The evolution of the cerebral blood volume abnormality in patients with ischemic stroke: a CT perfusion study

Abstract

Background

Accurate identification of the acute infarct core abnormality is important for guiding acute stroke treatment. Abnormality volumes from diffusion-weighted MRI (DWI) and CT perfusion (CTP)-cerebral blood volume (CBV) are highly correlated. DWI lesions have been shown to be reversible at 24 h.

Purpose

To examine the temporal profile of the CT perfusion (CTP)-derived CBV abnormality out to 7 days post ischemic stroke.

Material and Methods

Twenty-six patients were included. Group A (n = 13) underwent a non-contrast CT (NCCT), CTP/CT angiography (CTA) within 6 h of stroke onset, CTP/CTA at 24 h, and CTP/NCCT at 5–7 days post stroke. Group B (n = 13) underwent a NCCT, CTP/CTA within 6 h of stroke onset, and NCCT at 5–7 days. Recanalization status was established in all patients. For both groups, infarct volumes were traced on 5–7 day NCCT images and superimposed onto all CTP-CBV functional maps to determine CBV. Group B (n = 13) admission images were used to define CBV infarct thresholds for gray and white matter. CBV-lesion over-estimation was determined for Group A using the thresholds from Group B.

Results

CBV (mL·100g^{− 1}; mean ± stdev) for gray/white matter, within confirmed infarcted regions (CBV_I) at admission, 24 h, and 5–7 days were 1.82 ± 0.56, 1.56 ± 0.42, 1.75 ± 0.31, and 1.38 ± 0.65, 1.13 ± 0.31, 1.32 ± 0.44, respectively, when averaged over all patients (P > 0.05). Four patients had tissue time-density curves from ischemic lesions (TDC_i) with an incomplete contrast medium wash-out phase (truncation) at admission and/or 24 h. Compared to admission, gray matter CBV_I was higher at 5–7 days for patients with TDC_i truncation (P < 0.05). There were no significant CBV_I increases for the eight patients without truncation (P > 0.05). Over-estimation of acute CBV lesion was present in 3/4 (75%) and 1/9 (11%) of patients with/without TDC_i truncation, respectively.

Conclusion

CTP-derived CBV lesion reversal is associated with TDC_i truncation during the acute stroke phase.