Assessment of photoacoustic computed tomography to classify tissue in a polycystic-kidney disease mouse model

Purpose: The purpose of this study is to evaluate PCT Imaging technique to classify tissue and extract kidney cysts in pcy mice model of human adolescent nephronophthisis. Method: Four mice with late stages of nephronoplithisis with polycystic kidney disease-PKD and one normal mouse were scanned in the PCT Small Animal Scanner. Both vivo and ex-vivo images of mice kidney were taken at wavelength from 680 nm to 940 nm. The ex-vivo PCT images were compared with histology photographs to check the sensitivity of detecting cysts. Histograms of kidney images were generated over slices and fitted to Gaussian-curve model for volumetric analysis. The portions of cysts in kidneys were estimated and kidney images were segmented by three different colors to present the distribution of different tissues. Result: A good correspondence between PCT imaging findings and PKD histology result was observed. Histogram curves from images of pcy kidneys and normal kidneys were fitted to Gaussian-curve model. Portions of cysts, parenchyma and area of high level hemoglobin were estimated according to the curve fit result. A growth of cysts associated with relatively volume decrease of parenchyma and tissues with high perfusion of hemoglobin was observed. Conclusion: The PCT enabled visualization of renal cysts for mouse model and had the potential for volumetric measurements of kidney.