Retroperitoneum
.... Occasionally, however, the sonographer is asked to rule out fluid collection, hematoma, urinoma, or ascitic fluid in the retroperitoneal space. there is no specific patient preparation necessary to image the retroperitoneal cavity, although 6-8 hours of fasting may help to eliminate bowel gas. To image the retroperitoneum, scans should be made in the longitudinal and transverse planes from the diaphragm to the iliac crest, with the patient in a supine or prone position, and from the crest to the symphysis with the patient in a supine position and having a full bladder. The upper abdomen may also be scanned with the patient in a ducubitus position. All scans should include the kidneys and retroperitoneal muscles. Although sonography has proved useful in evaluating soft tissue structures within the abdominal cavity, visualization of the adrenal glands has been difficult because of their small size, medial location, and surrounding perirenal fat. Visualization of the adrenal area depends on several factors: the size of the patient and the amount of perirenal fat surrounding the adrenal area, the presence of bowel gas, and the ability to change the patient into multiple positions. With the patient in the decubitus position the sonographer should attempt to align the kidney and ipsilateral paravertebral vessels. The right adrenal gland has a “comma” or triangular shape in the transaixal plane. . The best visualization is obtained by a transverse scan with the patient in a left lateral decubitus positions. As the patient assumes this positions, the IVC moves forward and the aorta rolls over the crus of the diaphragm to offer a good window to image the upper pole of the right kidney and adrenal gland The longitudinal scan is made through the right lobe of the liver, perpendicular to the linear right crus of the diaphragm. The longitudinal scan is made through the right lobe of the liver, perpendicular to the linear right crus of the diaphragm. The retroperitoneal fat must be recognized as separate from the liver, crus of the diaphragm, adrenal gland, and great vessel. The left adrenal gland is closely related to the left cruss of the diaphragm and the anterior-superior medial aspect of the upper pole of the left kidney. The patient shoul...