution volume ratios and binding potential: tissue heterogeneity and interindividually averaged time-activity curves

Energy Technology Data Exchange (ETDEWEB)

Reimold, M.; Mueller-Schauenburg, W.; Dohmen, B.M.; Bares, R. [Department of Nuclear Medicine, University of Tuebingen, Otfried-Mueller-Strasse 14, 72076, Tuebingen (Germany); Becker, G.A. [Nuclear Medicine, University of Leipzig, Leipzig (Germany); Reischl, G. [Radiopharmacy, University of Tuebingen, Tuebingen (Germany)

2004-04-01

Due to the stochastic nature of radioactive decay, any measurement of radioactivity concentration requires spatial averaging. In pharmacokinetic analysis of time-activity curves (TAC), such averaging over heterogeneous tissues may introduce a systematic error (heterogeneity error) but may also improve the accuracy and precision of parameter estimation. In addition to spatial averaging (inevitable due to limited scanner resolution and intended in ROI analysis), interindividual averaging may theoretically be beneficial, too. The aim of this study was to investigate the effect of such averaging on the binding potential (BP) calculated with Logan's non-invasive graphical analysis and the ''simplified reference tissue method'' (SRTM) proposed by Lammertsma and Hume, on the basis of simulated and measured positron emission tomography data [{sup 11}C]d-threo-methylphenidate (dMP) and [{sup 11}C]raclopride (RAC) PET. dMP was not quantified with SRTM since the low k {sub 2} (washout rate constant from the first tissue compartment) introduced a high noise sensitivity. Even for considerably different shapes of TAC (dMP PET in parkinsonian patients and healthy controls, [{sup 11}C]raclopride in patients with and without haloperidol medication) and a high variance in the rate constants (e.g. simulated standard deviation of K {sub 1}=25%), the BP obtained from average TAC was close to the mean BP (<5%). However, unfavourably distributed parameters, especially a correlated large variance in two or more parameters, may lead to larger errors. In Monte Carlo simulations, interindividual averaging before quantification reduced the variance from the SRTM (beyond a critical signal to noise ratio) and the bias in Logan's method. Interindividual averaging may further increase accuracy when there is an error term in the reference tissue assumption E=DV {sub 2}-DV ' (DV {sub 2} = distribution volume of the first tissue compartment, DV &apos

TU-H-CAMPUS-JeP2-01: Inter-Observer Delineation Comparison of Visible Glandular Breast Tissue On Magnetic Resonance Imaging and Computed Tomography (prone and Supine)

International Nuclear Information System (INIS)

Pogson, EM; Delaney, G; Yap, M; Ahern, V; Boxer, M; David, S; Dimigen, M; Harvey, J; Koh, E; Batumalai, V; Lim, K; Papadatos, G; Metcalfe, P

2016-01-01

Purpose: Breast cancers predominantly arise from Glandular Breast Tissue (GBT). If the GBT can be treated effectively post-operatively utilising radiotherapy this may be adequate volumetric coverage for adjuvant breast radiotherapy. Adequate imaging of the GBT is necessary and will be assessed between MRI and CT modalities. GBT visualisation is acknowledged to be qualitatively superior on Magnetic Resonance Image (MRI) compared to Computed Tomography (CT), the current radiotherapy imaging standard, however this has not been quantitatively assessed. For radiotherapy purposes it is important that any treatment volume can be consistently defined between observers. This study investigates the consistency of CT and MRI GBT contours for potential radiotherapy planning. Methods: Ten experts (9 breast radiation oncologists and 1 radiologist) contoured the extent of the visible GBT for 33 patients on MRI and CT (both without contrast), which was performed according to a contouring guideline in supine and prone patient positions. The GBT volume was not a conventional whole breast radiotherapy planning volume, but rather the extent of GBT that was indicated from the CT or MR imaging. Volumes were compared utilizing the dice similarity coefficient (DSC), kappa statistic, and Hausdorff Distances (HDs) to ascertain the modality that was most consistently volumed. Results: The inter-observer concordance was of substantial agreement (kappa above 0.6) for the CT supine, CT prone, MRI supine and MRI prone datasets. The MRI GBT volumes were larger than the CT GBT volumes (p<0.001). Inter-observer conformity was higher for CT than MRI, although the magnitude of this difference was small (VOI<0.04). Conformity between modalities (CT and MRI) was in agreement for both prone and supine, DSC=0.75. Prone GBT volumes were larger than supine for both MRI and CT. Conclusion: MRI improves the extent of GBT delineation. The role of MRI guided, GBT-targeted radiotherapy requires investigation in

TU-H-CAMPUS-JeP2-01: Inter-Observer Delineation Comparison of Visible Glandular Breast Tissue On Magnetic Resonance Imaging and Computed Tomography (prone and Supine)

Energy Technology Data Exchange (ETDEWEB)

Pogson, EM [Institute of Medical Physics, University of Sydney, Sydney, NSW (Australia); University of Wollongong, Wollongong, NSW (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW (Australia); Delaney, G; Yap, M [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney, NSW (Australia); School of Medicine, University of Western Sydney, Sydney, NSW (Australia); Ahern, V [Westmead Hospital, Westmead, NSW (Australia); Boxer, M [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW (Australia); David, S [Peter MacCallum Cancer Institute,, Melbourne, VIC (Australia); Dimigen, M [Department of Radiology, Liverpool Hospital, NSW (United Kingdom); Harvey, J [University of Queensland, Brisbane, QLD (Australia); Princess Alexandra Hospital, QLD (Australia); Koh, E; Batumalai, V [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW (Australia); South Western Sydney Clinical School, University of New South Wales, Sydney, NSW (Australia); Lim, K; Papadatos, G [Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Metcalfe, P [University of Wollongong, Wollongong, NSW (Australia); Liverpool and Macarthur Cancer Therapy Centres, Liverpool, NSW (United Kingdom); Ingham Institute for Applied Medical Research, Liverpool Hospital, Sydney, NSW (Australia); and others

2016-06-15

Purpose: Breast cancers predominantly arise from Glandular Breast Tissue (GBT). If the GBT can be treated effectively post-operatively utilising radiotherapy this may be adequate volumetric coverage for adjuvant breast radiotherapy. Adequate imaging of the GBT is necessary and will be assessed between MRI and CT modalities. GBT visualisation is acknowledged to be qualitatively superior on Magnetic Resonance Image (MRI) compared to Computed Tomography (CT), the current radiotherapy imaging standard, however this has not been quantitatively assessed. For radiotherapy purposes it is important that any treatment volume can be consistently defined between observers. This study investigates the consistency of CT and MRI GBT contours for potential radiotherapy planning. Methods: Ten experts (9 breast radiation oncologists and 1 radiologist) contoured the extent of the visible GBT for 33 patients on MRI and CT (both without contrast), which was performed according to a contouring guideline in supine and prone patient positions. The GBT volume was not a conventional whole breast radiotherapy planning volume, but rather the extent of GBT that was indicated from the CT or MR imaging. Volumes were compared utilizing the dice similarity coefficient (DSC), kappa statistic, and Hausdorff Distances (HDs) to ascertain the modality that was most consistently volumed. Results: The inter-observer concordance was of substantial agreement (kappa above 0.6) for the CT supine, CT prone, MRI supine and MRI prone datasets. The MRI GBT volumes were larger than the CT GBT volumes (p<0.001). Inter-observer conformity was higher for CT than MRI, although the magnitude of this difference was small (VOI<0.04). Conformity between modalities (CT and MRI) was in agreement for both prone and supine, DSC=0.75. Prone GBT volumes were larger than supine for both MRI and CT. Conclusion: MRI improves the extent of GBT delineation. The role of MRI guided, GBT-targeted radiotherapy requires investigation in

Receiver operating characteristic (ROC) curve for classification of {sup 18}F-NaF uptake on PET/CT

Energy Technology Data Exchange (ETDEWEB)

Valadares, Agnes Araujo, E-mail: agnesvaladares@me.com [Universidade de Sao Paulo (HC/FM/USP), SP (Brazil). Hospital das Clinicas. Fac. de Mediciana; Duarte, Paulo Schiavom; Ono, Carla Rachel; Coura-Filho, George Barberio; Sado, Heitor Naoki; Carvalho, Giovanna [Instituto do Cancer do Estado de Sao Paulo Octavio Frias de Oliveira (ICESP), Sao Paulo, SP (Brazil). Servico de Medicina Nuclear; Sapienza, Marcelo Tatit; Buchpiguel, Carlos Alberto [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Fac. de Medicina. Dept. de Radiologia e Oncologia

2016-01-15

Objective: To assess the cutoff values established by ROC curves to classify {sup 18}F-NaF uptake as normal or malignant. Materials and Methods: PET/CT images were acquired 1 hour after administration of 185 MBq of {sup 18}F-NaF. Volumes of interest (VOIs) were drawn on three regions of the skeleton as follows: proximal right humerus diaphysis (HD), proximal right femoral diaphysis (FD) and first vertebral body (VB1), in a total of 254 patients, totalling 762 VOIs. The uptake in the VOIs was classified as normal or malignant on the basis of the radiopharmaceutical distribution pattern and of the CT images. A total of 675 volumes were classified as normal and 52 were classified as malignant. Thirty-five VOIs classified as indeterminate or nonmalignant lesions were excluded from analysis. The standardized uptake value (SUV) measured on the VOIs were plotted on an ROC curve for each one of the three regions. The area under the ROC (AUC) as well as the best cutoff SUVs to classify the VOIs were calculated. The best cutoff values were established as the ones with higher result of the sum of sensitivity and specificity. Results: The AUCs were 0.933, 0.889 and 0.975 for UD, FD and VB1, respectively. The best SUV cutoffs were 9.0 (sensitivity: 73%; specificity: 99%), 8.4 (sensitivity: 79%; specificity: 94%) and 21.0 (sensitivity: 93%; specificity: 95%) for UD, FD and VB1, respectively. Conclusion: The best cutoff value varies according to bone region of analysis and it is not possible to establish one value for the whole body. (author)

Evaluation of software tools for automated identification of neuroanatomical structures in quantitative β-amyloid PET imaging to diagnose Alzheimer's disease

Energy Technology Data Exchange (ETDEWEB)

Tuszynski, Tobias; Luthardt, Julia; Butzke, Daniel; Tiepolt, Solveig; Seese, Anita; Barthel, Henryk [Leipzig University Medical Centre, Department of Nuclear Medicine, Leipzig (Germany); Rullmann, Michael; Hesse, Swen; Sabri, Osama [Leipzig University Medical Centre, Department of Nuclear Medicine, Leipzig (Germany); Leipzig University Medical Centre, Integrated Treatment and Research Centre (IFB) Adiposity Diseases, Leipzig (Germany); Gertz, Hermann-Josef [Leipzig University Medical Centre, Department of Psychiatry, Leipzig (Germany); Lobsien, Donald [Leipzig University Medical Centre, Department of Neuroradiology, Leipzig (Germany)

2016-06-15

For regional quantification of nuclear brain imaging data, defining volumes of interest (VOIs) by hand is still the gold standard. As this procedure is time-consuming and operator-dependent, a variety of software tools for automated identification of neuroanatomical structures were developed. As the quality and performance of those tools are poorly investigated so far in analyzing amyloid PET data, we compared in this project four algorithms for automated VOI definition (HERMES Brass, two PMOD approaches, and FreeSurfer) against the conventional method. We systematically analyzed florbetaben brain PET and MRI data of ten patients with probable Alzheimer's dementia (AD) and ten age-matched healthy controls (HCs) collected in a previous clinical study. VOIs were manually defined on the data as well as through the four automated workflows. Standardized uptake value ratios (SUVRs) with the cerebellar cortex as a reference region were obtained for each VOI. SUVR comparisons between ADs and HCs were carried out using Mann-Whitney-U tests, and effect sizes (Cohen's d) were calculated. SUVRs of automatically generated VOIs were correlated with SUVRs of conventionally derived VOIs (Pearson's tests). The composite neocortex SUVRs obtained by manually defined VOIs were significantly higher for ADs vs. HCs (p=0.010, d=1.53). This was also the case for the four tested automated approaches which achieved effect sizes of d=1.38 to d=1.62. SUVRs of automatically generated VOIs correlated significantly with those of the hand-drawn VOIs in a number of brain regions, with regional differences in the degree of these correlations. Best overall correlation was observed in the lateral temporal VOI for all tested software tools (r=0.82 to r=0.95, p<0.001). Automated VOI definition by the software tools tested has a great potential to substitute for the current standard procedure to manually define VOIs in β-amyloid PET data analysis. (orig.)

Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine

Directory of Open Access Journals (Sweden)

Drobek Christoph

2015-09-01

Full Text Available Particle Image Velocimetry (PIV measurements of a water-jet for water-assisted liposuction (WAL are carried out to investigate the distribution of velocity and therefore momentum and acting force on the human sub-cutaneous fat tissue. These results shall validate CFD simulations and force sensor measurements of the water-jet and support the development of a new WAL device that is able to harvest low volumes of fat tissue for regenerative medicine even gentler than regular WAL devices.

Evaluation of elastix-based propagated align algorithm for VOI- and voxel-based analysis of longitudinal (18)F-FDG PET/CT data from patients with non-small cell lung cancer (NSCLC).

Science.gov (United States)

Kerner, Gerald Sma; Fischer, Alexander; Koole, Michel Jb; Pruim, Jan; Groen, Harry Jm

2015-01-01

Deformable image registration allows volume of interest (VOI)- and voxel-based analysis of longitudinal changes in fluorodeoxyglucose (FDG) tumor uptake in patients with non-small cell lung cancer (NSCLC). This study evaluates the performance of the elastix toolbox deformable image registration algorithm for VOI and voxel-wise assessment of longitudinal variations in FDG tumor uptake in NSCLC patients. Evaluation of the elastix toolbox was performed using (18)F-FDG PET/CT at baseline and after 2 cycles of therapy (follow-up) data in advanced NSCLC patients. The elastix toolbox, an integrated part of the IMALYTICS workstation, was used to apply a CT-based non-linear image registration of follow-up PET/CT data using the baseline PET/CT data as reference. Lesion statistics were compared to assess the impact on therapy response assessment. Next, CT-based deformable image registration was performed anew on the deformed follow-up PET/CT data using the original follow-up PET/CT data as reference, yielding a realigned follow-up PET dataset. Performance was evaluated by determining the correlation coefficient between original and realigned follow-up PET datasets. The intra- and extra-thoracic tumors were automatically delineated on the original PET using a 41% of maximum standardized uptake value (SUVmax) adaptive threshold. Equivalence between reference and realigned images was tested (determining 95% range of the difference) and estimating the percentage of voxel values that fell within that range. Thirty-nine patients with 191 tumor lesions were included. In 37/39 and 12/39 patients, respectively, thoracic and non-thoracic lesions were evaluable for response assessment. Using the EORTC/SUVmax-based criteria, 5/37 patients had a discordant response of thoracic, and 2/12 a discordant response of non-thoracic lesions between the reference and the realigned image. FDG uptake values of corresponding tumor voxels in the original and realigned reference PET correlated well (R

Target volume delineation for head and neck cancer intensity-modulated radiotherapy; Delineation des volumes cibles des cancers des voies aerodigestives superieures en radiotherapie conformationnelle avec modulation d'intensite

Energy Technology Data Exchange (ETDEWEB)

Lapeyre, M.; Toledano, I.; Bourry, N. [Departement de radiotherapie, centre Jean-Perrin, 58, rue Montalembert, BP 5026, 63011 Clermont-Ferrand cedex 1 (France); Bailly, C. [Unite de radiodiagnostic, centre Jean-Perrin, 58, rue Montalembert, BP 5026, 63011 Clermont-Ferrand cedex 1 (France); Cachin, F. [Unite de medecine nucleaire, centre Jean-Perrin, 58, rue Montalembert, BP 5026, 63011 Clermont-Ferrand cedex 1 (France)

2011-10-15

This article describes the determination and the delineation of the target volumes for head-and-neck cancers treated with intensity-modulated radiotherapy (IMRT). The delineation of the clinical target volumes (CTV) on the computerized tomography scanner (CT scan) requires a rigorous methodology due to the complexity of head-and-neck anatomy. The clinical examination with a sketch of pretreatment tumour extension, the surgical and pathological reports and the adequate images (CT scan, magnetic resonance imaging and fluorodeoxyglucose positron emission tomography) are necessary for the delineation. The target volumes depend on the overall strategy: sequential IMRT or simultaneous integrated boost-IMRT (SIB-IMRT). The concept of selectivity of the potential subclinical disease near the primary tumor and the selection of neck nodal targets are described according to the recommendations and the literature. The planing target volume (PTV), mainly reflecting setup errors (random and systematic), results from a uniform 4-5 mm expansion around the CTV. We propose the successive delineation of: (1) the gross volume tumour (GTV); (2) the 'high risk' CTV1 around the GTV or including the postoperative tumour bed in case of positive margins or nodal extra-capsular spread (65-70 Gy in 30-35 fractions); (3) the CTV2 'intermediate risk' around the CTV1 for SIB-IMRT (59-63 Gy in 30-35 fractions); (4) the 'low-risk' CTV3 (54-56 Gy in 30-35 fractions); (5) the PTVs. (authors)

Laser-induced fluorescence imaging of subsurface tissue structures with a volume holographic spatial-spectral imaging system.

Science.gov (United States)

Luo, Yuan; Gelsinger-Austin, Paul J; Watson, Jonathan M; Barbastathis, George; Barton, Jennifer K; Kostuk, Raymond K

2008-09-15

A three-dimensional imaging system incorporating multiplexed holographic gratings to visualize fluorescence tissue structures is presented. Holographic gratings formed in volume recording materials such as a phenanthrenquinone poly(methyl methacrylate) photopolymer have narrowband angular and spectral transmittance filtering properties that enable obtaining spatial-spectral information within an object. We demonstrate this imaging system's ability to obtain multiple depth-resolved fluorescence images simultaneously.

VoiLA: A multidisciplinary study of Volatile recycling in the Lesser Antilles Arc

Science.gov (United States)

Collier, J.; Blundy, J. D.; Goes, S. D. B.; Henstock, T.; Harmon, N.; Kendall, J. M.; Macpherson, C.; Rietbrock, A.; Rychert, C.; Van Hunen, J.; Wilkinson, J.; Wilson, M.

2017-12-01

Project VoiLA will address the role of volatiles in controlling geological processes at subduction zones. The study area was chosen as it subducts oceanic lithosphere formed at the slow-spreading Mid Atlantic Ridge. This should result in a different level and pattern of hydration to compare with subduction zones in the Pacific which consume oceanic lithosphere generated at faster spreading rates. In five project components, we will test (1) where volatiles are held within the incoming plate; (2) where they are transported and released below the arc; (3) how the volatile distribution and pathways relate to the construction of the arc; and (4) their relationship to seismic and volcanic hazards and the fractionation of economic metals. Finally, (5) the behaviour of the Lesser Antilles arc will be compared with that of other well-studied systems to improve our wider understanding of the role of water in subduction processes. To address these questions the project will combine seismology; petrology and numerical modelling of wedge dynamics and its consequences on dehydration and melting. So-far island-based fieldwork has included mantle xenolith collection and installation of a temporary seismometer network. In 2016 and 2017 we conducted cruises onboard the RRS James Cook that collected a network of passive-recording and active-recording ocean-bottom seismometer data within the back-arc, fore-arc and incoming plate region. A total of 175 deployments and recoveries were made with the loss of only 6 stations. The presentation will present preliminary results from the project.

Applications of Micro-CT scanning in medicine and dentistry: Microstructural analyses of a Wistar Rat mandible and a urinary tract stone

Science.gov (United States)

Latief, F. D. E.; Sari, D. S.; Fitri, L. A.

2017-08-01

High-resolution tomographic imaging by means of x-ray micro-computed tomography (μCT) has been widely utilized for morphological evaluations in dentistry and medicine. The use of μCT follows a standard procedure: image acquisition, reconstruction, processing, evaluation using image analysis, and reporting of results. This paper discusses methods of μCT using a specific scanning device, the Bruker SkyScan 1173 High Energy Micro-CT. We present a description of the general workflow, information on terminology for the measured parameters and corresponding units, and further analyses that can potentially be conducted with this technology. Brief qualitative and quantitative analyses, including basic image processing (VOI selection and thresholding) and measurement of several morphometrical variables (total VOI volume, object volume, percentage of total volume, total VOI surface, object surface, object surface/volume ratio, object surface density, structure thickness, structure separation, total porosity) were conducted on two samples, the mandible of a wistar rat and a urinary tract stone, to illustrate the abilities of this device and its accompanying software package. The results of these analyses for both samples are reported, along with a discussion of the types of analyses that are possible using digital images obtained with a μCT scanning device, paying particular attention to non-diagnostic ex vivo research applications.

Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

International Nuclear Information System (INIS)

Herschtal, Alan; Te Marvelde, Luc; Mengersen, Kerrie; Foroudi, Farshad; Eade, Thomas; Pham, Daniel; Caine, Hannah; Kron, Tomas

2015-01-01

Objective: To develop a mathematical tool that can update a patient's planning target volume (PTV) partway through a course of radiation therapy to more precisely target the tumor for the remainder of treatment and reduce dose to surrounding healthy tissue. Methods and Materials: Daily on-board imaging was used to collect large datasets of displacements for patients undergoing external beam radiation therapy for solid tumors. Bayesian statistical modeling of these geometric uncertainties was used to optimally trade off between displacement data collected from previously treated patients and the progressively accumulating data from a patient currently partway through treatment, to optimally predict future displacements for that patient. These predictions were used to update the PTV position and margin width for the remainder of treatment, such that the clinical target volume (CTV) was more precisely targeted. Results: Software simulation of dose to CTV and normal tissue for 2 real prostate displacement datasets consisting of 146 and 290 patients treated with a minimum of 30 fractions each showed that re-evaluating the PTV position and margin width after 8 treatment fractions reduced healthy tissue dose by 19% and 17%, respectively, while maintaining CTV dose. Conclusion: Incorporating patient-specific displacement patterns from early in a course of treatment allows PTV adaptation for the remainder of treatment. This substantially reduces the dose to healthy tissues and thus can reduce radiation therapy–induced toxicities, improving patient outcomes

Sparing Healthy Tissue and Increasing Tumor Dose Using Bayesian Modeling of Geometric Uncertainties for Planning Target Volume Personalization

Energy Technology Data Exchange (ETDEWEB)

Herschtal, Alan, E-mail: Alan.Herschtal@petermac.org [Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne (Australia); Faculty of Health, Arts and Design, Swinburne University of Technology, Melbourne (Australia); Te Marvelde, Luc [Department of Biostatistics and Clinical Trials, Peter MacCallum Cancer Centre, Melbourne (Australia); Mengersen, Kerrie [School of Mathematical Sciences, Science and Engineering Faculty, Queensland University of Technology, Brisbane (Australia); Foroudi, Farshad [Department of Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne (Australia); The Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne (Australia); Eade, Thomas [Northern Sydney Cancer Centre, Radiation Oncology Department, Royal North Shore Hospital, St. Leonards, Sydney (Australia); Northern Clinical School, University of Sydney (Australia); Pham, Daniel [Department of Radiation Therapy, Peter MacCallum Cancer Centre, Melbourne (Australia); Caine, Hannah [Northern Sydney Cancer Centre, Radiation Oncology Department, Royal North Shore Hospital, St. Leonards, Sydney (Australia); Kron, Tomas [The Sir Peter MacCallum Department of Oncology, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne (Australia); Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne (Australia)

2015-06-01

Objective: To develop a mathematical tool that can update a patient's planning target volume (PTV) partway through a course of radiation therapy to more precisely target the tumor for the remainder of treatment and reduce dose to surrounding healthy tissue. Methods and Materials: Daily on-board imaging was used to collect large datasets of displacements for patients undergoing external beam radiation therapy for solid tumors. Bayesian statistical modeling of these geometric uncertainties was used to optimally trade off between displacement data collected from previously treated patients and the progressively accumulating data from a patient currently partway through treatment, to optimally predict future displacements for that patient. These predictions were used to update the PTV position and margin width for the remainder of treatment, such that the clinical target volume (CTV) was more precisely targeted. Results: Software simulation of dose to CTV and normal tissue for 2 real prostate displacement datasets consisting of 146 and 290 patients treated with a minimum of 30 fractions each showed that re-evaluating the PTV position and margin width after 8 treatment fractions reduced healthy tissue dose by 19% and 17%, respectively, while maintaining CTV dose. Conclusion: Incorporating patient-specific displacement patterns from early in a course of treatment allows PTV adaptation for the remainder of treatment. This substantially reduces the dose to healthy tissues and thus can reduce radiation therapy–induced toxicities, improving patient outcomes.

Mechanistic simulation of normal-tissue damage in radiotherapy-implications for dose-volume analyses

International Nuclear Information System (INIS)

Rutkowska, Eva; Baker, Colin; Nahum, Alan

2010-01-01

A radiobiologically based 3D model of normal tissue has been developed in which complications are generated when 'irradiated'. The aim is to provide insight into the connection between dose-distribution characteristics, different organ architectures and complication rates beyond that obtainable with simple DVH-based analytical NTCP models. In this model the organ consists of a large number of functional subunits (FSUs), populated by stem cells which are killed according to the LQ model. A complication is triggered if the density of FSUs in any 'critical functioning volume' (CFV) falls below some threshold. The (fractional) CFV determines the organ architecture and can be varied continuously from small (series-like behaviour) to large (parallel-like). A key feature of the model is its ability to account for the spatial dependence of dose distributions. Simulations were carried out to investigate correlations between dose-volume parameters and the incidence of 'complications' using different pseudo-clinical dose distributions. Correlations between dose-volume parameters and outcome depended on characteristics of the dose distributions and on organ architecture. As anticipated, the mean dose and V 20 correlated most strongly with outcome for a parallel organ, and the maximum dose for a serial organ. Interestingly better correlation was obtained between the 3D computer model and the LKB model with dose distributions typical for serial organs than with those typical for parallel organs. This work links the results of dose-volume analyses to dataset characteristics typical for serial and parallel organs and it may help investigators interpret the results from clinical studies.

Relative cerebral blood volume as a marker of durable tissue-at-risk viability in hyperacute ischemic stroke.

Science.gov (United States)

Cortijo, Elisa; Calleja, Ana Isabel; García-Bermejo, Pablo; Mulero, Patricia; Pérez-Fernández, Santiago; Reyes, Javier; Muñoz, Ma Fe; Martínez-Galdámez, Mario; Arenillas, Juan Francisco

2014-01-01

Selection of best responders to reperfusion therapies could be aided by predicting the duration of tissue-at-risk viability, which may be dependant on collateral circulation status. We aimed to identify the best predictor of good collateral circulation among perfusion computed tomography (PCT) parameters in middle cerebral artery (MCA) ischemic stroke and to analyze how early MCA response to intravenous thrombolysis and PCT-derived markers of good collaterals interact to determine stroke outcome. We prospectively studied patients with acute MCA ischemic stroke treated with intravenous thrombolysis who underwent PCT before treatment showing a target mismatch profile. Collateral status was assessed using a PCT source image-based score. PCT maps were quantitatively analyzed. Cerebral blood volume (CBV), cerebral blood flow, and Tmax were calculated within the hypoperfused volume and in the equivalent region of unaffected hemisphere. Occluded MCAs were monitored by transcranial Duplex to assess early recanalization. Main outcome variables were brain hypodensity volume and modified Rankin scale score at day 90. One hundred patients with MCA ischemic stroke imaged by PCT received intravenous thrombolysis, and 68 met all inclusion criteria. A relative CBV (rCBV) >0.93 emerged as the only predictor of good collaterals (odds ratio, 12.6; 95% confidence interval, 2.9-55.9; P=0.001). Early MCA recanalization was associated with better long-term outcome and lower infarct volume in patients with rCBV<0.93, but not in patients with high rCBV. None of the patients with rCBV<0.93 achieved good outcome in absence of early recanalization. High rCBV was the strongest marker of good collaterals and may characterize durable tissue-at-risk viability in hyperacute MCA ischemic stroke.

Quantitative analysis of rat adipose tissue cell recovery, and non-fat cell volume, in primary cell cultures

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Floriana Rotondo

2016-11-01

Full Text Available Background White adipose tissue (WAT is a complex, diffuse, multifunctional organ which contains adipocytes, and a large proportion of fat, but also other cell types, active in defense, regeneration and signalling functions. Studies with adipocytes often require their isolation from WAT by breaking up the matrix of collagen fibres; however, it is unclear to what extent adipocyte number in primary cultures correlates with their number in intact WAT, since recovery and viability are often unknown. Experimental Design Epididymal WAT of four young adult rats was used to isolate adipocytes with collagenase. Careful recording of lipid content of tissue, and all fraction volumes and weights, allowed us to trace the amount of initial WAT fat remaining in the cell preparation. Functionality was estimated by incubation with glucose and measurement of glucose uptake and lactate, glycerol and NEFA excretion rates up to 48 h. Non-adipocyte cells were also recovered and their sizes (and those of adipocytes were measured. The presence of non-nucleated cells (erythrocytes was also estimated. Results Cell numbers and sizes were correlated from all fractions to intact WAT. Tracing the lipid content, the recovery of adipocytes in the final, metabolically active, preparation was in the range of 70–75%. Cells showed even higher metabolic activity in the second than in the first day of incubation. Adipocytes were 7%, erythrocytes 66% and other stromal (nucleated cells 27% of total WAT cells. However, their overall volumes were 90%, 0.05%, and 0.2% of WAT. Non-fat volume of adipocytes was 1.3% of WAT. Conclusions The methodology presented here allows for a direct quantitative reference to the original tissue of studies using isolated cells. We have also found that the “live cell mass” of adipose tissue is very small: about 13 µL/g for adipocytes and 2 µL/g stromal, plus about 1 µL/g blood (the rats were killed by exsanguination. These data translate (with

Realization of fluence field modulated CT on a clinical TomoTherapy megavoltage CT system

International Nuclear Information System (INIS)

Szczykutowicz, Timothy P; Hermus, James; Geurts, Mark; Smilowitz, Jennifer

2015-01-01

The multi-leaf collimator (MLC) assembly present on TomoTherapy (Accuray, Madison WI) radiation therapy (RT) and mega voltage CT machines is well suited to perform fluence field modulated CT (FFMCT). In addition, there is a demand in the RT environment for FFMCT imaging techniques, specifically volume of interest (VOI) imaging.A clinical TomoTherapy machine was programmed to perform VOI. Four different size ROIs were placed at varying distances from isocenter. Projections intersecting the VOI received ‘full dose’ while those not intersecting the VOI received 30% of the dose (i.e. the incident fluence for non VOI projections was 30% of the incident fluence for projections intersecting the VOI). Additional scans without fluence field modulation were acquired at ‘full’ and 30% dose. The noise (pixel standard deviation) and mean CT number were measured inside the VOI region and compared between the three scans. Dose maps were generated using a dedicated TomoTherapy treatment planning dose calculator.The VOI-FFMCT technique produced an image noise 1.05, 1.00, 1.03, and 1.05 times higher than the ‘full dose’ scan for ROI sizes of 10 cm, 13 cm, 10 cm, and 6 cm respectively within the VOI region. The VOI-FFMCT technique required a total imaging dose equal to 0.61, 0.69, 0.60, and 0.50 times the ‘full dose’ acquisition dose for ROI sizes of 10 cm, 13 cm, 10 cm, and 6 cm respectively within the VOI region.Noise levels can be almost unchanged within clinically relevant VOIs sizes for RT applications while the integral imaging dose to the patient can be decreased, and/or the image quality in RT can be dramatically increased with no change in dose relative to non-FFMCT RT imaging. The ability to shift dose away from regions unimportant for clinical evaluation in order to improve image quality or reduce imaging dose has been demonstrated. This paper demonstrates that FFMCT can be performed using the MLC on a clinical TomoTherapy machine for the

Examination of the Pattern of Growth of Cerebral Tissue Volumes From Hospital Discharge to Early Childhood in Very Preterm Infants.

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Monson, Brian B; Anderson, Peter J; Matthews, Lillian G; Neil, Jeffrey J; Kapur, Kush; Cheong, Jeanie L Y; Doyle, Lex W; Thompson, Deanne K; Inder, Terrie E

2016-08-01

Smaller cerebral volumes at hospital discharge in very preterm (VPT) infants are associated with poor neurobehavioral outcomes. Brain growth from the newborn period to middle childhood has not been explored because longitudinal data have been lacking. To examine the pattern of growth of cerebral tissue volumes from hospital discharge to childhood in VPT infants and to determine perinatal risk factors for impaired brain growth and associations with neurobehavioral outcomes at 7 years. Prospective cohort study of VPT infants (childhood and outcomes in VPT infants. Low brain volumes observed in VPT infants are exaggerated at 7 years. Low brain volume in infancy is associated with long-term functional outcomes, emphasizing the persisting influence of early brain development on subsequent growth and outcomes.

Peak systolic pressure-volume relationships in man

International Nuclear Information System (INIS)

Adachi, Haruhiko; Sugihara, Hiroki; Nakagawa, Hiroaki; Katsume, Hiroshi; Ochiai, Masakazu; Ijichi, Hamao

1985-01-01

We determined the relationship between left ventricular (LV) peak systolic pressure (PSP) and end-systolic volume, non-invasively using cuff sphygmomanometry and radionuclide angiocardiography (RNA). Systolic blood pressure (SBP) measured in the arm was substituted for PSP. LV enddiastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were determined by a non-geometric method of gated RNA and recorded in three different hemodynamic states: at rest (basal state), during increased SBP after angiotensin administration (initial dose, 1-2 μg/min) and during decreased SBP after nitrate (sublingual nitroglycerin, 0.3-0.6 mg, or intravenous isosorbide dinitrate, 0.5-1.0 mg/min). The reproducibility of this method, tested in six subjects, proved to be good. Fifty-five subjects were divided into four groups based on EF at rest. The EDV and ESV were increased by angiotensin, and decreased by nitrate in all groups. EF was decreased by angiotensin and increased by nitrate. In contrast, the changes in PSP/ESVI due to these drugs remained in a narrow range in all groups. The regression lines of the PSP/ESVI relationship were almost linear and were steeper in the group with higher EF. Esub(max), the slope of the lines, was 5.75 +- 3.48 mmHg/ml/m 2 in group 1 (EF>50%), 3.16 +- 1.83 mmHg/ml/m 2 in group 2 (EF 49-40%), 2.27 +- 0.86 mmHg/ml/m 2 in group 3 (EF 39-30%) and 0.59 +- 0.50 mmHg/ml/m 2 in group 4 (EF<29%). The theoretical volume at zero pressure (VoI) did not meet in a definite value and was not related to EF at rest. Thus, the left ventricular peak systolic pressure-end-systolic volume relationship can be assessed non-invasively from radionuclide angiocardiography, which can be widely used for the evaluation of ventricular contractility, even in patients with asynergic ventricular contraction for whom echocardiography is unsuitable in measuring ventricular volume. (author)

A simple algorithm for subregional striatal uptake analysis with partial volume correction in dopaminergic PET imaging

International Nuclear Information System (INIS)

Lue Kunhan; Lin Hsinhon; Chuang Kehshih; Kao Chihhao, K.; Hsieh Hungjen; Liu Shuhsin

2014-01-01

In positron emission tomography (PET) of the dopaminergic system, quantitative measurements of nigrostriatal dopamine function are useful for differential diagnosis. A subregional analysis of striatal uptake enables the diagnostic performance to be more powerful. However, the partial volume effect (PVE) induces an underestimation of the true radioactivity concentration in small structures. This work proposes a simple algorithm for subregional analysis of striatal uptake with partial volume correction (PVC) in dopaminergic PET imaging. The PVC algorithm analyzes the separate striatal subregions and takes into account the PVE based on the recovery coefficient (RC). The RC is defined as the ratio of the PVE-uncorrected to PVE-corrected radioactivity concentration, and is derived from a combination of the traditional volume of interest (VOI) analysis and the large VOI technique. The clinical studies, comprising 11 patients with Parkinson's disease (PD) and 6 healthy subjects, were used to assess the impact of PVC on the quantitative measurements. Simulations on a numerical phantom that mimicked realistic healthy and neurodegenerative situations were used to evaluate the performance of the proposed PVC algorithm. In both the clinical and the simulation studies, the striatal-to-occipital ratio (SOR) values for the entire striatum and its subregions were calculated with and without PVC. In the clinical studies, the SOR values in each structure (caudate, anterior putamen, posterior putamen, putamen, and striatum) were significantly higher by using PVC in contrast to those without. Among the PD patients, the SOR values in each structure and quantitative disease severity ratings were shown to be significantly related only when PVC was used. For the simulation studies, the average absolute percentage error of the SOR estimates before and after PVC were 22.74% and 1.54% in the healthy situation, respectively; those in the neurodegenerative situation were 20.69% and 2

Multi-tissue partial volume quantification in multi-contrast MRI using an optimised spectral unmixing approach.

Science.gov (United States)

Collewet, Guylaine; Moussaoui, Saïd; Deligny, Cécile; Lucas, Tiphaine; Idier, Jérôme

2018-06-01

Multi-tissue partial volume estimation in MRI images is investigated with a viewpoint related to spectral unmixing as used in hyperspectral imaging. The main contribution of this paper is twofold. It firstly proposes a theoretical analysis of the statistical optimality conditions of the proportion estimation problem, which in the context of multi-contrast MRI data acquisition allows to appropriately set the imaging sequence parameters. Secondly, an efficient proportion quantification algorithm based on the minimisation of a penalised least-square criterion incorporating a regularity constraint on the spatial distribution of the proportions is proposed. Furthermore, the resulting developments are discussed using empirical simulations. The practical usefulness of the spectral unmixing approach for partial volume quantification in MRI is illustrated through an application to food analysis on the proving of a Danish pastry. Copyright © 2018 Elsevier Inc. All rights reserved.

Experimental Models Used in Fat Grafting Research for Volume Augmentation in Soft Tissue Reconstruction

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Jorge Lujan-Hernandez

2017-09-01

Full Text Available As the popularity of fat grafting research increases, animal models are being used as the source of pre-clinical experimental information for discovery and to enhance techniques. To date, animal models used in this research have not been compared to provide a standardized model. We analyzed publications from 1968–2015 to compare published accounts of animal models in fat grafting research. Data collected included: species used, graft characteristics (donor tissue, recipient area, amount injected, injection technique, time of sacrifice and quantification methods. Mice were most commonly used (56% of studies, with the “athymic nude” strain utilized most frequently (44%. Autologous fat was the most common source of grafted tissue (52%. Subcutaneous dorsum was the most common recipient site (51%. On average, 0.80±0.60 mL of fat was grafted. A single bolus technique was used in 57% of studies. Fat volume assessment was typically completed at the end of the study, occurring at less than 1 week to one year. Graft volume was quantified by weight (63%, usually in conjunction with another analysis. The results demonstrate the current heterogeneity of animal models in this research. We propose that the research community reach a consensus to allow better comparison of techniques and results. One example is the model used in our laboratory and others; this model is described in detail. Eventually, larger animal models may better translate to the human condition but, given increased financial costs and animal facility capability, should be explored when data obtained from small animal studies is exhausted or inconclusive.

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Metabolic connectivity by interregional correlation analysis using statistical parametric mapping (SPM) and FDG brain PET; methodological development and patterns of metabolic connectivity in adults

International Nuclear Information System (INIS)

Lee, Dong Soo; Oh, Jungsu S.; Lee, Jae Sung; Lee, Myung Chul; Kang, Hyejin; Kim, Heejung; Park, Hyojin

2008-01-01

Regionally connected areas of the resting brain can be detected by fluorodeoxyglucose-positron emission tomography (FDG-PET). Voxel-wise metabolic connectivity was examined, and normative data were established by performing interregional correlation analysis on statistical parametric mapping of FDG-PET data. Characteristics of seed volumes of interest (VOIs) as functional brain units were represented by their locations, sizes, and the independent methods of their determination. Seed brain areas were identified as population-based gyral VOIs (n=70) or as population-based cytoarchitectonic Brodmann areas (BA; n=28). FDG uptakes in these areas were used as independent variables in a general linear model to search for voxels correlated with average seed VOI counts. Positive correlations were searched in entire brain areas. In normal adults, one third of gyral VOIs yielded correlations that were confined to themselves, but in the others, correlated voxels extended to adjacent areas and/or contralateral homologous regions. In tens of these latter areas with extensive connectivity, correlated voxels were found across midline, and asymmetry was observed in the patterns of connectivity of left and right homologous seed VOIs. Most of the available BAs yielded correlations reaching contralateral homologous regions and/or neighboring areas. Extents of metabolic connectivity were not found to be related to seed VOI size or to the methods used to define seed VOIs. These findings indicate that patterns of metabolic connectivity of functional brain units depend on their regional locations. We propose that interregional correlation analysis of FDG-PET data offers a means of examining voxel-wise regional metabolic connectivity of the resting human brain. (orig.)

Metabolic connectivity by interregional correlation analysis using statistical parametric mapping (SPM) and FDG brain PET; methodological development and patterns of metabolic connectivity in adults

Energy Technology Data Exchange (ETDEWEB)

Lee, Dong Soo; Oh, Jungsu S.; Lee, Jae Sung; Lee, Myung Chul [Seoul National University, College of Medicine, Department of Nuclear Medicine, Jongno-gu, Seoul (Korea); Kang, Hyejin [Seoul National University, College of Medicine, Department of Nuclear Medicine, Jongno-gu, Seoul (Korea); Seoul National University, Programs in Brain and Neuroscience, Seoul (Korea); Kim, Heejung; Park, Hyojin [Seoul National University, College of Medicine, Department of Nuclear Medicine, Jongno-gu, Seoul (Korea); Seoul National University, Interdisciplinary Program in Cognitive Science, Seoul (Korea)

2008-09-15

Regionally connected areas of the resting brain can be detected by fluorodeoxyglucose-positron emission tomography (FDG-PET). Voxel-wise metabolic connectivity was examined, and normative data were established by performing interregional correlation analysis on statistical parametric mapping of FDG-PET data. Characteristics of seed volumes of interest (VOIs) as functional brain units were represented by their locations, sizes, and the independent methods of their determination. Seed brain areas were identified as population-based gyral VOIs (n=70) or as population-based cytoarchitectonic Brodmann areas (BA; n=28). FDG uptakes in these areas were used as independent variables in a general linear model to search for voxels correlated with average seed VOI counts. Positive correlations were searched in entire brain areas. In normal adults, one third of gyral VOIs yielded correlations that were confined to themselves, but in the others, correlated voxels extended to adjacent areas and/or contralateral homologous regions. In tens of these latter areas with extensive connectivity, correlated voxels were found across midline, and asymmetry was observed in the patterns of connectivity of left and right homologous seed VOIs. Most of the available BAs yielded correlations reaching contralateral homologous regions and/or neighboring areas. Extents of metabolic connectivity were not found to be related to seed VOI size or to the methods used to define seed VOIs. These findings indicate that patterns of metabolic connectivity of functional brain units depend on their regional locations. We propose that interregional correlation analysis of FDG-PET data offers a means of examining voxel-wise regional metabolic connectivity of the resting human brain. (orig.)

Dynamic PET/CT measurements of induced positron activity in a prostate cancer patient after 50-MV photon radiation therapy.

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Janek Strååt, Sara; Jacobsson, Hans; Noz, Marilyn E; Andreassen, Björn; Näslund, Ingemar; Jonsson, Cathrine

2013-01-23

The purpose of this work was to reveal the research interest value of positron emission tomography (PET) imaging in visualizing the induced tissue activity post high-energy photon radiation treatment. More specifically, the focus was on the possibility of retrieving data such as tissue composition and physical half-lives from dynamic PET acquisitions, as positron-emitting radionuclides such as 15O, 11C, and 13N are produced in vivo during radiation treatment with high-energy photons (>15 MeV). The type, amount, and distribution of induced positron-emitting radionuclides depend on the irradiated tissue cross section, the photon spectrum, and the possible perfusion-driven washout. A 62-year-old man diagnosed with prostate cancer was referred for palliative radiation treatment of the pelvis minor. A total dose of 8 Gy was given using high-energy photon beams (50 MV) with a racetrack microtron, and 7 min after the end of irradiation, the patient was positioned in a PET/computed tomography (CT) camera, and a list-mode acquisition was performed for 30 min. Two volumes of interests (VOIs) were positioned on the dynamic PET/CT images, one in the urinary bladder and the other in the subcutaneous fat. Analysis of the measured relative count rate was performed in order to compute the tissue compositions and physical half-lives in the two regions. Dynamic analysis from the two VOIs showed that the decay constants of activated oxygen and carbon could be deduced. Calculation of tissue composition from analyzing the VOI containing subcutaneous fat only moderately agreed with that of the tabulated International Commission on Radiation Units & Measurements (ICRU) data of the adipose tissue. However, the same analysis for the bladder showed a good agreement with that of the tabulated ICRU data. PET can be used in visualizing the induced activity post high-energy photon radiation treatment. Despite the very low count rate in this specific application, wherein 7 min after treatment

Facilitated assessment of tissue loss following traumatic brain injury

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Anders eHånell

2012-03-01

Full Text Available All experimental models of traumatic brain injury (TBI result in a progressive loss of brain tissue. The extent of tissue loss reflects the injury severity and can be measured to evaluate the potential neuroprotective effect of experimental treatments. Quantitation of tissue volumes is commonly performed using evenly spaced brain sections stained using routine histochemical methods and digitally captured. The brain tissue areas are then measured and the corresponding volumes are calculated using the distance between the sections. Measurements of areas are usually performed using a general purpose image analysis software and the results are then transferred to another program for volume calculations. To facilitate the measurement of brain tissue loss we developed novel algorithms which automatically separate the areas of brain tissue from the surrounding image background and identify the ventricles. We implemented these new algorithms by creating a new computer program (SectionToVolume which also has functions for image organization, image adjustments and volume calculations. We analyzed brain sections from mice subjected to severe focal TBI using both SectionToVolume and ImageJ, a commonly used image analysis program. The volume measurements made by the two programs were highly correlated and analysis using SectionToVolume required considerably less time. The inter-rater reliability was high. Given the extensive use of brain tissue loss measurements in TBI research, SectionToVolume will likely be a useful tool for TBI research. We therefore provide both the source code and the program as attachments to this article.

Serial section scanning electron microscopy (S3EM) on silicon wafers for ultra-structural volume imaging of cells and tissues.

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Horstmann, Heinz; Körber, Christoph; Sätzler, Kurt; Aydin, Daniel; Kuner, Thomas

2012-01-01

High resolution, three-dimensional (3D) representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM), complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM) using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S(3)EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm(3) volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S(3)EM), for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S(3)EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation.

Serial section scanning electron microscopy (S3EM on silicon wafers for ultra-structural volume imaging of cells and tissues.

Directory of Open Access Journals (Sweden)

Heinz Horstmann

Full Text Available High resolution, three-dimensional (3D representations of cellular ultrastructure are essential for structure function studies in all areas of cell biology. While limited subcellular volumes have been routinely examined using serial section transmission electron microscopy (ssTEM, complete ultrastructural reconstructions of large volumes, entire cells or even tissue are difficult to achieve using ssTEM. Here, we introduce a novel approach combining serial sectioning of tissue with scanning electron microscopy (SEM using a conductive silicon wafer as a support. Ribbons containing hundreds of 35 nm thick sections can be generated and imaged on the wafer at a lateral pixel resolution of 3.7 nm by recording the backscattered electrons with the in-lens detector of the SEM. The resulting electron micrographs are qualitatively comparable to those obtained by conventional TEM. S(3EM images of the same region of interest in consecutive sections can be used for 3D reconstructions of large structures. We demonstrate the potential of this approach by reconstructing a 31.7 µm(3 volume of a calyx of Held presynaptic terminal. The approach introduced here, Serial Section SEM (S(3EM, for the first time provides the possibility to obtain 3D ultrastructure of large volumes with high resolution and to selectively and repetitively home in on structures of interest. S(3EM accelerates process duration, is amenable to full automation and can be implemented with standard instrumentation.

One-month spaceflight compromises the bone microstructure, tissue-level mechanical properties, osteocyte survival and lacunae volume in mature mice skeletons.

Science.gov (United States)

Gerbaix, Maude; Gnyubkin, Vasily; Farlay, Delphine; Olivier, Cécile; Ammann, Patrick; Courbon, Guillaume; Laroche, Norbert; Genthial, Rachel; Follet, Hélène; Peyrin, Françoise; Shenkman, Boris; Gauquelin-Koch, Guillemette; Vico, Laurence

2017-06-01

The weightless environment during spaceflight induces site-specific bone loss. The 30-day Bion-M1 mission offered a unique opportunity to characterize the skeletal changes after spaceflight and an 8-day recovery period in mature male C57/BL6 mice. In the femur metaphysis, spaceflight decreased the trabecular bone volume (-64% vs. Habitat Control), dramatically increased the bone resorption (+140% vs. Habitat Control) and induced marrow adiposity invasion. At the diaphysis, cortical thinning associated with periosteal resorption was observed. In the Flight animal group, the osteocyte lacunae displayed a reduced volume and a more spherical shape (synchrotron radiation analyses), and empty lacunae were highly increased (+344% vs. Habitat Control). Tissue-level mechanical cortical properties (i.e., hardness and modulus) were locally decreased by spaceflight, whereas the mineral characteristics and collagen maturity were unaffected. In the vertebrae, spaceflight decreased the overall bone volume and altered the modulus in the periphery of the trabecular struts. Despite normalized osteoclastic activity and an increased osteoblast number, bone recovery was not observed 8 days after landing. In conclusion, spaceflight induces osteocyte death, which may trigger bone resorption and result in bone mass and microstructural deterioration. Moreover, osteocyte cell death, lacunae mineralization and fatty marrow, which are hallmarks of ageing, may impede tissue maintenance and repair.

The application of three-dimensional contrast-enhanced ultrasound to measure volume of affected tissue after HIFU treatment for localized prostate cancer

NARCIS (Netherlands)

Sedelaar, J. P.; Aarnink, R. G.; van Leenders, G. J.; Beerlage, H. P.; Debruyne, F. M.; Wijkstra, H.; de la Rosette, J. J.

2000-01-01

INTRODUCTION: Adequate monitoring of volume and location of affected tissue might provide helpful information when performing localized ablative therapy for prostate cancer. We hypothesize that the change in blood flow patterns after therapy in comparison to the blood flow pattern prior to therapy

Robust volume assessment of brain tissues for 3-dimensional fourier transformation MRI via a novel multispectral technique.

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Jyh-Wen Chai

Full Text Available A new TRIO algorithm method integrating three different algorithms is proposed to perform brain MRI segmentation in the native coordinate space, with no need of transformation to a standard coordinate space or the probability maps for segmentation. The method is a simple voxel-based algorithm, derived from multispectral remote sensing techniques, and only requires minimal operator input to depict GM, WM, and CSF tissue clusters to complete classification of a 3D high-resolution multislice-multispectral MRI data. Results showed very high accuracy and reproducibility in classification of GM, WM, and CSF in multislice-multispectral synthetic MRI data. The similarity indexes, expressing overlap between classification results and the ground truth, were 0.951, 0.962, and 0.956 for GM, WM, and CSF classifications in the image data with 3% noise level and 0% non-uniformity intensity. The method particularly allows for classification of CSF with 0.994, 0.961 and 0.996 of accuracy, sensitivity and specificity in images data with 3% noise level and 0% non-uniformity intensity, which had seldom performed well in previous studies. As for clinical MRI data, the quantitative data of brain tissue volumes aligned closely with the brain morphometrics in three different study groups of young adults, elderly volunteers, and dementia patients. The results also showed very low rates of the intra- and extra-operator variability in measurements of the absolute volumes and volume fractions of cerebral GM, WM, and CSF in three different study groups. The mean coefficients of variation of GM, WM, and CSF volume measurements were in the range of 0.03% to 0.30% of intra-operator measurements and 0.06% to 0.45% of inter-operator measurements. In conclusion, the TRIO algorithm exhibits a remarkable ability in robust classification of multislice-multispectral brain MR images, which would be potentially applicable for clinical brain volumetric analysis and explicitly promising

Comparison of standardized uptake values measured on 18F-NaF PET/CT scans using three different tube current intensities

OpenAIRE

Agnes Araujo Valadares; Paulo Schiavom Duarte; Eduardo Bechtloff Woellner; George Barberio Coura-Filho; Marcelo Tatit Sapienza; Carlos Alberto Buchpiguel

2015-01-01

Objective: To analyze standardized uptake values (SUVs) using three different tube current intensities for attenuation correction on 18FNaF PET/CT scans. Materials and Methods: A total of 254 18F-NaF PET/CT studies were analyzed using 10, 20 and 30 mAs. The SUVs were calculated in volumes of interest (VOIs) drawn on three skeletal regions, namely, right proximal humeral diaphysis (RH), right proximal femoral diaphysis (RF), and first lumbar vertebra (LV1) in a total of 712 VOIs. The analyses ...

Evaluation of two intracavitary high-dose-rate brachytherapy devices for irradiating additional and irregularly shaped volumes of breast tissue

International Nuclear Information System (INIS)

Lu, Sharon M.; Scanderbeg, Daniel J.; Barna, Patrick; Yashar, William; Yashar, Catheryn

2012-01-01

The SAVI and Contura breast brachytherapy applicators represent 2 recent advancements in brachytherapy technology that have expanded the number of women eligible for accelerated partial breast irradiation in the treatment of early-stage breast cancer. Early clinical experience with these 2 single-entry, multichannel high-dose-rate brachytherapy devices confirms their ease of use and dosimetric versatility. However, current clinical guidelines for SAVI and Contura brachytherapy may result in a smaller or less optimal volume of treated tissue compared with traditional interstitial brachytherapy. This study evaluates the feasibility of using the SAVI and Contura to irradiate larger and irregularly shaped target volumes, approaching what is treatable with the interstitial technique. To investigate whether additional tissue can be treated, 17 patients treated with the SAVI and 3 with the Contura were selected. For each patient, the planning target volume (PTV) was modified to extend 1.1 cm, 1.3 cm, and 1.5 cm beyond the tumor bed cavity. To evaluate dose conformance to an irregularly shaped target volume, 9 patients treated with the SAVI and 3 with the Contura were selected from the original 20 patients. The following asymmetric PTV margin combinations were assessed for each patient: 1.5/0.3, 1.3/0.3, and 1.1/0.3 cm. For all patients, treatment planning was performed, adopting the National Surgical Adjuvant Breast and Bowel Project guidelines, and dosimetric comparisons were made. The 6–1 and 8–1 SAVI devices can theoretically treat a maximal tissue margin of 1.5 cm and an asymmetric PTV with margins ranging from 0.3 to 1.5 cm. The 10–1 SAVI and Contura can treat a maximal margin of 1.3 cm and 1.1 cm, respectively, and asymmetric PTV with margins ranging from 0.3–1.3 cm. Compared with the Contura, the SAVI demonstrated greater dosimetric flexibility. Risk of developing excessive hot spots increased with the size of the SAVI device. Both the SAVI and Contura

Reduction in adipose tissue volume using a new high-power radiofrequency technology combined with infrared light and mechanical manipulation for body contouring.

