Diagnosis of middle cerebral artery occlusion with transcranial color-coded real-time sonography.

PURPOSE: To determine the usefulness of transcranial color-coded real-time sonography in detecting occlusion of the horizontal portion of the middle cerebral artery.

METHODS: Using transcranial color-coded real-time sonography, we measured the end-diastolic flow velocity with incident angle correction and the side-to-side ratio of the end-diastolic flow velocity (the end-diastolic ratio) in both middle cerebral arteries in 44 patients with or without occlusive disease. Cerebral angiography was carried out in all patients before or within 1 week after sonography. The subjects included 4 patients with unilateral stenosis of the extracranial internal carotid artery > or = 75%; ICS group), 6 with unilateral occlusion of the extracranial internal carotid (ICO group), 6 with occlusion of the horizontal portion of the middle cerebral artery (M1 group), and 28 without stenotic (< 75%) lesions in the internal carotid artery (control group).

RESULTS: In the control group, the end-diastolic flow velocity was 40.4 +/- 16.8 cm/s (mean +/- SD) and the end-diastolic ratio was 1.28 +/- 0.27. In the ICS and ICO groups, the end-diastolic flow velocities on the affected side and the end-diastolic ratios were 33.4 +/- 9.0 cm/s and 1.35 +/- 0.24, and 29.6 +/- 10.2 cm/s and 1.67 +/- 0.58, respectively. In the M1 group, the end-diastolic flow velocity (16.7 +/- 4.29 cm/s) on the occluded side was significantly lower than that in the other groups. The end-diastolic ratio (3.53 +/- 1.47) in the M1 group was significantly higher than that in the other groups.

CONCLUSION: The M1 group could be easily distinguished from the other groups on the basis of the end-diastolic ratio. Measurement of the end-diastolic flow velocity and the end-diastolic ratios in the middle cerebral artery by means of transcranial color-coded real-time sonography may help to identify an occlusion in the horizontal portion of the middle cerebral artery.