Dynamic CT perfusion imaging in the study of perihematomal cerebral blood flow after intracerebral hemorrhage in rats

Objective To establish a stable and reproducible experimental method of dynamic CT perfusion imaging in measurements of perihematomal cerebral blood flow after intracerebral hemorrhage (ICH) in rats, and to study its validation. Methods Seventy male Sprague-Dawley rats were randomly divided into ICH groups and sham-operated groups. ICH was produced by microinjection of 40 μl fresh autologous blood or saline into the right caudatum. Dynamic CT perfusion imaging in measurements of regional cerebral blood flow adjacent to hematomas was performed. Then, rats were sacrificed, and the TTC stain and histopathological examination were carried out. The ratios of side-to-side were measured at the regions around the hematomas by personal computer aided mapping. Results The gradient of perihematomal hypoperfusion was revealed by regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) maps in ICH groups. The alternation of rCBF around the hematomas were fluctuated, and rCBF reduction was most pronounced at 1 hour after ICH, then, the rCBF gradually returned, and returned to the peaks at 6 hours and 24 hours after ICH respectively. TTC stain did not show infarction around the hematoma. Histopathological study demonstrated there was a transitional zone between ICH and the normal brain tissue, and the astrocytic swelling and neuronal degeneration were observed in the peri-ICH regions. The inflammatory cell infiltration and capillaries hyperplasia were also seen around the ICH. Conclusion The method of dynamic CT perfusion imaging in measurements of perihematomal cerebral blood flow after intracerebral hemorrhage in rats is stable and accurate. Perfusion CT and its parameter analysis may play an increasing role in delineating the hypoperfusion around hematomas. The experimental method is suitable and validated to the study of secondly injury after ICH in vivo.