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MR perfusion

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https://www.readbyqxmd.com/read/28330686/imaging-of-acute-and-chronic-thromboembolic-disease-state-of-the-art
#1
REVIEW
A Ruggiero, N J Screaton
Acute pulmonary embolism (PE) is a life-threatening condition that requires prompt diagnosis and treatment. Recent advances in imaging allow acute and rapid recognition even by the non-specialist radiologist. Most acute emboli resolve on anticoagulation without sequelae; however, some emboli fail to fully resolve becoming endothelialised with the development of chronic thromboembolic disease (CTED). Increased pulmonary vascular resistance arising from CTED may lead to chronic thromboembolic pulmonary hypertension (CTEPH) a debilitating disease affecting up to 5% of survivors of acute PE...
March 19, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/28306418/an-mrs-and-pet-guided-biopsy-tool-for-intraoperative-neuronavigational-systems
#2
Matthew Grech-Sollars, Babar Vaqas, Gerard Thompson, Tara Barwick, Lesley Honeyfield, Kevin O'Neill, Adam D Waldman
OBJECTIVE Glioma heterogeneity and the limitations of conventional structural MRI for identifying aggressive tumor components can limit the reliability of stereotactic biopsy and, hence, tumor characterization, which is a hurdle for developing and selecting effective treatment strategies. In vivo MR spectroscopy (MRS) and PET enable noninvasive imaging of cellular metabolism relevant to proliferation and can detect regions of more highly active tumor. Here, the authors integrated presurgical PET and MRS with intraoperative neuronavigation to guide surgical biopsy and tumor sampling of brain gliomas with the aim of improving intraoperative tumor-tissue characterization and imaging biomarker validation...
March 17, 2017: Journal of Neurosurgery
https://www.readbyqxmd.com/read/28301491/the-performance-of-mr-perfusion-weighted-imaging-for-the-differentiation-of-high-grade-glioma-from-primary-central-nervous-system-lymphoma-a-systematic-review-and-meta-analysis
#3
Weilin Xu, Qun Wang, Anwen Shao, Bainan Xu, Jianmin Zhang
It is always a great challenge to distinguish high-grade glioma (HGG) from primary central nervous system lymphoma (PCNSL). We conducted a meta-analysis to assess the performance of MR perfusion-weighted imaging (PWI) in differentiating HGG from PCNSL. The heterogeneity and threshold effect were evaluated, and the sensitivity (SEN), specificity (SPE) and areas under summary receiver operating characteristic curve (SROC) were calculated. Fourteen studies with a total of 598 participants were included in this meta-analysis...
2017: PloS One
https://www.readbyqxmd.com/read/28295552/high-resolution-dynamic-oxygen-17-mr-imaging-of-mouse-brain-with-golden-ratio-based-radial-sampling-and-k-space-weighted-image-reconstruction
#4
Yuchi Liu, Yifan Zhang, Chunying Wu, Junqing Zhu, Charlie Wang, Nicholas Tomko, Mikhail D Linetsky, Robert G Salomon, Ciro Ramos-Estebanez, Yanming Wang, Xin Yu
PURPOSE: The current study aimed to develop a three-dimensional (3D) dynamic oxygen-17 ((17) O) MR imaging method with high temporal and spatial resolution to delineate the kinetics of (17) O water uptake and washout in the brains of mice with glioblastoma (GBM). METHODS: A 3D imaging method with a stack-of-stars golden-ratio-based radial sampling scheme was employed to acquire (17) O signal in vivo. A k-space-weighted image reconstruction method was used to improve the temporal resolution while preserving spatial resolution...
March 13, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28291957/effect-of-intranasally-administered-insulin-on-cerebral-blood-flow-and-perfusion-a-randomized-experiment-in-young-and-older-adults
#5
Abimbola A Akintola, Anna M van Opstal, Rudi G Westendorp, Iris Postmus, Jeroen van der Grond, Diana van Heemst
Insulin, a vasoactive modulator regulating peripheral and cerebral blood flow, has been consistently linked to aging and longevity. In this proof of principle study, using a randomized, double-blinded, placebo-controlled crossover design, we explored the effects of intranasally administered insulin (40IU) on cerebral blood flow (CBF) and perfusion in older (60-69 years, n=11) and younger (20-26 years, n=8) adults. Changes in CBF through the major cerebropetal arteries were assessed via phase contrast MR-angiography, and regional cortical tissue perfusion via pseudo-continuous arterial spin labelling...
