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MR image segmentation

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https://www.readbyqxmd.com/read/27914956/individual-refinement-of-attenuation-correction-maps-for-hybrid-pet-mr-based-on-multi-resolution-regional-learning
#1
Kuangyu Shi, Sebastian Fürst, Liang Sun, Mathias Lukas, Nassir Navab, Stefan Förster, Sibylle I Ziegler
PET/MR is an emerging hybrid imaging modality. However, attenuation correction (AC) remains challenging for hybrid PET/MR in generating accurate PET images. Segmentation-based methods on special MR sequences are most widely recommended by vendors. However, their accuracy is usually not high. Individual refinement of available certified attenuation maps may be helpful for further clinical applications. In this study, we proposed a multi-resolution regional learning (MRRL) scheme to utilize the internal consistency of the patient data...
November 19, 2016: Computerized Medical Imaging and Graphics: the Official Journal of the Computerized Medical Imaging Society
https://www.readbyqxmd.com/read/27913428/migration-pathways-of-thalamic-neurons-and-development-of-thalamocortical-connections-in-humans-revealed-by-diffusion-mr-tractography
#2
Molly Wilkinson, Tara Kane, Rongpin Wang, Emi Takahashi
The thalamus plays an important role in signal relays in the brain, with thalamocortical (TC) neuronal pathways linked to various sensory/cognitive functions. In this study, we aimed to see fetal and postnatal development of the thalamus including neuronal migration to the thalamus and the emergence/maturation of the TC pathways. Pathways from/to the thalami of human postmortem fetuses and in vivo subjects ranging from newborns to adults with no neurological histories were studied using high angular resolution diffusion MR imaging (HARDI) tractography...
December 2, 2016: Cerebral Cortex
https://www.readbyqxmd.com/read/27908279/co-existing-intracranial-and-extracranial-carotid-artery-atherosclerotic-plaques-and-recurrent-stroke-risk-a-three-dimensional-multicontrast-cardiovascular-magnetic-resonance-study
#3
Yilan Xu, Chun Yuan, Zechen Zhou, Le He, Donghua Mi, Rui Li, Yuanyuan Cui, Yilong Wang, Yongjun Wang, Gaifen Liu, Zhuozhao Zheng, Xihai Zhao
BACKGROUND: As a systemic disease, atherosclerosis commonly affects intracranial and extracranial carotid arteries simultaneously which is defined as co-existing plaques. Previous studies demonstrated that co-existing atherosclerotic diseases are significantly associated with ischemic cerebrovascular events. The aim of this study was to investigate the characteristics of co-existing intracranial and extracranial carotid atherosclerotic plaques and their relationships with recurrent stroke by using 3D multi-contrast magnetic resonance (MR) vessel wall imaging...
December 2, 2016: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/27908177/automatic-segmentation-of-right-ventricle-in-cardiac-cine-mr-images-using-a-saliency-analysis
#4
Angélica Atehortúa, Maria A Zuluaga, Juan D García, Eduardo Romero
PURPOSE: Accurate measurement of the right ventricle (RV) volume is important for the assessment of the ventricular function and a biomarker of the progression of any cardiovascular disease. However, the high RV variability makes difficult a proper delineation of the myocardium wall. This paper introduces a new automatic method for segmenting the RV volume from short axis cardiac magnetic resonance (MR) images by a salient analysis of temporal and spatial observations. METHODS: The RV volume estimation starts by localizing the heart as the region with the most coherent motion during the cardiac cycle...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27908163/learning-based-3t-brain-mri-segmentation-with-guidance-from-7t-mri-labeling
#5
Minghui Deng, Renping Yu, Li Wang, Feng Shi, Pew-Thian Yap, Dinggang Shen
PURPOSE: Segmentation of brain magnetic resonance (MR) images into white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) is crucial for brain structural measurement and disease diagnosis. Learning-based segmentation methods depend largely on the availability of good training ground truth. However, the commonly used 3T MR images are of insufficient image quality and often exhibit poor intensity contrast between WM, GM, and CSF. Therefore, they are not ideal for providing good ground truth label data for training learning-based methods...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27893375/liver-segmentation-on-ct-and-mr-using-laplacian-mesh-optimization
#6
Gabriel Chartrand, Thierry Cresson, Ramnada Chav, Akshat Gotra, An Tang, Jacques A de Guise
OBJECTIVE: The purpose of this paper is to describe a semi-automated segmentation method for the liver and evaluate its performance on CT-scan and MR images. METHODS: First, an approximate 3D model of the liver is initialized from a few usergenerated contours to globally outline the liver shape. The model is then automatically deformed by a Laplacian mesh optimization scheme until it precisely delineates the patient's liver. A correction tool was implemented to allow the user to improve the segmentation until satisfaction...