Science.gov (United States)

Adatto, Maurice A; Adatto-Neilson, Robyn M; Morren, Grietje

2014-09-01

A growing patient demand for a youthful skin appearance with a favorable body shape has led to the recent development of new noninvasive body contouring techniques. We have previously demonstrated that the combination of bipolar radiofrequency (RF) and optical energies with tissue manipulation is an efficient reshaping modality. Here, we investigated the efficacy and safety of a new high-power version of this combined technology, in terms of adipose tissue reduction and skin tightening. Thirty-five patients received one treatment per week over 6 weeks to their abdomen/flank, buttock, or thigh areas and were followed up to 3 months post completion of the treatment protocol. This new device has an increased power in the bipolar RF, as this parameter appears to be the most important energy modality for volume reduction. Patient circumferences were measured and comparisons of baseline and post treatment outcomes were made. Diagnostic ultrasound (US) measurements were performed in 12 patients to evaluate the reduction in adipose tissue volume, and a cutometer device was used to assess improvements in skin tightening. We observed a gradual decline in patient circumferences from baseline to post six treatments. The overall body shaping effect was accompanied with improvement in skin tightening and was clearly noticeable in the comparison of the before and after treatment clinical photographs. These findings correlated with measurements of adipose tissue volume and skin firmness/elasticity using diagnostic US and cutometer, respectively. The thickness of the fat layer showed on average a 29% reduction between baseline and the 1-month follow up. The average reduction in the circumference of the abdomen/flanks, buttocks, and thighs from baseline to the 3-month follow-up was 1.4, 0.5, and 1.2 cm, respectively, and 93% of study participants demonstrated a 1-60% change in fat layer thickness. Patients subjectively described comfort and satisfaction from treatment, and 97% of

Disease and genetic contributions toward local tissue volume disturbances in schizophrenia: a tensor-based morphometry study.

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Yang, Yaling; Nuechterlein, Keith H; Phillips, Owen R; Gutman, Boris; Kurth, Florian; Dinov, Ivo; Thompson, Paul M; Asarnow, Robert F; Toga, Arthur W; Narr, Katherine L

2012-09-01

Structural brain deficits, especially frontotemporal volume reduction and ventricular enlargement, have been repeatedly reported in patients with schizophrenia. However, it remains unclear whether brain structural deformations may be attributable to disease-related or genetic factors. In this study, the structural magnetic resonance imaging data of 48 adult-onset schizophrenia patients, 65 first-degree nonpsychotic relatives of schizophrenia patients, 27 community comparison (CC) probands, and 73 CC relatives were examined using tensor-based morphometry (TBM) to isolate global and localized differences in tissue volume across the entire brain between groups. We found brain tissue contractions most prominently in frontal and temporal regions and expansions in the putamen/pallidum, and lateral and third ventricles in schizophrenia patients when compared with unrelated CC probands. Results were similar, though less prominent when patients were compared with their nonpsychotic relatives. Structural deformations observed in unaffected patient relatives compared to age-similar CC relatives were suggestive of schizophrenia-related genetic liability and were pronounced in the putamen/pallidum and medial temporal regions. Schizophrenia and genetic liability effects for the putamen/pallidum were confirmed by regions-of-interest analysis. In conclusion, TBM findings complement reports of frontal, temporal, and ventricular dysmorphology in schizophrenia and further indicate that putamen/pallidum enlargements, originally linked mainly with medication exposure in early studies, also reflect a genetic predisposition for schizophrenia. Thus, brain deformation profiles revealed in this study may help to clarify the role of specific genetic or environmental risk factors toward altered brain morphology in schizophrenia.

Calculating potential error in sodium MRI with respect to the analysis of small objects.

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Stobbe, Robert W; Beaulieu, Christian

2018-06-01

To facilitate correct interpretation of sodium MRI measurements, calculation of error with respect to rapid signal decay is introduced and combined with that of spatially correlated noise to assess volume-of-interest (VOI) 23 Na signal measurement inaccuracies, particularly for small objects. Noise and signal decay-related error calculations were verified using twisted projection imaging and a specially designed phantom with different sized spheres of constant elevated sodium concentration. As a demonstration, lesion signal measurement variation (5 multiple sclerosis participants) was compared with that predicted from calculation. Both theory and phantom experiment showed that VOI signal measurement in a large 10-mL, 314-voxel sphere was 20% less than expected on account of point-spread-function smearing when the VOI was drawn to include the full sphere. Volume-of-interest contraction reduced this error but increased noise-related error. Errors were even greater for smaller spheres (40-60% less than expected for a 0.35-mL, 11-voxel sphere). Image-intensity VOI measurements varied and increased with multiple sclerosis lesion size in a manner similar to that predicted from theory. Correlation suggests large underestimation of 23 Na signal in small lesions. Acquisition-specific measurement error calculation aids 23 Na MRI data analysis and highlights the limitations of current low-resolution methodologies. Magn Reson Med 79:2968-2977, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

VISUALIZATION OF BIOLOGICAL TISSUE IMPEDANCE PARAMETERS

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V. I. Bankov

2016-01-01

Full Text Available Objective. Investigation the opportunity for measurement of biological tissue impedance to visualize its parameters.Materials and methods. Studies were undertook on the experimental facility, consists of registrating measuring cell, constructed from flat inductors system, formed in oscillatory circuit, herewith investigated biological tissue is the part of this oscillatory circuit. An excitation of oscillatory circuit fulfilled by means of exciter inductor which forms impulse complex modulated electromagnetic field (ICM EMF. The measurement process and visualizations provided by set of certificated instruments: a digital oscillograph AKTAKOM ADS-2221MV, a digital generator АКТАКОМ AWG-4150 (both with software and a gauge RLC E7-22. Comparative dynamic studies of fixed volume and weight pig’s blood, adipose tissue, muscular tissue impedance were conducted by contact versus contactless methods. Contactless method in contrast to contact method gives opportunity to obtain the real morphological visualization of biological tissue irrespective of their nature.Results. Comparison of contact and contactless methods of impedance measurement shows that the inductance to capacitance ratio X(L / X(C was equal: 17 – for muscular tissue, 4 – for blood, 1 – for adipose tissue. It demonstrates the technical correspondence of both impedance registration methods. If propose the base relevance of X (L and X (C parameters for biological tissue impedance so contactless measurement method for sure shows insulating properties of adipose tissue and high conductivity for blood and muscular tissue in fixed volume-weight parameters. Registration of biological tissue impedance complex parameters by contactless method with the help of induced ICM EMF in fixed volume of biological tissue uncovers the most important informative volumes to characterize morphofunctional condition of biological tissue namely X (L / X (C.Conclusion. Contactless method of biological

The index of abdominal obesity as a marker of disorder of blood serum triglicerides fatty-acid spectrum in patients with diabetes mellitus type 2

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Наталія Миколаївна Кушнарьова

2015-12-01

Full Text Available Aim of research. To determine the possibility to use the visceral obesity index (VOI for diagnostics of lipid metabolism disorders in patients with diabetes mellitus (DM type 2 on the base of the study of adipose tissue and triglycerides fatty acids content in the blood serum of patients.Materials and methods. There were determined the body mass, height, waist size, blood serum  lipid fraction (triglycerides, LPHD, calculated the body mass index and VOI in 19 patients with DM type 2 older then 50 years. There were determined the content of fatty acids (palmitic С16:0, stearin С18:0, oleic С18:1 and linoleic С18:2 in triglycerides using the method of liquid-gas chromatography.Results. Examined patients were separated into 3 groups according to VOI value. There was detected that the higher VOI values in patients with diabetes mellitus type 2 (upper tertile were associated with the most intensive unfavorable changes of the fatty-acid spectrum of triglyceride fraction in the blood serum at the expense of an increase of saturated palmitic and stearin fatty acids fraction and decrease of unsaturated oleic and linoleic acids content. There were revealed the correlations between VOI and the levels of saturated and unsaturated triglyceride fatty acids.Conclusion. The calculation of VOI in patients with DM type 2 can be the useful indicator of the lipid metabolism disorder, especially the deviations of triglyceride fatty-acid spectrum

Normal tissue dose-effect models in biological dose optimisation

International Nuclear Information System (INIS)

Alber, M.

2008-01-01

Sophisticated radiotherapy techniques like intensity modulated radiotherapy with photons and protons rely on numerical dose optimisation. The evaluation of normal tissue dose distributions that deviate significantly from the common clinical routine and also the mathematical expression of desirable properties of a dose distribution is difficult. In essence, a dose evaluation model for normal tissues has to express the tissue specific volume effect. A formalism of local dose effect measures is presented, which can be applied to serial and parallel responding tissues as well as target volumes and physical dose penalties. These models allow a transparent description of the volume effect and an efficient control over the optimum dose distribution. They can be linked to normal tissue complication probability models and the equivalent uniform dose concept. In clinical applications, they provide a means to standardize normal tissue doses in the face of inevitable anatomical differences between patients and a vastly increased freedom to shape the dose, without being overly limiting like sets of dose-volume constraints. (orig.)

Dosimetric Coverage of the Prostate, Normal Tissue Sparing, and Acute Toxicity with High-Dose-Rate Brachytherapy for Large Prostate Volumes

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George Yang

2015-06-01

Full Text Available ABSTRACTPurposeTo evaluate dosimetric coverage of the prostate, normal tissue sparing, and acute toxicity with HDR brachytherapy for large prostate volumes.Materials and MethodsOne hundred and two prostate cancer patients with prostate volumes >50 mL (range: 5-29 mL were treated with high-dose-rate (HDR brachytherapy ± intensity modulated radiation therapy (IMRT to 4,500 cGy in 25 daily fractions between 2009 and 2013. HDR brachytherapy monotherapy doses consisted of two 1,350-1,400 cGy fractions separated by 2-3 weeks, and HDR brachytherapy boost doses consisted of two 950-1,150 cGy fractions separated by 4 weeks. Twelve of 32 (38% unfavorable intermediate risk, high risk, and very high risk patients received androgen deprivation therapy. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE version 4.ResultsMedian follow-up was 14 months. Dosimetric goals were achieved in over 90% of cases. Three of 102 (3% patients developed Grade 2 acute proctitis. No variables were significantly associated with Grade 2 acute proctitis. Seventeen of 102 (17% patients developed Grade 2 acute urinary retention. American Urological Association (AUA symptom score was the only variable significantly associated with Grade 2 acute urinary retention (p=0.04. There was no ≥ Grade 3 acute toxicity.ConclusionsDosimetric coverage of the prostate and normal tissue sparing were adequate in patients with prostate volumes >50 mL. Higher pre-treatment AUA symptom scores increased the relative risk of Grade 2 acute urinary retention. However, the overall incidence of acute toxicity was acceptable in patients with large prostate volumes.

Dosimetric coverage of the prostate, normal tissue sparing, and acute toxicity with high-dose-rate brachytherapy for large prostate volumes

Energy Technology Data Exchange (ETDEWEB)

Yang, George; Strom, Tobin J.; Shrinath, Kushagra; Mellon, Eric A.; Fernandez, Daniel C.; Biagioli, Matthew C. [Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL (United States); Wilder, Richard B., E-mail: mcbiagioli@yahoo.com [Cancer Treatment Centers of America, Newnan, GA (United States)

2015-05-15

Purpose: to evaluate dosimetric coverage of the prostate, normal tissue sparing, and acute toxicity with HDR brachytherapy for large prostate volumes. Materials and methods: one hundred and two prostate cancer patients with prostate volumes >50 mL (range: 5-29 mL) were treated with high-dose-rate (HDR) brachytherapy ± intensity modulated radiation therapy (IMRT) to 4,500 cGy in 25 daily fractions between 2009 and 2013. HDR brachytherapy monotherapy doses consisted of two 1,350-1,400 cGy fractions separated by 2-3 weeks, and HDR brachytherapy boost doses consisted of two 950-1,150 cGy fractions separated by 4 weeks. Twelve of 32 (38%) unfavorable intermediate risk, high risk, and very high risk patients received androgen deprivation therapy. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4. Results: median follow-up was 14 months. Dosimetric goals were achieved in over 90% of cases. Three of 102 (3%) patients developed Grade 2 acute proctitis. No variables were significantly associated with Grade 2 acute proctitis. Seventeen of 102 (17%) patients developed Grade 2 acute urinary retention. American Urological Association (AUA) symptom score was the only variable significantly associated with Grade 2 acute urinary retention (p-0.04). There was no ≥ Grade 3 acute toxicity. Conclusions: dosimetric coverage of the prostate and normal tissue sparing were adequate in patients with prostate volumes >50 mL. Higher pre-treatment AUA symptom scores increased the relative risk of Grade 2 acute urinary retention. However, the overall incidence of acute toxicity was acceptable in patients with large prostate volumes. (author)

Measuring the apparent diffusion coefficient in primary rectal tumors: is there a benefit in performing histogram analyses?

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van Heeswijk, Miriam M; Lambregts, Doenja M J; Maas, Monique; Lahaye, Max J; Ayas, Z; Slenter, Jos M G M; Beets, Geerard L; Bakers, Frans C H; Beets-Tan, Regina G H

2017-06-01

The apparent diffusion coefficient (ADC) is a potential prognostic imaging marker in rectal cancer. Typically, mean ADC values are used, derived from precise manual whole-volume tumor delineations by experts. The aim was first to explore whether non-precise circular delineation combined with histogram analysis can be a less cumbersome alternative to acquire similar ADC measurements and second to explore whether histogram analyses provide additional prognostic information. Thirty-seven patients who underwent a primary staging MRI including diffusion-weighted imaging (DWI; b0, 25, 50, 100, 500, 1000; 1.5 T) were included. Volumes-of-interest (VOIs) were drawn on b1000-DWI: (a) precise delineation, manually tracing tumor boundaries (2 expert readers), and (b) non-precise delineation, drawing circular VOIs with a wide margin around the tumor (2 non-experts). Mean ADC and histogram metrics (mean, min, max, median, SD, skewness, kurtosis, 5th-95th percentiles) were derived from the VOIs and delineation time was recorded. Measurements were compared between the two methods and correlated with prognostic outcome parameters. Median delineation time reduced from 47-165 s (precise) to 21-43 s (non-precise). The 45th percentile of the non-precise delineation showed the best correlation with the mean ADC from the precise delineation as the reference standard (ICC 0.71-0.75). None of the mean ADC or histogram parameters showed significant prognostic value; only the total tumor volume (VOI) was significantly larger in patients with positive clinical N stage and mesorectal fascia involvement. When performing non-precise tumor delineation, histogram analysis (in specific 45th ADC percentile) may be used as an alternative to obtain similar ADC values as with precise whole tumor delineation. Histogram analyses are not beneficial to obtain additional prognostic information.

A new method to study changes in microvascular blood volume in muscle and adipose tissue: Real time imaging in humans and rat

DEFF Research Database (Denmark)

Sjøberg, Kim Anker; Rattigan, Stephen; Hiscock, Natalie J

2011-01-01

We employed and evaluated a new application of contrast enhanced ultrasound for real time imaging of changes in microvascular blood volume (MVB) in tissues in females, males and rat. Continuous real time imaging was performed using contrast enhanced ultrasound to quantify infused gas filled micro...

Realistic tissue visualization using photoacoustic image

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Cho, Seonghee; Managuli, Ravi; Jeon, Seungwan; Kim, Jeesu; Kim, Chulhong

2018-02-01

Visualization methods are very important in biomedical imaging. As a technology that understands life, biomedical imaging has the unique advantage of providing the most intuitive information in the image. This advantage of biomedical imaging can be greatly improved by choosing a special visualization method. This is more complicated in volumetric data. Volume data has the advantage of containing 3D spatial information. Unfortunately, the data itself cannot directly represent the potential value. Because images are always displayed in 2D space, visualization is the key and creates the real value of volume data. However, image processing of 3D data requires complicated algorithms for visualization and high computational burden. Therefore, specialized algorithms and computing optimization are important issues in volume data. Photoacoustic-imaging is a unique imaging modality that can visualize the optical properties of deep tissue. Because the color of the organism is mainly determined by its light absorbing component, photoacoustic data can provide color information of tissue, which is closer to real tissue color. In this research, we developed realistic tissue visualization using acoustic-resolution photoacoustic volume data. To achieve realistic visualization, we designed specialized color transfer function, which depends on the depth of the tissue from the skin. We used direct ray casting method and processed color during computing shader parameter. In the rendering results, we succeeded in obtaining similar texture results from photoacoustic data. The surface reflected rays were visualized in white, and the reflected color from the deep tissue was visualized red like skin tissue. We also implemented the CUDA algorithm in an OpenGL environment for real-time interactive imaging.

Micro-morphologic changes around biophysically-stimulated titanium implants in ovariectomized rats

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Chang Ting-Ling

2007-07-01

Full Text Available Abstract Background Osteoporosis may present a risk factor in achievement of osseointegration because of its impact on bone remodeling properties of skeletal phsiology. The purpose of this study was to evaluate micro-morphological changes in bone around titanium implants exposed to mechanical and electrical-energy in osteoporotic rats. Methods Fifteen 12-week old sprague-dowley rats were ovariectomized to develop osteoporosis. After 8 weeks of healing period, two titanium implants were bilaterally placed in the proximal metaphyses of tibia. The animals were randomly divided into a control group and biophysically-stimulated two test groups with five animals in each group. In the first test group, a pulsed electromagnetic field (PEMF stimulation was administrated at a 0.2 mT 4 h/day, whereas the second group received low-magnitude high-frequency mechanical vibration (MECHVIB at 50 Hz 14 min/day. Following completion of two week treatment period, all animals were sacrificed. Bone sites including implants were sectioned, removed en bloc and analyzed using a microCT unit. Relative bone volume and bone micro-structural parameters were evaluated for 144 μm wide peri-implant volume of interest (VOI. Results Mean relative bone volume in the peri-implant VOI around implants PEMF and MECHVIB was significantly higher than of those in control (P P > .05 while the difference in trabecular-number among test and control groups was significant in all VOIs (P Conclusion Biophysical stimulation remarkably enhances bone volume around titanium implants placed in osteoporotic rats. Low-magnitude high-frequency MECHVIB is more effective than PEMF on bone healing in terms of relative bone volume.

Generating an Engineered Adipose Tissue Flap Using an External Suspension Device.

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Wan, Jinlin; Dong, Ziqing; Lei, Chen; Lu, Feng

2016-07-01

The tissue-engineering chamber technique can generate large volumes of adipose tissue, which provides a potential solution for the complex reconstruction of large soft-tissue defects. However, major drawbacks of this technique are the foreign-body reaction and the volume limitation imposed by the chamber. In this study, the authors developed a novel tissue-engineering method using a specially designed external suspension device that generates an optimized volume of adipose flap and avoids the implantation of foreign material. The rabbits were processed using two different tissue-engineering methods, the external suspension device technique and the traditional tissue-engineering chamber technique. The adipose flaps generated by the external suspension device had a normal adipose tissue structure that was as good as that generated by the traditional tissue-engineering chamber, but the flap volume was much larger. The final volume of the engineered adipose flap grew between weeks 0 and 36 from 5.1 ml to 30.7 ml in the traditional tissue-engineering chamber group and to 80.5 ml in the external suspension device group. During the generation process, there were no marked differences between the two methods in terms of structural and cellular changes of the flap, except that the flaps in the traditional tissue-engineering chamber group had a thicker capsule at the early stage. In addition, the enlarged flaps generated by the external suspension device could be reshaped into specific shapes by the implant chamber. This minimally invasive external suspension device technique can generate large-volume adipose flaps. Combined with a reshaping method, this technique should facilitate clinical application of adipose tissue engineering.

X-treme CT analysis of cancellous bone at the rotator cuff insertion in human individuals with osteoporosis: superficial versus deep quality.

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Kirchhoff, Chlodwig; Kirchhoff, Sonja; Sprecher, Christoph M; Ahrens, Philipp; Imhoff, Andreas B; Hinterwimmer, Stefan; Milz, Stefan; Braunstein, Volker

2013-03-01

Rotator cuff (RC) repair-especially in the elderly population-is problematic since the patients suffer to a high extent from bone mineral density loss at the reattachment site. Therefore, the study was primarily driven by the question whether it is possible to reach more or qualitatively better cancellous bone and thus a more stable postoperative result if anchors with greater length are used for RC repair and/or the conventional anchors are screwed deeper into the bone. In anatomical terms, the question is raised whether cancellous bone is of better quality close to or far off the RC enthesis. Axial HRqCT scans (X-tremeCT, Scanco Medical) of 36 human cadaveric humeral heads (75 ± 11 years) were performed to determine the ratio of bone volume to total volume (BV/TV), trabecular thickness (Trab Th), number of trabecles (Trab N), trabecular separation (Trab Sp) as well as non-metric indices such as connectivity density (Conn Dens) and structure model index (SMI). Within the greater tuberosity (GT), 6 volumes of interest (VOI) (A1, B1, C1, A2, B2, C2), in the lesser tuberosity (LT) 2 VOIs (D1, D2) and one control VOI in the subchondral bone were set. The analyzed bone cylinder of each VOI was divided into a superficial and a deep portion. The parameters BV/TV, Trab N, Trab Th and Conn Dens in all volumes of the GT and LT revealed higher values in the superficial portion reaching different levels of significance (p significance for the non-metric parameter SMI in no volume of the GT/LT, although the higher values were found superficially. Our data show that cancellous bone presents with decreasing bone quality when analyzing increasingly deeper portions of the bone cylinders of the GT and LT starting at the articular surface. This information seems to be crucial for shoulder surgeons, especially when treating elderly patients. Our results clearly prove that screwing in anchors to a deeper extent will not improve stability, since the deeper bone stock is of worse

Association Between Treatment at High-Volume Facilities and Improved Overall Survival in Soft Tissue Sarcomas.

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Venigalla, Sriram; Nead, Kevin T; Sebro, Ronnie; Guttmann, David M; Sharma, Sonam; Simone, Charles B; Levin, William P; Wilson, Robert J; Weber, Kristy L; Shabason, Jacob E

2018-03-15

Soft tissue sarcomas (STS) are rare malignancies that require complex multidisciplinary management. Therefore, facilities with high sarcoma case volume may demonstrate superior outcomes. We hypothesized that STS treatment at high-volume (HV) facilities would be associated with improved overall survival (OS). Patients aged ≥18 years with nonmetastatic STS treated with surgery and radiation therapy at a single facility from 2004 through 2013 were identified from the National Cancer Database. Facilities were dichotomized into HV and low-volume (LV) cohorts based on total case volume over the study period. OS was assessed using multivariable Cox regression with propensity score-matching. Patterns of care were assessed using multivariable logistic regression analysis. Of 9025 total patients, 1578 (17%) and 7447 (83%) were treated at HV and LV facilities, respectively. On multivariable analysis, high educational attainment, larger tumor size, higher grade, and negative surgical margins were statistically significantly associated with treatment at HV facilities; conversely, black race and non-metropolitan residence were negative predictors of treatment at HV facilities. On propensity score-matched multivariable analysis, treatment at HV facilities versus LV facilities was associated with improved OS (hazard ratio, 0.87, 95% confidence interval, 0.80-0.95; P = .001). Older age, lack of insurance, greater comorbidity, larger tumor size, higher tumor grade, and positive surgical margins were associated with statistically significantly worse OS. In this observational cohort study using the National Cancer Database, receipt of surgery and radiation therapy at HV facilities was associated with improved OS in patients with STS. Potential sociodemographic disparities limit access to care at HV facilities for certain populations. Our findings highlight the importance of receipt of care at HV facilities for patients with STS and warrant further study into improving access to

Molecular theory for nuclear magnetic relaxation in protein solutions and tissue; Surface diffusion and free-volume analogy

Energy Technology Data Exchange (ETDEWEB)

Kimmich, R; Nusser, W; Gneiting, T [Ulm Universitaet (Federal Republic of Germany). Sektion Kernresonanzspektroskopie

1990-04-01

A model theory is presented explaining a series of striking phenomena observed with nuclear magnetic relaxation in protein systems such as solutions or tissue. The frequency, concentration and temperature dependences of proton or deuteron relaxation times of protein solutions and tissue are explained. It is concluded that the translational diffusion of water molecules along the rugged surfaces of proteins and, to a minor degree, protein backbone fluctuations are crucial processes. The rate limiting factor of macromolecular tumbling is assumed to be given by the free water content in a certain analogy to the free-volume model of Cohen ad Turnbull. There are two characteristic water mass fractions indicating the saturation of the hydration shells and the onset of protein tumbling. A closed and relatively simple set of relaxation formulas is presented. The potentially fractal nature of the diffusion of water molecules on the protein surface is discussed. (author). 43 refs.; 4 figs.

Cerebral gray matter volume losses in essential tremor: A case-control study using high resolution tissue probability maps.

Science.gov (United States)

Cameron, Eric; Dyke, Jonathan P; Hernandez, Nora; Louis, Elan D; Dydak, Ulrike

2018-03-10

Essential tremor (ET) is increasingly recognized as a multi-dimensional disorder with both motor and non-motor features. For this reason, imaging studies are more broadly examining regions outside the cerebellar motor loop. Reliable detection of cerebral gray matter (GM) atrophy requires optimized processing, adapted to high-resolution magnetic resonance imaging (MRI). We investigated cerebral GM volume loss in ET cases using automated segmentation of MRI T1-weighted images. MRI was acquired on 47 ET cases and 36 controls. Automated segmentation and voxel-wise comparisons of volume were performed using Statistical Parametric Mapping (SPM) software. To improve upon standard protocols, the high-resolution International Consortium for Brain Mapping (ICBM) 2009a atlas and tissue probability maps were used to process each subject image. Group comparisons were performed: all ET vs. Controls, ET with head tremor (ETH) vs. Controls, and severe ET vs. An analysis of variance (ANOVA) was performed between ET with and without head tremor and controls. Age, sex, and Montreal Cognitive Assessment (MoCA) score were regressed out from each comparison. We were able to consistently identify regions of cerebral GM volume loss in ET and in ET subgroups in the posterior insula, superior temporal gyri, cingulate cortex, inferior frontal gyri and other occipital and parietal regions. There were no significant increases in GM volume in ET in any comparisons with controls. This study, which uses improved methodologies, provides evidence that GM volume loss in ET is present beyond the cerebellum, and in fact, is widespread throughout the cerebrum as well. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterisation of tissue shrinkage during microwave thermal ablation.

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Farina, Laura; Weiss, Noam; Nissenbaum, Yitzhak; Cavagnaro, Marta; Lopresto, Vanni; Pinto, Rosanna; Tosoratti, Nevio; Amabile, Claudio; Cassarino, Simone; Goldberg, S Nahum

2014-11-01

The aim of this study was to characterise changes in tissue volume during image-guided microwave ablation in order to arrive at a more precise determination of the true ablation zone. The effect of power (20-80 W) and time (1-10 min) on microwave-induced tissue contraction was experimentally evaluated in various-sized cubes of ex vivo liver (10-40 mm ± 2 mm) and muscle (20 and 40 mm ± 2 mm) embedded in agar phantoms (N = 119). Post-ablation linear and volumetric dimensions of the tissue cubes were measured and compared with pre-ablation dimensions. Subsequently, the process of tissue contraction was investigated dynamically during the ablation procedure through real-time X-ray CT scanning. Overall, substantial shrinkage of 52-74% of initial tissue volume was noted. The shrinkage was non-uniform over time and space, with observed asymmetry favouring the radial (23-43 % range) over the longitudinal (21-29%) direction. Algorithmic relationships for the shrinkage as a function of time were demonstrated. Furthermore, the smallest cubes showed more substantial and faster contraction (28-40% after 1 min), with more considerable volumetric shrinkage (>10%) in muscle than in liver tissue. Additionally, CT imaging demonstrated initial expansion of the tissue volume, lasting in some cases up to 3 min during the microwave ablation procedure, prior to the contraction phenomenon. In addition to an asymmetric substantial shrinkage of the ablated tissue volume, an initial expansion phenomenon occurs during MW ablation. Thus, complex modifications of the tissue close to a radiating antenna will likely need to be taken into account for future methods of real-time ablation monitoring.

Quantification of 18F-FDG PET images using probabilistic brain atlas: clinical application in temporal lobe epilepsy patients

International Nuclear Information System (INIS)

Kang, Keon Wook; Lee, Dong Soo; Cho, Jae Hoon; Lee, Jae Sung; Yeo, Jeong Seok; Lee, Sang Gun; Chung, June Key; Lee, Myung Chul

2000-01-01

A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). After calculating the counts in volume of interest (VOI) using the product of probability of SPAM images and counts in FDG images, asymmetric indexes(AI) were calculated and used for finding epileptogenic zones in temporal lobe epilepsy (TLE). FDG PET images from 28 surgically confirmed TLE patients and 12 age-matched controls were spatially normalized to the averaged brain MRI atlas of ICBM. The counts from normalized PET images were multiplied with the probability of 12 VOIs (superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, hippocampus, parahippocampal gyrus, and amygdala in each hemisphere) of SPAM images of Montreal Neurological Institute. Finally AI was calculated on each pair of VOI, and compared with visual assessment. If AI was deviated more than 2 standard deviation of normal controls, we considered epileptogenic zones were found successfully. The counts of VOIs in normal controls were symmetric (AI 0.05) except those of inferior temporal gyrus (p<0.01). AIs in 5 pairs of VOI excluding inferior temporal gyrus were deviated to one side in TLE (p<0.05). Lateralization was correct in 23/28 of patients by AI, but all of 28 were consistent with visual inspection. In 3 patients with normal AI was symmetric on visual inspection. In 2 patients falsely lateralized using AI, metabolism was also decreased visually on contra-lateral side. Asymmetric index obtained by the product of statistical probability anatomical map and FDG PET correlated well with visual assessment in TLE patients. SPAM is useful for quantification of VOIs in functional images

Automatic generation of absolute myocardial blood flow images using [15O]H2O and a clinical PET/CT scanner.

Science.gov (United States)

Harms, Hendrik J; Knaapen, Paul; de Haan, Stefan; Halbmeijer, Rick; Lammertsma, Adriaan A; Lubberink, Mark

2011-05-01

Parametric imaging of absolute myocardial blood flow (MBF) using [(15)O]H(2)O enables determination of MBF with high spatial resolution. The aim of this study was to develop a method for generating reproducible, high-quality and quantitative parametric MBF images with minimal user intervention. Nineteen patients referred for evaluation of MBF underwent rest and adenosine stress [(15)O]H(2)O positron emission tomography (PET) scans. Ascending aorta and right ventricular (RV) cavity volumes of interest (VOIs) were used as input functions. Implementation of a basis function method (BFM) of the single-tissue model with an additional correction for RV spillover was used to generate parametric images. The average segmental MBF derived from parametric images was compared with MBF obtained using nonlinear least-squares regression (NLR) of VOI data. Four segmentation algorithms were evaluated for automatic extraction of input functions. Segmental MBF obtained using these input functions was compared with MBF obtained using manually defined input functions. The average parametric MBF showed a high agreement with NLR-derived MBF [intraclass correlation coefficient (ICC) = 0.984]. For each segmentation algorithm there was at least one implementation that yielded high agreement (ICC > 0.9) with manually obtained input functions, although MBF calculated using each algorithm was at least 10% higher. Cluster analysis with six clusters yielded the highest agreement (ICC = 0.977), together with good segmentation reproducibility (coefficient of variation of MBF generated automatically using cluster analysis and a implementation of a BFM of the single-tissue model with additional RV spillover correction.

Hierarchical imaging: a new concept for targeted imaging of large volumes from cells to tissues.

Science.gov (United States)

Wacker, Irene; Spomer, Waldemar; Hofmann, Andreas; Thaler, Marlene; Hillmer, Stefan; Gengenbach, Ulrich; Schröder, Rasmus R

2016-12-12

volume data at different levels of resolution can yield comprehensive information, including statistics, morphology and organization of cells and tissue. We predict, that hierarchical imaging will be a first step in tackling the big data issue inevitably connected with volume EM.

Impact of target point deviations on control and complication probabilities in stereotactic radiosurgery of AVMs and metastases

International Nuclear Information System (INIS)

Treuer, Harald; Kocher, Martin; Hoevels, Moritz; Hunsche, Stefan; Luyken, Klaus; Maarouf, Mohammad; Voges, Juergen; Mueller, Rolf-Peter; Sturm, Volker

2006-01-01

Objective: Determination of the impact of inaccuracies in the determination and setup of the target point in stereotactic radiosurgery (SRS) on the expectable complication and control probabilities. Methods: Two randomized samples of patients with arteriovenous malformation (AVM) (n = 20) and with brain metastases (n = 20) treated with SRS were formed, and the probability for complete obliteration (COP) or complete remission (CRP), the size of the 10 Gy-volume in the brain tissue (VOI10), and the probability for radiation necrosis (NTCP) were calculated. The dose-effect relations for COP and CRP were fitted to clinical data. Target point deviations were simulated through random vectors and the resulting probabilities and volumes were calculated and compared with the values of the treatment plan. Results: The decrease of the relative value of the control probabilities at 1 mm target point deviation was up to 4% for AVMs and up to 10% for metastases. At 2 mm the median decrease was 5% for AVMs and 9% for metastases. The value for the target point deviation, at which COP and CRP decreased about 0.05 in 90% of the cases, was 1.3 mm. The increase of NTCP was maximally 0.0025 per mm target point deviation for AVMs and 0.0035/mm for metastases. The maximal increase of VOI10 was 0.7 cm 3 /mm target point deviation in both patient groups. Conclusions: The upper limit for tolerable target point deviations is at 1.3 mm. If this value cannot be achieved during the system test, a supplementary safety margin should be applied for the definition of the target volume. A better accuracy level is desirable, in order to ensure optimal chances for the success of the treatment. The target point precision is less important for the minimization of the probability of radiation necroses

Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes

International Nuclear Information System (INIS)

Famiano, M.A.

1997-01-01

A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time (∼1 micros to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, 137 Cs gamma rays, and electrons from a 90 Sr/ 90 Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired

Pulmonary nodule registration in serial CT scans based on rib anatomy and nodule template matching

International Nuclear Information System (INIS)

Shi Jiazheng; Sahiner, Berkman; Chan, H.-P.; Hadjiiski, Lubomir; Zhou, C.; Cascade, Philip N.; Bogot, Naama; Kazerooni, Ella A.; Wu, Y.-T.; Wei, J.

2007-01-01

An automated method is being developed in order to identify corresponding nodules in serial thoracic CT scans for interval change analysis. The method uses the rib centerlines as the reference for initial nodule registration. A spatially adaptive rib segmentation method first locates the regions where the ribs join the spine, which define the starting locations for rib tracking. Each rib is tracked and locally segmented by expectation-maximization. The ribs are automatically labeled, and the centerlines are estimated using skeletonization. For a given nodule in the source scan, the closest three ribs are identified. A three-dimensional (3D) rigid affine transformation guided by simplex optimization aligns the centerlines of each of the three rib pairs in the source and target CT volumes. Automatically defined control points along the centerlines of the three ribs in the source scan and the registered ribs in the target scan are used to guide an initial registration using a second 3D rigid affine transformation. A search volume of interest (VOI) is then located in the target scan. Nodule candidate locations within the search VOI are identified as regions with high Hessian responses. The initial registration is refined by searching for the maximum cross-correlation between the nodule template from the source scan and the candidate locations. The method was evaluated on 48 CT scans from 20 patients. Experienced radiologists identified 101 pairs of corresponding nodules. Three metrics were used for performance evaluation. The first metric was the Euclidean distance between the nodule centers identified by the radiologist and the computer registration, the second metric was a volume overlap measure between the nodule VOIs identified by the radiologist and the computer registration, and the third metric was the hit rate, which measures the fraction of nodules whose centroid computed by the computer registration in the target scan falls within the VOI identified by the

Quantification of Tumor Vessels in Glioblastoma Patients Using Time-of-Flight Angiography at 7 Tesla: A Feasibility Study

Science.gov (United States)

Radbruch, Alexander; Eidel, Oliver; Wiestler, Benedikt; Paech, Daniel; Burth, Sina; Kickingereder, Philipp; Nowosielski, Martha; Bäumer, Philipp; Wick, Wolfgang; Schlemmer, Heinz-Peter; Bendszus, Martin; Ladd, Mark; Nagel, Armin Michael; Heiland, Sabine

2014-01-01

Purpose To analyze if tumor vessels can be visualized, segmented and quantified in glioblastoma patients with time of flight (ToF) angiography at 7 Tesla and multiscale vessel enhancement filtering. Materials and Methods Twelve patients with newly diagnosed glioblastoma were examined with ToF angiography (TR = 15 ms, TE = 4.8 ms, flip angle = 15°, FOV = 160×210 mm2, voxel size: 0.31×0.31×0.40 mm3) on a whole-body 7 T MR system. A volume of interest (VOI) was placed within the border of the contrast enhancing part on T1-weighted images of the glioblastoma and a reference VOI was placed in the non-affected contralateral white matter. Automated segmentation and quantification of vessels within the two VOIs was achieved using multiscale vessel enhancement filtering in ImageJ. Results Tumor vessels were clearly visible in all patients. When comparing tumor and the reference VOI, total vessel surface (45.3±13.9 mm2 vs. 29.0±21.0 mm2 (pTesla MRI enables characterization and quantification of the internal vascular morphology of glioblastoma and may be used for the evaluation of therapy response within future studies. PMID:25415327

Quantification of {sup 18}F-FDG PET images using probabilistic brain atlas: clinical application in temporal lobe epilepsy patients

Energy Technology Data Exchange (ETDEWEB)

Kang, Keon Wook; Lee, Dong Soo; Cho, Jae Hoon; Lee, Jae Sung; Yeo, Jeong Seok; Lee, Sang Gun; Chung, June Key; Lee, Myung Chul [Seoul National Univ., Seoul (Korea, Republic of)

2000-07-01

A probabilistic atlas of the human brain (Statistical Probability Anatomical Maps: SPAM) was developed by the international consortium for brain mapping (ICBM). After calculating the counts in volume of interest (VOI) using the product of probability of SPAM images and counts in FDG images, asymmetric indexes(AI) were calculated and used for finding epileptogenic zones in temporal lobe epilepsy (TLE). FDG PET images from 28 surgically confirmed TLE patients and 12 age-matched controls were spatially normalized to the averaged brain MRI atlas of ICBM. The counts from normalized PET images were multiplied with the probability of 12 VOIs (superior temporal gyrus, middle temporal gyrus, inferior temporal gyrus, hippocampus, parahippocampal gyrus, and amygdala in each hemisphere) of SPAM images of Montreal Neurological Institute. Finally AI was calculated on each pair of VOI, and compared with visual assessment. If AI was deviated more than 2 standard deviation of normal controls, we considered epileptogenic zones were found successfully. The counts of VOIs in normal controls were symmetric (AI <6%, paired t-test p>0.05) except those of inferior temporal gyrus (p<0.01). AIs in 5 pairs of VOI excluding inferior temporal gyrus were deviated to one side in TLE (p<0.05). Lateralization was correct in 23/28 of patients by AI, but all of 28 were consistent with visual inspection. In 3 patients with normal AI was symmetric on visual inspection. In 2 patients falsely lateralized using AI, metabolism was also decreased visually on contra-lateral side. Asymmetric index obtained by the product of statistical probability anatomical map and FDG PET correlated well with visual assessment in TLE patients. SPAM is useful for quantification of VOIs in functional images.

Translational and Brownian motion in laser-Doppler flowmetry of large tissue volumes

International Nuclear Information System (INIS)

Binzoni, T; Leung, T S; Seghier, M L; Delpy, D T

2004-01-01

This study reports the derivation of a precise mathematical relationship existing between the different p-moments of the power spectrum of the photoelectric current, obtained from a laser-Doppler flowmeter (LDF), and the red blood cell speed. The main purpose is that both the Brownian (defining the 'biological zero') and the translational movements are taken into account, clarifying in this way what the exact contribution of each parameter is to the LDF derived signals. The derivation of the equations is based on the quasi-elastic scattering theory and holds for multiple scattering (i.e. measurements in large tissue volumes and/or very high red blood cell concentration). The paper also discusses why experimentally there exists a range in which the relationship between the first moment of the power spectrum and the average red blood cells speed may be considered as 'linear' and what are the physiological determinants that can result in nonlinearity. A correct way to subtract the biological zero from the LDF data is also proposed. The findings should help in the design of improved LDF instruments and in the interpretation of experimental data

Preliminary evaluation of lung care software of 16-slice helical CT in the study of pulmonary nodules

International Nuclear Information System (INIS)

Song Wei; Jin Zhengyu; Yan Hongzhen; Wang Yun; Zhang Yunqing; Wang Linhui; Zhu Haifeng; Liang Jixiang; Qi Bing

2005-01-01

Objective: To evaluate the auxiliary diagnostic ability and applicability of the Lung Care software for the study of the pulmonary nodules. Methods: Fifty-six patients underwent low-dose CT scan with 1.5 mm collimation, 4 mm reconstruction interval, and 4 mm reconstruction slice in group A, and with 1.5 mm collimation, 2 mm reconstruction interval, and 2 mm reconstruction slice in group B. 12 patients underwent low-dose CT with 0.75 mm collimation, 0.75 mm reconstruction interval, and 0.75 mm reconstruction slice in group C. The nodules detected in groups A, B, and C were analyzed by r-MPR or VOI of the Lung Care software to distinguish the true pulmonary nodules from the vessels. The volume and density distribution of the true pulmonary nodules in groups A, B, and C were measured with the Lung Care software. Results: It was difficult to observe the diffuse pulmonary nodules by r-MPR or VOI of the Lung Care software. The images of each patient in group C were too many to be applied in the clinic. There was statistically consistent in the observation of pulmonary nodules between r-MPR and VOI, but the coincidence was not good (Kappa=0.369, P=0.002). There was statistically significant difference in showing faint nodules between r-MPR and VOI (P=0.001), r-MPR was better than VOI. There was statistically significant difference between group A and B in showing = 3.886, P=0.045), but no statistically significant difference in showing 5-10 mm nodules (χ 2 =0.170, P=0.680). The volume and density distribution of most 5 - ≤20 mm nodules were successfully measured with the Lung Care software, whereas those of most 2 =5.811, P=0.016) and 5-10 mm nodules (χ 2 =13.500, P 10 - ≤20 mm nodules (χ 2 =0.000, P=1.000). Conclusion: For distinguishing the true pulmonary nodules from others, the Lung Care software is suitable for the well-edged pulmonary nodules and most faint nodules, but not suitable for the nodules such as ground-glass opacity. For measuring the volume and

Individual patient dosimetry using quantitative SPECT imaging

International Nuclear Information System (INIS)

Gonzalez, J.; Oliva, J.; Baum, R.; Fisher, S.

2002-01-01

An approach is described to provide individual patient dosimetry for routine clinical use. Accurate quantitative SPECT imaging was achieved using appropriate methods. The volume of interest (VOI) was defined semi-automatically using a fixed threshold value obtained from phantom studies. The calibration factor to convert the voxel counts from SPECT images into activity values was determine from calibrated point source using the same threshold value as in phantom studies. From selected radionuclide the dose within and outside a sphere of voxel dimension at different distances was computed through dose point-kernels to obtain a discrete absorbed dose kernel representation around the volume source with uniform activity distribution. The spatial activity distribution from SPECT imaging was convolved with this kernel representation using the discrete Fourier transform method to yield three-dimensional absorbed dose rate distribution. The accuracy of dose rates calculation was validated by software phantoms. The absorbed dose was determined by integration of the dose rate distribution for each volume of interest (VOI). Parameters for treatment optimization such as dose rate volume histograms and dose rate statistic are provided. A patient example was used to illustrate our dosimetric calculations

Normal tissue complication probabilities: dependence on choice of biological model and dose-volume histogram reduction scheme

International Nuclear Information System (INIS)

Moiseenko, Vitali; Battista, Jerry; Van Dyk, Jake

2000-01-01

Purpose: To evaluate the impact of dose-volume histogram (DVH) reduction schemes and models of normal tissue complication probability (NTCP) on ranking of radiation treatment plans. Methods and Materials: Data for liver complications in humans and for spinal cord in rats were used to derive input parameters of four different NTCP models. DVH reduction was performed using two schemes: 'effective volume' and 'preferred Lyman'. DVHs for competing treatment plans were derived from a sample DVH by varying dose uniformity in a high dose region so that the obtained cumulative DVHs intersected. Treatment plans were ranked according to the calculated NTCP values. Results: Whenever the preferred Lyman scheme was used to reduce the DVH, competing plans were indistinguishable as long as the mean dose was constant. The effective volume DVH reduction scheme did allow us to distinguish between these competing treatment plans. However, plan ranking depended on the radiobiological model used and its input parameters. Conclusions: Dose escalation will be a significant part of radiation treatment planning using new technologies, such as 3-D conformal radiotherapy and tomotherapy. Such dose escalation will depend on how the dose distributions in organs at risk are interpreted in terms of expected complication probabilities. The present study indicates considerable variability in predicted NTCP values because of the methods used for DVH reduction and radiobiological models and their input parameters. Animal studies and collection of standardized clinical data are needed to ascertain the effects of non-uniform dose distributions and to test the validity of the models currently in use

Epicardial adipose tissue volume and adipocytokine imbalance are strongly linked to human coronary atherosclerosis.

Science.gov (United States)

Shimabukuro, Michio; Hirata, Yoichiro; Tabata, Minoru; Dagvasumberel, Munkhbaatar; Sato, Hiromi; Kurobe, Hirotsugu; Fukuda, Daiju; Soeki, Takeshi; Kitagawa, Tetsuya; Takanashi, Shuichiro; Sata, Masataka

2013-05-01

The impact of epicardial adipose tissue (EAT) over abdominal or overall adiposity on coronary artery disease (CAD) is currently unknown. We compared the association among EAT volume (EATV), cytokine/adipocytokine profiles in EAT and subcutaneous fat, and atherogenic CAD. Paired samples were obtained from EAT and subcutaneous adipose tissue during elective cardiac surgery for CAD (n=50) or non-CAD (n=50). EATV was the sum of cross-sectional EAT areas, and visceral and subcutaneous fat areas were determined at the umbilicus level on computed tomography scans. CD68(+), CD11c(+), and CD206(+) cells were counted using immunohistochemical staining. Cytokine/adipocytokine expression was evaluated using quantitative real-time polymerase chain reaction. Multivariate analysis indicated that male sex, age, diabetes mellitus, high triglycerides, and low high-density lipoprotein cholesterol, and EATV index (EATV/body surface area, cm(3)/m(2)) were significant CAD predictors (corrected R(2)=0.401; PEATV index positively correlated with the CD68(+) and CD11c(+) cell numbers and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3), interleukin-1β, and interleukin-1R expression; and negatively correlated with adiponectin expression in EAT. A multivariate analysis model, including CD68(+) cells and interleukin-1β, and adiponectin expression in EAT strongly predicted CAD (corrected R(2)=0.756; PEATV and macrophage and cytokine/adipocytokine signals in EAT strongly correlated with CAD. Our findings suggest that EATV and adipocytokine imbalance are strongly linked to human coronary atherosclerosis.

Dynamic contrast-enhanced micro-CT on mice with mammary carcinoma for the assessment of antiangiogenic therapy response

Energy Technology Data Exchange (ETDEWEB)

Eisa, Fabian [University of Erlangen-Nuremberg, Institute of Medical Physics, Erlangen (Germany); University of Erlangen-Nuremberg, Graduate School in Advanced Optical Technologies (SAOT), Erlangen (Germany); Brauweiler, Robert; Hupfer, Martin; Nowak, Tristan; Kalender, Willi A. [University of Erlangen-Nuremberg, Institute of Medical Physics, Erlangen (Germany); Lotz, Laura; Hoffmann, Inge; Dittrich, Ralf; Beckmann, Matthias W. [University of Erlangen-Nuremberg, OB/GYN, University Hospital Erlangen, Erlangen (Germany); Wachter, David [University Hospital Erlangen, Institute of Pathology, Erlangen (Germany); Jost, Gregor; Pietsch, Hubertus [Bayer Pharma AG, Berlin (Germany)

2012-04-15

To evaluate the potential of in vivo dynamic contrast-enhanced micro-computed tomography (DCE micro-CT) for the assessment of antiangiogenic drug therapy response of mice with mammary carcinoma. 20 female mice with implanted MCF7 tumours were split into control group and therapy group treated with a known effective antiangiogenic drug. All mice underwent DCE micro-CT for the 3D analysis of functional parameters (relative blood volume [rBV], vascular permeability [K], area under the time-enhancement curve [AUC]) and morphology. All parameters were determined for total, peripheral and central tumour volumes of interest (VOIs). Immunohistochemistry was performed to characterise tumour vascularisation. 3D dose distributions were determined. The mean AUCs were significantly lower in therapy with P values of 0.012, 0.007 and 0.023 for total, peripheral and central tumour VOIs. K and rBV showed significant differences for the peripheral (P{sub per}{sup K} = 0.032, P{sub per}{sup rBV} = 0.029), but not for the total and central tumour VOIs (P{sub total}{sup K} = 0.108, P{sub central}{sup K} = 0.246, P{sub total}{sup rBV} = 0.093, P{sub central}{sup rBV} = 0.136). Mean tumour volume was significantly smaller in therapy (P{sub in} {sub vivo} = 0.001, P{sub ex} {sub vivo} = 0.005). Histology revealed greater vascularisation in the controls and central tumour necrosis. Doses ranged from 150 to 300 mGy. This study indicates the great potential of DCE micro-CT for early in vivo assessment of antiangiogenic drug therapy response. (orig.)

Pulmonary vessel segmentation utilizing curved planar reformation and optimal path finding (CROP) in computed tomographic pulmonary angiography (CTPA) for CAD applications

Science.gov (United States)

Zhou, Chuan; Chan, Heang-Ping; Kuriakose, Jean W.; Chughtai, Aamer; Wei, Jun; Hadjiiski, Lubomir M.; Guo, Yanhui; Patel, Smita; Kazerooni, Ella A.

2012-03-01

Vessel segmentation is a fundamental step in an automated pulmonary embolism (PE) detection system. The purpose of this study is to improve the segmentation scheme for pulmonary vessels affected by PE and other lung diseases. We have developed a multiscale hierarchical vessel enhancement and segmentation (MHES) method for pulmonary vessel tree extraction based on the analysis of eigenvalues of Hessian matrices. However, it is difficult to segment the pulmonary vessels accurately under suboptimal conditions, such as vessels occluded by PEs, surrounded by lymphoid tissues or lung diseases, and crossing with other vessels. In this study, we developed a new vessel refinement method utilizing curved planar reformation (CPR) technique combined with optimal path finding method (MHES-CROP). The MHES segmented vessels straightened in the CPR volume was refined using adaptive gray level thresholding where the local threshold was obtained from least-square estimation of a spline curve fitted to the gray levels of the vessel along the straightened volume. An optimal path finding method based on Dijkstra's algorithm was finally used to trace the correct path for the vessel of interest. Two and eight CTPA scans were randomly selected as training and test data sets, respectively. Forty volumes of interest (VOIs) containing "representative" vessels were manually segmented by a radiologist experienced in CTPA interpretation and used as reference standard. The results show that, for the 32 test VOIs, the average percentage volume error relative to the reference standard was improved from 32.9+/-10.2% using the MHES method to 9.9+/-7.9% using the MHES-CROP method. The accuracy of vessel segmentation was improved significantly (pvolume between the automated segmentation and the reference standard was improved from 0.919 to 0.988. Quantitative comparison of the MHES method and the MHES-CROP method with the reference standard was also evaluated by the Bland-Altman plot. This preliminary

Discrimination of dementia with Lewy bodies from Alzheimer's disease using voxel-based morphometry of white matter by statistical parametric mapping 8 plus diffeomorphic anatomic registration through exponentiated Lie algebra.

Science.gov (United States)

Nakatsuka, Tomoya; Imabayashi, Etsuko; Matsuda, Hiroshi; Sakakibara, Ryuji; Inaoka, Tsutomu; Terada, Hitoshi

2013-05-01

The purpose of this study was to identify brain atrophy specific for dementia with Lewy bodies (DLB) and to evaluate the discriminatory performance of this specific atrophy between DLB and Alzheimer's disease (AD). We retrospectively reviewed 60 DLB and 30 AD patients who had undergone 3D T1-weighted MRI. We randomly divided the DLB patients into two equal groups (A and B). First, we obtained a target volume of interest (VOI) for DLB-specific atrophy using correlation analysis of the percentage rate of significant whole white matter (WM) atrophy calculated using the Voxel-based Specific Regional Analysis System for Alzheimer's Disease (VSRAD) based on statistical parametric mapping 8 (SPM8) plus diffeomorphic anatomic registration through exponentiated Lie algebra, with segmented WM images in group A. We then evaluated the usefulness of this target VOI for discriminating the remaining 30 DLB patients in group B from the 30 AD patients. Z score values in this target VOI obtained from VSRAD were used as the determinant in receiver operating characteristic (ROC) analysis. Specific target VOIs for DLB were determined in the right-side dominant dorsal midbrain, right-side dominant dorsal pons, and bilateral cerebellum. ROC analysis revealed that the target VOI limited to the midbrain exhibited the highest area under the ROC curves of 0.75. DLB patients showed specific atrophy in the midbrain, pons, and cerebellum. Midbrain atrophy demonstrated the highest power for discriminating DLB and AD. This approach may be useful for determining the contributions of DLB and AD pathologies to the dementia syndrome.

Comparison of the image-derived radioactivity and blood-sample radioactivity for estimating the clinical indicators of the efficacy of boron neutron capture therapy (BNCT): 4-borono-2-18F-fluoro-phenylalanine (FBPA) PET study.

Science.gov (United States)

Isohashi, Kayako; Shimosegawa, Eku; Naka, Sadahiro; Kanai, Yasukazu; Horitsugi, Genki; Mochida, Ikuko; Matsunaga, Keiko; Watabe, Tadashi; Kato, Hiroki; Tatsumi, Mitsuaki; Hatazawa, Jun

2016-12-01

In boron neutron capture therapy (BNCT), positron emission tomography (PET) with 4-borono-2- 18 F-fluoro-phenylalanine (FBPA) is the only method to estimate an accumulation of 10 B to target tumor and surrounding normal tissue after administering 10 B carrier of L-paraboronophenylalanine and to search the indication of BNCT for individual patient. Absolute concentration of 10 B in tumor has been estimated by multiplying 10 B concentration in blood during BNCT by tumor to blood radioactivity (T/B) ratio derived from FBPA PET. However, the method to measure blood radioactivity either by blood sampling or image data has not been standardized. We compared image-derived blood radioactivity of FBPA with blood sampling data and studied appropriate timing and location for measuring image-derived blood counts. We obtained 7 repeated whole-body PET scans in five healthy subjects. Arterialized venous blood samples were obtained from the antecubital vein, heated in a heating blanket. Time-activity curves (TACs) of image-derived blood radioactivity were obtained using volumes of interest (VOIs) over ascending aorta, aortic arch, pulmonary artery, left and right ventricles, inferior vena cava, and abdominal aorta. Image-derived blood radioactivity was compared with those measured by blood sampling data in each location. Both the TACs of blood sampling radioactivity in each subject, and the TACs of image-derived blood radioactivity showed a peak within 5 min after the tracer injection, and promptly decreased soon thereafter. Linear relationship was found between blood sampling radioactivity and image-derived blood radioactivity in all the VOIs at any timing of data sampling (p radioactivity measured in the left and right ventricles 30 min after injection showed high correlation with blood radioactivity. Image-derived blood radioactivity was lower than blood sampling radioactivity data by 20 %. Reduction of blood radioactivity of FBPA in left ventricle after 30 min of FBPA

Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study

International Nuclear Information System (INIS)

Juneja, Prabhjot; Harris, Emma J.; Kirby, Anna M.; Evans, Philip M.

