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https://www.readbyqxmd.com/read/28740928/magnetic-resonance-imaging-guided-reirradiation-of-recurrent-and-second-primary-head-and-neck-cancer
#1
Allen M Chen, Minsong Cao, Sophia Hsu, James Lamb, Argin Mikaeilian, Yingli Yang, Nzhde Agazaryan, Daniel A Low, Michael L Steinberg
PURPOSE: To report a single-institutional experience using magnetic resonance imaging (MRI) guided radiation therapy for the reirradiation of recurrent and second cancers of the head and neck. METHODS AND MATERIALS: Between October 2014 and August 2016, 13 consecutive patients with recurrent or new primary cancers of the head and neck that occurred in a previously irradiated field were prospectively enrolled in an institutional registry trial to investigate the feasibility and efficacy of MRI guided radiation therapy using a 0...
April 2017: Advances in Radiation Oncology
https://www.readbyqxmd.com/read/28739392/large-improvement-of-rf-transmission-efficiency-and-reception-sensitivity-for-human-in-vivo-31-p-mrs-imaging-using-ultrahigh-dielectric-constant-materials-at-7t
#2
Byeong-Yeul Lee, Xiao-Hong Zhu, Sebastian Rupprecht, Michael T Lanagan, Qing X Yang, Wei Chen
In vivo(31)P MRS provides a unique and important imaging tool for studying high-energy phosphate metabolism and bioenergetics noninvasively. However, compared to (1)H MRS, (31)P MRS with a relatively low gyromagnetic ratio (γ) has a lower and limited sensitivity even at ultrahigh field. The proof of concept has been recently demonstrated that the use of high dielectric constant (HDC) materials between RF coil and object sample could increase MRI signal and reduce required RF transmission power for reaching the same RF pulse flip angle in the region of interest...
July 21, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28725923/assessing-3d-t2-fse-sequence-for-identification-of-the-normal-appendix-working-toward-a-single-sequence-mr-appendicitis-protocol
#3
Nattinee Leelakanok, Andrew S Phelps, Matthew A Zapala, Kambrie Kato, Michael Ohliger, Yi Li, Jesse Courtier
PURPOSES: To assess the ability of a single isotropic 3D T2 FSE sequence to identify the normal appendix in children with potential implication as alternative second-line modality in pediatric appendicitis. MATERIALS AND METHODS: Retrospective review of MR abdomino-pelvis or pelvis in children from Oct 2014-Dec 2016 was done. Only exams with 3D T2 FSE sequence performed on a single scanner type were selected. Patients with history of post appendectomy, studies in which field of view did not include ileocecal valve, with technical and protocol errors, or with fat-saturated acquisition were excluded...
July 19, 2017: Emergency Radiology
https://www.readbyqxmd.com/read/28722095/-correlation-of-mri-apparent-diffusion-coeffcient-with-molecular-marker-ki-67-in-gastric-cancer
#4
Guodian Zheng, Xiangdong Cheng, Lijing Wang, Zhiyuan Xu, Xuning Gao, Pengfei Yu, Hang Lyu, Ting Huang, Jiahui Chen
OBJECTIVES: To study the correlation between MRI apparent diffusion coefficient (ADC) and expression of Ki-67 in gastric cancers, and to investigate the application of ADC value in diagnosing the malignance of gastric cancer. METHODS: A retrospective cohort analysis was performed on 87 gastric cancer patients who received MRI examination and radical resection at Zhejiang Provincial Hospital of Traditional Chinese Medicine from November 2014 to August 2015. All the postoperative resected samples were confirmed as gastric cancer...
July 25, 2017: Zhonghua Wei Chang Wai Ke za Zhi, Chinese Journal of Gastrointestinal Surgery
https://www.readbyqxmd.com/read/28714120/partial-fourier-techniques-in-single-shot-cross-term-spatiotemporal-encoded-mri
#5
Zhiyong Zhang, Lucio Frydman
PURPOSE: Cross-term spatiotemporal encoding (xSPEN) is a single-shot approach with exceptional immunity to field heterogeneities, the images of which faithfully deliver 2D spatial distributions without requiring a priori information or using postacquisition corrections. xSPEN, however, suffers from signal-to-noise ratio penalties due to its non-Fourier nature and due to diffusion losses-especially when seeking high resolution. This study explores partial Fourier transform approaches that, acting along either the readout or the spatiotemporally encoded dimensions, reduce these penalties...
