Early CT perfusion mismatch in acute stroke is not time-dependent but relies on collateralization grade.
INTRODUCTION
Factors that determine the extent of the penumbra in the initial diagnostic workup using whole brain CT Perfusion (WB-CTP) remain unclear. The purpose of the current study was to determine a possible dependency of the initial mismatch size between cerebral blood flow (CBF) and cerebral blood volume (CBV) from time after symptom onset, leptomeningeal collateralization, and occlusion localization in acute middle cerebral artery (MCA) infarctions.


METHODS
Out of an existing cohort of 992 consecutive patients receiving multiparametric CT scans including WB-CTP due to suspected stroke, we included patients who had (1) a witnessed time of symptom onset, (2) an infarction of the MCA territory as documented by follow-up imaging, and (3) an initial CBF volume of >10 ml. CBF and CBV lesion sizes, collateralization grade, and the site of occlusion were determined.


RESULTS
We included 103 patients. Univariate analysis showed that time from symptom onset (168 +/- 91.2 min) did not correlate with relative or absolute mismatch volumes (p = 0.458 and p = 0.921). Higher collateralization gradings were associated with small absolute mismatch volumes (p = 0.004 and p < 0.001). Internal carotid artery (ICA) occlusions were associated with large absolute mismatch volumes (p = 0.004). Multivariate analysis confirmed that ICA occlusion was associated with large absolute mismatch volumes (p = 0.005), and high collateral grade was associated with small absolute mismatch volumes (p = 0.017).


CONCLUSIONS
There is no significant correlation between initial CTP mismatch and time after symptom onset. Predictors of mismatch size include the extent of the collaterals and a proximal location of the occlusion.
['von Baumgarten|Louisa|L|', 'Thierfelder|Kolja M|KM|', 'Beyer|Sebastian E|SE|', 'Baumann|Alena B|AB|', 'Bollwein|Christine|C|', 'Janssen|Hendrik|H|', 'Reiser|Maximilian F|MF|', 'Straube|Andreas|A|', 'Sommer|Wieland H|WH|']
D000368:Aged D000369:Aged, 80 and over D001810:Blood Volume D002560:Cerebrovascular Circulation D015331:Cohort Studies D003097:Collateral Circulation D006801:Humans D008875:Middle Aged D020521:Stroke D013997:Time Factors D014057:Tomography, X-Ray Computed
CT perfusion Leptomeningeal collateralization Acute ischemic stroke Flow-volume mismatch Penumbral imaging