[Degree of hemodynamic disturbance at the hyperacute phase of stroke: predictive value of 3D-TOF angiography and the T2 fast-FLAIR sequence].

GOAL: To define during the hyperacute phase of stroke the value of 3D-TOF MR angiography (MRA) and T2 fast-FLAIR sequence for predicting the volume of tissue presenting a hemodynamic disturbance.

MATERIAL: and method: Thirty-five cases of hyperacute stroke located in following territories: middle cerebral artery (MCA) (n=29), anterior choroidal artery (AChoA) (n=5) and watershed (n=1) were retrospectively reviewed. The vascular abnormalities defined on MRA (vessel stenosis or occlusion) or FLAIR sequence (vessel hyperintensity) were classified into 3 groups: normal (I), distal abnormalities (II), abnormalities of the entire arterial territory (III). These results were compared with the volume of tissue showing a prolonged mean transit time (MTT) determined on relative MTT maps calculated from bolus tracking MR perfusion images.

RESULTS

The abnormal volume measured on the MTT map was significantly correlated to the results of the MRA and FLAIR sequence. In the 12 cases of group III defined on the MRA (abnormality from M1), the volume of hemodynamic disturbance was always higher than 100 ml. For the MCA territory, it was not possible to predict the presence of a hemodynamic disturbance in any of the 3 groups defined on the FLAIR sequence and in the groups I and II defined on the MRA. For the AChoA territory, a hemodynamic disturbance was never observed in groups I and II defined either on MRA or FLAIR sequence.

CONCLUSION

When there was no flow within the M1 segment on the MRA, there was always a hemodynamic disturbance larger than 100 ml on the MTT map. In the case of AChoA ischemic lesion, when no vascular abnormality was observed on the MRA or FLAIR images, the MTT map was always normal.