July 16, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28706852/neurological-software-tool-for-reliable-atrophy-measurement-neurostream-of-the-lateral-ventricles-on-clinical-quality-t2-flair-mri-scans-in-multiple-sclerosis
#6
Michael G Dwyer, Diego Silva, Niels Bergsland, Dana Horakova, Deepa Ramasamy, Jaqueline Durfee, Manuela Vaneckova, Eva Havrdova, Robert Zivadinov
BACKGROUND: There is a need for a brain volume measure applicable to the clinical routine scans. Nearly every multiple sclerosis (MS) protocol includes low-resolution 2D T2-FLAIR imaging. OBJECTIVES: To develop and validate cross-sectional and longitudinal brain atrophy measures on clinical-quality T2-FLAIR images in MS patients. METHODS: A real-world dataset from 109 MS patients from 62 MRI scanners was used to develop a lateral ventricular volume (LVV) algorithm with a longitudinal Jacobian-based extension, called NeuroSTREAM...
2017: NeuroImage: Clinical
https://www.readbyqxmd.com/read/28692129/distortion-free-diffusion-mri-using-an-mri-guided-tri-cobalt-60-radiotherapy-system-sequence-verification-and-preliminary-clinical-experience
#7
Yu Gao, Fei Han, Ziwu Zhou, Minsong Cao, Tania Kaprealian, Mitchell Kamrava, Chenyang Wang, John Neylon, Daniel A Low, Yingli Yang, Peng Hu
PURPOSE: Monitoring tumor response during the course of treatment and adaptively modifying treatment plan based on tumor biological feedback may represent a new paradigm for radiotherapy. Diffusion MRI has shown great promises in assessing and predicting tumor response to radiotherapy. However, the conventional diffusion-weighted single-shot echo-planar-imaging (DW-ssEPI) technique suffers from limited resolution, severe distortion and possibly inaccurate ADC at low field strength. The purpose of this work is to develop a reliable, accurate and distortion-free diffusion MRI technique that is practicable for longitudinal tumor response evaluation and adaptive radiotherapy on a 0...
July 10, 2017: Medical Physics
https://www.readbyqxmd.com/read/28686805/a-generalized-ratiometric-chemical-exchange-saturation-transfer-cest-mri-approach-for-mapping-renal-ph-using-iopamidol
#8
Yin Wu, Iris Y Zhou, Takahiro Igarashi, Dario L Longo, Silvio Aime, Phillip Zhe Sun
PURPOSE: To extend the pH detection range of iopamidol-based ratiometric chemical exchange saturation transfer (CEST) MRI at sub-high magnetic field and establish quantitative renal pH MRI. METHODS: Chemical exchange saturation transfer imaging was performed on iopamidol phantoms with pH of 5.5 to 8.0 and in vivo on rat kidneys (n = 5) during iopamidol administration at a 4.7 T. Iopamidol CEST effects were described using a multipool Lorentzian model. A generalized ratiometric analysis was conducted by ratioing resolved iopamidol CEST effects at 4...
July 7, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28685470/construction-of-0-15-tesla-overhauser-enhanced-mri
#9
Yuumi Tokunaga, Motonao Nakao, Tatsuya Naganuma, Kazuhiro Ichikawa
Overhauser enhanced MRI (OMRI) is one of the free radical imaging technologies and has been used in biomedical research such as for partial oxygen measurements in tumor, and redox status in acute oxidative diseases. The external magnetic field of OMRI is frequently in the range of 5-10 mTesla to ensure microwave penetration into small animals, and the S/N ratio is limited. In this study, a 0.15 Tesla OMRI was constructed and tested to improve the S/N ratio for a small sample, or skin measurement. Specification of the main magnet was as follows: 0...
2017: Advances in Experimental Medicine and Biology
https://www.readbyqxmd.com/read/28681515/accuracy-of-open-magnetic-resonance-imaging-for-guiding-injection-of-the-equine-deep-digital-flexor-tendon-within-the-hoof
#10
Lauren M Groom, Nathaniel A White, M Norris Adams, Jennifer G Barrett
Lesions of the distal deep digital flexor tendon (DDFT) are frequently diagnosed using MRI in horses with foot pain. Intralesional injection of biologic therapeutics shows promise in tendon healing; however, accurate injection of distal deep digital flexor tendon lesions within the hoof is difficult. The aim of this experimental study was to evaluate accuracy of a technique for injection of the deep digital flexor tendon within the hoof using MRI-guidance, which could be performed in standing patients. We hypothesized that injection of the distal deep digital flexor tendon within the hoof could be accurately guided using open low-field MRI to target either the lateral or medial lobe at a specific location...
