Different flow patterns in infarction of the middle cerebral artery.

Difficulties exist in distinguishing patients with currently recanalized mainstem occlusion of the middle cerebral artery (MCA) from branch occlusion. Thirty-five patients, 8 women and 27 men, at a mean age of 64 +/- 15 (standard deviation) years, with clinical signs of infarction in the MCA territory confirmed by computed tomography (CT), were evaluated by repeated clinical and transcranial Doppler sonography within 2 days of the event, 2 to 5 days later, and at 2 weeks after admission. The quotient MCA I/MCA C, derived to evaluate side differences, is defined as mean velocity (MV) in the MCA on the infarcted (I) side divided by MV in the MCA on the contralateral (C) side. Occlusion of the MCA was found in 13 of 35 patients at the first examination. A very high MV of 94 +/- 6 cm/sec with an abnormal turbulent flow pattern was found in 3 patients at the first examination, consistent with pseudostenosis after recanalization. The remaining 19 patients with a patent MCA had a lower MV in the affected side compared to the healthy side (37 +/- 15 and 54 +/- 20 cm/sec, p < 0.001). Five (38%) of 13 patients with acute MCA mainstem occlusions demonstrated recanalization at the second examination, within 1 week after the onset of stroke, with a MV of 82 +/- 44 cm/sec and pulsatility index (PI) of 0.68 +/- 0.38, which differed (p < 0.05) from the MV of 46 +/- 19 cm/sec and PI of 0.99 +/- 0.20 in the remainder. The MCA I/MCA C quotient revealed a difference (p < 0.01) between primarily patent vessels and recanalization at the second examination. A tendency to a better prognosis was found in originally patent or later recanalized vessels. Progression of neurological signs was noted in 3 (23%) of 13 patients with MCA occlusion and in 1 (4%) of 22 with nonoccluded MCAs.