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https://www.readbyqxmd.com/read/27917527/simultaneous-orthogonal-plane-imaging
#1
Nikolai J Mickevicius, Eric S Paulson
PURPOSE: Intrafraction motion can result in a smearing of planned external beam radiation therapy dose distributions, resulting in an uncertainty in dose actually deposited in tissue. The purpose of this paper is to present a pulse sequence that is capable of imaging a moving target at a high frame rate in two orthogonal planes simultaneously for MR-guided radiotherapy. THEORY: By balancing the zero gradient moment on all axes, slices in two orthogonal planes may be spatially encoded simultaneously...
December 4, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/27914956/individual-refinement-of-attenuation-correction-maps-for-hybrid-pet-mr-based-on-multi-resolution-regional-learning
#2
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/27913362/learning-to-predict-eye-fixations-via-multiresolution-convolutional-neural-networks
#3
Nian Liu, Junwei Han, Tianming Liu, Xuelong Li
Eye movements in the case of freely viewing natural scenes are believed to be guided by local contrast, global contrast, and top-down visual factors. Although a lot of previous works have explored these three saliency cues for several years, there still exists much room for improvement on how to model them and integrate them effectively. This paper proposes a novel computation model to predict eye fixations, which adopts a multiresolution convolutional neural network (Mr-CNN) to infer these three types of saliency cues from raw image data simultaneously...
November 29, 2016: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/27908161/technical-note-magnetic-field-effects-on-gafchromic-film-response-in-mr-igrt
#4
Francisco J Reynoso, Austen Curcuru, Olga Green, Sasa Mutic, Indra J Das, Lakshmi Santanam
PURPOSE: Magnetokinetic changes may affect crystal orientation and polymerization within the active layer of radiochromic film (RCF). This effect is investigated in a magnetic resonance image-guided radiotherapy unit within the context of film dosimetry. METHODS: Gafchromic EBT2 RCF was irradiated in a 30 × 30 × 30 cm(3) solid water phantom using a Co-60 MRI guided radiotherapy system (B = 0.35 T) under normal operating conditions, and under the exact conditions and setup without a magnetic field...
December 2016: Medical Physics
https://www.readbyqxmd.com/read/27906525/the-clinical-utility-of-qsm-disease-diagnosis-medical-management-and-surgical-planning
#5
REVIEW
Sarah Eskreis-Winkler, Yan Zhang, Jingwei Zhang, Zhe Liu, Alexey Dimov, Ajay Gupta, Yi Wang
Quantitative susceptibility mapping (QSM) is an MR technique that depicts and quantifies magnetic susceptibility sources. Mapping iron, the dominant susceptibility source in the brain, has many important clinical applications. Herein, we review QSM applications in the diagnosis, medical management, and surgical treatment of disease. To assist in early disease diagnosis, QSM can identify elevated iron levels in the motor cortex of amyotrophic lateral sclerosis patients, in the substantia nigra of Parkinson's disease (PD) patients, in the globus pallidus, putamen, and caudate of Huntington's disease patients, and in the basal ganglia of Wilson's disease patients...
December 1, 2016: NMR in Biomedicine
https://www.readbyqxmd.com/read/27899330/mr-visible-localization-device-for-radiographic-pathologic-correlation-of-surgical-specimens
#6
Sonja Kinner, Tilman B Schubert, Elisabetta A Nocerino, Shannon Hynes, Timothy J Colgan, Agnes G Loeffler, Christopher Brace, Scott B Reeder, Emily Winslow
PURPOSE: The detection of small parenchymal hepatic lesions identified by preoperative imaging remains a challenge for traditional pathologic methods in large specimens. We developed a magnetic resonance imaging (MRI) compatible localization device for imaging of surgical specimens aimed to improve identification and localization of hepatic lesions ex vivo. MATERIALS AND METHODS: The device consists of two stationary and one removable MR-visible grids lined with silicone gel, creating an orthogonal 3D matrix for lesion localization...
November 27, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/27894786/mr-angiography-can-guide-ed-management-of-suspected-acute-aortic-dissection
#7
Gary X Wang, Sandeep S Hedgire, Thang Q Le, Jonathan D Sonis, Brian J Yun, Michael H Lev, Ali S Raja, Anand M Prabhakar
BACKGROUND: Aortic dissection is typically evaluated with computed tomography angiography (CTA). However, the feasibility of using magnetic resonance angiography (MRA) in the ED is unclear. This study examined the indications and outcomes of MRA in suspected aortic dissection evaluation in the ED. METHODS: An IRB approved review identified patients who underwent MRA in the ED for acute thoracic aortic dissection from January 2010 to June 2016. Demographics, clinical assessment, CTA contraindications, outcomes, and ED disposition were analyzed...