July 6, 2017: Veterinary Radiology & Ultrasound
https://www.readbyqxmd.com/read/28681390/a-deep-feature-fusion-methodology-for-breast-cancer-diagnosis-demonstrated-on-three-imaging-modality-datasets
#11
Natalia Antropova, Benjamin Q Huynh, Maryellen L Giger
Deep learning methods for radiomics/computer-aided diagnosis (CADx) are often prohibited by small datasets, long computation time, and the need for extensive image preprocessing. We present a methodology that extracts and pools low- to mid-level features using a pre-trained convolutional neural network and fuses them with handcrafted radiomic features computed using conventional CADx methods. Our fusion-based method demonstrates significant improvements to previous breast cancer CADx methods across three clinical imaging modalities (dynamic contrast-enhanced MRI, full-field digital mammography, and ultrasound) in terms of predictive performance in the task of estimating lesion malignancy...
July 6, 2017: Medical Physics
https://www.readbyqxmd.com/read/28670404/role-of-anatomical-landmarks-in-identifying-normal-and-transitional-vertebra-in-lumbar-spine-magnetic-resonance-imaging
#12
Devimeenal Jagannathan, Venkatraman Indiran, Fouzal Hithaya, M Alamelu, S Padmanaban
STUDY DESIGN: Retrospective study. PURPOSE: Identification of transitional vertebra is important in spine imaging, especially in presurgical planning. Pasted images of the whole spine obtained using high-field magnetic resonance imaging (MRI) are helpful in counting vertebrae and identifying transitional vertebrae. Counting vertebrae and identifying transitional vertebrae is challenging in isolated studies of lumbar spine and in studies conducted in low-field MRI...
June 2017: Asian Spine Journal
https://www.readbyqxmd.com/read/28668358/a-new-algebraic-method-for-quantitative-proton-density-mapping-using-multi-channel-coil-data
#13
Dietmar Cordes, Zhengshi Yang, Xiaowei Zhuang, Karthik Sreenivasan, Virendra Mishra, Le H Hua
A difficult problem in quantitative MRI is the accurate determination of the proton density, which is an important quantity in measuring brain tissue organization. Recent progress in estimating proton density in vivo has been based on using the inverse linear relationship between the longitudinal relaxation rate T1 and proton density. In this study, the same type of relationship is being used, however, in a more general framework by constructing 3D basis functions to model the receiver bias field. The novelty of this method is that the basis functions developed are suitable to cover an entire range of inverse linearities between T1 and proton density...
June 23, 2017: Medical Image Analysis
https://www.readbyqxmd.com/read/28656357/magnetic-resonance-imaging-in-evaluation-of-tunnel-diameters-prior-to-revision-acl-reconstruction-a-comparison-to-computed-tomography
#14
Björn Holger Drews, Cornelia Merz, Jochen Huth, Daniel Gulkin, Joachim Guelke, Florian Gebhard, Frieder Mauch
OBJECTIVE: Revision ACL reconstruction is becoming more frequent because of a 10% rate of re-ruptures and insufficiencies. Currently, computed tomography (CT) represents the gold standard in detecting and measuring the tunnels of the initial ACL reconstruction. The purpose of this study was to compare measurement results of CT and thin-sliced MRI sequences, which were modified to a high soft tissue-bone contrast. MATERIALS AND METHODS: Prior to an ACL revision surgery, 16 consecutive patients had an MRI in addition to the standard CT scan...
June 27, 2017: Skeletal Radiology
https://www.readbyqxmd.com/read/28653507/t1-nuclear-magnetic-relaxation-dispersion-of-hyperpolarized-sodium-and-cesium-hydrogencarbonate-13-c
#15
Francisco M Martínez-Santiesteban, Thien Phuoc Dang, Heeseung Lim, Albert P Chen, Timothy J Scholl
In vivo pH mapping in tissue using hyperpolarized hydrogencarbonate-(13) C has been proposed as a method to study tumor growth and treatment and other pathological conditions related to pH changes. The finite spin-lattice relaxation times (T1 ) of hyperpolarized media are a significant limiting factor for in vivo imaging. Relaxation times can be measured at standard magnetic fields (1.5 T, 3.0 T etc.), but no such data are available at low fields, where T1 values can be significantly shorter. This information is required to determine the potential loss of polarization as the agent is dispensed and transported from the polarizer to the MRI scanner...