2012-01-01

Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue segmentation

Adaptive Breast Radiation Therapy Using Modeling of Tissue Mechanics: A Breast Tissue Segmentation Study

Energy Technology Data Exchange (ETDEWEB)

Juneja, Prabhjot, E-mail: Prabhjot.Juneja@icr.ac.uk [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom); Harris, Emma J. [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom); Kirby, Anna M. [Department of Academic Radiotherapy, Royal Marsden National Health Service Foundation Trust, Sutton (United Kingdom); Evans, Philip M. [Joint Department of Physics, Institute of Cancer Research, Sutton (United Kingdom)

2012-11-01

Purpose: To validate and compare the accuracy of breast tissue segmentation methods applied to computed tomography (CT) scans used for radiation therapy planning and to study the effect of tissue distribution on the segmentation accuracy for the purpose of developing models for use in adaptive breast radiation therapy. Methods and Materials: Twenty-four patients receiving postlumpectomy radiation therapy for breast cancer underwent CT imaging in prone and supine positions. The whole-breast clinical target volume was outlined. Clinical target volumes were segmented into fibroglandular and fatty tissue using the following algorithms: physical density thresholding; interactive thresholding; fuzzy c-means with 3 classes (FCM3) and 4 classes (FCM4); and k-means. The segmentation algorithms were evaluated in 2 stages: first, an approach based on the assumption that the breast composition should be the same in both prone and supine position; and second, comparison of segmentation with tissue outlines from 3 experts using the Dice similarity coefficient (DSC). Breast datasets were grouped into nonsparse and sparse fibroglandular tissue distributions according to expert assessment and used to assess the accuracy of the segmentation methods and the agreement between experts. Results: Prone and supine breast composition analysis showed differences between the methods. Validation against expert outlines found significant differences (P<.001) between FCM3 and FCM4. Fuzzy c-means with 3 classes generated segmentation results (mean DSC = 0.70) closest to the experts' outlines. There was good agreement (mean DSC = 0.85) among experts for breast tissue outlining. Segmentation accuracy and expert agreement was significantly higher (P<.005) in the nonsparse group than in the sparse group. Conclusions: The FCM3 gave the most accurate segmentation of breast tissues on CT data and could therefore be used in adaptive radiation therapy-based on tissue modeling. Breast tissue

Volumetric quantitative characterization of human patellar cartilage with topological and geometrical features on phase-contrast X-ray computed tomography.

Science.gov (United States)

Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Wismüller, Axel

2015-11-01

Phase-contrast X-ray computed tomography (PCI-CT) has attracted significant interest in recent years for its ability to provide significantly improved image contrast in low absorbing materials such as soft biological tissue. In the research context of cartilage imaging, previous studies have demonstrated the ability of PCI-CT to visualize structural details of human patellar cartilage matrix and capture changes to chondrocyte organization induced by osteoarthritis. This study evaluates the use of geometrical and topological features for volumetric characterization of such chondrocyte patterns in the presence (or absence) of osteoarthritic damage. Geometrical features derived from the scaling index method (SIM) and topological features derived from Minkowski Functionals were extracted from 1392 volumes of interest (VOI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. These features were subsequently used in a machine learning task with support vector regression to classify VOIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver operating characteristic curve (AUC). Our results show that the classification performance of SIM-derived geometrical features (AUC: 0.90 ± 0.09) is significantly better than Minkowski Functionals volume (AUC: 0.54 ± 0.02), surface (AUC: 0.72 ± 0.06), mean breadth (AUC: 0.74 ± 0.06) and Euler characteristic (AUC: 0.78 ± 0.04) (p < 10(-4)). These results suggest that such geometrical features can provide a detailed characterization of the chondrocyte organization in the cartilage matrix in an automated manner, while also enabling classification of cartilage as healthy or osteoarthritic with high accuracy. Such features could potentially serve as diagnostic imaging markers for evaluating osteoarthritis progression and its response to different therapeutic intervention strategies.

Formation of tissue factor activity following incubation of recombinant human tissue factor apoprotein with plasma lipoproteins

International Nuclear Information System (INIS)

Sakai, T.; Kisiel, W.

1990-01-01

Incubation of recombinant human tissue factor apoprotein (Apo-TF) with human plasma decreased the recalcified clotting time of this plasma in a time-and dose-dependent manner suggesting relipidation of the Apo-TF by plasma lipoproteins. Incubation of Apo-TF with purified preparations of human very low density, low density and high density lipoproteins resulted in tissue factor activity in a clotting assay. The order of effectiveness was VLDL greater than LDL much greater than HDL. Tissue factor activity generated by incubation of a fixed amount of Apo-TF with plasma lipoproteins was lipoprotein concentration-dependent and saturable. The association of Apo-TF with lipoprotein particles was supported by gel filtration studies in which 125 I-Apo-TF coeluted with the plasma lipoprotein in the void volume of a Superose 6 column in the presence and absence of calcium ions. In addition, void-volume Apo-TF-lipoprotein fractions exhibited tissue factor activity. These results suggest that the factor VIII-bypassing activity of bovine Apo-TF observed in a canine hemophilic model may be due, in part, to its association with plasma lipoproteins and expression of functional tissue factor activity

Gender-linked impact of epicardial adipose tissue volume in patients who underwent coronary artery bypass graft surgery or non-coronary valve surgery

OpenAIRE

Maimaituxun, Gulinu; Shimabukuro, Michio; Salim, Hotimah Masdan; Tabata, Minoru; Yuji, Daisuke; Morimoto, Yoshihisa; Akasaka, Takeshi; Matsuura, Tomomi; Yagi, Shusuke; Fukuda, Daiju; Yamada, Hirotsugu; Soeki, Takeshi; Sugimoto, Takaki; Tanaka, Masashi; Takanashi, Shuichiro

2017-01-01

Background Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD) are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV) in patients undergoing coronary artery bypass grafting (CABG) remains unknown. Methods Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57) who underwent CABG or non-coronary valvular surgery ...

Association between epicardial adipose tissue volumes on 3-dimensional reconstructed CT images and recurrence of atrial fibrillation after catheter ablation

International Nuclear Information System (INIS)

Nagashima, Koichi; Okumura, Yasuo; Watanabe, Ichiro

2011-01-01

Whether epicardial adipose tissue (EAT) is independently associated with atrial fibrillation (AF) and outcome after catheter ablation (CA) for AF remains unclear. Three-dimensional volume-rendering reconstructed images of EAT (total EAT) and EAT surrounding the left atrium (LA-EAT) were measured on 320-row multidetector computed tomography in 40 patients with AF (paroxysmal AF [PAF], n=24; persistent AF [PerAF], n=16) who underwent CA, and in 37 age-matched control patients. EAT volumes were as follows for the control, PAF and PerAF patients: total EAT, 138.3±45.2 cm 3 vs. 158.3±47.2 cm 3 vs. 226.4±93.3 cm 3 (P 3 vs. 41.3±15.3 cm 3 vs. 66.8±35.1 cm 3 (P 3 vs. 106.2±27.3 cm 3 , P=0.021; LA-EAT: 34.0±10.6 cm 3 vs. 21.8±6.9 cm 3 , P=0.0006). EAT volumes were greater in the 15 AF patients (37.5%) with post-ablation recurrence than in patients without recurrence (total EAT: 239.0±90.2 cm 3 vs. 153.5±42.7 cm 3 , P=0.0002; LA-EAT: 69.6±35.5 cm 3 vs. 40.7±13.9 cm 3 , P=0.0008). EAT volume increases in AF patients independent of conventional risk factors and is greater in patients with lone AF than in non-AF patients. EAT volume might be useful for predicting AF recurrence after CA. (author)

Dosimetric precision requirements and quantities for characterizing the response of tumors and normal tissues

Energy Technology Data Exchange (ETDEWEB)

Brahme, A [Karolinska Inst., Stockholm (Sweden). Dept. of Radiation Physics

1996-08-01

Based on simple radiobiological models the effect of the distribution of absorbed dose in therapy beams on the radiation response of tumor and normal tissue volumes are investigated. Under the assumption that the dose variation in the treated volume is small it is shown that the response of the tissue to radiation is determined mainly by the mean dose to the tumor or normal tissue volume in question. Quantitative expressions are also given for the increased probability of normal tissue complications and the decreased probability of tumor control as a function of increasing dose variations around the mean dose level to these tissues. When the dose variations are large the minimum tumor dose (to cm{sup 3} size volumes) will generally be better related to tumor control and the highest dose to significant portions of normal tissue correlates best to complications. In order not to lose more than one out of 20 curable patients (95% of highest possible treatment outcome) the required accuracy in the dose distribution delivered to the target volume should be 2.5% (1{sigma}) for a mean dose response gradient {gamma} in the range 2 - 3. For more steeply responding tumors and normal tissues even stricter requirements may be desirable. (author). 15 refs, 6 figs.

Effects of tissue mechanical properties on susceptibility to histotripsy-induced tissue damage

Science.gov (United States)

Vlaisavljevich, Eli; Kim, Yohan; Owens, Gabe; Roberts, William; Cain, Charles; Xu, Zhen

2014-01-01

Histotripsy is a non-invasive tissue ablation method capable of fractionating tissue by controlling acoustic cavitation. To determine the fractionation susceptibility of various tissues, we investigated histotripsy-induced damage on tissue phantoms and ex vivo tissues with different mechanical strengths. A histotripsy bubble cloud was formed at tissue phantom surfaces using 5-cycle long ultrasound pulses with peak negative pressure of 18 MPa and PRFs of 10, 100, and 1000 Hz. Results showed significantly smaller lesions were generated in tissue phantoms of higher mechanical strength. Histotripsy was also applied to 43 different ex vivo porcine tissues with a wide range of mechanical properties. Gross morphology demonstrated stronger tissues with higher ultimate stress, higher density, and lower water content were more resistant to histotripsy damage in comparison to weaker tissues. Based on these results, a self-limiting vessel-sparing treatment strategy was developed in an attempt to preserve major vessels while fractionating the surrounding target tissue. This strategy was tested in porcine liver in vivo. After treatment, major hepatic blood vessels and bile ducts remained intact within a completely fractionated liver volume. These results identify varying susceptibilities of tissues to histotripsy therapy and provide a rational basis to optimize histotripsy parameters for treatment of specific tissues.

Effects of Anti-VEGF on Predicted Antibody Biodistribution: Roles of Vascular Volume, Interstitial Volume, and Blood Flow

Science.gov (United States)

Boswell, C. Andrew; Ferl, Gregory Z.; Mundo, Eduardo E.; Bumbaca, Daniela; Schweiger, Michelle G.; Theil, Frank-Peter; Fielder, Paul J.; Khawli, Leslie A.

2011-01-01

Background The identification of clinically meaningful and predictive models of disposition kinetics for cancer therapeutics is an ongoing pursuit in drug development. In particular, the growing interest in preclinical evaluation of anti-angiogenic agents alone or in combination with other drugs requires a complete understanding of the associated physiological consequences. Methodology/Principal Findings Technescan™ PYP™, a clinically utilized radiopharmaceutical, was used to measure tissue vascular volumes in beige nude mice that were naïve or administered a single intravenous bolus dose of a murine anti-vascular endothelial growth factor (anti-VEGF) antibody (10 mg/kg) 24 h prior to assay. Anti-VEGF had no significant effect (p>0.05) on the fractional vascular volumes of any tissues studied; these findings were further supported by single photon emission computed tomographic imaging. In addition, apart from a borderline significant increase (p = 0.048) in mean hepatic blood flow, no significant anti-VEGF-induced differences were observed (p>0.05) in two additional physiological parameters, interstitial fluid volume and the organ blood flow rate, measured using indium-111-pentetate and rubidium-86 chloride, respectively. Areas under the concentration-time curves generated by a physiologically-based pharmacokinetic model changed substantially (>25%) in several tissues when model parameters describing compartmental volumes and blood flow rates were switched from literature to our experimentally derived values. However, negligible changes in predicted tissue exposure were observed when comparing simulations based on parameters measured in naïve versus anti-VEGF-administered mice. Conclusions/Significance These observations may foster an enhanced understanding of anti-VEGF effects in murine tissues and, in particular, may be useful in modeling antibody uptake alone or in combination with anti-VEGF. PMID:21436893

Serotonin transporter binding in the hypothalamus correlates negatively with tonic heat pain ratings in healthy subjects: A [11C]DASB PET study

DEFF Research Database (Denmark)

Kupers, Ron; Frokjaer, Vibe G.; Erritzoe, David

2010-01-01

There is a large body of evidence that the serotonergic system plays an important role in the transmission and regulation of pain. Here we used positron emission tomography (PET) with the serotonin transporter (SERT) tracer [11C]DASB to study the relationship between SERT binding in the brain and....... The negative correlation between SERT binding in the hypothalamus and insula with tonic pain ratings suggests a possible serotonergic control of the role of these areas in the modulation or in the affective appreciation of pain.......) tonic noxious heat stimulus. PET data were analyzed using both volume-of-interest (VOI) and voxel-based approaches. VOI analysis revealed a significant negative correlation between tonic pain ratings and SERT binding in the hypothalamus (r = −0.59; p = 0.008), a finding confirmed by the parametric...... analysis. The parametric analysis also revealed a negative correlation between tonic pain ratings and SERT binding in the right anterior insula. Measures of regional SERT binding did not correlate with pain threshold or with responses to short phasic suprathreshold phasic heat stimuli. Finally, the VOI...

Prognostic value of defining the systemic tumor volume with FDG-PET in diffuse large b cell lymphoma

International Nuclear Information System (INIS)

Byun, Byung Hyun; Lim, Sang Moo; Cheon, Gi Jeong; Choi, Chang Woon; Kang, Hye Jin; Na, Im Il; Ryoo, Baek Yeol; Yang, Sung Hyun

2007-01-01

We measured the systemic tumor volume using FDG-PET in patients with diffuse large B cell lymphoma (DLBL). We also investigated its prognostic role, and compared it with that of other prognostic factors. FDG PET was performed in 38 newly diagnosed DLBL patients (20 men, 18 women, age 55.715.1 years) at pre-treatment of chemotherapy. Clinical staging of lymphoma was evaluated by Ann Arbor system. On each FDG PET scan, we acquired volume of interest (VOl) at the cut-off value of SUV=2.5 in every measurable tumor by the automatic edge detection software. According to the VOI, we measured the metabolic volume and mean SUV, and estimated volume-activity indexes (SUV Vol) as mean SUV times metabolic volume. And then, we calculated the summed metabolic volume (VOLsum) and summed SUV Vol (SUV Volsum) in every FDG PET scan. Maximum SUV of involved lesion (SUVmax) was also acquired on each FDG PET scan. Time to treatment failure (TTF) was compared among VOLsum (median), SUV Volsum (median), SUVmax (median), clinical stage, gender, age, LDH, and performance status-assigned response designations by Kaplan-Meier survival analysis. Initial stages of DLBL patients were stage I in 4, II in 14, III in 15, and IV in 4 by Ann Arbor system. Median follow up period was 15.5months, and estimated mean TTF was 22.3 months. Univariate analysis demonstrated that TTF is statistically significantly reduced in those with high VOLsum (>215.1cm2, p=0.004), high SUV Volsum (>1577.5, p=0.003), and increased LDH (p=0.036). TTF did not correlate with SUVmax (p=0.571), clinical stage (p=0.194), gender (p=0.549), and age (p=0.128), and performance status =2 (p=0.074). Multivariate analysis using VOLsum, SUV Volsum, LDH, and performance status demonstrated no statistically significant predictor of TTF (p>0.05). Systemic tumor volume measurement using FDG-PET is suggestive to be the significant prognostic factor in patients with DLBL

Alveolar Ridge Contouring with Free Connective Tissue Graft at Implant Placement: A 5-Year Consecutive Clinical Study.

Science.gov (United States)

Hanser, Thomas; Khoury, Fouad

2016-01-01

This study evaluated volume stability after alveolar ridge contouring with free connective tissue grafts at implant placement in single-tooth gaps. A total of 52 single-tooth gaps with labial volume deficiencies in the maxilla (incisors, canines, and premolars) were consecutively treated with implants and concomitant free palatal connective tissue grafts in 46 patients between 2006 and 2009. Implants had to be covered with at least 2 mm peri-implant local bone after insertion. At implant placement, a free connective tissue graft from the palate was fixed inside a labial split-thickness flap to form an existing concave buccal alveolar ridge contour due to tissue volume deficiency into a convex shape. Standardized volumetric measurements of the labial alveolar contour using a template were evaluated before connective tissue grafting and at 2 weeks, 1 year, and 5 years after implantprosthetic incorporation. Tissue volume had increased significantly (P tissue contour of the implant before connective tissue grafting to baseline (2 weeks after implant-prosthetic incorporation). Statistically, 50% of the reference points (P > .05) kept their volume from baseline to 1 year after prosthetic incorporation and from baseline to 5 years after prosthetic incorporation, respectively, whereas reference points located within the area of the implant sulcus showed a significant (P connective tissue grafting appears to be an appropriate long-term means to contour preexisting buccal alveolar volume deficiencies in single implants.

Adipose tissue engineering: state of the art, recent advances and innovative approaches.

Science.gov (United States)

Tanzi, Maria Cristina; Farè, Silvia

2009-09-01

Adipose tissue is a highly specialized connective tissue found either in white or brown forms, the white form being the most abundant in adult humans. Loss or damage of white adipose tissue due to aging or pathological conditions needs reconstructive approaches. To date, two main strategies are being investigated for generating functional adipose tissue: autologous tissue/cell transplantation and adipose tissue engineering. Free-fat transplantation rarely achieves sufficient tissue augmentation owing to delayed neovascularization, with subsequent cell necrosis and graft volume shrinkage. Tissue engineering approaches represent, instead, a more suitable alternative for adipose tissue regeneration; they can be performed either with in situ or de novo adipogenesis. In situ adipogenesis or transplantation of encapsulated cells can be useful in healing small-volume defects, whereas restoration of large defects, where vascularization and a rapid volumetric gain are strict requirements, needs de novo strategies with 3D scaffold/filling matrix combinations. For adipose tissue engineering, the use of adult mesenchymal stem cells (both adipose- and bone marrow-derived stem cells) or of preadipocytes is preferred to the use of mature adipocytes, which have low expandability and poor ability for volume retention. This review intends to assemble and describe recent work on this topic, critically presenting successes obtained and drawbacks faced to date.

Soft Tissue Biomechanical Modeling for Computer Assisted Surgery

CERN Document Server

2012-01-01

  This volume focuses on the biomechanical modeling of biological tissues in the context of Computer Assisted Surgery (CAS). More specifically, deformable soft tissues are addressed since they are the subject of the most recent developments in this field. The pioneering works on this CAS topic date from the 1980's, with applications in orthopaedics and biomechanical models of bones. More recently, however, biomechanical models of soft tissues have been proposed since most of the human body is made of soft organs that can be deformed by the surgical gesture. Such models are much more complicated to handle since the tissues can be subject to large deformations (non-linear geometrical framework) as well as complex stress/strain relationships (non-linear mechanical framework). Part 1 of the volume presents biomechanical models that have been developed in a CAS context and used during surgery. This is particularly new since most of the soft tissues models already proposed concern Computer Assisted Planning, with ...

Effect of hGC-MSCs from human gastric cancer tissue on cell proliferation, invasion and epithelial-mesenchymal transition in tumor tissue of gastric cancer tumor-bearing mice.

Science.gov (United States)

Song, Lin; Zhou, Xin; Jia, Hong-Jun; Du, Mei; Zhang, Jin-Ling; Li, Liang

2016-08-01

To study the effect of hGC-MSCs from human gastric cancer tissue on cell proliferation, invasion and epithelial-mesenchymal transition in tumor tissue of gastric cancer tumor-bearing mice. BABL/c nude mice were selected as experimental animals and gastric cancer tumor-bearing mice model were established by subcutaneous injection of gastric cancer cells, randomly divided into different intervention groups. hGC-MSCs group were given different amounts of gastric cancer cells for subcutaneous injection, PBS group was given equal volume of PBS for subcutaneous injection. Then tumor tissue volume were determined, tumor-bearing mice were killed and tumor tissues were collected, mRNA expression of proliferation, invasion, EMT-related molecules were determined. 4, 8, 12, 16, 20 d after intervention, tumor tissue volume of hGC-MSCs group were significantly higher than those of PBS group and the more the number of hGC-MSCs, the higher the tumor tissue volume; mRNA contents of Ki-67, PCNA, Bcl-2, MMP-2, MMP-7, MMP-9, MMP-14, N-cadherin, vimentin, Snail and Twist in tumor tissue of hGC-MSCs group were higher than those of PBS group, and mRNA contents of Bax, TIMP1, TIMP2 and E-cadherin were lower than those of PBS group. hGC-MSCs from human gastric cancer tissue can promote the tumor growth in gastric cancer tumor-bearing mice, and the molecular mechanism includes promoting cell proliferation, invasion and epithelial-mesenchymal transition. Copyright © 2016 Hainan Medical College. Production and hosting by Elsevier B.V. All rights reserved.

Non-uniform versus uniform attenuation correction in brain perfusion SPET of healthy volunteers

International Nuclear Information System (INIS)

Van Laere, K.; Versijpt, J.; Dierckx, R.; Koole, M.

2001-01-01

Although non-uniform attenuation correction (NUAC) can supply more accurate absolute quantification, it is not entirely clear whether NUAC provides clear-cut benefits in the routine clinical practice of brain SPET imaging. The aim of this study was to compare the effect of NUAC versus uniform attenuation correction (UAC) on volume of interest (VOI)-based semi-quantification of a large age- and gender-stratified brain perfusion normal database. Eighty-nine healthy volunteers (46 females and 43 males, aged 20-81 years) underwent standardised high-resolution single-photon emission tomography (SPET) with 925 MBq 99m Tc-ethyl cysteinate dimer (ECD) on a Toshiba GCA-9300A camera with 153 Gd or 99m Tc transmission CT scanning. Emission images were reconstructed by filtered back-projection and scatter corrected using the triple-energy window correction method. Both non-uniform Chang attenuation correction (one iteration) and uniform Sorenson correction (attenuation coefficient 0.09 cm -1 ) were applied. Images were automatically re-oriented to a stereotactic template on which 35 predefined VOIs were defined for semi-quantification (normalisation on total VOI counts). Small but significant differences between relative VOI uptake values for NUAC versus UAC in the infratentorial region were found. VOI standard deviations were significantly smaller for UAC, 4.5% (range 2.6-7.5), than for NUAC, 5.0% (2.3-9.0) (P 99m Tc-ECD uptake values in healthy volunteers to those obtained with NUAC, although values for the infratentorial region are slightly lower. NUAC produces a slight increase in inter-subject variability. Further study is necessary in various patient populations to establish the full clinical impact of NUAC in brain perfusion SPET. (orig.)

Effect of the averaging volume and algorithm on the in situ electric field for uniform electric- and magnetic-field exposures

International Nuclear Information System (INIS)

Hirata, Akimasa; Takano, Yukinori; Fujiwara, Osamu; Kamimura, Yoshitsugu

2010-01-01

The present study quantified the volume-averaged in situ electric field in nerve tissues of anatomically based numeric Japanese male and female models for exposure to extremely low-frequency electric and magnetic fields. A quasi-static finite-difference time-domain method was applied to analyze this problem. The motivation of our investigation is that the dependence of the electric field induced in nerve tissue on the averaging volume/distance is not clear, while a cubical volume of 5 x 5 x 5 mm 3 or a straight-line segment of 5 mm is suggested in some documents. The influence of non-nerve tissue surrounding nerve tissue is also discussed by considering three algorithms for calculating the averaged in situ electric field in nerve tissue. The computational results obtained herein reveal that the volume-averaged electric field in the nerve tissue decreases with the averaging volume. In addition, the 99th percentile value of the volume-averaged in situ electric field in nerve tissue is more stable than that of the maximal value for different averaging volume. When including non-nerve tissue surrounding nerve tissue in the averaging volume, the resultant in situ electric fields were not so dependent on the averaging volume as compared to the case excluding non-nerve tissue. In situ electric fields averaged over a distance of 5 mm were comparable or larger than that for a 5 x 5 x 5 mm 3 cube depending on the algorithm, nerve tissue considered and exposure scenarios. (note)

MR-guided noninvasive thermal coagulation of in-vivo liver tissue using ultrasonic phased array

Science.gov (United States)

Daum, Douglas R.; Smith, Nadine; McDannold, Nathan; Hynynen, Kullervo H.

1999-05-01

Magnetic resonance (MR) imaging was used to guide and monitor the thermal tissue coagulation of in vivo porcine tissue using a 256 element ultrasonic phased array. The array could coagulate tissue volumes greater than 2 cm3 in liver and 0.5 cm3 in kidney using a single 20 second sonication. This sonication used multiple focus fields which were temporally cycled to heat large tissue volumes simultaneously. Estimates of the coagulated tissue using a thermal dose threshold compare well with T2-weighted images of post sonication lesions. The overlapping large focal volumes could aid in the treatment of large tumor volumes which require multiple overlapping sonications. The ability of MR to detect the presence and undesirable thermal increases at acoustic obstacle such as cartilaginous and bony ribs is demonstrated. This could have a significant impact on the ability to monitor thermal treatments of the liver and other organs which are acoustically blocked.

Brain regional α-[11C]methyl-L-tryptophan trapping, used as an index of 5-HT synthesis, in healthy adults: absence of an age effect

International Nuclear Information System (INIS)

Rosa-Neto, Pedro; Benkelfat, Chawki; Leyton, Marco; Sakai, Yojiro; Morais, Jose A.; Diksic, Mirko

2007-01-01

Previous functional neuroimaging studies suggest that selective aspects of the brain serotonin (5-HT) system change during the aging process. Here, we assessed the effects of aging on the brain regional α-[ 11 C]methyl-L-tryptophan (α-[ 11 C]MTrp) trapping rate constant (K*; μl.g -1 .min -1 ), which, with certain assumptions, could be taken as a proxy of 5-HT synthesis. Thirty-six healthy right-handed subjects had positron emission tomography (PET) scans following injection with α-[ 11 C]MTrp [18 males aged 46.6 ± 22.2 years (range 20-80 years) and 18 females aged 33.0 ± 15.5 years (range 20-80 years)]. The trapping rate constant, K*, was calculated with the graphical method for irreversible ligands using the sinus-venous input function. A priori selected volumes of interest (VOIs) were defined using an automatic algorithm. VOI analysis showed no correlation between age and brain regional K* values. As reported by others, significant age-related reductions of gray matter were observed in the thalamus and frontal and cingulate cortices; even with partial volume correction there was still no significant relationship between K* and age. Further exploratory SPM voxelwise correlation between age and α-[ 11 C]MTrp trapping, using p = 0.05 (uncorrected), as well as voxel-based morphometry, was in agreement with the VOI analysis. The dissociation between age-related changes in brain anatomy and this index of serotonin synthesis suggests independent mechanisms underlying the normal aging process. (orig.)

Clinical evaluation of respiration-induced attenuation uncertainties in pulmonary 3D PET/CT.

Science.gov (United States)

Kruis, Matthijs F; van de Kamer, Jeroen B; Vogel, Wouter V; Belderbos, José Sa; Sonke, Jan-Jakob; van Herk, Marcel

2015-12-01

In contemporary positron emission tomography (PET)/computed tomography (CT) scanners, PET attenuation correction is performed by means of a CT-based attenuation map. Respiratory motion can however induce offsets between the PET and CT data. Studies have demonstrated that these offsets can cause errors in quantitative PET measures. The purpose of this study is to quantify the effects of respiration-induced CT differences on the attenuation correction of pulmonary 18-fluordeoxyglucose (FDG) 3D PET/CT in a patient population and to investigate contributing factors. For 32 lung cancer patients, 3D-CT, 4D-PET and 4D-CT data were acquired. The 4D FDG PET data were attenuation corrected (AC) using a free-breathing 3D-CT (3D-AC), the end-inspiration CT (EI-AC), the end-expiration CT (EE-AC) or phase-by-phase (P-AC). After reconstruction and AC, the 4D-PET data were averaged. In the 4Davg data, we measured maximum tumour standardised uptake value (SUV)max in the tumour, SUVmean in a lung volume of interest (VOI) and average SUV (SUVmean) in a muscle VOI. On the 4D-CT, we measured the lung volume differences and CT number changes between inhale and exhale in the lung VOI. Compared to P-AC, we found -2.3% (range -9.7% to 1.2%) lower tumour SUVmax in EI-AC and 2.0% (range -0.9% to 9.5%) higher SUVmax in EE-AC. No differences in the muscle SUV were found. The use of 3D-AC led to respiration-induced SUVmax differences up to 20% compared to the use of P-AC. SUVmean differences in the lung VOI between EI-AC and EE-AC correlated to average CT differences in this region (ρ = 0.83). SUVmax differences in the tumour correlated to the volume changes of the lungs (ρ = -0.55) and the motion amplitude of the tumour (ρ = 0.53), both as measured on the 4D-CT. Respiration-induced CT variations in clinical data can in extreme cases lead to SUV effects larger than 10% on PET attenuation correction. These differences were case specific and correlated to differences in CT number

Advances and perspectives in tissue clearing using CLARITY

DEFF Research Database (Denmark)

Reveles Jensen, Kristian; Berg, Rune W.

2017-01-01

CLARITY is a tissue clearing method, which enables immunostaining and imaging of large volumes for 3D-reconstruction. The method was initially time-consuming, expensive and relied on electrophoresis to remove lipids to make the tissue transparent. Since then several improvements and simplifications...

Correction volumes and densities in Vitrea Program

International Nuclear Information System (INIS)

Abrantes, Marcos E.S.; Oliveira, A.H. de

2014-01-01

Introduction: with the increased use of 3D reconstruction techniques to assist in diagnosis, Vitrea® program is widely used. To use this program you need to know the correction values to generate the volumes and number of real CT human tissues. Objective: provide correction values for volumes and number of CT, read the Vitrea program, of the tissues generated by DICOM images from CT. Methodology: this study used a PMMA chest phantom to generate the DICOM images on a scanner. To check the calibration of the scanner was used Catphan phantom and compared the manufacturer of the values associated with its straight linearity. Results: the volume of PMMA phantom was of 11166.58 cm³ and CT number (123.5 ± 33.4) UH. For the volume found in Vitrea program, according to the structures of interest, were 11897.29 cm 3 , 10901.65 cm³, 16906.49 cm 3 and 11848.34 cm³ and corrections values are -6.14%, + 2.43% -6.94% -5.75% respectively for the tissues: lung, bone, soft and full. For the CT numbers found in this program were (97.60 ± 58.9) UH, (72.00 ± 176.00) UH, (143.20 ± 19.50) UH and (31.90 ± 239,10) UH and corrections of + 26.54%, + 71.53%, -13.64% and 387.15% respectively for tissues: lung, bone, soft and full. Conclusion: the procedure performed can be used in other 3D reconstruction programs and where there are tools to reading CT number, observing the necessary corrections

Role of percent peripheral tissue ablated on refractive outcomes following hyperopic LASIK

Science.gov (United States)

Stapleton, Fiona; Versace, Patrick

2017-01-01

Objectives To determine the effect of hyperopic laser in situ keratomileusis (H-LASIK) on corneal integrity, by investigating relationships between proportionate corneal tissue ablated and refractive outcomes at 3 months. Methods 18 eyes of 18 subjects treated with H-LASIK by Technolas 217c Excimer Laser were included in the study. Orbscan II Topography System was used to determine corneal volume and pachymetry 3mm temporally (3T). The volume of corneal tissue ablated was determined from the laser nomogram. Univariate associations between age, treatment, corneal volume, overall proportion of tissue removed, proportion of tissue removed at 3T, residual bed thickness at 3T and refractive outcomes 3 months post-LASIK were examined and independent factors associated with refractive outcomes determined using linear regression models. Results At 3 months post-LASIK, the mean difference to expected refractive outcome was -0.20 ± 0.64 (Range -2.00 to +1.00). In univariate analysis, difference to expected refractive outcome was associated with proportion of tissue removed at 3T (PLASIK, may present as either over or under-corrected at 3 months. The proportion of tissue removed at 3T was the single significant determinant of this outcome, suggesting unexpected biomechanical alterations resulting in corneal steepening. Future hyperopic LASIK procedures could consider proportionate volume of corneal tissue removed at 3T in addition to laser nomograms to achieve improved refractive outcomes. PMID:28151939

Photoactivated Composite Biomaterial for Soft Tissue Restoration in Rodents and in Humans

Science.gov (United States)

Nahas, Zayna; Reid, Branden; Coburn, Jeannine M.; Axelman, Joyce; Chae, Jemin J.; Guo, Qiongyu; Trow, Robert; Thomas, Andrew; Hou, Zhipeng; Lichtsteiner, Serge; Sutton, Damon; Matheson, Christine; Walker, Patricia; David, Nathaniel; Mori, Susumu; Taube, Janis M.; Elisseeff, Jennifer H.

2015-01-01

Soft tissue reconstruction often requires multiple surgical procedures that can result in scars and disfiguration. Facial soft tissue reconstruction represents a clinical challenge because even subtle deformities can severely affect an individual’s social and psychological function. We therefore developed a biosynthetic soft tissue replacement composed of poly(ethylene glycol) (PEG) and hyaluronic acid (HA) that can be injected and photocrosslinked in situ with transdermal light exposure. Modulating the ratio of synthetic to biological polymer allowed us to tune implant elasticity and volume persistence. In a small-animal model, implanted photocrosslinked PEG-HA showed a dose-dependent relationship between increasing PEG concentration and enhanced implant volume persistence. In direct comparison with commercial HA injections, the PEG-HA implants maintained significantly greater average volumes and heights. Reversibility of the implant volume was achieved with hyaluronidase injection. Pilot clinical testing in human patients confirmed the feasibility of the transdermal photocrosslinking approach for implantation in abdomen soft tissue, although an inflammatory response was observed surrounding some of the materials. PMID:21795587

A biphasic model for bleeding in soft tissue

Science.gov (United States)

Chang, Yi-Jui; Chong, Kwitae; Eldredge, Jeff D.; Teran, Joseph; Benharash, Peyman; Dutson, Erik

2017-11-01

The modeling of blood passing through soft tissues in the body is important for medical applications. The current study aims to capture the effect of tissue swelling and the transport of blood under bleeding or hemorrhaging conditions. The soft tissue is considered as a non-static poro-hyperelastic material with liquid-filled voids. A biphasic formulation effectively, a generalization of Darcy's law-is utilized, treating the phases as occupying fractions of the same volume. The interaction between phases is captured through a Stokes-like friction force on their relative velocities and a pressure that penalizes deviations from volume fractions summing to unity. The soft tissue is modeled as a hyperelastic material with a typical J-shaped stress-strain curve, while blood is considered as a Newtonian fluid. The method of Smoothed Particle Hydrodynamics is used to discretize the conservation equations based on the ease of treating free surfaces in the liquid. Simulations of swelling under acute hemorrhage and of draining under gravity and compression will be demonstrated. Ongoing progress in modeling of organ tissues under injuries and surgical conditions will be discussed.

Dose Distribution in Bladder and Surrounding Normal Tissues in Relation to Bladder Volume in Conformal Radiotherapy for Bladder Cancer

International Nuclear Information System (INIS)

Majewski, Wojciech; Wesolowska, Iwona; Urbanczyk, Hubert; Hawrylewicz, Leszek; Schwierczok, Barbara; Miszczyk, Leszek

2009-01-01

Purpose: To estimate bladder movements and changes in dose distribution in the bladder and surrounding tissues associated with changes in bladder filling and to estimate the internal treatment margins. Methods and Materials: A total of 16 patients with bladder cancer underwent planning computed tomography scans with 80- and 150-mL bladder volumes. The bladder displacements associated with the change in volume were measured. Each patient had treatment plans constructed for a 'partially empty' (80 mL) and a 'partially full' (150 mL) bladder. An additional plan was constructed for tumor irradiation alone. A subsequent 9 patients underwent sequential weekly computed tomography scanning during radiotherapy to verify the bladder movements and estimate the internal margins. Results: Bladder movements were mainly observed cranially, and the estimated internal margins were nonuniform and largest (>2 cm) anteriorly and cranially. The dose distribution in the bladder worsened if the bladder increased in volume: 70% of patients (11 of 16) would have had bladder underdosed to 70%, 80%, and 90% of the prescribed dose was 23%, 20%, and 15% for the rectum and 162, 144, 123 cm 3 for the intestines, respectively) than with a 'partially full' bladder (volume that received >70%, 80%, and 90% of the prescribed dose was 28%, 24%, and 18% for the rectum and 180, 158, 136 cm 3 for the intestines, respectively). The change in bladder filling during RT was significant for the dose distribution in the intestines. Tumor irradiation alone was significantly better than whole bladder irradiation in terms of organ sparing. Conclusion: The displacements of the bladder due to volume changes were mainly related to the upper wall. The internal margins should be nonuniform, with the largest margins cranially and anteriorly. The changes in bladder filling during RT could influence the dose distribution in the bladder and intestines. The dose distribution in the rectum and bowel was slightly better with

Computational Modeling in Tissue Engineering

CERN Document Server

2013-01-01

One of the major challenges in tissue engineering is the translation of biological knowledge on complex cell and tissue behavior into a predictive and robust engineering process. Mastering this complexity is an essential step towards clinical applications of tissue engineering. This volume discusses computational modeling tools that allow studying the biological complexity in a more quantitative way. More specifically, computational tools can help in:  (i) quantifying and optimizing the tissue engineering product, e.g. by adapting scaffold design to optimize micro-environmental signals or by adapting selection criteria to improve homogeneity of the selected cell population; (ii) quantifying and optimizing the tissue engineering process, e.g. by adapting bioreactor design to improve quality and quantity of the final product; and (iii) assessing the influence of the in vivo environment on the behavior of the tissue engineering product, e.g. by investigating vascular ingrowth. The book presents examples of each...

A method to estimate the fractional fat volume within a ROI of a breast biopsy for WAXS applications: Animal tissue evaluation

International Nuclear Information System (INIS)

Tang, Robert Y.; McDonald, Nancy; Laamanen, Curtis; LeClair, Robert J.

2014-01-01

Purpose: To develop a method to estimate the mean fractional volume of fat (ν ¯ fat ) within a region of interest (ROI) of a tissue sample for wide-angle x-ray scatter (WAXS) applications. A scatter signal from the ROI was obtained and use of ν ¯ fat in a WAXS fat subtraction model provided a way to estimate the differential linear scattering coefficient μ s of the remaining fatless tissue. Methods: The efficacy of the method was tested using animal tissue from a local butcher shop. Formalin fixed samples, 5 mm in diameter 4 mm thick, were prepared. The two main tissue types were fat and meat (fibrous). Pure as well as composite samples consisting of a mixture of the two tissue types were analyzed. For the latter samples, ν fat for the tissue columns of interest were extracted from corresponding pixels in CCD digital x-ray images using a calibration curve. The means ν ¯ fat were then calculated for use in a WAXS fat subtraction model. For the WAXS measurements, the samples were interrogated with a 2.7 mm diameter 50 kV beam and the 6° scattered photons were detected with a CdTe detector subtending a solid angle of 7.75 × 10 −5 sr. Using the scatter spectrum, an estimate of the incident spectrum, and a scatter model, μ s was determined for the tissue in the ROI. For the composite samples, a WAXS fat subtraction model was used to estimate the μ s of the fibrous tissue in the ROI. This signal was compared to μ s of fibrous tissue obtained using a pure fibrous sample. Results: For chicken and beef composites, ν ¯ fat =0.33±0.05 and 0.32 ± 0.05, respectively. The subtractions of these fat components from the WAXS composite signals provided estimates of μ s for chicken and beef fibrous tissue. The differences between the estimates and μ s of fibrous obtained with a pure sample were calculated as a function of the momentum transfer x. A t-test showed that the mean of the differences did not vary from zero in a statistically significant way thereby

Force estimation from OCT volumes using 3D CNNs.

Science.gov (United States)

Gessert, Nils; Beringhoff, Jens; Otte, Christoph; Schlaefer, Alexander

2018-05-04

Estimating the interaction forces of instruments and tissue is of interest, particularly to provide haptic feedback during robot-assisted minimally invasive interventions. Different approaches based on external and integrated force sensors have been proposed. These are hampered by friction, sensor size, and sterilizability. We investigate a novel approach to estimate the force vector directly from optical coherence tomography image volumes. We introduce a novel Siamese 3D CNN architecture. The network takes an undeformed reference volume and a deformed sample volume as an input and outputs the three components of the force vector. We employ a deep residual architecture with bottlenecks for increased efficiency. We compare the Siamese approach to methods using difference volumes and two-dimensional projections. Data were generated using a robotic setup to obtain ground-truth force vectors for silicon tissue phantoms as well as porcine tissue. Our method achieves a mean average error of [Formula: see text] when estimating the force vector. Our novel Siamese 3D CNN architecture outperforms single-path methods that achieve a mean average error of [Formula: see text]. Moreover, the use of volume data leads to significantly higher performance compared to processing only surface information which achieves a mean average error of [Formula: see text]. Based on the tissue dataset, our methods shows good generalization in between different subjects. We propose a novel image-based force estimation method using optical coherence tomography. We illustrate that capturing the deformation of subsurface structures substantially improves force estimation. Our approach can provide accurate force estimates in surgical setups when using intraoperative optical coherence tomography.

Automatic anatomy partitioning of the torso region on CT images by using multiple organ localizations with a group-wise calibration technique

Science.gov (United States)

Zhou, Xiangrong; Morita, Syoichi; Zhou, Xinxin; Chen, Huayue; Hara, Takeshi; Yokoyama, Ryujiro; Kanematsu, Masayuki; Hoshi, Hiroaki; Fujita, Hiroshi

2015-03-01

This paper describes an automatic approach for anatomy partitioning on three-dimensional (3D) computedtomography (CT) images that divide the human torso into several volume-of-interesting (VOI) images based on anatomical definition. The proposed approach combines several individual detections of organ-location with a groupwise organ-location calibration and correction to achieve an automatic and robust multiple-organ localization task. The essence of the proposed method is to jointly detect the 3D minimum bounding box for each type of organ shown on CT images based on intra-organ-image-textures and inter-organ-spatial-relationship in the anatomy. Machine-learning-based template matching and generalized Hough transform-based point-distribution estimation are used in the detection and calibration processes. We apply this approach to the automatic partitioning of a torso region on CT images, which are divided into 35 VOIs presenting major organ regions and tissues required by routine diagnosis in clinical medicine. A database containing 4,300 patient cases of high-resolution 3D torso CT images is used for training and performance evaluations. We confirmed that the proposed method was successful in target organ localization on more than 95% of CT cases. Only two organs (gallbladder and pancreas) showed a lower success rate: 71 and 78% respectively. In addition, we applied this approach to another database that included 287 patient cases of whole-body CT images scanned for positron emission tomography (PET) studies and used for additional performance evaluation. The experimental results showed that no significant difference between the anatomy partitioning results from those two databases except regarding the spleen. All experimental results showed that the proposed approach was efficient and useful in accomplishing localization tasks for major organs and tissues on CT images scanned using different protocols.

Evidence that breast tissue stiffness is associated with risk of breast cancer.

Science.gov (United States)

Boyd, Norman F; Li, Qing; Melnichouk, Olga; Huszti, Ella; Martin, Lisa J; Gunasekara, Anoma; Mawdsley, Gord; Yaffe, Martin J; Minkin, Salomon

2014-01-01

Evidence from animal models shows that tissue stiffness increases the invasion and progression of cancers, including mammary cancer. We here use measurements of the volume and the projected area of the compressed breast during mammography to derive estimates of breast tissue stiffness and examine the relationship of stiffness to risk of breast cancer. Mammograms were used to measure the volume and projected areas of total and radiologically dense breast tissue in the unaffected breasts of 362 women with newly diagnosed breast cancer (cases) and 656 women of the same age who did not have breast cancer (controls). Measures of breast tissue volume and the projected area of the compressed breast during mammography were used to calculate the deformation of the breast during compression and, with the recorded compression force, to estimate the stiffness of breast tissue. Stiffness was compared in cases and controls, and associations with breast cancer risk examined after adjustment for other risk factors. After adjustment for percent mammographic density by area measurements, and other risk factors, our estimate of breast tissue stiffness was significantly associated with breast cancer (odds ratio = 1.21, 95% confidence interval = 1.03, 1.43, p = 0.02) and improved breast cancer risk prediction in models with percent mammographic density, by both area and volume measurements. An estimate of breast tissue stiffness was associated with breast cancer risk and improved risk prediction based on mammographic measures and other risk factors. Stiffness may provide an additional mechanism by which breast tissue composition is associated with risk of breast cancer and merits examination using more direct methods of measurement.

Validation of 18FDG biodistribution data in healthy mice obtained with G.E. LABPET4

International Nuclear Information System (INIS)

Rocha, Adriana Marcia Guimaraes; Mendes, Bruno Melo; Malamut, Carlos; Silva, Juliana Batista da; Campos, Danielle Cunha; Santos, Priscilla Figueiredo

2013-01-01

The aim of this study is to validate biodistribution data obtained with CDTN's MicroPET. To achieve this goal, correction and image acquisition procedures were established. 1 '8FDG dynamic images of 90 minutes were obtained following these procedures for Swiss healthy mice. Biodistribution data obtained after quantification of acquired images were compared with data available in literature. Considering the uptake time of 60 minutes and similar animal handling, data obtained in this work showed a satisfactory agreement with reference data. Some evaluated organs/tissues showed high interindividual variability. These findings are consistent with those observed in reference literature. However, improvements in VOI positioning VOI technique as well as increasing the number of animals (n) per group can minimize this problem. (author)

Gender disparities in the association between epicardial adipose tissue volume and coronary atherosclerosis: A 3-dimensional cardiac computed tomography imaging study in Japanese subjects

OpenAIRE

Dagvasumberel Munkhbaatar; Shimabukuro Michio; Nishiuchi Takeshi; Ueno Junji; Takao Shoichiro; Fukuda Daiju; Hirata Yoichiro; Kurobe Hirotsugu; Soeki Takeshi; Iwase Takashi; Kusunose Kenya; Niki Toshiyuki; Yamaguchi Koji; Taketani Yoshio; Yagi Shusuke

2012-01-01

Abstract Background Growing evidence suggests that epicardial adipose tissue (EAT) may contribute to the development of coronary artery disease (CAD). In this study, we explored gender disparities in EAT volume (EATV) and its impact on coronary atherosclerosis. Methods The study population consisted of 90 consecutive subjects (age: 63 ± 12 years; men: 47, women: 43) who underwent 256-slice multi-detector computed tomography (MDCT) coronary angiography. EATV was measured as the sum of cross-se...

Gender-linked impact of epicardial adipose tissue volume in patients who underwent coronary artery bypass graft surgery or non-coronary valve surgery.

Science.gov (United States)

Maimaituxun, Gulinu; Shimabukuro, Michio; Salim, Hotimah Masdan; Tabata, Minoru; Yuji, Daisuke; Morimoto, Yoshihisa; Akasaka, Takeshi; Matsuura, Tomomi; Yagi, Shusuke; Fukuda, Daiju; Yamada, Hirotsugu; Soeki, Takeshi; Sugimoto, Takaki; Tanaka, Masashi; Takanashi, Shuichiro; Sata, Masataka

2017-01-01

Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD) are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV) in patients undergoing coronary artery bypass grafting (CABG) remains unknown. Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57) who underwent CABG or non-coronary valvular surgery (non-CABG). In men, EATV, EATV index (EATV/body surface area) and the markers of adiposity such as body mass index, waist circumference and visceral fat area were higher in the CABG group than in the non-CABG group. Traditional ASCVD risk factors were also prevalent in the CABG group. In women, EATV and EATV index were higher in the CABG group, but other adiposity markers were comparable between CABG and non-CABG groups. Multivariate logistic regression analysis showed that in men, CABG was determined by EATV Index and other ASCVD risk factors including hypertension, dyslipidemia, adiponectin, high sensitive C-reactive protein (hsCRP) and type 2 diabetes mellitus (Corrected R2 = 0.262, p EATV Index (Corrected R2 = 0.266, p = 0.005). Our study found that multiple risk factors, including epicardial adipose tissue volume and traditional ASCVD factors are determinants for CABG in men, but type 2 diabetes mellitus was the sole determinant in women. Gender-specific disparities in risk factors of CABG prompt us to evaluate new diagnostic and treatment strategies and to seek underlying mechanisms.

Short-term myeloid growth factor mediated expansion of bone marrow haemopoiesis studied by localized magnetic resonance proton spectroscopy

DEFF Research Database (Denmark)

Jensen, K E; Hansen, P B; Larsen, V A

1994-01-01

(day 0), day 5 and day 12. Spectroscopic examinations were performed with the stimulated echo acquisition mode (STEAM) method on a 1.5 T clinical whole-body imaging unit. A cubic volume of interest (VOI) was selected in the bone marrow of the left iliac bone. The patients responded with a rise in blood...

Adipose tissue in muscle: a novel depot similar in size to visceral adipose tissue

NARCIS (Netherlands)

Gallagher, D.; Kuznia, P.; Heshka, S.; Albu, J.; Heymsfield, S.B.; Goodpaster, B.H.; Visser, M.; Harris, T.B.

2005-01-01

BACKGROUND: The manner in which fat depot volumes and distributions, particularly the adipose tissue (AT) between the muscles, vary by race is unknown. OBJECTIVE: The objective was to quantify a previously unstudied and novel intermuscular AT (IMAT) depot and subcutaneous AT, visceral AT (VAT), and

Quantifying cerebral hypoxia by near-infrared spectroscopy tissue oximetry

DEFF Research Database (Denmark)

Rasmussen, Martin B.; Eriksen, Vibeke R.; Andresen, Bjørn

2017-01-01

Tissue oxygenation estimated by near-infrared spectroscopy (NIRS) is a volume-weighted mean of the arterial and venous hemoglobin oxygenation. In vivo validation assumes a fixed arterial-to-venous volume-ratio (AV-ratio). Regulatory cerebro-vascular mechanisms may change the AV-ratio. We used...

Options and pitfalls of normal tissues complication probability models

International Nuclear Information System (INIS)

Dorr, Wolfgang

2011-01-01

Full text: Technological improvements in the physical administration of radiotherapy have led to increasing conformation of the treatment volume (TV) with the planning target volume (PTV) and of the irradiated volume (IV) with the TV. In this process of improvement of the physical quality of radiotherapy, the total volumes of organs at risk exposed to significant doses have significantly decreased, resulting in increased inhomogeneities in the dose distributions within these organs. This has resulted in a need to identify and quantify volume effects in different normal tissues. Today, irradiated volume today must be considered a 6t h 'R' of radiotherapy, in addition to the 5 'Rs' defined by Withers and Steel in the mid/end 1980 s. The current status of knowledge of these volume effects has recently been summarized for many organs and tissues by the QUANTEC (Quantitative Analysis of Normal Tissue Effects in the Clinic) initiative [Int. J. Radiat. Oncol. BioI. Phys. 76 (3) Suppl., 2010]. However, the concept of using dose-volume histogram parameters as a basis for dose constraints, even without applying any models for normal tissue complication probabilities (NTCP), is based on (some) assumptions that are not met in clinical routine treatment planning. First, and most important, dose-volume histogram (DVH) parameters are usually derived from a single, 'snap-shot' CT-scan, without considering physiological (urinary bladder, intestine) or radiation induced (edema, patient weight loss) changes during radiotherapy. Also, individual variations, or different institutional strategies of delineating organs at risk are rarely considered. Moreover, the reduction of the 3-dimentional dose distribution into a '2dimensl' DVH parameter implies that the localization of the dose within an organ is irrelevant-there are ample examples that this assumption is not justified. Routinely used dose constraints also do not take into account that the residual function of an organ may be

Defining internal target volume (ITV) for hepatocellular carcinoma using four-dimensional CT

International Nuclear Information System (INIS)

X, Mian; Liu Mengzhong; Deng Xiaowu; Zhang Li; Huang Xiaoyan; Liu Hui; Li Qiaoqiao; Hu Yonghong; Cai Ling; Cui Nianji

2007-01-01

Background and purpose: To define individualized internal target volume (ITV) for hepatocellular carcinoma using four-dimensional computed tomography (4DCT). Materials and methods: Gross tumor volumes (GTVs) and clinical target volumes (CTVs) were contoured on all 10 respiratory phases of 4DCT scans in 10 patients with hepatocellular carcinoma. The 3D and 4D treatment plans were performed for each patient using two different planning target volumes (PTVs): (1) PTV 3D was derived from a single CTV plus conventional margins; (2) PTV 4D was derived from ITV 4D , which encompassed all 10 CTVs plus setup margins (SMs). The volumes of PTVs and dose distribution were compared between the two plans. Results: The average PTV volume of the 4D plans (328.4 ± 152.2 cm 3 ) was less than 3D plans (407.0 ± 165.6 cm 3 ). The 4D plans spared more surrounding normal tissues than 3D plans, especially normal liver. Compared with 3D plans, the mean dose to normal liver (MDTNL) decreased from 22.7 to 20.3 Gy. Without increasing the normal tissue complication probability (NTCP), the 4D plans allowed for increasing the calculated dose from 50.4 ± 1.3 to 54.2 ± 2.6 Gy, an average increase of 7.5% (range 4.0-16.0%). Conclusions: The conventional 3D plans can result in geometric miss and include excess normal tissues. The 4DCT-based plans can reduce the target volumes to spare more normal tissues and allow dose escalation compared with 3D plans

The incorporation of specific tissue/nuclide attenuation data into the Anderson method for producing brachytherapy volume-dose histograms

International Nuclear Information System (INIS)

Loft, S.M.; Dale, R.G.

1990-01-01

Anderson (1986) has proposed an analytical method for deriving volume-dose histograms relating to three-dimensional brachytherapy distributions. Because the mathematical transformation allows the otherwise dominant effects of the inverse-square fall-off about individual sources to be effectively suppressed, resulting histograms provide the potential for visually and numerically assessing overall quality of a brachytherapy treatment. In this paper the Anderson equations have been combined with the radial-dose polynomials of Dale, which are applicable to a number of tissue/nuclide combinations, and the predictions of the combined formalism used to further investigate the physical aspects of brachytherapy dosimetry. The problems associated with the dosimetry of low-energy γ-emitters such as 125 I are once again highlighted, as are potential advantages of using a radionuclide with an intermediate γ-ray energy. (author)

Correlation between orbital volume, body mass index, and eyeball position in healthy East asians.

