A Study on Measurement of Kidney Size by Ultrasonogram and Computerized Tomography

Kim, Soo Hyung; Kwon, Sung Won

Abstract

Though ultrasonogram has many advantages, including no ionizing radiation, the non-invasive character of procedure, the rapidity of study and economy, it is used for complementing modality yet due to the in accuracy of image. Previously in our department of Urology, the report on "A Study on Measurement of Kidney Size by Ultrasonography in Normal Kidney and Hydronephrosis of Korean Adults" had been published. It is an important indicator to measure the renal size and parenchymal depth accurately for indicator of nephrectomy. The author measured the size of the kidney longitudinally, transversely and parenchymal depth by ultrasonogram and computerized tomography (CT) compared with that of excretory urogram in 22 kidneys without hydronephrosis and 15 kidneys with hydronephrosis. In the same method, the kidney was measured by ultrasonogram and CT compared with postoperative specimen in 5 nonvisualized kidneys. The results were obtained as follows 1. Among the 22 kidneys without hydronephrosis, the length and width of the kidney on ultrasonogram (11.2 ( 0.67cm, 5.7( 0,58cm) were very similar to CT (11. 1 ( 0.53cm, 5.5( 0.54 cm) . Among the 9 kidneys with hydronephrosis, the size of the kidney on ultrasonogram were similar to CT 2. Among the 22 kidneys without hydronephrosis, the parenchymal depth of the kidney on ultrasonogram (2.0 ( 0.66cm) was smaller than on CT (2.4 (0.47cm) and the difference was 0.4cm. Among the 9 kidneys with hydronephrosis, the difference was 0.3cm. 3. In comparison with 5 kidneys of the specimen, the length and width of the kidney on ultrasonogram and CT were similar to the specimen. The parenchymal depth of the kidney on CT was similar to the specimen( mean error rate 7 29 (0.18% , correlation coefficient 0.97, P <0.005) but ultrasonogram was much different from the specimen (mean error rate 19.99 ( 6.45% , correlation coefficient 0.94, P <0.005) . By reviewing the above results, CT is more informative and accurate in evaluation of the renal size and parenchymal depth than other modalities, such as excretory urogram or ultrasonogram.