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Brain perfusion imaging

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https://www.readbyqxmd.com/read/28317276/important-considerations-in-lesion-symptom-mapping-illustrations-from-studies-of-word-comprehension
#1
Hinna Shahid, Rajani Sebastian, Tatiana T Schnur, Taylor Hanayik, Amy Wright, Donna C Tippett, Julius Fridriksson, Chris Rorden, Argye E Hillis
Lesion-symptom mapping is an important method of identifying networks of brain regions critical for functions. However, results might be influenced substantially by the imaging modality and timing of assessment. We tested the hypothesis that brain regions found to be associated with acute language deficits depend on (1) timing of behavioral measurement, (2) imaging sequences utilized to define the "lesion" (structural abnormality only or structural plus perfusion abnormality), and (3) power of the study. We studied 191 individuals with acute left hemisphere stroke with MRI and language testing to identify areas critical for spoken word comprehension...
March 20, 2017: Human Brain Mapping
https://www.readbyqxmd.com/read/28314624/cerebral-white-matter-hypoperfusion-increases-with-small-vessel-disease-burden-data-from-the-third-international-stroke-trial
#2
Francesco Arba, Grant Mair, Trevor Carpenter, Eleni Sakka, Peter A G Sandercock, Richard I Lindley, Domenico Inzitari, Joanna M Wardlaw
BACKGROUND: Leukoaraiosis is associated with impaired cerebral perfusion, but the effect of individual and combined small-vessel disease (SVD) features on white matter perfusion is unclear. METHODS: We studied patients recruited with perfusion imaging in the Third International Stroke Trial. We rated individual SVD features (leukoaraiosis, lacunes) and brain atrophy on baseline plain computed tomography or magnetic resonance imaging. Separately, we assessed white matter at the level of the lateral ventricles in the cerebral hemisphere contralateral to the stroke for visible areas of hypoperfusion (present or absent) on 4 time-based perfusion imaging parameters...
March 14, 2017: Journal of Stroke and Cerebrovascular Diseases: the Official Journal of National Stroke Association
https://www.readbyqxmd.com/read/28306548/repeated-diffusion-mri-reveals-earliest-time-point-for-stratification-of-radiotherapy-response-in-brain-metastases
#3
Faisal Mahmood, Helle H Johannesen, Poul Geertsen, Rasmus H Hansen
An imaging biomarker for early prediction of treatment response potentially provides a non-invasive tool for better prognostics and individualized management of the disease. Radiotherapy (RT) response is generally related to changes in gross tumor volume manifesting months later. In this prospective study we investigated the apparent diffusion coefficient (ADC), perfusion fraction and pseudo diffusion coefficient derived from diffusion weighted MRI as potential early biomarkers for radiotherapy response of brain metastases...
March 17, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28306418/an-mrs-and-pet-guided-biopsy-tool-for-intraoperative-neuronavigational-systems
#4
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/28298042/the-effect-of-cranioplasty-following-decompressive-craniectomy-on-cerebral-blood-perfusion-neurological-and-cognitive-outcome
#5
Adnan Hussain Shahid, Manju Mohanty, Navneet Singla, Bhagwant Rai Mittal, Sunil Kumar Gupta
OBJECTIVE Decompressive craniectomy is an established therapy for refractory intracranial hypertension. Cranioplasty following decompressive craniectomy not only provides protection to the brain along with cosmetic benefits, but also enhances rehabilitation with meaningful functional recovery of potentially reversible cortical and subcortical damaged areas of the affected as well as the contralateral hemisphere. The aim of the study was to assess neurological and cognitive outcome as well as cerebral blood flow after cranioplasty...
March 3, 2017: Journal of Neurosurgery
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
#6
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/28292870/regional-comparison-of-multiphase-computed-tomographic-angiography-and-computed-tomographic-perfusion-for-prediction-of-tissue-fate-in-ischemic-stroke
#7
Christopher D d'Esterre, Anurag Trivedi, Pooneh Pordeli, Mari Boesen, Shivanand Patil, Seong Hwan Ahn, Mohamed Najm, Enrico Fainardi, Jai Jai Shiva Shankar, Marta Rubiera, Mohammed A Almekhlafi, Jennifer Mandzia, Alexander V Khaw, Philip Barber, Shelagh Coutts, Michael D Hill, Andrew M Demchuk, Tolulope Sajobi, Nils D Forkert, Mayank Goyal, Ting-Yim Lee, Bijoy K Menon
BACKGROUND AND PURPOSE: Within different brain regions, we determine the comparative value of multiphase computed tomographic angiography (mCTA) and computed tomographic perfusion (CTP) in predicting follow-up infarction. METHODS: Patients with M1-middle cerebral artery occlusions were prospectively included in this multicenter study. Regional analysis was performed for each patient within Alberta Stroke Program Early CT Score regions M2 to M6. Regional pial vessel filling was assessed on mCTA in 3 ways: (1) Washout of contrast within pial vessels; (2) Extent of maximal pial vessel enhancement compared with contralateral hemisphere; (3) Delay in maximal pial vessel enhancement compared with contralateral hemisphere...
