The use of dilute Calogen as a fat density oral contrast medium in upper abdominal computed tomography, compared with the use of water and positive oral contrast media.

AIM: Oral contrast media are commonly given prior to computed tomography (CT) examination of the upper abdomen. Although positive oral contrast media are normally used, there is increasing interest in using negative agents such as water and less commonly fat density products. The aim of this study was to compare a positive oral contrast medium, water, and a diluted emulsion of arachis oil Calogen, a fat density food supplement) for assessment of the upper abdomen. MATERIALS AND METHODS: Seventy-one patients referred for upper abdominal CT were randomized to receive either 500 ml water, 2% sodium diatrizoate or a dilute suspension of Calogen. The CT images were scored independently by three radiologists. Distension and anatomical identification was assessed for the stomach, duodenum and jejunum; with anatomical identification recorded for the pancreas, retroperitoneum, liver, gallbladder and spleen. RESULTS: Dilute Calogen produced a significant improvement (P < 0.01) in distension and anatomical visualization of the stomach and proximal duodenum. Only minimal differences were demonstrated between the three contrast media for visualization of more distal small bowel or identification of the other upper abdominal viscera. Significantly more artifacts were caused by positive contrast media than with the Calogen mixture. CONCLUSION: A dilute suspension of Calogen as an oral contrast medium is recommended when disease is suspected within the stomach or proximal duodenum.

Bowel lesions: percutaneous US-guided 18-gauge needle biopsy--preliminary experience.

Ultrasonography-guided percutaneous biopsy was performed with local anesthesia and an 18-gauge needle in 10 patients with bowel-wall lesions. All patients underwent clinical review within 1 month. Biopsy was diagnostic in all patients. There were no complications, and all patients tolerated the procedure well. The technique appears to be safe and had an excellent diagnostic yield in our series.

A negative herniogram does not exclude the presence of a hernia.

A retrospective review of 63 consecutive herniograms over a 3-year period was performed to assess the reliability in diagnosis of occult hernias. In all, 26 hernias were diagnosed in 23 patients, of which 13 were confirmed at operation. However, there were three false-positive results. Of the 38 negative herniograms, four proceeded to surgery with three positive hernia findings. We therefore found false-positive and false-negative rates of 18.7% and 7.9%, respectively. All of the false-positive results were in patients with a history of pain as the presenting complaint, while all of the patients with false-negative results had presented with a history of both pain and jump but no clinically detectable hernia. Our experience of this investigation is not as encouraging as others have reported.

Dynamic contrast-enhanced MR imaging of the portal venous system: comparison with x-ray angiography.

PURPOSE: To compare dynamic contrast material--enhanced multisection magnetic resonance (MR) imaging with x-ray angiography in the evaluation of the portal venous system. MATERIALS AND METHODS: Eighteen patients underwent preoperative x-ray angiography and dynamic contrast-enhanced MR imaging. MR imaging was performed at 1.0 T with a multisection breath-hold fast low-angle shot (FLASH) technique in the coronal-oblique plane, before and after injection of a bolus of gadopentetate dimeglumine. The portal vein, its right and left intrahepatic branches, the splenic veins, and the superior mesenteric veins were examined. The presence of varices was also assessed. RESULTS: Of the 84 vessels evaluated with both techniques, appearances were similar in 76 (90%). Both examinations showed the main portal vein to be patent in nine patients, occluded in five, and patent but abnormal in two. Findings in the main portal vein were discordant in two patients. In one patient, surgical follow-up helped confirm the findings at MR imaging. CONCLUSION: MR imaging can replace x-ray angiography in the preoperative evaluation of portal vein patency in most patients.

Intrarenal Doppler ultrasound studies in normal and acutely obstructed kidneys.

Renal ultrasound examinations and intrarenal arterial Doppler studies were performed on 48 patients with normal renal tracts and 20 patients presenting with acute renal colic resulting from ureteric calculus, 14 of whom had urographic evidence of renal obstruction. The mean resistance index (RI) of the Doppler waveforms obtained on the 14 obstructed kidneys (70.4 +/- 6.22) was significantly higher than the mean RI of the 96 normal kidneys (62.4 +/- 6.43). The mean difference between the RIs of the obstructed kidneys and their contralateral non-obstructed kidneys (8.37 +/- 4.43) was also significantly higher than the differences in RI seen between pairs of normal kidneys (2.70 +/- 1.71). Five out of 14 obstructed kidneys showed no pelvicalyceal dilatation and could not have been shown to be obstructed on conventional sonography. Four of these five had RI changes suggestive of obstruction and thus 13 of 14 obstructed kidneys would have been identified as obstructed by a combination of Doppler and conventional sonographic findings. 10 of the 14 obstructed kidneys were re-examined after passage of a urinary calculus and nine showed a reduction in the RI of the previously obstructed kidneys. The 10th subsequently required ureterolithotomy.