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MR image segmentation

Jae W Song, Gerlinde M Gruber, Janina M Patsch, Rainer Seidl, Daniela Prayer, Gregor Kasprian
Prenatal detection of abnormal white matter tracts might serve as a structural marker for altered neurodevelopment. As a result of many technical and patient-related challenges, the accuracy of prenatal tractography remains unknown. We hypothesized that characteristics of prenatal tractography of the corpus callosum and corticospinal tracts derived from fetal diffusion tensor imaging (DTI) data are accurate and predictive of the integrity of these tracts postnatally. We compared callosal and corticospinal tracts of 12 subjects with paired prenatal (age: 23-35 gestational weeks) and postnatal (age: 1 day to 2 years) DTI examinations (b values of 0 s/mm2 and 700 s/mm2 , 16 gradient encoding directions) using deterministic tractography...
April 2018: Pediatric Radiology
D K Boruah, A Prakash, B B Gogoi, R R Yadav, D D Dhingani, B Sarma
BACKGROUND AND PURPOSE: Hirayama disease is a benign focal amyotrophy of the distal upper limbs involving C7, C8, and T1 segmental myotomes with sparing of the brachioradialis and proximal muscles of the upper limb innervated by C5-6 myotomes. The objective of the present study was to study the utility of MR imaging in young patients presenting with weakness and wasting of the distal upper extremity and to evaluate the importance of the laminodural space during flexion cervical MR imaging...
March 15, 2018: AJNR. American Journal of Neuroradiology
Shotaro Kanao, Masako Kataoka, Mami Iima, Debra Masako Ikeda, Masakazu Toi, Kaori Togashi
OBJECTIVES: Benign and malignant inflammatory breast lesions demonstrate similar findings on both T2 weighted imaging (T2WI) and dynamic contrast enhanced (DCE) images. We hypothesized that benign inflammatory lesions might be differentiated form malignancies using a combination of apparent diffusion coefficient (ADC) values derived from diffusion weighted images (DWI) and T2WI. MATERIALS AND METHODS: We retrospectively reviewed 162 patients undergoing breast MRI (T2WI, DWI and DCE images) between 2008 and 2015 who had breast lesions with high T2WI signal intensity (High T2 SI) including 14 benign inflammatory lesions, 69 benign non-inflammatory lesions, 16 malignant inflammatory lesions and 63 malignant non-inflammatory lesions...
March 12, 2018: Magnetic Resonance Imaging
Keisuke Usui, Keisuke Sasai, Koichi Ogawa
This study aimed to verify the validity of generating treatment plans for volumetric arc therapy (VMAT) for prostate cancer using magnetic resonance (MR) imaging with a dose calculation algorithm in Acuros XB (Eclipse version 13.6; Varian Medical Systems, Palo Alto, CA, USA) based on deterministically solving the linear Boltzmann transport equations. Four different classes were applied to prostate MR images: MRW (all water equivalent); MRW+B (water and bone); MRS+B (soft tissue and bone); and MRS+B+G (soft tissue, bone, and rectal gas)...
March 14, 2018: Radiological Physics and Technology
Tsang Chun On Anderson, Yeung Wan Lung Ryo, Mak Ka Fung, Lui Wai Man
We report a case of unique location of an aneurysm at the atlanto-axial extradural segment of a unilateral aberrant vertebral artery. The MRI vessel wall imaging findings and possible mechanism of aneurysm formation were discussed. A 5 mm extracranial vertebral artery aneurysm located at the interlaminar space between C1 and C2 was diagnosed in a woman presenting with occipital headache. The index vertebral artery ran an aberrant course at the V3 segment, where it entered the dura between C1 and C2 instead of the usual atlanto-occipital space...
March 2018: Neurointervention
Evangelia Tsolaki, Angela Downes, William Speier, W Jeff Elias, Nader Pouratian
Magnetic Resonance-guided Focused UltraSound (MRgFUS) offers an incisionless approach to treat essential tremor (ET). Due to lack of evident internal anatomy on traditional structural imaging, indirect targeting must still be used to localize the lesion. Here, we investigate the potential predictive value of probabilistic tractography guided thalamic targeting by defining how tractography-defined targets, lesion size and location, and clinical outcomes interrelate. MR imaging and clinical outcomes from 12 ET patients that underwent MRgFUS thalamotomy in a pilot study at the University of Virginia were evaluated in this analysis...
