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https://www.readbyqxmd.com/read/28813574/dynamic-imaging-of-the-eye-optic-nerve-and-extraocular-muscles-with-golden-angle-radial-mri
#1
Saikat Sengupta, David S Smith, Alex K Smith, E Brian Welch, Seth A Smith
Purpose: The eye and its accessory structures, the optic nerve and the extraocular muscles, form a complex dynamic system. In vivo magnetic resonance imaging (MRI) of this system in motion can have substantial benefits in understanding oculomotor functioning in health and disease, but has been restricted to date to imaging of static gazes only. The purpose of this work was to develop a technique to image the eye and its accessory visual structures in motion. Methods: Dynamic imaging of the eye was developed on a 3-Tesla MRI scanner, based on a golden angle radial sequence that allows freely selectable frame-rate and temporal-span image reconstructions from the same acquired data set...
August 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28812203/assessment-of-methodologies-to-calculate-intraventricular-pressure-differences-in-computational-models-and-patients
#2
Francisco J Londono-Hoyos, Abigail Swillens, Joris Van Cauwenberge, Brett Meyers, Maheswara Reddy Koppula, Pavlos Vlachos, Julio A Chirinos, Patrick Segers
Intraventricular pressure differences (IVPDs) govern left ventricular (LV) efficient filling and are a significant determinant of LV diastolic function. Our primary aim is to assess the performance of available methods (color M-mode (CMM) and 1D/2D MRI-based methods) to determine IVPDs from intracardiac flow measurements. Performance of three methods to calculate IVPDs was first investigated via an LV computational fluid dynamics (CFD) model. CFD velocity data were derived along a modifiable scan line, mimicking ultrasound/MRI acquisition of 1D (IVPDCMM/IVPD1D MRI) and 2D (IVPD2D MRI) velocity-based IVPD information...
August 16, 2017: Medical & Biological Engineering & Computing
https://www.readbyqxmd.com/read/28812002/image-guided-thermal-ablation-with-mr-based-thermometry
#3
REVIEW
Mingming Zhu, Ziqi Sun, Chin K Ng
Thermal ablation techniques such as radiofrequency, microwave, high intensity focused ultrasound (HIFU) and laser have been used as minimally invasive strategies for the treatment of variety of cancers. MR thermometry methods are readily available for monitoring thermal distribution and deposition in real time, leading to decrease of incidents of normal tissue damage around targeted lesion. HIFU and laser-induced thermal therapy (LITT) are the two widely accepted tumor ablation techniques because of their compatibility with MR systems...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28809668/tractography-based-score-for-learning-effective-connectivity-from-multimodal-imaging-data-using-dynamic-bayesian-networks
#4
Shilpa Dang, Santanu Chaudhury, Brejesh Lall, Prasun K Roy
OBJECTIVE: Effective connectivity (EC) is the methodology for determining functional-integration among the functionally-active segregated regions of the brain. By definition [1] EC is "the causal influence exerted by one neuronal group on another" which is constrained by anatomical connectivity (AC) (axonal connections). AC is necessary for EC but does not fully determine it, because synaptic communication occurs dynamically in a context-dependent fashion. Although there is a vast emerging evidence of structure-function relationship using multimodal imaging studies, till date only a few studies have done joint modelling of the two modalities: functional MRI (fMRI) and Diffusion Tensor Imaging (DTI)...
August 10, 2017: IEEE Transactions on Bio-medical Engineering
https://www.readbyqxmd.com/read/28809641/cementless-total-hip-arthroplasty-in-primary-myelofibrosis-a-case-report
#5
S Brodt, E Eigendorff, G Matziolis
There is a great deal of data available, in part contradictory, on the best fixation technique to use for total hip arthroplasty (THA) in hip osteoarthritis. Both the cementless and the cemented versions offer excellent long-term outcomes - if the respective technique is applied correctly. However, as far as we know, no recommendation has been made regarding cemented vs. cementless THA in primary myelofibrosis. The case described here concerns a very active 76-year-old patient with primary myelofibrosis. This is a rare hematological disease...
