The role of ultrasonography in the study of medical nephropathy

Abstract

Diagnostic techniques in nephrology include clinical history, physical examination, laboratory tests, scintigraphy, diagnostic imaging techniques as well as renal biopsy. In kidney diseases, ultrasonography is used as a first-line imaging technique, and its role in medical nephropathy is to exclude urological pathologies, to differentiate between acute and chronic renal failure, to follow-up on the course of a disease, to guide needle biopsy, etc. Ultrasound images are useful at characterizing the pelvis, assessing renal dimensions and parenchymal echogenicity, sampling color-power Doppler signals and evaluating their characteristics and distribution as well as measuring parenchymal resistive index. Taken together, these data can provide useful clues to the diagnosis and help to reduce the number of possible differential diagnoses.

Keywords: Nephropathy; Resistive index; Ultrasonography.

Fig. 1

Kidney: maximum length in a 195 cm tall patient weighing 98 kg.

Fig. 2

Patient undergoing dialysis for about 8 years: kidney of reduced length; poor corticomedullary differentiation, hyperechoic parenchyma and small cysts.

Fig. 3

Kidney: (a) parenchyma appears hypoechoic when compared to the liver parenchyma; (b) parenchyma appears isoechoic when compared to the liver parenchyma; (c) parenchyma appears hyperechoic when compared to the liver parenchyma.

Fig. 4

Medullary sponge kidney: calcifications at the level of the corticomedullary junction with an associated acoustical shadow.

Fig. 5

Hyperechogenicity of the corticomedullary junction; incidental finding in patient with hypertension.

Fig. 6

Diffusely hypoechoic kidney developing lymphoma (courtesy: Carlo Martinoli).

Fig. 7

Patient affected by IDDM: increased intraparenchymal RI (0.85); renal structure and vascularity are normal.

Fig. 8

Left ordinate: RI; x-axis: days; right ordinate: diuresis (ml). Patient with ARF due to interstitial nephritis; intraparenchymal RI values are substantially reduced despite anuria.