Science.gov (United States)

Yoo, Jun Ho; Lee, Young Hen; Lee, Hwa; Kim, Jung Wan; Chang, Minwook; Park, Minsoo; Baek, Sehyun

2013-05-01

The objectives of this study were measure the orbital volume of healthy Koreans and analyze the differences between orbital tissue volume with respect to age and sex and to assess any correlation between body mass index (BMI), eyeball position, and orbital volume. We retrospectively evaluated the scan results of patients who had undergone orbital computed tomography scans between November 2010 and November 2011. We assessed the scan results of 184 orbits in 92 adults who had no pathology of the orbit. The individuals were classified into 3 groups with respect to age. Orbital volume, effective orbital volume (defined as the difference between orbital and eyeball volume), extraocular muscle volume, orbital fat volume, and transverse globe protrusion were recorded and analyzed. The records of the subjects were reviewed retrospectively, and BMI was calculated. A correlation analysis was performed to investigate the correlation between BMI, eyeball position, and orbital volume. Orbital tissue volume, with the exception of orbital fat volume, was larger in men compared with women. In both sexes, orbital fat volume increased with increasing age, whereas the other volumes decreased. Orbital tissue volumes increased with increasing BMI, but transverse globe protrusion was not significantly related to BMI. In addition, orbital volume and effective orbital volume were positively correlated with transverse globe protrusion. These results provide basic information about the effects of age, sex, and BMI on orbital volume and eyeball position in healthy Koreans. Furthermore, these results will be helpful in the diagnosis of orbital diseases and in planning orbital surgeries.

Nonrigid registration with tissue-dependent filtering of the deformation field

International Nuclear Information System (INIS)

Staring, Marius; Klein, Stefan; Pluim, Josien P W

2007-01-01

In present-day medical practice it is often necessary to nonrigidly align image data. Current registration algorithms do not generally take the characteristics of tissue into account. Consequently, rigid tissue, such as bone, can be deformed elastically, growth of tumours may be concealed, and contrast-enhanced structures may be reduced in volume. We propose a method to locally adapt the deformation field at structures that must be kept rigid, using a tissue-dependent filtering technique. This adaptive filtering of the deformation field results in locally linear transformations without scaling or shearing. The degree of filtering is related to tissue stiffness: more filtering is applied at stiff tissue locations, less at parts of the image containing nonrigid tissue. The tissue-dependent filter is incorporated in a commonly used registration algorithm, using mutual information as a similarity measure and cubic B-splines to model the deformation field. The new registration algorithm is compared with this popular method. Evaluation of the proposed tissue-dependent filtering is performed on 3D computed tomography (CT) data of the thorax and on 2D digital subtraction angiography (DSA) images. The results show that tissue-dependent filtering of the deformation field leads to improved registration results: tumour volumes and vessel widths are preserved rather than affected

A method to estimate the fractional fat volume within a ROI of a breast biopsy for WAXS applications: Animal tissue evaluation

Energy Technology Data Exchange (ETDEWEB)

Tang, Robert Y., E-mail: rx-tang@laurentian.ca [Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); McDonald, Nancy, E-mail: mcdnancye@gmail.com; Laamanen, Curtis, E-mail: cx-laamanen@laurentian.ca [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada); LeClair, Robert J., E-mail: rleclair@laurentian.ca [Department of Physics, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6, Canada and Biomolecular Sciences Program, Laurentian University, 935 Ramsey Lake Road, Sudbury, Ontario P3E 2C6 (Canada)

2014-11-01

Purpose: To develop a method to estimate the mean fractional volume of fat (ν{sup ¯}{sub fat}) within a region of interest (ROI) of a tissue sample for wide-angle x-ray scatter (WAXS) applications. A scatter signal from the ROI was obtained and use of ν{sup ¯}{sub fat} in a WAXS fat subtraction model provided a way to estimate the differential linear scattering coefficient μ{sub s} of the remaining fatless tissue. Methods: The efficacy of the method was tested using animal tissue from a local butcher shop. Formalin fixed samples, 5 mm in diameter 4 mm thick, were prepared. The two main tissue types were fat and meat (fibrous). Pure as well as composite samples consisting of a mixture of the two tissue types were analyzed. For the latter samples, ν{sub fat} for the tissue columns of interest were extracted from corresponding pixels in CCD digital x-ray images using a calibration curve. The means ν{sup ¯}{sub fat} were then calculated for use in a WAXS fat subtraction model. For the WAXS measurements, the samples were interrogated with a 2.7 mm diameter 50 kV beam and the 6° scattered photons were detected with a CdTe detector subtending a solid angle of 7.75 × 10{sup −5} sr. Using the scatter spectrum, an estimate of the incident spectrum, and a scatter model, μ{sub s} was determined for the tissue in the ROI. For the composite samples, a WAXS fat subtraction model was used to estimate the μ{sub s} of the fibrous tissue in the ROI. This signal was compared to μ{sub s} of fibrous tissue obtained using a pure fibrous sample. Results: For chicken and beef composites, ν{sup ¯}{sub fat}=0.33±0.05 and 0.32 ± 0.05, respectively. The subtractions of these fat components from the WAXS composite signals provided estimates of μ{sub s} for chicken and beef fibrous tissue. The differences between the estimates and μ{sub s} of fibrous obtained with a pure sample were calculated as a function of the momentum transfer x. A t-test showed that the mean of the

Molecular, cellular, and tissue engineering

CERN Document Server

Bronzino, Joseph D

2015-01-01

Known as the bible of biomedical engineering, The Biomedical Engineering Handbook, Fourth Edition, sets the standard against which all other references of this nature are measured. As such, it has served as a major resource for both skilled professionals and novices to biomedical engineering. Molecular, Cellular, and Tissue Engineering, the fourth volume of the handbook, presents material from respected scientists with diverse backgrounds in molecular biology, transport phenomena, physiological modeling, tissue engineering, stem cells, drug delivery systems, artificial organs, and personalized medicine. More than three dozen specific topics are examined, including DNA vaccines, biomimetic systems, cardiovascular dynamics, biomaterial scaffolds, cell mechanobiology, synthetic biomaterials, pluripotent stem cells, hematopoietic stem cells, mesenchymal stem cells, nanobiomaterials for tissue engineering, biomedical imaging of engineered tissues, gene therapy, noninvasive targeted protein and peptide drug deliver...

Morphology and function: MR pineal volume and melatonin level in human saliva are correlated.

Science.gov (United States)

Liebrich, Luisa-Sophie; Schredl, Michael; Findeisen, Peter; Groden, Christoph; Bumb, Jan Malte; Nölte, Ingo S

2014-10-01

To investigate the relation between circadian saliva melatonin levels and pineal volume as determined by MRI. Plasma melatonin levels follow a circadian rhythm with a high interindividual variability. In 103 healthy individuals saliva melatonin levels were determined at four time points within 24 h and MRI was performed once (3.0 Tesla, including three-dimensional T2 turbo spin echo [3D-T2-TSE], susceptibility-weighted imaging [SWI]). Pineal volume as well as cyst volume were assessed from multiplanar reconstructed 3D-T2-TSE images. Pineal calcification volume tissue was determined on SWI. To correct for hormonal inactive pineal tissue, cystic and calcified areas were excluded. Sleep quality was assessed with the Landeck Inventory for sleep quality disturbance. Solid and uncalcified pineal volume correlated to melatonin maximum (r = 0.28; P < 0.05) and area under the curve (r = 0.29; P < 0.05). Of interest, solid and uncalcified pineal volume correlated negatively with the sleep rhythm disturbances subscore (r = -0.17; P < 0.05) despite a very homogenous population. Uncalcified solid pineal tissue measured by 3D-T2-TSE and SWI is related to human saliva melatonin levels. The analysis of the sleep quality and pineal volume suggests a linkage between better sleep quality and hormonal active pineal tissue. © 2013 Wiley Periodicals, Inc.

The impact of reconstruction and scanner characterisation on the diagnostic capability of a normal database for [(123)I]FP-CIT SPECT imaging

DEFF Research Database (Denmark)

Dickson, John C; Tossici-Bolt, Livia; Sera, Terez

2017-01-01

for scan normality using the ENC-DAT normal database obtained in well-documented healthy subjects. Patient and normal data were reconstructed with iterative reconstruction with correction for attenuation, scatter and septal penetration (ACSC), the same reconstruction without corrections (IRNC......), and filtered back-projection (FBP) with data quantified using small volume-of-interest (VOI) (BRASS) and large VOI (Southampton) analysis methods. Test performance was assessed with and without system characterisation, using receiver operating characteristics (ROC) analysis for age-independent data and using......BACKGROUND: The use of a normal database for [(123)I]FP-CIT SPECT imaging has been found to be helpful for cases which are difficult to interpret by visual assessment alone, and to improve reproducibility in scan interpretation. The aim of this study was to assess whether the use of different...

The value of magnetic resonance imaging in target volume delineation of base of tongue tumours - A study using flexible surface coils

International Nuclear Information System (INIS)

Ahmed, Merina; Schmidt, Maria; Sohaib, Aslam; Kong, Christine; Burke, Kevin; Richardson, Cheryl; Usher, Marianne; Brennan, Sinead; Riddell, Angela; Davies, Mark; Newbold, Kate; Harrington, Kevin J.; Nutting, Christopher M.

2010-01-01

Introduction: Magnetic resonance imaging (MRI) provides superior diagnostic accuracy over computed tomography (CT) in oropharyngeal tumours. Precise delineation of the gross tumour volume (GTV) is mandatory in radiotherapy planning when a GTV boost is required. CT volume definition in this regard is poor. We studied the feasibility of using flexible surface (flex-L) coils to obtain MR images for MR-CT fusion to assess the benefit of MRI over CT alone in planning base of tongue tumours. Methods: Eight patients underwent CT and MRI radiotherapy planning scans with an immobilisation device. Distortion-corrected T1-weighted post-contrast MR scans were fused to contrast-enhanced planning CT scans. GTV, clinical target and planning target volumes (CTV, PTV) and organs at risk (OAR) were delineated on CT, then on MRI with blinding to the CT images. The volumetric and spatial differences between MRI and CT volumes for GTV, CTV, PTV and OAR were compared. MR image distortions due to field inhomogeneity and non-linear gradients were corrected and the need for such correction was evaluated. Results: The mean primary GTV was larger on MRI (22.2 vs. 9.5 cm 3 , p = 0.05) than CT. The mean primary and nodal GTV (i.e. BOT and macroscopic nodes) was significantly larger on MRI (27.2 vs. 14.4 cm 3 , p = 0.05). The volume overlap index (VOI) between MRI and CT for the primary was 0.34 suggesting that MRI depicts parts of the primary tumour not detected by CT. There was no significant difference in volume delineation between MR and CT for CTV, PTV, nodal CTV and nodal PTV. MRI volumes for brainstem and spinal cord were significantly smaller due to improved organ definition (p = 0.002). Susceptibility and gradient-related distortions were not found to be clinically significant. Conclusion: MRI improves the definition of tongue base tumours and neurological structures. The use of MRI is recommended for GTV dose-escalation techniques to provide precise depiction of GTV and improved

The value of magnetic resonance imaging in target volume delineation of base of tongue tumours - A study using flexible surface coils

Energy Technology Data Exchange (ETDEWEB)

Ahmed, Merina [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Schmidt, Maria [Cancer Research UK Clinical Magnetic Resonance Group, Royal Marsden NHS Foundation Trust, Surrey (United Kingdom); Sohaib, Aslam [Department of Radiology, Royal Marsden NHS Foundation Trust, London (United Kingdom); Kong, Christine; Burke, Kevin [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Richardson, Cheryl; Usher, Marianne [Cancer Research UK Clinical Magnetic Resonance Group, Royal Marsden NHS Foundation Trust, Surrey (United Kingdom); Brennan, Sinead [Department of Radiotherapy, St. James' s Hospital, Dublin (Ireland); Riddell, Angela [Department of Radiology, Royal Marsden NHS Foundation Trust, London (United Kingdom); Davies, Mark; Newbold, Kate [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Harrington, Kevin J; Nutting, Christopher M [Department of Radiotherapy, Royal Marsden NHS Foundation Trust, London (United Kingdom); Institute of Cancer Research, London (United Kingdom)

2010-02-15

Introduction: Magnetic resonance imaging (MRI) provides superior diagnostic accuracy over computed tomography (CT) in oropharyngeal tumours. Precise delineation of the gross tumour volume (GTV) is mandatory in radiotherapy planning when a GTV boost is required. CT volume definition in this regard is poor. We studied the feasibility of using flexible surface (flex-L) coils to obtain MR images for MR-CT fusion to assess the benefit of MRI over CT alone in planning base of tongue tumours. Methods: Eight patients underwent CT and MRI radiotherapy planning scans with an immobilisation device. Distortion-corrected T1-weighted post-contrast MR scans were fused to contrast-enhanced planning CT scans. GTV, clinical target and planning target volumes (CTV, PTV) and organs at risk (OAR) were delineated on CT, then on MRI with blinding to the CT images. The volumetric and spatial differences between MRI and CT volumes for GTV, CTV, PTV and OAR were compared. MR image distortions due to field inhomogeneity and non-linear gradients were corrected and the need for such correction was evaluated. Results: The mean primary GTV was larger on MRI (22.2 vs. 9.5 cm{sup 3}, p = 0.05) than CT. The mean primary and nodal GTV (i.e. BOT and macroscopic nodes) was significantly larger on MRI (27.2 vs. 14.4 cm{sup 3}, p = 0.05). The volume overlap index (VOI) between MRI and CT for the primary was 0.34 suggesting that MRI depicts parts of the primary tumour not detected by CT. There was no significant difference in volume delineation between MR and CT for CTV, PTV, nodal CTV and nodal PTV. MRI volumes for brainstem and spinal cord were significantly smaller due to improved organ definition (p = 0.002). Susceptibility and gradient-related distortions were not found to be clinically significant. Conclusion: MRI improves the definition of tongue base tumours and neurological structures. The use of MRI is recommended for GTV dose-escalation techniques to provide precise depiction of GTV and

Radioiodine therapy in Graves' disease based on tissue-absorbed dose calculations: effect of pre-treatment thyroid volume on clinical outcome

Energy Technology Data Exchange (ETDEWEB)

Reinhardt, Michael J; Joe, Alexius Y; Mallek, Dirk von; Ezziddin, Samer; Palmedo, Holger [Department of Nuclear Medicine, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Brink, Ingo [Department of Nuclear Medicine, University Hospital of Freiburg (Germany); Krause, Thomas M [Department of Nuclear Medicine, Inselspital Bern (Switzerland)

2002-09-01

This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15{+-}9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256{+-}80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses. (orig.)

Radioiodine therapy in Graves' disease based on tissue-absorbed dose calculations: effect of pre-treatment thyroid volume on clinical outcome

International Nuclear Information System (INIS)

Reinhardt, Michael J.; Joe, Alexius Y.; Mallek, Dirk von; Ezziddin, Samer; Palmedo, Holger; Brink, Ingo; Krause, Thomas M.

2002-01-01

This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15±9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256±80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses. (orig.)

Brain regional {alpha}-[{sup 11}C]methyl-L-tryptophan trapping, used as an index of 5-HT synthesis, in healthy adults: absence of an age effect

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Rosa-Neto, Pedro; Benkelfat, Chawki; Leyton, Marco [Department of Neurology and Neurosurgery, Montreal (Canada); McGill University, Department of Psychiatry, Montreal, Quebec (Canada); Sakai, Yojiro [Department of Neurology and Neurosurgery, Montreal (Canada); University of Tokyo, Department of Psychosomatic Medicine, Tokyo (Japan); Morais, Jose A. [McGill University, Department of Geriatrics, Montreal, Quebec (Canada); Diksic, Mirko [Department of Neurology and Neurosurgery, Montreal (Canada)

2007-08-15

Previous functional neuroimaging studies suggest that selective aspects of the brain serotonin (5-HT) system change during the aging process. Here, we assessed the effects of aging on the brain regional {alpha}-[{sup 11}C]methyl-L-tryptophan ({alpha}-[{sup 11}C]MTrp) trapping rate constant (K*; {mu}l.g{sup -1}.min{sup -1}), which, with certain assumptions, could be taken as a proxy of 5-HT synthesis. Thirty-six healthy right-handed subjects had positron emission tomography (PET) scans following injection with {alpha}-[{sup 11}C]MTrp [18 males aged 46.6 {+-} 22.2 years (range 20-80 years) and 18 females aged 33.0 {+-} 15.5 years (range 20-80 years)]. The trapping rate constant, K*, was calculated with the graphical method for irreversible ligands using the sinus-venous input function. A priori selected volumes of interest (VOIs) were defined using an automatic algorithm. VOI analysis showed no correlation between age and brain regional K* values. As reported by others, significant age-related reductions of gray matter were observed in the thalamus and frontal and cingulate cortices; even with partial volume correction there was still no significant relationship between K* and age. Further exploratory SPM voxelwise correlation between age and {alpha}-[{sup 11}C]MTrp trapping, using p = 0.05 (uncorrected), as well as voxel-based morphometry, was in agreement with the VOI analysis. The dissociation between age-related changes in brain anatomy and this index of serotonin synthesis suggests independent mechanisms underlying the normal aging process. (orig.)

Novel whole brain segmentation and volume estimation using quantitative MRI

International Nuclear Information System (INIS)

West, J.; Warntjes, J.B.M.; Lundberg, P.

2012-01-01

Brain segmentation and volume estimation of grey matter (GM), white matter (WM) and cerebro-spinal fluid (CSF) are important for many neurological applications. Volumetric changes are observed in multiple sclerosis (MS), Alzheimer's disease and dementia, and in normal aging. A novel method is presented to segment brain tissue based on quantitative magnetic resonance imaging (qMRI) of the longitudinal relaxation rate R 1 , the transverse relaxation rate R 2 and the proton density, PD. Previously reported qMRI values for WM, GM and CSF were used to define tissues and a Bloch simulation performed to investigate R 1 , R 2 and PD for tissue mixtures in the presence of noise. Based on the simulations a lookup grid was constructed to relate tissue partial volume to the R 1 -R 2 -PD space. The method was validated in 10 healthy subjects. MRI data were acquired using six resolutions and three geometries. Repeatability for different resolutions was 3.2% for WM, 3.2% for GM, 1.0% for CSF and 2.2% for total brain volume. Repeatability for different geometries was 8.5% for WM, 9.4% for GM, 2.4% for CSF and 2.4% for total brain volume. We propose a new robust qMRI-based approach which we demonstrate in a patient with MS. (orig.)

Novel whole brain segmentation and volume estimation using quantitative MRI

Energy Technology Data Exchange (ETDEWEB)

West, J. [Linkoeping University, Radiation Physics, Department of Medical and Health Sciences, Faculty of Health Sciences, Linkoeping (Sweden); Linkoeping University, Center for Medical Imaging Science and Visualization (CMIV), Linkoeping (Sweden); SyntheticMR AB, Linkoeping (Sweden); Warntjes, J.B.M. [Linkoeping University, Center for Medical Imaging Science and Visualization (CMIV), Linkoeping (Sweden); SyntheticMR AB, Linkoeping (Sweden); Linkoeping University and Department of Clinical Physiology UHL, County Council of Oestergoetland, Clinical Physiology, Department of Medical and Health Sciences, Faculty of Health Sciences, Linkoeping (Sweden); Lundberg, P. [Linkoeping University, Center for Medical Imaging Science and Visualization (CMIV), Linkoeping (Sweden); Linkoeping University and Department of Radiation Physics UHL, County Council of Oestergoetland, Radiation Physics, Department of Medical and Health Sciences, Faculty of Health Sciences, Linkoeping (Sweden); Linkoeping University and Department of Radiology UHL, County Council of Oestergoetland, Radiology, Department of Medical and Health Sciences, Faculty of Health Sciences, Linkoeping (Sweden)

2012-05-15

Brain segmentation and volume estimation of grey matter (GM), white matter (WM) and cerebro-spinal fluid (CSF) are important for many neurological applications. Volumetric changes are observed in multiple sclerosis (MS), Alzheimer's disease and dementia, and in normal aging. A novel method is presented to segment brain tissue based on quantitative magnetic resonance imaging (qMRI) of the longitudinal relaxation rate R{sub 1}, the transverse relaxation rate R{sub 2} and the proton density, PD. Previously reported qMRI values for WM, GM and CSF were used to define tissues and a Bloch simulation performed to investigate R{sub 1}, R{sub 2} and PD for tissue mixtures in the presence of noise. Based on the simulations a lookup grid was constructed to relate tissue partial volume to the R{sub 1}-R{sub 2}-PD space. The method was validated in 10 healthy subjects. MRI data were acquired using six resolutions and three geometries. Repeatability for different resolutions was 3.2% for WM, 3.2% for GM, 1.0% for CSF and 2.2% for total brain volume. Repeatability for different geometries was 8.5% for WM, 9.4% for GM, 2.4% for CSF and 2.4% for total brain volume. We propose a new robust qMRI-based approach which we demonstrate in a patient with MS. (orig.)

A PET/MRI study towards finding the optimal ["1"8F]Fluciclovine PET protocol for detection and characterisation of primary prostate cancer

International Nuclear Information System (INIS)

Elschot, Mattijs; Sandsmark, Elise; Tessem, May-Britt; Selnaes, Kirsten M.; Bathen, Tone F.; Krueger-Stokke, Brage; Stoerkersen, Oeystein; Moestue, Siver A.; Bertilsson, Helena

2017-01-01

["1"8F]Fluciclovine PET imaging shows promise for the assessment of prostate cancer. The purpose of this PET/MRI study is to optimise the PET imaging protocol for detection and characterisation of primary prostate cancer, by quantitative evaluation of the dynamic uptake of ["1"8F]Fluciclovine in cancerous and benign tissue. Patients diagnosed with high-risk primary prostate cancer underwent an integrated ["1"8F]Fluciclovine PET/MRI exam before robot-assisted radical prostatectomy with extended pelvic lymph node dissection. Volumes-of-interest (VOIs) of selected organs (prostate, bladder, blood pool) and sub-glandular prostate structures (tumour, benign prostatic hyperplasia (BPH), inflammation, healthy tissue) were delineated on T2-weighted MR images, using whole-mount histology samples as a reference. Three candidate windows for optimal PET imaging were identified based on the dynamic curves of the mean and maximum standardised uptake value (SUV_m_e_a_n and SUV_m_a_x, respectively). The statistical significance of differences in SUV between VOIs were analysed using Wilcoxon rank sum tests (p<0.05, adjusted for multiple testing). Twenty-eight (28) patients [median (range) age: 66 (55-72) years] were included. An early (W1: 5-10 minutes post-injection) and two late candidate windows (W2: 18-23; W3: 33-38 minutes post-injection) were selected. Late compared with early imaging was better able to distinguish between malignant and benign tissue [W3, SUV_m_e_a_n: tumour vs. BPH 2.5 vs. 2.0 (p<0.001), tumour vs. inflammation 2.5 vs. 1.7 (p<0.001), tumour vs. healthy tissue 2.5 vs. 2.0 (p<0.001); W1, SUV_m_e_a_n: tumour vs. BPH 3.1 vs. 3.1 (p=0.771), tumour vs inflammation 3.1 vs. 2.2 (p=0.021), tumour vs. healthy tissue 3.1 vs. 2.5 (p<0.001)] as well as between high-grade and low/intermediate-grade tumours (W3, SUV_m_e_a_n: 2.6 vs. 2.1 (p=0.040); W1, SUV_m_e_a_n: 3.1 vs. 2.8 (p=0.173)). These differences were relevant to the peripheral zone, but not the central gland

A PET/MRI study towards finding the optimal [{sup 18}F]Fluciclovine PET protocol for detection and characterisation of primary prostate cancer

Energy Technology Data Exchange (ETDEWEB)

Elschot, Mattijs; Sandsmark, Elise; Tessem, May-Britt [NTNU, Norwegian University of Science and Technology, Deparment of Circulation and Medical Imaging, Faculty of Medicine, Trondheim (Norway); Selnaes, Kirsten M.; Bathen, Tone F. [NTNU, Norwegian University of Science and Technology, Deparment of Circulation and Medical Imaging, Faculty of Medicine, Trondheim (Norway); Trondheim University Hospital, St. Olavs Hospital, Trondheim (Norway); Krueger-Stokke, Brage [NTNU, Norwegian University of Science and Technology, Deparment of Circulation and Medical Imaging, Faculty of Medicine, Trondheim (Norway); Trondheim University Hospital, Department of Radiology, St. Olavs Hospital, Trondheim (Norway); Stoerkersen, Oeystein [Trondheim University Hospital, Department of Pathology, St. Olavs Hospital, Trondheim (Norway); Moestue, Siver A. [NTNU, Norwegian University of Science and Technology, Deparment of Circulation and Medical Imaging, Faculty of Medicine, Trondheim (Norway); NTNU, Norwegian University of Science and Technology, Department of Laboratory Medicine, Children' s and Women' s Health, Faculty of Medicine, Trondheim (Norway); Bertilsson, Helena [Trondheim University Hospital, Department of Urology, St. Olavs Hospital, Trondheim (Norway); NTNU, Norwegian University of Science and Technology, Department of Cancer Research and Molecular Medicine, Faculty of Medicine, Trondheim (Norway)

2017-04-15

[{sup 18}F]Fluciclovine PET imaging shows promise for the assessment of prostate cancer. The purpose of this PET/MRI study is to optimise the PET imaging protocol for detection and characterisation of primary prostate cancer, by quantitative evaluation of the dynamic uptake of [{sup 18}F]Fluciclovine in cancerous and benign tissue. Patients diagnosed with high-risk primary prostate cancer underwent an integrated [{sup 18}F]Fluciclovine PET/MRI exam before robot-assisted radical prostatectomy with extended pelvic lymph node dissection. Volumes-of-interest (VOIs) of selected organs (prostate, bladder, blood pool) and sub-glandular prostate structures (tumour, benign prostatic hyperplasia (BPH), inflammation, healthy tissue) were delineated on T2-weighted MR images, using whole-mount histology samples as a reference. Three candidate windows for optimal PET imaging were identified based on the dynamic curves of the mean and maximum standardised uptake value (SUV{sub mean} and SUV{sub max}, respectively). The statistical significance of differences in SUV between VOIs were analysed using Wilcoxon rank sum tests (p<0.05, adjusted for multiple testing). Twenty-eight (28) patients [median (range) age: 66 (55-72) years] were included. An early (W1: 5-10 minutes post-injection) and two late candidate windows (W2: 18-23; W3: 33-38 minutes post-injection) were selected. Late compared with early imaging was better able to distinguish between malignant and benign tissue [W3, SUV{sub mean}: tumour vs. BPH 2.5 vs. 2.0 (p<0.001), tumour vs. inflammation 2.5 vs. 1.7 (p<0.001), tumour vs. healthy tissue 2.5 vs. 2.0 (p<0.001); W1, SUV{sub mean}: tumour vs. BPH 3.1 vs. 3.1 (p=0.771), tumour vs inflammation 3.1 vs. 2.2 (p=0.021), tumour vs. healthy tissue 3.1 vs. 2.5 (p<0.001)] as well as between high-grade and low/intermediate-grade tumours (W3, SUV{sub mean}: 2.6 vs. 2.1 (p=0.040); W1, SUV{sub mean}: 3.1 vs. 2.8 (p=0.173)). These differences were relevant to the peripheral zone, but

Radiobiology in clinical radiation therapy - Part III: Normal tissue damage

International Nuclear Information System (INIS)

Travis, Elizabeth L.

1996-01-01

Objective: This is the third part of a course designed for residents in radiation oncology preparing for their boards. This part of the course will focus on the mechanisms underlying damage in normal tissues. Although conventional wisdom long held that killing and depletion of a critical cell(s) in a tissue was responsible for the later expression of damage, histopathologic changes in normal tissue can now be explained and better understood in terms of the new molecular biology. The concept that depletion of a single cell type is responsible for the observed histopathologic changes in normal tissues has been replaced by the hypothesis that damage results from the interaction of many different cell systems, including epithelial, endothelial, macrophages and fibroblasts, via the production of specific autocrine, paracrine and endocrine growth factors. A portion of this course will discuss the clinical and experimental data on the production and interaction of those cytokines and cell systems considered to be critical to tissue damage. It had long been suggested that interindividual differences in radiation-induced normal tissue damage was genetically regulated, at least in part. Both clinical and experimental data supported this hypothesis but it is the recent advances in human and mouse molecular genetics which have provided the tools to dissect out the genetic component of normal tissue damage. These data will be presented and related to the potential to develop genetic markers to identify sensitive individuals. The impact on clinical outcome of the ability to identify prospectively sensitive patients will be discussed. Clinically it is well-accepted that the volume of tissue irradiated is a critical factor in determining tissue damage. A profusion of mathematical models for estimating dose-volume relationships in a number of organs have been published recently despite the fact that little data are available to support these models. This course will review the

Influence of volume on intraoperatively irradiated canine ureters

International Nuclear Information System (INIS)

Gillette, S.M.; Powers, B.E.; Thames, H.D.; Vujaskovic, Z.; LaRue, S.M.; Park, R.D.; Gillette, E.L.

1995-01-01

Purpose/Objective: Intraoperative radiation therapy (IORT) is used to deliver high single doses of radiation to the tumor bed following surgical removal of various abdominal malignancies. The advantage of IORT is the ability to remove sensitive normal tissues from the treatment field and limit the volume of normal tissue irradiated. The purpose of this study was to determine dose-volume relationships for retroperitoneal tissues. Materials and methods: 134 adult beagle dogs were irradiated to the surgically exposed paraaortic area. Normal tissues included in the treatment field were aorta, peripheral nerve, ureter, bone and the muscle. Groups of 4 - 8 dogs were irradiated to doses ranging from 18 - 54 Gy for a 2x5 cm field, from 12 - 46 Gy for a 4x5 cm field, and 12 - 42 Gy to an 8x5 cm field. The radiations were done using 6 MeV electrons from a linear accelerator. Dogs were observed for three years after radiation at which time they were euthanatized, perfused and tissues taken for histologic and histomorphometric evaluation. Transverse sections of the ureter were taken from the proximal, middle and distal segments. Histologically, proximal portions of the ureters with greater than 5 times normal diameter were considered to have severe hydroureter. Ureteral strictures and hydroneophrosis were evaluated by excretory urograms. Excretory urograms were done prior to treatment and annually after treatment or prior to necropsy for each dog in the experiments. A grading system was devised for predicting ureteral stenosis based on ureteral and renal pelvic dilatation. Results: A strong dose and volume relationship was identified for ureteral injury using the mixture model analysis which takes into account latency as well as dose. Subsequent to earlier edema, fibrin and vessel damage, progressive fibrosis developed and likely caused uteral stricture resulting in hydroureter. Severe hydroureter was observed as early as three months. The ED 50 for hydroureter determined

Ray tissues as an indirect measure of relative sap-sugar concentration in sugar maple

Science.gov (United States)

Peter W. Garrett; Kenneth R. Dudzik; Kenneth R. Dudzik

1989-01-01

Attempts to correlate ray tissue as a percentage of total wood volume with sap-sugar concentrations of sugar maple progenies were unsuccessful. These results raise doubts about our ability to use a relatively constant value such as ray-tissue volume in a selection program designed to increase the sap-sugar concentration of sugar maple seedlings.

Multifactorial Optimization of Contrast-Enhanced Nanofocus Computed Tomography for Quantitative Analysis of Neo-Tissue Formation in Tissue Engineering Constructs.

Directory of Open Access Journals (Sweden)

Maarten Sonnaert

Full Text Available To progress the fields of tissue engineering (TE and regenerative medicine, development of quantitative methods for non-invasive three dimensional characterization of engineered constructs (i.e. cells/tissue combined with scaffolds becomes essential. In this study, we have defined the most optimal staining conditions for contrast-enhanced nanofocus computed tomography for three dimensional visualization and quantitative analysis of in vitro engineered neo-tissue (i.e. extracellular matrix containing cells in perfusion bioreactor-developed Ti6Al4V constructs. A fractional factorial 'design of experiments' approach was used to elucidate the influence of the staining time and concentration of two contrast agents (Hexabrix and phosphotungstic acid and the neo-tissue volume on the image contrast and dataset quality. Additionally, the neo-tissue shrinkage that was induced by phosphotungstic acid staining was quantified to determine the operating window within which this contrast agent can be accurately applied. For Hexabrix the staining concentration was the main parameter influencing image contrast and dataset quality. Using phosphotungstic acid the staining concentration had a significant influence on the image contrast while both staining concentration and neo-tissue volume had an influence on the dataset quality. The use of high concentrations of phosphotungstic acid did however introduce significant shrinkage of the neo-tissue indicating that, despite sub-optimal image contrast, low concentrations of this staining agent should be used to enable quantitative analysis. To conclude, design of experiments allowed us to define the most optimal staining conditions for contrast-enhanced nanofocus computed tomography to be used as a routine screening tool of neo-tissue formation in Ti6Al4V constructs, transforming it into a robust three dimensional quality control methodology.

Computerized detection of diffuse lung disease in MDCT: the usefulness of statistical texture features

International Nuclear Information System (INIS)

Wang Jiahui; Li Qiang; Li Feng; Doi Kunio

2009-01-01

Accurate detection of diffuse lung disease is an important step for computerized diagnosis and quantification of this disease. It is also a difficult clinical task for radiologists. We developed a computerized scheme to assist radiologists in the detection of diffuse lung disease in multi-detector computed tomography (CT). Two radiologists selected 31 normal and 37 abnormal CT scans with ground glass opacity, reticular, honeycombing and nodular disease patterns based on clinical reports. The abnormal cases in our database must contain at least an abnormal area with a severity of moderate or severe level that was subjectively rated by the radiologists. Because statistical texture features may lack the power to distinguish a nodular pattern from a normal pattern, the abnormal cases that contain only a nodular pattern were excluded. The areas that included specific abnormal patterns in the selected CT images were then delineated as reference standards by an expert chest radiologist. The lungs were first segmented in each slice by use of a thresholding technique, and then divided into contiguous volumes of interest (VOIs) with a 64 x 64 x 64 matrix size. For each VOI, we determined and employed statistical texture features, such as run-length and co-occurrence matrix features, to distinguish abnormal from normal lung parenchyma. In particular, we developed new run-length texture features with clear physical meanings to considerably improve the accuracy of our detection scheme. A quadratic classifier was employed for distinguishing between normal and abnormal VOIs by the use of a leave-one-case-out validation scheme. A rule-based criterion was employed to further determine whether a case was normal or abnormal. We investigated the impact of new and conventional texture features, VOI size and the dimensionality for regions of interest on detecting diffuse lung disease. When we employed new texture features for 3D VOIs of 64 x 64 x 64 voxels, our system achieved the

Quantification of tumor vessels in glioblastoma patients using time-of-flight angiography at 7 Tesla: a feasibility study.

Directory of Open Access Journals (Sweden)

Alexander Radbruch

Full Text Available PURPOSE: To analyze if tumor vessels can be visualized, segmented and quantified in glioblastoma patients with time of flight (ToF angiography at 7 Tesla and multiscale vessel enhancement filtering. MATERIALS AND METHODS: Twelve patients with newly diagnosed glioblastoma were examined with ToF angiography (TR = 15 ms, TE = 4.8 ms, flip angle = 15°, FOV = 160 × 210 mm(2, voxel size: 0.31 × 0.31 × 0.40 mm(3 on a whole-body 7 T MR system. A volume of interest (VOI was placed within the border of the contrast enhancing part on T1-weighted images of the glioblastoma and a reference VOI was placed in the non-affected contralateral white matter. Automated segmentation and quantification of vessels within the two VOIs was achieved using multiscale vessel enhancement filtering in ImageJ. RESULTS: Tumor vessels were clearly visible in all patients. When comparing tumor and the reference VOI, total vessel surface (45.3 ± 13.9 mm(2 vs. 29.0 ± 21.0 mm(2 (p<0.035 and number of branches (3.5 ± 1.8 vs. 1.0 ± 0.6 (p<0.001 per cubic centimeter were significantly higher, while mean vessel branch length was significantly lower (3.8 ± 1.5 mm vs 7.2 ± 2.8 mm (p<0.001 in the tumor. DISCUSSION: ToF angiography at 7-Tesla MRI enables characterization and quantification of the internal vascular morphology of glioblastoma and may be used for the evaluation of therapy response within future studies.

Psychophysical and cerebral responses to heat stimulation in patients with central pain, painless central sensory loss, and in healthy persons.

Science.gov (United States)

Casey, Kenneth L; Geisser, Michael; Lorenz, Jürgen; Morrow, Thomas J; Paulson, Pamela; Minoshima, Satoshi

2012-02-01

Patients with central pain (CP) typically have chronic pain within an area of reduced pain and temperature sensation, suggesting an impairment of endogenous pain modulation mechanisms. We tested the hypothesis that some brain structures normally activated by cutaneous heat stimulation would be hyperresponsive among patients with CP but not among patients with a central nervous system lesion causing a loss of heat or nociceptive sensation with no pain (NP). We used H(2)(15)O positron emission tomography to measure, in 15 healthy control participants, 10 NP patients, and 10 CP patients, increases in regional cerebral blood flow among volumes of interest (VOI) from the resting (no stimulus) condition during bilateral contact heat stimulation at heat detection, heat pain threshold, and heat pain tolerance levels. Both patient groups had a reduced perception of heat intensity and unpleasantness on the clinically affected side and a bilateral impairment of heat detection. Compared with the HC group, both NP and CP patients had more hyperactive and hypoactive VOI in the resting state and more hyperresponsive and hyporesponsive VOI during heat stimulation. Compared with NP patients, CP patients had more hyperresponsive VOI in the intralaminar thalamus and sensory-motor cortex during heat stimulation. Our results show that focal CNS lesions produce bilateral sensory deficits and widespread changes in the nociceptive excitability of the brain. The increased nociceptive excitability within the intralaminar thalamus and sensory-motor cortex of our sample of CP patients suggests an underlying pathophysiology for the pain in some central pain syndromes. Published by Elsevier B.V.

The Relationship Between Local Recurrence and Radiotherapy Treatment Volume for Soft Tissue Sarcomas Treated With External Beam Radiotherapy and Function Preservation Surgery

Energy Technology Data Exchange (ETDEWEB)

Dickie, Colleen I., E-mail: Colleen.dickie@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Griffin, Anthony M. [Division of Orthopaedic Surgery, University Musculoskeletal Oncology Unit, Mount Sinai Hospital, Toronto (Canada); University of Toronto, Toronto (Canada); Parent, Amy L. [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Chung, Peter W.M.; Catton, Charles N. [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); University of Toronto, Toronto (Canada); Svensson, Jon [AngliaRuskin University, Cambridge (United Kingdom); Ferguson, Peter C.; Wunder, Jay S.; Bell, Robert S. [Division of Orthopaedic Surgery, University Musculoskeletal Oncology Unit, Mount Sinai Hospital, Toronto (Canada); University of Toronto, Toronto (Canada); Sharpe, Michael B.; O' Sullivan, Brian [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); University of Toronto, Toronto (Canada)

2012-03-15

Purpose: To examine the geometric relationship between local recurrence (LR) and external beam radiotherapy (RT) volumes for soft-tissue sarcoma (STS) patients treated with function-preserving surgery and RT. Methods and Materials: Sixty of 768 (7.8%) STS patients treated with combined therapy within our institution from 1990 through 2006 developed an LR. Thirty-two received preoperative RT, 16 postoperative RT, and 12 preoperative RT plus a postoperative boost. Treatment records, RT simulation images, and diagnostic MRI/CT data sets of the original and LR disease were retrospectively compared. For LR location analysis, three RT target volumes were defined according to the International Commission on Radiation Units and Measurements 29 as follows: (1) the gross tumor or operative bed; (2) the treatment volume (TV) extending 5 cm longitudinally beyond the tumor or operative bed unless protected by intact barriers to spread and at least 1-2 cm axially (the TV was enclosed by the isodose curve representing the prescribed target absorbed dose [TAD] and accounted for target/patient setup uncertainty and beam characteristics), and (3) the irradiated volume (IRV) that received at least 50% of the TAD, including the TV. LRs were categorized as developing in field within the TV, marginal (on the edge of the IRV), and out of field (occurring outside of the IRV). Results: Forty-nine tumors relapsed in field (6.4% overall). Nine were out of field (1.1% overall), and 2 were marginal (0.3% overall). Conclusions: The majority of STS tumors recur in field, indicating that the incidence of LR may be affected more by differences in biologic and molecular characteristics rather than aberrations in RT dose or target volume coverage. In contrast, only two patients relapsed at the IRV boundary, suggesting that the risk of a marginal relapse is low when the TV is appropriately defined. These data support the accurate delivery of optimal RT volumes in the most precise way using advanced

The Relationship Between Local Recurrence and Radiotherapy Treatment Volume for Soft Tissue Sarcomas Treated With External Beam Radiotherapy and Function Preservation Surgery

International Nuclear Information System (INIS)

Dickie, Colleen I.; Griffin, Anthony M.; Parent, Amy L.; Chung, Peter W.M.; Catton, Charles N.; Svensson, Jon; Ferguson, Peter C.; Wunder, Jay S.; Bell, Robert S.; Sharpe, Michael B.; O’Sullivan, Brian

2012-01-01

Purpose: To examine the geometric relationship between local recurrence (LR) and external beam radiotherapy (RT) volumes for soft-tissue sarcoma (STS) patients treated with function-preserving surgery and RT. Methods and Materials: Sixty of 768 (7.8%) STS patients treated with combined therapy within our institution from 1990 through 2006 developed an LR. Thirty-two received preoperative RT, 16 postoperative RT, and 12 preoperative RT plus a postoperative boost. Treatment records, RT simulation images, and diagnostic MRI/CT data sets of the original and LR disease were retrospectively compared. For LR location analysis, three RT target volumes were defined according to the International Commission on Radiation Units and Measurements 29 as follows: (1) the gross tumor or operative bed; (2) the treatment volume (TV) extending 5 cm longitudinally beyond the tumor or operative bed unless protected by intact barriers to spread and at least 1–2 cm axially (the TV was enclosed by the isodose curve representing the prescribed target absorbed dose [TAD] and accounted for target/patient setup uncertainty and beam characteristics), and (3) the irradiated volume (IRV) that received at least 50% of the TAD, including the TV. LRs were categorized as developing in field within the TV, marginal (on the edge of the IRV), and out of field (occurring outside of the IRV). Results: Forty-nine tumors relapsed in field (6.4% overall). Nine were out of field (1.1% overall), and 2 were marginal (0.3% overall). Conclusions: The majority of STS tumors recur in field, indicating that the incidence of LR may be affected more by differences in biologic and molecular characteristics rather than aberrations in RT dose or target volume coverage. In contrast, only two patients relapsed at the IRV boundary, suggesting that the risk of a marginal relapse is low when the TV is appropriately defined. These data support the accurate delivery of optimal RT volumes in the most precise way using advanced

Experimental investigation of factors affecting the absolute recovery coefficients in iodine-124 PET lesion imaging

International Nuclear Information System (INIS)

Jentzen, Walter

2010-01-01

The use of recovery coefficients (RCs) in 124 I PET lesion imaging is a simple method to correct the imaged activity concentration (AC) primarily for the partial-volume effect and, to a minor extent, for the prompt gamma coincidence effect. The aim of this phantom study was to experimentally investigate a number of various factors affecting the 124 I RCs. Three RC-based correction approaches were considered. These approaches differ with respect to the volume of interest (VOI) drawn, which determines the imaged AC and the RCs: a single voxel VOI containing the maximum value (maximum RC), a spherical VOI with a diameter of the scanner resolution (resolution RC) and a VOI equaling the physical object volume (isovolume RC). Measurements were performed using mainly a stand-alone PET scanner (EXACT HR + ) and a latest-generation PET/CT scanner (BIOGRAPH mCT). The RCs were determined using a cylindrical phantom containing spheres or rotational ellipsoids and were derived from images acquired with a reference acquisition protocol. For each type of RC, the influence of the following factors on the RC was assessed: object shape, background activity spill in and iterative image reconstruction parameters. To evaluate the robustness of the RC-based correction approaches, the percentage deviation between RC-corrected and true ACs was determined from images acquired with a clinical acquisition protocol of different AC regimes. The observed results of the shape and spill-in effects were compared with simulation data derived from a convolution-based model. The study demonstrated that the shape effect was negligible and, therefore, was in agreement with theoretical expectations. In contradiction to the simulation results, the observed spill-in effect was unexpectedly small. To avoid variations in the determination of RCs due to reconstruction parameter changes, image reconstruction with a pixel length of about one-third or less of the scanner resolution and an OSEM 1 x 32 algorithm

Soft tissue segmentation and 3D display from computerized tomography and magnetic resonance imaging

International Nuclear Information System (INIS)

Fan, R.T.; Trivedi, S.S.; Fellingham, L.L.; Gamboa-Aldeco, A.; Hedgcock, M.W.

1987-01-01

Volume calculation and 3D display of human anatomy facilitate a physician's diagnosis, treatment, and evaluation. Accurate segmentation of soft tissue structures is a prerequisite for such volume calculations and 3D displays, but segmentation by hand-outlining structures is often tedious and time-consuming. In this paper, methods based on analysis of statistics of image gray level are applied to segmentation of soft tissue in medical images, with the goal of making segmentation automatic or semi-automatic. The resulting segmented images, volume calculations, and 3D displays are analyzed and compared with results based on physician-drawn outlines as well as actual volume measurements

Seismic Imaging of the Lesser Antilles Subduction Zone Using S-to-P Receiver Functions: Insights From VoiLA

Science.gov (United States)

Chichester, B.; Rychert, C.; Harmon, N.; Rietbrock, A.; Collier, J.; Henstock, T.; Goes, S. D. B.; Kendall, J. M.; Krueger, F.

2017-12-01

In the Lesser Antilles subduction zone Atlantic oceanic lithosphere, expected to be highly hydrated, is being subducted beneath the Caribbean plate. Water and other volatiles from the down-going plate are released and cause the overlying mantle to melt, feeding volcanoes with magma and hence forming the volcanic island arc. However, the depths and pathways of volatiles and melt within the mantle wedge are not well known. Here, we use S-to-P receiver functions to image seismic velocity contrasts with depth within the subduction zone in order to constrain the release of volatiles and the presence of melt in the mantle wedge, as well as slab structure and arc-lithosphere structure. We use data from 55-80° epicentral distances recorded by 32 recovered broadband ocean-bottom seismometers that were deployed during the 2016-2017 Volatiles in the Lesser Antilles (VoiLA) project for 15 months on the back- and fore-arc. The S-to-P receiver functions are calculated using two methods: extended time multi-taper deconvolution followed by migration to depth to constrain 3-D discontinuity structure of the subduction zone; and simultaneous deconvolution to determine structure beneath single stations. In the south of the island arc, we image a velocity increase with depth associated with the Moho at depths of 32-40 ± 4 km on the fore- and back-arc, consistent with various previous studies. At depths of 65-80 ± 4 km beneath the fore-arc we image a strong velocity decrease with depth that is west-dipping. At 96-120 ± 5 km beneath the fore-arc, we image a velocity increase with depth that is also west-dipping. The dipping negative-positive phase could represent velocity contrasts related to the top of the down-going plate, a feature commonly imaged in subduction zone receiver function studies. The negative phase is strong, so there may also be contributions to the negative velocity discontinuity from slab dehydration and/or mantle wedge serpentinization in the fore-arc.

Definition of internal target volume and domestric study for hepatocellular carcinoma using four-dimensional CT

International Nuclear Information System (INIS)

Xi Mian; Liu Mengzhong; Deng Xiaowu; Zhang Li; Huang Xiaoyan; Cai Ling

2009-01-01

Objective: To define individualized internal target volume (ITV) for hepatocellular carcinoma using four-dimensional (4D) CT, and to compare the differences in target volume definition and dose distribution among 3D, 4D and respiratory-gated plans. Methods: 4DCT scanning was obtained for 12 patients with hepatocellular. Gross tumor volume (GTV), clinical target volume (CTV) and normal tissues were contoured on all 10 respiratory phases of 4DCT images. The 3D, 4D and gated treatment plans were prepared for each patient using three different planning target volumes (PTVs): 1) PTV 3D was derived from a single CTV plus conventional margins; 2) PTV 4D was derived from ITV 4D , which encompassed all 10 CTVs plus setup margins (SMs); 3) PT Gating was derived from ITV Gating , which encompassed 3 CTVs within gating-window at end-expiration plus SMs. The PTV volume and dose distribution were compared among different plans. Results: The PTV3D was the largest in all 12 patients, but still missed partial target volume in 5 patients when comparing with PTV4D. Both the 4D plans and the gated plans spared more normal tissues than the 3D plans, especially the liver. Without increasing normal tissue dose, the 4D plans allowed for increasing the calculated dose from (50.8 ± 2.0) Gy (3D plans) to (54.7 ± 3.3) Gy, and the gated plans could further increase the dose to (58.0 ± 3.9) Gy. Conclusions: The 4DCT-based plans can ensure optimal target coverage with less irradiation of normal tissues and allow dose escalation when compared with 3D plans. Respiratory gated radiotherapy can further reduce the target volumes to spare more surrounding tissues, especially for patients with large extent of respiratory mobility. (authors)

A randomized, controlled, double-blind crossover study on the effects of 1-L infusions of 6% hydroxyethyl starch suspended in 0.9% saline (voluven) and a balanced solution (Plasma Volume Redibag) on blood volume, renal blood flow velocity, and renal cortical tissue perfusion in healthy volunteers.

Science.gov (United States)

Chowdhury, Abeed H; Cox, Eleanor F; Francis, Susan T; Lobo, Dileep N

2014-05-01

We compared the effects of intravenous administration of 6% hydroxyethyl starch (maize-derived) in 0.9% saline (Voluven; Fresenius Kabi, Runcorn, United Kingdom) and a "balanced" preparation of 6% hydroxyethyl starch (potato-derived) [Plasma Volume Redibag (PVR); Baxter Healthcare, Thetford, United Kingdom] on renal blood flow velocity and renal cortical tissue perfusion in humans using magnetic resonance imaging. Hyperchloremia resulting from 0.9% saline infusion may adversely affect renal hemodynamics when compared with balanced crystalloids. This phenomenon has not been studied with colloids. Twelve healthy adult male subjects received 1-L intravenous infusions of Voluven or PVR over 30 minutes in a randomized, double-blind manner, with crossover studies 7 to 10 days later. Magnetic resonance imaging proceeded for 60 minutes after commencement of infusion to measure renal artery blood flow velocity and renal cortical perfusion. Blood was sampled, and weight was recorded at 0, 30, 60, 120, 180, and 240 minutes. Mean peak serum chloride concentrations were 108 and 106 mmol/L, respectively, after Voluven and PVR infusion (P = 0.032). Changes in blood volume (P = 0.867), strong ion difference (P = 0.219), and mean renal artery flow velocity (P = 0.319) were similar. However, there was a significant increase in mean renal cortical tissue perfusion after PVR when compared with Voluven (P = 0.033). There was no difference in urinary neutrophil gelatinase-associated liopcalin to creatinine ratios after the infusion (P = 0.164). There was no difference in the blood volume-expanding properties of the 2 preparations of 6% hydroxyethyl starch. The balanced starch produced an increase in renal cortical tissue perfusion, a phenomenon not seen with starch in 0.9% saline.

Radioiodine therapy in Graves' disease based on tissue-absorbed dose calculations: effect of pre-treatment thyroid volume on clinical outcome

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Reinhardt, Michael J.; Joe, Alexius Y.; Mallek, Dirk von; Ezziddin, Samer; Palmedo, Holger [Department of Nuclear Medicine, University Hospital of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn (Germany); Brink, Ingo [Department of Nuclear Medicine, University Hospital of Freiburg (Germany); Krause, Thomas M. [Department of Nuclear Medicine, Inselspital Bern (Switzerland)

2002-09-01

This study was performed with three aims. The first was to analyse the effectiveness of radioiodine therapy in Graves' disease patients with and without goitres under conditions of mild iodine deficiency using several tissue-absorbed doses. The second aim was to detect further parameters which might be predictive for treatment outcome. Finally, we wished to determine the deviation of the therapeutically achieved dose from that intended. Activities of 185-2,220 MBq radioiodine were calculated by means of Marinelli's formula to deliver doses of 150, 200 or 300 Gy to the thyroids of 224 patients with Graves' disease and goitres up to 130 ml in volume. Control of hyperthyroidism, change in thyroid volume and thyrotropin-receptor antibodies were evaluated 15{+-}9 months after treatment for each dose. The results were further evaluated with respect to pre-treatment parameters which might be predictive for therapy outcome. Thyroidal radioiodine uptake was measured every day during therapy to determine the therapeutically achieved target dose and its coefficient of variation. There was a significant dose dependency in therapeutic outcome: frequency of hypothyroidism increased from 27.4% after 150 Gy to 67.7% after 300 Gy, while the frequency of persistent hyperthyroidism decreased from 27.4% after 150 Gy to 8.1% after 300 Gy. Patients who became hypothyroid had a maximum thyroid volume of 42 ml and received a target dose of 256{+-}80 Gy. The coefficient of variation for the achieved target dose ranged between 27.7% for 150 Gy and 17.8% for 300 Gy. When analysing further factors which might influence therapeutic outcome, only pre-treatment thyroid volume showed a significant relationship to the result of treatment. It is concluded that a target dose of 250 Gy is essential to achieve hypothyroidism within 1 year after radioiodine therapy in Graves' disease patients with goitres up to 40 ml in volume. Patients with larger goitres might need higher doses

The evaluation of tissue mass loss in the incision line of prostate with benign hyperplasia performed using holmium laser and cutting electrode.

Science.gov (United States)

Szewczyk, Mariusz; Jesionek-Kupnicka, Dorota; Lipiński, Marek Ireneusz; Lipinski, Piotr; Różański, Waldemar

2014-01-01

The aim of this study is to compare the changes in the incision line of prostatic adenoma using a monopolar cutting electrode and holmium laser, as well as the assessment of associated tissue mass and volume loss of benign prostatic hyperplasia (BPH). The material used in this study consisted of 74 preparations of prostatic adenoma obtained via open retropubic adenomectomy, with an average volume of 120.7 ml. The material obtained cut in vitro before fixation in formaldehyde. One lobe was cut using holmium laser, the other using a monopolar cutting electrode. After the incision was made, tissue mass and volume loss were evaluated. Thermocoagulation changes in the incision line were examinedunder light microscope. In the case of the holmium laser incision, the average tissue mass loss was 1.73 g, tissue volume loss 3.57 ml and the depth of thermocoagulation was 1.17 mm. When the monopolar cutting electrode was used average tissue mass loss was 0.807 g, tissue volume loss 2.48 ml and the depth of thermocoagulation was 0.19 mm. Where holmium laser was used, it was observed that the layer of tissue with thermocoagulation changes was deeper than in the case of the monopolar cutting electrode. Moreover, it was noticed that holmium laser caused bigger tissue mass and volume loss than the cutting electrode.

