Hydronephrosis

This week's images were submitted by Drs. Akther and Pitts. They demonstrate various degrees of hydronephrosis. To obtain these images in the coronal plane, place the probe into the same position that you use to obtain a view of the left/right kidney during your fast exam. You may need to slide the probe more inferiorly towards the feet to focus on the kidney.  Rotate the probe 90 degrees to the see the organ in the short axis.

The first image represents a normal kidney with a hyperechoic (bright white) renal sinus and a hypoechoic (darker then surrounding tissue) cortex. 

The next image represents a “well hydrated” patient and shows prominence of the renal medullary pyramids which are anechoic. Do not confuse a well hydrated patient for hydronephrosis (the renal sinus remains hyperechoic in hydrated patients with prominent pyramids.)  

The third image shows moderate hydronephrosis, where large anechoic (black) areas representing urine can be seen within the echogenic renal sinus.  

The fourth image shows severe hydronephrosis, a term reserved for kidneys with cortical thinning which disrupts the normal architecture of the kidney.

This is a schematic diagram from http://www.med.cornell.edu that reinforces the idea of the gradual dilatation that the renal calyces undergo in hydronephrosis. 

Please note that as emergency sonographers, we only distinguish between normal kidney, moderate, and severe hydronephrosis.