March 14, 2017: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/28286871/semiautomated-workflow-for-clinically-streamlined-glioma-parametric-response-mapping
#8
Lauren Keith, Brian D Ross, Craig J Galbán, Gary D Luker, Stefanie Galbán, Binsheng Zhao, Xiaotao Guo, Thomas L Chenevert, Benjamin A Hoff
Management of glioblastoma multiforme remains a challenging problem despite recent advances in targeted therapies. Timely assessment of therapeutic agents is hindered by the lack of standard quantitative imaging protocols for determining targeted response. Clinical response assessment for brain tumors is determined by volumetric changes assessed at 10 weeks post-treatment initiation. Further, current clinical criteria fail to use advanced quantitative imaging approaches, such as diffusion and perfusion magnetic resonance imaging...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28283606/predictive-value-of-rapid-assessed-perfusion-thresholds-on-final-infarct-volume-in-swift-prime-solitaire-with-the-intention-for-thrombectomy-as-primary-endovascular-treatment
#9
Maxim Mokin, Elad I Levy, Jeffrey L Saver, Adnan H Siddiqui, Mayank Goyal, Alain Bonafé, Christophe Cognard, Reza Jahan, Gregory W Albers
BACKGROUND AND PURPOSE: Computed tomography perfusion imaging can estimate the size of the ischemic core, which can be used for the selection of patients for endovascular therapy. The relative cerebral blood volume (rCBV) and relative cerebral blood flow (rCBF) thresholds chosen to identify ischemic core influence the accuracy of prediction. We aimed to analyze the accuracy of various rCBV and rCBF thresholds for predicting the 27-hour infarct volume using RAPID automated analysis software from the SWIFT PRIME trial (Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment) data...
March 10, 2017: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/28277465/understanding-the-neurophysiology-and-quantification-of-brain-perfusion
#10
Elizabeth Tong, Leo Sugrue, Max Wintermark
Newer neuroimaging technology has moved beyond pure anatomical imaging and ventured into functional and physiological imaging. Perfusion magnetic resonance imaging (PWI), which depicts hemodynamic conditions of the brain at the microvascular level, has an increasingly important role in clinical central nervous system applications. This review provides an overview of the established role of PWI in brain tumor and cerebrovascular imaging, as well as some emerging applications in neuroimaging. PWI allows better characterization of brain tumors, grading, and monitoring...
March 8, 2017: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/28277461/imaging-brain-collaterals-quantification-scoring-and-potential-significance
#11
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/28277457/advanced-mri-measures-of-cerebral-perfusion-and-their-clinical-applications
#12
Bryan Lanzman, Jeremy J Heit
Cerebral blood flow measurement by magnetic resonance imaging perfusion (MRP) techniques is broadly applied to patients with acute ischemic stroke, vasospasm following aneurysmal subarachnoid hemorrhage, chronic arterial steno-occlusive disease, cervical atherosclerotic disease, and primary brain neoplasms. MRP may be performed using an exogenous tracer, most commonly gadolinium-based intravenous contrast, or an endogenous tracer, such as arterial spin labeling (ASL) or intravoxel incoherent motion (IVIM). Here, we review the technical basis of commonly performed MRP techniques, the interpretation of MRP imaging maps, and how MRP provides valuable clinical information in the triage of patients with cerebral disease...
March 8, 2017: Topics in Magnetic Resonance Imaging: TMRI
https://www.readbyqxmd.com/read/28277445/thrombolytic-therapy-in-wake-up-stroke-patients
#13
Gretchen M Stern, Nicholas Van Hise, Lindsay M Urben, Matthew J Korobey, Jamie M Pitlick, Andrew J Crannage
OBJECTIVE: The aim of the study is to review existing and ongoing trial data on wake-up stroke (WUS) patients for thrombolytic therapy. METHODS: A literature search was conducted in PubMed (conception-October 2016) using the terms wake-up stroke, acute ischemic stroke, wake-up thrombolysis, computed tomography imaging in wake-up stroke, and magnetic resonance imaging in wake-up stroke. Ongoing trials were found using the ClinicalTrials.gov website. RESULTS: The search yielded 61 articles in PubMed and 7 ongoing trials...
March 9, 2017: Clinical Neuropharmacology
https://www.readbyqxmd.com/read/28275197/relationship-between-changes-in-the-temporal-dynamics-of-the-blood-oxygen-level-dependent-signal-and-hypoperfusion-in-acute-ischemic-stroke
#14
Ahmed A Khalil, Ann-Christin Ostwaldt, Till Nierhaus, Ramanan Ganeshan, Heinrich J Audebert, Kersten Villringer, Arno Villringer, Jochen B Fiebach
BACKGROUND AND PURPOSE: Changes in the blood-oxygen-level-dependent (BOLD) signal provide a noninvasive measure of blood flow, but a detailed comparison with established perfusion parameters in acute stroke is lacking. We investigated the relationship between BOLD signal temporal delay and dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI) in stroke patients. METHODS: In 30 patients with acute (<24 hours) ischemic stroke, we performed Pearson correlation and multiple linear regression between DSC-MRI parameters (time to maximum [Tmax], mean transit time, cerebral blood flow, and cerebral blood volume) and BOLD-based parameters (BOLD delay and coefficient of BOLD variation)...