November 21, 2016: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/27891069/automatic-segmentation-of-human-cortical-layer-complexes-and-architectural-areas-using-ex-vivo-diffusion-mri-and-its-validation
#7
Matteo Bastiani, Ana-Maria Oros-Peusquens, Arne Seehaus, Daniel Brenner, Klaus Möllenhoff, Avdo Celik, Jörg Felder, Hansjürgen Bratzke, Nadim J Shah, Ralf Galuske, Rainer Goebel, Alard Roebroeck
Recently, several magnetic resonance imaging contrast mechanisms have been shown to distinguish cortical substructure corresponding to selected cortical layers. Here, we investigate cortical layer and area differentiation by automatized unsupervised clustering of high-resolution diffusion MRI data. Several groups of adjacent layers could be distinguished in human primary motor and premotor cortex. We then used the signature of diffusion MRI signals along cortical depth as a criterion to detect area boundaries and find borders at which the signature changes abruptly...
2016: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/27884115/chemical-shift-mr-imaging-in-the-lumbar-vertebra-the-effect-of-field-strength-scanner-vendors-and-flip-angles-in-repeatability-of-signal-intensity-index-measurement
#8
Zebin Xiao, Jian Li, Chengqi Li, Yuyang Zhang, Dejun She, Dairong Cao
BACKGROUND: To evaluate the reproducibility of signal intensity index (SII) measurements with MRI systems from different vendors and with different field strengths, and to test the effectiveness of flip angle. METHODS: Thirty-two healthy volunteers (mean age 35.3 ± 9.3 years) were enrolled in this ethics committee-approved study. Chemical shift MR imaging was performed on 1.5- and 3.0-T MR systems from three vendors. Two independent observers measured SII values in five lumbar segments...
November 25, 2016: BMC Medical Imaging
https://www.readbyqxmd.com/read/27878463/tracking-of-the-inferior-alveolar-nerve-its-implication-in-surgical-planning
#9
Jimoh O Agbaje, Elke Van de Casteele, Ahmed S Salem, Dickson Anumendem, Ivo Lambrichts, Constantinus Politis
OBJECTIVES: The objective of the study is to assess the correlation between the mandibular canal tracing done on cone beam CT (CBCT) data, with the size, shape, and position of the neurovascular bundle (NB) obtained by magnetic resonance imaging (MRI). MATERIAL AND METHODS: Six human cadaver mandibles were scanned with a CBCT Promax® scanner (Planmeca, Helsinki, Finland) and with an Ingenia® 3.0 T MR system (Philips, Amsterdam, The Netherlands). The NB was segmented from the MRI dataset, while the mandibular canal (MC) tracing was done on the CBCT images...
November 22, 2016: Clinical Oral Investigations
https://www.readbyqxmd.com/read/27876066/in-vivo-cardiovascular-magnetic-resonance-of-2d-vessel-wall-diffusion-anisotropy-in-carotid-arteries
#10
Peter Opriessnig, Harald Mangge, Rudolf Stollberger, Hannes Deutschmann, Gernot Reishofer
BACKGROUND: Diffusion weighted (DW) cardiovascular magnetic resonance (CMR) has shown great potential to discriminate between healthy and diseased vessel tissue by evaluating the apparent diffusion coefficient (ADC) along the arterial axis. Recently, ex vivo studies on porcine arteries utilizing diffusion tensor imaging (DTI) revealed a circumferential fiber orientation rather than an organization in axial direction, suggesting dominant diffusion perpendicular to the slice direction. In the present study, we propose a method to access tangential and radial diffusion of carotids in vivo by utilizing a pulse sequence that enables high resolution DW imaging in combination with a two-dimensional (2D) diffusion gradient direction sampling scheme perpendicular to the longitudinal axis of the artery...
