A patient treated for acute pyelonephritis 10 days ago presents with persistent flank pain and leukocytosis. Ultrasound demonstrates a thick-walled fluid collection with internal septations and echoes located between the renal capsule and Gerota’s fascia. What focal infectious fluid collection has developed as a complication of this disease process?

Which of the following conditions represents a prerenal cause of acute renal failure?

Pheochromocytoma is a tumor of the adrenal medulla and causes traces of urinary epinephrine and norepinephrine following attacks.

A sonographer visualizes a fluid-filled cavity situated outside the renal parenchyma beyond the medial border of the renal hilum. The infundibula and calyces within the renal sinus show no dilation. What normal variant does this most likely represent?

This 68 year old male was referred to the ultrasound department for an abdominal exam. His history is significant for unexplained fever and recent gross hematuria. What pathological process is demonstrated in the pelvic portion of this longitudinal kidney image?

Hydronephrosis on ultrasound most classically appears as

Regarding adrenal gland position and shape:

A 26-year-old female presents with recurrent nephrolithiasis and dysuria. Ultrasound of the kidneys reveals bright, highly echogenic medullary pyramids bilaterally. The renal cortex appears normal. What congenital dysplastic disorder is represented by this appearance?

A three year old child presents with a palpable mass in the RUQ, has an enlarged liver, weight loss, vomiting, hypertension and abdominal pain. The lab tests show anemia and elevated urinary catecholamines. The sonogram demonstrates a large solid mass with a mixed echo pattern. This most likely represents a:

Pyonephrosis is best suggested by