Evaluation of cerebral blood flow data in stroke patients using a mapping system (original) (raw)
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An Analysis of Laterality in Acute Arterial Stroke and Its Associations
Journal of Evolution of Medical and Dental Sciences, 2017
BACKGROUND Stroke is defined as a sudden loss of brain function caused by a decreased cerebral blood flow. The objective of this study was to find out the association between laterality of stroke and age group, gender, type of stroke and anatomical site. MATERIALS AND METHODS A retrospective descriptive study was designed to collect the reports of consecutive cranial computerised tomography (CT) scan taken over a period of seven months commencing from September 2016. The details of patients' age, gender, stroke type, anatomical site and laterality of acute arterial stroke were entered in Excel spread sheet and analysed statistically using Chi square test with Yates' correction. RESULTS Among 2,020 cranial CT scans, only 182 satisfied the eligibility criteria of stroke and thus the prevalence of acute arterial stroke was 9% among the study population. The ratio between non-haemorrhagic and haemorrhagic stroke was 5.7:1. Of the 155 nonhaemorrhagic strokes, 77 (49.6%) belonged to middle cerebral, 38 (24.5%) to posterior cerebral and two (1.2%) to anterior cerebral artery territory. The anatomical location of haemorrhage was significantly more in striatum (44.4%) among the study group and it was followed by lobar (22.2%), thalamus (18.5%), cerebellum (7.4%), pons (3.7%) and interventricular sites (3.7%). Bilateral lesions were noticed among 14.8% of non-haemorrhagic infarcts but none in haemorrhagic infarcts. CONCLUSION Overall right-sided lesions were noticed significantly more among males of all age groups among the non-haemorrhagic stroke cases, whereas there was no preferential laterality in haemorrhagic group.
Cerebral blood flow and neuropsychological asymmetries in unilateral stroke
Stroke, 1991
This study sought to determine the degree of agreement between asymmetries of neuropsychological functioning and nine methods of quantifying asymmetries of regional cerebral blood flow. The regional cerebral blood flow methods combined three markers of cerebral blood flow asymmetry (percent hemispheric difference, maximum percent probe-pair asymmetry, and number of probe-pair asymmetries) with three indexes of regional cerebral blood flow (fast compartment flow, initial slope index, and initial slope). Eleven patients with left hemispheric ischemic strokes and 13 with right hemispheric ischemic strokes were studied with the xenon-133 inhalation technique and neuropsychological tests. Blind clinical judgments of neuropsychological asymmetry significantly correlated with all nine methods of cerebral blood flow asymmetry determination; correlations ranged from -0.42 to -0.77. Clinical judgment of asymmetry of neuropsychological functioning accurately predicted the hemisphere of lower f...
Determination of Regional Cerebral Blood Flow in Patients With Cerebral Infarction
Archives of Neurology, 1984
A method for estimating regional cerebral blood flow is described in which tracer amounts of 138 Xe are inhaled for 2 min and monitored extracranially over the next 45 to 60 min. A three-compartment model used to analyze the resulting clearance curves provided separate blood flows for "gray" and "white" matter, plus a decay constant for a slow third component, believed to arise from extracerebral tissue. The analysis included a correction for recirculation of all three components, based on radioisotope concentration of the expired air or arterial blood. Results from the analysis were compared with those obtained by the more traditional two-compartment approach, using data from 15 healthy young males. Whereas the three-compartment method yielded measurements comparable with those obtained by established techniques (average CBF = 54.7 ml/100 g/min), the two-compartment analysis gave consistently lower values (average CBF = 30.2). Comparison of results based on expired air and arterial sampling suggested that end-expiratory air is a reasonable substitute for arterial blood. Although the I3S Xe inhalation method is