November 17, 2016: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/27890183/imaging-evaluation-and-treatment-of-vascular-lesions-at-the-skull-base
#8
REVIEW
Gaurav Jindal, Timothy Miller, Prashant Raghavan, Dheeraj Gandhi
A wide range of congenital and acquired vascular entities may occur in the skull base. Although some are diagnosed incidentally and merit no treatment, others may require surgical or image-guided endovascular or percutaneous approaches for management. The complex anatomy of the skull base can make diagnosis challenging. A combination of computed tomography scans and MR imaging, and catheter angiography may be required for diagnosis and mapping. Endovascular treatment plays an important part in many of the acquired vascular lesions, such as vascular neoplasms and traumatic dissections/aneurysms...
January 2017: Radiologic Clinics of North America
https://www.readbyqxmd.com/read/27886557/upconversion-optical-magnetic-resonance-imaging-guided-small-tumor-detection-and-in%C3%A2-vivo-tri-modal-bioimaging-based-on-high-performance-luminescent-nanorods
#9
Zhenluan Xue, Zhigao Yi, Xiaolong Li, Youbin Li, Mingyang Jiang, Hongrong Liu, Songjun Zeng
In this work, we demonstrated multifunctional NaYbF4: Tm(3+)/Gd(3+) upconversion (UC) nanorods (UCNRs) with near-infrared (NIR)-to-NIR emission and controlled phase and size for UC optical and T1/T2 dual-weighted magnetic resonance (MR) imaging-guided small tumor detection and tri-modal bioimaging. Cell toxicity and post-injection histology results revealed that our designed UCNRs present low biotoxicity and good biocompatibility in living animals. Real-time tracking based on UCNRs in living mice demonstrated that the UCNRs were mainly accumulated in the reticuloendothelial system (RES) and excreted through the hepatic pathway...
November 17, 2016: Biomaterials
https://www.readbyqxmd.com/read/27882240/t2-based-temperature-monitoring-in-bone-marrow-for-mr-guided-focused-ultrasound
#10
Eugene Ozhinsky, Misung Han, Matthew Bucknor, Roland Krug, Viola Rieke
BACKGROUND: Current clinical protocols for MR-guided focused ultrasound (MRgFUS) treatment of osseous lesions, including painful bone metastases and osteoid osteomas, rely on measurement of the temperature change in adjacent muscle to estimate the temperature of the bone. The goal of this study was to determine if T2-based thermometry could be used to monitor the temperature change in bone marrow during focused ultrasound ablation of bone lesions. METHODS: We investigated the dependence of T2 on temperature in ex vivo bovine yellow bone marrow at 3T and studied the influence of acquisition parameters on the T2 measurements...
2016: Journal of Therapeutic Ultrasound
https://www.readbyqxmd.com/read/27871928/the-effect-of-dutasteride-on-mri-defined-prostate-cancer-lesions-mapped-magnetic-resonance-imaging-in-primary-prostate-cancer-after-exposure-to-dutasteride-a-randomized-placebo-controlled-double-blind-clinical-trial
#11
Caroline M Moore, Nicola L Robertson, Fatima Jichi, Adebiyi Damola, Gareth Ambler, Francesco Giganti, Ashley J Ridout, Simon Rj Bott, Mathias Winkler, Hashim U Ahmed, Manit Arya, Anita V Mitra, Neil McCartan, Alex Freeman, Charles Jameson, Ramiro Castro, Giulio Gambarota, Brandon J Whitcher, Clare Allen, Alex Kirkham, Mark Emberton
PURPOSE: Dutasteride is licensed for symptomatic benign prostatic hyperplasia, and has been associated with a lower progression rate in low-risk prostate cancer. We have evaluated the effect of dutasteride on prostate cancer volume as assessed by T2-weighted Magnetic Resonance Imaging (MRI). MATERIALS AND METHODS: In this randomized, double-blind, placebo-controlled trial, men with biopsy-proven low-intermediate risk prostate cancer (up to Gleason 3+4 and PSA up to 15 ng/ml) who had an MR visible lesion of >/= 0...
November 18, 2016: Journal of Urology
https://www.readbyqxmd.com/read/27871000/comparison-of-atlas-based-techniques-for-whole-body-bone-segmentation
#12
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/27870618/spinal-injections-for-pain-management
#13
William E Palmer
Image-guided spinal injection is commonly performed in symptomatic patients to decrease pain severity, confirm the pain generator, and delay or avoid surgery. This article focuses on the radiologist as spine interventionist and addresses the following four topics relevant to the radiologist who performs corticosteroid injections for pain management: (a) the rationale behind corticosteroid injection, (b) the interaction with patients, (c) the role of imaging in procedural selection and planning, and (d) the pearls and pitfalls of fluoroscopically guided injections...
December 2016: Radiology
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/27863908/role-of-echocardiography-for-catheter-based-management-of-valvular-heart-disease
#15
REVIEW
Takahiro Shiota
Catheter-based treatment of valvular heart disease, such as transvalvular aortic valve replacement (TAVR) or mitral clip procedure, has been increasingly accepted as a treatment choice for the past several years. Such new treatment options have been changing the management of patients with valvular heart disease drastically while socio-economic factors regarding their application need to be taken into consideration. The use of echocardiography, including transesophageal echocardiography (TEE), for such catheter-based treatments is essential for the success of the procedures...
