Abstract
We characterize the usefulness of diffusion-weighted MRI (DWI) in revascularization therapy of acute cerebral main trunk occlusion. Twenty patients who underwent revascularization therapy were studied: 17 underwent local intra-arterial fibrinolysis (LIF) and 3 underwent embolectomy. Complete recanalization was obtained in 18 of the 20 patients. In the remaining 2 patients, recanalization was partial. Initial DWI in the acute phase was performed 30 minutes to 6 hours after onset, and the DWI findings could be classified into 4 types. In 17 patients with complete recanalization, the hyperintensity areas (HIAs) on the initial DWI were changed to infarctions after recanalization, and in 5 of these patients, infarcted areas became more extended than the initial hyperintensity areas. Three patients with the type 1 finding (no HIA) made good recovery after recanalization and follow-up MRI showed no abnormal intensity, except for 1 patient. In 5 patients with the type 2 finding (HIAs in the perforator's territories), 3 patients with complete recanalization made good recovery, but 2 patients with partial recanalization had a hemorrhagic event in the hyperintensity area on the initial DWI. In 10 patients with the type 3 finding (scattered HIAs in the cortex), clinical outcome of the therapy depended on the location of hyperintensity area on initial DWI. In 2 patients with the type 4 finding (extended HIAs), 1 patient showed clinical improvement and the hyperintensity area on follow-up MRI became smaller than that on the initial DWI. The other patient had a hemorrhagic event with a fatal outcome.
A comparison of clinical outcome between revascularization and conservative therapy group showed the incidence of good outcome was higher in the revascularization groups of type 1, 2 and 3.
DWI could be a useful diagnostic technique for detecting severe ischemic and perhaps irreversibly damaged lesions. The initial DWI provided valuable and reliable information and our proposed classfication of initial DWI findings could be a valuable indicator in the revascularization therapy.
