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MR perfusion

J Wu, S Dehkharghani, F Nahab, J Allen, D Qiu
BACKGROUND AND PURPOSE: Measuring cerebrovascular reactivity with the use of vasodilatory stimuli, such as acetazolamide, is useful for chronic cerebrovascular steno-occlusive disease. The purpose of this study was to evaluate the effects of acetazolamide on the assessment of hemodynamic impairment and functional connectivity by using noninvasive resting-state blood oxygen level-dependent MR imaging. MATERIALS AND METHODS: A 20-minute resting-state blood oxygen level-dependent MR imaging scan was acquired with infusion of acetazolamide starting at 5 minutes after scan initiation...
October 6, 2016: AJNR. American Journal of Neuroradiology
Sven Haller, Greg Zaharchuk, David L Thomas, Karl-Olof Lovblad, Frederik Barkhof, Xavier Golay
Arterial spin labeling (ASL) is a magnetic resonance (MR) imaging technique used to assess cerebral blood flow noninvasively by magnetically labeling inflowing blood. In this article, the main labeling techniques, notably pulsed and pseudocontinuous ASL, as well as emerging clinical applications will be reviewed. In dementia, the pattern of hypoperfusion on ASL images closely matches the established patterns of hypometabolism on fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) images due to the close coupling of perfusion and metabolism in the brain...
November 2016: Radiology
Qian Zhao, Xueqi Chen, Yun Zhou
Alzheimer's disease (AD) is a progressive neurodegenerative disorder, causing changes in memory, thinking, and other dysfunction of brain functions. More and more people are suffering from the disease. Early neuroimaging techniques of AD are needed to develop. This review provides a preliminary summary of the various neuroimaging techniques that have been explored for in vivo imaging of AD. Recent advances in magnetic resonance (MR) techniques, such as functional MR imaging (fMRI) and diffusion MRI, give opportunities to display not only anatomy and atrophy of the medial temporal lobe, but also at microstructural alterations or perfusion disturbance within the AD lesions...
March 2016: Brain Informatics
Mark Doyle, Gerald M Pohost, C Noel Bairey Merz, Leslee J Shaw, George Sopko, William J Rogers, Barry L Sharaf, Carl J Pepine, Diane V Thompson, Geetha Rayarao, Lindsey Tauxe, Sheryl F Kelsey, Robert W W Biederman
BACKGROUND: We introduce an algorithmic approach to optimize diagnostic and prognostic value of gated cardiac single photon emission computed tomography (SPECT) and magnetic resonance (MR) myocardial perfusion imaging (MPI) modalities in women with suspected myocardial ischemia. The novel approach: bio-informatics assessment schema (BIAS) forms a mathematical model utilizing MPI data and cardiac metrics generated by one modality to predict the MPI status of another modality. The model identifies cardiac features that either enhance or mask the image-based evidence of ischemia...
October 2016: Cardiovascular Diagnosis and Therapy
Nolan S Hartkamp, Reinoud P H Bokkers, M J P van Osch, Gert J de Borst, Jeroen Hendrikse
BACKGROUND AND PURPOSE: To assess the effect of unilateral large vessel disease upon the cerebral hemodynamic autoregulatory status in the basal ganglia of patients with steno-occlusive internal carotid artery (ICA) disease. MATERIALS AND METHODS: Twenty-five healthy volunteers and 38 patients with a unilateral symptomatic steno-occlusive ICA lesion and were investigated; 20 with a stenosis >50% and 18 with an occlusion. Cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were assessed with pseudo-continuous arterial spin labeling (ASL) magnetic resonance (MR) imaging before and after administration of acetazolamide...
October 12, 2016: Journal of Neuroradiology. Journal de Neuroradiologie
Lara A Brandão, Mauricio Castillo
Proton magnetic resonance spectroscopy (H-MRS) may be helpful in suggesting tumor histology and tumor grade and may better define tumor extension and the ideal site for biopsy compared with conventional magnetic resonance (MR) imaging. A multifunctional approach with diffusion-weighted imaging, perfusion-weighted imaging, and permeability maps, along with H-MRS, may enhance the accuracy of the diagnosis and characterization of brain tumors and estimation of therapeutic response. Integration of advanced imaging techniques with conventional MR imaging and the clinical history help to improve the accuracy, sensitivity, and specificity in differentiating tumors and nonneoplastic lesions...
