Yoshitaka Tanabe

Serial Semiquantitative Imaging of Brain Damage Using Micro-SPECT and Micro-CT After Endothelin-1–Induced Transient Focal Cerebral Ischemia in Rats

In this study, we validated the use of 99mTc-hexamethylpropyleneamine oxime (99mTc-HMPAO) micro-SPECT combined with micro-CT for semiquantification of the infarct size after an experimental stroke in rats and compared our observations with those obtained from histology. This imaging strategy was applied to measure the longitudinal effect of mild hypothermia on the progression of brain damage after stroke in rats. Methods: The endothelin-1 model was used to elicit a transient focal cerebral ischemia in rats. This resulted in a reproducible insult in which the core is represented by the striatum and the penumbra by the cortex. Micro-SPECT and micro-CT images were taken at 1, 3, and 7 d after infusion of endothelin-1 and compared with those taken before the insult. After the last acquisition, rats were sacrificed and the infarct volume was determined via Nissl staining. The results obtained with micro-SPECT and micro-CT were compared with histology at the same time points. Mild hypothermia (33°C) was induced for 2 h, starting 20 min after the insult. Results: Brain damage was estimated using micro-SPECT and micro-CT and was reproducible with minimal interobserver variability. Normothermic stroke rats had reduced 99mTc-HMPAO uptake at 1 and 3 d after the insult, whereas hypothermia improved damage after stroke. These findings corroborate with histology at the same time points. At 1 wk after the insult, no reduction of radioactive uptake was observed in any treatment group. Conclusion: Micro-SPECT and micro-CT allow quick and reproducible semiquantification of brain damage as an interesting alternative to histology to measure the extent of infarcted tissue in small animals after stroke.

A simplified defaecographic procedure for the assessment of faecal incontinence or obstructed defaecation

Various types of defaecography have been reported for research purposes. A simplified method for clinical use has not been devised for the assessment of disordered defaecation. The aim of this study was to describe a simplified procedure of defaecography and evaluate its usefulness in the diagnosis of faecal incontinence or obstructed defaecation.