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https://www.readbyqxmd.com/read/28097250/spinal-cord-compression-from-wegener-s-granulomatosis-an-unusual-presentation
#1
Deb Roy, Prashanth J Rao, Kevin Phan, Ralph J Mobbs, Michael Selby
Wegener's granulomatosis (WG) causing spinal cord compression is very rare with only few cases reported in literature. We present a case report with review of literature. A 55-year-old lady with known WG presented with acute on chronic spinal cord compression. MRI scan revealed spinal cord compression anteriorly and posteriorly at T2-T5 level. Patient underwent urgent surgical decompression with excision of the posterior dural lesion with synthetic duraplasty. Patient made good neurological recovery. Histopathology revealed features consistent with WG...
December 2016: Journal of Spine Surgery (Hong Kong)
https://www.readbyqxmd.com/read/28091590/high-performance-magneto-fluorescent-nanoparticles-assembled-from-terbium-and-gadolinium-1-3-diketones
#2
Rustem Zairov, Asiya Mustafina, Nataliya Shamsutdinova, Irek Nizameev, Beatriz Moreira, Svetlana Sudakova, Sergey Podyachev, Alfia Fattakhova, Gulnara Safina, Ingemar Lundstrom, Aidar Gubaidullin, Alberto Vomiero
Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted...
January 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28090604/xq-nlm-denoising-diffusion-mri-data-via-x-q-space-non-local-patch-matching
#3
Geng Chen, Yafeng Wu, Dinggang Shen, Pew-Thian Yap
Noise is a major issue influencing quantitative analysis in diffusion MRI. The effects of noise can be reduced by repeated acquisitions, but this leads to long acquisition times that can be unrealistic in clinical settings. For this reason, post-acquisition denoising methods have been widely used to improve SNR. Among existing methods, non-local means (NLM) has been shown to produce good image quality with edge preservation. However, currently the application of NLM to diffusion MRI has been mostly focused on the spatial space (i...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/28090247/optimal-parameter-map-estimation-for-shape-representation-a-generative-approach
#4
Shireen Y Elhabian, Praful Agrawal, Ross T Whitaker
Probabilistic label maps are a useful tool for important medical image analysis tasks such as segmentation, shape analysis, and atlas building. Existing methods typically rely on blurred signed distance maps or smoothed label maps to model uncertainties and shape variabilities, which do not conform to any generative model or estimation process, and are therefore suboptimal. In this paper, we propose to learn probabilistic label maps using a generative model on given set of binary label maps. The proposed approach generalizes well on unseen data while simultaneously capturing the variability in the training samples...
April 2016: Proceedings of the IEEE International Symposium on Biomedical Imaging: from Nano to Macro
https://www.readbyqxmd.com/read/28087505/2016-update-of-the-asas-eular-management-recommendations-for-axial-spondyloarthritis
#5
Désirée van der Heijde, Sofia Ramiro, Robert Landewé, Xenofon Baraliakos, Filip Van den Bosch, Alexandre Sepriano, Andrea Regel, Adrian Ciurea, Hanne Dagfinrud, Maxime Dougados, Floris van Gaalen, Pál Géher, Irene van der Horst-Bruinsma, Robert D Inman, Merryn Jongkees, Uta Kiltz, Tore K Kvien, Pedro M Machado, Helena Marzo-Ortega, Anna Molto, Victoria Navarro-Compàn, Salih Ozgocmen, Fernando M Pimentel-Santos, John Reveille, Martin Rudwaleit, Jochen Sieper, Percival Sampaio-Barros, Dieter Wiek, Jürgen Braun
To update and integrate the recommendations for ankylosing spondylitis and the recommendations for the use of tumour necrosis factor inhibitors (TNFi) in axial spondyloarthritis (axSpA) into one set applicable to the full spectrum of patients with axSpA. Following the latest version of the European League Against Rheumatism (EULAR) Standardised Operating Procedures, two systematic literature reviews first collected the evidence regarding all treatment options (pharmacological and non-pharmacological) that were published since 2009...