June 27, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28651245/high-resolution-hyperpolarized-in-vivo-metabolic-13-c-spectroscopy-at-low-magnetic-field-48-7mt-following-murine-tail-vein-injection
#16
Aaron M Coffey, Matthew A Feldman, Roman V Shchepin, Danila A Barskiy, Milton L Truong, Wellington Pham, Eduard Y Chekmenev
High-resolution (13)C NMR spectroscopy of hyperpolarized succinate-1-(13)C-2,3-d2 is reported in vitro and in vivo using a clinical-scale, biplanar (80cm-gap) 48.7mT permanent magnet with a high homogeneity magnetic field. Non-localized (13)C NMR spectra were recorded at 0.52MHz resonance frequency over the torso of a tumor-bearing mouse every 2s. Hyperpolarized (13)C NMR signals with linewidths of ∼3Hz (corresponding to ∼6ppm) were recorded in vitro (2mL in a syringe) and in vivo (over a mouse torso). Comparison of the full width at half maximum (FWHM) for (13)C NMR spectra acquired at 48...
June 15, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28651069/automatic-mpst-cut-for-segmentation-of-carpal-bones-from-mr-volumes
#17
Laura Gemme, Sonia Nardotto, Silvana G Dellepiane
In the context of rheumatic diseases, several studies suggest that Magnetic Resonance Imaging (MRI) allows the detection of the three main signs of Rheumatoid Arthritis (RA) at higher sensitivities than available through conventional radiology. The rapid, accurate segmentation of bones is an essential preliminary step for quantitative diagnosis, erosion evaluation, and multi-temporal data fusion. In the present paper, a new, semi-automatic, 3D graph-based segmentation method to extract carpal bone data is proposed...
June 12, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28638673/monitoring-of-cellular-changes-in-the-bone-marrow-following-pth-1-34-treatment-of-ovx-rats-using-a-portable-stray-field-nmr-scanner
#18
Inbar Hillel, Itzhak Binderman, Yifat Sarda, Uri Nevo
Osteoporosis is characterized by reduction in trabecular bone in conjunction with increased marrow cell adiposity. While these changes occur within weeks, monitoring of treatment efficacy as performed by DEXA is sensitive only to long-term changes. MRI is sensitive to bone marrow changes but is less affordable. In a recent study, we have shown that a stray-field NMR can monitor bone marrow cellular changes that are related to osteoporosis. Objectives. To demonstrate sensitivity of a low-field tabletop NMR scanner to bone marrow dynamics following hormonal treatment in rats...
2017: Journal of Osteoporosis
https://www.readbyqxmd.com/read/28632688/high-quality-3-dimensional-1h-magnetic-resonance-spectroscopic-imaging-of-the-prostate-without-endorectal-receive-coil-using-a-semi-laser-sequence
#19
Nassim Tayari, Isabell K Steinseifer, Kirsten M Selnæs, Tone F Bathen, Marnix C Maas, Arend Heerschap
OBJECTIVES: Inclusion of 3-dimensional H magnetic resonance spectroscopic imaging (3D-H-MRSI) in routine multiparametric MRI of the prostate requires good quality spectra and easy interpretable metabolite maps of the whole organ obtained without endorectal coil in clinically feasible acquisition times. We evaluated if a semi-LASER pulse sequence with gradient offset independent adiabaticity refocusing pulses (GOIA-sLASER) for volume selection can meet these requirements. MATERIALS AND METHODS: Thirteen patients with suspicion of prostate cancer and 1 patient known to have prostate cancer were examined at 3 T with a multichannel body-receive coil...
June 19, 2017: Investigative Radiology
https://www.readbyqxmd.com/read/28631204/adaptive-step-size-lms-improves-ecg-detection-during-mri-at-1-5-and-3%C3%A2-t
#20
André Guillou, Jean-Marc Sellal, Sarah Ménétré, Grégory Petitmangin, Jacques Felblinger, Laurent Bonnemains
OBJECTIVE: We describe a new real-time filter to reduce artefacts on electrocardiogram (ECG) due to magnetic field gradients during MRI. The proposed filter is a least mean square (LMS) filter able to continuously adapt its step size according to the gradient signal of the ongoing MRI acquisition. MATERIALS AND METHODS: We implemented this filter and compared it, within two databases (at 1.5 and 3 T) with over 6000 QRS complexes, to five real-time filtering strategies (no filter, low pass filter, standard LMS, and two other filters optimized within the databases: optimized LMS, and optimized Kalman filter)...
June 19, 2017: Magma
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