Lower Blood Pressure Is Not Associated With Decreased Arterial Spin Labeling Estimates of Perfusion in Intracerebral Hemorrhage

Abstract

Background Subacute ischemic lesions in intracerebral hemorrhage ( ICH ) have been hypothesized to result from hypoperfusion. Although studies of cerebral blood flow ( CBF ) indicate modest hypoperfusion in ICH , these investigations have been limited to early time points. Arterial spin labeling ( ASL ), a magnetic resonance imaging technique, can be used to measure CBF without a contrast agent. We assessed CBF in patients with ICH using ASL and tested the hypothesis that CBF is related to systolic blood pressure ( SBP ). Methods and Results In this cross-sectional study, patients with ICH were assessed with ASL at 48 hours, 7 days, and/or 30 days after onset. Relative CBF ( rCBF ; ratio of ipsilateral/contralateral perfusion) was measured in the perihematomal regions, hemispheres, border zones, and the perilesional area in patients with diffusion-weighted imaging hyperintensities. Twenty-patients (65% men; mean± SD age, 68.5±12.7 years) underwent imaging with ASL at 48 hours (N=12), day 7 (N=6), and day 30 (N=11). Median (interquartile range) hematoma volume was 13.1 (6.3-19.3) mL. Mean± SD baseline SBP was 185.4±25.5 mm Hg. Mean perihematomal rCBF was 0.9±0.2 at 48 hours at all time points. Baseline SBP and other SBP measurements were not associated with a decrease in rCBF in any of the regions of interest ( P≥0.111). r CBF did not differ among time points in any of the regions of interest ( P≥0.097). Mean perilesional rCBF was 1.04±0.65 and was unrelated to baseline SBP ( P=0.105). Conclusions ASL can be used to measure rCBF in patients with acute and subacute ICH . Perihematomal CBF was not associated with SBP changes at any time point. Clinical Trial Registration URL: http://www.clinicaltrials.gov . Unique identifier: NCT00963976.

Keywords: arterial spin labeling; blood pressure; intracerebral hemorrhage; magnetic resonance imaging.

Figure 1

A, The hematoma was delineated using susceptibility‐weighted images (SWIs; left), which were then coregistered with arterial spin labeling (ASL) scans (right). Regions of interest included perihematoma, hemisphere, internal and external border zones (IBZs and EBZs, respectively), and the contralateral homologous regions. B, Ischemic lesions were identified with diffusion‐weighted imaging (DWI) and coregistered with ASL scans. The area surrounding the ischemic lesion was compared with a homologous contralesional area.

Figure 2

Absolute arterial spin labeling (ASL) signal intensity values in the perihematomal, hemispheric, and internal and external border zone areas in the ipsilateral and contralateral sides to the hematoma at 48 hours (A), on day 7 (B), and on day 30 (C) were not different. D, The ipsilateral and contralateral absolute ASL signal intensity values were combined for all the time points for the participants with diffusion‐weighted imaging lesions, which did not differ either.

Figure 3

Perihematomal (A), ipsilateral hemispheric (B), and internal (C) and external (D) border zone relative cerebral blood flow (rCBF) values in individual patients. ANOVA results indicated no differences over time in any of the regions examined.

Figure 4

A, Temporal profile of mean (95% CI) of systolic blood pressure (SBP) profile up to 48 hours, as well as at day 7 and day 30. SBP at 48 hours was not associated with relative cerebral blood flow (rCBF) in the perihematoma (B), hemisphere (C), or border zones (D).