November 23, 2016: Journal of Cardiovascular Magnetic Resonance
https://www.readbyqxmd.com/read/27873147/fully-automated-mr-liver-volumetry-using-watershed-segmentation-coupled-with-active-contouring
#11
Hieu Trung Huynh, Ngoc Le-Trong, Pham The Bao, Aytek Oto, Kenji Suzuki
PURPOSE: Our purpose is to develop a fully automated scheme for liver volume measurement in abdominal MR images, without requiring any user input or interaction. METHODS: The proposed scheme is fully automatic for liver volumetry from 3D abdominal MR images, and it consists of three main stages: preprocessing, rough liver shape generation, and liver extraction. The preprocessing stage reduced noise and enhanced the liver boundaries in 3D abdominal MR images. The rough liver shape was revealed fully automatically by using the watershed segmentation, thresholding transform, morphological operations, and statistical properties of the liver...
November 21, 2016: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/27871865/iterative-reconstruction-of-radially-sampled-31-p-bssfp-data-using-prior-information-from-1-h-mri
#12
Kristian Rink, Nadia Benkhedah, Moritz C Berger, Christine Gnahm, Nicolas G R Behl, Jonathan M Lommen, Vanessa Stahl, Peter Bachert, Mark E Ladd, Armin M Nagel
The purpose of this study is to improve direct phosphorus ((31)P) MR imaging. Therefore, 3D density-adapted radially-sampled balanced steady-state free precession (bSSFP) sequences were developed and an iterative approach exploiting additional anatomical information from hydrogen ((1)H) data was evaluated. Three healthy volunteers were examined at B0=7T in order to obtain the spatial distribution of the phosphocreatine (PCr) intensities in the human calf muscle with a nominal isotropic resolution of 10mm in an acquisition time of 10min...
November 18, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27871000/comparison-of-atlas-based-techniques-for-whole-body-bone-segmentation
#13
Hossein Arabi, Habib Zaidi
We evaluate the accuracy of whole-body bone extraction from whole-body MR images using a number of atlas-based segmentation methods. The motivation behind this work is to find the most promising approach for the purpose of MRI-guided derivation of PET attenuation maps in whole-body PET/MRI. To this end, a variety of atlas-based segmentation strategies commonly used in medical image segmentation and pseudo-CT generation were implemented and evaluated in terms of whole-body bone segmentation accuracy. Bone segmentation was performed on 23 whole-body CT/MR image pairs via leave-one-out cross validation procedure...
November 12, 2016: Medical Image Analysis
https://www.readbyqxmd.com/read/27868105/feasibility-of-automated-3-dimensional-magnetic-resonance-imaging-pancreas-segmentation
#14
Shuiping Gou, Percy Lee, Peng Hu, Jean-Claude Rwigema, Ke Sheng
PURPOSE: With the advent of MR guided radiotherapy, internal organ motion can be imaged simultaneously during treatment. In this study, we evaluate the feasibility of pancreas MRI segmentation using state-of-the-art segmentation methods. METHODS AND MATERIAL: T2 weighted HASTE and T1 weighted VIBE images were acquired on 3 patients and 2 healthy volunteers for a total of 12 imaging volumes. A novel dictionary learning (DL) method was used to segment the pancreas and compared to t mean-shift merging (MSM), distance regularized level set (DRLS), graph cuts (GC) and the segmentation results were compared to manual contours using Dice's index (DI), Hausdorff distance and shift of the-center-of-the-organ (SHIFT)...
July 2016: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/27864579/automated-segmentation-reveals-silent-radiographic-progression-in-adult-onset-vanishing-white-matter-disease
#15
Thomas Huber, Marina Herwerth, Esther Alberts, Jan S Kirschke, Claus Zimmer, Ruediger Ilg
Adult-onset vanishing white-matter disease (VWM) is a rare autosomal recessive disease with neurological symptoms such as ataxia and paraparesis, showing extensive white-matter hyperintensities (WMH) on magnetic resonance (MR) imaging. Besides symptom-specific scores like the International Cooperative Ataxia Rating Scale (ICARS), there is no established tool to monitor disease progression. Because of extensive WMH, visual comparison of MR images is challenging. Here, we report the results of an automated method of segmentation to detect alterations in T2-weighted fluid-attenuated-inversion-recovery (FLAIR) sequences in a one-year follow-up study of a clinically stable patient with genetically diagnosed VWM...