Long-term occupational stress is associated with regional reductions in brain tissue volumes.

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Eva Blix

Full Text Available There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM and white matter (WM volumes, and the volumes of hippocampus, caudate, and putamen - structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment.

Long-Term Occupational Stress Is Associated with Regional Reductions in Brain Tissue Volumes

Science.gov (United States)

Blix, Eva; Perski, Aleksander; Berglund, Hans; Savic, Ivanka

2013-01-01

There are increasing reports of cognitive and psychological declines related to occupational stress in subjects without psychiatric premorbidity or major life trauma. The underlying neurobiology is unknown, and many question the notion that the described disabilities represent a medical condition. Using PET we recently found that persons suffering from chronic occupational stress had limbic reductions in the 5-HT1A receptor binding potential. Here we examine whether chronic work-related stress is also associated with changes in brain structure. We performed MRI-based voxel-based morphometry and structural volumetry in stressed subjects and unstressed controls focusing on gray (GM) and white matter (WM) volumes, and the volumes of hippocampus, caudate, and putamen – structures known to be susceptible to neurotoxic changes. Stressed subjects exhibited significant reductions in the GM volumes of the anterior cingulate cortex and the dorsolateral prefrontal cortex. Furthermore, their caudate and putamen volumes were reduced, and the volumes correlated inversely to the degree of perceived stress. Our results add to previous data on chronic psychosocial stress, and indicate a morphological involvement of the frontostriatal circuits. The present findings of morphological changes in these regions confirm our previous conclusion that symptoms from occupational stress merit careful investigations and targeted treatment. PMID:23776438

Identification of radiation response genes and proteins from mouse pulmonary tissues after high-dose per fraction irradiation of limited lung volumes.

Science.gov (United States)

Jin, Hee; Jeon, Seulgi; Kang, Ga-Young; Lee, Hae-June; Cho, Jaeho; Lee, Yun-Sil

2017-02-01

The molecular effects of focal exposure of limited lung volumes to high-dose per fraction irradiation (HDFR) such as stereotactic body radiotherapy (SBRT) have not been fully characterized. In this study, we used such an irradiation system and identified the genes and proteins after HDFR to mouse lung, similar to those associated with human therapy. High focal radiation (90 Gy) was applied to a 3-mm volume of the left lung of C57BL6 mice using a small-animal stereotactic irradiator. As well as histological examination for lungs, a cDNA micro array using irradiated lung tissues and a protein array of sera were performed until 4 weeks after irradiation, and radiation-responsive genes and proteins were identified. For comparison, the long-term effects (12 months) of 20 Gy radiation wide-field dose to the left lung were also investigated. The genes ermap, epb4.2, cd200r3 (up regulation) and krt15, hoxc4, gdf2, cst9, cidec, and bnc1 (down-regulation) and the proteins of AIF, laminin, bNOS, HSP27, β-amyloid (upregulation), and calponin (downregulation) were identified as being responsive to 90 Gy HDFR. The gdf2, cst9, and cidec genes also responded to 20 Gy, suggesting that they are universal responsive genes in irradiated lungs. No universal proteins were identified in both 90 Gy and 20 Gy. Calponin, which was downregulated in protein antibody array analysis, showed a similar pattern in microarray data, suggesting a possible HDFR responsive serum biomarker that reflects gene alteration of irradiated lung tissue. These genes and proteins also responded to the lower doses of 20 Gy and 50 Gy HDFR. These results suggest that identified candidate genes and proteins are HDFR-specifically expressed in lung damage induced by HDFR relevant to SBRT in humans.

Volume of the crocodilian brain and endocast during ontogeny.

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Daniel Jirak

Full Text Available Understanding complex situations and planning difficult actions require a brain of appropriate size. Animal encephalisation provides an indirect information about these abilities. The brain is entirely composed of soft tissue and, as such, rarely fossilises. As a consequence, the brain proportions and morphology of some extinct vertebrates are usually only inferred from their neurocranial endocasts. However, because the morphological configuration of the brain is not fully reflected in the endocast, knowledge of the brain/endocast relationship is essential (especially the ratio of brain volume to endocast volume or the equivalent proportion of interstitial tissue for studying the endocasts of extinct animals. Here we assess the encephalic volume and structure of modern crocodilians. The results we obtained using ex vivo magnetic resonance imaging reveal how the endoneurocranial cavity and brain compartments of crocodilians change configuration during ontogeny. We conclude that the endocasts of adult crocodilians are elongated and expanded while their brains are more linearly organised. The highest proportion of brain tissue to endocast volume is in the prosencephalon at over 50% in all but the largest animals, whereas the proportion in other brain segments is under 50% in all but the smallest animals and embryos. Our results may enrich the field of palaeontological study by offering more precise phylogenetic interpretations of the neuroanatomic characteristics of extinct vertebrates at various ontogenetic stages.

A probabilistic approach to delineating functional brain regions

DEFF Research Database (Denmark)

Kalbitzer, Jan; Svarer, Claus; Frokjaer, Vibe G

2009-01-01

The purpose of this study was to develop a reliable observer-independent approach to delineating volumes of interest (VOIs) for functional brain regions that are not identifiable on structural MR images. The case is made for the raphe nuclei, a collection of nuclei situated in the brain stem known...... to be densely packed with serotonin transporters (5-hydroxytryptaminic [5-HTT] system). METHODS: A template set for the raphe nuclei, based on their high content of 5-HTT as visualized in parametric (11)C-labeled 3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile PET images, was created for 10...... healthy subjects. The templates were subsequently included in the region sets used in a previously published automatic MRI-based approach to create an observer- and activity-independent probabilistic VOI map. The probabilistic map approach was tested in a different group of 10 subjects and compared...

THE EFFECTS OF AN EARLY RETURN TO TRAINING ON THE BONE-TENDON JUNCTION POST-ACUTE MICRO-INJURY HEALING

Directory of Open Access Journals (Sweden)

Lin Wang

2012-06-01

Full Text Available Bone-tendon junction (BTJ overuse injuries are common athletic and occupational problems. BTJ injuries may sometimes be caused by resuming training too early after injury. To study the effects of post-injury resuming training within 48 hours on the acute injury healing process, as it is often the case for athletes. Twelve mature female rabbits were assigned to one of the following groups: acute injury (AI, n = 6, post-injury early return to training (PIERT, n = 6 and normal control (CON, n = 6. Tissue specimens were harvested at week 4. The radiological and histological characteristics of the AI and PIERT groups were compared among the groups. The trabecular thickness of the PIERT group was significantly different from those of the AI and CON group. A histological evaluation revealed poor collagen fibre alignment, extensive scar tissue and lowered cell density in the AI and PIERT groups compared with the CON group, but no significant differences were observed between the AI group and the PIERT group. The fibrocartilage zone and proteoglycan area in the PIERT group were significantly different from those in AI group. No differences were observed in the Total VOI volume (TV, Object volume (OBV, Percent object volume (BV/TV and trabecular number (Tb.N among the AI, PIERT and CON groups. In conclusion, a repeatable animal model of bone-tendon junction acute micro-damage by puncture was established. Resuming training in 48 hours did not significantly deteriorate the BTJ injury healing, but improved bone remodelling and increased fibrocartilage zone thickness

Integrating dimension reduction and out-of-sample extension in automated classification of ex vivo human patellar cartilage on phase contrast X-ray computed tomography.

Science.gov (United States)

Nagarajan, Mahesh B; Coan, Paola; Huber, Markus B; Diemoz, Paul C; Wismüller, Axel

2015-01-01

Phase contrast X-ray computed tomography (PCI-CT) has been demonstrated as a novel imaging technique that can visualize human cartilage with high spatial resolution and soft tissue contrast. Different textural approaches have been previously investigated for characterizing chondrocyte organization on PCI-CT to enable classification of healthy and osteoarthritic cartilage. However, the large size of feature sets extracted in such studies motivates an investigation into algorithmic feature reduction for computing efficient feature representations without compromising their discriminatory power. For this purpose, geometrical feature sets derived from the scaling index method (SIM) were extracted from 1392 volumes of interest (VOI) annotated on PCI-CT images of ex vivo human patellar cartilage specimens. The extracted feature sets were subject to linear and non-linear dimension reduction techniques as well as feature selection based on evaluation of mutual information criteria. The reduced feature set was subsequently used in a machine learning task with support vector regression to classify VOIs as healthy or osteoarthritic; classification performance was evaluated using the area under the receiver-operating characteristic (ROC) curve (AUC). Our results show that the classification performance achieved by 9-D SIM-derived geometric feature sets (AUC: 0.96 ± 0.02) can be maintained with 2-D representations computed from both dimension reduction and feature selection (AUC values as high as 0.97 ± 0.02). Thus, such feature reduction techniques can offer a high degree of compaction to large feature sets extracted from PCI-CT images while maintaining their ability to characterize the underlying chondrocyte patterns.

Gender-linked impact of epicardial adipose tissue volume in patients who underwent coronary artery bypass graft surgery or non-coronary valve surgery.

Directory of Open Access Journals (Sweden)

Gulinu Maimaituxun

Full Text Available Traditional and non-traditional risk factors for atherosclerotic cardiovascular disease (ASCVD are different between men and women. Gender-linked impact of epicardial adipose tissue volume (EATV in patients undergoing coronary artery bypass grafting (CABG remains unknown.Gender-linked impact of EATV, abdominal fat distribution and other traditional ASCVD risk factors were compared in 172 patients (men: 115; women: 57 who underwent CABG or non-coronary valvular surgery (non-CABG.In men, EATV, EATV index (EATV/body surface area and the markers of adiposity such as body mass index, waist circumference and visceral fat area were higher in the CABG group than in the non-CABG group. Traditional ASCVD risk factors were also prevalent in the CABG group. In women, EATV and EATV index were higher in the CABG group, but other adiposity markers were comparable between CABG and non-CABG groups. Multivariate logistic regression analysis showed that in men, CABG was determined by EATV Index and other ASCVD risk factors including hypertension, dyslipidemia, adiponectin, high sensitive C-reactive protein (hsCRP and type 2 diabetes mellitus (Corrected R2 = 0.262, p < 0.0001, while in women, type 2 diabetes mellitus is a single strong predictor for CABG, excluding EATV Index (Corrected R2 = 0.266, p = 0.005.Our study found that multiple risk factors, including epicardial adipose tissue volume and traditional ASCVD factors are determinants for CABG in men, but type 2 diabetes mellitus was the sole determinant in women. Gender-specific disparities in risk factors of CABG prompt us to evaluate new diagnostic and treatment strategies and to seek underlying mechanisms.

Digital tissue and what it may reveal about the brain.

Science.gov (United States)

Morgan, Josh L; Lichtman, Jeff W

2017-10-30

Imaging as a means of scientific data storage has evolved rapidly over the past century from hand drawings, to photography, to digital images. Only recently can sufficiently large datasets be acquired, stored, and processed such that tissue digitization can actually reveal more than direct observation of tissue. One field where this transformation is occurring is connectomics: the mapping of neural connections in large volumes of digitized brain tissue.

Differential radiosensitivity on a tissue level in Delphinium ajacis

Energy Technology Data Exchange (ETDEWEB)

Mandal, S K; Basu, R K [Bose Research Inst., Calcutta (India). Cryogenetics Lab.

1980-09-01

Root, leaf, pollen mother cell and endosperm of D.ajacis showed differential sensitivity as measured by X-ray-induced chromosomal aberrations at mitotic anaphase and telophase stages of the first and second division cycles after irradiation. These tissues differed significantly in Interphase Chromosome Volume (ICV) values. In all the tissues the percentage of aberrant cells increased linearly with increase in X-ray dose. Though endosperm had the largest ICV value it was the most radioresistant tissue tested. The relative radiosensitivity of the other 3 tissues was positively correlated with ICV value. The radioresistance of endosperm is probably due to factors unique to this tissue which remained obscure.

High tidal volume ventilation in infant mice.

Science.gov (United States)

Cannizzaro, Vincenzo; Zosky, Graeme R; Hantos, Zoltán; Turner, Debra J; Sly, Peter D

2008-06-30

Infant mice were ventilated with either high tidal volume (V(T)) with zero end-expiratory pressure (HVZ), high V(T) with positive end-expiratory pressure (PEEP) (HVP), or low V(T) with PEEP. Thoracic gas volume (TGV) was determined plethysmographically and low-frequency forced oscillations were used to measure the input impedance of the respiratory system. Inflammatory cells, total protein, and cytokines in bronchoalveolar lavage fluid (BALF) and interleukin-6 (IL-6) in serum were measured as markers of pulmonary and systemic inflammatory response, respectively. Coefficients of tissue damping and tissue elastance increased in all ventilated mice, with the largest rise seen in the HVZ group where TGV rapidly decreased. BALF protein levels increased in the HVP group, whereas serum IL-6 rose in the HVZ group. PEEP keeps the lungs open, but provides high volumes to the entire lungs and induces lung injury. Compared to studies in adult and non-neonatal rodents, infant mice demonstrate a different response to similar ventilation strategies underscoring the need for age-specific animal models.

The effect of customized beam shaping on normal tissue complications in radiation therapy of parotid gland tumors

International Nuclear Information System (INIS)

Keus, R.; Boer, R. de; Lebesque, J.; Noach, P.

1991-01-01

The impact of customized beam shaping was studied for 5 patients with parotid tumors treated with a paired wedged field technique. For each patient 2 plans were generated. The standard plan had unblocked portals with field sizes defined by the largest target contour found in any CT slice. In the 2nd plan customized beam's view (BEV) designed blocks were added to both beams. The differences in those distributions between the 2 types of plans were evaluated using dose-volume histograms (DVH). As expected, the dose distribution within the target volume showed no difference. However, a considerable sparing of normal tissue was observed for the plans with customized blocks. The volume of un-necessary exposed normal tissue that received more than 90 percent of the prescribed dose, was reduced by a factor of about 4: from 165 to 44 percent on an average, if the volume is expressed as a percentage of the target volume in each patient. In particular, the homolateral mandible showed a mean decrease of 21 percent of integral dose when blocks were used. Normal tissue complication probabilities (NTCP) were calculated. For a tumor dose of 70 Gy, the average bone necrosis probability was reduced from 8.4 percent (no blocks) to 4.1. percent (blocks). For other normal tissues such as nervous tissue, other soft tissues and bones a substantial reduction of integral dose was found for al patients when individual blocks were used. (author). 10 refs.; 4 figs.; 2 tabs

Sexual steroids in serum and prostatic tissue of human non-cancerous prostate (STERPROSER trial).

Science.gov (United States)

Neuzillet, Yann; Raynaud, Jean-Pierre; Radulescu, Camélia; Fiet, Jean; Giton, Franck; Dreyfus, Jean-François; Ghoneim, Tarek P; Lebret, Thierry; Botto, Henry

2017-11-01

The specific involvement of the sex steroids in the growth of the prostatic tissue remains unclear. Sex steroid concentrations in plasma and in fresh surgical samples of benign central prostate were correlated to prostate volume. Monocentric prospective study performed between September 2014 and January 2017. Age, obesity parameters, and both serum and intraprostatic concentrations of sex steroids were collected complying with the latest Endocrine Society guidelines and the steroids assessed by GC/MS. Statistical calculations were adjusted for age and body mass index (BMI). Thirty-two patients, equally divided between normal- and high-volume prostate groups, were included in the analysis. High-volume prostate patients were older, heavier and had higher BMI. Comparison adjusted for age and BMI showed higher DHT concentrations in high-volume prostate. Both normal- and high-volume prostate tissues concentrate sex steroids in a similar way. Comparison of enzymatic activity surrogate marker ratios within tissue highlighted similar TT/E1 and TT/E2 ratios, and higher DHT/E1 ratio and lower DHT/PSA ratio in the high-volume prostates. STERPROSER trial provides evidence for higher DHT concentration in highvolume prostates, that could reflect either higher 5-alpha reductase expression or lower expression of downstream metabolizing enzymes such as 3a-hydoxysteroid dehydrogenase. © 2017 Wiley Periodicals, Inc.

Comparative study of pulsed-continuous arterial spin labeling and dynamic susceptibility contrast imaging by histogram analysis in evaluation of glial tumors.

Science.gov (United States)

Arisawa, Atsuko; Watanabe, Yoshiyuki; Tanaka, Hisashi; Takahashi, Hiroto; Matsuo, Chisato; Fujiwara, Takuya; Fujiwara, Masahiro; Fujimoto, Yasunori; Tomiyama, Noriyuki

2018-06-01

Arterial spin labeling (ASL) is a non-invasive perfusion technique that may be an alternative to dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) for assessment of brain tumors. To our knowledge, there have been no reports on histogram analysis of ASL. The purpose of this study was to determine whether ASL is comparable with DSC-MRI in terms of differentiating high-grade and low-grade gliomas by evaluating the histogram analysis of cerebral blood flow (CBF) in the entire tumor. Thirty-four patients with pathologically proven glioma underwent ASL and DSC-MRI. High-signal areas on contrast-enhanced T 1 -weighted images or high-intensity areas on fluid-attenuated inversion recovery images were designated as the volumes of interest (VOIs). ASL-CBF, DSC-CBF, and DSC-cerebral blood volume maps were constructed and co-registered to the VOI. Perfusion histogram analyses of the whole VOI and statistical analyses were performed to compare the ASL and DSC images. There was no significant difference in the mean values for any of the histogram metrics in both of the low-grade gliomas (n = 15) and the high-grade gliomas (n = 19). Strong correlations were seen in the 75th percentile, mean, median, and standard deviation values between the ASL and DSC images. The area under the curve values tended to be greater for the DSC images than for the ASL images. DSC-MRI is superior to ASL for distinguishing high-grade from low-grade glioma. ASL could be an alternative evaluation method when DSC-MRI cannot be used, e.g., in patients with renal failure, those in whom repeated examination is required, and in children.

Tracking of adipose tissue-derived progenitor cells using two magnetic nanoparticle types

Energy Technology Data Exchange (ETDEWEB)

Kasten, Annika; Siegmund, Birte J. [Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Rostock University Medical Center, Schillingallee 35 D-18057 Rostock (Germany); Grüttner, Cordula [Micromod Partikeltechnologie GmbH, Warnemünde, D-18115 Rostock (Germany); Kühn, Jens-Peter [Department of Radiology and Neuroradiology, Greifswald University Medical Center, D-17475 Greifswald (Germany); Frerich, Bernhard, E-mail: bernhard.frerich@med.uni-rostock.de [Department of Oral and Maxillofacial Surgery, Facial Plastic Surgery, Rostock University Medical Center, Schillingallee 35 D-18057 Rostock (Germany)

2015-04-15

Magnetic resonance imaging (MRI) is to be considered as an emerging detection technique for cell tracking experiments to evaluate the fate of transplanted progenitor cells and develop successful cell therapies for tissue engineering. Adipose tissue engineering using adipose tissue-derived progenitor cells has been advocated for the cure of soft tissue defects or for persistent soft tissue augmentation. Adipose tissue-derived progenitor cells were differentiated into the adipogenic lineage and labeled with two different types of magnetic iron oxide nanoparticles in varying concentrations which resulted in a concentration-dependent reduction of gene expression of adipogenic differentiation markers, adiponectin and fatty acid-binding protein 4 (FABP4), whereas the metabolic activity was not altered. As a result, only low nanoparticle concentrations for labeling were used for in vivo experiments. Cells were seeded onto collagen scaffolds and subcutaneously implanted into severe combined immunodeficient (SCID) mice. At 24 h as well as 28 days after implantation, MRI analyses were performed visualizing nanoparticle-labeled cells using T2-weighted sequences. The quantification of absolute volume of the scaffolds revealed a decrease of volume over time in all experimental groups. The distribution of nanoparticle-labeled cells within the scaffolds varied likewise over time. - Highlights: • Adipose tissue-derived stem cells (ASC) were labeled with magnetic iron oxide nanoparticles. • Nanoparticles influenced the adipogenic differentiation of ASC. • Labeled cells were seeded onto collagen scaffolds and implanted in SCID mice. • Nanoparticle-labeled cells were visualized in vivo using T2-weighted sequences. • Volume of collagen scaffolds was decreased over time after implantation.

Tracking of adipose tissue-derived progenitor cells using two magnetic nanoparticle types

International Nuclear Information System (INIS)

Kasten, Annika; Siegmund, Birte J.; Grüttner, Cordula; Kühn, Jens-Peter; Frerich, Bernhard

2015-01-01

Magnetic resonance imaging (MRI) is to be considered as an emerging detection technique for cell tracking experiments to evaluate the fate of transplanted progenitor cells and develop successful cell therapies for tissue engineering. Adipose tissue engineering using adipose tissue-derived progenitor cells has been advocated for the cure of soft tissue defects or for persistent soft tissue augmentation. Adipose tissue-derived progenitor cells were differentiated into the adipogenic lineage and labeled with two different types of magnetic iron oxide nanoparticles in varying concentrations which resulted in a concentration-dependent reduction of gene expression of adipogenic differentiation markers, adiponectin and fatty acid-binding protein 4 (FABP4), whereas the metabolic activity was not altered. As a result, only low nanoparticle concentrations for labeling were used for in vivo experiments. Cells were seeded onto collagen scaffolds and subcutaneously implanted into severe combined immunodeficient (SCID) mice. At 24 h as well as 28 days after implantation, MRI analyses were performed visualizing nanoparticle-labeled cells using T2-weighted sequences. The quantification of absolute volume of the scaffolds revealed a decrease of volume over time in all experimental groups. The distribution of nanoparticle-labeled cells within the scaffolds varied likewise over time. - Highlights: • Adipose tissue-derived stem cells (ASC) were labeled with magnetic iron oxide nanoparticles. • Nanoparticles influenced the adipogenic differentiation of ASC. • Labeled cells were seeded onto collagen scaffolds and implanted in SCID mice. • Nanoparticle-labeled cells were visualized in vivo using T2-weighted sequences. • Volume of collagen scaffolds was decreased over time after implantation

SU-E-J-143: Short- and Near-Term Effects of Proton Therapy On Cerebral White Matter

Energy Technology Data Exchange (ETDEWEB)

Uh, J; Merchant, T; Ogg, R; Sabin, N; Hua, C [St. Jude Children' s Research Hospital, Memphis, TN (United States); Indelicato, D [University of Florida Proton Therapy Institute, Jacksonville, FL (United States)

2014-06-01

Purpose: To assess early effects of proton therapy on the structural integrity of cerebral white matter in relation to the subsequent near-term development of such effects. Methods: Sixteen children (aged 2–19 years) with craniopharyngioma underwent proton therapy of 54 Cobalt Gray Equivalent (CGE) in a prospective therapeutic trial. Diffusion tensor imaging (DTI) was performed at baseline before proton therapy and every 3 months thereafter. Tract-based spatial statics analysis of DTI data was performed to derive the fractional anisotropy (FA) and radial diffusivity (RD) in 26 volumes of interest (VOIs). The dose distributions were spatially normalized to identify VOIs prone to high doses. The longitudinal percentage changes of the FA and RD in these VOIs at 3 and 12 months from the baseline were calculated, and their relationships were evaluated. Results: The average dose was highest to the cerebral peduncle (CP), corticospinal tract (CST) in the pons, pontine crossing tract (PCT), anterior/posterior limbs of the internal capsule (ALIC/PLIC), and genu of the corpus callosum (GCC). It ranged from 33.3 GCE (GCC) to 49.7 GCE (CP). A mild but statistically significant (P<0.05) decline of FA was observed 3 months after proton therapy in all VOIs except the PLIC and ranged from −1.7% (ALIC) to −2.8% (PCT). A significant increase of RD was found in the CP (3.5%) and ALIC (2.1%). The average longitudinal change from the baseline was reduced at 12 months for most VOIs. However, the standard deviation increased, indicating that the temporal pattern varied individually. The follow-up measurements at 3 and 12 months correlated for the CP, CST, PCT, and GCC (P < 0.04). Conclusion: DTI data suggest early (3 months) effects of proton therapy on microstructures in the white matter. The subsequent follow-up indicated individual variation of the changes, which was partly implied by the early effects.

SU-G-JeP4-13: Continuous Intra-Fractional Monitoring of the Prostate Using Dynamic KV Collimation and Tube Current Modulation

Energy Technology Data Exchange (ETDEWEB)

Parsons, D [Dalhousie Unviersity, Halifax, Nova Scotia (Canada); Robar, J [Dalhousie Unviersity, Halifax, Nova Scotia (Canada); Nova Scotia Health Authority, Halifax, NS (Canada)

2016-06-15

Purpose: The focus of this work is to improve the available kV image quality for continuous intra-fraction monitoring of the prostate. This is investigated using a novel blade collimation system enabling modulated volume-of-interest (VOI) imaging of prostate fiducial markers. Methods: A four-blade dynamic kV collimator was used to track a VOI during gantry rotation. Planar image quality was investigated as a function of collimator dimension, while maintaining the same dose to isocenter, for a 22.2 cm diameter cylindrical water phantom with a 9 mm diameter bone insert. A sample prostate anatomy was defined in the planning system, including three fiducial markers within the CTV. The VOI margin around each marker was set to be 2σ of the population covariance matrix characterizing prostate motion. DRRs were used to calculate the kV attenuation for each VOI as a function of angle. The optimal marker and tube current were determined using kV attenuation. Monte Carlo simulations were used to calculate the imaging dose to the phantom and MV scatter dose to the imaging panel. Results: Preliminary measurements show an increase in CNR by a factor of 1.3 with the VOI method, when decreasing from an 6×6 to 2×2 cm{sup 2} field. Attenuation calculations show a change in kV fluence at the detector by a factor of 21.6 with fiducial optimization; resultant tube current modulation increases maximum dose by a factor of 1.4 compared to no modulation. MV scatter contribution to the kV detector changes by approximately a factor of two over a complete gantry rotation. Conclusion: The dynamic collimation system allows single fiducial marker tracking at a very low dose, with reduction of scatter and improvement of image quality, compared to imaging the entire prostate. The approach is compatible with tube current modulation, which enables consistent image quality throughout the range of gantry rotation. This project was funded by Varian Medical Systems.

Experimental evidence for negative turgor pressure in small leaf cells of Robinia pseudoacacia L versus large cells of Metasequoia glyptostroboides Hu et W.C.Cheng. 1. Evidence from pressure-volume curve analysis of dead tissue.

Science.gov (United States)

Yang, Dongmei; Pan, Shaoan; Ding, Yiting; Tyree, Melvin T

2017-03-01

This paper provides a mini-review of evidence for negative turgor pressure in leaf cells starting with experimental evidence in the late 1950s and ending with biomechanical models published in 2014. In the present study, biomechanical models were used to predict how negative turgor pressure might be manifested in dead tissue, and experiments were conducted to test the predictions. The main findings were as follows: (i) Tissues killed by heating to 60 or 80 °C or by freezing in liquid nitrogen all became equally leaky to cell sap solutes and all seemed to pass freely through the cell walls. (ii) Once cell sap solutes could freely pass the cell walls, the shape of pressure-volume curves was dramatically altered between living and dead cells. (iii) Pressure-volume curves of dead tissue seem to measure negative turgor defined as negative when inside minus outside pressure is negative. (iv) Robinia pseudoacacia leaves with small palisade cells had more negative turgor than Metasequoia glyptostroboides with large cells. (v) The absolute difference in negative turgor between R. pseudoacacia and M. glyptostroboides approached as much as 1.0 MPa in some cases. The differences in the manifestation of negative turgor in living versus dead tissue are discussed. © 2016 John Wiley & Sons Ltd.

Normal tissue complication probability (NTCP), the clinician,s perspective

International Nuclear Information System (INIS)

Yeoh, E.K.

2011-01-01

Full text: 3D radiation treatment planning has enabled dose distributions to be related to the volume of normal tissues irradiated. The dose volume histograms thus derived have been utilized to set NTCP dose constraints to facilitate optimization of treatment planning. However, it is not widely appreciated that a number of important variables other than DYH's which determine NTCP in the individual patient. These variables will be discussed under the headings of patient and treatment related as well as tumour related factors. Patient related factors include age, co-morbidities such as connective tissue disease and diabetes mellitus, previous tissue/organ damage, tissue architectural organization (parallel or serial), regional tissue/organ and individual tissue/organ radiosensitivities as well as the development of severe acute toxicity. Treatment related variables which need to be considered include dose per fraction (if not the conventional 1.8012.00 Gy/fraction, particularly for IMRT), number of fractions and total dose, dose rate (particularly if combined with brachytherapy) and concurrent chemotherapy or other biological dose modifiers. Tumour related factors which impact on NTCP include infiltration of normal tissue/organ usually at presentation leading to compromised function but also with recurrent disease after radiation therapy as well as variable tumour radiosensitivities between and within tumour types. Whilst evaluation of DYH data is a useful guide in the choice of treatment plan, the current state of knowledge requires the clinician to make an educated judgement based on a consideration of the other factors.

Ridge augmentation with soft tissue procedures in aesthetic dentistry: pre- and postoperative volume measurements with a new kind of moire technique

Science.gov (United States)

Studer, Stephan P.; Mueller, Ernst; Bucher, Alfred

1993-09-01

The aim of this paper was to measure the volume differences of operated alveolar ridge defects before and until 3 months post-surgically. Ten patients with ten localized alveolar ridge defects were operated on. Five alveolar ridge defects were corrected by using the full thickness onlay graft technique and the other five defects were operated by the subepithelial connective tissue graft technique. A strict standardized operation protocol was followed and all alveolar ridge defects were operated on by the same dental surgeon. Before as well as 1, 2, and 3 months after surgery the corrected defect was photographed and an impression was made by using an A-silicon material to produce a gypsum-cast model. The form of all these cast models was then measured using the moire technique. The three months result of ten cases shows that the form of the operated alveolar ridge defects, which were corrected by the subepithelial connective tissue graft technique are more stable compared to those which were operated on by the full thickness onlay graft technique. Localized alveolar ridge defects using the latter method does not show a form stability after 3 months post-surgically.

Microdosimetric characterisation of radiation fields for modelling tissue response in radiotherapy

Directory of Open Access Journals (Sweden)

He Wang

2014-02-01

Full Text Available Purpose: Our overall goal is the development of an approach to model tissue response to radiotherapy in which a tissue is viewed as a statistical ensemble of interacting cells. This involves characterisation of radiation fields on the spatial scale of subcellular structures. On this scale, the spatial distribution of radiation energy imparted to tissue is highly non-uniform and should be characterised in statistical terms. Microdosimetry provides a formalism developed for that purpose. This study addresses limitations of the standard microdosimetric approach to modelling tissue response by introducing two new characteristics that include additional information in a form convenient for this application.Methods: The standard microdosimetric approach is based on the concept of a sensitive volume (SV representing a target volume in the cell. It is considered in isolation from other SVs, implying that energy depositions in different SVs are statistically independent and that individual cells respond to radiation independent of each other. In this study, we examined the latter approximation through analysis of correlation functions. All calculations were performed with Geant4-DNA Monte Carlo code. Results: We found that for some realistic scenarios, spatial correlations of deposited energy can be significant. Two new characteristics of radiation fields are proposed. The first is the specific energy-volume histogram (zVH, which is a microscopic analogue of the dose-volume histogram. The second describes the probability distribution of deposited energies in two SVs without assuming statistical independence between the SVs. Numerical examples for protons and carbon ions of therapeutic energies are presented and discussed.Conclusion: We extended the microdosimetric approach to modelling tissue response by including additional important characteristics and presented them in a more conventional radiotherapy format

Tissue expansion and fluid absorption by skin tissue following intradermal injections through hollow microneedles

Science.gov (United States)

Shrestha, Pranav; Stoeber, Boris

2017-11-01

Hollow microneedles provide a promising alternative to conventional drug delivery techniques due to improved patient compliance and the dose sparing effect. The dynamics of fluid injected through hollow microneedles into skin, which is a heterogeneous and deformable porous medium, have not been investigated extensively in the past. We have introduced the use of Optical Coherence Tomography (OCT) for real-time visualization of fluid injections into excised porcine tissue. The results from ex-vivo experiments, including cross-sectional tissue images from OCT and pressure/flow-rate measurements, show a transient mode of high flow-rate into the tissue followed by a lower steady-state infusion rate. The injected fluid expands the underlying tissue and causes the external free surface of the skin to rise, forming a characteristic intradermal wheal. We have used OCT to visualize the evolution of tissue and free surface deformation, and advancement of the boundary between regions of expanding and stationary tissue. We will show the effect of different injection parameters such as fluid pressure, viscosity and microneedle retraction on the injected volume. This work has been supported through funding from the Collaborative Health Research Program by the Natural Science and Engineering Research Council of Canada and the Canadian Health Research Institute, and through the Canada Research Chairs program.

Volume arc therapy of gynaecological tumours: target volume coverage improvement without dose increase for critical organs; Arctherapie volumique des tumeurs gynecologiques: amelioration de la couverture du volume cible sans augmentation de la dose aux organes critiques

Energy Technology Data Exchange (ETDEWEB)

Ducteil, A.; Kerr, C.; Idri, K.; Fenoglietto, P.; Vieillot, S.; Ailleres, N.; Dubois, J.B.; Azria, D. [CRLC Val-d' Aurelle, Montpellier (France)

2011-10-15

The authors report the assessment of the application of conventional intensity-modulated conformational radiotherapy (IMRT) and volume arc-therapy (RapidArc) for the treatment of cervical cancers, with respect to conventional radiotherapy. Dosimetric plans associated with each of these techniques have been compared. Dose-volume histograms of these three plans have also been compared for the previsional target volume (PTV), organs at risk, and sane tissue. IMCT techniques are equivalent in terms of sparing of organs at risk, and improve target volume coverage with respect to conventional radiotherapy. Arc-therapy reduces significantly treatment duration. Short communication

The fractionation of adipose tissue procedure to obtain stromal vascular fractions for regenerative purposes

NARCIS (Netherlands)

van Dongen, Joris A.; Stevens, Hieronymus P.; Parvizi, Mojtaba; van der Lei, Berend; Harmsen, Martin C.

2016-01-01

Autologous adipose tissue transplantation is clinically used to reduce dermal scarring and to restore volume loss. The therapeutic benefit on tissue damage more likely depends on the stromal vascular fraction of adipose tissue than on the adipocyte fraction. This stromal vascular fraction can be

Semi-automated segmentation of a glioblastoma multiforme on brain MR images for radiotherapy planning.

Science.gov (United States)

Hori, Daisuke; Katsuragawa, Shigehiko; Murakami, Ryuuji; Hirai, Toshinori

2010-04-20

We propose a computerized method for semi-automated segmentation of the gross tumor volume (GTV) of a glioblastoma multiforme (GBM) on brain MR images for radiotherapy planning (RTP). Three-dimensional (3D) MR images of 28 cases with a GBM were used in this study. First, a sphere volume of interest (VOI) including the GBM was selected by clicking a part of the GBM region in the 3D image. Then, the sphere VOI was transformed to a two-dimensional (2D) image by use of a spiral-scanning technique. We employed active contour models (ACM) to delineate an optimal outline of the GBM in the transformed 2D image. After inverse transform of the optimal outline to the 3D space, a morphological filter was applied to smooth the shape of the 3D segmented region. For evaluation of our computerized method, we compared the computer output with manually segmented regions, which were obtained by a therapeutic radiologist using a manual tracking method. In evaluating our segmentation method, we employed the Jaccard similarity coefficient (JSC) and the true segmentation coefficient (TSC) in volumes between the computer output and the manually segmented region. The mean and standard deviation of JSC and TSC were 74.2+/-9.8% and 84.1+/-7.1%, respectively. Our segmentation method provided a relatively accurate outline for GBM and would be useful for radiotherapy planning.

Comparison of manual and automated quantification methods of 123I-ADAM

International Nuclear Information System (INIS)

Kauppinen, T.; Keski-Rahkonen, A.; Sihvola, E.; Helsinki Univ. Central Hospital

2005-01-01

123 I-ADAM is a novel radioligand for imaging of the brain serotonin transporters (SERTs). Traditionally, the analysis of brain receptor studies has been based on observer-dependent manual region of interest definitions and visual interpretation. Our aim was to create a template for automated image registrations and volume of interest (VOI) quantification and to show that an automated quantification method of 123 I-ADAM is more repeatable than the manual method. Patients, methods: A template and a predefined VOI map was created from 123 I-ADAM scans done for healthy volunteers (n=15). Scans of another group of healthy persons (HS, n=12) and patients with bulimia nervosa (BN, n=10) were automatically fitted to the template and specific binding ratios (SBRs) were calculated by using the VOI map. Manual VOI definitions were done for the HS and BN groups by both one and two observers. The repeatability of the automated method was evaluated by using the BN group. Results: For the manual method, the interobserver coefficient of repeatability was 0.61 for the HS group and 1.00 for the BN group. The intra-observer coefficient of repeatability for the BN group was 0.70. For the automated method, the coefficient of repeatability was 0.13 for SBRs in midbrain. Conclusion: An automated quantification gives valuable information in addition to visual interpretation decreasing also the total image handling time and giving clear advantages for research work. An automated method for analysing 123 I-ADAM binding to the brain SERT gives repeatable results for fitting the studies to the template and for calculating SBRs, and could therefore replace manual methods. (orig.)

Comparison of manual and automated quantification methods of {sup 123}I-ADAM

Energy Technology Data Exchange (ETDEWEB)

Kauppinen, T. [Helsinki Univ. Central Hospital (Finland). HUS Helsinki Medical Imaging Center; Helsinki Univ. Central Hospital (Finland). Division of Nuclear Medicine; Koskela, A.; Ahonen, A. [Helsinki Univ. Central Hospital (Finland). Division of Nuclear Medicine; Diemling, M. [Hermes Medical Solutions, Stockholm (Sweden); Keski-Rahkonen, A.; Sihvola, E. [Helsinki Univ. (Finland). Dept. of Public Health; Helsinki Univ. Central Hospital (Finland). Dept. of Psychiatry

2005-07-01

{sup 123}I-ADAM is a novel radioligand for imaging of the brain serotonin transporters (SERTs). Traditionally, the analysis of brain receptor studies has been based on observer-dependent manual region of interest definitions and visual interpretation. Our aim was to create a template for automated image registrations and volume of interest (VOI) quantification and to show that an automated quantification method of {sup 123}I-ADAM is more repeatable than the manual method. Patients, methods: A template and a predefined VOI map was created from {sup 123}I-ADAM scans done for healthy volunteers (n=15). Scans of another group of healthy persons (HS, n=12) and patients with bulimia nervosa (BN, n=10) were automatically fitted to the template and specific binding ratios (SBRs) were calculated by using the VOI map. Manual VOI definitions were done for the HS and BN groups by both one and two observers. The repeatability of the automated method was evaluated by using the BN group. Results: For the manual method, the interobserver coefficient of repeatability was 0.61 for the HS group and 1.00 for the BN group. The intra-observer coefficient of repeatability for the BN group was 0.70. For the automated method, the coefficient of repeatability was 0.13 for SBRs in midbrain. Conclusion: An automated quantification gives valuable information in addition to visual interpretation decreasing also the total image handling time and giving clear advantages for research work. An automated method for analysing {sup 123}I-ADAM binding to the brain SERT gives repeatable results for fitting the studies to the template and for calculating SBRs, and could therefore replace manual methods. (orig.)

Cone beam computed tomography for diagnosis of bisphosphonate-related osteonecrosis of the jaw: evaluation of quantitative and qualitative image parameters

International Nuclear Information System (INIS)

Guggenberger, Roman; Koral, Emrah; Andreisek, Gustav; Zemann, Wolfgang; Jacobsen, Christine; Metzler, Philipp

2014-01-01

To assess the diagnostic performance of quantitative and qualitative image parameters in cone-beam computed tomography (CBCT) for diagnosis of bisphosphonate-related osteonecrosis of the jaw (BRONJ). A BRONJ (22 patients, mean age 70.0 years) group was age and gender matched to a healthy control group (22 patients, mean age 68.0 years). On CBCT images two independent readers performed quantitative bone density value (BDV) measurements with region and volume-of-interest (ROI and VOI) based approaches and qualitative scoring of BRONJ-associated necrosis, sclerosis and periosteal thickening (1 = not present to 5 = definitely present). Intraoperative and clinical findings served as standard of reference. Interreader agreements and diagnostic performance were assessed by intraclass correlation coefficients (ICC), kappa-statistics and receiver-operating characteristic (ROC) analysis. Twenty-three regions in 22 patients were affected by BRONJ. ICC values for mean BDV VOI and mean BDV ROI were 0.864 and 0.968, respectively (p < 0.001). The area under the curve (AUC) for mean BDV VOI and mean BDV ROI was 0.58/0.83 with a sensitivity of 57/83 % and specificity of 61/77 % for diagnosis of BRONJ, respectively. Kappa values for presence of necrosis, sclerosis and periosteal thickening were 0.575, 0.617 and 0.885, respectively. AUC values for qualitative parameters ranged between 0.90-0.96 with sensitivity of 96 % and specificities between 79-96 % at respective cutoff scores. BRONJ can be effectively diagnosed with CBCT. Qualitative image parameters yield a higher diagnostic performance than quantitative parameters, and ROI-based attenuation measurements were more accurate than VOI-based measurements. (orig.)

PET/MRI of metabolic activity in osteoarthritis: A feasibility study.

Science.gov (United States)

Kogan, Feliks; Fan, Audrey P; McWalter, Emily J; Oei, Edwin H G; Quon, Andrew; Gold, Garry E

2017-06-01

To evaluate positron emission tomography / magnetic resonance imaging (PET/MRI) knee imaging to detect and characterize osseous metabolic abnormalities and correlate PET radiotracer uptake with osseous abnormalities and cartilage degeneration observed on MRI. Both knees of 22 subjects with knee pain or injury were scanned at one timepoint, without gadolinium, on a hybrid 3.0T PET-MRI system following injection of 18 F-fluoride or 18 F-fluorodeoxyglucose (FDG). A musculoskeletal radiologist identified volumes of interest (VOIs) around bone abnormalities on MR images and scored bone marrow lesions (BMLs) and osteophytes using a MOAKS scoring system. Cartilage appearance adjacent to bone abnormalities was graded with MRI-modified Outerbridge classifications. On PET standardized uptake values (SUV) maps, VOIs with SUV greater than 5 times the SUV in normal-appearing bone were identified as high-uptake VOI (VOI High ). Differences in 18 F-fluoride uptake between bone abnormalities, BML, and osteophyte grades and adjacent cartilage grades on MRI were identified using Mann-Whitney U-tests. SUV max in all subchondral bone lesions (BML, osteophytes, sclerosis) was significantly higher than that of normal-appearing bone on MRI (P subchondral bone on MRI. Furthermore, many small grade 1 osteophytes (40 of 82 [49%]), often described as the earliest signs of osteoarthritis (OA), did not show high uptake. Lastly, PET SUV max in subchondral bone adjacent to grade 0 cartilage was significantly lower compared to that of grades 1-2 (P subchondral bone, which appear normal on MRI. 2 Technical Efficacy: Stage 1 J. MAGN. RESON. IMAGING 2017;45:1736-1745. © 2016 International Society for Magnetic Resonance in Medicine.

Evaluation of laser radiation regimes at thermal tissue destruction

Science.gov (United States)

Ivanov, Anatoly; Kazaryan, Mishik A.; Molodykh, E. I.; Shchetinkina, T. A.

1996-01-01

The existing methods of laser destruction of biotissues, widely spread in surgery and coagulation action, are based on local heat emission in the tissues after light absorption. Here we present the results of the simulation of tissues heat destruction, taking into account the influence of blood and lymph circulation on the processes of heat transfer. The problem is adapted to the case of liver tissue with tumor. A liver is considered as a capillary-porous body with internal blood circulation. Heatconductivity and tissue-blood heat transfer are considered. Heat action is assumed to be implemented with contact laser scalpel. The mathematical model consists of two inhomogeneous nonlinear equations of heatconductivity with spherical symmetry. Nonstationary temperature fields of tissue and blood are determined and the main parameters are: (1) coefficients of heatconductivity and capacitance of blood and tissue, (2) blood and tissue density, (3) total metabolic energy, (4) volume coefficient accounting for heat-exchange between tissue and blood, and (5) blood circulation velocity. The power of laser radiation was taken into account in boundary conditions set for the center of coagulated tissue volume. We also took into account the process connected with changing of substance phase (vaporization). The original computer programs allow one to solve the problem varying in a wide range of the main parameters. Reasonable agreement was found between the calculation results and the experimental data for operations on microsamples and on test animals. It was demonstrated, in particular, that liver tissue coagulation regime is achieved at 10 W laser power during 25 s. The coagulation radius of 0.7 cm with the given tumor radius of 0.5 cm corresponds to the real clinical situation in case of metastasis liver affection.

Systematic evaluation of three different commercial software solutions for automatic segmentation for adaptive therapy in head-and-neck, prostate and pleural cancer

International Nuclear Information System (INIS)

La Macchia, Mariangela; Fellin, Francesco; Amichetti, Maurizio; Cianchetti, Marco; Gianolini, Stefano; Paola, Vitali; Lomax, Antony J; Widesott, Lamberto

2012-01-01

To validate, in the context of adaptive radiotherapy, three commercial software solutions for atlas-based segmentation. Fifteen patients, five for each group, with cancer of the Head&Neck, pleura, and prostate were enrolled in the study. In addition to the treatment planning CT (pCT) images, one replanning CT (rCT) image set was acquired for each patient during the RT course. Three experienced physicians outlined on the pCT and rCT all the volumes of interest (VOIs). We used three software solutions (VelocityAI 2.6.2 (V), MIM 5.1.1 (M) by MIMVista and ABAS 2.0 (A) by CMS-Elekta) to generate the automatic contouring on the repeated CT. All the VOIs obtained with automatic contouring (AC) were successively corrected manually. We recorded the time needed for: 1) ex novo ROIs definition on rCT; 2) generation of AC by the three software solutions; 3) manual correction of AC. To compare the quality of the volumes obtained automatically by the software and manually corrected with those drawn from scratch on rCT, we used the following indexes: overlap coefficient (DICE), sensitivity, inclusiveness index, difference in volume, and displacement differences on three axes (x, y, z) from the isocenter. The time saved by the three software solutions for all the sites, compared to the manual contouring from scratch, is statistically significant and similar for all the three software solutions. The time saved for each site are as follows: about an hour for Head&Neck, about 40 minutes for prostate, and about 20 minutes for mesothelioma. The best DICE similarity coefficient index was obtained with the manual correction for: A (contours for prostate), A and M (contours for H&N), and M (contours for mesothelioma). From a clinical point of view, the automated contouring workflow was shown to be significantly shorter than the manual contouring process, even though manual correction of the VOIs is always needed

Systematic evaluation of three different commercial software solutions for automatic segmentation for adaptive therapy in head-and-neck, prostate and pleural cancer.

Science.gov (United States)

La Macchia, Mariangela; Fellin, Francesco; Amichetti, Maurizio; Cianchetti, Marco; Gianolini, Stefano; Paola, Vitali; Lomax, Antony J; Widesott, Lamberto

2012-09-18

To validate, in the context of adaptive radiotherapy, three commercial software solutions for atlas-based segmentation. Fifteen patients, five for each group, with cancer of the Head&Neck, pleura, and prostate were enrolled in the study. In addition to the treatment planning CT (pCT) images, one replanning CT (rCT) image set was acquired for each patient during the RT course. Three experienced physicians outlined on the pCT and rCT all the volumes of interest (VOIs). We used three software solutions (VelocityAI 2.6.2 (V), MIM 5.1.1 (M) by MIMVista and ABAS 2.0 (A) by CMS-Elekta) to generate the automatic contouring on the repeated CT. All the VOIs obtained with automatic contouring (AC) were successively corrected manually. We recorded the time needed for: 1) ex novo ROIs definition on rCT; 2) generation of AC by the three software solutions; 3) manual correction of AC.To compare the quality of the volumes obtained automatically by the software and manually corrected with those drawn from scratch on rCT, we used the following indexes: overlap coefficient (DICE), sensitivity, inclusiveness index, difference in volume, and displacement differences on three axes (x, y, z) from the isocenter. The time saved by the three software solutions for all the sites, compared to the manual contouring from scratch, is statistically significant and similar for all the three software solutions. The time saved for each site are as follows: about an hour for Head&Neck, about 40 minutes for prostate, and about 20 minutes for mesothelioma. The best DICE similarity coefficient index was obtained with the manual correction for: A (contours for prostate), A and M (contours for H&N), and M (contours for mesothelioma). From a clinical point of view, the automated contouring workflow was shown to be significantly shorter than the manual contouring process, even though manual correction of the VOIs is always needed.

Systematic evaluation of three different commercial software solutions for automatic segmentation for adaptive therapy in head-and-neck, prostate and pleural cancer

Directory of Open Access Journals (Sweden)

La Macchia Mariangela

2012-09-01

Full Text Available Abstract Purpose To validate, in the context of adaptive radiotherapy, three commercial software solutions for atlas-based segmentation. Methods and materials Fifteen patients, five for each group, with cancer of the Head&Neck, pleura, and prostate were enrolled in the study. In addition to the treatment planning CT (pCT images, one replanning CT (rCT image set was acquired for each patient during the RT course. Three experienced physicians outlined on the pCT and rCT all the volumes of interest (VOIs. We used three software solutions (VelocityAI 2.6.2 (V, MIM 5.1.1 (M by MIMVista and ABAS 2.0 (A by CMS-Elekta to generate the automatic contouring on the repeated CT. All the VOIs obtained with automatic contouring (AC were successively corrected manually. We recorded the time needed for: 1 ex novo ROIs definition on rCT; 2 generation of AC by the three software solutions; 3 manual correction of AC. To compare the quality of the volumes obtained automatically by the software and manually corrected with those drawn from scratch on rCT, we used the following indexes: overlap coefficient (DICE, sensitivity, inclusiveness index, difference in volume, and displacement differences on three axes (x, y, z from the isocenter. Results The time saved by the three software solutions for all the sites, compared to the manual contouring from scratch, is statistically significant and similar for all the three software solutions. The time saved for each site are as follows: about an hour for Head&Neck, about 40 minutes for prostate, and about 20 minutes for mesothelioma. The best DICE similarity coefficient index was obtained with the manual correction for: A (contours for prostate, A and M (contours for H&N, and M (contours for mesothelioma. Conclusions From a clinical point of view, the automated contouring workflow was shown to be significantly shorter than the manual contouring process, even though manual correction of the VOIs is always needed.

Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields.

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Fei Xie

Full Text Available Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart.We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium ("penetrating needles" configuration and one circular electrode each on epi- and endocardium, opposing each other ("epi-endo" configuration.For thick tissues (10 mm and moderate anisotropy ratio (a = 2, we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10 leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria and higher anisotropy ratio (a = 10, the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist.These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the fiber orientation is not consistent

Effect of Twisted Fiber Anisotropy in Cardiac Tissue on Ablation with Pulsed Electric Fields.

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Xie, Fei; Zemlin, Christian W

2016-01-01

Ablation of cardiac tissue with pulsed electric fields is a promising alternative to current thermal ablation methods, and it critically depends on the electric field distribution in the heart. We developed a model that incorporates the twisted anisotropy of cardiac tissue and computed the electric field distribution in the tissue. We also performed experiments in rabbit ventricles to validate our model. We find that the model agrees well with the experimentally determined ablation volume if we assume that all tissue that is exposed to a field greater than 3 kV/cm is ablated. In our numerical analysis, we considered how tissue thickness, degree of anisotropy, and electrode configuration affect the geometry of the ablated volume. We considered two electrode configurations: two parallel needles inserted into the myocardium ("penetrating needles" configuration) and one circular electrode each on epi- and endocardium, opposing each other ("epi-endo" configuration). For thick tissues (10 mm) and moderate anisotropy ratio (a = 2), we find that the geometry of the ablated volume is almost unaffected by twisted anisotropy, i.e. it is approximately translationally symmetric from epi- to endocardium, for both electrode configurations. Higher anisotropy ratio (a = 10) leads to substantial variation in ablation width across the wall; these variations were more pronounced for the penetrating needle configuration than for the epi-endo configuration. For thinner tissues (4 mm, typical for human atria) and higher anisotropy ratio (a = 10), the epi-endo configuration yielded approximately translationally symmetric ablation volumes, while the penetrating electrodes configuration was much more sensitive to fiber twist. These results suggest that the epi-endo configuration will be reliable for ablation of atrial fibrillation, independently of fiber orientation, while the penetrating electrode configuration may experience problems when the fiber orientation is not consistent across the

Metamaterial-based transmit and receive system for whole-body magnetic resonance imaging at ultra-high magnetic fields.

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Herrmann, Tim; Liebig, Thorsten; Mallow, Johannes; Bruns, Christian; Stadler, Jörg; Mylius, Judith; Brosch, Michael; Svedja, Jan Taro; Chen, Zhichao; Rennings, Andreas; Scheich, Henning; Plaumann, Markus; Hauser, Marcus J B; Bernarding, Johannes; Erni, Daniel

2018-01-01

Magnetic resonance imaging (MRI) at ultra-high fields (UHF), such as 7 T, provides an enhanced signal-to-noise ratio and has led to unprecedented high-resolution anatomic images and brain activation maps. Although a variety of radio frequency (RF) coil architectures have been developed for imaging at UHF conditions, they usually are specialized for small volumes of interests (VoI). So far, whole-body coil resonators are not available for commercial UHF human whole-body MRI systems. The goal of the present study was the development and validation of a transmit and receive system for large VoIs that operates at a 7 T human whole-body MRI system. A Metamaterial Ring Antenna System (MRAS) consisting of several ring antennas was developed, since it allows for the imaging of extended VoIs. Furthermore, the MRAS not only requires lower intensities of the irradiated RF energy, but also provides a more confined and focused injection of excitation energy on selected body parts. The MRAS consisted of several antennas with 50 cm inner diameter, 10 cm width and 0.5 cm depth. The position of the rings was freely adjustable. Conformal resonant right-/left-handed metamaterial was used for each ring antenna with two quadrature feeding ports for RF power. The system was successfully implemented and demonstrated with both a silicone oil and a water-NaCl-isopropanol phantom as well as in vivo by acquiring whole-body images of a crab-eating macaque. The potential for future neuroimaging applications was demonstrated by the acquired high-resolution anatomic images of the macaque's head. Phantom and in vivo measurements of crab-eating macaques provided high-resolution images with large VoIs up to 40 cm in xy-direction and 45 cm in z-direction. The results of this work demonstrate the feasibility of the MRAS system for UHF MRI as proof of principle. The MRAS shows a substantial potential for MR imaging of larger volumes at 7 T UHF. This new technique may provide new diagnostic potential

Local respiratory motion correction for PET/CT imaging: Application to lung cancer

Energy Technology Data Exchange (ETDEWEB)

Lamare, F., E-mail: frederic.lamare@chu-bordeaux.fr; Fernandez, P. [INCIA, UMR 5287, University of Bordeaux, Talence F-33400, France and Nuclear Medicine Department, University Hospital, Bordeaux 33000 (France); Fayad, H.; Visvikis, D. [INSERM, UMR1101, LaTIM, Université de Bretagne Occidentale, Brest 29609 (France)

2015-10-15

Purpose: Despite multiple methodologies already proposed to correct respiratory motion in the whole PET imaging field of view (FOV), such approaches have not found wide acceptance in clinical routine. An alternative can be the local respiratory motion correction (LRMC) of data corresponding to a given volume of interest (VOI: organ or tumor). Advantages of LRMC include the use of a simple motion model, faster execution times, and organ specific motion correction. The purpose of this study was to evaluate the performance of LMRC using various motion models for oncology (lung lesion) applications. Methods: Both simulated (NURBS based 4D cardiac-torso phantom) and clinical studies (six patients) were used in the evaluation of the proposed LRMC approach. PET data were acquired in list-mode and synchronized with respiration. The implemented approach consists first in defining a VOI on the reconstructed motion average image. Gated PET images of the VOI are subsequently reconstructed using only lines of response passing through the selected VOI and are used in combination with a center of gravity or an affine/elastic registration algorithm to derive the transformation maps corresponding to the respiration effects. Those are finally integrated in the reconstruction process to produce a motion free image over the lesion regions. Results: Although the center of gravity or affine algorithm achieved similar performance for individual lesion motion correction, the elastic model, applied either locally or to the whole FOV, led to an overall superior performance. The spatial tumor location was altered by 89% and 81% for the elastic model applied locally or to the whole FOV, respectively (compared to 44% and 39% for the center of gravity and affine models, respectively). This resulted in similar associated overall tumor volume changes of 84% and 80%, respectively (compared to 75% and 71% for the center of gravity and affine models, respectively). The application of the nonrigid

Using deep learning to segment breast and fibroglandular tissue in MRI volumes.

