What is the significance of increased renal echogenicity on Ultrasound?
Solid organs, such as the liver and spleen, have intermediate echogenicity, and the kidney parenchyma, consisting of the cortex and medulla, is normally isoechoic (equal in brightness) or hypoechoic (darker) compared with the normal liver or normal spleen.
When the right kidney is more echogenic than the normal liver and the left kidney is isoechoic or more echogenic than the normal spleen, the kidneys can be characterized as being abnormally echogenic.
Normal renal cortex is usually hypoechoic (less bright) or sometimes isoechoic (similar brightness) to that of liver or spleen.
Thus, liver and spleen echogenicity must be normal for comparison to be valid; in particular, fatty infiltration of the liver can increase its echogenicity, making evaluation of the echogenicity of the right kidney more difficult.
The normal renal cortex in older infants, children, and adults should be less echogenic than the liver parenchyma.
Only in neonates and infants is increased echogenicity of the renal parenchyma a normal finding.
Increased renal echogenicity is an indication of parenchymal disease but is nonspecific for the type of parenchymal disease, which may include the below
- Acute or chronic glomerulonephritis
- Acute interstitial nephritis
- Diabetes mellitus
- Systemic lupus erythematosus
- HIV nephropathy