2017: Acta Chirurgiae Orthopaedicae et Traumatologiae Cechoslovaca
https://www.readbyqxmd.com/read/28808823/vessel-wall-characterization-using-quantitative-mri-what-s-in-a-number
#6
REVIEW
Bram F Coolen, Claudia Calcagno, Pim van Ooij, Zahi A Fayad, Gustav J Strijkers, Aart J Nederveen
The past decade has witnessed the rapid development of new MRI technology for vessel wall imaging. Today, with advances in MRI hardware and pulse sequences, quantitative MRI of the vessel wall represents a real alternative to conventional qualitative imaging, which is hindered by significant intra- and inter-observer variability. Quantitative MRI can measure several important morphological and functional characteristics of the vessel wall. This review provides a detailed introduction to novel quantitative MRI methods for measuring vessel wall dimensions, plaque composition and permeability, endothelial shear stress and wall stiffness...
August 14, 2017: Magma
https://www.readbyqxmd.com/read/28807564/reduced-metallic-artefacts-in-3%C3%A2-t-knee-mri-using-fast-spin-echo-multi-point-dixon-compared-to-fast-spin-echo-t2-weighted-sequences
#7
H J Park, S Y Lee, S H Choi, H P Hong, Y J Choi, M S Kim
AIM: To compare multi-point Dixon magnetic resonance imaging (MRI) and fast spin-echo (FSE) T2-weighted imaging (WI) with regard to the size of metallic artefacts when imaging the knee joint. MATERIALS AND METHODS: A total of 42 patients who underwent anterior cruciate ligament (ACL) reconstruction and follow-up imaging with 3 T MRI using the multi-point Dixon technique was included in this retrospective study. The maximal distance of the image distortion area around the metallic artefact was measured (interference screw of femoral tunnel area) on sagittal images of both FSE T2WI (T2WI and fat-suppressed [FS] T2WI) and multi-point Dixon (water only image and in-phase image) sequences...
August 11, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28807441/whole-body-dose-and-energy-measurements-in-radiotherapy-by-a-combination-of-lif-mg-cu-p-and-lif-mg-ti
#8
Pascal Hauri, Uwe Schneider
PURPOSE: Long-term survivors of cancer who were treated with radiotherapy are at risk of a radiation-induced tumor. Hence, it is important to model the out-of-field dose resulting from a cancer treatment. These models have to be verified with measurements, due to the small size, the high sensitivity to ionizing radiation and the tissue-equivalent composition, LiF thermoluminescence dosimeters (TLD) are well-suited for out-of-field dose measurements. However, the photon energy variation of the stray dose leads to systematic dose errors caused by the variation in response with radiation energy of the TLDs...
August 11, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28806856/direct-cell-labeling-to-image-transplanted-stem-cells-in-real-time-using-a-dual-contrast-mri-technique
#9
Ethel J Ngen, Yoshinori Kato, Dmitri Artemov
Exogenous direct cell labeling with superparamagnetic iron oxide nanoparticles (SPIONs) is currently the most employed cell-labeling technique for tracking transplanted cells using magnetic resonance imaging (MRI). Although SPION-based cell labeling is effective for monitoring cell delivery and migration, monitoring cell survival is still a challenge. This unit describes an MRI technique that permits detection of the delivery, migration, and death of transplanted cells. This dual-contrast technique involves labeling cells with two different classes of MRI contrast agents, possessing different diffusion coefficients: SPIONs (T2 /T2(*) contrast agents, with lower diffusion coefficients) and gadolinium chelates (T1 contrast agents, with higher diffusion coefficients)...
August 14, 2017: Current Protocols in Stem Cell Biology
https://www.readbyqxmd.com/read/28806629/aseptic-meningitis-in-adults-and-children-diagnostic-and-management-challenges
#10
Bhavarth Shukla, Elizabeth A Aguilera, Lucrecia Salazar, Susan H Wootton, Quanhathai Kaewpoowat, Rodrigo Hasbun
BACKGROUND: Aseptic meningitis represents a common diagnostic and management dilemma to clinicians. OBJECTIVES: To compare the clinical epidemiology, diagnostic evaluations, management, and outcomes between adults and children with aseptic meningitis. STUDY DESIGN: We conducted a retrospective study from January 2005 through September 2010 at 9 Memorial Hermann Hospitals in Houston, TX. Patients age≥2months who presented with community-acquired aseptic meningitis with a CSF white blood cell count >5cells/mm(3) and a negative Gram stain and cultures were enrolled...