March 8, 2017: Stroke; a Journal of Cerebral Circulation
https://www.readbyqxmd.com/read/28273920/white-matter-and-gray-matter-segmentation-in-4d-computed-tomography
#15
Rashindra Manniesing, Marcel T H Oei, Luuk J Oostveen, Jaime Melendez, Ewoud J Smit, Bram Platel, Clara I Sánchez, Frederick J A Meijer, Mathias Prokop, Bram van Ginneken
Modern Computed Tomography (CT) scanners are capable of acquiring contrast dynamics of the whole brain, adding functional to anatomical information. Soft tissue segmentation is important for subsequent applications such as tissue dependent perfusion analysis and automated detection and quantification of cerebral pathology. In this work a method is presented to automatically segment white matter (WM) and gray matter (GM) in contrast- enhanced 4D CT images of the brain. The method starts with intracranial segmentation via atlas registration, followed by a refinement using a geodesic active contour with dominating advection term steered by image gradient information, from a 3D temporal average image optimally weighted according to the exposures of the individual time points of the 4D CT acquisition...
December 2017: Scientific Reports
https://www.readbyqxmd.com/read/28270324/-imaging-methods-used-in-the-differential-diagnosis-between-brain-tumour-relapse-and-radiation-necrosis-after-stereotactic-radiosurgery-of-brain-metastases-literature-review
#16
I Menoux, J-P Armspach, G Noël, D Antoni
After stereotactic radiosurgery for a cerebral metastasis, one of the dreaded toxicities is radionecrosis. In the follow-up of these patients, it is impossible to distinguish radiation necrosis from tumour relapse either clinically or with MRI. In current practice, many imaging methods are designed such as special sequences of MRI (dynamic susceptibility contrast perfusion and susceptibility-weighted imaging, diffusion), proton magnetic resonance spectroscopy, positron emission tomography, or more seldom 201-thallium single-photon emission computerized tomography...
December 2016: Cancer Radiothérapie: Journal de la Société Française de Radiothérapie Oncologique
https://www.readbyqxmd.com/read/28269159/learning-to-distinguish-cerebral-vasculature-data-from-mechanical-chatter-in-india-ink-images-acquired-using-knife-edge-scanning-microscopy
#17
Michael R Nowak, Yoonsuck Choe
We introduce a simple, yet effective, procedure for accurate classification of connected components embedded in biological images. In our method, a training set is generated from user-delineated features of manually-labeled examples; we subsequently train a classifier using the resultant training set. The overall process is described using imaging data acquired from an India-ink perfused C57BL/6J mouse brain using Knife Edge Scanning Microscopy. We illustrate the procedure through segmentation of cerebral vasculature structures from mechanical noise using trained classifiers...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28268545/fast-analytical-spectral-filtering-methods-for-magnetic-resonance-perfusion-quantification
#18
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/28263214/regional-cerebral-blood-flow-spect-and-mri-in-logopenic-variant-primary-progressive-aphasia
#19
Aristeidis H Katsanos, Spyridon Tsiouris, Chrissa Sioka, Anastasia Zikou, Andreas Fotopoulos
We report a 61-year-old woman who presented because of gradually progressive speech disorders. MRI scan revealed left temporal lobe atrophy with ex vacuo dilatation of the temporal horn and atrophy of the left inferior frontal gyrus and the left inferior parietal lobe. These findings in brain perfusion SPECT corresponded to a generalized hypoperfusion of the left hemisphere, particularly prominent on the rear parietal cortex and the temporal lobe. After taking into consideration the clinical presentation and imaging findings on MRI and SPECT, the diagnosis of the logopenic variant of primary progressive aphasia was finally reached...
March 3, 2017: Clinical Nuclear Medicine
https://www.readbyqxmd.com/read/28261040/changes-in-cerebral-blood-flow-during-an-alteration-in-glycemic-state-in-a-large-non-human-primate-papio-hamadryas-sp
#20
Peter Kochunov, Hsiao-Ying Wey, Peter T Fox, Jack L Lancaster, Michael D Davis, Danny J J Wang, Ai-Ling Lin, Raul A Bastarrachea, Marcia C R Andrade, Vicki Mattern, Patrice Frost, Paul B Higgins, Anthony G Comuzzie, Venkata S Voruganti
Changes in cerebral blood flow (CBF) during a hyperglycemic challenge were mapped, using perfusion-weighted MRI, in a group of non-human primates. Seven female baboons were fasted for 16 h prior to 1-h imaging experiment, performed under general anesthesia, that consisted of a 20-min baseline, followed by a bolus infusion of glucose (500 mg/kg). CBF maps were collected every 7 s and blood glucose and insulin levels were sampled at regular intervals. Blood glucose levels rose from 51.3 ± 10.9 to 203.9 ± 38...
2017: Frontiers in Neuroscience
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