In the present study, we report on the hemodynamic mechanism of appearance of hemiparesis after aneurysmal subarachnoid hemorrhage (SAH), usefulness of intracisternally located echography to detect narrowing of the first segment (M1 segment) of the middle cerebral artery, clinical introduction of dynamic digital subtraction angiography (dynamic DSA) to measure local transit time in the territory of spastic intracranial vessels, and finally the clinical results of endovascular treatment using percutaneous transluminal angioplasty and/or papaverine hydrochloride.
Appearance of hemiparesis due to delayed vasospasm was thought to be caused by decrease in blood flow in the corona radiata fed by lenticulostriate arteries and medullary arteries of the middle cerebral artery. Intracisternally located echography detected a decrease in inner diameter of M1 segment. When the mean transit time lasted over 5.52 sec just after endovascular treatment for delayed vasospasm, cerebral infarction occurred, resulting in motor and/or cortical deficits. Thirteen (56.5%) of 23 patients endovascularlly treated for delayed vasospasm, resulted in good recovery more than three months after onset of SAH.