Subacute and chronic cerebral infarctions: SPECT and gadolinium-DTPA enhanced MR imaging

Single photon emission computed tomography (SPECT) examinations of regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) were carried out in 23 patients with 19 subacute and 7 chronic cerebral infarctions. Corresponding magnetic resonance (MR) examinations (unenhanced and contrast enhanced scans) were done within a time interval of 2 days. Although all subacute lesions showed an increased rCBV, the rCBF could be either increased or decreased. Contrast enhancement in MR was associated with increased rCBV but not with increased rCBF. In all chronic lesions rCBV and rCBF were decreased and there was no contrast enhancement detectable in MR. The application of Gd-diethylenetriamine pentaacetic acid as contrast agent in MR demonstrates blood-brain barrier disruption as focal or gyral contrast enhancement in cerebral infarction. The SPECT examinations revealed an increased rCBV indicating a vasodilation or vasoparalysis. The rCBF was either increased or decreased depending on the collateral formation or recanalization of occluded vessels.