An experimental study on cerebral ischemic penumbra imaging with ~(99)Tc~m-HL91

Objective To investigate the biodistribution of 99 Tc m-4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime (HL91) in rat model of middle cerebral artery occlusion (MCAO). Methods Thirty-one MCAO rats were established. Fourteen rats were used to study the biodistribution of 99 Tc m-HL91 and 15 rats were used to study the distribution of 99 Tc m-HL91 in the brain of MCAO model rats. Autoradiographic study of brain was also done in 16 MCAO model rats. Results The liver and kidney retention were higher than that in other tissues. At 1 h after injection, small intestine retention was also high.But radioactivity in normal brain was low. Retention in target site was higher than that in non-target site. Difference between subgroups of operation and that of pseudo-operation was significant( P 0.05 to P 0.001). Regional selective retention of 99 Tc m-HL91 at the target-ischemic area was shown in the autoradiograph. By using computer-enhanced image analysis, difference between target site and non-target site in the same autoradiograph and the differences between operation subgroups and that of pseudo-subgroups were all significant via Dunnett t -test and One-Way ANOVA. Conclusions 99 Tc m-HL91 can be avidly taken up by ischemic penumbra and target/non-target ratio is high. 99 Tc m-HL91 is a potential agent for hypoxic tissue imaging, and 99 Tc m-HL91 SPECT is a promising modality in detecting the ischemic penumbra.