Although
IMP scans fail to show fine anatomical details of the brain, because of poor resolution of a single head rotational system, adequate information is offered by the scans to localize most perfusion defects caused by
stroke. The following conclusions can be drawn from our study: 1. The planar
IMP brain scans processed through the computer are sensitive in the early diagnosis of
acute stroke except for small and deeply localized lesions. 2. The SPECT
IMP imaging is more sensitive than the planar or transmission CT scans in the early diagnosis of
stroke. Semiquantitative evaluations are feasible with
IMP SPECT. 3. Neither transmission CT nor
IMP SPECT are sensitive in the detection of acute
lacunar infarcts. 4. In acute
infarction, the transmission CT is usually negative or minimally positive in the early stages, while impaired uptake of
IMP occurs immediately after the onset of the
stroke. In
acute stroke, the extent of the perfusion defect on
IMP is usually greater than the abnormality seen on the transmission CT. 5. On followup studies,
IMP scans show improved perfusion reflecting physiologic changes, while transmission CT scans show further dense anatomical changes when compared to the initial studies. 6. Hyperemic changes are likely due to collateral circulation or luxury perfusion. This finding suggests that the
IMP reflects local cerebral blood flow in
strokes.