A computer-based technique for measurement of renal parenchymal area on intravenous urograms.

Accurate measurement of the renal parenchymal area of intravenous urograms is discribed using a graphic tablet with a pressure-sensitive surfact linked on-line to a computer. The area outlined on the tablet is immediately computed and shown in square centimetres on a television screen and on a data print-out. The renal areas of 22 patients' urograms were studied before the three months after renal stone removal under local hypothermia. Renal function was measured by creatinine clearance. Conventional measurements of renal length, width and area were also performed for comparison. Results confirmed that while overall kidney size was reduced following operation, the parenchymal area and creatinine clearance were unaltered. This computer-based technique is simple to perform, quick and accurate, and provides quantitative information on intravenous urograms.