November 15, 2016: Journal of Cardiology
https://www.readbyqxmd.com/read/27861327/spinal-laser-interstitial-thermal-therapy-a-novel-alternative-to-surgery-for-metastatic-epidural-spinal-cord-compression
#16
Claudio E Tatsui, Sun-Ho Lee, Behrang Amini, Ganesh Rao, Dima Suki, Marilou Oro, Paul D Brown, Amol J Ghia, Shreyas Bhavsar, Keyuri Popat, Laurence D Rhines, R Jason Stafford, Jing Li
BACKGROUND: Although surgery followed by radiation effectively treats metastatic epidural compression, the ideal surgical approach should enable fast recovery and rapid institution of radiation and systemic therapy directed at the primary tumor. OBJECTIVE: To assess spinal laser interstitial thermotherapy (SLITT) as an alternative to surgery monitored in real time by thermal magnetic resonance (MR) images. METHODS: Patients referred for spinal metastasis without motor deficits underwent MR-guided SLITT, followed by stereotactic radiosurgery...
December 2016: Neurosurgery
https://www.readbyqxmd.com/read/27861322/laser-ablation-of-newly-diagnosed-malignant-gliomas-a-meta-analysis
#17
Michael E Ivan, Alireza M Mohammadi, Nicoleta De Deugd, Joshua Reyes, Gregor Rodriguez, Ashish Shah, Gene H Barnett, Ricardo J Komotar
BACKGROUND: Magnetic resonance-guided laser-interstitial thermotherapy (MR-LITT) is a minimally invasive technique that shows promise in neuro-oncology because of its superiority in delivering precise minimally invasive thermal energy with minimal collateral damage. OBJECTIVE: In this analysis, we investigate initial data on the use of MR-LITT in the treatment of newly diagnosed high-grade gliomas. METHODS: With the use of the PubMed, OVID, and Google-scholar database systems, a comprehensive search of the English literature was performed...
December 2016: Neurosurgery
https://www.readbyqxmd.com/read/27861232/safety-and-efficacy-of-magnetic-resonance-guided-vacuum-assisted-large-volume-breast-biopsy-mr-guided-valb
#18
Simone Schrading, Kevin Strobel, Annika Keulers, Timm Dirrichs, Christiane K Kuhl
OBJECTIVE: Magnetic resonance (MR)-guided vacuum-biopsy is technically demanding and may fail depending on target-lesion size or breast size, and location of lesions within the breast. We developed an MR-guided vacuum-assisted biopsy protocol that collects larger amounts of tissue, aiming at an at least partial or complete ablation of the target-lesion, just as it is intended during surgical (excisional) biopsy. Rationale is to avoid biopsy failures (false-negative results due to undersampling) by collecting larger amounts of tissue...
November 17, 2016: Investigative Radiology
https://www.readbyqxmd.com/read/27861110/in-bore-3-t-mr-guided-transrectal-targeted-prostate-biopsy-prostate-imaging-reporting-and-data-system-version-2-based-diagnostic-performance-for-detection-of-prostate-cancer
#19
Nelly Tan, Wei-Chan Lin, Pooria Khoshnoodi, Nazanin H Asvadi, Jeffrey Yoshida, Daniel J A Margolis, David S K Lu, Holden Wu, Kyung Hyun Sung, David Y Lu, Jaioti Huang, Steven S Raman
Purpose To determine the diagnostic yield of in-bore 3-T magnetic resonance (MR) imaging-guided prostate biopsy and stratify performance according to Prostate Imaging Reporting and Data System (PI-RADS) versions 1 and 2. Materials and Methods This study was HIPAA compliant and institution review board approved. In-bore 3-T MR-guided prostate biopsy was performed in 134 targets in 106 men who (a) had not previously undergone prostate biopsy, (b) had prior negative biopsy findings with increased prostate-specific antigen (PSA) level, or (c) had a prior history of prostate cancer with increasing PSA level...
November 18, 2016: Radiology
https://www.readbyqxmd.com/read/27860551/congenital-variants-and-anomalies-of-the-aortic-arch
#20
Kate Hanneman, Beverley Newman, Frandics Chan
Congenital variants and anomalies of the aortic arch are important to recognize as they may be associated with vascular rings, congenital heart disease, and chromosomal abnormalities, and can have important implications for prognosis and management. The purpose of this article is to review cross-sectional imaging techniques used in the evaluation of the aortic arch, describe the embryology and anatomy of the aortic arch system, discuss aortic arch variants and anomalies, and review other malformations of the aortic arch, including interrupted aortic arch, hypoplastic aortic arch, and aortic coarctation...
November 18, 2016: Radiographics: a Review Publication of the Radiological Society of North America, Inc
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