technically simpler and less traumatic than other methods, complex analytic treatment of the data is necessitated by the presence of appreciable recirculation and extracerebral contamination. ADDITIONAL KEY WORDS three-compartment analysis extracerebral contamination arterial isotope concentration recirculation COo inhalation cerebral clearance curves two-compartment analysis expired air sampling man • In 1963 Lassen and co-workers (1) introduced a method for measuring regional cerebral blood flow in man that has yielded results (2, 3) consistent with older established techniques. This method involves the extracranial monitoring of an inert, diffusible radioisotope (85-krypton or 133-xenon) injected into the internal carotid artery. The clearance curves so obtained are subjected to a twocompartment analysis (4, 5) in which separate
2010
Background and Purpose-The National Institutes of Health Stroke Scale (NIHSS) is an established measure of neurological impairment; however, it can award more points for tests of presumed left-hemisphere function, such as language, than for tests of right-hemisphere function, such as neglect. This difference may be important if a low NIHSS score is used to exclude patients with right-hemisphere stroke from clinical trials or established treatments. The aim of this study was to investigate whether the relationship between acute NIHSS score and acute stroke volume as determined by acute diffusion-and perfusion-weighted MRI (DWI and PWI) differs between right-and left-sided stroke. Methods-This was a retrospective study of 153 patients with acute stroke seen at Beth Israel Deaconess Medical Center between January 1995 and March 2000 who underwent an MRI examination and NIHSS within 24 hours of stroke onset. NIHSS score was recorded prospectively by the admitting stroke fellow at the time of acute presentation, immediately preceding imaging. Computerized volumetric analysis of the MRI lesions was performed by investigators blinded to clinical data. Results-There were significant correlations between the acute NIHSS scores and acute DWI lesion volumes (rϭ0.48 right, rϭ0.58 left) and between acute NIHSS scores and perfusion-weight imaging hypoperfusion volumes (rϭ0.62 right, rϭ0.60 left). For patients with NIHSS scores of 0 to 5, the DWI volume of right cerebral lesions was greater than that of left-sided lesions (mean volume, 8.8 versus 3.2 cm 3 ; Pϭ0.04). Among patients with DWI lesions larger than the median volume (9 cm 3), 8 of 37 with right-sided stroke had an NIHSS score of 0 to 5 compared with 1 of 39 patients with left-sided stroke (Pϭ0.01). Multiple linear regression analysis revealed a significantly lower acute NIHSS on the right compared with the left side when adjusted for stroke volume on chronic T2 imaging (Pϭ0.03). Conclusions-Patients with right-sided stroke may have a low NIHSS score despite substantial DWI lesion volume. Acute imaging information, such as that available with multimodal MRI, may be useful to identify patients for inclusion in acute stroke protocols when there is clinical uncertainty about eligibility. Prospective evaluation of criteria incorporating acute imaging data is required.
AJNR. American journal of neuroradiology, 2001
Knowledge of cerebral blood flow (CBF) alterations in cases of acute stroke could be valuable in the early management of these cases. Among imaging techniques affording evaluation of cerebral perfusion, perfusion CT studies involve sequential acquisition of cerebral CT sections obtained in an axial mode during the IV administration of iodinated contrast material. They are thus very easy to perform in emergency settings. Perfusion CT values of CBF have proved to be accurate in animals, and perfusion CT affords plausible values in humans. The purpose of this study was to validate perfusion CT studies of CBF by comparison with the results provided by stable xenon CT, which have been reported to be accurate, and to evaluate acquisition and processing modalities of CT data, notably the possible deconvolution methods and the selection of the reference artery. Twelve stable xenon CT and perfusion CT cerebral examinations were performed within an interval of a few minutes in patients with v...
