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On transverse ultrasound scans a small number of patients with a paucity of retroperitoneal fat show an initial false impression of a left renal artery aneurysm due to the confluence of two normal findings. The left renal vein is unusually prominent from the hilum of the left kidney to the area between the superior mesenteric artery and the aorta; and part of the normal aortic wall, adjacent to the left renal vein, is incompletely imaged. Explanations for the prominence in the left renal vein and the partial visualization of the aortic wall are discussed, and various maneuvers that allow for accurate identification of both are described. The use of this analysis should prevent the incorrect diagnosis of a left renal artery aneurysm, which might lead to more invasive diagnostic procedures.

The ultrasonic characteristics of bilomas are reviewed in five patients, one of whom was also studied with computed x-ray tomography. Certain features not previously reported should aid in differentiating bilomas from other intra-abdominal fluid collections.

A new technique is described for delineating pelvic structures by using a distended bladder in combination with a water enema. The distended urinary bladder, which acts as a sonic window to the pelvis, fully defines only the portion of structures that abut against the surface. With fluid in both the bladder and rectosigmoid colon, and occasionally the cecum, a ‘sandwich effect’ can be obtained, resulting in a more complete definition of interposed structures. Questionable masses that might be feces in the bowel can be easily distinguished from significant pathology. This new technique has the potential for increasing accuracy of diagnosis of pelvic masses and delineating tumor extension of masses arising in such pelvic organs as the bladder, prostate, and uterus.

Three cases of renal agenesis are presented, representing the spectrum of abnormality seen in utero. Severe oligohydramnios was seen in all three cases. In two cases ultrasound demonstrated fetal paraspinal structures resembling kidneys, while in the third no renal shapes were identified. The urinary bladder could not be imaged in any of the cases. Autopsy findings demonstrated that the reniform structures represented only fetal adrenal glands of varying sizes. It is suggested that the examination of the renal tract in severe oligohydramnios should be directed toward the fetal urinary bladder, because the identification of reniform outlines can be misleading.

In vitro and in vivo experience with a real-time aspiration-biopsy transducer indicates that the advantage of this instrument is that it permits the examiner to monitor the movement of the structure being aspirated or biopsied, as well as the movements of adjacent organs, while the needle tip is being inserted into the structure. When the needle tip is inserted into the skin, a strong acoustic shadow is produced along the path of the needle, indicating the optimum position for aspiration and biopsy. Within fluid-filled areas the needle tip is imaged consistently. For solid-organ biopsies, the movement of the structure of interest as well as the acoustic-shadow path of the needle can be consistently observed, but the needle tip is recorded with more difficulty.