Comparison of brain DEATH scintigraphy and pathology results in a rat model

Brain Death is defined as the complete loss of the brain functions due to the occurrance of any event. The developments in the transplantation surgery field has made the early diagnosis of the brain death much more important than before. So it is necessary to support the clinical diagnosis of brain death by the laboratory methods. The brain scintigraphy with Tc 99m DTPA is a very sensitive diagnostic method that shows cerebral blood flow loss that occured after the brain death. Cerebral blood flow can be estimated quantitatively by this method. Non-hydrophilic agents such as Tc 99m HMPAO and Tc 99m ECD might also demonstrate brain parenchymal activity besides the cerebral blood flow. Comparison of the histopathological changes occured at the same time with the decrease of the cerebral blood flow as shown by Tc 99m DTPA brain death scintigraphy after the brain death in an experimental model was aimed in this study. The study included examination of the cerebral blood flow by Tc 99m DTPA brain scintigraphy in the 20 rats, one day before the brain death model was performed and after production of the brain death model in living eleven rats. Tc 99m DTPA brain scintigraphy was performed under entubation and monitorization. Mann Whitney U test method was performed for the comparison between the groups (scintigraphical quantification results before and after brain death). In the time activity curves generated from analysis of the scintigraphies significant decrease in the levels of counts in the brain death group were obtained especially in the arterial phase (p<0,01). Also the decrease of the cerebral blood flow between the first and the sixth minutes was found statistically significant (p<0,05). Common principal histopathological changes, autolysis and color loss in the nerve cells and diffuse edema, rare petechial hemorrhage in the brain tissues were observed after the experiment in all cases. To conclude, the quantitative findings of the brain scintigraphy by Tc 99m DTPA was related with the histopathological findings observed during the early periods in the brain death with the absence of the cerebral blood flow. The quantification of Tc-99m DTPA brain death scintigraphy shows the cerebral blood flow, which might indicate the certain diagnosis of the brain death and thus, the potential donors can be determined earlier which leads to the increased transplantation rates. Key words: Brain Death, Tc 99m DTPA, cerebral blood flow, histopathological findings.