March 14, 2017: Aging
https://www.readbyqxmd.com/read/28277554/morphological-changes-of-anterior-cerebral-artery-aca-in-hydrocephalic-pediatric-patients
#6
Sait Ozturk, Erdogan Ayan, Metin Kaplan
OBJECTIVE: The morphology of anterior cerebral artery (ACA) in patients with hydrocephalus (HCP) was analyzed, and its importance was discussed in maintaining cerebral perfusion. MATERIALS & METHODS: A total of 84 cases in 2 groups between 0 and 3 months, followed-up at Firat Universitesi Hastanesi, Beyin Cerrahisi Klinigi, Elazig, Turkiye due to in 2010-2013, were enrolled. Two groups were created for the study. Group 1; patients with HCP and Group 2; as control group without HCP...
2017: Iranian Journal of Child Neurology
https://www.readbyqxmd.com/read/28277461/imaging-brain-collaterals-quantification-scoring-and-potential-significance
#7
Scott B Raymond, Pamela W Schaefer
Leptomeningeal collaterals provide the primary source of perfusion to ischemic brain tissue following the onset of acute ischemic stroke and are becoming an important imaging biomarker for stroke therapy triage. Collateral circulation is predictive of infarct growth, end infarct volume, and response to endovascular therapy. The strength of the collateral circulation varies among patients and is partially dependent on genetic and modifiable risk factors. Collateral circulation may be assessed by standard angiographic techniques, including digital subtraction angiography, computed tomography and magnetic resonance (MR) angiography, as well as a growing array of advanced MR techniques including arterial spin labeling and dynamic MR angiography...
March 8, 2017: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/28277459/diffusion-and-perfusion-mr-imaging-in-acute-stroke-clinical-utility-and-potential-limitations-for-treatment-selection
#8
Mathew Bateman, Lee-Anne Slater, Thabele Leslie-Mazwi, Claus Z Simonsen, Stephen Stuckey, Ronil V Chandra
Magnetic resonance (MR) diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) offer unique insight into acute ischemic stroke pathophysiology. These techniques may offer the ability to apply pathophysiology to accurately individualize acute stroke reperfusion treatment, including extending the opportunity of reperfusion treatment to well beyond the current time-based treatment windows.This review examines the use of DWI and PWI in the major stroke trials, their current clinical utility, and potential limitations for reperfusion treatment selection...
March 8, 2017: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/28277456/resting-state-bold-mri-for-perfusion-and-ischemia
#9
Hannes Kroll, Greg Zaharchuk, Thomas Christen, Jeremy J Heit, Michael Iv
Advanced imaging techniques including computed tomography (CT) angiography, CT perfusion, magnetic resonance (MR) angiography, MR with diffusion- and perfusion-weighted imaging, and, more recently, resting-state BOLD (Blood Oxygen Level Dependent) functional MRI (rs-fMRI) are increasingly used to evaluate patients with acute ischemic stroke. Advanced imaging allows for identification of patients with ischemic stroke and determination of the size of infarcted and potentially salvageable tissue, all of which yield crucial information for proper stroke management...
March 8, 2017: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/28275560/liver-intravoxel-incoherent-motion-ivim-magnetic-resonance-imaging-a-comprehensive-review-of-published-data-on-normal-values-and-applications-for-fibrosis-and-tumor-evaluation
#10
REVIEW
Yáo T Li, Jean-Pierre Cercueil, Jing Yuan, Weitian Chen, Romaric Loffroy, Yì Xiáng J Wáng
A comprehensive literature review was performed on liver intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) technique and its applications. Heterogeneous data have been reported. IVIM parameters are magnetic field strength dependent to a mild extent. A lower Dslow (D) value at 3 T than at 1.5 T and higher perfusion fraction (PF) value at 3 T than at 1.5 T were noted. An increased number of b values are associated with increased IVIM parameter measurement accuracy. With the current status of art, IVIM technique is not yet capable of detecting early stage liver fibrosis and diagnosing liver fibrosis grades, nor can it differentiate liver tumors...
