LCD L34577: Retroperitoneal Ultrasound

Retroperitoneal ultrasound (US) studies represent the ultrasonic imaging of retroperitoneal organs for the diagnosis and management of abnormalities that occur within the retroperitoneum. A complete retroperitoneal US study visualizes all the structures or organs within the anatomic description of that study. A limited study involves an imaging of only a single quadrant, a single diagnostic problem, or an evaluation of a specific organ of interest. Retroperitoneal ultrasonography may be considered reasonable and necessary for the diagnosis and treatment of the following organs and retroperitoneal structures:

1. Pancreas

2. Abdominal aorta- US is accurate for aortic measurement and may be used to follow patients with aortic aneurysms.

3. Inferior vena cava - US is useful in the detection of invasion by adjacent tumors and identification of obstruction levels.

4. Kidneys, ureter, and bladder:

a) Kidneys-

i) May confirm scarred or small kidneys in chronic renal cortical disease (but may be of no use in detecting early or mild cortical disorders or to categorize specific types of cortical diseases).

ii) May be useful in detecting and following renal cysts and localizing solid masses.

iii) May be useful as a primary diagnostic tool in patients with suspected renal disease.

b) Ureter- Normal ureters are usually not well visualized by US, especially in their mid-portions. Renal US is the primary mode of diagnosis of a renal obstruction which is demonstrated by dilated ureters. It may be helpful in identifying filling defects or a mass, in its most proximal or distal portions. US has no role in vesicular ureteral reflux.

c) Bladder- Tumors of the bladder are most efficiently followed by cystoscopy and urography. However, US is useful in following intraluminal bladder tumors with or without extraluminal extension, including evaluation of bladder wall thickness and irregularity and evaluating post void residual at the bedside.

5. Renal transplants- US is indicated to detect urinary obstruction, fluid collection, and complications of renal transplants and is considered a primary tool in this endeavor. The presence or absence of signs and symptoms dictate utilization frequency of this modality for renal transplants.

6. Adenopathy- Computed tomography (CT) is far more accurate than US in detecting and delineating adenopathy. US in this instance should be considered secondary and rarely utilized in the detection or follow up of nodal disease.

7. Prostate- Evaluation of the prostate is primarily done transrectally by US.

8. Adrenal Gland- US is of little value since a CT scan is considered more accurate.

9. Organs located in the retroperitoneal region- US may be helpful in the evaluation of wounds, contusions, and lacerations of organs located in the retroperitoneal region.

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