November 2016: Magnetic Resonance Imaging Clinics of North America
Brent Griffith, Rajan Jain
Perfusion imaging is a method for assessing the flow of blood occurring at the tissue level and can be accomplished by both CT and MR perfusion techniques. The use of perfusion imaging has increased substantially in the past decade, particularly in neuro-oncologic imaging, where it is has been used for brain tumor grading and directing biopsies or targeted therapy, as well as for the evaluation of treatment response and disease progression. This article discusses the basic principles and techniques of perfusion imaging, as well as its applications in neuro-oncology...
November 2016: Magnetic Resonance Imaging Clinics of North America
Arnav Mehta, Ketan Ghaghada, Srinivasan Mukundan
The first generation of cross-sectional brain imaging using computed tomography (CT), ultrasonography, and eventually MR imaging focused on determining structural or anatomic changes associated with brain disorders. The current state-of-the-art imaging, functional imaging, uses techniques such as CT and MR perfusion that allow determination of physiologic parameters in vivo. In parallel, tissue-based genomic, transcriptomic, and proteomic profiling of brain tumors has created several novel and exciting possibilities for molecular targeting of brain tumors...
November 2016: Magnetic Resonance Imaging Clinics of North America
Jerrold L Boxerman, Mark S Shiroishi, Benjamin M Ellingson, Whitney B Pope
Dynamic susceptibility contrast (DSC) MR imaging, a perfusion-weighted MR imaging technique typically used in neuro-oncologic applications for estimating the relative cerebral blood volume within brain tumors, has demonstrated much potential for determining prognosis, predicting therapeutic response, and assessing early treatment response of gliomas. This review highlights recent developments using DSC-MR imaging and emphasizes the need for technical standardization and validation in prospective studies in order for this technique to become incorporated into standard-of-care imaging for patients with brain tumors...
November 2016: Magnetic Resonance Imaging Clinics of North America
Ursula I Tuor, Min Qiao, Manasi Sule, Melissa Morgunov, Tadeusz Foniok
Stroke is a major cause of disability in adults and children. Recently, we have developed an adult rat model of minor stroke containing a peri-infarct region with a modest T2 increase and mild ischemic damage. We hypothesized that a neonatal minor stroke with mild peri-ischemic changes could also be produced, but with potential ontogenic differences. Using our minor photothrombosis method, we produced a range of severities of ischemic lesions (mini, minor, moderate and severe) within magnetic resonance imaging (MRI) slices of adult and neonatal rats...
October 12, 2016: NMR in Biomedicine
Christopher J François, Mark L Schiebler
Multimodality, noninvasive imaging is increasingly used in the identification and management of pulmonary hypertension (PH). Chest radiography, ventilation-perfusion scintigraphy, and Doppler echocardiography are frequently the initial studies used to evaluate patients suspected of having PH. However, their ability to evaluate the right ventricle (RV) and pulmonary vasculature is limited. Computed tomography (CT) and magnetic resonance (MR) imaging are increasingly used to identify causes of PH and assess the effect of PH on RV function...
November 2016: Radiologic Clinics of North America
Neil P Jerome, Jessica K R Boult, Matthew R Orton, James d'Arcy, David J Collins, Martin O Leach, Dow-Mu Koh, Simon P Robinson
BACKGROUND: To investigate the combined use of intravoxel incoherent motion (IVIM) diffusion-weighted (DW) and blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) to assess rat renal function using a 1.5T clinical platform. METHODS: Multiple b-value DW and BOLD MR images were acquired from adult rats using a parallel clinical coil arrangement, enabling quantitation of the apparent diffusion coefficient (ADC), IVIM-derived diffusion coefficient (D), pseudodiffusion coefficient (D*) and perfusion fraction (f), and the transverse relaxation time T2*, for whole kidney, renal cortex, and medulla...
October 3, 2016: BMC Nephrology
Marc C Mabray, Soonmee Cha
This article presents a summary of advanced MR imaging techniques and their use in the evaluation of patients with brain tumors. It reviews diffusion-weighted imaging, diffusion-tensor imaging, T2* susceptibility-sensitive imaging, MR spectroscopy, MR perfusion, and functional MR imaging, and discusses their current roles in the evaluation of patients with brain tumors.
November 2016: Neuroimaging Clinics of North America
Ramon Francisco Barajas, Soonmee Cha
Metastatic cancer to the central nervous system is primarily deposited by hematogenous spread in various anatomically distinct regions: calvarial, pachymeningeal, leptomeningeal, and brain parenchyma. A patient's overall clinical status and the information needed to make treatment decisions are the primary considerations in initial imaging modality selection. Contrast-enhanced MR imaging is the preferred imaging modality. Morphologic MR imaging is limited to delineating anatomic deraignment of tissues. Dynamic susceptibility contrast-enhanced perfusion and diffusion-weighted physiology-based MR imaging sequences have been developed that complement morphologic MR imaging by providing additional diagnostic information...
