Purpose: The aim of this study was to compare the sensitivities of visual and densitometric analyses of CT scans and transcranial Doppler sonograms (TCD) in detecting early changes in acute stroke.
Methods: CT and TCD were each performed twice in 12 patients; first in the acute phase (within 28 hours of stroke onset), then in the subacute phase (mean +/- standard deviation, 6 +/- 3 days after onset) of a stroke. Hypodensity on the CT scans was evaluated visually, and the optical density of both the stroke region and the corresponding region on the unaffected side was measured. Measurement of flow parameters in the middle cerebral artery was carried out with TCD before or shortly (within 4 hours) after CT scanning.
Results: In the acute phase, blood flow velocities were significantly lower on the affected side than they were on the unaffected side (means, 42 +/- 13 and 55 +/- 25 cm/second, respectively; p = 0.012). Marked asymmetry in flow velocity was found in 3 of the 4 patients who had normal CT scans in the acute phase. The asymmetry in flow velocity disappeared by the sixth day after the stroke. The resistance index did not correlate with the final infarct size.
Conclusions: In some patients, the use of TCD in acute stroke may show alterations that reflect tissue damage that is undetectable on CT. Therefore, CT and TCD should be considered complementary diagnostic tools in the acute phase of stroke.
Copyright 2002 John Wiley & Sons, Inc.