Abstract T P37: Cerebral Blood Volume Does Not Differentiate Regions With Persistent Cerebral Hypoperfusion That Infarct From Those That Survive: A DEFUSE 2 Substudy
Background: The optimal Tmax threshold for predicting critically hypoperfused tissue is a delay of >6 seconds. However, persistent Tmax >6s lesions do not invariably progress to infarction. Differences in cerebral blood volume (CBV) may explain why some regions of persistent cerebral hypoperfusion (PCHP) infarct whereas others survive. We hypothesized that CBV is higher in areas of PCHP that survive versus those that infarct.
Methods: We included patients that had: 1) a Tmax >6s lesion on baseline and early follow-up MRI perfusion scans, and 2) a FLAIR lesion on the day 5 MRI scan. Regions of PCHP had to meet two criteria: 1) Tmax >6s positive on both baseline and co-registered early follow-up MRI perfusion scans, and 2) DWI negative on the baseline MRI scan. PCHP regions were classified as PCHP-infarct if there was a corresponding lesion on the co-registered 5 day FLAIR and as PCHP-survival if there was no corresponding lesion. Patients with no region of either PCHP-infarct or PCHP-survival were excluded. The study had two parts. In part 1, the paired t-test was used to compare lesion volume, CBV, cerebral blood flow (CBF), mean transit time (MTT), and Tmax between PCHP-infarct and PCHP-survival regions within each patient. In part 2, the 2-sample t-test was used to compare mean volume, CBV, CBF, MTT, and Tmax in PCHP-infarct and PCHP-survival regions for all patients together as a group.
Results: 61 patients were included in the analysis. Mean total PCHP volume was 26cc (16cc infarct, 10cc survival) and median total PCHP volume was 15cc (9cc infarct, 6cc survival). For part 1, CBV was not different in PCHP-infarct versus PCHP-survival (P=0.16). CBF was higher (P=0.05) in regions of PCHP-survival, and MTT and Tmax were less prolonged (P=0.03 and P < 0.01). For part 2, mean CBV and MTT did not differ between PCHP-infarct and PCHP-survival (P=0.23 and P=0.40). Mean CBF trended higher (P=0.07) and mean Tmax delays were milder (P= 0.04) in PCHP-survival.
Conclusion: CBV does not differ between regions of PCHP-infarct versus PCHP-survival and does not explain why some areas of persistent, severe hypoperfusion survive. Tmax was less severely delayed and CBF values were higher in regions of PCHP-survival, which warrant further study.
Author Disclosures: S.K. Mann: None. S. Christensen: None. M. Mlynash: None. S. Kemp: None. M.G. Lansberg: None. G.W. Albers: Ownership Interest; Modest; equity interest: iSchemaView.
- © 2014 by American Heart Association, Inc.