COMPARISON OF BRAIN SPECT USING TC-99M-BICISATE (L,L-ECD) AND [I-123]IMP IN CORTICAL AND SUBCORTICAL STROKES

Single photon emission computed tomography (SPECT) using Tc-99m-bicisa te and N-isopropyl-p-[I-123]iodoamphetamine ([I-123]IMP) was compared in 25 patients suffering cerebral ischemia during the subacute phase ( 7-14 days) of stroke. Patients were classified as cortical strokes (15 ) and subcortical strokes (10) according to clinical and CT data. Imag es were analyzed by five independent blinded observers. Then, using a crossmatching method between normal and abnormal brain areas, we evalu ated the sensitivity and specificity for Tc-99m-bicisate and [I-123]IM P and inter- and intraobserver reproducibility. A semiquantitative ana lysis was performed to compare abnormal hypoactive areas versus the co rresponding contralateral areas for Tc-99m-bicisate and [I-123]IMP in the two patient groups. There was no significant difference for sensit ivity and specificity between Tc-99m-bicisate and [I-123]IMP. Matching was similar to 90% in the two groups. The K-concordance index was sat isfactory and slightly better for Tc-99m-bicisate (0.485) than for [I- 123]IMP (0.435). Level of hypoactivity in the abnormal areas was signi ficantly higher for Tc-99m-bicisate (p < 0.03, n = 25) than for [I-123 ]IMP, especially for cortical strokes. This comparative study demonstr ates that Tc-99m-bicisate is a very useful tracer for the detection of focal cerebral ischemia by SPECT during the subacute phase of stroke.