January 13, 2017: Annals of the Rheumatic Diseases
https://www.readbyqxmd.com/read/28079361/controllable-synthesis-of-smart-multifunctional-nanoscal-metal-organic-framework-for-magnetic-resonance-optical-imaging-and-targeted-drug-delivery
#6
Xuechuan Gao, Manjue Zhai, Weihua Guan, Jingjuan Liu, Zhiliang Liu, Alatangaole Damirin
As a result of their extraordinarily large surfaces and well-defined pores, the design of multifunctional metal-organic framework (MOF) is crucial for drug delivery while has been rarely reported. In this paper, a novel drug delivery system (DDS) based on nanoscale metal-organic framework (MOF) was developed for using in cancer diagnosis and therapy. This MOF based tumour targeting DDS was fabricated by a simple post-synthetic surface modification process. Firstly, magnetic mesoporous nanomaterial Fe-MIL-53-NH2 was devoted for encapsulating the drug and served as a magnetic resonance (MR) contrast agent...
January 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28066844/tight-graph-framelets-for-sparse-diffusion-mri-q-space-representation
#7
Pew-Thian Yap, Bin Dong, Yong Zhang, Dinggang Shen
In diffusion MRI, the outcome of estimation problems can often be improved by taking into account the correlation of diffusion-weighted images scanned with neighboring wavevectors in q-space. For this purpose, we propose in this paper to employ tight wavelet frames constructed on non-flat domains for multi-scale sparse representation of diffusion signals. This representation is well suited for signals sampled regularly or irregularly, such as on a grid or on multiple shells, in q-space. Using spectral graph theory, the frames are constructed based on quasi-affine systems (i...
October 2016: Medical Image Computing and Computer-assisted Intervention: MICCAI ..
https://www.readbyqxmd.com/read/28050692/effect-of-inversion-time-on-the-precision-of-myocardial-late-gadolinium-enhancement-quantification-evaluated-with-synthetic-inversion-recovery-mr-imaging
#8
Akos Varga-Szemes, Rob J van der Geest, U Joseph Schoepf, Bruce S Spottiswoode, Carlo N De Cecco, Giuseppe Muscogiuri, Julian L Wichmann, Stefanie Mangold, Stephen R Fuller, Pal Maurovich-Horvat, Bela Merkely, Sheldon E Litwin, Rozemarijn Vliegenthart, Pal Suranyi
OBJECTIVES: To evaluate the influence of inversion time (TI) on the precision of myocardial late gadolinium enhancement (LGE) quantification using synthetic inversion recovery (IR) imaging in patients with myocardial infarction (MI). METHODS: Fifty-three patients with suspected prior MI underwent 1.5-T cardiac MRI with conventional magnitude (MagIR) and phase-sensitive IR (PSIR) LGE imaging and T1 mapping at 15 min post-contrast. T1-based synthetic MagIR and PSIR images were calculated with a TI ranging from -100 to +150 ms at 5-ms intervals relative to the optimal TI (TI0)...
January 3, 2017: European Radiology
https://www.readbyqxmd.com/read/28048467/su-g-jep2-08-image-guided-radiation-therapy-using-synthetic-cts-in-brain-cancer
#9
R G Price, J Kim, W Zheng, I J Chetty, C Glide-Hurst
PURPOSE: Synthetic-CTs(synCTs) are essential for MR-only treatment planning. However, the performance of synCT for IGRT must be carefully assessed. This work evaluated the accuracy of synCT and synCT-generated DRRs and determined their performance for IGRT in brain cancer radiation therapy. METHODS: MR-SIM and CT-SIM images were acquired of a novel anthropomorphic phantom and a cohort of 12 patients. SynCTs were generated by combining an ultra-short echo time (UTE) sequence with other MRI datasets using voxel-based weighted summation...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047989/tu-ab-bra-03-atlas-based-algorithms-with-local-registration-goodness-weighting-for-mri-driven-electron-density-mapping
#10
R Farjam, N Tyagi, H Veeraraghavan, A Apte, K Zakian, M Hunt, J Deasy
PURPOSE: To develop image-analysis algorithms to synthesize CT with accurate electron densities for MR-only radiotherapy of head & neck (H&N) and pelvis anatomies. METHODS: CT and 3T-MRI (Philips, mDixon sequence) scans were randomly selected from a pool of H&N (n=11) and pelvis (n=12) anatomies to form an atlas. All MRIs were pre-processed to eliminate scanner and patient-induced intensity inhomogeneities and standardize their intensity histograms. CT and MRI for each patient were then co-registered to construct CT-MRI atlases...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047532/th-ef-bra-05-a-method%C3%A3-of-near-real-time-4d-mri-using-volumetric-dynamic-keyhole-vdk-in-the-presence-of-respiratory-motion-for-mr-guided-radiotherapy
