A Study on Measurement of Kidney Size by Ultrasonography in Normal Kidney and Hydronephrosis of Korean Adults

Ko, Joung Wan; Kwon, Sung Won

Abstract

Advances in gray scale ultrasonography have increased the usefulness of their modality in the clinical diagnostic method. Major improvements in the image resolution have greatly increased the diagnostic value of renal ultrasonography. The non-invasive and safe nature of ultrasound makes this technique ideal for accurate and quick evaluation. It has been well known facts that it is very difficult to obtain precise size, shape parenchymal thickness of the kidneys by conventional radiological techniques such as retrograde pyelography, antegrade percutaneous pyelography or arteriography and also the techniques are invasive to patients comparatively. Because of its simplicity, innocuousness and accurateness, diagnostic ultrasound is quite useful in the evaluation of functionally inactive kidney and should precede or be substitute for other aggressive technique. In those kidneys which remain unseen even after massive dose of dye, the ultrasound scan should be used before retrograde ureteral catheterization is undertaken. The author measured the size of kidney longitudinally, transversely and in thickness by ultrasonogram and compared with that of excretory urogram in 60 normal healthy persons and 32 cases of hydronephrosis. The results were obtained as follows: 1. The length of right kidney on ultrasonogram (11.4+/-0.55 cm) was smaller than on excretory urogram (12.2+/-0.45 cm) and the difference was 0.8 cm (t value: 2.21, p<0.02), and the length of left kidney on ultrasonogram (11.9+/-0.42 cm) was smaller than on excretory urogram (12.6+/-0.78 cm) and the difference was 0.7 cm (t value: 2.43. p<0.02). The width of right kidney on ultrasonogram (5.4+/-0.57 cm) was smaller than on excretory urogram (6.3+/-0.61 cm) and the difference was 0.9 cm (t value: 1.75, p<0.1) and the width of left kidney on ultrasonogram (5.6+/-0.58 cm) was smaller than on excretory urogram (6.3+/-0.49 cm) and the difference was 0.7 cm (t value: 1.82, p<0.1). The parenchymal depth of right kidney on ultrasonogram (2.2+/-0.48 cm) was larger than on excretory urogram (2.1+/-0.56 cm) and the difference was 0.1 cm (t value: 2.89, p<0.001), and the parenchymal depth of left kidney on ultrasonogram (2.1+/-0.54 cm) was alike on excretory urogram (2.1+/-0.57 cm) and there was no difference (t value: 2.31, p<0.05). 2. Among the 32 cases of hydronephrosis. 17 cases of hydronephrosis could be diagnosed by excretory urogram. In mild hydronephrosis, the length of kidney on ultrasonogram (12.2+/-0.56 cm) was smaller than on excretory urogram (12.8+/-0.46 cm) and the difference was 0.6 cm, the width of kidney on ultrasonogram (6.1+/-0.27 cm) was smaller than on excretory urogram (6.4+/-0.38 cm) and the difference was 0.3 cm, and the parenchymal depth of kidney on ultrasonogram (2.1+/-0.34 cm) was alike on excretory urogram (2.1+/-0.49 cm) and there no difference. In moderate hydronephrosis, the length of kidney on ultrasonogram(13.5+/-0.47 cm) was smaller than on excretory urogram(14.2+/-0.67 cm)and the difference was 0.7cm, the width of kidneys no ultrasonogram(7.2+/-0.58 cm) was smaller than on excretory urogram(7.8+/-0.73 cm) and the difference was 0.6cm, and the parenchymal depth of kidney on ultrasonogram(1.2+/-0.57 cm) was smaller than on excretory urogram(1.47+/-0.27 cm)and the difference was 0.2 cm. In severe hydronephrosis, the length of kidney on ultrasonogram(15.7+/-0.39 cm)was smaller than on excretory urogram(16.6+/-0.53 cm) and the difference was 0.9cm, the width of kidney on ultrasonogram(8.8+/-0.46 cm) was smaller than on excretory urogram(9.5+/-0.48 cm)and the difference was 0.7 cm, and the parenchymal depth of kidney on ultrasonogram was 0.7+/-0.27 cm but could not be measured on excretory urogram. 3. Among 32 cases of hydronephrosis,15 cases of hydronephrosis were non-visualized kidney on excretory urogram. On them, the renal sized and parenchymal depth were measured accurately by ultrasonography. By reviewing the above results, the ultrasonography of kidney is useful in measurement of kidney size and can be substitute for invasive uroradiological methods in evaluation of patients with hydronephrosis.