2018: NeuroImage: Clinical
Pinar Yilmaz, Karel Wallecan, Wisnumurti Kristanto, Jean-Paul Aben, Adriaan Moelker
The purpose of this study was to evaluate a semi-automatic right ventricle segmentation method on short-axis cardiac cine MR images which segment all right ventricle contours in a cardiac phase using one seed contour. Twenty-eight consecutive short-axis, four-chamber, and tricuspid valve view cardiac cine MRI examinations of healthy volunteers were used. Two independent observers performed the manual and automatic segmentations of the right ventricles. Analyses were based on the ventricular volume and ejection fraction of the right heart chamber...
March 9, 2018: Journal of Digital Imaging: the Official Journal of the Society for Computer Applications in Radiology
Vincenzo Positano, Antonella Meloni, Francesca Macaione, Maria Filomena Santarelli, Laura Pistoia, Andrea Barison, Salvatore Novo, Alessia Pepe
To compare image analysis methods for the assessment of left ventricle non-compaction from cardiac magnetic resonance (CMR) imaging. CMR images were analyzed in 20 patients and 10 normal subjects. A reference model of the MR signal was introduced and validated based on image data. Non-compact (NC) myocardium size and distribution were assessed by tracing a single, continuous contour delimiting trabeculated region (Jacquier) or by one-by-one selection of trabeculae (Grothoff). The global non-compact/compact (NC/C) ratio, the NC mass, and the segmental NC/C ratio were assessed...
March 9, 2018: International Journal of Cardiovascular Imaging
Chunfeng Lian, Jun Zhang, Mingxia Liu, Xiaopeng Zong, Sheng-Che Hung, Weili Lin, Dinggang Shen
Accurate segmentation of perivascular spaces (PVSs) is an important step for quantitative study of PVS morphology. However, since PVSs are the thin tubular structures with relatively low contrast and also the number of PVSs is often large, it is challenging and time-consuming for manual delineation of PVSs. Although several automatic/semi-automatic methods, especially the traditional learning-based approaches, have been proposed for segmentation of 3D PVSs, their performance often depends on the hand-crafted image features, as well as sophisticated preprocessing operations prior to segmentation (e...
February 27, 2018: Medical Image Analysis
Jesper D Nielsen, Kristoffer H Madsen, Oula Puonti, Hartwig R Siebner, Christian Bauer, Camilla Gøbel Madsen, Guilherme B Saturnino, Axel Thielscher
Anatomically realistic volume conductor models of the human head are important for accurate forward modeling of the electric field during transcranial brain stimulation (TBS), electro- (EEG) and magnetoencephalography (MEG). In particular, the skull compartment exerts a strong influence on the field distribution due to its low conductivity, suggesting the need to represent its geometry accurately. However, automatic skull reconstruction from structural magnetic resonance (MR) images is difficult, as compact bone has a very low signal in magnetic resonance imaging (MRI)...
March 5, 2018: NeuroImage
Natally Horvat, Harini Veeraraghavan, Monika Khan, Ivana Blazic, Junting Zheng, Marinela Capanu, Evis Sala, Julio Garcia-Aguilar, Marc J Gollub, Iva Petkovska
Purpose To investigate the value of T2-weighted-based radiomics compared with qualitative assessment at T2-weighted imaging and diffusion-weighted (DW) imaging for diagnosis of clinical complete response in patients with rectal cancer after neoadjuvant chemotherapy-radiation therapy (CRT). Materials and Methods This retrospective study included 114 patients with rectal cancer who underwent magnetic resonance (MR) imaging after CRT between March 2012 and February 2016. Median age among women (47 of 114, 41%) was 55...
March 7, 2018: Radiology
Georg Hille, Sylvia Saalfeld, Steffen Serowy, Klaus Tönnies
BACKGROUND AND OBJECTIVE: In this work we propose a 3D vertebral body segmentation approach for clinical magnetic resonance (MR) spine imaging. So far, vertebrae segmentation approaches in MR spine imaging are either limited to particular MR imaging sequences or require minutes to compute, which can be hindering in clinical routine. The major contribution of our work is a reasonably precise segmentation result, within seconds and with minimal user interaction, for spine MR imaging commonly used in clinical routine...
March 2018: Computer Methods and Programs in Biomedicine
Raluca Pascalau, Roxana Popa Stănilă, Silviu Sfrângeu, Bianca Szabo
BACKGROUND: The limbic tracts are involved in crucial cerebral functions such as memory, emotion and behavior. The complex architecture of the limbic circuit makes it harder to approach compared to other white matter networks. Our study aims to describe the three-dimensional anatomy of the limbic white matter by use of two complementary study methods, namely ex vivo fiber dissection and in vivo MRI based tractography. METHODS: Three fiber dissection protocols were performed using blunt wooden instruments and a surgical microscope on formalin fixed brains prepared according to the Klingler method...