Stroke, 2009
Background and Purpose-Perfusion-weighted MRI-based maps of cerebral blood flow (CBF MRI) are considered a good MRI measure of penumbral flow in acute ischemic stroke but are seldom used in clinical routine due to methodical issues. We validated CBF MRI on quantitative CBF measurement by 15O-water positron emission tomography (CBF PET). Material and Methods-Comparative CBF MRI and CBF PET were performed in patients with acute and subacute stroke. In a voxel-based seed-growing technique, predefined CBF MRI thresholds (Ͻ40, Ͻ30, Ͻ20, Ͻ10 mL/100 g/min) were applied and the resulting volumes were compared with the hypoperfusion volume detected by the penumbral threshold (Ͻ20 mL/100 g/min) on CBF PET. The volumetric comparison was expressed as the C-ratio (volume CBF MRI /volume CBF PET) to identify the best MRI threshold. The influence of vessel pathology, hypoperfusion size, and time point of imaging was described. The proportion of voxels correctly classified as hypoperfused and the proportion of voxel correctly classified as nonhypoperfused of the best CBF MRI threshold was calculated and a Bland-Altman plot illustrated the method-specific differences. Results-In 24 patients (median time MRI to PET: 68 minutes; 16 patients imaged within 24 hours after stroke), the median volume of hypoperfusion Ͻ20 mL/100 g/min (CBF PET) was 78.5 cm 3. Median hypoperfusion volume on CBF MRI ranged from 245.9 cm 3 (Ͻ40 mL/100 g/min) to 35.5 cm 3 (Ͻ10 mL/10 g/min). On visual inspection, an excellent qualitative congruence was found. The quantitative congruence was best for the MRI-CBF threshold Ͻ20 mL/100 g/min (median C-ratio: 1.0), reaching a proportion of voxels correctly classified as hypoperfused of 76% and a proportion of voxel correctly classified as nonhypoperfused of 96%, but a wide interindividual range (C-ratio 0.3 to 3.5) was found. Ipsilateral vessel pathology, time point of imaging, and size of hypoperfusion did not significantly influence the C-ratio. The Bland-Altman analysis for the volumetric difference of CBF MRI and CBF PET found a good overall agreement but a large SD. Conclusion-Hypoperfusion areas below the CBF PET penumbral threshold can be well identified by the CBF MRI threshold Ͻ20 mL/10 g/min at a group level, but a large individual variance (exceeding 20% of volume in nearly half of the patients) could not be explained. Our results support a prudent use of MRI-based quantitative CBF measurement in clinical routine.
Flow Territory Mapping of the Cerebral Arteries With Regional Perfusion MRI
Stroke, 2004
Background and Purpose-Conventional contrast-enhanced angiography is the gold standard for visualization of the vascular tree supplied by the major cerebral arteries and assessment of collateral flow. Thus far, however, no methods are available to assess the actual flow territories of the individual cerebral arteries. In the present study, we evaluate a noninvasive arterial spin labeling MRI method for selective mapping of the flow territories of the left and right internal carotid arteries and posterior circulation (basilar artery and vertebral arteries). Methods-A spatially selective labeling approach, regional perfusion imaging, was developed on the basis of selective slab inversion of the arterial water with a pulsed arterial spin labeling sequence. The selectivity of this method was demonstrated. Results-Regional perfusion imaging enables assessment of the perfusion territories of the major cerebral arteries. With selective labeling of an internal carotid artery, signal is present in both the ipsilateral anterior cerebral artery and ipsilateral middle cerebral artery flow territory. With labeling of the basilar artery, perfusion-weighted signal is symmetrically present in both posterior cerebral artery flow territories. Cerebral blood flow values measured with regional perfusion imaging in the complete hemisphere (40.1 mL • min Ϫ1 • 100 g Ϫ1 tissue), white matter (22.1 mL • min Ϫ1 • 100 g Ϫ1 tissue), and gray matter (65.8 mL • min Ϫ1 • 100 g Ϫ1 tissue) are in agreement with data in the literature. Conclusions-We present the first imaging method capable of evaluating both quantitatively and qualitatively the flow territories of the individual brain-feeding arteries in vivo. (Stroke. 2004;35:882-887.) Key Words: cerebral blood flow Ⅲ cerebral ischemia Ⅲ circle of Willis Ⅲ collateral circulation Ⅲ magnetic resonance imaging