Selective Magnetic Resonance Angiography as a Functional Dynamic Study in Ischemic Stroke

ABSTRACT

Recently, techniques of magnetic resonance angiography(MRA) have been developed that permit a three dimensional display of vessel without infusion of a contrast agent. However, to be competitive with conventional angiography(CA). MRA should show not only morphology of vessel but should also provide functional inforrnation, as selective delineation of specific vascular territories. Selective presaturation of individual vessels causes signal loss within the territory supplied by the presaturated artery, without affecting vessels not crossing the presaturation slab. We applied the selective MRA to the study of blood flow dynamics in five patients wiih ischemic stroke, showing patent middle cerebral arteIy in spite of obstruction or severe stenosis of the ipsilateral internal carotid artery on MRA. Selective MRA was able to demonstrate the direction of blood flow and presence of collateral blood flow. Findings of selective MRA were correlated with those from CA. Selective MRA can be used as a noninvasive and useful means for imaging the blood supply of the major intracranial arteries.