November 18, 2016: Neuroradiology Journal
https://www.readbyqxmd.com/read/27864083/robust-skull-stripping-using-multiple-mr-image-contrasts-insensitive-to-pathology
#16
Snehashis Roy, John A Butman, Dzung L Pham
Automatic skull-stripping or brain extraction of magnetic resonance (MR) images is often a fundamental step in many neuroimage processing pipelines. The accuracy of subsequent image processing relies on the accuracy of the skull-stripping. Although many automated stripping methods have been proposed in the past, it is still an active area of research particularly in the context of brain pathology. Most stripping methods are validated on T1-w MR images of normal brains, especially because high resolution T1-w sequences are widely acquired and ground truth manual brain mask segmentations are publicly available for normal brains...
November 15, 2016: NeuroImage
https://www.readbyqxmd.com/read/27862111/quantification-of-total-fetal-brain-volume-using-3d-mr-imaging-data-acquired-in-utero
#17
Deborah Jarvis, Rahim Akram, Laura Mandefield, Michael Paddock, Paul Armitage, Paul D Griffiths
OBJECTIVE: Interpretation of MR imaging of the fetal brain in utero is primarily undertaken using 2D images to provide anatomical information about structural abnormalities. It is now possible to obtain 3D image acquisitions that allow measurement of fetal brain volumes that are potentially useful clinically. The aim of our current work is to provide reference values of total brain volumes obtained from a cohort of low risk fetuses with no abnormalities on ante-natal ultrasonography and in utero MR imaging...
November 13, 2016: Prenatal Diagnosis
https://www.readbyqxmd.com/read/27855691/semiautomatic-segmentation-of-the-kidney-in-magnetic-resonance-images-using-unimodal-thresholding
#18
Martin Sandmair, Matthias Hammon, Hannes Seuss, Ragnar Theis, Michael Uder, Rolf Janka
BACKGROUND: Total kidney volume (TKV) is an important marker for the presence or progression of chronic kidney disease, however, routine ultrasonography underestimates renal volume to a high and varying degree. OBJECTIVE: The aim of this work was to adapt and evaluate a semi-automatic unimodal thresholding method for volumetric analysis of the kidney in native T2-weighted magnetic resonance (MR) images. METHODS: In a group of healthy volunteers (n = 24; 48 kidneys), we defined a region of interest (ROI) by manually tracing the outline of the kidney in every MR image...
November 17, 2016: BMC Research Notes
https://www.readbyqxmd.com/read/27853751/quantitative-mri-radiomics-in-the-prediction-of-molecular-classifications-of-breast-cancer-subtypes-in-the-tcga-tcia-data-set
#19
Hui Li, Yitan Zhu, Elizabeth S Burnside, Erich Huang, Karen Drukker, Katherine A Hoadley, Cheng Fan, Suzanne D Conzen, Margarita Zuley, Jose M Net, Elizabeth Sutton, Gary J Whitman, Elizabeth Morris, Charles M Perou, Yuan Ji, Maryellen L Giger
Using quantitative radiomics, we demonstrate that computer-extracted magnetic resonance (MR) image-based tumor phenotypes can be predictive of the molecular classification of invasive breast cancers. Radiomics analysis was performed on 91 MRIs of biopsy-proven invasive breast cancers from National Cancer Institute's multi-institutional TCGA/TCIA. Immunohistochemistry molecular classification was performed including estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, and for 84 cases, the molecular subtype (normal-like, luminal A, luminal B, HER2-enriched, and basal-like)...
2016: NPJ Breast Cancer
https://www.readbyqxmd.com/read/27851871/robust-sliding-window-reconstruction-for-accelerating-the-acquisition-of-mr-fingerprinting
#20
Xiaozhi Cao, Congyu Liao, Zhixing Wang, Ying Chen, Huihui Ye, Hongjian He, Jianhui Zhong
PURPOSE: To develop a method for accelerated and robust MR fingerprinting (MRF) with improved image reconstruction and parameter matching processes. THEORY AND METHODS: A sliding-window (SW) strategy was applied to MRF, in which signal and dictionary matching was conducted between fingerprints consisting of mixed-contrast image series reconstructed from consecutive data frames segmented by a sliding window, and a precalculated mixed-contrast dictionary. The effectiveness and performance of this new method, dubbed SW-MRF, was evaluated in both phantom and in vivo...
November 7, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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