#11
B Lewis, S Kim, T Kim
PURPOSE: To develop a novel method that enables 4D MR imaging in near real-time for continuous monitoring of tumor motion in MR-guided radiotherapy. METHODS: This method is mainly based on an idea of expanding dynamic keyhole to full volumetric imaging acquisition. In the VDK approach introduced in this study, a library of peripheral volumetric k-space data is generated in given number of phases (5 and 10 in this study) in advance. For 4D MRI at any given time, only volumetric central k-space data are acquired in real-time and combined with pre-acquired peripheral volumetric k-space data in the library corresponding to the respiratory phase (or amplitude)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047518/su-f-j-165-spectral-characterization-of-tissues-in-high-spectral-and-spatial-resolution-mr-images-in-vitro-implications-for-classification-based-synthetic-ct-algorithm
#12
A Diak, S Shea, M Surucu, S Gros, M Medved, G Karczmar, W Small, J Roeske
PURPOSE: To investigate features of spectral parameters of tissue for use in a synthetic CT algorithm. METHODS: A phantom of fresh beef leg embedded in 1% agarose gel was imaged at 1.5T on a Siemens Aero using HiSS MRI with 1.0mm resolution and 11.1Hz spectral resolution. Post-processing was performed off-line and included labeling of fat and water peaks, and fitting the spectra. All spectra were normalized by the noise within each voxel; thus all parameters are reported in units of signal-to-noise (SNR)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28047055/su-g-jep2-06-dosimetric-and-workflow-evaluation-of-first-commercial-synthetic-ct-software-for-clinical-use-in-pelvis
#13
N Tyagi, J Zhang, L Happersett, M Kadbi, J Mechalakos, J Deasy, M Hunt
PURPOSE: evaluate a commercial synthetic CT (syn-CT) software for use in prostate radiotherapy METHODS: Twenty prostate patients underwent CT and MR simulation scans in treatment position on a 3T Philips scanner. The MR protocol consisted of a T2w turbo spin-echo for soft tissue contrast, a 2D balanced-fast field echo (b-FFE) for fiducial identification, a dual-echo 3D FFE B0 map for distortion analysis and a 3D mDIXON FFE sequence to generate syn-CT. Two echoes are acquired during mDIXON scan, allowing water, fat, and in-phase images to be derived using the frequency shift of the fat and water protons...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046762/su-f-j-162-is-bulky-electron-density-assignment-appropriatefor-mri-only-based-treatment-planning-for-lung-cancer
#14
P Prior, X Chen, C Johnstone, E Gore, X Li
PURPOSE: To assess the appropriateness of bulky electron density assisment for MRI-only treatment planning for lung cancer via comparing dosimetric difference between MRI- and CT-based plans. METHODS: Planning 4DCTs acquired for six representative lung cancer patients were used to generate CT-based IMRT plans. To avoid the effect of anatomic difference between CT and MRI, MRI-based plans were generated using CTs by forcing the relative electron density (rED) of organ specific values from ICRU report 46 and using the mean rED value of the internal target volume (ITV) of the patient for the ITV...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046606/tu-ab-bra-01-abdominal-synthetic-ct-generation-in-support-of-liver-sbrt-dose-calculation
#15
J S Bredfeldt, L Liu, M Feng, Y Cao, J Balter
PURPOSE: To demonstrate and validate a technique for generating MRI-derived synthetic CT volumes (MRCTs) in support of adaptive liver SBRT. METHODS: Under IRB approval, ten hepatocellular carcinoma patients were scanned using a single MR sequence (T1 Dixon-VIBE), yielding inherently-registered water, fat, and T1-weighted images. Air-containing voxels were identified by intensity thresholding. The envelope of the anterior vertebral bodies was segmented from the fat image by fitting a shape model to vertebral body candidate voxels, then using level sets to expand the contour outward...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28046509/su-c-bra-06-automatic-brain-tumor-segmentation-for-stereotactic-radiosurgery-applications