February 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28268545/fast-analytical-spectral-filtering-methods-for-magnetic-resonance-perfusion-quantification
#11
Kasireddy V Reddy, Abhishek Mitra, Phaneendra K Yalavarthy
The deconvolution in the perfusion weighted imaging (PWI) plays an important role in quantifying the MR perfusion parameters. The PWI application to stroke and brain tumor studies has become a standard clinical practice. The standard approach for this deconvolution is oscillatory-limited singular value decomposition (oSVD) and frequency domain deconvolution (FDD). The FDD is widely recognized as the fastest approach currently available for deconvolution of MR perfusion data. In this work, two fast deconvolution methods (namely analytical fourier filtering and analytical showalter spectral filtering) are proposed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28265697/intravoxel-incoherent-motion-diffusion-weighted-magnetic-resonance-imaging-of-focal-vertebral-bone-marrow-lesions-initial-experience-of-the-differentiation-of-nodular-hyperplastic-hematopoietic-bone-marrow-from-malignant-lesions
#12
Sunghoon Park, Kyu-Sung Kwack, Nam-Su Chung, Jinwoo Hwang, Hyun Young Lee, Jae Ho Kim
OBJECTIVE: To evaluate the ability of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (MRI) parameters to differentiate nodular hyperplastic hematopoietic bone marrow (HHBM) from malignant vertebral bone marrow lesions (VBMLs). MATERIALS AND METHODS: A total of 33 patients with 58 VBMLs, including 9 nodular HHBM lesions, 39 bone metastases, and 10 myelomas, were retrospectively assessed. All diagnoses were confirmed either pathologically or via image assessment...
March 6, 2017: Skeletal Radiology
https://www.readbyqxmd.com/read/28263927/the-ivim-signal-in-the-healthy-cerebral-gray-matter-a-play-of-spherical-and-non-spherical-components
#13
Tim Finkenstaedt, Markus Klarhoefer, Christian Eberhardt, Anton S Becker, Gustav Andreisek, Andreas Boss, Cristina Rossi
The intra-voxel incoherent motion (IVIM) model assumes that blood flowing in isotropically distributed capillary segments induces a phase dispersion of the MR signal, which increases the signal attenuation in diffusion-weighted images. However, in most tissue types the capillary network has an anisotropic micro-architecture. In this study, we investigated the possibility to indirectly infer the anisotropy of the capillary network in the healthy cerebral gray matter by evaluating the dependence of the IVIM signal from the direction of the diffusion-encoding...
March 3, 2017: NeuroImage
https://www.readbyqxmd.com/read/28256923/ultrasound-guided-high-intensity-focused-ultrasound-combined-with-gonadotropin-releasing-hormone-analogue-gnrha-ablating-uterine-leiomyoma-with-homogeneous-hyperintensity-on-t2-weighted-mr-imaging
#14
Shenghua Yang, Fanjing Kong, Ruijie Hou, Fengmin Rong, Nana Ma, Shaoping Li, Jun Yang
OBJECTIVES: The study aimed to evaluate the safety and efficiency of Ultrasound guided high-intensity focused ultrasound (USgHIFU) combined with gonadotropin releasing hormone analogue (GnRHa) ablating symptomatic uterine leiomyoma with homogeneous hyperintensity on T2-weighted MR imaging prospectively. METHODS: A total of 34 patients with 42 symptomatic uterine leiomyomas with homogeneous hyperintensity on T2-weighted MR imaging were enrolled in our study. The patient who had multiple uterine leiomyomas, only one dominant leiomyoma was treated...
March 3, 2017: British Journal of Radiology
https://www.readbyqxmd.com/read/28255464/impairments-in-brain-perfusion-metabolites-functional-connectivity-and-cognition-in-severe-asymptomatic-carotid-stenosis-patients-an-integrated-mri-study
#15
Tao Wang, Feng Xiao, Guangyao Wu, Jian Fang, Zhenmeng Sun, Hongliang Feng, Junjian Zhang, Haibo Xu
Carotid artery stenosis without transient ischemic attack (TIA) or stroke is considered as "asymptomatic." However, recent studies have demonstrated that these asymptomatic carotid artery stenosis (aCAS) patients had cognitive impairment in tests of executive function, psychomotor speed, and memory, indicating that "asymptomatic" carotid stenosis may not be truly asymptomatic. In this study, when 19 aCAS patients compared with 24 healthy controls, aCAS patients showed significantly poorer performance on global cognition, memory, and executive function...
