Preliminary experience with 99mTc-HMPAO SPECT in cerebral ischaemia

To assess the sequential changes seen in cerebral blood flow using Single Photon Emission Computed Tomography with 99mtechnetium-hexamethylpropylene amine oxime (99mTc-HMPAO SPECT) in acute ischaemic stroke, 35 patients were prospectively studied from June 1990- to March 1991. Scans were performed during the acute phase (1-7 days), sub-acute phase (8-21 days) and chronic phase of stroke (greater than 1 month). Nine patients underwent scans in all 3 phases, 15 patients had 2 scans, and 11 patients had one scan. The majority of infarcts were in the middle cerebral territory (15 patients), while 4 infarcts were in the posterior cerebral territory and two in the anterior cerebral territory. There was a total of 4 lacunar infarcts. Image analysis was by visual inspection and by semiquantitation using homologous regions of interest in opposite hemispheres. SPECT in the acute phase identified the final vascular territory affected in 19 of 27 patients. There were 8 patients in whom early SPECT predicted the vascular territory as seen on late CT scan when the early CT scan was normal. Hyperaemia or reperfusion in the involved vascular territory was identified in 10 patients on scans performed during the sub-acute phase. Late SPECT scans showed perfusion defects greater than the infarct size seen on CT scan in the majority of patients. In all cases, the perfusion defect on the late SPECT scan was equal to or larger than the defect seen on the acute or sub-acute scan. Crossed cerebellar diaschisis was identified in 8 patients, and cortical/subcortical diaschisis in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)