#16
Y Liu, S Stojadinovic, S Jiang, R Timmerman, R Abdulrahman, L Nedzi, X Gu
PURPOSE: Stereotactic radiosurgery (SRS), which delivers a potent dose of highly conformal radiation to the target in a single fraction, requires accurate tumor delineation for treatment planning. We present an automatic segmentation strategy, that synergizes intensity histogram thresholding, super-voxel clustering, and level-set based contour evolving methods to efficiently and accurately delineate SRS brain tumors on contrast-enhance T1-weighted (T1c) Magnetic Resonance Images (MRI)...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28038965/inversion-recovery-ultrashort-echo-time-magnetic-resonance-imaging-a-method-for-simultaneous-direct-detection-of-myelin-and-high-signal-demonstration-of-iron-deposition-in-the-brain-a-feasibility-study
#17
Vipul R Sheth, Shujuan Fan, Qun He, Yajun Ma, Jacopo Annese, Robert Switzer, Jody Corey-Bloom, Graeme M Bydder, Jiang Du
Multiple sclerosis (MS) causes demyelinating lesions in the white matter and increased iron deposition in the subcortical gray matter. Myelin protons have an extremely short T2* (<1ms) and are not directly detected with conventional clinical magnetic resonance (MR) imaging sequences. Iron deposition also reduces T2*, leading to reduced signal on clinical sequences. In this study we tested the hypothesis that the inversion recovery ultrashort echo time (IR-UTE) pulse sequence can directly and simultaneously image myelin and iron deposition using a clinical 3T scanner...
December 28, 2016: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28033653/-metal-organic-frameworks-for-biomedical-applications-in-drug-delivery-and-as-mri-contrast-agents
#18
REVIEW
Mohammad A Chowdhury
The metal-organic-frameworks (MOFs) materials are increasingly gaining attraction to utilise into biomedical applications. MOFs are playing a major role to harnessing dual or multiple modalities in therapeutics and diagnostics. MOFs are mostly devised for particular biomedical application by post-synthetic functionalization or modification using variety of polymers, bio-ligands, and silica coating processes. This articles presents a brief overview of two particular areas of biomedical applications where a broad range of MOFs have been used: 1) variety of drug delivery including intracellular drug delivery systems using the MOFs-based carriers; and, 2) development of MOFs-based contrast agents for magnetic resonance image enhancement...
December 29, 2016: Journal of Biomedical Materials Research. Part A
https://www.readbyqxmd.com/read/28033002/smaragdyrins-and-sapphyrins-analogues
#19
Tamal Chatterjee, A Srinivasan, Mangalampalli Ravikanth, Tavarakere K Chandrashekar
Porphyrins and expanded porphyrins have attracted the attention of chemists for a long time in view of their diverse applications in catalysis; as anion, cation, and neutral substrate receptors; as ligands to coordinate large metal ions; as nonlinear optical materials, MRI contrasting agents, and sensitizers for photodynamic therapy (PDT); and more recently as models for aromaticity (both Hückel and Möbius). A diverse range of synthetic expanded porphyrins containing up to 96π electrons have been reported, and their properties have been exploited for various applications...
December 29, 2016: Chemical Reviews
https://www.readbyqxmd.com/read/28019018/contrast-mechanisms-associated-with-neuromelanin-mri
#20
Paula Trujillo, Paul E Summers, Emanuele Ferrari, Fabio A Zucca, Michela Sturini, Luca T Mainardi, Sergio Cerutti, Alex K Smith, Seth A Smith, Luigi Zecca, Antonella Costa
PURPOSE: To investigate the physical mechanisms associated with the contrast observed in neuromelanin MRI. METHODS: Phantoms having different concentrations of synthetic melanins with different degrees of iron loading were examined on a 3 Tesla scanner using relaxometry and quantitative magnetization transfer (MT). RESULTS: Concentration-dependent T1 and T2 shortening was most pronounced for the melanin pigment when combined with iron. Metal-free melanin had a negligible effect on the magnetization transfer spectra...
December 26, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
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