2017: Neural Plasticity
https://www.readbyqxmd.com/read/28254864/arterial-co2-as-a-potent-coronary-vasodilator-a-preclinical-pet-mr-validation-study-with-implications-for-cardiac-stress-testing
#16
Hsin-Jung Yang, Damini Dey, Jane Sykes, Michael Klein, John Butler, Michael Kovacs, Olivia Sobczyk, Behzad Sharif, Xiaoming Bi, Avinash Kali, Ivan Cokic, Richard Tang, Roya Yumul, Antonio Conte, Sotirios Tsaftaris, Mourad Tighiouart, Debiao Li, Piotr J Slomka, Daniel Berman, Frank Prato, Joseph Fisher, Rohan Dharmakumar
Myocardial blood flow (MBF) is the critical determinant of cardiac function. However, its response to increases in partial pressure of arterial CO2 (PaCO2), particularly with respect to adenosine, is not well characterized due to challenges in blood gas control and limited availability of validated approaches to ascertain MBF in vivo. By prospectively and independently controlling PaCO2 and combining it with (13)N-ammonia Positron Emission Tomography (PET) measurements, we investigated whether a physiologically tolerable hypercapnic stimulus (~25-mmHg increase in PaCO2) can increase MBF to that observed with adenosine in three groups of canines: (i) without coronary stenosis; (ii) subjected to non-flow limiting coronary stenosis; and (iii) following pre-administration of caffeine...
March 2, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28240563/multiparametric-mr-imaging-of-diffusion-and-perfusion-in-contrast-enhancing-and-nonenhancing-components-in-patients-with-glioblastoma
#17
Natalie R Boonzaier, Timothy J Larkin, Tomasz Matys, Anouk van der Hoorn, Jiun-Lin Yan, Stephen J Price
Purpose To determine whether regions of low apparent diffusion coefficient (ADC) with high relative cerebral blood volume (rCBV) represented elevated choline (Cho)-to-N-acetylaspartate (NAA) ratio (hereafter, Cho/NAA ratio) and whether their volumes correlated with progression-free survival (PFS) and overall survival (OS) in patients with glioblastoma (GBM). Materials and Methods This retrospective analysis was approved by the local research ethics committee. Volumetric analysis of imaging data from 43 patients with histologically confirmed GBM was performed...
February 27, 2017: Radiology
https://www.readbyqxmd.com/read/28237004/nuclear-medicine-in-pediatric-cardiology
#18
REVIEW
Ornella Milanesi, Giovanni Stellin, Pietro Zucchetta
Accurate cardiovascular imaging is essential for the successful management of patients with congenital heart disease (CHD). Echocardiography and angiography have been for long time the most important imaging modalities in pediatric cardiology, but nuclear medicine has contributed in many situations to the comprehension of physiological consequences of CHD, quantifying pulmonary blood flow symmetry or right-to-left shunting. In recent times, remarkable improvements in imaging equipments, particularly in multidetector computed tomography and magnetic resonance imaging, have led to the progressive integration of high resolution modalities in the clinical workup of children affected by CHD, reducing the role of diagnostic angiography...
March 2017: Seminars in Nuclear Medicine
https://www.readbyqxmd.com/read/28226722/fast-analytical-spectral-filtering-methods-for-magnetic-resonance-perfusion-quantification
#19
Kasireddy V Reddy, Abhishek Mitra, Phaneendra K Yalavarthy, Kasireddy V Reddy, Abhishek Mitra, Phaneendra K Yalavarthy, Abhishek Mitra, Kasireddy V Reddy, Phaneendra K Yalavarthy
The deconvolution in the perfusion weighted imaging (PWI) plays an important role in quantifying the MR perfusion parameters. The PWI application to stroke and brain tumor studies has become a standard clinical practice. The standard approach for this deconvolution is oscillatory-limited singular value decomposition (oSVD) and frequency domain deconvolution (FDD). The FDD is widely recognized as the fastest approach currently available for deconvolution of MR perfusion data. In this work, two fast deconvolution methods (namely analytical fourier filtering and analytical showalter spectral filtering) are proposed...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28225064/intravoxel-incoherent-motion-diffusion-weighted-mr-imaging-in-assessing-and-characterizing-solitary-pulmonary-lesions
#20
Qi Wan, Ying-Shi Deng, Jia-Xuan Zhou, Yu-Dong Yu, Ying-Ying Bao, Qiang Lei, Hou-Jin Chen, Ya-Hui Peng, Ying-Jie Mei, Qing-Si Zeng, Xin-Chun Li
This study aimed to investigate the potential of intravoxel incoherent motion (IVIM) diffusion-weighted MR imaging in assessing solitary pulmonary lesions (SPLs). Sixty-two patients with pathologically confirmed SPLs, including 51 and 11 cases of malignant and benign lesions, respectively, were assessed. Diffusion weighted imaging (DWI) with 13 b values was used to derive apparent diffusion coefficient (ADC) and IVIM parameters, including true diffusion coefficient (D), pseudo-diffusion coefficient (D*), and perfusion fraction (f)...
February 22, 2017: Scientific Reports
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