Because of an overly large contribution from large clustered and exophytic cysts in the mid-slices, the cyst volumes (right 1028.0 mL, left 1067.3 mL) predicted from the product of the mid-slice cyst area measurement (right 36.0 cm2, left 45.0 cm2) and the number of slices (right 44, left 37) greatly exceeded the observed cyst volumes (right 362.0 mL, left 378.6 mL) that were measured by summing all the slices covering the whole kidney. The multiplier to the cyst area product used to predict the volume was 0.637 for the right and 0.608 for the left kidney.