All correlations significant at the 0.01 level. TPA and TPV in the carotid stenosis population were normally distributed. Inspection for skewness and kurtosis revealed significantly non-normal distributions for IMT, TPA and TPV in the diabetic nephropathy population. These variables were transformed to produce distributions that did not deviate significantly from normal. Inverse transformation was used for IMT (1/IMT) and cube root transformation was used for area and volume measurements (TPA1/3 and TPV1/3).