POCUS Gallery

POCUS = Point-of-Case Ultrasound
POCUN = Point-of-Care Ultrasound in Nephrology
RFN Focus on POCUN Series 


Kidney

Kidney

Normal Kidney. The echogenic capsule makes the bean shaped organ easily identifiable. The cortex is either isoechoic or hypoechoic (more commonly) compared with the normal liver or normal spleen. The medullary pyramids are hypoechoic or anechoic compared to cortex. On most occasions, the pyramidal shape is not well visualized. The renal cortical tissue extends into the medulla, separating pyramids in the form of columns called ‘columns of Bertin’. Renal sinus fat is echogenic and occupies major part of the inner kidney. The collecting system is usually not visualized unless distended and is embedded in the surrounding echogenic sinus fat. The renal pelvis area is hypoechoic but not “black” unless there is hydronephrosis. Similarly, ureters are not seen unless distended (hydroureter).
Normal Kidney. Sagittal and transverse views, liver on the right and spleen on the left.
Normal Urinary Bladder.  It appears as an anechoic fluid-filled structure (urine is black on ultrasound) located in the mid pelvis. A full bladder is necessary to comprehensively evaluate the characteristics of its walls, contents and pelvic organs. The sagittal view is triangular and transverse section is rectangular – but the shape varies depending on bladder fullness.
Kidney Stones. On grey scale image, stones appear as hyperechoic or bright structures with a posterior “acoustic shadow.” Acoustic shadowing is the black or anechoic area seen beyond structures that do not transmit ultrasound waves. In the Doppler view (inset), stones exhibit a “twinkling sign” or artifact – rapidly alternating focus of color Doppler signals mimicking turbulent flow . This artifact is more pronounced with rougher stones, and more sensitive than shadowing for detection of small stones.
Cysts. A. Simple cyst: well-defined, round, anechoic structure. Increased through transmission manifested by “acoustic enhancement”, which refers to the increased intensity of echoes (bright area) relative to surrounding tissues, distal to a structure that transmits the sound waves very well. B. Large kidney with multiple cysts, seen in Autosomal dominant polycystic kidney disease. C. Complex cyst with internal septations.
Hydronephrosis. A. Mild hydronephrosis: dilatation of the renal pelvis and calyces with preserved pelvicalyceal pattern. Cortico-medullary differentiation is preserved and we can see the pyramids. B. Moderate hydronephrosis: As the severity of hydronephrosis increases, urine moves proximally into the kidney exerting pressure on the parenchyma. There is increasing dilatation of the renal pelvis and urine extending inside the kidney. The convex irregular border of the collecting system at the top mimics a “cauliflower appearance.” C. Severe hydronephrosis: renal pelvis and calyces appear ballooned and cortico-medullary differentiation is lost, making the cortex thin. The kidney looks like a fluid filled bag.

Contributors: Abhilash Koratala, MD, FASN (@NephroP)