FIG 1. Case 1: 54-year-old man with atrial fibrillation and sudden onset of left-sided hemiparesis.

A, ^99mTc-HMPAO SPECT image 4.5 hours after the onset of stroke shows hypoactivity in the right frontal and temporal lobes.

B, ^99mTc-HMPAO SPECT image (left) obtained 12 hours after the initial study shows hyperactivity in the right temporal lobe; a ^99mTc-ECD SPECT image (right) shows hypoactivity in the same area.

C, and D, CT scans after the SPECT study reveal a low-density area only in the right frontal lobe (C); 10 hours later, a partially hemorrhagic infarct has developed in the right temporal lobe (D).