Automated Measurement of Stone Heterogeneity Index and Variation Coefficient of Stone Density on CT Image

Abstract

Heterogeneity is a key feature of stone density as Hounsfield Unit (HU) on computer tomography (CT) for extracorporeal shock-wave lithotripsy (ESWL) outcomes predicting in urinary calculi patients. The goal of this study is to develop the modified 2D and 3D automate stone heterogeneity index and variation coefficient of stone density estimation program to predict ESWL treatment. For 2D, the proposed program was selected the largest slice of the stone in the whole input slice and then stone related variables, stone heterogeneity index and variation coefficient of stone density were calculated by using the average HU and the number of voxels of the stone. For these variables, it was also developed 3D automate system by using all slices including the stone. Moreover, the 2D schematic diagram was produced to show the internal structure of stone in order to estimate the compositional heterogeneity of stone. All processes of this study were established without manual process. And then, the result of the proposed study is presented compared with the manual measurements. The described methods can provide to assist the prediction of ESWL treatment success and urinary stone diagnosis.