Low Cerebral Blood Volume Is Predictive of Diffusion Restriction Only in Hyperacute Stroke

Abstract

Background and Purpose-Diffusion-weighted MRI (DWI) demonstrates ischemic tissue with high sensitivity. Although low cerebral blood volume (CBV) is also used as a marker for infarction, the quantitative relationship between diffusion abnormalities and CBV is unknown. We tested the hypothesis that CBV would decrease proportionally to the apparent diffusion coefficient in patients with acute stroke and thus could be used as a surrogate parameter for diffusion restriction. Methods-Perfusion-weighted imaging and DWI was performed in 54 patients within 28 hours of symptom onset. Mean apparent diffusion coefficient, cerebral blood flow, and CBV were measured within DWI lesions and contralateral regions. Results-Within DWI lesions, CBV (3.3Ϯ1.9 mL/100 g) was significantly decreased relative to contralateral regions (4.1Ϯ2.1 mL/100 g, PϽ0.001). Relative CBV was not decreased in patients with evidence of early reperfusion (1.2Ϯ0.5) or mild stroke (National Institutes of Health Stroke Scale Ͻ4, 1.1Ϯ0.6). Linear regression indicated that relative CBV was predictive of relative apparent diffusion coefficient only in patients imaged within 9 hours of symptom onset (Rϭ0.50, Pϭ0.02). Ischemic tissue volumes generated using a CBV threshold of the 50th percentile of normal tissue were correlated with DWI lesion volumes (Rϭ0.73, PϽ0.001). The mean difference between the CBV threshold of the 50th percentile of normal tissue and DWI lesion volumes was 6.3 mL (95% limits of agreement, 0.1 to 12.6 mL). Conclusions-Decreases in relative CBV are predictive of diffusion abnormalities in ischemic stroke. The pattern of CBV changes varies with clinical severity and symptom duration. Ischemic tissue volumes comparable to DWI lesions can be generated using CBV thresholds, but the use of this method is limited in patients with minor stroke. (Stroke. 2010; 41:2795-2800.)

Clinical Stroke Penumbra: Use of National Institutes of Health Stroke Scale as a Surrogate for CT Perfusion in Patient Triage for Intra-Arterial Middle Cerebral Artery Stroke Therapy

“…For instance, there is evidence that DWI infarct core may have high, low, or normal CBV depending on infarct age. 36 We acknowledge that CTP is not necessarily a criterion standard facilitating "correct" IAT triage with which the stroke scale group's decision should be compared. Our objective was to determine whether triage decisions with and without the use of CTP are analogous, with our hypothesis being that CTP does not significantly alter the triage decision that would have been made by using NIHSS without CTP.…”

Effects of salvianolic acid on cerebral perfusion in patients after acute stroke: A single‑center randomized controlled trial

“…Firstly, the study was semi-qualitative. However, relative PWI parameters are simply obtained and it has been observed that speculated CBV from rCBV is similar to that from volumetric assessment (44). In a previous study by the present authors, using the speculation method, it was revealed that 118% of the contra-, it was revealed that 118% of the contra-it was revealed that 118% of the contralateral CBV appeared in normal perfused patients and 77% in hypoperfused patients within DWI lesions; and surrounding the DWI lesion 121% of the contralateral CBV in normal perfused patients and 90% in hypoperfused patients, respectively; which suggests that >90% of the contralateral CBV may fit the metabolic demands of the hypoperfused tissues, and >120% of the contralateral CBVs may maintain a normal perfusion map (45).…”

Clinical Use of Computed Tomographic Perfusion for the Diagnosis and Prediction of Lesion Growth in Acute Ischemic Stroke

“…[5, 26, 27]Furthermore, CBV lesions can be reversible and appear to be time dependent. [28] Different CBV thresholds have been suggested for irreversible ischemia, depending on the size of the infarct[5], type of post-processing software[29, 30] or location of the lesion within the white or grey matter. [31] Indeed, there is no agreement yet on definitions and parameters of the ischemic core and penumbra using CTP parameters.…”