August 4, 2017: Journal of Clinical Virology: the Official Publication of the Pan American Society for Clinical Virology
https://www.readbyqxmd.com/read/28806322/reduced-field-of-view-diffusion-weighted-magnetic-resonance-imaging-of-the-prostate-at-3-tesla-comparison-with-standard-echo-planar-imaging-technique-for-image-quality-and-tumor-assessment
#11
Tsutomu Tamada, Justin M Ream, Ankur M Doshi, Samir S Taneja, Andrew B Rosenkrantz
OBJECTIVE: The purpose of this study was to compare image quality and tumor assessment at prostate magnetic resonance imaging (MRI) between reduced field-of-view diffusion-weighted imaging (rFOV-DWI) and standard DWI (st-DWI). METHODS: A total of 49 patients undergoing prostate MRI and MRI/ultrasound fusion-targeted biopsy were included. Examinations included st-DWI (field of view [FOV], 200 × 200 mm) and rFOV-DWI (FOV, 140 × 64 mm) using a 2-dimensional (2D) spatially-selective radiofrequency pulse and parallel transmission...
August 12, 2017: Journal of Computer Assisted Tomography
https://www.readbyqxmd.com/read/28805936/characterizing-hypoxia-in-human-glioma-a-simultaneous-multimodal-mri-and-pet-study
#12
Christine Preibisch, Kuangyu Shi, Anne Kluge, Mathias Lukas, Benedikt Wiestler, Jens Göttler, Jens Gempt, Florian Ringel, Mohamed Al Jaberi, Jürgen Schlegel, Bernhard Meyer, Claus Zimmer, Thomas Pyka, Stefan Förster
Hypoxia plays an important role for the prognosis and therapy response of cancer. Thus, hypoxia imaging would be a valuable tool for pre-therapeutic assessment of tumor malignancy. However, there is no standard validated technique for clinical application available yet. Therefore, we performed a study in 12 patients with high-grade glioma, where we directly compared the two currently most promising techniques, namely the MR-based relative oxygen extraction fraction (MR-rOEF) and the PET hypoxia marker H-1-(3-[(18) F]-fluoro-2-hydroxypropyl)-2-nitroimidazole ([(18) F]-FMISO)...
August 14, 2017: NMR in Biomedicine
https://www.readbyqxmd.com/read/28805093/monitoring-disease-progression-in-spinocerebellar-ataxias-implications-for-treatment-and-clinical-research
#13
Lidia Sarro, Lorenzo Nanetti, Anna Castaldo, Caterina Mariotti
Spinocerebellar ataxias (SCAs) are autosomal dominant diseases characterized by progressive gait and limb incoordination, disequilibrium, dysarthria, and eye movement disturbances. Approximately 40 genetic subtypes of SCAs are known and classified according to the causative disease gene/locus. With the possibility of the specific genetic diagnosis in patients and at-risk family members, several clinical scales and functional tests have been validated and used in ataxic patients with the purposes of measuring the entity of disease progression in natural history studies and the possible slowing of neurological impairment in therapeutic trials...
August 13, 2017: Expert Review of Neurotherapeutics
https://www.readbyqxmd.com/read/28804704/hypoxia-in-cervical-cancer-from-biology-to-imaging
#14
REVIEW
Heidi Lyng, Eirik Malinen
PURPOSE: Hypoxia imaging may improve identification of cervical cancer patients at risk of treatment failure and be utilized in treatment planning and monitoring, but its clinical potential is far from fully realized. Here, we briefly describe the biology of hypoxia in cervix tumors of relevance for imaging, and evaluate positron emission tomography (PET) and magnetic resonance imaging (MRI) techniques that have shown promise for assessing hypoxia in a clinical setting. We further discuss emerging imaging approaches, and how imaging can play a role in future treatment strategies to target hypoxia...
2017: Clinical and Translational Imaging: Reviews in Nuclear Medicine and Molecular Imaging
https://www.readbyqxmd.com/read/28804506/improved-k-t-pca-algorithm-using-artificial-sparsity-in-dynamic-mri
#15
Yiran Wang, Zhifeng Chen, Jing Wang, Lixia Yuan, Ling Xia, Feng Liu
The k-t principal component analysis (k-t PCA) is an effective approach for high spatiotemporal resolution dynamic magnetic resonance (MR) imaging. However, it suffers from larger residual aliasing artifacts and noise amplification when the reduction factor goes higher. To further enhance the performance of this technique, we propose a new method called sparse k-t PCA that combines the k-t PCA algorithm with an artificial sparsity constraint. It is a self-calibrated procedure that is based on the traditional k-t PCA method by further eliminating the reconstruction error derived from complex subtraction of the sampled k-t space from the original reconstructed k-t space...
