Posterior cerebral artery occlusion: clinical, computed tomographic, and angiographic correlation.

The distribution of low-density areas on computed tomography (CT) suggested occlusions in the proximal half of the circummesencephalic portion in 38 patients with posterior cerebral artery (PCA) occlusion. Correlation between clinical, CT, and angiographic findings in 24 cases showed that occlusion was most common in the crural segment. Clinical manifestations and infarction extension varied widely among proximal occlusions. In cases with good collateral filling, the infarction was restricted to the thalamus; in those with poor filling, it involved most of the PCA's territory, and hemorrhagic transformation occasionally ensued. Discrepancies between findings were ascribed to dislodging of emboli or thrombi, recanalization, and transient obscuration of the infarction on CT.