February 28, 2018: World Neurosurgery
Merry Mani, Vincent Magnotta, Mathews Jacob
PURPOSE: To reconstruct artifact-free images from measured k-space data, when the actual k-space trajectory deviates from the nominal trajectory due to gradient imperfections. METHODS: Trajectory errors arising from eddy currents and gradient delays introduce phase inconsistencies in several fast scanning MR pulse sequences, resulting in image artifacts. The proposed algorithm provides a novel framework to compensate for this phase distortion. The algorithm relies on the construction of a multi-block Hankel matrix, where each block is constructed from k-space segments with the same phase distortion...
February 28, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Farnaz Hoseini, Asadollah Shahbahrami, Peyman Bayat
Image segmentation is one of the most common steps in digital image processing, classifying a digital image into different segments. The main goal of this paper is to segment brain tumors in magnetic resonance images (MRI) using deep learning. Tumors having different shapes, sizes, brightness and textures can appear anywhere in the brain. These complexities are the reasons to choose a high-capacity Deep Convolutional Neural Network (DCNN) containing more than one layer. The proposed DCNN contains two parts: architecture and learning algorithms...
February 27, 2018: Journal of Digital Imaging: the Official Journal of the Society for Computer Applications in Radiology
P Kanmani, P Marikkannu
Medical image processing is the most challenging and emerging field nowadays. Magnetic Resonance Images (MRI) act as the source for the development of classification system. The extraction, identification and segmentation of infected region from Magnetic Resonance (MR) brain image is significant concern but a dreary and time-consuming task performed by radiologists or clinical experts, and the final classification accuracy depends on their experience only. To overcome these limitations, it is necessary to use computer-aided techniques...
February 26, 2018: Journal of Medical Systems
Lian Shanshan, Shi Feng, Wei Kaikai, Zhang Yijun, Liu Huiming, Xie Chuanmiao
RATIONALE AND OBJECTIVES: This study aims to investigate the value of intravoxel incoherent motion (IVIM)-derived parameters for early evaluation of the efficiency of radiofrequency ablation (RFA) treatment for rabbit liver VX2 tumor. MATERIALS AND METHODS: Eighteen rabbit liver VX2 tumor models were constructed, and computed tomography-guided RFA was performed. One day before and 7 days after RFA, 18 models underwent magnetic resonance imaging, including contrast-enhanced imaging and IVIM diffusion-weighted imaging with 16 b-factors (0-1000 s/mm2 )...
February 22, 2018: Academic Radiology
Sofia Kvernby, Mattias Rönnerfalk, Marcel Warntjes, Carl-Johan Carlhäll, Eva Nylander, Jan Engvall, Éva Tamás, Tino Ebbers
BACKGROUND: Diffuse myocardial fibrosis is associated with adverse outcomes, although detection and quantification is challenging. Cardiac MR relaxation times mapping represents a promising imaging biomarker for diffuse myocardial fibrosis. PURPOSE: To investigate whether relaxation times can detect longitudinal changes in myocardial tissue composition associated with diffuse fibrosis in patients with severe aortic stenosis (AS) before and after aortic valve replacement (AVR)...
February 23, 2018: Journal of Magnetic Resonance Imaging: JMRI
R Kleinloog, J J M Zwanenburg, B Schermers, E Krikken, Y M Ruigrok, P R Luijten, F Visser, L Regli, G J E Rinkel, B H Verweij
BACKGROUND AND PURPOSE: Aneurysm volume pulsation is a potential predictor of intracranial aneurysm rupture. We evaluated whether 7T MR imaging can quantify aneurysm volume pulsation. MATERIALS AND METHODS: In Stage I of the study, 10 unruptured aneurysms in 9 patients were studied using a high-resolution (0.6-mm, isotropic) 3D gradient-echo sequence with cardiac gating. Semiautomatic segmentation was used to measure aneurysm volume (in cubic millimeters) per cardiac phase...
February 22, 2018: AJNR. American Journal of Neuroradiology
Dr Scott Fernquest, Dr Daniel Park, Dr Marija Marcan, Mr Antony Palmer, Dr Irina Voiculescu, Prof Sion Glyn-Jones
Manual segmentation is a significant obstacle in the analysis of compositional MRI for clinical decision-making and research. Our aim was to produce a fast, accurate, reproducible, and clinically viable semi-automated method for segmentation of hip MRI. We produced a semi-automated segmentation method for cartilage segmentation of hip MRI sequences consisting of a two step process: (1) fully automated hierarchical partitioning of the data volume generated using a bespoke segmentation approach applied recursively, followed by (2) user selection of the regions of interest using a region editor...
February 22, 2018: Journal of Orthopaedic Research: Official Publication of the Orthopaedic Research Society
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