Transcranial doppler sonography and CT angiography in patients with atherothrombotic middle cerebral artery stroke

Abstract

Background and purpose: Atherothrombotic disease of the middle cerebral artery (MCA) frequently occurs in Asian populations. This abnormality can be noninvasively assessed with transcranial Doppler sonography (TCD) and computed tomographic angiography (CTA). To our knowledge, the usefulness of TCD sonography compared with CTA in the diagnosis of nonembolic MCA disease has not been studied.

Methods: We prospectively examined 70 patients with clinically suspected atherothrom botic MCA stroke by using TCD sonography and CTA. We excluded patients with a known source of cardiac emboli, significant carotid stenosis, or classic lacunar syndrome. TCD sonography was performed within 2 days of admission, followed by CTA within 7 days after stroke onset.

Results: CTA demonstrated MCA stenosis of more than 50% in 57 patients (81%), whereas only 29 patients (41%) had abnormal TCD findings. CTA showed proximal M1 stenosis, distal M1 stenosis, and M2 disease in 29%, 29%, and 24% of the patients, respectively. Stenotic sites differed between patients with normal TCD results and those with abnormal results. TCD findings correlated well with CTA findings in all patients with proximal M1 stenosis. In contrast, TCD sonography correctly depicted distal M1 or M2 disease in only 24% of the patients.

Conclusion: In this population, CTA is superior to TCD sonography in the diagnosis of MCA disease. Abnormal TCD results are highly suggestive of MCA stenosis. However, normal TCD findings do not exclude such lesions, especially in patients with distal M1 or M2 disease. Because distal M1 and M2 disease was found in half of our patients, TCD sonography should not be used as a method to screen for MCA stenosis.