2017: Computational and Mathematical Methods in Medicine
https://www.readbyqxmd.com/read/28803449/prospective-comparison-between-magnetic-resonance-imaging-and-computed-tomography-in-colorectal-cancer-staging
#16
Frederick H X Koh, Ker-Kan Tan, Lynette L S Teo, Bertrand W L Ang, Yee-Liang Thian
BACKGROUND: Diffusion-weighted (DW) imaging is a functional magnetic resonance imaging (MRI) technique that detects lesions with high cellularity, such as malignant tumours. This prospective study was performed to compare the accuracy of DW-MRI with multidetector computed tomography (MDCT) in staging of colorectal cancer. METHODS: Thirty patients with histologically proven colorectal cancer were prospectively recruited. Each patient underwent both MDCT and DW-MRI of the abdomen-pelvis for primary staging...
August 13, 2017: ANZ Journal of Surgery
https://www.readbyqxmd.com/read/28803444/atypical-parkinsonian-syndromes-a-general-neurologist-s-perspective
#17
REVIEW
Angela B Deutschländer, Owen A Ross, Dennis W Dickson, Zbigniew K Wszolek
The differential diagnosis of atypical parkinsonian syndromes is challenging. These severe and often rapidly progressive neurodegenerative disorders are clinically heterogeneous and show significant phenotypic overlap. Here we review clinical, imaging, neuropathologic and genetic features of multiple system atrophy (MSA), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and frontotemporal lobar degeneration (FTLD). The terms CBD and FTLD refer to pathologically confirmed cases of corticobasal syndrome (CBS) and frontotemporal dementia (FTD)...
August 12, 2017: European Journal of Neurology: the Official Journal of the European Federation of Neurological Societies
https://www.readbyqxmd.com/read/28803112/in-vivo-documentation-of-shape-and-position-changes-of-mri-visible-mesh-placed-in-rectovaginal-septum
#18
Urbankova Iva, Sindhwani Nikhil, Callewaert Geertje, Turri Alice, Rinkijevic Rita, Hympanova Lucie, Feola Andrew, Deprest Jan
BACKGROUND AND OBJECTIVE: Large deformations in synthetic meshes used in pelvic organ prolapse surgery may lead to suboptimal support for the underlying tissue, graft-related complications as well as recurrence. Our aim was to quantify in vivo longitudinal changes in mesh shape and geometry in a large animal model. We compare two commonly used mesh shapes, armed and flat, that are differently affixed. The secondary outcomes were active and passive biomechanical properties. METHODS: A total of 18 animals were used...
August 5, 2017: Journal of the Mechanical Behavior of Biomedical Materials
https://www.readbyqxmd.com/read/28802623/an-analytical-model-which-determines-the-apparent-t1-for-modified-look-locker-inversion-recovery-analysis-of-the-longitudinal-relaxation-under-the-influence-of-discontinuous-balanced-classical-molli-and-spoiled-gradient-echo-readouts
#19
Thomas Kampf, Theresa Reiter, Wolfgang Rudolf Bauer
Quantitative nuclear magnetic resonance imaging (MRI) shifts more and more into the focus of clinical research. Especially determination of relaxation times without/and with contrast agents becomes the foundation of tissue characterization, e.g. in cardiac MRI for myocardial fibrosis. Techniques which assess longitudinal relaxation times rely on repetitive application of readout modules, which are interrupted by free relaxation periods, e.g. the Modified Look-Locker Inversion Recovery = MOLLI sequence. These discontinuous sequences reveal an apparent relaxation time, and, by techniques extrapolated from continuous readout sequences, a putative real T1 is determined...
August 9, 2017: Zeitschrift Für Medizinische Physik
https://www.readbyqxmd.com/read/28802328/hybrid-pet-mri-co-segmentation-based-on-joint-fuzzy-connectedness-and-graph-cut
#20
Arafet Sbei, Khaoula ElBedoui, Walid Barhoumi, Philippe Maksud, Chokri Maktouf
BACKGROUND AND OBJECTIVE: Tumor segmentation from hybrid PET/MRI scans may be highly beneficial in radiotherapy treatment planning. Indeed, it gives for both modalities the suitable information that could make the delineation of tumors more accurate than using each one apart. We aim in this work to propose a co-segmentation method that deals with several challenges, notably the lack of one-to-one correspondence between tumors of the two modalities and the boundaries' smoothing. METHODS: The proposed method is designed to surpass these limits, we propose a segmentation method based on the GCsum(max) technique...
October 2017: Computer Methods and Programs in Biomedicine
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