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Dalmış, Mehmet Ufuk; Litjens, Geert; Holland, Katharina; Setio, Arnaud; Mann, Ritse; Karssemeijer, Nico; Gubern-Mérida, Albert

2017-02-01

Automated segmentation of breast and fibroglandular tissue (FGT) is required for various computer-aided applications of breast MRI. Traditional image analysis and computer vision techniques, such atlas, template matching, or, edge and surface detection, have been applied to solve this task. However, applicability of these methods is usually limited by the characteristics of the images used in the study datasets, while breast MRI varies with respect to the different MRI protocols used, in addition to the variability in breast shapes. All this variability, in addition to various MRI artifacts, makes it a challenging task to develop a robust breast and FGT segmentation method using traditional approaches. Therefore, in this study, we investigated the use of a deep-learning approach known as "U-net." We used a dataset of 66 breast MRI's randomly selected from our scientific archive, which includes five different MRI acquisition protocols and breasts from four breast density categories in a balanced distribution. To prepare reference segmentations, we manually segmented breast and FGT for all images using an in-house developed workstation. We experimented with the application of U-net in two different ways for breast and FGT segmentation. In the first method, following the same pipeline used in traditional approaches, we trained two consecutive (2C) U-nets: first for segmenting the breast in the whole MRI volume and the second for segmenting FGT inside the segmented breast. In the second method, we used a single 3-class (3C) U-net, which performs both tasks simultaneously by segmenting the volume into three regions: nonbreast, fat inside the breast, and FGT inside the breast. For comparison, we applied two existing and published methods to our dataset: an atlas-based method and a sheetness-based method. We used Dice Similarity Coefficient (DSC) to measure the performances of the automated methods, with respect to the manual segmentations. Additionally, we computed

Mechanically robust cryogels with injectability and bioprinting supportability for adipose tissue engineering.

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Qi, Dianjun; Wu, Shaohua; Kuss, Mitchell A; Shi, Wen; Chung, Soonkyu; Deegan, Paul T; Kamenskiy, Alexey; He, Yini; Duan, Bin

2018-05-26

Bioengineered adipose tissues have gained increased interest as a promising alternative to autologous tissue flaps and synthetic adipose fillers for soft tissue augmentation and defect reconstruction in clinic. Although many scaffolding materials and biofabrication methods have been investigated for adipose tissue engineering in the last decades, there are still challenges to recapitulate the appropriate adipose tissue microenvironment, maintain volume stability, and induce vascularization to achieve long-term function and integration. In the present research, we fabricated cryogels consisting of methacrylated gelatin, methacrylated hyaluronic acid, and 4arm poly(ethylene glycol) acrylate (PEG-4A) by using cryopolymerization. The cryogels were repeatedly injectable and stretchable, and the addition of PEG-4A improved the robustness and mechanical properties. The cryogels supported human adipose progenitor cell (HWA) and adipose derived mesenchymal stromal cell adhesion, proliferation, and adipogenic differentiation and maturation, regardless of the addition of PEG-4A. The HWA laden cryogels facilitated the co-culture of human umbilical vein endothelial cells (HUVEC) and capillary-like network formation, which in return also promoted adipogenesis. We further combined cryogels with 3D bioprinting to generate handleable adipose constructs with clinically relevant size. 3D bioprinting enabled the deposition of multiple bioinks onto the cryogels. The bioprinted flap-like constructs had an integrated structure without delamination and supported vascularization. Adipose tissue engineering is promising for reconstruction of soft tissue defects, and also challenging for restoring and maintaining soft tissue volume and shape, and achieving vascularization and integration. In this study, we fabricated cryogels with mechanical robustness, injectability, and stretchability by using cryopolymerization. The cryogels promoted cell adhesion, proliferation, and adipogenic

Blood flow and blood volume in a transplanted rat fibrosarcoma

International Nuclear Information System (INIS)

Tozer, G.M.; Morris, C.C.

1990-01-01

Blood flow measurements following i.v. infusion of iodi-antipyrine labelled with 14 C ( 14 C-IAP) and blood volume measurements following i.v. injection of 125 I human serum albumin and 51 Cr-labelled red blood cells were made in a transplanted rat fibrosarcoma for comparison with various normal tissues. The tumour-blood partition co-efficient for 14 C-IAP w as found to be 0.79 ± 0.07 which is similar to most of the normal tissues studied. The solubility of 14 C-IAP in plasma was found to be higher than that in whole blood. Blood flow to tumours 3 was found to be 17.9 ± 4.0 ml blood 100 g tissue -1 xmin -1 . These values were considered to be primarily measurements of nutritive flow. Blood in the tumours was found to occupy around 1% of the tissue space which was similar to that found for normal muscle and skin. There was no direct correlation between % blood volume and blood flow for the different tissues studied. Th haematocrit of blood contained in tumour tissue was calculated to be significantly lower than that of blood contained in the normal tissues. It was suspected that permeability of tumour blood vessel walls to 125 I-HSA could have accounted for this difference. (author). 41 refs.; 2 figs.; 3 tabs

Correlation of biological aggressiveness assessed by 11C-methionine PET and hypoxic burden assessed by 18F-fluoromisonidazole PET in newly diagnosed glioblastoma

International Nuclear Information System (INIS)

Kawai, Nobuyuki; Miyake, Keisuke; Okada, Masaki; Tamiya, Takashi; Maeda, Yukito; Yamamoto, Yuka; Nishiyama, Yoshihiro; Kudomi, Nobuyuki

2011-01-01

Glioblastoma multiforme (GBM) is characterized by tissue hypoxia associated with resistance to radiotherapy and chemotherapy. To clarify the biological link between hypoxia and tumour-induced neovascularization and tumour aggressiveness, we analysed detailed volumetric and spatial information of viable hypoxic tissue assessed by 18 F-fluoromisonidazole (FMISO) PET relative to neovascularization in Gd-enhanced MRI and tumour aggressiveness by L-methyl- 11 C-methionine (MET) PET in newly diagnosed GBMs. Ten patients with newly diagnosed GBMs were investigated with FMISO PET, MET PET and Gd-enhanced MRI before surgery. Tumour volumes were calculated by performing a three-dimensional threshold-based volume of interest (VOI) analysis for metabolically active volume on MET PET (MET uptake indices of ≥1.3 and ≥1.5) and Gd-enhanced volume on MRI. FMISO PET was scaled to the blood FMISO activity to create tumour to blood (T/B) images. The hypoxic volume (HV) was defined as the region with T/B greater than 1.2. PET and MR images of each patient were coregistered to analyse the spatial location of viable hypoxic tissue relative to neovascularization and active tumour extension. Metabolically active tumour volumes defined using MET uptake indices of ≥1.3 and ≥1.5 and the volumes of Gd enhancement showed a strong correlation (r = 0.86, p < 0.01 for an index of ≥1.3 and r = 0.77, p < 0.05 for an index of ≥1.5). The HVs were also excellently correlated with the volumes of Gd enhancement (r = 0.94, p < 0.01). The metabolically active tumour volumes as defined by a MET uptake index of ≥1.3 and the HVs exhibited a strong correlation (r = 0.87, p < 0.01). On superimposed images, the metabolically active area on MET PET defined by a MET uptake index of ≥1.3 was usually larger than the area of the Gd enhancement and about 20-30% of the MET area extended outside the area of the enhancement. On the other hand, the surface area of viable hypoxic tissue with a T/B cutoff of

Review of soft tissue augmentation in the face

Directory of Open Access Journals (Sweden)

James Newman

2009-08-01

Full Text Available James NewmanFacial Plastic Surgery, Stanford University Medical Center, Palo Alto, CAFacial Plastic Surgery, Stanford University Medical Center, Palo Alto, CA, USAAbstract: A primary pillar of facial rejuvenation is the replacement of soft tissue atrophy via a variety of augmentation techniques. The techniques can be classified into three categories, skeletal onlay grafts, subcutaneous volumizers, and dermal fillers. While onlay grafts and subcutaneous volumizers have the most persistent results, the emergence of improved dermal fillers in the past 5 years has become increasingly popular. An accurate diagnosis of the level(s of soft tissue atrophy in the face needs to be made prior to selection of the category or combination of techniques. In the younger patient, the selection of a dermal filler or combination of fillers can be adequate for treatment. A comparison of the composition and characteristics of the available dermal fillers are discussed in detail to assist the clinician in understanding the actual mechanism of soft tissue augmentation. In the more advanced aging face, a combination of the three categories may be necessary to produce optimal results. Just as dermal fillers have become more differentiated to increase their longevity, the non-injectible long-lasting implants are becoming more developed to mimic accurate viscoelastic properties of the facial soft tissues. All three classes of augmentation techniques can provide patients with very satisfactory results as part of overall facial rejuvenation.Keywords: soft tissue, dermal fillers, facial implants, facial augmentation

Hemodynamic parameters change earlier than tissue oxygen tension in hemorrhage.

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Pestel, Gunther J; Fukui, Kimiko; Kimberger, Oliver; Hager, Helmut; Kurz, Andrea; Hiltebrand, Luzius B

2010-05-15

Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after preparation, baseline measurements were taken. At first, 5% of total blood volume was withdrawn, followed by another 5% increment, and then in 10% increments until death. After withdrawal of 5% of estimated blood volume, dPP increased from 6.1% +/- 3.0% to 20.8% +/- 2.7% (P < 0.01). Mean arterial pressure (MAP), mean pulmonary artery pressure (PAP) and pulmonary artery occlusion pressure (PAOP) decreased with a blood loss of 10% (P < 0.01). Cardiac output (CO) changed after a blood loss of 20% (P < 0.05). Tissue oxygen tension in central organs, and blood flow in the jejunal muscularis decreased (P < 0.05) after a blood loss of 20%. Tissue oxygen tension in the skin, and jejunal mucosa blood flow decreased (P < 0.05) after a blood loss of 40% and 50%, respectively. In this hemorrhagic pig model systemic hemodynamic parameters were more sensitive to detect acute hypovolemia than tissue oxygen tension measurements or jejunal LDF measurements. Acute blood loss was detected first by dPP. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Imaging the spectral reflectance properties of bipolar radiofrequency-fused bowel tissue

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Clancy, Neil T.; Arya, Shobhit; Stoyanov, Danail; Du, Xiaofei; Hanna, George B.; Elson, Daniel S.

2015-07-01

Delivery of radiofrequency (RF) electrical energy is used during surgery to heat and seal tissue, such as vessels, allowing resection without blood loss. Recent work has suggested that this approach may be extended to allow surgical attachment of larger tissue segments for applications such as bowel anastomosis. In a large series of porcine surgical procedures bipolar RF energy was used to resect and re-seal the small bowel in vivo with a commercial tissue fusion device (Ligasure; Covidien PLC, USA). The tissue was then imaged with a multispectral imaging laparoscope to obtain a spectral datacube comprising both fused and healthy tissue. Maps of blood volume, oxygen saturation and scattering power were derived from the measured reflectance spectra using an optimised light-tissue interaction model. A 60% increase in reflectance of visible light (460-700 nm) was observed after fusion, with the tissue taking on a white appearance. Despite this the distinctive shape of the haemoglobin absorption spectrum was still noticeable in the 460-600 nm wavelength range. Scattering power increased in the fused region in comparison to normal serosa, while blood volume and oxygen saturation decreased. Observed fusion-induced changes in the reflectance spectrum are consistent with the biophysical changes induced through tissue denaturation and increased collagen cross-linking. The multispectral imager allows mapping of the spatial extent of these changes and classification of the zone of damaged tissue. Further analysis of the spectral data in parallel with histopathological examination of excised specimens will allow correlation of the optical property changes with microscopic alterations in tissue structure.

Cell swelling and volume regulation

DEFF Research Database (Denmark)

Hoffmann, Else Kay

1992-01-01

The extracellular space in the brain is typically 20% of the tissue volume and is reduced to at least half its size under conditions of neural insult. Whether there is a minimum size to the extracellular space was discussed. A general model for cell volume regulation was presented, followed...... by a discussion on how many of the generally involved mechanisms are identified in neural cells and (or) in astrocytes. There seems to be clear evidence suggesting that parallel K+ and Cl- channels mediate regulatory volume decrease in primary cultures of astrocytes, and a stretch-activated cation channel has...... been reported. The role of the different channels was discussed. A taurine leak pathway is clearly activated after cell swelling both in astrocytes and in neurones. The relations between the effect of glutamate and cell swelling were discussed. Discussion on the clearance of potassium from...

Limitations of intraoperative adrenal remnant volume measurement in patients undergoing subtotal adrenalectomy.

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Brauckhoff, Michael; Stock, Karsten; Stock, Susanne; Lorenz, Kerstin; Sekulla, Carsten; Brauckhoff, Katrin; Thanh, Phuong Nguyen; Gimm, Oliver; Spielmann, Rolf Peter; Dralle, Henning

2008-05-01

Recent studies have shown that a minimum of approximately one-third of one normal adrenal gland is required for sufficient adrenocortical stress capacity. Correlation between intraoperative measurement, determination of remnant size by computed tomography (CT), and adrenocortical stress capacity has not been examined so far. Twenty-two patients with familial pheochromocytoma (n=13), sporadic pheochromocytoma (n=3), and adrenocortical tumors (n=6) who underwent unilateral or bilateral subtotal adrenalectomy (STAE, 28 adrenal remnants) were prospectively studied. Patients were examined in a multi-slice CT to determine residual adrenal tissue and by ACTH test 4 days and 3 months postoperatively. There was a slight significant correlation between intraoperative and CT calculated volumes (r=0.77; pSTAE has limitations. CT gives larger volumes compared with intraoperative determination. For calculation of a volume-function correlation of residual adrenal tissue, in clinical practice, the determination of relative adrenal residual volume is acceptable.

Lower subcortical gray matter volume in both younger smokers and established smokers relative to non-smokers

Science.gov (United States)

Hanlon, Colleen A.; Owens, Max M.; Joseph, Jane E.; Zhu, Xun; George, Mark S.; Brady, Kathleen T.; Hartwell, Karen J.

2014-01-01

Although established adult smokers with long histories of nicotine dependence have lower neural tissue volume than non-smokers, it is not clear if lower regional brain volume is also observed in younger, less established smokers. The primary goal of this study was to investigate neural tissue volume in a large group of smokers and non-smokers, with a secondary goal of measuring the impact of age on these effects. We used voxel-based morphometry to compare regional gray matter volume in 118 individuals (59 smokers, 59 age- and gender-matched non-smokers). Younger smokers had significantly lower gray matter volume in the left thalamus and the left amygdala than their non-smoking peers (family-wise error-corrected clusters, P smokers. Established smokers had significantly lower gray matter volume than age-matched non-smokers in the insula, parahippocampal gyrus and pallidum. Medial prefrontal cortex gray matter volume was negatively correlated with pack-years of smoking among the established smokers, but not the younger smokers. These data reveal that regional tissue volume differences are not limited exclusively to established smokers. Deficits in young adults indicate that cigarette smoking may either be deleterious to the thalamus and amygdala at an earlier age than previously reported, or that pre-existing differences in these areas may predispose individuals to the development of nicotine dependence. PMID:25125263

Menstrual variation of breast volume and T2 relaxation times in cyclical mastalgia

International Nuclear Information System (INIS)

Hussain, Zainab; Brooks, Jonathan; Percy, Dave

2008-01-01

Purpose: Hormonal activity causes breast volume to change during the menstrual cycle. One possible cause of this volume change is thought to be due to water retention or oedema within the tissues. We used magnetic resonance imaging (MRI) to study the variation in breast volume and 1 H Magnetic Resonance Spectroscopy (MRS) to measure T 2 relaxation times which are known to increase with increasing tissue water content. We hypothesised that an increase in breast volume will elevate T 2 relaxation due to the presence of an increased water content within the breast. T 2 Relaxation time and volume were studied in fifteen control subjects and in a cohort of eight patients with cyclical mastalgia in order to determine whether changes in breast volume and T 2 relaxation times differed in controls and patients during menses, ovulation and premenses. Method: Breast volume was determined by the Cavalieri method in combination with point counting techniques on MR images and T 2 relaxation times of the water and fat in a voxel of breast tissue were obtained using 1 H Magnetic Resonance Spectroscopy (MRS). Results: Statistical analysis (ANOVA) demonstrated highly significant differences in breast volume between the three stages of the cycle (p 2 of fat or water did not depend on stage of cycle. T-tests demonstrated no significant differences in T 2 of water or fat between patient and control groups. The average T 2 relaxation time of water was lowest in the patient and control groups during ovulation and highest in the patient group during premenses. Conclusion: We have performed the first combined volumetric and spectroscopic study of women with cyclical mastalgia and demonstrated that the global changes in volumes and T 2 were not significantly different from normal menstrual variations

Tissue Functioning and Remodeling in the Circulatory and Ventilatory Systems

CERN Document Server

Thiriet, Marc

2013-01-01

The volumes in this authoritative series present a multidisciplinary approach to modeling and simulation of flows in the cardiovascular and ventilatory systems, especially multiscale modeling and coupled simulations. Volume 5 is devoted to cells, tissues, and organs of the cardiovascular and ventilatory systems with an emphasis on mechanotransduction-based regulation of flow. The blood vessel wall is a living tissue that quickly reacts to loads applied on it by the flowing blood. In any segment of a blood vessel, the endothelial and smooth muscle cells can sense unusual time variations in small-magnitude wall shear stress and large-amplitude wall stretch generated by abnormal hemodynamic stresses. These cells respond with a short-time scale (from seconds to hours) to adapt the vessel caliber. Since such adaptive cell activities can be described using mathematical models, a key objective of this volume is to identify the mesoscopic agents and nanoscopic mediators required to derive adequate mathematical models...

Review article: volume expansion in patients with cirrhosis

DEFF Research Database (Denmark)

Henriksen, Jens Henrik; Kiszka-Kanowitz, Marianne; Bendtsen, Flemming

2002-01-01

Adequate size and distribution of the circulating medium are important for cardiovascular function, tissue oxygenation, and fluid homoeostasis. Patients with cirrhosis have cardiovascular dysfunction with a hyperkinetic systemic circulation, abnormal distribution of the blood volume, vasodilation...

Ouabain-Induced Cytoplasmic Vesicles and Their Role in Cell Volume Maintenance

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M. A. Russo

2015-01-01

Full Text Available Cellular swelling is controlled by an active mechanism of cell volume regulation driven by a Na+/K+-dependent ATPase and by aquaporins which translocate water along the osmotic gradient. Na+/K+-pump may be blocked by ouabain, a digitalic derivative, by inhibition of ATP, or by drastic ion alterations of extracellular fluid. However, it has been observed that some tissues are still able to control their volume despite the presence of ouabain, suggesting the existence of other mechanisms of cell volume control. In 1977, by correlating electron microscopy observation with ion and water composition of liver slices incubated in different metabolic conditions in the presence or absence of ouabain, we observed that hepatocytes were able to control their volume extruding water and recovering ion composition in the presence of ouabain. In particular, hepatocytes were able to sequester ions and water in intracellular vesicles and then secrete them at the bile canaliculus pole. We named this “vesicular mechanism of cell volume control.” Afterward, this mechanism has been confirmed by us and other laboratories in several mammalian tissues. This review summarizes evidences regarding this mechanism, problems that are still pending, and questions that need to be answered. Finally, we shortly review the importance of cell volume control in some human pathological conditions.

Inter- and intra-observer variation in soft-tissue sarcoma target definition.

Science.gov (United States)

Roberge, D; Skamene, T; Turcotte, R E; Powell, T; Saran, N; Freeman, C

2011-08-01

To evaluate inter- and intra-observer variability in gross tumor volume definition for adult limb/trunk soft tissue sarcomas. Imaging studies of 15 patients previously treated with preoperative radiation were used in this study. Five physicians (radiation oncologists, orthopedic surgeons and a musculoskeletal radiologist) were asked to contour each of the 15 tumors on T1-weighted, gadolinium-enhanced magnetic resonance images. These contours were drawn twice by each physician. The volume and center of mass coordinates for each gross tumor volume were extracted and a Boolean analysis was performed to measure the degree of volume overlap. The median standard deviation in gross tumor volumes across observers was 6.1% of the average volume (range: 1.8%-24.9%). There was remarkably little variation in the 3D position of the gross tumor volume center of mass. For the 15 patients, the standard deviation of the 3D distance between centers of mass ranged from 0.06 mm to 1.7 mm (median 0.1mm). Boolean analysis demonstrated that 53% to 90% of the gross tumor volume was common to all observers (median overlap: 79%). The standard deviation in gross tumor volumes on repeat contouring was 4.8% (range: 0.1-14.4%) with a standard deviation change in the position of the center of mass of 0.4mm (range: 0mm-2.6mm) and a median overlap of 93% (range: 73%-98%). Although significant inter-observer differences were seen in gross tumor volume definition of adult soft-tissue sarcoma, the center of mass of these volumes was remarkably consistent. Variations in volume definition did not correlate with tumor size. Radiation oncologists should not hesitate to review their contours with a colleague (surgeon, radiologist or fellow radiation oncologist) to ensure that they are not outliers in sarcoma gross tumor volume definition. Protocols should take into account variations in volume definition when considering tighter clinical target volumes. Copyright © 2011 Société française de radioth

Single exponential decay waveform; a synergistic combination of electroporation and electrolysis (E2 for tissue ablation

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Nina Klein

2017-04-01

Full Text Available Background Electrolytic ablation and electroporation based ablation are minimally invasive, non-thermal surgical technologies that employ electrical currents and electric fields to ablate undesirable cells in a volume of tissue. In this study, we explore the attributes of a new tissue ablation technology that simultaneously delivers a synergistic combination of electroporation and electrolysis (E2. Method A new device that delivers a controlled dose of electroporation field and electrolysis currents in the form of a single exponential decay waveform (EDW was applied to the pig liver, and the effect of various parameters on the extent of tissue ablation was examined with histology. Results Histological analysis shows that E2 delivered as EDW can produce tissue ablation in volumes of clinical significance, using electrical and temporal parameters which, if used in electroporation or electrolysis separately, cannot ablate the tissue. Discussion The E2 combination has advantages over the three basic technologies of non-thermal ablation: electrolytic ablation, electrochemical ablation (reversible electroporation with injection of drugs and irreversible electroporation. E2 ablates clinically relevant volumes of tissue in a shorter period of time than electrolysis and electroporation, without the need to inject drugs as in reversible electroporation or use paralyzing anesthesia as in irreversible electroporation.

A multi-atlas based method for automated anatomical rat brain MRI segmentation and extraction of PET activity.

Science.gov (United States)

Lancelot, Sophie; Roche, Roxane; Slimen, Afifa; Bouillot, Caroline; Levigoureux, Elise; Langlois, Jean-Baptiste; Zimmer, Luc; Costes, Nicolas

2014-01-01

Preclinical in vivo imaging requires precise and reproducible delineation of brain structures. Manual segmentation is time consuming and operator dependent. Automated segmentation as usually performed via single atlas registration fails to account for anatomo-physiological variability. We present, evaluate, and make available a multi-atlas approach for automatically segmenting rat brain MRI and extracting PET activies. High-resolution 7T 2DT2 MR images of 12 Sprague-Dawley rat brains were manually segmented into 27-VOI label volumes using detailed protocols. Automated methods were developed with 7/12 atlas datasets, i.e. the MRIs and their associated label volumes. MRIs were registered to a common space, where an MRI template and a maximum probability atlas were created. Three automated methods were tested: 1/registering individual MRIs to the template, and using a single atlas (SA), 2/using the maximum probability atlas (MP), and 3/registering the MRIs from the multi-atlas dataset to an individual MRI, propagating the label volumes and fusing them in individual MRI space (propagation & fusion, PF). Evaluation was performed on the five remaining rats which additionally underwent [18F]FDG PET. Automated and manual segmentations were compared for morphometric performance (assessed by comparing volume bias and Dice overlap index) and functional performance (evaluated by comparing extracted PET measures). Only the SA method showed volume bias. Dice indices were significantly different between methods (PF>MP>SA). PET regional measures were more accurate with multi-atlas methods than with SA method. Multi-atlas methods outperform SA for automated anatomical brain segmentation and PET measure's extraction. They perform comparably to manual segmentation for FDG-PET quantification. Multi-atlas methods are suitable for rapid reproducible VOI analyses.

The characteristics of cortical glucose metabolism in amblyopia

Energy Technology Data Exchange (ETDEWEB)

Ahn, Ji Young [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of); Lee, Dong Soo; Chung, June Key; Shin, Seung Ai; Lee, Myung Chul [College of Medicine, Ewha Womans Univ., Seoul (Korea, Republic of)

2000-07-01

Cortical metabolism of amblyopia patients was investigated with F-18-FDG PET and Statistical Parametric Mapping (SPM) and quantificiation based on volume of interest (VOI) by statistical probabilistic anatomical map (SPAM). In 9 amblyopic patients (12{+-}7 years ) and 20 normal subjects (23{+-}2 years), F-18-FDG PET scans were peformed in amblyopic patients after amblyopic eye or sound eye was patch-closed during PET studies. SPM was done with SPM96. By multiplying SPAM to FDG images, counts of 98 VOI's were calculated and compared with 3 S. D. range of those of normal subjects. On SPM, cortical metabolism decreased (p<0.05) in occipital lobe (Ba 17, 18, 19), superior partietal lobe (Ba 7), and inferior temporal lobe (BA 37, 20). FDG uptake of gyri of occuipital lobe was decreased in 2 and increased in 2, and was normal in the other 5. FDG uptake of gyri of parietal, frontal, and temporal lobes were decreased in FDG uptake on these VOIs. We conclude that cortical metabolism in occipital lobe and extraoccipital lobes was variable but was consistent regardless of visual input during PET studies in amblyopic patients. SPM and quantification of functional images using SPAM could reveal subtle differences or changes according to visual input. The significance of metabolic changes of extraoccipital lobes should be studies further.

The characteristics of cortical glucose metabolism in amblyopia

International Nuclear Information System (INIS)

Ahn, Ji Young; Lee, Dong Soo; Chung, June Key; Shin, Seung Ai; Lee, Myung Chul

2000-01-01

Cortical metabolism of amblyopia patients was investigated with F-18-FDG PET and Statistical Parametric Mapping (SPM) and quantificiation based on volume of interest (VOI) by statistical probabilistic anatomical map (SPAM). In 9 amblyopic patients (12±7 years ) and 20 normal subjects (23±2 years), F-18-FDG PET scans were peformed in amblyopic patients after amblyopic eye or sound eye was patch-closed during PET studies. SPM was done with SPM96. By multiplying SPAM to FDG images, counts of 98 VOI's were calculated and compared with 3 S. D. range of those of normal subjects. On SPM, cortical metabolism decreased (p<0.05) in occipital lobe (Ba 17, 18, 19), superior partietal lobe (Ba 7), and inferior temporal lobe (BA 37, 20). FDG uptake of gyri of occuipital lobe was decreased in 2 and increased in 2, and was normal in the other 5. FDG uptake of gyri of parietal, frontal, and temporal lobes were decreased in FDG uptake on these VOIs. We conclude that cortical metabolism in occipital lobe and extraoccipital lobes was variable but was consistent regardless of visual input during PET studies in amblyopic patients. SPM and quantification of functional images using SPAM could reveal subtle differences or changes according to visual input. The significance of metabolic changes of extraoccipital lobes should be studies further

Local stem cell depletion model for normal tissue damage

International Nuclear Information System (INIS)

Yaes, R.J.; Keland, A.

1987-01-01

The hypothesis that radiation causes normal tissue damage by completely depleting local regions of tissue of viable stem cells leads to a simple mathematical model for such damage. In organs like skin and spinal cord where destruction of a small volume of tissue leads to a clinically apparent complication, the complication probability is expressed as a function of dose, volume and stem cell number by a simple triple negative exponential function analogous to the double exponential function of Munro and Gilbert for tumor control. The steep dose response curves for radiation myelitis that are obtained with our model are compared with the experimental data for radiation myelitis in laboratory rats. The model can be generalized to include other types or organs, high LET radiation, fractionated courses of radiation, and cases where an organ with a heterogeneous stem cell population receives an inhomogeneous dose of radiation. In principle it would thus be possible to determine the probability of tumor control and of damage to any organ within the radiation field if the dose distribution in three dimensional space within a patient is known

Sampling Strategies and Processing of Biobank Tissue Samples from Porcine Biomedical Models.

Science.gov (United States)

Blutke, Andreas; Wanke, Rüdiger

2018-03-06

In translational medical research, porcine models have steadily become more popular. Considering the high value of individual animals, particularly of genetically modified pig models, and the often-limited number of available animals of these models, establishment of (biobank) collections of adequately processed tissue samples suited for a broad spectrum of subsequent analyses methods, including analyses not specified at the time point of sampling, represent meaningful approaches to take full advantage of the translational value of the model. With respect to the peculiarities of porcine anatomy, comprehensive guidelines have recently been established for standardized generation of representative, high-quality samples from different porcine organs and tissues. These guidelines are essential prerequisites for the reproducibility of results and their comparability between different studies and investigators. The recording of basic data, such as organ weights and volumes, the determination of the sampling locations and of the numbers of tissue samples to be generated, as well as their orientation, size, processing and trimming directions, are relevant factors determining the generalizability and usability of the specimen for molecular, qualitative, and quantitative morphological analyses. Here, an illustrative, practical, step-by-step demonstration of the most important techniques for generation of representative, multi-purpose biobank specimen from porcine tissues is presented. The methods described here include determination of organ/tissue volumes and densities, the application of a volume-weighted systematic random sampling procedure for parenchymal organs by point-counting, determination of the extent of tissue shrinkage related to histological embedding of samples, and generation of randomly oriented samples for quantitative stereological analyses, such as isotropic uniform random (IUR) sections generated by the "Orientator" and "Isector" methods, and vertical

Multiplexed Dosing Assays by Digitally Definable Hydrogel Volumes

DEFF Research Database (Denmark)

Faralli, Adele; Melander, Fredrik; Larsen, Esben Kjær Unmack

2016-01-01

Stable and low-cost multiplexed drug sensitivity assays using small volumes of cells or tissue are in demand for personalized medicine, including patientspecific combination chemotherapy. Spatially defined projected light photopolymerization of hydrogels with embedded active compounds is introduc...

Dose-volume histograms for optimization of treatment plans illustrated by the example of oesophagus carcinoma

International Nuclear Information System (INIS)

Roth, J.; Huenig, R.; Huegli, C.

1995-01-01

Using the example of oesophagus carcinoma, dose-volume histograms for diverse treatment techniques are calculated and judged by means of multiplanar isodose representations. The selected treatment plans are ranked with the aid of the dose-volume histograms. We distinguish the tissue inside and outside of the target volume. The description of the spatial dose distribution in dependence of the different volumes and the respective fractions of the tumor dose therein with the help of dose-volume histograms brings about a correlation between the physical parameters and the biological effects. In addition one has to bear in mind the consequences of measures that influence the reaction and the side-effects of radiotherapy (e.g. chemotherapy), i.e. the recuperation of the tissues that were irradiated intentionally or inevitably. Taking all that into account it is evident that the dose-volume histograms are a powerful tool for assessing the quality of treatment plans. (orig./MG) [de

First experience with early dynamic 18F-NaF-PET/CT in patients with chronic osteomyelitis

International Nuclear Information System (INIS)

Freesmeyer, M.; Stecker, F.F.; Schierz, J.-H.; Winkens, T.; Hofmann, G.O.

2014-01-01

This study investigates whether early dynamic positron emission tomography/computed tomography (ed-PET/CT) using 18 F-sodium fluoride-( 18 F-NaF) is feasible in depicting early phases of radiotracer distribution in patients with chronic osteomyelitis (COM). A total of 12 ed 18 F-NaF-PET/CT examinations were performed on 11 consecutive patients (2 female, 9 male; age 53 ± 12 years) in list mode over 5 min starting with radiopharmaceutical injection before standard late 18 F-NaF-PET/CT. Eight consecutive time intervals (frames) were reconstructed for each patient: four 15 s, then four 60 s. Several volumes of interest (VOI) were selected, representing the affected area as well as different reference areas within the bone and soft tissue. Maximum and mean ed standardized uptake values (edSUV max , edSUV mean , respectively) were calculated in each VOI during each frame to measure early fluoride influx and accumulation. Results were compared between affected and non-affected (contralateral) bones. Starting in the 31-45 s frame, the affected bone area showed significantly higher edSUV max and edSUV mean compared to the healthy contralateral region. The affected bone areas also significantly differed from non-affected contralateral regions in conventional late 18 F-NaF-PET/CT. This pilot study suggests that, in patients with COM, ed 18 F-NaF-PET offers additional information about early radiotracer distribution to standard 18 F-NaF-PET/CT, similar to a three-phase bone scan. The results should be validated in larger trials which directly compare ed 18 F-NaF-PET to a three-phase bone scan. (author)

Partial volume effect in MRI

International Nuclear Information System (INIS)

Maeda, Munehiro; Yoshiya, Kazuhiko; Suzuki, Eiji

1989-01-01

According to the direction and the thickness of the imaging slice in tomography, the border between the tissues becomes unclear (partial volume effect). In the present MRI experiment, we examined border area between fat and water components using phantom in order to investigate the partial volume effect in MRI. In spin echo sequences, the intensity of the border area showed a linear relationship with composition of fat and water. Whereas, in inversion recovery and field echo sequences, we found the parameters to produce an extremely low intensity area at the border region between fat and water. This low intensity area was explained by cancellation of NMR signals from fat and water due to the difference in the direction of magnetic vectors. Clinically, partial volume effect can cause of mis-evaluation of walls, small nodules, tumor capsules and the tumor invasion in the use of inversion recovery and field echo sequences. (author)

Cement stress predictions after anatomic total shoulder arthroplasty are correlated with preoperative glenoid bone quality.

Science.gov (United States)

Terrier, Alexandre; Obrist, Raphaël; Becce, Fabio; Farron, Alain

2017-09-01

We hypothesized that biomechanical parameters typically associated with glenoid implant failure after anatomic total shoulder arthroplasty (aTSA) would be correlated with preoperative glenoid bone quality. We developed an objective automated method to quantify preoperative glenoid bone quality in different volumes of interest (VOIs): cortical bone, subchondral cortical plate, subchondral bone after reaming, subchondral trabecular bone, and successive layers of trabecular bone. Average computed tomography (CT) numbers (in Hounsfield units [HU]) were measured in each VOI from preoperative CT scans. In parallel, we built patient-specific finite element models of simulated aTSAs to predict cement stress, bone-cement interfacial stress, and bone strain around the glenoid implant. CT measurements and finite element predictions were obtained for 20 patients undergoing aTSA for primary glenohumeral osteoarthritis. We tested all linear correlations between preoperative patient characteristics (age, sex, height, weight, glenoid bone quality) and biomechanical predictions (cement stress, bone-cement interfacial stress, bone strain). Average CT numbers gradually decreased from cortical (717 HU) to subchondral and trabecular (362 HU) bone. Peak cement stress (4-10 MPa) was located within the keel hole, above the keel, or behind the glenoid implant backside. Cement stress, bone-cement interfacial stress, and bone strain were strongly negatively correlated with preoperative glenoid bone quality, particularly in VOIs behind the implant backside (subchondral trabecular bone) but also in deeper trabecular VOIs. Our numerical study suggests that preoperative glenoid bone quality is an important parameter to consider in aTSA, which may be associated with aseptic loosening of the glenoid implant. These initial results should now be confronted with clinical and radiologic outcomes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc

Mechanical tension as a driver of connective tissue growth in vitro.

Science.gov (United States)

Wilson, Cameron J; Pearcy, Mark J; Epari, Devakara R

2014-07-01

We propose the progressive mechanical expansion of cell-derived tissue analogues as a novel, growth-based approach to in vitro tissue engineering. The prevailing approach to producing tissue in vitro is to culture cells in an exogenous "scaffold" that provides a basic structure and mechanical support. This necessarily pre-defines the final size of the implantable material, and specific signals must be provided to stimulate appropriate cell growth, differentiation and matrix formation. In contrast, surgical skin expansion, driven by increments of stretch, produces increasing quantities of tissue without trauma or inflammation. This suggests that connective tissue cells have the innate ability to produce growth in response to elevated tension. We posit that this capacity is maintained in vitro, and that order-of-magnitude growth may be similarly attained in self-assembling cultures of cells and their own extracellular matrix. The hypothesis that growth of connective tissue analogues can be induced by mechanical expansion in vitro may be divided into three components: (1) tension stimulates cell proliferation and extracellular matrix synthesis; (2) the corresponding volume increase will relax the tension imparted by a fixed displacement; (3) the repeated application of static stretch will produce sustained growth and a tissue structure adapted to the tensile loading. Connective tissues exist in a state of residual tension, which is actively maintained by resident cells such as fibroblasts. Studies in vitro and in vivo have demonstrated that cellular survival, reproduction, and matrix synthesis and degradation are regulated by the mechanical environment. Order-of-magnitude increases in both bone and skin volume have been achieved clinically through staged expansion protocols, demonstrating that tension-driven growth can be sustained over prolonged periods. Furthermore, cell-derived tissue analogues have demonstrated mechanically advantageous structural adaptation in

MR signal-fat-fraction analysis and T2* weighted imaging measure BAT reliably on humans without cold exposure.

Science.gov (United States)

Holstila, Milja; Pesola, Marko; Saari, Teemu; Koskensalo, Kalle; Raiko, Juho; Borra, Ronald J H; Nuutila, Pirjo; Parkkola, Riitta; Virtanen, Kirsi A

2017-05-01

Brown adipose tissue (BAT) is compositionally distinct from white adipose tissue (WAT) in terms of triglyceride and water content. In adult humans, the most significant BAT depot is localized in the supraclavicular area. Our aim is to differentiate brown adipose tissue from white adipose tissue using fat T2* relaxation time mapping and signal-fat-fraction (SFF) analysis based on a commercially available modified 2-point-Dixon (mDixon) water-fat separation method. We hypothesize that magnetic resonance (MR) imaging can reliably measure BAT regardless of the cold-induced metabolic activation, with BAT having a significantly higher water and iron content compared to WAT. The supraclavicular area of 13 volunteers was studied on 3T PET-MRI scanner using T2* relaxation time and SFF mapping both during cold exposure and at ambient temperature; and 18 F-FDG PET during cold exposure. Volumes of interest (VOIs) were defined semiautomatically in the supraclavicular fat depot, subcutaneous WAT and muscle. The supraclavicular fat depot (assumed to contain BAT) had a significantly lower SFF and fat T2* relaxation time compared to subcutaneous WAT. Cold exposure did not significantly affect MR-based measurements. SFF and T2* values measured during cold exposure and at ambient temperature correlated inversely with the glucose uptake measured by 18 F-FDG PET. Human BAT can be reliably and safely assessed using MRI without cold activation and PET-related radiation exposure. Copyright © 2017 Elsevier Inc. All rights reserved.

Tissue concentrations of prostate-specific antigen in prostatic carcinoma and benign prostatic hyperplasia.

Science.gov (United States)

Pretlow, T G; Pretlow, T P; Yang, B; Kaetzel, C S; Delmoro, C M; Kamis, S M; Bodner, D R; Kursh, E; Resnick, M I; Bradley, E L

1991-11-11

Prostate-specific antigen (PSA), as measured in peripheral blood, is currently the most widely used marker for the assessment of tumor burden in the longitudinal study of patients with carcinoma of the prostate (PCA). Studies from other laboratories have led to the conclusion that a given volume of PCA causes a much higher level of PSA in the peripheral circulation of patients than a similar volume of prostate without carcinoma. We have evaluated PSA in the resected tissues immunohistochemically and in extracts of PCA and of prostates resected because of benign prostatic hyperplasia (BPH) with an enzyme-linked immunosorbent assay. Immunohistochemical results were less quantitative than but consistent with the results of the ELISA of tissue extracts. Immunohistochemically, there was considerable heterogeneity in the expression of PSA by both PCA and BPH both within and among prostatic tissues from different patients. While the levels of expression of PSA in these tissues overlap broadly, PSA is expressed at a lower level in PCA than in BPH when PSA is expressed as a function of wet weight of tissue (p = 0.0095), wet weight of tissue/% epithelium (p less than 0.0001), protein extracted from the tissue (p = 0.0039), or protein extracted/% epithelium (p less than 0.0001).

MRS of normal and impaired fetal brain development

International Nuclear Information System (INIS)

Girard, Nadine; Fogliarini, Celine; Viola, Angele; Confort-Gouny, Sylviane; Le Fur, Yann; Viout, Patrick; Chapon, Frederique; Levrier, Olivier; Cozzone, Patrick

2006-01-01

Cerebral maturation in the human fetal brain was investigated by in utero localized proton magnetic resonance spectroscopy (MRS). Spectra were acquired on a clinical MR system operating at 1.5 T. Body phased array coils (four coils) were used in combination with spinal coils (two coils). The size of the nominal volume of interest (VOI) was 4.5 cm 3 (20 mm x 15 mm x 15 mm). The MRS acquisitions were performed using a spin echo sequence at short and long echo times (TE = 30 ms and 135 ms) with a VOI located within the cerebral hemisphere at the level of the centrum semiovale. A significant reduction in myo-inositol and choline and an increase in N-acetylaspartate were observed with progressive age. The normal MR spectroscopy data reported here will help to determine whether brain metabolism is altered, especially when subtle anatomic changes are observed on conventional images. Some examples of impaired fetal brain development studied by MRS are illustrated

MRS of normal and impaired fetal brain development

Energy Technology Data Exchange (ETDEWEB)

Girard, Nadine [Service de Neuroradiologie, Assistance Publique-Hopitaux de Marseille, Hopital la Timone, Universite de la Mediterranee, Marseille (France)]. E-mail: nadine.girard@ap-hm.fr; Fogliarini, Celine [Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Universite de la Mediterranee, Faculte de Medecine la Timone, Marseille (France); Viola, Angele [Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Universite de la Mediterranee, Faculte de Medecine la Timone, Marseille (France); Confort-Gouny, Sylviane [Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Universite de la Mediterranee, Faculte de Medecine la Timone, Marseille (France); Le Fur, Yann [Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Universite de la Mediterranee, Faculte de Medecine la Timone, Marseille (France); Viout, Patrick [Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Universite de la Mediterranee, Faculte de Medecine la Timone, Marseille (France); Chapon, Frederique [Service de Neuroradiologie, Assistance Publique-Hopitaux de Marseille, Hopital la Timone, Universite de la Mediterranee, Marseille (France); Levrier, Olivier [Service de Neuroradiologie, Assistance Publique-Hopitaux de Marseille, Hopital la Timone, Universite de la Mediterranee, Marseille (France); Cozzone, Patrick [Centre de Resonance Magnetique Biologique et Medicale, UMR CNRS 6612, Universite de la Mediterranee, Faculte de Medecine la Timone, Marseille (France)

2006-02-15

Cerebral maturation in the human fetal brain was investigated by in utero localized proton magnetic resonance spectroscopy (MRS). Spectra were acquired on a clinical MR system operating at 1.5 T. Body phased array coils (four coils) were used in combination with spinal coils (two coils). The size of the nominal volume of interest (VOI) was 4.5 cm{sup 3} (20 mm x 15 mm x 15 mm). The MRS acquisitions were performed using a spin echo sequence at short and long echo times (TE = 30 ms and 135 ms) with a VOI located within the cerebral hemisphere at the level of the centrum semiovale. A significant reduction in myo-inositol and choline and an increase in N-acetylaspartate were observed with progressive age. The normal MR spectroscopy data reported here will help to determine whether brain metabolism is altered, especially when subtle anatomic changes are observed on conventional images. Some examples of impaired fetal brain development studied by MRS are illustrated.

Non-invasive quantitation of phosphorus metabolites in human brain and brain tumors by magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Naruse, Shoji; Higuchi, Toshihiro; Horikawa, Yoshiharu; Tanaka, Chuzo; Roth, K.; Hubesch, B.; Meyerhoff, D.J.; Weiner, M.W.

1989-01-01

In obtaining localized magnetic resonance spectra in the clinical setting, the exact determination of volume of interest (VOI), the relative sensitivity of detection within the VOI, the inhomogeneity of B 1 field, the Q factor of the coil, and saturation factors should be considered. Taking these items into account, a quantitative method for calculating the absolute amount of phosphorus metabolites was developed. Using this method, phosphorus metabolites in the brain were determined in 15 patients with brain tumors - meningioma (8) and astrocytoma (7), and 10 normal volunteers. The integrals for metabolite signals were determined by using the curve-fitting software. The concentrations for ATP, PCr, PDE, inorganic orthophosphate (Pi), and phosphomonosters (PME) were 2.5, 4.9, 11.3, 1.9 and 3.9 mM, respectively, in the normal brain. For the brain tumors, phosphorus metabolites were decreased, except for Pi and PME. These results encourage the clinical use of this method in the quantitative analysis of metabolites of the diseased brain. (Namekawa, K)

Analysis of laser surgery in non-melanoma skin cancer for optimal tissue removal

International Nuclear Information System (INIS)

Fanjul-Vélez, Félix; Salas-García, Irene; Luis Arce-Diego, José

2015-01-01

Laser surgery is a commonly used technique for tissue ablation or the resection of malignant tumors. It presents advantages over conventional non-optical ablation techniques, like a scalpel or electrosurgery, such as the increased precision of the resected volume, minimization of scars and shorter recovery periods. Laser surgery is employed in medical branches such as ophthalmology or dermatology. The application of laser surgery requires the optimal adjustment of laser beam parameters, taking into account the particular patient and lesion. In this work we present a predictive tool for tissue resection in biological tissue after laser surgery, which allows an a priori knowledge of the tissue ablation volume, area and depth. The model employs a Monte Carlo 3D approach for optical propagation and a rate equation for plasma-induced ablation. The tool takes into account characteristics of the specific lesion to be ablated, mainly the geometric, optical and ablation properties. It also considers the parameters of the laser beam, such as the radius, spatial profile, pulse width, total delivered energy or wavelength. The predictive tool is applied to dermatology tumor resection, particularly to different types of non-melanoma skin cancer tumors: basocellular carcinoma, squamous cell carcinoma and infiltrative carcinoma. The ablation volume, area and depth are calculated for healthy skin and for each type of tumor as a function of the laser beam parameters. The tool could be used for laser surgery planning before the clinical application. The laser parameters could be adjusted for optimal resection volume, by personalizing the process to the particular patient and lesion. (paper)

Analysis of laser surgery in non-melanoma skin cancer for optimal tissue removal

Science.gov (United States)

Fanjul-Vélez, Félix; Salas-García, Irene; Arce-Diego, José Luis

2015-02-01

Laser surgery is a commonly used technique for tissue ablation or the resection of malignant tumors. It presents advantages over conventional non-optical ablation techniques, like a scalpel or electrosurgery, such as the increased precision of the resected volume, minimization of scars and shorter recovery periods. Laser surgery is employed in medical branches such as ophthalmology or dermatology. The application of laser surgery requires the optimal adjustment of laser beam parameters, taking into account the particular patient and lesion. In this work we present a predictive tool for tissue resection in biological tissue after laser surgery, which allows an a priori knowledge of the tissue ablation volume, area and depth. The model employs a Monte Carlo 3D approach for optical propagation and a rate equation for plasma-induced ablation. The tool takes into account characteristics of the specific lesion to be ablated, mainly the geometric, optical and ablation properties. It also considers the parameters of the laser beam, such as the radius, spatial profile, pulse width, total delivered energy or wavelength. The predictive tool is applied to dermatology tumor resection, particularly to different types of non-melanoma skin cancer tumors: basocellular carcinoma, squamous cell carcinoma and infiltrative carcinoma. The ablation volume, area and depth are calculated for healthy skin and for each type of tumor as a function of the laser beam parameters. The tool could be used for laser surgery planning before the clinical application. The laser parameters could be adjusted for optimal resection volume, by personalizing the process to the particular patient and lesion.

Menstrual variation of breast volume and T{sub 2} relaxation times in cyclical mastalgia

Energy Technology Data Exchange (ETDEWEB)

Hussain, Zainab [Department of Medical Imaging, University of Liverpool, Johnstone Building, Brownlow Hill, P.O. Box 147, Liverpool, Merseyside L69 3GB (United Kingdom); Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, Johnstone Building, Brownlow Hill, P.O. Box 147, Liverpool, Merseyside L69 3GB (United Kingdom)], E-mail: zay@liverpool.ac.uk; Brooks, Jonathan [Magnetic Resonance and Image Analysis Research Centre, University of Liverpool, Johnstone Building, Brownlow Hill, P.O. Box 147, Liverpool, Merseyside L69 3GB (United Kingdom); Department of Human Anatomy and Genetics, University of Oxford, Oxford (United Kingdom); Percy, Dave [Centre for Operational Research and Applied Statistics, University of Salford, Salford, Greater Manchester M5 4WT (United Kingdom)

2008-02-15

Purpose: Hormonal activity causes breast volume to change during the menstrual cycle. One possible cause of this volume change is thought to be due to water retention or oedema within the tissues. We used magnetic resonance imaging (MRI) to study the variation in breast volume and {sup 1}H Magnetic Resonance Spectroscopy (MRS) to measure T{sub 2} relaxation times which are known to increase with increasing tissue water content. We hypothesised that an increase in breast volume will elevate T{sub 2} relaxation due to the presence of an increased water content within the breast. T{sub 2} Relaxation time and volume were studied in fifteen control subjects and in a cohort of eight patients with cyclical mastalgia in order to determine whether changes in breast volume and T{sub 2} relaxation times differed in controls and patients during menses, ovulation and premenses. Method: Breast volume was determined by the Cavalieri method in combination with point counting techniques on MR images and T{sub 2} relaxation times of the water and fat in a voxel of breast tissue were obtained using {sup 1}H Magnetic Resonance Spectroscopy (MRS). Results: Statistical analysis (ANOVA) demonstrated highly significant differences in breast volume between the three stages of the cycle (p < 0.0005) with breast volume being greatest premenstrually. Patients did not exhibit an increase in volume premenstrually, significantly above controls. T{sub 2} of fat or water did not depend on stage of cycle. T-tests demonstrated no significant differences in T{sub 2} of water or fat between patient and control groups. The average T{sub 2} relaxation time of water was lowest in the patient and control groups during ovulation and highest in the patient group during premenses. Conclusion: We have performed the first combined volumetric and spectroscopic study of women with cyclical mastalgia and demonstrated that the global changes in volumes and T{sub 2} were not significantly different from normal

Assessment of edema volume in skin upon injury in a mouse ear model with optical coherence tomography

Science.gov (United States)

Qin, Wan

2017-01-01

Accurate measurement of edema volume is essential for the investigation of tissue response and recovery following a traumatic injury. The measurements must be noninvasive and repetitive over time so as to monitor tissue response throughout the healing process. Such techniques are particularly necessary for the evaluation of therapeutics that are currently in development to suppress or prevent edema formation. In this study, we propose to use optical coherence tomography (OCT) technique to image and quantify edema in a mouse ear model where the injury is induced by a superficial-thickness burn. Extraction of edema volume is achieved by an attenuation compensation algorithm performed on the three-dimensional OCT images, followed by two segmentation procedures. In addition to edema volume, the segmentation method also enables accurate thickness mapping of edematous tissue, which is an important characteristic of the external symptoms of edema. To the best of our knowledge, this is the first method for noninvasively measuring absolute edema volume. PMID:27282161

A local contrast based approach to threshold segmentation for PET target volume delineation

International Nuclear Information System (INIS)

Drever, Laura; Robinson, Don M.; McEwan, Alexander; Roa, Wilson

2006-01-01

Current radiation therapy techniques, such as intensity modulated radiation therapy and three-dimensional conformal radiotherapy rely on the precise delivery of high doses of radiation to well-defined volumes. CT, the imaging modality that is most commonly used to determine treatment volumes cannot, however, easily distinguish between cancerous and normal tissue. The ability of positron emission tomography (PET) to more readily differentiate between malignant and healthy tissues has generated great interest in using PET images to delineate target volumes for radiation treatment planning. At present the accurate geometric delineation of tumor volumes is a subject open to considerable interpretation. The possibility of using a local contrast based approach to threshold segmentation to accurately delineate PET target cross sections is investigated using well-defined cylindrical and spherical volumes. Contrast levels which yield correct volumetric quantification are found to be a function of the activity concentration ratio between target and background, target size, and slice location. Possibilities for clinical implementation are explored along with the limits posed by this form of segmentation

Gestalt Breastfeeding: Helping Mothers and Infants Optimize Positional Stability and Intraoral Breast Tissue Volume for Effective, Pain-Free Milk Transfer.

Science.gov (United States)

Douglas, Pamela; Keogh, Renee

2017-08-01

In the past decade, biological nurturing and activation of maternal and infant instincts after birth have constituted a major advance in clinical breastfeeding support. Yet, physiologic breastfeeding initiation is not enough to ensure ongoing pain-free and effective breastfeeding for many pairs. Current interventions, including "hands-off" mammalian approaches, do not improve breastfeeding outcomes, including in randomized controlled trials. Back-arching, difficulty latching or staying on the breast, and fussing at the breast are common signs of infant positional instability during breastfeeding. These cues are, however, often misdiagnosed as signs of medical conditions or oral connective tissue abnormalities, and underlying positional instability is not addressed. New clinical approaches are urgently required. This article offers a clinical approach to fit and hold (or latch and positioning)- gestalt breastfeeding, which aims to optimize positional stability and intraoral breast tissue volumes for pain-free effective breastfeeding. The word gestalt (pronounced "ger-shtolt") means a whole that is more than the sum of its parts. Gestalt breastfeeding builds on the theoretical foundations of complexity science, physiologic breastfeeding initiation, and new understandings of the biomechanics of infant suck elucidated in ultrasound studies. It also integrates simple psychological strategies from applied functional contextualism, popularly known as Acceptance and Commitment Therapy, empowering women to attend mindfully to breast sensations and their infant's cues. Gestalt breastfeeding can be reproduced for research purposes, including in comparison studies with oral surgery, and has the potential to improve breastfeeding outcomes.

