Initial Imaging Modality in Patients with Acute Ischemic Stroke

Lee, Jeong Sik; Lee, Hui Joong; Ryoo, Hyun Wook; Seo, Kang Suk; Park, Jeong Bae; Jung, Jae Myung; Kim, Young Sun

Abstract

PURPOSE: Though their clinical effectiveness of intra-arterial thrombolytic treatment has been proven, there is still some controversy in the choice of baseline imaging study for selecting particular hyper acute stroke patients who would benefit from thrombolysis from among patients with hyper acute stroke. In spite of their excellent resolution MR images has limitations for use in a baseline study because of their cost. The purpose of this study was to assess which baseline study, CT image or diffusion-weighted image, was more beneficial in evaluating hyper acute stroke patients who might particularly benefit from intra-arterial thrombolysis of the middle cerebral artery occlusion.
METHODS
We divided the patients into two groups: those for whom CT was used for the initial imaging modality and those for whom MRI was used. We compared in-hospital time delay and the disadvantage of time consumed in evaluating of patients between the two groups. Baseline and 24-hour follow-up CT or MR scans of patients treated with intra-arterial thrombolysis were retrospectively scored by using the Alberta Stroke Program Early CT Score (ASPECTS).
RESULTS
The analysis included 64 patients with angiographically confirmed middle cerebral artery occlusion. Although there was significant time delay in obtaining a MR diffusion weighted image (130.20+/-71.63 min) compared to a CT scan (73.64+/-28.99 min) (p<0.001), there were no significant clinical loss scored by using National Institutes of Health Stroke Scale (NIHSS) (p=0.676) and no significant difference in the prognosis estimated by using the modified Rankin scale (p= 0.162). Diffusion weighted images showed significantly higher ASPECT score (p=0.028) in the good prognosis group, and the ROC curve revealed the diffusion weighted images to be better indication for intra-arterial thrombolysis.
CONCLUSION
According to our results, MR diffusion weighted images were more useful than CT scans for predicting the outcome of intra-arterial thrombolytic treatment. Our results suggest MR diffusion weighted images can replace CT scans for baseline imaging studies for hyperacute stroke patients.