Purpose: To determine the prevalence of the hyperdense middle cerebral artery sign (HMCAS) in an acute stroke population (treated with intravenous tissue plasminogen activator (tPA) within 90 minutes of stroke onset); to correlate the presence/absence of the sign with arteriographic findings; and to correlate the HMCAS with the volume of subsequent infarction.
Patients and methods: 55 patients with acute ischemic stroke underwent CT to exclude cerebral hemorrhage and were then treated with intravenous tPA. The neuroradiologist, blinded to the clinical and arteriographic data, sought the HMCAS on the initial and subsequent scans.
Results: The HMCAS was detected by CT in 19 of 55 (34.5%) patients (one false positive). Arteriograms in 14 of the 18 true positive patients confirmed the CT-predicted middle cerebral artery segment in 12. The 18 patients developed infarcts larger than patients not exhibiting the sign (132 cc vs 52 cc, P less than .002).
Conclusion: The HMCAS does predict middle cerebral artery occlusion and subsequent development of a large infarct.