SU‐E‐I‐17: Micro CT Analysis of Results of Protein Deficiency On Rat Offspring

Purpose: To evaluate the use of image based metrics in the study of renal vascular development in offspring from low protein fed pregnant rats. Methods: Using a custom, self made micro CT imaging system, we imaged two groups of rat kidneys. The control group consisted of eight one year old Wistar rat offspring exposed to normal maternal rat diet during pregnancy. The second group, of the same breed and age, were eight offspring of a low protein maternal diet during pregnancy. Both groups were euthanized and a warm barium sulfate gelatin suspension was pressure infused into the arterial circulation, creating radio opacity for identification of the arterial vasculature. Approximately one hour after administration, the kidneys were harvested, placed in formalin, then stored at 4°C. Each kidney was imaged using our micro CT machine set from 47 to 55 kVp and 40 to 60 Watts. Results: Clearly the renal vasculature development differed greatly between the two groups. In particular, the protein deficient group developed segmental renal arteries with larger diameters. There was also a minimal difference in the percentage of arteries to tissue volume for the two groups. After examining the 3D reconstructions, we set gray level threshold values for vasculature and for tissue. We then determined the corresponding volumes and volume ratio using LabView. Utilizing the projection images, we also measured the diameter of three vessels near the hilum of the kidney, segmental arteries. On average, the control group and protein deficient artery diameters were 375.71±49.10 516.33±52.58 μm, respectively. A comparison of histograms of the vessel diameters demonstrated a minimally overlapping classification of the two groups of animals. Conclusion: Using our custom made Micro CT scanner images, we were able to quantify the physiological effect of a maternal protein deficient diet on the developmental morphology of the offspring kidney vasculature. Support: NIH Grant 2R01EB002873.