Histological Effect Caused by Contrast Solution Injection for Post Mortem Computed Tomography Angiography in Dogs

The post mortem computed tomography angiography (PMCTA) is a technique that uses a contrast solution to evaluate the vascular structures in cadavers. This study aims to verify if there is any tissue impairment in parenchymatous organs after PMCTA in dogs. PMCTA was performed in 9 cadavers, divided into 3 groups. There is 23% volemia of contrast solution in groups 1 and 2, and 46% in group 3. Iodine contrast was diluted in polyethylene glycol in groups 1 and 3, and in soybean oil in group 2. Tissue samples were collected from lungs, liver and kidney before and after the PMCTA. The contrast perfusion of each target-organ was measured through CT images by the increased attenuation of Hounsfield units. Each histological sample was evaluated according to its correspondence with the sampling organ and its quality. The presence of artifacts was also assessed and the histological findings were described. The sample quality was attributed a score between 0 and 2. The histological findings were compared for samples collected before and after the PMCTA procedure, and the similarity degree for each pair was calculated. The means of attenuation increase, quality score, and similarity degree were 53, 31 and 157 HU; 1.6, 1.9 and 1.5; and 67%, 62% and 56% for groups 1,2 and 3 respectively. No histological artifact or impairment was noticed in the histological evaluation of samples collected after PMCTA. Therefore, it can be concluded that histological evaluation can be performed after PMCTA to support the post mortem diagnosis.