Pancreatic polypeptide: Identification of target tissues and investigation of possible physiologic significance

International Nuclear Information System (INIS)

Shetzline, M.A.

1988-01-01

Pancreatic Polypeptide (PP) is a 36 amino acid peptide with hormonal properties but whose physiologic function remains unknown. In order to determine the function of this peptide we investigated potential target tissues using an in vivo radioreceptor assay. In vitro high concentrations of unlabeled hormone competitively inhibit low concentrations of labeled hormone from binding to receptors. Our in vivo studies indicate that, in the presence of concentrated unlabeled peptide, labeled PP distributes between the plasma and interstitial fluid. When saline rather than excess unlabeled PP is injected, the labeled peptide appears to distribute in a volume exceeding the combined plasma and interstitial fluid volume of tissue. The distribution volume which exceeds the anatomic extracellular volume and which is not present with excess unlabeled peptide, is the receptor compartment. With this assay we demonstrated in the rat specific and displaceable PP binding to the ductus choledochus, duodenum, ileum, and adrenal gland. In vitro rat adrenal cell membranes showed specific I-125 labeled PP binding. Specific binding also occurred in bovine cortical and medullary membranes

Use of Artelon® Cosmetic in soft tissue augmentation in dentistry

Directory of Open Access Journals (Sweden)

Ko YK

2011-06-01

Full Text Available Youngkyung Ko, NamRyang Kim, Seojin Park, Jun-Beom ParkDepartment of Periodontics, Seoul St Mary's Hospital, The Catholic University of Korea, Seoul, KoreaBackground: Soft tissue augmentation is a widely used procedure in partially and fully edentulous patients to increase soft tissue volume. Polyurethanes have been used for scaffolds in a variety of implantable devices. Artelon® is a degradable polyurethane that has been manufactured as fibers, films, and porous scaffolds to be used for various purposes. In this review, the characteristics of Artelon are described, and its clinical applications in orthopedics, dermatology, cardiovascular medicine, and dentistry are also discussed.Methods: A Medline (PubMed search was conducted, and articles published in English were included. Keywords, including “Artelon”, “polyurethanes”, “soft tissue augmentation”, “biocompatibility”, “resorption”, “mechanical stability”, and “complications” were used in different combinations. Titles and abstracts were screened, and full text article analyses were performed.Results: Most of the studies reported orthopedic, dermal, and myocardial applications. There were only a few reports related to dental and implant applications. Artelon has been successfully used for reinforcement of soft tissues, including the rotator cuff, Achilles, patellar, biceps, and quadriceps tendons in orthopedic surgery, and is used clinically for the treatment of osteoarthritis in the hand, wrist, and foot. One type of Artelon material, Artelon Cosmetic, has been used in the dental field to increase soft tissue volume, and stable results are achieved for up to 6 months. This material is reported to be easily handled when cut to the desired shape, with little additional time needed for manipulation during surgery, eliminates the need for connective tissue autografts, and thereby decreases patient morbidity and postoperative discomfort, with increased likelihood of a

Initial study of optimal single-voxel 1H-MR spectroscopy parameters on femoral bone marrow

International Nuclear Information System (INIS)

Gao Zhenhua; Meng Quanfei; Zhou Chunxiang; Lin Erjian; Deng Demao

2007-01-01

Objective: To choose proper proton magnetic resonance spectroscopy ( 1 H-MRS) parameters to fit for practical femoral marrow cavity and to produce short-timed, well-repeated and excellent 1 H-MRS images. Methods: The tentative study of 1 H-MRS on the normal femoral bone marrow in 26 volunteers was performed with a 1.5 T MR after the informed consent. The single-voxel spectroscopy and stimulated echo acquisition mode were used for 1 H-MRS collection. 1 H-MRS parameters for 12 volunteers were 128 acquisitions, 1 cm x 1 cm x 1 cm volume of interest (VOI) size and repeatedly 2-3 times within the same location. 1 H-MRS parameters for another 14 volunteers were different numbers of acquisition (128 and 256 times, respectively) and different VOl sizes (2 cm x2 cm x2 cm and 1 cm x 1 cm x 1 cm, respectively). Results: For 1 H-MRS with 1 cm x 1 cm x 1 cm size of VOI and 128 times of acquisition with the full width half max of water ≤8-12 Hz, the base-line was steady and the signal-noise ratio was high up to 11.31. 1 H-MRS was different in the different femoral locations showing the maximum peak sites at near 0.90 ppm( x 10 -6 ) or 1.65 ppm, but 1 H-MRS within the same location was always same or similar with different VOI sizes (1 cm x 1 cm x 1 cm or 2 cm x 2 cm x 2 cm) or different numbers of acquisition(128 or 256 times). 1 H-MRS acquisition time was not related with the size of VOI but with the numbers of acquisition. 128 and 256 times of acquisition cost 199 s and 391 s, respectively. Conclusion: With the technique of small size of VOI(1 cm x 1 cm x 1 cm) and decreased numbers of acquisition (128 times), it is propable to get well-repeated and excellent 1 H-MRS within less time. It is also more practical for clinics to achieve 1 H-MRS of the femoral marrow with the proper technique. (authors)

Effect of Strain, Region, and Tissue Composition on Glucose Partitioning in Meniscus Fibrocartilage.

Science.gov (United States)

Kleinhans, Kelsey L; Jackson, Alicia R

2017-03-01

A nearly avascular tissue, the knee meniscus relies on diffusive transport for nutritional supply to cells. Nutrient transport depends on solute partitioning in the tissue, which governs the amount of nutrients that can enter a tissue. The purpose of the present study was to investigate the effects of mechanical strain, tissue region, and tissue composition on the partition coefficient of glucose in meniscus fibrocartilage. A simple partitioning experiment was employed to measure glucose partitioning in porcine meniscus tissues from two regions (horn and central), from both meniscal components (medial and lateral), and at three levels of compression (0%, 10%, and 20%). Partition coefficient values were correlated to strain level, water volume fraction, and glycosaminoglycan (GAG) content of tissue specimens. Partition coefficient values ranged from 0.47 to 0.91 (n = 48). Results show that glucose partition coefficient is significantly (p < 0.001) affected by compression, decreasing with increasing strain. Furthermore, we did not find a statistically significant effect of tissue when comparing medial versus lateral (p = 0.181) or when comparing central and horn regions (p = 0.837). There were significant positive correlations between tissue water volume fraction and glucose partitioning for all groups. However, the correlation between GAG content and partitioning was only significant in the lateral horn group. Determining how glucose partitioning is affected by tissue composition and loading is necessary for understanding nutrient availability and related tissue health and/or degeneration. Therefore, this study is important for better understanding the transport and nutrition-related mechanisms of meniscal degeneration.

Validity of soft-tissue thickness of calf measured using MRI for assessing unilateral lower extremity lymphoedema secondary to cervical and endometrial cancer treatments

International Nuclear Information System (INIS)

Lu, Qing; Li, Yulai; Chen, Tian-Wu; Yao, Yuan; Zhao, Zizhou; Li, Yang; Xu, Jianrong; Jiang, Zhaohua; Hu, Jiani

2014-01-01

Aim: To determine whether soft-tissue thickness of the calf measured using MRI could be valid for assessing unilateral lower extremity lymphoedema (LEL) secondary to cervical and endometrial cancer treatments. Materials and methods: Seventy women with unilateral LEL and 25 without LEL after cervical or endometrial cancer treatments underwent MRI examinations of their calves. Total thickness of soft-tissue (TT), muscle thickness (MT), and subcutaneous tissue thickness (STT) of the calf, and the difference between the affected and contralateral unaffected calf regarding TT (DTT), MT (DMT), and STT (DSTT) were obtained using fat-suppressed T2-weighted imaging in the middle of the calves. The volume of the calf and difference in volume (DV) between calves were obtained by the method of water displacement. Statistical analysis was performed to determine the validity of MRI measurements by volume measurements in staging LEL. Results: There was a close correlation between volume and TT for the affected (r = 0.927) or unaffected calves (r = 0.896). STT of the affected calf, and DTT or DSTT of the calves were closely correlated with volume of the affected calf or DV of the calves (all p < 0.05). Multivariate analysis showed significant differences in TT, STT, volume of the affected calf, DTT, DSTT, and DV between stages except in volume of the affected calf or in DV between stage 0 and 1. For staging LEL, DSTT showed the best discrimination ability among all the parameters. Conclusions: Soft-tissue thickness of the calf measured at MRI could be valid for quantitatively staging unilateral LEL, and DSTT of the calves could be the best classifying factor. - Highlights: • The soft tissue thickness of calves on MRI could quantitatively assess secondary LEL. • Calf soft tissue thickness indicated concurrent or construct validity of calf volume. • The difference of subcutaneous tissue thickness of calves could be used to stage LEL

Evaluation of the relationship between extremity soft tissue sarcomas and adjacent major vessels using contrast-enhanced multidetector CT and three-dimensional volume-rendered CT angiography - A preliminary study

International Nuclear Information System (INIS)

Li, YangKang; Lin, JianBang; Cai, AiQun; Zhou, XiuGuo; Zheng, Yu; Wei, XiaoLong; Cheng, Ying; Liu, GuoRui

2013-01-01

Background: Accurate description of the relationship between extremity soft tissue sarcoma and the adjacent major vessels is crucial for successful surgery. In addition to magnetic resonance imaging (MRI) or in patients who cannot undergo MRI, two-dimensional (2D) postcontrast computed tomography (CT) images and three-dimensional (3D) volume-rendered CT angiography may be valuable alternative imaging techniques for preoperative evaluation of extremity sarcomas. Purpose: To preoperatively assess extremity sarcomas using multidetector CT (MDCT), with emphasis on postcontrast MDCT images and 3D volume-rendered MDCT angiography in evaluating the relationship between tumors and adjacent major vessels. Material and Methods: MDCT examinations were performed on 13 patients with non-metastatic extremity sarcomas. Conventional CT images and 3D volume-rendered CT angiography were evaluated, with focus on the relationship between tumors and adjacent major vessels. Kappa consistency statistics were performed with surgery serving as the reference standard. Results: The relationship between sarcomas and adjacent vessels was described as one of three patterns: proximity, adhesion, and encasement. Proximity was seen in five cases on postcontrast CT images or in eight cases on volume-rendered images. Adhesion was seen in three cases on both postcontrast CT images and volume-rendered images. Encasement was seen in five cases on postcontrast CT images or in two cases on volume-rendered images. Compared to surgical results, postcontrast CT images had 100% sensitivity, 83.3% specificity, 87.5% positive predictive value, 100% negative predictive value, and 92.3% accuracy in the detection of vascular invasion (κ = 0.843, P = 0.002). 3D volume-rendered CT angiography had 71.4% sensitivity, 100% specificity, 100% positive predictive value, 75% negative predictive value, and 84.6% accuracy in the detection of vascular invasion (κ = 0.698, P = 0.008). On volume-rendered images, all cases

Language and Brain Volumes in Children with Epilepsy

Science.gov (United States)

Caplan, Rochelle; Levitt, Jennifer; Siddarth, Prabha; Wu, Keng Nei; Gurbani, Suresh; Shields, W. Donald; Sankar, Raman

2010-01-01

This study compared the relationship of language skill with fronto-temporal volumes in 69 medically treated epilepsy subjects and 34 healthy children, aged 6.1-16.6 years. It also determined if the patients with linguistic deficits had abnormal volumes and atypical associations between volumes and language skills in these brain regions. The children underwent language testing and magnetic resonance imaging scans at 1.5 Tesla. Brain tissue was segmented and fronto-temporal volumes were computed. Higher mean language scores were significantly associated with larger inferior frontal gyrus, temporal lobe, and posterior superior temporal gyrus gray matter volumes in the epilepsy group and in the children with epilepsy with average language scores. Increased total brain and dorsolateral prefrontal gray and white matter volumes, however, were associated with higher language scores in the healthy controls. Within the epilepsy group, linguistic deficits were related to smaller anterior superior temporal gyrus gray matter volumes and a negative association between language scores and dorsolateral prefrontal gray matter volumes. These findings demonstrate abnormal development of language related brain regions, and imply differential reorganization of brain regions subserving language in children with epilepsy with normal linguistic skills and in those with impaired language. PMID:20149755

Novel genetic loci underlying human intracranial volume identified through genome-wide association

OpenAIRE

Adams, Hieab HH; Hibar, Derrek P; Chouraki, Vincent; Stein, Jason L; Nyquist, Paul A; Renter��a, Miguel E; Trompet, Stella; Arias-Vasquez, Alejandro; Seshadri, Sudha; Desrivi��res, Sylvane; Beecham, Ashley H; Jahanshad, Neda; Wittfeld, Katharina; Van der Lee, Sven J; Abramovic, Lucija

2016-01-01

Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438 adults, we discovered five previously unknown loci for intracranial volume and confirmed two known signals. Four of the loci were also associated with adult human stature, but these remained associated with intracranial volume after adjus...

Effects of a Multidisciplinary Approach to Improve Volume of Diagnostic Material in CT-Guided Lung Biopsies.

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Ferguson, Philip E; Sales, Catherine M; Hodges, Dalton C; Sales, Elizabeth W

2015-01-01

Recent publications have emphasized the importance of a multidisciplinary strategy for maximum conservation and utilization of lung biopsy material for advanced testing, which may determine therapy. This paper quantifies the effect of a multidisciplinary strategy implemented to optimize and increase tissue volume in CT-guided transthoracic needle core lung biopsies. The strategy was three-pronged: (1) once there was confidence diagnostic tissue had been obtained and if safe for the patient, additional biopsy passes were performed to further increase volume of biopsy material, (2) biopsy material was placed in multiple cassettes for processing, and (3) all tissue ribbons were conserved when cutting blocks in the histology laboratory. This study quantifies the effects of strategies #1 and #2. This retrospective analysis comparing CT-guided lung biopsies from 2007 and 2012 (before and after multidisciplinary approach implementation) was performed at a single institution. Patient medical records were reviewed and main variables analyzed include biopsy sample size, radiologist, number of blocks submitted, diagnosis, and complications. The biopsy sample size measured was considered to be directly proportional to tissue volume in the block. Biopsy sample size increased 2.5 fold with the average total biopsy sample size increasing from 1.0 cm (0.9-1.1 cm) in 2007 to 2.5 cm (2.3-2.8 cm) in 2012 (Pstrategy to CT-guided lung biopsies was effective in significantly increasing tissue volume and number of blocks available for advanced diagnostic testing.

MR imaging of experimental subdural bleeding. Correlates of brain deformation and tissue water content, and changes in vital physiological parameters

International Nuclear Information System (INIS)

Orlin, J.R.; Thuomas, K.Aa.; Ponten, U.; Bergstroem, K.; Zwetnow, N.N.

1997-01-01

Purpose: To evaluate morphological and physiological changes during acute lethal subdural bleeding in 2 models of anaesthetized dogs. Material and Methods: In model I, blood from the aorta was led into a collapsed subdural rubber balloon while in model II, the blood was directed into the subdural compartment over the left cerebral frontoparietal lobe. Eight vital physiological parameters were continuously registered. MR imaging visualized the compression and displacement of cerebral tissue, and assessed the dynamic changes in cerebral tissue water. Results: In model I, tissue herniation and compression of cerebral ventricles led to death at a haematoma volume corresponding to 8% of the intracranial volume. In model II, the extravasated blood progressed infratentorially and into the spinal sac with a volume that was 3 times larger than that of the lethal haematoma. Tissue water increased almost linearly during bleeding in both models. (orig.)

Evaluation of the response to preoperative chemotherapy with PET image in osteosarcoma

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Jeon, Dae Geun; Lee, Jong Seok; Kim, Sug Jun; Lee, Soo Yong

1999-12-01

F18 FDG PET scan has an advantage in evaluating the biologic status of the tumors. The purpose of this study is evaluate the role of PET scan in pre- and post chemotherapeutic osteosarcomas and correlate the findings with pathologic examination. Nine cases of osteosarcoma had biopsy and preoperative chemotherapy at our department. There were 4 distal femur, 4 proximal tibia and 1 distal ulna. All case had initial MRI and PET scan and these were repeated after 2 cycles of chemotherapy. Under PET image parameters such as VOI (volume of interest), total activity, degree of necrosis and T/N (tumor/normal tissue) ratio were analyzed. There was a significant correlation between the calculated necrosis in PET and observed one on pathologic specimen (r2=0.78, p<0.05). Cross correlation among identified variables revealed meaningful result between T/N ration and tumor necrosis (r2=0.45, p<0.05). As the T/N ratio decrease, so much more the tumor necrosis was. F18 FDG PET scan could get objective data such as volume, degree of necrosis and total activity and was also useful in estimating the contribution of chemotherapy in tumor necrosis over the innate necrosis before treatment.

Evaluation of the response to preoperative chemotherapy with PET image in osteosarcoma

International Nuclear Information System (INIS)

Jeon, Dae Geun; Lee, Jong Seok; Kim, Sug Jun; Lee, Soo Yong

1999-12-01

F18 FDG PET scan has an advantage in evaluating the biologic status of the tumors. The purpose of this study is evaluate the role of PET scan in pre- and post chemotherapeutic osteosarcomas and correlate the findings with pathologic examination. Nine cases of osteosarcoma had biopsy and preoperative chemotherapy at our department. There were 4 distal femur, 4 proximal tibia and 1 distal ulna. All case had initial MRI and PET scan and these were repeated after 2 cycles of chemotherapy. Under PET image parameters such as VOI (volume of interest), total activity, degree of necrosis and T/N (tumor/normal tissue) ratio were analyzed. There was a significant correlation between the calculated necrosis in PET and observed one on pathologic specimen (r2=0.78, p<0.05). Cross correlation among identified variables revealed meaningful result between T/N ration and tumor necrosis (r2=0.45, p<0.05). As the T/N ratio decrease, so much more the tumor necrosis was. F18 FDG PET scan could get objective data such as volume, degree of necrosis and total activity and was also useful in estimating the contribution of chemotherapy in tumor necrosis over the innate necrosis before treatment

Reconstruction for Skull Base Defect Using Fat-Containing Perifascial Areolar Tissue.

Science.gov (United States)

Choi, Woo Young; Sung, Ki Wook; Kim, Young Seok; Hong, Jong Won; Roh, Tai Suk; Lew, Dae Hyun; Chang, Jong Hee; Lee, Kyu Sung

2017-06-01

Skull base reconstruction is a challenging task. The method depends on the anatomical complexity and size of the defect. We obtained tissue by harvesting fat-containing perifascial areolar tissue (PAT) for reconstruction of limited skull base defects and volume augmentation. We demonstrated the effective option for reconstruction of limited skull base defects and volume augmentation. From October 2013 to November 2015, 5 patients underwent operations using fat-containing PAT to fill the defect in skull base and/or perform volume replacement in the forehead. Perifascial areolar tissue with 5- to 10-mm fat thickness was harvested from the inguinal region. The fat-containing PAT was grafted to the defect contacting the vascularized wound bed. Patients were followed up in terms of their clinical symptoms and postoperative magnetic resonance imaging findings. Four patients were treated using fat-containing PAT after tumor resection. One patient was treated for a posttraumatic forehead depression deformity. The fat-containing PAT included 5- to 9-mm fat thickness in all cases. The mean size of grafted PAT was 65.6 cm (28-140 cm). The mean follow-up period was 18.6 months (12-31 months). There was no notable complication. There was no donor site morbidity. We can harvest PAT with fat easily and obtain the sufficient volume to treat the defect. It also could be used with other reconstructive method, such as a free flap or a regional flap to fill the left dead space. Therefore, fat-containing PAT could be additional options to reconstruction of skull base defect.

Incidence of late rectal bleeding in high-dose conformal radiotherapy of prostate cancer using equivalent uniform dose-based and dose-volume-based normal tissue complication probability models

International Nuclear Information System (INIS)

Soehn, Matthias; Yan Di; Liang Jian; Meldolesi, Elisa; Vargas, Carlos; Alber, Markus

2007-01-01

Purpose: Accurate modeling of rectal complications based on dose-volume histogram (DVH) data are necessary to allow safe dose escalation in radiotherapy of prostate cancer. We applied different equivalent uniform dose (EUD)-based and dose-volume-based normal tissue complication probability (NTCP) models to rectal wall DVHs and follow-up data for 319 prostate cancer patients to identify the dosimetric factors most predictive for Grade ≥ 2 rectal bleeding. Methods and Materials: Data for 319 patients treated at the William Beaumont Hospital with three-dimensional conformal radiotherapy (3D-CRT) under an adaptive radiotherapy protocol were used for this study. The following models were considered: (1) Lyman model and (2) logit-formula with DVH reduced to generalized EUD (3) serial reconstruction unit (RU) model (4) Poisson-EUD model, and (5) mean dose- and (6) cutoff dose-logistic regression model. The parameters and their confidence intervals were determined using maximum likelihood estimation. Results: Of the patients, 51 (16.0%) showed Grade 2 or higher bleeding. As assessed qualitatively and quantitatively, the Lyman- and Logit-EUD, serial RU, and Poisson-EUD model fitted the data very well. Rectal wall mean dose did not correlate to Grade 2 or higher bleeding. For the cutoff dose model, the volume receiving > 73.7 Gy showed most significant correlation to bleeding. However, this model fitted the data more poorly than the EUD-based models. Conclusions: Our study clearly confirms a volume effect for late rectal bleeding. This can be described very well by the EUD-like models, of which the serial RU- and Poisson-EUD model can describe the data with only two parameters. Dose-volume-based cutoff-dose models performed worse

Tumor and normal tissue responses to fractioned non-uniform dose delivery

Energy Technology Data Exchange (ETDEWEB)

Kaellman, P; Aegren, A; Brahme, A [Karolinska Inst., Stockholm (Sweden). Dept. of Radiation Physics

1996-08-01

The volume dependence of the radiation response of a tumor is straight forward to quantify because it depends primarily on the eradication of all its clonogenic cells. A tumor therefore has a parallel organization as any surviving clonogen in principle can repopulate the tumor. The difficulty with the response of the tumor is instead to know the density and sensitivity distribution of the most resistant clonogenic cells. The increase in the 50% tumor control dose and the decrease in the maximum normalized slope of the dose response relation, {gamma}, in presence of small compartments of resistant tumor cells have therefore been quantified to describe their influence on the dose response relation. Injury to normal tissue is a much more complex and gradual process. It depends on earlier effects induced long before depletion of the differentiated and clonogenic cells that in addition may have a complex structural and functional organization. The volume dependence of the dose response relation of normal tissues is therefore described here by the relative seriality, s, of the infrastructure of the organ. The model can also be generalized to describe the response of heterogeneous tissues to non uniform dose distributions. The new model is compared with clinical and experimental data on normal tissue response, and shows good agreement both with regard to the shape of dose response relation and the volume dependence of the isoeffect dose. The response of tumors and normal tissues are quantified for arbitrary dose fractionations using the linear quadratic cell survival parameters {alpha} and {beta}. The parameters of the dose response relation are derived both for a constant dose per fraction and a constant number of dose fractions, thus in the latter case accounting also for non uniform dose delivery. (author). 26 refs, 4 figs.

Changes in dose with segmentation of breast tissues in Monte Carlo calculations for low-energy brachytherapy

International Nuclear Information System (INIS)

Sutherland, J. G. H.; Thomson, R. M.; Rogers, D. W. O.

2011-01-01

Purpose: To investigate the use of various breast tissue segmentation models in Monte Carlo dose calculations for low-energy brachytherapy. Methods: The EGSnrc user-code BrachyDose is used to perform Monte Carlo simulations of a breast brachytherapy treatment using TheraSeed Pd-103 seeds with various breast tissue segmentation models. Models used include a phantom where voxels are randomly assigned to be gland or adipose (randomly segmented), a phantom where a single tissue of averaged gland and adipose is present (averaged tissue), and a realistically segmented phantom created from previously published numerical phantoms. Radiation transport in averaged tissue while scoring in gland along with other combinations is investigated. The inclusion of calcifications in the breast is also studied in averaged tissue and randomly segmented phantoms. Results: In randomly segmented and averaged tissue phantoms, the photon energy fluence is approximately the same; however, differences occur in the dose volume histograms (DVHs) as a result of scoring in the different tissues (gland and adipose versus averaged tissue), whose mass energy absorption coefficients differ by 30%. A realistically segmented phantom is shown to significantly change the photon energy fluence compared to that in averaged tissue or randomly segmented phantoms. Despite this, resulting DVHs for the entire treatment volume agree reasonably because fluence differences are compensated by dose scoring differences. DVHs for the dose to only the gland voxels in a realistically segmented phantom do not agree with those for dose to gland in an averaged tissue phantom. Calcifications affect photon energy fluence to such a degree that the differences in fluence are not compensated for (as they are in the no calcification case) by dose scoring in averaged tissue phantoms. Conclusions: For low-energy brachytherapy, if photon transport and dose scoring both occur in an averaged tissue, the resulting DVH for the entire

Changes in dose with segmentation of breast tissues in Monte Carlo calculations for low-energy brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Sutherland, J. G. H.; Thomson, R. M.; Rogers, D. W. O. [Carleton Laboratory for Radiotherapy Physics, Department of Physics, Carleton University, Ottawa K1S 5B6 (Canada)

2011-08-15

Purpose: To investigate the use of various breast tissue segmentation models in Monte Carlo dose calculations for low-energy brachytherapy. Methods: The EGSnrc user-code BrachyDose is used to perform Monte Carlo simulations of a breast brachytherapy treatment using TheraSeed Pd-103 seeds with various breast tissue segmentation models. Models used include a phantom where voxels are randomly assigned to be gland or adipose (randomly segmented), a phantom where a single tissue of averaged gland and adipose is present (averaged tissue), and a realistically segmented phantom created from previously published numerical phantoms. Radiation transport in averaged tissue while scoring in gland along with other combinations is investigated. The inclusion of calcifications in the breast is also studied in averaged tissue and randomly segmented phantoms. Results: In randomly segmented and averaged tissue phantoms, the photon energy fluence is approximately the same; however, differences occur in the dose volume histograms (DVHs) as a result of scoring in the different tissues (gland and adipose versus averaged tissue), whose mass energy absorption coefficients differ by 30%. A realistically segmented phantom is shown to significantly change the photon energy fluence compared to that in averaged tissue or randomly segmented phantoms. Despite this, resulting DVHs for the entire treatment volume agree reasonably because fluence differences are compensated by dose scoring differences. DVHs for the dose to only the gland voxels in a realistically segmented phantom do not agree with those for dose to gland in an averaged tissue phantom. Calcifications affect photon energy fluence to such a degree that the differences in fluence are not compensated for (as they are in the no calcification case) by dose scoring in averaged tissue phantoms. Conclusions: For low-energy brachytherapy, if photon transport and dose scoring both occur in an averaged tissue, the resulting DVH for the entire

Bones - joints - soft tissues II. 7. rev. ed.

International Nuclear Information System (INIS)

Dihlmann, W.; Frommhold, W.

1991-01-01

With the publication of the 2nd part to Volume VI, 'Bones - joints - soft tissues', the 7th edition of 'Diagnostic radiology in the hospital and medical practice' is complete. The advances made particularly during the past decade in the field of diagnostic radiology have made it neccesary for all the individual sections to be completely revised. Recently developed methods of imaging like sonography, computed tomography and magnetic resonance tomography are increasingly used as a replacement for or, at least, an adjunct to conventional X-ray procedures. Owing to the development and continuous refinement of related methods of intervention the gap between mere diagnostic applications and therapeutic uses of radiology could eventually be closed. The issues mainly discussed in this volume are bone fractures and healing, bone transplantation, osteopathy and osteoarthropathy, fibrous dyplasia or Albright's disease, Pagetoid osteitis, genetically transmitted constitutional disorders of the skeleton and soft tissue changes. While in the key sections on bone fractures and healing, osteopathy and osteoarthropathy as well as constitutional genetic disorders X-ray techniques are still described as the prevailing method of diagnosis, diseases of soft tissues now are much more commonly diagnosed using magnetic resonance imaging. (orig./MG) With 2248 figs., 59 tabs [de

Effect of the Epicardial Adipose Tissue Volume on the Prevalence of Paroxysmal and Persistent Atrial Fibrillation.

Science.gov (United States)

Oba, Kageyuki; Maeda, Minetaka; Maimaituxun, Gulinu; Yamaguchi, Satoshi; Arasaki, Osamu; Fukuda, Daiju; Yagi, Shusuke; Hirata, Yukina; Nishio, Susumu; Iwase, Takashi; Takao, Shoichiro; Kusunose, Kenya; Yamada, Hirotsugu; Soeki, Takeshi; Wakatsuki, Tetsuzo; Harada, Masafumi; Masuzaki, Hiroaki; Sata, Masataka; Shimabukuro, Michio

2018-05-25

Although increasing evidence suggests that epicardial adipose tissue volume (EATV) is associated with atrial fibrillation (AF), it is controversial whether there is a dose-response relationship of increasing EATV along the continuum of AF. We evaluated the effect of the EATV on the prevalence of paroxysmal AF (PAF) and persistent AF (PeAF) and the relationships with cardiac structure and functional remodeling.Methods and Results:Subjects who underwent multidetector computed tomography (MDCT) coronary angiography because of symptoms suggestive of coronary artery disease were divided into sinus rhythm (SR) (n=112), PAF (n=133), and PeAF (n=71) groups. The EATV index (EATV/body surface area, mL/m 2 ) was strongly associated with the prevalence of PAF and PeAF on the model adjusted for known AF risk factors. The effect of the EATV index on the prevalence of PeAF, but not on that of PAF, was modified by the left atrial (LA) dimension, suggesting that extension of the LA dimension is related to EATV expansion in PeAF. The cutoff value of the EATV index for the prevalence was higher in PeAF than in PAF (64 vs. 55 mL/m 2 , PEATV index is associated with the prevalence of PAF and PeAF, and its cutoff values are predictive for PAF and PeAF development independently of other AF risk factors.

Analyzing the effects of mechanical and osmotic loading on glycosaminoglycan synthesis rate in cartilaginous tissues.

Science.gov (United States)

Gao, Xin; Zhu, Qiaoqiao; Gu, Weiyong

2015-02-26

The glycosaminoglycan (GAG) plays an important role in cartilaginous tissues to support and transmit mechanical loads. Many extracellular biophysical stimuli could affect GAG synthesis by cells. It has been hypothesized that the change of cell volume is a primary mechanism for cells to perceive the stimuli. Experimental studies have shown that the maximum synthesis rate of GAG is achieved at an optimal cell volume, larger or smaller than this level the GAG synthesis rate decreases. Based on the hypothesis and experimental findings in the literature, we proposed a mathematical model to quantitatively describe the cell volume dependent GAG synthesis rate in the cartilaginous tissues. Using this model, we investigated the effects of osmotic loading and mechanical loading on GAG synthesis rate. It is found our proposed mathematical model is able to well describe the change of GAG synthesis rate in isolated cells or in cartilage with variations of the osmotic loading or mechanical loading. This model is important for evaluating the GAG synthesis activity within cartilaginous tissues as well as understanding the role of mechanical loading in tissue growth or degeneration. It is also important for designing a bioreactor system with proper extracellular environment or mechanical loading for growing tissue at the maximum synthesis rate of the extracellular matrix. Copyright © 2015 Elsevier Ltd. All rights reserved.

X-ray volume imaging in bladder radiotherapy verification

International Nuclear Information System (INIS)

Henry, Ann M.; Stratford, Julia; McCarthy, Claire; Davies, Julie; Sykes, Jonathan R.; Amer, Ali; Marchant, Tom; Cowan, Richard; Wylie, James; Logue, John; Livsey, Jacqueline; Khoo, Vincent S.; Moore, Chris; Price, Pat

2006-01-01

Purpose: To assess the clinical utility of X-ray volume imaging (XVI) for verification of bladder radiotherapy and to quantify geometric error in bladder radiotherapy delivery. Methods and Materials: Twenty subjects undergoing conformal bladder radiotherapy were recruited. X-ray volume images and electronic portal images (EPIs) were acquired for the first 5 fractions and then once weekly. X-ray volume images were co-registered with the planning computed tomography scan and clinical target volume coverage assessed in three dimensions (3D). Interfraction bladder volume change was described by quantifying changes in bladder volume with time. Bony setup errors were compared from both XVI and EPI. Results: The bladder boundary was clearly visible on coronal XVI views in nearly all images, allowing accurate 3D treatment verification. In 93.5% of imaged fractions, the clinical target volume was within the planning target volume. Most subjects displayed consistent bladder volumes, but 25% displayed changes that could be predicted from the first three XVIs. Bony setup errors were similar whether calculated from XVI or EPI. Conclusions: Coronal XVI can be used to verify 3D bladder radiotherapy delivery. Image-guided interventions to reduce geographic miss and normal tissue toxicity are feasible with this technology

Increasing the Accuracy of Volume and ADC Delineation for Heterogeneous Tumor on Diffusion-Weighted MRI: Correlation with PET/CT

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Gong, Nan-Jie [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Wong, Chun-Sing, E-mail: drcswong@gmail.com [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Chu, Yiu-Ching [Department of Radiology, Kwong Wah Hospital, Hong Kong (China); Guo, Hua [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing (China); Huang, Bingsheng [Department of Diagnostic Radiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong (China); Chan, Queenie [Philips Healthcare, Hong Kong (China)

2013-10-01

Purpose: To improve the accuracy of volume and apparent diffusion coefficient (ADC) measurements in diffusion-weighted magnetic resonance imaging (MRI), we proposed a method based on thresholding both the b0 images and the ADC maps. Methods and Materials: In 21 heterogeneous lesions from patients with metastatic gastrointestinal stromal tumors (GIST), gross lesion were manually contoured, and corresponding volumes and ADCs were denoted as gross tumor volume (GTV) and gross ADC (ADC{sub g}), respectively. Using a k-means clustering algorithm, the probable high-cellularity tumor tissues were selected based on b0 images and ADC maps. ADC and volume of the tissues selected using the proposed method were denoted as thresholded ADC (ADC{sub thr}) and high-cellularity tumor volume (HCTV), respectively. The metabolic tumor volume (MTV) in positron emission tomography (PET)/computed tomography (CT) was measured using 40% maximum standard uptake value (SUV{sub max}) as the lower threshold, and corresponding mean SUV (SUV{sub mean}) was also measured. Results: HCTV had excellent concordance with MTV according to Pearson's correlation (r=0.984, P<.001) and linear regression (slope = 1.085, intercept = −4.731). In contrast, GTV overestimated the volume and differed significantly from MTV (P=.005). ADC{sub thr} correlated significantly and strongly with SUV{sub mean} (r=−0.807, P<.001) and SUV{sub max} (r=−0.843, P<.001); both were stronger than those of ADC{sub g}. Conclusions: The proposed lesion-adaptive semiautomatic method can help segment high-cellularity tissues that match hypermetabolic tissues in PET/CT and enables more accurate volume and ADC delineation on diffusion-weighted MR images of GIST.

Radiologic measurement of extraocular muscle volumes in patients with Graves' orbitopathy: a review and guideline.

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Bijlsma, Ward R; Mourits, Maarten Ph

2006-06-01

To evaluate and compare techniques for extraocular muscle (EOM) volume measurement and to provide guidelines for future measurements. Systematic review. Existing techniques used to measure extraocular muscle volumes on radiologic scans can be divided into manual outlining, computer assisted and automated segmentation. Both computed tomography (CT) and magnetic resonance (MR) image datasets can be used. On CT scans, one best measures muscle volume using region grow segmentation, accepting an overestimation of true volume by inevitable inclusion of non-muscular tissue. On high resolution MRI scans, single muscles can be outlined manually, but measurements include only part of the muscle due to poor tissue contrast at the orbital apex. Measurement errors can be reduced 3.5% by exact horizontal repositioning. A measured volume change of at least 6-17% is required to demonstrate a significant difference. Currently the best choice for EOM volume measurements on CT images is computer assisted grey value segmentation and on MRI images is manual outlining of individual muscles. Because of the time required and the complexity of the measurements, present EOM volume measurement is as yet only suitable for research purposes.

Parametric Net Influx Rate Images of 68Ga-DOTATOC and 68Ga-DOTATATE: Quantitative Accuracy and Improved Image Contrast.

Science.gov (United States)

Ilan, Ezgi; Sandström, Mattias; Velikyan, Irina; Sundin, Anders; Eriksson, Barbro; Lubberink, Mark

2017-05-01

68 Ga-DOTATOC and 68 Ga-DOTATATE are radiolabeled somatostatin analogs used for the diagnosis of somatostatin receptor-expressing neuroendocrine tumors (NETs), and SUV measurements are suggested for treatment monitoring. However, changes in net influx rate ( K i ) may better reflect treatment effects than those of the SUV, and accordingly there is a need to compute parametric images showing K i at the voxel level. The aim of this study was to evaluate parametric methods for computation of parametric K i images by comparison to volume of interest (VOI)-based methods and to assess image contrast in terms of tumor-to-liver ratio. Methods: Ten patients with metastatic NETs underwent a 45-min dynamic PET examination followed by whole-body PET/CT at 1 h after injection of 68 Ga-DOTATOC and 68 Ga-DOTATATE on consecutive days. Parametric K i images were computed using a basis function method (BFM) implementation of the 2-tissue-irreversible-compartment model and the Patlak method using a descending aorta image-derived input function, and mean tumor K i values were determined for 50% isocontour VOIs and compared with K i values based on nonlinear regression (NLR) of the whole-VOI time-activity curve. A subsample of healthy liver was delineated in the whole-body and K i images, and tumor-to-liver ratios were calculated to evaluate image contrast. Correlation ( R 2 ) and agreement between VOI-based and parametric K i values were assessed using regression and Bland-Altman analysis. Results: The R 2 between NLR-based and parametric image-based (BFM) tumor K i values was 0.98 (slope, 0.81) and 0.97 (slope, 0.88) for 68 Ga-DOTATOC and 68 Ga-DOTATATE, respectively. For Patlak analysis, the R 2 between NLR-based and parametric-based (Patlak) tumor K i was 0.95 (slope, 0.71) and 0.92 (slope, 0.74) for 68 Ga-DOTATOC and 68 Ga-DOTATATE, respectively. There was no bias between NLR and parametric-based K i values. Tumor-to-liver contrast was 1.6 and 2.0 times higher in the parametric

Crossing kingdoms: Using decellularized plants as perfusable tissue engineering scaffolds.

Science.gov (United States)

Gershlak, Joshua R; Hernandez, Sarah; Fontana, Gianluca; Perreault, Luke R; Hansen, Katrina J; Larson, Sara A; Binder, Bernard Y K; Dolivo, David M; Yang, Tianhong; Dominko, Tanja; Rolle, Marsha W; Weathers, Pamela J; Medina-Bolivar, Fabricio; Cramer, Carole L; Murphy, William L; Gaudette, Glenn R

2017-05-01

Despite significant advances in the fabrication of bioengineered scaffolds for tissue engineering, delivery of nutrients in complex engineered human tissues remains a challenge. By taking advantage of the similarities in the vascular structure of plant and animal tissues, we developed decellularized plant tissue as a prevascularized scaffold for tissue engineering applications. Perfusion-based decellularization was modified for different plant species, providing different geometries of scaffolding. After decellularization, plant scaffolds remained patent and able to transport microparticles. Plant scaffolds were recellularized with human endothelial cells that colonized the inner surfaces of plant vasculature. Human mesenchymal stem cells and human pluripotent stem cell derived cardiomyocytes adhered to the outer surfaces of plant scaffolds. Cardiomyocytes demonstrated contractile function and calcium handling capabilities over the course of 21 days. These data demonstrate the potential of decellularized plants as scaffolds for tissue engineering, which could ultimately provide a cost-efficient, "green" technology for regenerating large volume vascularized tissue mass. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Decomposing the Hounsfield unit: probabilistic segmentation of brain tissue in computed tomography.

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Kemmling, A; Wersching, H; Berger, K; Knecht, S; Groden, C; Nölte, I

2012-03-01

The aim of this study was to present and evaluate a standardized technique for brain segmentation of cranial computed tomography (CT) using probabilistic partial volume tissue maps based on a database of high resolution T1 magnetic resonance images (MRI). Probabilistic tissue maps of white matter (WM), gray matter (GM) and cerebrospinal fluid (CSF) were derived from 600 normal brain MRIs (3.0 Tesla, T1-3D-turbo-field-echo) of 2 large community-based population studies (BiDirect and SEARCH Health studies). After partial tissue segmentation (FAST 4.0), MR images were linearly registered to MNI-152 standard space (FLIRT 5.5) with non-linear refinement (FNIRT 1.0) to obtain non-binary probabilistic volume images for each tissue class which were subsequently used for CT segmentation. From 150 normal cerebral CT scans a customized reference image in standard space was constructed with iterative non-linear registration to MNI-152 space. The inverse warp of tissue-specific probability maps to CT space (MNI-152 to individual CT) was used to decompose a CT image into tissue specific components (GM, WM, CSF). Potential benefits and utility of this novel approach with regard to unsupervised quantification of CT images and possible visual enhancement are addressed. Illustrative examples of tissue segmentation in different pathological cases including perfusion CT are presented. Automated tissue segmentation of cranial CT images using highly refined tissue probability maps derived from high resolution MR images is feasible. Potential applications include automated quantification of WM in leukoaraiosis, CSF in hydrocephalic patients, GM in neurodegeneration and ischemia and perfusion maps with separate assessment of GM and WM.

Accumulation of ethoxyquin in the tissue

International Nuclear Information System (INIS)

Kim, H.L.

1991-01-01

Ethoxyquin (EQ) residue levels in the mouse tissue were determined by the HPLC-fluorometric detection method. Mice were given powdered feed containing 0, 0.125, and 0.5% EQ HCl and the EQ residue levels in liver, kidney, lung, and brain tissues were determined after 2, 4, 6, 10, and 14 wk (4 mice/group). The tissue samples were homogenized in 10 volumes (w/v) of acetonitrile-water (7:3, v/v), centrifuged, and the supernatants were stored in a freezer for 2-3 h or until the two layers separated; then the clear upper layers were analyzed. The mean EQ residue levels in the tissue ranged 0.84-4.58 micrograms EQ/g liver and 0.11-0.92 micrograms EQ/g brain. The relative weight of the liver (5.21-7.07% body weight) and the hepatic glutathione level (5.99-7.83 microM GSH/g tissue) of mice that received EQ were significantly higher than those of the controls (4.67-5.05% body weight and 4.30-5.78 microM GSH/g tissue, respectively). The mean hepatic mitochondrial glutathione level of the higher EQ feeding group, following dietary administration of EQ for 14 wk, was approximately twofold (1.68 nM GSH/mg protein) of both the control and the lower EQ feeding groups (0.83 and 0.74 nM GSH/mg protein, respectively)

Semiautomatic regional segmentation to measure orbital fat volumes in thyroid-associated ophthalmopathy. A validation study.

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Comerci, M; Elefante, A; Strianese, D; Senese, R; Bonavolontà, P; Alfano, B; Bonavolontà, B; Brunetti, A

2013-08-01

This study was designed to validate a novel semi-automated segmentation method to measure regional intra-orbital fat tissue volume in Graves' ophthalmopathy. Twenty-four orbits from 12 patients with Graves' ophthalmopathy, 24 orbits from 12 controls, ten orbits from five MRI study simulations and two orbits from a digital model were used. Following manual region of interest definition of the orbital volumes performed by two operators with different levels of expertise, an automated procedure calculated intra-orbital fat tissue volumes (global and regional, with automated definition of four quadrants). In patients with Graves' disease, clinical activity score and degree of exophthalmos were measured and correlated with intra-orbital fat volumes. Operator performance was evaluated and statistical analysis of the measurements was performed. Accurate intra-orbital fat volume measurements were obtained with coefficients of variation below 5%. The mean operator difference in total fat volume measurements was 0.56%. Patients had significantly higher intra-orbital fat volumes than controls (p<0.001 using Student's t test). Fat volumes and clinical score were significantly correlated (p<0.001). The semi-automated method described here can provide accurate, reproducible intra-orbital fat measurements with low inter-operator variation and good correlation with clinical data.

NMR imaging of cell phone radiation absorption in brain tissue

Science.gov (United States)

Gultekin, David H.; Moeller, Lothar

2013-01-01

A method is described for measuring absorbed electromagnetic energy radiated from cell phone antennae into ex vivo brain tissue. NMR images the 3D thermal dynamics inside ex vivo bovine brain tissue and equivalent gel under exposure to power and irradiation time-varying radio frequency (RF) fields. The absorbed RF energy in brain tissue converts into Joule heat and affects the nuclear magnetic shielding and the Larmor precession. The resultant temperature increase is measured by the resonance frequency shift of hydrogen protons in brain tissue. This proposed application of NMR thermometry offers sufficient spatial and temporal resolution to characterize the hot spots from absorbed cell phone radiation in aqueous media and biological tissues. Specific absorption rate measurements averaged over 1 mg and 10 s in the brain tissue cover the total absorption volume. Reference measurements with fiber optic temperature sensors confirm the accuracy of the NMR thermometry. PMID:23248293

Thermal analysis of laser interstitial thermotherapy in ex vivo fibro-fatty tissue using exponential functions

Energy Technology Data Exchange (ETDEWEB)

Salas, Nelson Jr. [Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, PO Box 248294, Coral Gables, FL 33124 (United States); Manns, Fabrice [Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, PO Box 248294, Coral Gables, FL 33124 (United States); Milne, Peter J [Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami School of Medicine, 1638 NW 10th Ave, McKnight Bldg, Miami, FL 33136 (United States); Denham, David B [Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami School of Medicine, 1638 NW 10th Ave, McKnight Bldg, Miami, FL 33136 (United States); Minhaj, Ahmed M [Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, PO Box 248294, Coral Gables, FL 33124 (United States); Parel, Jean-Marie [Biomedical Optics and Laser Laboratory, Department of Biomedical Engineering, University of Miami College of Engineering, PO Box 248294, Coral Gables, FL 33124 (United States); Robinson, David S [Center for Breast Care, St Luke' s Hospital of Kansas City, 4400 Broadway, Suite 509, Kansas City, MO 64111 (United States)

2004-05-07

A therapeutic procedure to treat small, surface breast tumours up to 10 mm in radius plus a 5 mm margin of healthy, surrounding tissue using laser interstitial thermotherapy (LITT) is currently being investigated. The purpose of this study is to analyse and model the thermal and coagulative response of ex vivo fibro-fatty tissue, a model for breast tissue, during experimental laser interstitial thermotherapy at 980 nm. Laser radiation at 980 nm was delivered interstitially through a diffusing tip optical fibre inserted into a fibro-fatty tissue model to produce controlled heating at powers ranging from 3.2 to 8.0 W. Tissue temperature was measured with thermocouples placed at 15 positions around the fibre. The induced coagulation zone was measured on gross anatomical sections. Thermal analysis indicates that a finite sum of exponential functions is an approximate solution to the heat conduction equation that more accurately predicts the time-temperature dependence in tissue prior to carbonization (T < 100 deg. C) during LITT than the traditional model using a single exponential function. Analysis of the ellipsoid coagulation volume induced in tissue indicates that the 980 nm wavelength does not penetrate deep enough in fibro-fatty tissue to produce a desired 30 mm diameter (14.1 x 10{sup 3} mm{sup 3}) coagulation volume without unwanted tissue liquefaction and carbonization.

Objective evaluation of reconstruction methods for quantitative SPECT imaging in the absence of ground truth.

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Jha, Abhinav K; Song, Na; Caffo, Brian; Frey, Eric C

2015-04-13

Quantitative single-photon emission computed tomography (SPECT) imaging is emerging as an important tool in clinical studies and biomedical research. There is thus a need for optimization and evaluation of systems and algorithms that are being developed for quantitative SPECT imaging. An appropriate objective method to evaluate these systems is by comparing their performance in the end task that is required in quantitative SPECT imaging, such as estimating the mean activity concentration in a volume of interest (VOI) in a patient image. This objective evaluation can be performed if the true value of the estimated parameter is known, i.e. we have a gold standard. However, very rarely is this gold standard known in human studies. Thus, no-gold-standard techniques to optimize and evaluate systems and algorithms in the absence of gold standard are required. In this work, we developed a no-gold-standard technique to objectively evaluate reconstruction methods used in quantitative SPECT when the parameter to be estimated is the mean activity concentration in a VOI. We studied the performance of the technique with realistic simulated image data generated from an object database consisting of five phantom anatomies with all possible combinations of five sets of organ uptakes, where each anatomy consisted of eight different organ VOIs. Results indicate that the method provided accurate ranking of the reconstruction methods. We also demonstrated the application of consistency checks to test the no-gold-standard output.

Usefulness of corregistration and post-processing of MR and interictal SPECT images for localization of epileptogenic focus in children – preliminary report

International Nuclear Information System (INIS)

Miśko, Jolanta; Jurkiewicz, Elżbieta; Bekiesińska-Figatowska, Monika; Kamińska, Anna; Bachański, Zbigniew; Chełstowska, Sylwia; Walecki, Jerzy

2011-01-01

Children with focal epilepsy unresponsive to anticonvulsant therapy may become surgical candidates. Inter-ictal SPECT (SPECT-IN) studies demonstrate an area of hypoperfusion within the seizure focus in up to 50% of patients. The goal of this study was to evaluate the usefulness of corregistration of MR and SPECT-IN images for localization of the epileptogenic focus. Brain MRI and SPECT-IN were performed in 20 children (mean age 9.5). We found multifocal (3–6 perfusion deficits in 10 patients) or diffuse perfusion deficits (lobar) in all patients. In fused MR and SPECT images we evaluated average activity in volumes-of-interest (VOIs) outlined in each gray matter region with deficits. Average VOI activity below average total brain activity with at least 15% difference to the mirror VOI in the brain cortex on the opposite side of was considered as “true” perfusion deficit (TPD). In all children from our group, MRI and SPECT-IN image fusion and evaluation of TPD allowed to verify most of multifocal or diffuse deficits: in each of 12 patients we found 1 TPD, in each of 6 patients 2 TPD and in each of 2 patients 3 TPD. In 8 patients with 2 or 3 TPD we used scalp EEG or ictal SPECT for identification of one probable location of epileptogenic focus. In children with refractory focal epilepsy, image fusion of MRI and SPECT-IN with evaluation of TPD has potential clinical utility in localization of epileptogenic focus

Development and proof-of-concept of three-dimensional lung histology volumes

Science.gov (United States)

Mathew, Lindsay; Alabousi, Mostafa; Wheatley, Andrew; Aladl, Usaf; Slipetz, Deborah; Hogg, James C.; Fenster, Aaron; Parraga, Grace

2012-03-01

Most medical imaging is inherently three-dimensional (3D) but for validation of pathological findings, histopathology is commonly used and typically histopathology images are acquired as twodimensional slices with quantitative analysis performed in a single dimension. Histopathology is invasive, labour-intensive, and the analysis cannot be performed in real time, yet it remains the gold standard for the pathological diagnosis and validation of clinical or radiological diagnoses of disease. A major goal worldwide is to improve medical imaging resolution, sensitivity and specificity to better guide therapy and biopsy and to one day delay or replace biopsy. A key limitation however is the lack of tools to directly compare 3D macroscopic imaging acquired in patients with histopathology findings, typically provided in a single dimension (1D) or in two dimensions (2D). To directly address this, we developed methods for 2D histology slice visualization/registration to generate 3D volumes and quantified tissue components in the 3D volume for direct comparison to volumetric micro-CT and clinical CT. We used the elastase-instilled mouse emphysema lung model to evaluate our methods with murine lungs sectioned (5 μm thickness/10 μm gap) and digitized with 2μm in-plane resolution. 3D volumes were generated for wildtype and elastase mouse lung sections after semi-automated registration of all tissue slices. The 1D mean linear intercept (Lm) for wildtype (WT) (47.1 μm +/- 9.8 μm) and elastase mouse lung (64.5 μm +/- 14.0 μm) was significantly different (p<.001). We also generated 3D measurements based on tissue and airspace morphometry from the 3D volumes and all of these were significantly different (p<.0001) when comparing elastase and WT mouse lung. The ratio of the airspace-to-lung volume for the entire lung volume was also significantly and strongly correlated with Lm.

Plasma volume changes during hypoglycaemia: the effect of arterial blood sampling

DEFF Research Database (Denmark)

Hilsted, J; Bendtsen, F; Christensen, N J

1990-01-01

To investigate whether previously reported changes in venous blood volume and composition induced by acute hypoglycaemia in humans are representative for the entire body we measured erythrocyte 51Cr content, haematocrit, plasma volume, intravascular albumin content and transcapillary escape rate...... hypoglycaemia. The magnitude of the changes in arterial and venous blood were not significantly different. These results indicate that the above changes in blood volume and composition are whole-body phenomena: furthermore, the major part of the changes are likely to occur in tissues other than upper extremity...

Correlating lesion size and location to deficits after ischemic stroke: the influence of accounting for altered peri-necrotic tissue and incidental silent infarcts

Directory of Open Access Journals (Sweden)

Black Sandra E

2010-01-01

Full Text Available Abstract Background Investigators frequently quantify and evaluate the location and size of stroke lesions to help uncover cerebral anatomical correlates of deficits observed after first-ever stroke. However, it is common to discover silent infarcts such as lacunes in patients identified clinically as 'first-ever' stroke, and it is unclear if including these incidental findings may impact lesion-based investigations of brain-behaviour relationships. There is also debate concerning how to best define the boundaries of necrotic stroke lesions that blend in an ill-defined way into surrounding tissue, as it is unclear whether including this altered peri-necrotic tissue region may influence studies of brain-behaviour relationships. Therefore, for patients with clinically overt stroke, we examined whether including altered peri-necrotic tissue and incidental silent strokes influenced either lesion volume correlations with a measure of sensorimotor impairment or the anatomical localization of this impairment established using subtraction lesion analysis. Methods Chronic stroke lesions of 41 patients were manually traced from digital T1-MRI to sequentially include the: necrotic lesion core, altered peri-necrotic tissue, silent lesions in the same hemisphere as the index lesion, and silent lesions in the opposite hemisphere. Lesion volumes for each region were examined for correlation with motor impairment scores, and subtraction analysis was used to highlight anatomical lesion loci associated with this deficit. Results For subtraction lesion analysis, including peri-necrotic tissue resulted in a larger region of more frequent damage being seen in the basal ganglia. For correlational analysis, only the volume of the lesion core was significantly associated with motor impairment scores (r = -0.35, p = 0.025. In a sub-analysis of patients with small subcortical index lesions, adding silent lesions in the opposite hemisphere to the volume of the index

Motion-specific internal target volumes for FDG-avid mediastinal and hilar lymph nodes

International Nuclear Information System (INIS)

Lamb, James M.; Robinson, Clifford G.; Bradley, Jeffrey D.; Low, Daniel A.

