Findings
The kidney is enlarged with inhomogenous echotexture and loss of corticomedullary differentiation.
Discussion
The edema associated with acute bacterial pyelonephritis causes the ultrasound findings described above. There is a differential for this ultrasonic appearance which includes other infiltrative processes. The patient’s clinical presentation added to the ultrasound findings makes the diagnosis of acute bacterial pyelonephritis.


http://eradiology.bidmc.harvard.edu/Classics/item.aspx?section=Emergency+Radiology&labelpk=33f0adab-853f-4010-a0e2-0756b3f1eac5&pk=7ac826e1-55cb-4fff-b7b3-176c3d38ff41

Findings
There are multiple wedge-shaped low-attenuation areas in the left kidney.
Discussion
Wedge-shaped, low attenuation areas may be seen with acute bacterial pyelonephritis or multiple renal infarcts. Location of the wedges in line with the calyces suggests pyelonephritis, wedges located between calyces suggest infarcts. The patient’s clinical presentation also assists in this differential. Complications of the pyelonephritis include renal and perinephric abscess formation, emphysematous pyelonephritis, and pyohydronephrosis.


http://eradiology.bidmc.harvard.edu/Classics/item.aspx?section=Emergency+Radiology&labelpk=33f0adab-853f-4010-a0e2-0756b3f1eac5&pk=2e0ab04c-0ce0-446d-bb66-81cd5083a997

arrows=focal heterogenous lesion

thickening of fascia.

swelling of right kidney.