The correlation between quantitative T2' and regional cerebral blood flow after acute brain ischemia in early reperfusion as demonstrated in a middle cerebral artery occlusion/reperfusion model of the rat.

Abstract

qT2'-maps are calculated by subtracting T2- from T2*-relaxation rates. They are oxygen-sensitive and depict oxygen extraction. In several studies they have been used to describe the penumbra in patients with acute ischemic stroke. No correlation between rCBF and qT2' has been performed to date. In this study a correlation between rCBF and qT2' was performed in a temporary middle cerebral occlusion-reperfusion model of the rat.
Temporary middle cerebral artery occlusion was performed on seven Sprague-Dawley rats. After 60 min of occlusion and 90 min of reperfusion MRI was performed including DWI, dynamic susceptibility contrast-weighted MR imaging (DSC-MRI) and qT2'. ROIs were placed inside the DWI lesion and transferred to rCBF- and qT2'-maps. rCBF and qT2' were compared to corresponding tissue in the contralateral hemisphere.
qT2' was lower in the infarcted areas when compared to the contralateral hemisphere. Correlation between rCBF and qT2' was r = 0.41, p = 0.14 (Pearson's correlation coefficient), when corrected for outliers it was r = 0.58, p = 0.04.
Our results show that there is a moderate correlation between rCBF and qT2'. qT2'-maps could be used to explore cerebral perfusion without the application of contrast agent or radiation.