2013-01-01

Background and purpose: To quantify the benefit of motion-specific internal target volumes for FDG-avid mediastinal and hilar lymph nodes generated using 4D-PET, vs. conventional internal target volumes generated using non-respiratory gated PET and 4D-CT scans. Materials and methods: Five patients with FDG-avid tumors metastatic to 11 hilar or mediastinal lymph nodes were imaged with respiratory-correlated FDG-PET (4D-PET) and 4D-CT. FDG-avid nodes were contoured by a radiation oncologist in two ways. Standard-of-care volumes were contoured using conventional un-gated PET, 4D-CT, and breath-hold CT. A second, motion-specific, set of volumes were contoured using 4D-PET.Contours based on 4D-PET corresponded directly to an internal target volume (ITV 4D ), whereas contours based on un-gated PET were expanded by a series of exploratory isotropic margins (from 5 to 13 mm) based on literature recommendations on lymph node motion to form internal target volumes (ITV 3D ). Results: A 13 mm expansion of the un-gated PET nodal volume was needed to cover the ITV 4D for 10 of 11 nodes studied. The ITV 3D based on a 13 mm expansion included on average 45 cm 3 of tissue that was not included in the ITV 4D . Conclusions: Motion-specific lymph-node internal target volumes generated from 4D-PET imaging could be used to improve accuracy and/or reduce normal-tissue irradiation compared to the standard-of-care un-gated PET based internal target volumes

Brain putamen volume changes in newly-diagnosed patients with obstructive sleep apnea

Directory of Open Access Journals (Sweden)

Rajesh Kumar

2014-01-01

Full Text Available Obstructive sleep apnea (OSA is accompanied by cognitive, motor, autonomic, learning, and affective abnormalities. The putamen serves several of these functions, especially motor and autonomic behaviors, but whether global and specific sub-regions of that structure are damaged is unclear. We assessed global and regional putamen volumes in 43 recently-diagnosed, treatment-naïve OSA (age, 46.4 ± 8.8 years; 31 male and 61 control subjects (47.6 ± 8.8 years; 39 male using high-resolution T1-weighted images collected with a 3.0-Tesla MRI scanner. Global putamen volumes were calculated, and group differences evaluated with independent samples t-tests, as well as with analysis of covariance (covariates; age, gender, and total intracranial volume. Regional differences between groups were visualized with 3D surface morphometry-based group ratio maps. OSA subjects showed significantly higher global putamen volumes, relative to controls. Regional analyses showed putamen areas with increased and decreased tissue volumes in OSA relative to control subjects, including increases in caudal, mid-dorsal, mid-ventral portions, and ventral regions, while areas with decreased volumes appeared in rostral, mid-dorsal, medial-caudal, and mid-ventral sites. Global putamen volumes were significantly higher in the OSA subjects, but local sites showed both higher and lower volumes. The appearance of localized volume alterations points to differential hypoxic or perfusion action on glia and other tissues within the structure, and may reflect a stage in progression of injury in these newly-diagnosed patients toward the overall volume loss found in patients with chronic OSA. The regional changes may underlie some of the specific deficits in motor, autonomic, and neuropsychologic functions in OSA.

Vascular and metabolic effects of adrenaline in adipose tissue in type 2 diabetes

DEFF Research Database (Denmark)

Tobin, L; Simonsen, L; Galbo, H

2012-01-01

Objective:The aim was to investigate adipose tissue vascular and metabolic effects of an adrenaline infusion in vivo in subjects with and without type 2 diabetes mellitus (T2DM).Design:Clinical intervention study with 1-h intravenous adrenaline infusion.Subjects:Eight male overweight T2DM subjects...... and eight male weight-matched, non-T2DM subjects were studied before, during and after an 1-h intravenous adrenaline infusion. Adipose tissue blood flow (ATBF) was determined by Xenon wash-out technique, and microvascular volume in the adipose tissue was studied by contrast-enhanced ultrasound imaging...... infusion. One hour post adrenaline, ATBF was still increased in overweight T2DM subjects. Adrenaline increased microvascular volume in non-T2DM subjects while this response was impaired in overweight T2DM subjects. Adrenaline-induced increase in lipolysis was similar in both groups, but NEFA output from...

Increased intracranial volume in Parkinson's disease

DEFF Research Database (Denmark)

Krabbe, Katja; Karlsborg, Merete; Hansen, Andreas

2005-01-01

Parkinson's disease (PD) and multiple system atrophy (MSA) are neurodegenerative diseases that can be difficult to diagnose and distinguish from each other. STUDY AIMS AND METHODS: Patients with PD and MSA and controls were studied with magnetic resonance imaging (MRI) using tissue segmentation a...... and outlining of regions in order to identify regional volume changes that might be useful in the diagnosis of the two diseases....

Analysis of Partial Volume Effects on Arterial Input Functions Using Gradient Echo: A Simulation Study

DEFF Research Database (Denmark)

Kjølby, Birgitte Fuglsang; Mikkelsen, Irene Klærke; Pedersen, Michael

2009-01-01

of an AIF voxel including the relaxation properties of blood and tissue. Artery orientations parallel and perpendicular to the main magnetic field were investigated and AIF voxels were modeled to either include or be situated close to a large artery. The impact of partial volume effects on quantitative...... perfusion metrics was investigated for the gradient echo pulse sequence at 1.5 T and 3.0 T. It is shown that the tissue contribution broadens and introduces fluctuations in the AIF. Furthermore, partial volume effects bias perfusion metrics in a nonlinear fashion, compromising quantitative perfusion...

MRI analysis on soft tissue around upper airway in obese adolescent patients with obstructive sleep apnea syndrome

International Nuclear Information System (INIS)

Zhang Zhengjiao; Yuan Haibo; Peng Liping; Li Dan; Hua Shucheng

2012-01-01

Objective: To investigate the correlation of soft tissue structure of upper airway with the pathogenesis of obstructive sleep apnea syndrome (OSAS) in adolescents age group by analyzing magnetic resonance imaging (MRI) of upper airway. Methods: The subjects were divided into obese OSAS, obese controls and normal weight controls groups according to the results from polysomnography and body mass index measurements; Upper airway was scanned by MRI sagittally and axially; upper airway at all levels and soft tissue was analyzed by Amira Medical image analysis system. Results: Tongue volumes in obese OSAS and obese controls were significantly greater than that in normal weight controls (P<0.05); tonsil and adenoid volumes in obese OSAS were significantly higher than those in two control groups (P<0.05 or P<0.001), but no significant difference was found between two control groups. The volumes of lateral pharyngeal wall in obese OSAS were higher than those in obese controls and normal weight controls (P<0.05 or P<0.001), and they were higher in obese controls compared with normal weight controls (P<0.05). In obese OSAS group, positive correlations were found between volumes of lateral pharyngeal wall and apnea/hypopnea index (AHI) (r=0.879, P<0.01), as well volumes of tonsils and AHI (r=0.824, P<0.01). Conclusion: Obesity can increase the soft tissue volumes around upper airway, there by increase the upper airway obstruction; lateral pharyngeal wall and adenoid volumes play major roles in evaluating the severity of OSAS in adolescents. (authors)

Using deep learning to segment breast and fibroglandular tissue in MRI volumes

NARCIS (Netherlands)

Dalmis, M.U.; Litjens, G.J.; Holland, K.; Setio, A.A.A.; Mann, R.M.; Karssemeijer, N.; Gubern Merida, A.

2017-01-01

PURPOSE: Automated segmentation of breast and fibroglandular tissue (FGT) is required for various computer-aided applications of breast MRI. Traditional image analysis and computer vision techniques, such atlas, template matching, or, edge and surface detection, have been applied to solve this task.

Nuclear fragmentation and the number of particle tracks in tissue

International Nuclear Information System (INIS)

Ponomarev, A. L.; Cucinotta, F. A.

2006-01-01

For high energy nuclei, the number of particle tracks per cell is modified by local nuclear reactions that occur, with large fluctuations expected for heavy ion tracks. Cells near the interaction site of a reaction will experience a much higher number of tracks than estimated by the average fluence. Two types of reaction products are possible and occur in coincidence; projectile fragments, which generally have smaller charge and similar velocity to that of the projectile, and target fragments, which are produced from the fragmentation of the nuclei of water atoms or other cellular constituents with low velocity. In order to understand the role of fragmentation in biological damage a new model of human tissue irradiated by heavy ions was developed. A box of the tissue is modelled with periodic boundary conditions imposed, which extrapolates the technique to macroscopic volumes of tissue. The cross sections for projectile and target fragmentation products are taken from the quantum multiple scattering fragmentation code previously developed at NASA Johnson Space Center. Statistics of fragmentation pathways occurring in a cell monolayer, as well as in a small volume of 10 x 10 x 10 cells are given. A discussion on approaches to extend the model to describe spatial distributions of inactivated or other cell damage types, as well as highly organised tissues of multiple cell types, is presented. (authors)

Microscopic histological characteristics of soft tissue sarcomas: analysis of tissue features and electrical resistance.

Science.gov (United States)

Tosi, A L; Campana, L G; Dughiero, F; Forzan, M; Rastrelli, M; Sieni, E; Rossi, C R

2017-07-01

Tissue electrical conductivity is correlated with tissue characteristics. In this work, some soft tissue sarcomas (STS) excised from patients have been evaluated in terms of histological characteristics (cell size and density) and electrical resistance. The electrical resistance has been measured using the ex vivo study on soft tissue tumors electrical characteristics (ESTTE) protocol proposed by the authors in order to study electrical resistance of surgical samples excised by patients in a fixed measurement setup. The measurement setup includes a voltage pulse generator (700 V, 100 µs long at 5 kHz, period 200 µs) and an electrode with 7 needles, 20 mm-long, with the same distance arranged in a fixed hexagonal geometry. In the ESTTE protocol, the same voltage pulse sequence is applied to each different tumor mass and the corresponding resistance has been evaluated from voltage and current recorded by the equipment. For each tumor mass, a histological sample of the volume treated by means of voltage pulses has been taken for histological analysis. Each mass has been studied in order to identify the sarcoma type. For each histological sample, an image at 20× or 40× of magnification was acquired. In this work, the electrical resistance measured for each tumor has been correlated with tissue characteristics like the type, size and density of cells. This work presents a preliminary study to explore possible correlations between tissue characteristics and electrical resistance of STS. These results can be helpful to adjust the pulse voltage intensity in order to improve the electrochemotherapy efficacy on some histotype of STS.

Resonance sensor measurements of stiffness variations in prostate tissue in vitro--a weighted tissue proportion model.

Science.gov (United States)

Jalkanen, Ville; Andersson, Britt M; Bergh, Anders; Ljungberg, Börje; Lindahl, Olof A

2006-12-01

Prostate cancer is the most common type of cancer in men in Europe and the US. The methods to detect prostate cancer are still precarious and new techniques are needed. A piezoelectric transducer element in a feedback system is set to vibrate with its resonance frequency. When the sensor element contacts an object a change in the resonance frequency is observed, and this feature has been utilized in sensor systems to describe physical properties of different objects. For medical applications it has been used to measure stiffness variations due to various patho-physiological conditions. In this study the sensor's ability to measure the stiffness of prostate tissue, from two excised prostatectomy specimens in vitro, was analysed. The specimens were also subjected to morphometric measurements, and the sensor parameter was compared with the morphology of the tissue with linear regression. In the probe impression interval 0.5-1.7 mm, the maximum R(2) > or = 0.60 (p sensor was pressed, the greater, i.e., deeper, volume it sensed. Tissue sections deeper in the tissue were assigned a lower mathematical weighting than sections closer to the sensor probe. It is concluded that cancer increases the measured stiffness as compared with healthy glandular tissue, but areas with predominantly stroma or many stones could be more difficult to differ from cancer.

Aircraft Trajectories Computation-Prediction-Control (La Trajectoire de l’Avion Calcul-Prediction-Controle). Volume 2

Science.gov (United States)

1990-05-01

the turning aircraft passes ahead of its straight-line companion , possibly with a vertical spacing of several hundred feet. Between 40 secs. and 20... Chef du contr8le d’approche et d’a6rodrome (tour) At Bruxelles-National ** Chef du contr6le At Bruxelles-National 20F-9 RE RCIEMENTS Nous tenons A...Voies adriennes (Belgique), compdtent en contr6le en route et en contr6le d’approche et actuellemont chef du Service de contr8le d’approche-tour et

Potassium titanyl phosphate laser tissue ablation: development and experimental validation of a new numerical model.

Science.gov (United States)

Elkhalil, Hossam; Akkin, Taner; Pearce, John; Bischof, John

2012-10-01

The photoselective vaporization of prostate (PVP) green light (532 nm) laser is increasingly being used as an alternative to the transurethral resection of prostate (TURP) for treatment of benign prostatic hyperplasia (BPH) in older patients and those who are poor surgical candidates. In order to achieve the goals of increased tissue removal volume (i.e., "ablation" in the engineering sense) and reduced collateral thermal damage during the PVP green light treatment, a two dimensional computational model for laser tissue ablation based on available parameters in the literature has been developed and compared to experiments. The model is based on the control volume finite difference and the enthalpy method with a mechanistically defined energy necessary to ablate (i.e., physically remove) a volume of tissue (i.e., energy of ablation E(ab)). The model was able to capture the general trends experimentally observed in terms of ablation and coagulation areas, their ratio (therapeutic index (TI)), and the ablation rate (AR) (mm(3)/s). The model and experiment were in good agreement at a smaller working distance (WD) (distance from the tissue in mm) and a larger scanning speed (SS) (laser scan speed in mm/s). However, the model and experiment deviated somewhat with a larger WD and a smaller SS; this is most likely due to optical shielding and heat diffusion in the laser scanning direction, which are neglected in the model. This model is a useful first step in the mechanistic prediction of PVP based BPH laser tissue ablation. Future modeling efforts should focus on optical shielding, heat diffusion in the laser scanning direction (i.e., including 3D effects), convective heat losses at the tissue boundary, and the dynamic optical, thermal, and coagulation properties of BPH tissue.

Avoiding Complications in Bone and Soft Tissue Ablation

International Nuclear Information System (INIS)

Kurup, A. Nicholas; Schmit, Grant D.; Morris, Jonathan M.; Atwell, Thomas D.; Schmitz, John J.; Weisbrod, Adam J.; Woodrum, David A.; Eiken, Patrick W.; Callstrom, Matthew R.

2017-01-01

As with percutaneous ablation of tumors in the liver, lungs, and kidneys, ablation of bone and non-visceral soft tissue tumors carries risk, primarily from collateral damage to vital structures in proximity to the target tumor. Certain risks are of particular interest when ablating bone and non-visceral soft tissue tumors, namely neural or skin injury, bowel injury, fracture, and gas embolism from damaged applicators. Ablation of large volume tumors also carries special risk. Many techniques may be employed by the interventional radiologist to minimize complications when treating tumors in the musculoskeletal system. These methods include those to depict, displace, or monitor critical structures. Thus, measures to provide thermoprotection may be active, such as careful ablation applicator placement and use of various displacement techniques, as well as passive, including employment of direct temperature, radiographic, or neurophysiologic monitoring techniques. Cementoplasty should be considered in certain skeletal locations at risk of fracture. Patients treated with large volume tumors should be monitored for renal dysfunction and properly hydrated. Finally, ablation applicators should be cautiously placed in the constrained environment of intact bone.

Avoiding Complications in Bone and Soft Tissue Ablation

Energy Technology Data Exchange (ETDEWEB)

Kurup, A. Nicholas, E-mail: kurup.anil@mayo.edu; Schmit, Grant D., E-mail: schmit.grant@mayo.edu; Morris, Jonathan M., E-mail: morris.jonathan@mayo.edu; Atwell, Thomas D., E-mail: atwell.thomas@mayo.edu; Schmitz, John J., E-mail: schmitz.john@mayo.edu; Weisbrod, Adam J., E-mail: weisbrod.adam@mayo.edu; Woodrum, David A., E-mail: woodrum.david@mayo.edu; Eiken, Patrick W., E-mail: eiken.patrick@mayo.edu; Callstrom, Matthew R., E-mail: callstrom.matthew@mayo.edu [Mayo Clinic, Department of Radiology (United States)

2017-02-15

As with percutaneous ablation of tumors in the liver, lungs, and kidneys, ablation of bone and non-visceral soft tissue tumors carries risk, primarily from collateral damage to vital structures in proximity to the target tumor. Certain risks are of particular interest when ablating bone and non-visceral soft tissue tumors, namely neural or skin injury, bowel injury, fracture, and gas embolism from damaged applicators. Ablation of large volume tumors also carries special risk. Many techniques may be employed by the interventional radiologist to minimize complications when treating tumors in the musculoskeletal system. These methods include those to depict, displace, or monitor critical structures. Thus, measures to provide thermoprotection may be active, such as careful ablation applicator placement and use of various displacement techniques, as well as passive, including employment of direct temperature, radiographic, or neurophysiologic monitoring techniques. Cementoplasty should be considered in certain skeletal locations at risk of fracture. Patients treated with large volume tumors should be monitored for renal dysfunction and properly hydrated. Finally, ablation applicators should be cautiously placed in the constrained environment of intact bone.

SU-F-J-74: High Z Geometric Integrity and Beam Hardening Artifact Assessment Using a Retrospective Metal Artifact Reduction (MAR) Reconstruction Algorithm

Energy Technology Data Exchange (ETDEWEB)

Woods, K; DiCostanzo, D; Gupta, N [Ohio State University Columbus, OH (United States)

2016-06-15

Purpose: To test the efficacy of a retrospective metal artifact reduction (MAR) reconstruction algorithm for a commercial computed tomography (CT) scanner for radiation therapy purposes. Methods: High Z geometric integrity and artifact reduction analysis was performed with three phantoms using General Electric’s (GE) Discovery CT. The three phantoms included: a Computerized Imaging Reference Systems (CIRS) electron density phantom (Model 062) with a 6.5 mm diameter titanium rod insert, a custom spine phantom using Synthes Spine hardware submerged in water, and a dental phantom with various high Z fillings submerged in water. Each phantom was reconstructed using MAR and compared against the original scan. Furthermore, each scenario was tested using standard and extended Hounsfield Unit (HU) ranges. High Z geometric integrity was performed using the CIRS phantom, while the artifact reduction was performed using all three phantoms. Results: Geometric integrity of the 6.5 mm diameter rod was slightly overestimated for non-MAR scans for both standard and extended HU. With MAR reconstruction, the rod was underestimated for both standard and extended HU. For artifact reduction, the mean and standard deviation was compared in a volume of interest (VOI) in the surrounding material (water and water equivalent material, ∼0HU). Overall, the mean value of the VOI was closer to 0 HU for the MAR reconstruction compared to the non-MAR scan for most phantoms. Additionally, the standard deviations for all phantoms were greatly reduced using MAR reconstruction. Conclusion: GE’s MAR reconstruction algorithm improves image quality with the presence of high Z material with minimal degradation of its geometric integrity. High Z delineation can be carried out with proper contouring techniques. The effects of beam hardening artifacts are greatly reduced with MAR reconstruction. Tissue corrections due to these artifacts can be eliminated for simple high Z geometries and greatly

SU-F-J-74: High Z Geometric Integrity and Beam Hardening Artifact Assessment Using a Retrospective Metal Artifact Reduction (MAR) Reconstruction Algorithm

International Nuclear Information System (INIS)

Woods, K; DiCostanzo, D; Gupta, N

2016-01-01

Purpose: To test the efficacy of a retrospective metal artifact reduction (MAR) reconstruction algorithm for a commercial computed tomography (CT) scanner for radiation therapy purposes. Methods: High Z geometric integrity and artifact reduction analysis was performed with three phantoms using General Electric’s (GE) Discovery CT. The three phantoms included: a Computerized Imaging Reference Systems (CIRS) electron density phantom (Model 062) with a 6.5 mm diameter titanium rod insert, a custom spine phantom using Synthes Spine hardware submerged in water, and a dental phantom with various high Z fillings submerged in water. Each phantom was reconstructed using MAR and compared against the original scan. Furthermore, each scenario was tested using standard and extended Hounsfield Unit (HU) ranges. High Z geometric integrity was performed using the CIRS phantom, while the artifact reduction was performed using all three phantoms. Results: Geometric integrity of the 6.5 mm diameter rod was slightly overestimated for non-MAR scans for both standard and extended HU. With MAR reconstruction, the rod was underestimated for both standard and extended HU. For artifact reduction, the mean and standard deviation was compared in a volume of interest (VOI) in the surrounding material (water and water equivalent material, ∼0HU). Overall, the mean value of the VOI was closer to 0 HU for the MAR reconstruction compared to the non-MAR scan for most phantoms. Additionally, the standard deviations for all phantoms were greatly reduced using MAR reconstruction. Conclusion: GE’s MAR reconstruction algorithm improves image quality with the presence of high Z material with minimal degradation of its geometric integrity. High Z delineation can be carried out with proper contouring techniques. The effects of beam hardening artifacts are greatly reduced with MAR reconstruction. Tissue corrections due to these artifacts can be eliminated for simple high Z geometries and greatly

Motion compensation in extremity cone-beam CT using a penalized image sharpness criterion

Science.gov (United States)

Sisniega, A.; Stayman, J. W.; Yorkston, J.; Siewerdsen, J. H.; Zbijewski, W.

2017-05-01

Cone-beam CT (CBCT) for musculoskeletal imaging would benefit from a method to reduce the effects of involuntary patient motion. In particular, the continuing improvement in spatial resolution of CBCT may enable tasks such as quantitative assessment of bone microarchitecture (0.1 mm-0.2 mm detail size), where even subtle, sub-mm motion blur might be detrimental. We propose a purely image based motion compensation method that requires no fiducials, tracking hardware or prior images. A statistical optimization algorithm (CMA-ES) is used to estimate a motion trajectory that optimizes an objective function consisting of an image sharpness criterion augmented by a regularization term that encourages smooth motion trajectories. The objective function is evaluated using a volume of interest (VOI, e.g. a single bone and surrounding area) where the motion can be assumed to be rigid. More complex motions can be addressed by using multiple VOIs. Gradient variance was found to be a suitable sharpness metric for this application. The performance of the compensation algorithm was evaluated in simulated and experimental CBCT data, and in a clinical dataset. Motion-induced artifacts and blurring were significantly reduced across a broad range of motion amplitudes, from 0.5 mm to 10 mm. Structure similarity index (SSIM) against a static volume was used in the simulation studies to quantify the performance of the motion compensation. In studies with translational motion, the SSIM improved from 0.86 before compensation to 0.97 after compensation for 0.5 mm motion, from 0.8 to 0.94 for 2 mm motion and from 0.52 to 0.87 for 10 mm motion (~70% increase). Similar reduction of artifacts was observed in a benchtop experiment with controlled translational motion of an anthropomorphic hand phantom, where SSIM (against a reconstruction of a static phantom) improved from 0.3 to 0.8 for 10 mm motion. Application to a clinical dataset of a lower extremity showed dramatic reduction

Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations

Directory of Open Access Journals (Sweden)

Christopher M. Mahoney

2018-05-01

Full Text Available Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

Current Therapeutic Strategies for Adipose Tissue Defects/Repair Using Engineered Biomaterials and Biomolecule Formulations.

Science.gov (United States)

Mahoney, Christopher M; Imbarlina, Cayla; Yates, Cecelia C; Marra, Kacey G

2018-01-01

Tissue engineered scaffolds for adipose restoration/repair has significantly evolved in recent years. Patients requiring soft tissue reconstruction, caused by defects or pathology, require biomaterials that will restore void volume with new functional tissue. The gold standard of autologous fat grafting (AFG) is not a reliable option. This review focuses on the latest therapeutic strategies for the treatment of adipose tissue defects using biomolecule formulations and delivery, and specifically engineered biomaterials. Additionally, the clinical need for reliable off-the-shelf therapies, animal models, and challenges facing current technologies are discussed.

Automatic intrinsic cardiac and respiratory gating from cone-beam CT scans of the thorax region

Science.gov (United States)

Hahn, Andreas; Sauppe, Sebastian; Lell, Michael; Kachelrieß, Marc

2016-03-01

We present a new algorithm that allows for raw data-based automated cardiac and respiratory intrinsic gating in cone-beam CT scans. It can be summarized in three steps: First, a median filter is applied to an initially reconstructed volume. The forward projection of this volume contains less motion information and is subtracted from the original projections. This results in new raw data that contain only moving and not static anatomy like bones, that would otherwise impede the cardiac or respiratory signal acquisition. All further steps are applied to these modified raw data. Second, the raw data are cropped to a region of interest (ROI). The ROI in the raw data is determined by the forward projection of a binary volume of interest (VOI) that includes the diaphragm for respiratory gating and most of the edge of the heart for cardiac gating. Third, the mean gray value in this ROI is calculated for every projection and the respiratory/cardiac signal is acquired using a bandpass filter. Steps two and three are carried out simultaneously for 64 or 1440 overlapping VOI inside the body for the respiratory or cardiac signal respectively. The signals acquired from each ROI are compared and the most consistent one is chosen as the desired cardiac or respiratory motion signal. Consistency is assessed by the standard deviation of the time between two maxima. The robustness and efficiency of the method is evaluated using simulated and measured patient data by computing the standard deviation of the mean signal difference between the ground truth and the intrinsic signal.

Diffusion tensor imaging correlates with lesion volume in cerebral hemisphere infarctions

International Nuclear Information System (INIS)

Rossi, Maija E; Jason, Eeva; Marchesotti, Silvia; Dastidar, Prasun; Ollikainen, Jyrki; Soimakallio, Seppo

2010-01-01

Both a large lesion volume and abnormalities in diffusion tensor imaging are independently associated with a poor prognosis after cerebral infarctions. Therefore, we assume that they are associated. This study assessed the associations between lesion volumes and diffusion tensor imaging in patients with a right-sided cerebral infarction. The lesion volumes of 33 patients (age 65.9 ± 8.7, 26 males and 7 females) were imaged using computed tomography (CT) in the acute phase (within 3-4 hours) and magnetic resonance imaging (MRI) in the chronic phase (follow-up at 12 months, with a range of 8-27 months). The chronic-phase fractional anisotropy (FA) and mean diffusivity (MD) values were measured at the site of the infarct and selected white matter tracts. Neurological tests in both the acute and chronic phases, and DTI lateralization were assessed with the Wilcoxon signed-rank test. The effects of thrombolytic therapy (n = 10) were assessed with the Mann-Whitney U test. The correlations between the measured parameters were analysed with Spearman's rho correlation. Bonferroni post-hoc correction was used to compensate for the familywise error rate in multiple comparisons. Several MD values in the right hemisphere correlated positively and FA values negatively with the lesion volumes. These correlations included both lesion area and healthy tissue. The results of the mini-mental state examination and the National Institutes of Health Stroke Scale also correlated with the lesion volume. A larger infarct volume is associated with more pronounced tissue modifications in the chronic stage as observed with the MD and FA alterations

Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage

NARCIS (Netherlands)

Rutgers, M.; van Pelt, M.J.; Dhert, W.J.A.; Creemers, L.B.; Saris, D.B.F.

2010-01-01

Osteoarthritis and Cartilage Volume 18, Issue 1, January 2010, Pages 12-23 -------------------------------------------------------------------------------- Review Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage M. Rutgers†, M.J.P. van Pelt†,

Laktaattimääritys kemian analysaattorilla ja verikaasuanalysaattorilla

OpenAIRE

Raatikainen, Jenni

2015-01-01

Normaalisti hapellisissa oloissa glukoosi hajoaa aineenvaihdunnan seurauksena solujen käyttöön vapautuvaksi energiaksi, vedeksi ja hiilidioksidiksi. Hapettomissa oloissa glukoosi kuitenkin hajoaa laktaatiksi. Sydämen, verenkierron tai keuhkojen vakava toimintahäiriö voi aiheuttaa kudosten vähentynyttä hapensaantia, joka voi johtaa anaerobiseen aineenvaihduntaan soluissa ja laktaatin muodostumiseen. Tämän vuoksi laktaatti on yleinen tutkimus esimerkiksi teho-osastolla. Laktaattia voi muodostua...

Autoregressive moving average (ARMA) model applied to quantification of cerebral blood flow using dynamic susceptibility contrast-enhanced magnetic resonance imaging

International Nuclear Information System (INIS)

Murase, Kenya; Yamazaki, Youichi; Shinohara, Masaaki

2003-01-01

The purpose of this study was to investigate the feasibility of the autoregressive moving average (ARMA) model for quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) in comparison with deconvolution analysis based on singular value decomposition (DA-SVD). Using computer simulations, we generated a time-dependent concentration of the contrast agent in the volume of interest (VOI) from the arterial input function (AIF) modeled as a gamma-variate function under various CBFs, cerebral blood volumes and signal-to-noise ratios (SNRs) for three different types of residue function (exponential, triangular, and box-shaped). We also considered the effects of delay and dispersion in AIF. The ARMA model and DA-SVD were used to estimate CBF values from the simulated concentration-time curves in the VOI and AIFs, and the estimated values were compared with the assumed values. We found that the CBF value estimated by the ARMA model was more sensitive to the SNR and the delay in AIF than that obtained by DA-SVD. Although the ARMA model considerably overestimated CBF at low SNRs, it estimated the CBF more accurately than did DA-SVD at high SNRs for the exponential or triangular residue function. We believe this study will contribute to an understanding of the usefulness and limitations of the ARMA model when applied to quantification of CBF with DSC-MRI. (author)

Detection of Amide and Aromatic Proton Resonances of Human Brain Metabolites Using Localized Correlated Spectroscopy Combined with Two Different Water Suppression Schemes

Directory of Open Access Journals (Sweden)

Rajakumar Nagarajan

2010-01-01

Full Text Available The purpose of the study was to demonstrate the J-coupling connectivity network between the amide, aliphatic, and aromatic proton resonances of metabolites in human brain using two-dimensional (2D localized correlated spectroscopy (L-COSY. Two different global water suppression techniques were combined with L-COSY, one before and another after localizing the volume of interest (VOI. Phantom solutions containing several cerebral metabolites at physiological concentrations were evaluated initially for sequence optimization. Nine healthy volunteers were scanned using a 3T whole body MRI scanner. The VOI for 2D L-COSY was placed in the right occipital white/gray matter region. The 2D cross and diagonal peak volumes were measured for several metabolites such as N-acetyl aspartate (NAA, creatine (Cr, free choline (Ch, glutamate/glutamine (Glx, aspartate (Asp, myo-inositol (mI, GABA, glutathione (GSH, phosphocholine (PCh, phosphoethanolamine (PE, tyrosine (Tyr, lactate (Lac, macromolecules (MM and homocarnosine (Car. Using the pre-water suppression technique with L-COSY, the above mentioned metabolites were clearly identifiable and the relative ratios of metabolites were calculated. In addition to detecting multitude of aliphatic resonances in the high field region, we have demonstrated that the amide and aromatic resonances can also be detected using 2D L-COSY by pre water suppression more reliably than the post-water suppression.

Radiological and pathological response following pre-operative radiotherapy for soft-tissue sarcoma

International Nuclear Information System (INIS)

Roberge, David; Skamene, Tanya; Nahal, Ayoub; Turcotte, Robert E.; Powell, Tom; Freeman, Carolyn

2010-01-01

Purpose: To report radiological and pathological response to neo-adjuvant radiotherapy for extremity and trunk soft-tissue sarcomas. Materials/methods: Fifty patients were identified retrospectively. All patients had MRI imaging pre and post neo-adjuvant external beam radiotherapy. Tumor volumes were measured in 3D on T1 Gadolinium enhanced sequences. Pathological treatment response was quantified in terms of percentage of treatment-related necrosis for each case. Results: Histopathologic responses to treatment varied from 0% to 100%. The median pathological treatment response was 67.5% for low-grade sarcomas and 50% for high-grade sarcomas. The median decrease in tumor volume was 13.8% for non-myxoid low-grade sarcomas, 82.1% for myxoid liposarcomas and <1% for high-grade sarcomas. A partial response on MRI (volume reduction ≥ 50%) was highly predictive of a good pathological response (p < 0.001). Patients with stable disease on imaging or volumetric progression had wide ranging pathological responses. Conclusions: Soft-tissue sarcomas show significant pathological treatment responses in the form of hyaline fibrosis, necrosis and granulation tissue. Despite this, there is minimal early volumetric response to radiation, especially for high-grade tumors. Although radiological partial response was predictive of pathological response, the significance of radiological progression was unclear. Myxoid liposarcoma tumor type was predictive of both pathological and radiological tumor response.

Data-driven classification of ventilated lung tissues using electrical impedance tomography

International Nuclear Information System (INIS)

Gómez-Laberge, Camille; Hogan, Matthew J; Elke, Gunnar; Weiler, Norbert; Frerichs, Inéz; Adler, Andy

2011-01-01

Current methods for identifying ventilated lung regions utilizing electrical impedance tomography images rely on dividing the image into arbitrary regions of interest (ROI), manually delineating ROI, or forming ROI with pixels whose signal properties surpass an arbitrary threshold. In this paper, we propose a novel application of a data-driven classification method to identify ventilated lung ROI based on forming k clusters from pixels with correlated signals. A standard first-order model for lung mechanics is then applied to determine which ROI correspond to ventilated lung tissue. We applied the method in an experimental study of 16 mechanically ventilated swine in the supine position, which underwent changes in positive end-expiratory pressure (PEEP) and fraction of inspired oxygen (F I O 2 ). In each stage of the experimental protocol, the method performed best with k = 4 and consistently identified 3 lung tissue ROI and 1 boundary tissue ROI in 15 of the 16 subjects. When testing for changes from baseline in lung position, tidal volume, and respiratory system compliance, we found that PEEP displaced the ventilated lung region dorsally by 2 cm, decreased tidal volume by 1.3%, and increased the respiratory system compliance time constant by 0.3 s. F I O 2 decreased tidal volume by 0.7%. All effects were tested at p < 0.05 with n = 16. These findings suggest that the proposed ROI detection method is robust and sensitive to ventilation dynamics in the experimental setting

Relations between brain volumes, neuropsychological assessment and parental questionnaire in prematurely born children.

Science.gov (United States)

Lind, Annika; Haataja, Leena; Rautava, Liisi; Väliaho, Anniina; Lehtonen, Liisa; Lapinleimu, Helena; Parkkola, Riitta; Korkman, Marit

2010-05-01

The objective of this study is to assess the relationship between brain volumes at term equivalent age and neuropsychological functions at 5 years of age in very low birth weight (VLBW) children, and to compare the results from a neuropsychological assessment and a parental questionnaire at 5 years of age. The study group included a regional cohort of 97 VLBW children and a control group of 161 children born at term. At term equivalent age, brain magnetic resonance imaging (MRI) was performed on the VLBW children, and analysed for total and regional brain volumes. At 5 years of age, a psychologist assessed the neuropsychological performance with NEPSY II, and parents completed the Five to fifteen (FTF) questionnaire on development and behaviour. The results of the control group were used to give the age-specific reference values. No significant associations were found between the brain volumes and the NEPSY II domains. As for the FTF, significant associations were found between a smaller total brain tissue volume and poorer executive functions, between a smaller cerebellar volume and both poorer executive functions and motor skills, and, surprisingly, between a larger volume of brainstem and poorer language functions. Even after adjustment for total brain tissue volume, the two associations between the cerebellar volume and the FTF domains remained borderline significant (P = 0.05). The NEPSY II domains Executive Functioning, Language and Motor Skills were significantly associated with the corresponding FTF domains. In conclusion, altered brain volumes at term equivalent age appear to affect development still at 5 years of age. The FTF seems to be a good instrument when used in combination with other neuropsychological assessment.

Three-dimensional reconstruction of colorectal tumors from serial tissue sections by computer graphics: a preliminary study.

Science.gov (United States)

Kikuchi, S; Matsuzaki, H; Kondo, K; Ohtani, Y; Ihara, A; Hiki, Y; Kakita, A; Kuwao, S

2000-01-01

We present herein the three-dimensional reconstruction of colorectal tumors, with particular reference to growth pattern into each layer of the colorectal wall, and measurement of tumor volume and surface area. Conventional tissue section images of colorectal tumors were analyzed using a computer graphics analysis program. The two-dimensional extent of invasion by each tumor into each layer of intestinal wall were determined from the images of each section. Based on data from multiple sections, tumor and surrounding normal tissue layers were reconstructed three-dimensionally, and volume and surface area of the tumors were determined. Using this technique, three-dimensional morphology of tumor and tumor progression into colorectal wall could be determined. Volume and surface area of the colon tumor were 4871 mm3 and 1741 mm2, respectively. Volume and surface area of the rectal tumor were 1090 mm3 and 877 mm2, respectively. This technique may provide a new approach for pathological analysis of colorectal carcinoma.

Micromechanical modeling of rate-dependent behavior of Connective tissues.

Science.gov (United States)

Fallah, A; Ahmadian, M T; Firozbakhsh, K; Aghdam, M M

2017-03-07

In this paper, a constitutive and micromechanical model for prediction of rate-dependent behavior of connective tissues (CTs) is presented. Connective tissues are considered as nonlinear viscoelastic material. The rate-dependent behavior of CTs is incorporated into model using the well-known quasi-linear viscoelasticity (QLV) theory. A planar wavy representative volume element (RVE) is considered based on the tissue microstructure histological evidences. The presented model parameters are identified based on the available experiments in the literature. The presented constitutive model introduced to ABAQUS by means of UMAT subroutine. Results show that, monotonic uniaxial test predictions of the presented model at different strain rates for rat tail tendon (RTT) and human patellar tendon (HPT) are in good agreement with experimental data. Results of incremental stress-relaxation test are also presented to investigate both instantaneous and viscoelastic behavior of connective tissues. Copyright © 2017 Elsevier Ltd. All rights reserved.

The In Vitro Response of Tissue Stem Cells to Irradiation With Different Linear Energy Transfers

NARCIS (Netherlands)

Nagle, Peter W; Hosper, Nynke A; Ploeg, Emily M; van Goethem, Marc-Jan; Brandenburg, Sytze; Langendijk, Johannes A; Chiu, Roland K; Coppes, Robert P

2016-01-01

PURPOSE: A reduction in the dose, irradiated volume, and sensitivity of, in particular, normal tissue stem cells is needed to advance radiation therapy. This could be obtained with the use of particles for radiation therapy. However, the radiation response of normal tissue stem cells is still an

Callosal tissue loss parallels subtle decline in psychomotor speed. A longitudinal quantitative MRI study. The LADIS Study

DEFF Research Database (Denmark)

Jokinen, Hanna; Frederiksen, Kristian S; Garde, Ellen

2012-01-01

in a compound measure of cognitive speed and motor control, but not in those of executive functions, memory, or global cognitive function. Total CC area and midbody remained significant predictors of speed also after adjusting for baseline WML volume, WML progression, and global brain atrophy. However......, the relationship between anterior CC and speed performance was mediated by WML volume. In conclusion, the overall and regional rate of CC tissue loss parallels longitudinal slowing of psychomotor performance. The adverse effect of CC tissue loss on psychomotor function may be driven by altered interhemispheric...

Design of a Multi-Pinhole Collimator for I-123 DaTscan Imaging on Dual-Headed SPECT Systems in Combination with a Fan-Beam Collimator.

Science.gov (United States)

King, Michael A; Mukherjee, Joyeeta M; Könik, Arda; Zubal, I George; Dey, Joyoni; Licho, Robert

2016-02-01

For the 2011 FDA approved Parkinson's Disease (PD) SPECT imaging agent I-123 labeled DaTscan, the volume of interest (VOI) is the interior portion of the brain. However imaging of the occipital lobe is also required with PD for calculation of the striatal binding ratio (SBR), a parameter of significance in early diagnosis, differentiation of PD from other disorders with similar clinical presentations, and monitoring progression. Thus we propose the usage of a combination of a multi-pinhole (MPH) collimator on one head of the SPECT system and a fan-beam on the other. The MPH would be designed to provide high resolution and sensitivity for imaging of the interior portion of the brain. The fan-beam collimator would provide lower resolution but complete sampling of the brain addressing data sufficiency and allowing a volume-of-interest to be defined over the occipital lobe for calculation of SBR's. Herein we focus on the design of the MPH component of the combined system. Combined reconstruction will be addressed in a subsequent publication. An analysis of 46 clinical DaTscan studies was performed to provide information to define the VOI, and design of a MPH collimator to image this VOI. The system spatial resolution for the MPH was set to 4.7 mm, which is comparable to that of clinical PET systems, and significantly smaller than that of fan-beam collimators employed in SPECT. With this set, we compared system sensitivities for three aperture array designs, and selected the 3 × 3 array due to it being the highest of the three. The combined sensitivity of the apertures for it was similar to that of an ultra-high resolution fan-beam (LEUHRF) collimator, but smaller than that of a high-resolution fan-beam collimator (LEHRF). On the basis of these results we propose the further exploration of this design through simulations, and the development of combined MPH and fan-beam reconstruction.

Perforator based rectus free tissue transfer for head and neck reconstruction: New reconstructive advantages from an old friend.

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Kang, Stephen Y; Spector, Matthew E; Chepeha, Douglas B

2017-11-01

To demonstrate three reconstructive advantages of the perforator based rectus free tissue transfer: long pedicle, customizable adipose tissue, and volume reconstruction without muscle atrophy within a contained space. Thirty patients with defects of the head and neck were reconstructed with the perforator based rectus free tissue transfer. Transplant success was 93%. Mean pedicle length was 13.4cm. Eleven patients (37%) had vessel-poor necks and the long pedicle provided by this transplant avoided the need for vein grafts in these patients. Adipose tissue was molded in 17 patients (57%). Twenty-five patients (83%) had defects within a contained space, such as the orbit, where it was critical to have a transplant that avoided muscle atrophy. The perforator based rectus free tissue transfer provides a long pedicle, moldable fat for flap customization, and is useful in reconstruction of defects within a contained space where volume loss due to muscle atrophy is prevented. Copyright © 2017 Elsevier Ltd. All rights reserved.

Registration of 3D ultrasound computer tomography and MRI for evaluation of tissue correspondences

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Hopp, T.; Dapp, R.; Zapf, M.; Kretzek, E.; Gemmeke, H.; Ruiter, N. V.

2015-03-01

3D Ultrasound Computer Tomography (USCT) is a new imaging method for breast cancer diagnosis. In the current state of development it is essential to correlate USCT with a known imaging modality like MRI to evaluate how different tissue types are depicted. Due to different imaging conditions, e.g. with the breast subject to buoyancy in USCT, a direct correlation is demanding. We present a 3D image registration method to reduce positioning differences and allow direct side-by-side comparison of USCT and MRI volumes. It is based on a two-step approach including a buoyancy simulation with a biomechanical model and free form deformations using cubic B-Splines for a surface refinement. Simulation parameters are optimized patient-specifically in a simulated annealing scheme. The method was evaluated with in-vivo datasets resulting in an average registration error below 5mm. Correlating tissue structures can thereby be located in the same or nearby slices in both modalities and three-dimensional non-linear deformations due to the buoyancy are reduced. Image fusion of MRI volumes and USCT sound speed volumes was performed for intuitive display. By applying the registration to data of our first in-vivo study with the KIT 3D USCT, we could correlate several tissue structures in MRI and USCT images and learn how connective tissue, carcinomas and breast implants observed in the MRI are depicted in the USCT imaging modes.

Possible role of mechanical force in regulating regeneration of the vascularized fat flap inside a tissue engineering chamber.

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Ye, Yuan; Yuan, Yi; Lu, Feng; Gao, Jianhua

2015-12-01

In plastic and reconstructive surgery, adipose tissue is widely used as effective filler for tissue defects. Strategies for treating soft tissue deficiency, which include free adipose tissue grafts, use of hyaluronic acid, collagen injections, and implantation of synthetic materials, have several clinical limitations. With the aim of overcoming these limitations, researchers have recently utilized tissue engineering chambers to produce large volumes of engineered vascularized fat tissue. However, the process of growing fat tissue in a chamber is still relatively limited, and can result in unpredictable or dissatisfactory final tissue volumes. Therefore, detailed understanding of the process is both necessary and urgent. Many studies have shown that mechanical force can change the function of cells via mechanotransduction. Here, we hypothesized that, besides the inflammatory response, one of the key factors to control the regeneration of vascularized fat flap inside a tissue engineering chamber might be the balance of mechanical forces. To test our hypothesis, we intend to change the balance of forces by means of measures in order to make the equilibrium point in favor of the direction of regeneration. If those measures proved to be feasible, they could be applied in clinical practice to engineer vascularized adipose tissue of predictable size and shape, which would in turn help in the advancement of tissue engineering. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimized path planning for soft tissue resection via laser vaporization

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Ross, Weston; Cornwell, Neil; Tucker, Matthew; Mann, Brian; Codd, Patrick

2018-02-01

Robotic and robotic-assisted surgeries are becoming more prevalent with the promise of improving surgical outcomes through increased precision, reduced operating times, and minimally invasive procedures. The handheld laser scalpel in neurosurgery has been shown to provide a more gentle approach to tissue manipulation on or near critical structures over classical tooling, though difficulties of control have prevented large scale adoption of the tool. This paper presents a novel approach to generating a cutting path for the volumetric resection of tissue using a computer-guided laser scalpel. A soft tissue ablation simulator is developed and used in conjunction with an optimization routine to select parameters which maximize the total resection of target tissue while minimizing the damage to surrounding tissue. The simulator predicts the ablative properties of tissue from an interrogation cut for tuning and simulates the removal of a tumorous tissue embedded on the surface of healthy tissue using a laser scalpel. We demonstrate the ability to control depth and smoothness of cut using genetic algorithms to optimize the ablation parameters and cutting path. The laser power level, cutting rate and spacing between cuts are optimized over multiple surface cuts to achieve the desired resection volumes.

A Stereological Method for the Quantitative Evaluation of Cartilage Repair Tissue

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Nyengaard, Jens Randel; Lind, Martin; Spector, Myron

2015-01-01

Objective To implement stereological principles to develop an easy applicable algorithm for unbiased and quantitative evaluation of cartilage repair. Design Design-unbiased sampling was performed by systematically sectioning the defect perpendicular to the joint surface in parallel planes providing 7 to 10 hematoxylin–eosin stained histological sections. Counting windows were systematically selected and converted into image files (40-50 per defect). The quantification was performed by two-step point counting: (1) calculation of defect volume and (2) quantitative analysis of tissue composition. Step 2 was performed by assigning each point to one of the following categories based on validated and easy distinguishable morphological characteristics: (1) hyaline cartilage (rounded cells in lacunae in hyaline matrix), (2) fibrocartilage (rounded cells in lacunae in fibrous matrix), (3) fibrous tissue (elongated cells in fibrous tissue), (4) bone, (5) scaffold material, and (6) others. The ability to discriminate between the tissue types was determined using conventional or polarized light microscopy, and the interobserver variability was evaluated. Results We describe the application of the stereological method. In the example, we assessed the defect repair tissue volume to be 4.4 mm3 (CE = 0.01). The tissue fractions were subsequently evaluated. Polarized light illumination of the slides improved discrimination between hyaline cartilage and fibrocartilage and increased the interobserver agreement compared with conventional transmitted light. Conclusion We have applied a design-unbiased method for quantitative evaluation of cartilage repair, and we propose this algorithm as a natural supplement to existing descriptive semiquantitative scoring systems. We also propose that polarized light is effective for discrimination between hyaline cartilage and fibrocartilage. PMID:26069715

Gender differences in age-related decline in regional cerebral glucose metabolism

International Nuclear Information System (INIS)

Bang, Seong Ae; Cho, Sang Soo; Yoon, Eun Jin; Park, Hyun Soo; Lee, Eun Ju; Kim, Yu Kyeong; Kim, Sang Sun

2007-01-01

In this study, we investigated gender differences in age-related declines in regional cerebral glucose metabolism using FDG-PET in a large population sample with a broad age range. 230 healthy subjects (90 male; age: 34-80 y, 140 females; age: 33-82 y) participated. Correlation maps showing age related declines in glucose uptake were created separately for each gender in SPM2. Using population-based probabilistic volume of interests (VOIs), VOIs were defined for the regions showing significant decline with aging. Age related declines were separately assessed within each age range using analysis of covariate in SPSS 13.0. In the total population without gender effect, age-related negative correlation of glucose metabolism was found in the bilateral inferior frontal gyri, bilateral caudate, bilateral thalamus, left insula, left superior frontal gyrus, left uncus, right superior temporal gyrus, right medial frontal gyrus, right parahippocampal gyrus, right anterior cingulate gyrus (P < 0.001 corrected, extent threshold k = 100). 14 VOIs values of brain regions were calculated based on this negative correlation results. The rate of decline across all defined VOIs assessed in the age category of 'more than 70' referenced to the category of '30- 39years' were 7.85% in the entire sample; 7.62% in male and 8.09% in female. Detailed analyses of declines in each age range showed separable patterns of declines across gender. In males, greater decline was observed after the age 60 (20.45%) than the ages of 30 and 50(7.98%). Whereas in females, greater declines were found in age 60s (20.15%) compared to 50s, and in 40(14.84%) compared to 30s. Age-related decline in cerebral glucose metabolism was found in both genders. We further observed that males show a relatively constant pattern of decline across a life span; whereas, females show a pattern of steep changes aging to 60s and to 40s, which may be related to changes in sex hormone levels after menopause

Gender differences in age-related decline in regional cerebral glucose metabolism

Energy Technology Data Exchange (ETDEWEB)

Bang, Seong Ae; Cho, Sang Soo; Yoon, Eun Jin; Park, Hyun Soo; Lee, Eun Ju; Kim, Yu Kyeong; Kim, Sang Sun [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

2007-07-01

In this study, we investigated gender differences in age-related declines in regional cerebral glucose metabolism using FDG-PET in a large population sample with a broad age range. 230 healthy subjects (90 male; age: 34-80 y, 140 females; age: 33-82 y) participated. Correlation maps showing age related declines in glucose uptake were created separately for each gender in SPM2. Using population-based probabilistic volume of interests (VOIs), VOIs were defined for the regions showing significant decline with aging. Age related declines were separately assessed within each age range using analysis of covariate in SPSS 13.0. In the total population without gender effect, age-related negative correlation of glucose metabolism was found in the bilateral inferior frontal gyri, bilateral caudate, bilateral thalamus, left insula, left superior frontal gyrus, left uncus, right superior temporal gyrus, right medial frontal gyrus, right parahippocampal gyrus, right anterior cingulate gyrus (P < 0.001 corrected, extent threshold k = 100). 14 VOIs values of brain regions were calculated based on this negative correlation results. The rate of decline across all defined VOIs assessed in the age category of 'more than 70' referenced to the category of '30- 39years' were 7.85% in the entire sample; 7.62% in male and 8.09% in female. Detailed analyses of declines in each age range showed separable patterns of declines across gender. In males, greater decline was observed after the age 60 (20.45%) than the ages of 30 and 50(7.98%). Whereas in females, greater declines were found in age 60s (20.15%) compared to 50s, and in 40(14.84%) compared to 30s. Age-related decline in cerebral glucose metabolism was found in both genders. We further observed that males show a relatively constant pattern of decline across a life span; whereas, females show a pattern of steep changes aging to 60s and to 40s, which may be related to changes in sex hormone levels after menopause.

Normal tissue complication probabilities correlated with late effects in the rectum after prostate conformal radiotherapy

International Nuclear Information System (INIS)

Dale, Einar; Olsen, Dag R.; Fossa, Sophie D.

1999-01-01

Purpose: Radiation therapy of deep-sited tumours will always result in normal tissue doses to some extent. The aim of this study was to calculate different risk estimates of late effects in the rectum for a group of cancer prostate patients treated with conformal radiation therapy (CRT) and correlate these estimates with the occurrences of late effects. Since the rectum is a hollow organ, several ways of generating dose-volume distributions over the organ are possible, and we wanted to investigate two of them. Methods and Materials: A mathematical model, known as the Lyman-Kutcher model, conventionally used to estimate normal tissue complication probabilities (NTCP) associated with radiation therapy, was applied to a material of 52 cancer prostate patients. The patients were treated with a four field box technique, with the rectum as organ at risk. Dose-volume histograms (DVH) were generated for the whole rectum (including the cavity) and of the rectum wall. One to two years after the treatment, the patients completed a questionnaire concerning bowel (rectum) related morbidity quantifying the extent of late effects. Results: A correlation analysis using Spearman's rank correlation coefficient, for NTCP values calculated from the DVHs and the patients' scores, gave correlation coefficients which were not statistically significant at the p max , of the whole rectum, correlated better to observed late toxicity than D max derived from histograms of the rectum wall. Correlation coefficients from 'high-dose' measures were larger than those calculated from the NTCP values. Accordingly, as the volume parameter of the Lyman-Kutcher model was reduced, raising the impact of small high-dose volumes on the NTCP values, the correlation between observed effects and NTCP values became significant at p < 0.01 level. Conclusions: 1) High-dose levels corresponding to small volume fractions of the cumulative dose-volume histograms were best correlated with the occurrences of late

Synchrotron microCT imaging of soft tissue in juvenile zebrafish reveals retinotectal projections

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Xin, Xuying; Clark, Darin; Ang, Khai Chung; van Rossum, Damian B.; Copper, Jean; Xiao, Xianghui; La Riviere, Patrick J.; Cheng, Keith C.

2017-02-01

Biomedical research and clinical diagnosis would benefit greatly from full volume determinations of anatomical phenotype. Comprehensive tools for morphological phenotyping are central for the emerging field of phenomics, which requires high-throughput, systematic, accurate, and reproducible data collection from organisms affected by genetic, disease, or environmental variables. Theoretically, complete anatomical phenotyping requires the assessment of every cell type in the whole organism, but this ideal is presently untenable due to the lack of an unbiased 3D imaging method that allows histopathological assessment of any cell type despite optical opacity. Histopathology, the current clinical standard for diagnostic phenotyping, involves the microscopic study of tissue sections to assess qualitative aspects of tissue architecture, disease mechanisms, and physiological state. However, quantitative features of tissue architecture such as cellular composition and cell counting in tissue volumes can only be approximated due to characteristics of tissue sectioning, including incomplete sampling and the constraints of 2D imaging of 5 micron thick tissue slabs. We have used a small, vertebrate organism, the zebrafish, to test the potential of microCT for systematic macroscopic and microscopic morphological phenotyping. While cell resolution is routinely achieved using methods such as light sheet fluorescence microscopy and optical tomography, these methods do not provide the pancellular perspective characteristic of histology, and are constrained by the limited penetration of visible light through pigmented and opaque specimens, as characterizes zebrafish juveniles. Here, we provide an example of neuroanatomy that can be studied by microCT of stained soft tissue at 1.43 micron isotropic voxel resolution. We conclude that synchrotron microCT is a form of 3D imaging that may potentially be adopted towards more reproducible, large-scale, morphological phenotyping of optically

Study on delineation of tumor volume of primary locally advanced nasopharyngeal carcinoma after induction chemotherapy

International Nuclear Information System (INIS)

Long Jinhua; Dong Shi; Jin Feng; Wu Weili; Gan Jiaying; Chen Haixia; Li Yuanyuan; Gong Xiuyun