D F Smith

CT detection of aortocaval fistula

We describe a patient in whom a secondary aortocaval fistula was diagnosed on dynamic CT by noting transient enhancement of the inferior vena cava simultaneously with maximum enhancement of the aorta. This pattern of caval enhancement is contrasted with the gradual increase and subsequent plateauing of caval opacification seen normally.

Dynamic computed tomography and pulsed Doppler ultrasonography in the evaluation of splenorenal shunt patency.

Dynamic computed tomography (CT) and real-time/pulsed Doppler ultrasonography were performed in 13 patients following a distal end-to-side splenorenal shunt (Warren procedure). The results were correlated with angiography. The anastomotic site was demonstrated by CT in all patients. Coincident enhancement of the distal splenic vein and left renal vein as demonstrated by dynamic CT was an accurate predictor of shunt patency. Ultrasound studies were performed using a transplenic coronal imaging approach. Although the proximal splenic vein and left renal vein could be identified, it was not possible to directly evaluate the anastomotic site in any patients. Dynamic CT evaluation of splenorenal shunts may be a useful technique for monitoring shunt patency during long term follow-up and for evaluating patients who later rebleed.

Compression of the right pulmonary artery by aortic aneurysms: CT demonstration.

Two cases are presented in which compression of the right pulmonary artery by thoracic aortic aneurysm was demonstrated using dynamic CT. The patients initially presented with symptoms suggestive of pulmonary embolus and were found to have unilateral absence of perfusion on isotope lung scan. Computed tomography was useful in demonstrating pulmonary artery compression by aortic aneurysm as the cause in both cases, and in demonstrating an aortic dissection in one case.

Dynamic Computed Tomography and Duplex Ultrasonography: Adjuncts to Arterial Portography

The applications and limitations of contrast enhanced computed tomography (CT) in defining the extrahepatic portal system is discussed in the context of three separate cases in which the CT examination was used as an adjunct to an incomplete arterial portogram examination. Dynamic CT may be useful when excessive contrast dilution precludes the visualization of major venous structures during arterial portography. Real-time/pulsed Doppler ultrasonography is another complementary test but more limited in application than dynamic CT. Patency and flow direction in the proximal splenic vein, portal vein, and hepatic vein can be defined by the ultrasonic technique.