November 2016: Neuroimaging Clinics of North America
Lara A Brandão, Mauricio Castillo
Primary central nervous system lymphomas are aggressive, high-cell-density tumors. There is recent increase in their incidence in immunocompetent patients. Knowledge of imaging findings on computed tomography and conventional MR imaging is important to suggest the diagnosis. Moreover, information obtained from advanced MR imaging techniques, such as diffusion-weighted imaging, diffusion tensor imaging, MR spectroscopy, perfusion-weighted imaging, and dynamic contrast-enhanced studies, increases diagnostic confidence and helps distinguish them from other aggressive intracranial tumors...
November 2016: Neuroimaging Clinics of North America
Kai Jiang, Christopher M Ferguson, Behzad Ebrahimi, Hui Tang, Timothy L Kline, Tyson A Burningham, Prassana K Mishra, Joseph P Grande, Slobodan I Macura, Lilach O Lerman
Purpose To test the utility of magnetization transfer imaging in detecting and monitoring the progression of renal fibrosis in mice with unilateral renal artery stenosis. Materials and Methods This prospective study was approved by the Institutional Animal Care and Use Committee. Renal artery stenosis surgery (n = 10) or sham surgery (n = 5) was performed, and the stenotic and contralateral kidneys were studied longitudinally in vivo at baseline and 2, 4, and 6 weeks after surgery. After a 16.4-T magnetic resonance imaging examination, magnetization transfer ratio was measured as an index of fibrosis (guided by parameters selected in preliminary phantom studies)...
October 3, 2016: Radiology
Eli Eikefjord, Erling Andersen, Erlend Hodneland, Erik A Hanson, Steven Sourbron, Einar Svarstad, Arvid Lundervold, Jarle T Rørvik
BACKGROUND: High repeatability, accuracy, and precision for renal function measurements need to be achieved to establish renal dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) as a clinically useful diagnostic tool. PURPOSE: To investigate the repeatability, accuracy, and precision of DCE-MRI measured renal perfusion and glomerular filtration rate (GFR) using iohexol-GFR as the reference method. MATERIAL AND METHODS: Twenty healthy non-smoking volunteers underwent repeated DCE-MRI and an iohexol-GFR within a period of 10 days...
September 30, 2016: Acta Radiologica
Kasper Wigh Lipsø, Esben Søvsø Szocska Hansen, Rasmus Stilling Tougaard, Christoffer Laustsen, Jan Henrik Ardenkjaer-Larsen
PURPOSE: To study hyperpolarized water as an angiography and perfusion tracer in a large animal model. METHODS: Protons dissolved in deuterium oxide (D2 O) were hyperpolarized in a SPINlab dissolution dynamic nuclear polarization (dDNP) polarizer and subsequently investigated in vivo in a pig model at 3 Tesla (T). Approximately 15 mL of hyperpolarized water was injected in the renal artery by hand over 4-5 s. RESULTS: A liquid state polarization of 5...
September 30, 2016: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Savannah C Partridge, Noam Nissan, Habib Rahbar, Averi E Kitsch, Eric E Sigmund
: Diffusion-weighted MRI (DWI) holds potential to improve the detection and biological characterization of breast cancer. DWI is increasingly being incorporated into breast MRI protocols to address some of the shortcomings of routine clinical breast MRI. Potential benefits include improved differentiation of benign and malignant breast lesions, assessment and prediction of therapeutic efficacy, and noncontrast detection of breast cancer. The breast presents a unique imaging environment with significant physiologic and inter-subject variations, as well as specific challenges to achieving reliable high quality diffusion-weighted MR images...
September 30, 2016: Journal of Magnetic Resonance Imaging: JMRI
Meng Lin, Xiaoduo Yu, Yan Chen, Han Ouyang, Bing Wu, Dandan Zheng, Chunwu Zhou
OBJECTIVES: To investigate the potential of various metrics derived from mono-exponential model (MEM), bi-exponential model (BEM) and stretched exponential model (SEM)-based diffusion-weighted imaging (DWI) in diagnosing and differentiating the pathological subtypes and grades of uterine cervical carcinoma. METHODS: 71 newly diagnosed patients with cervical carcinoma (50 cases of squamous cell carcinoma [SCC] and 21 cases of adenocarcinoma [AC]) and 32 healthy volunteers received DWI with multiple b values...
September 27, 2016: European Radiology
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