No abstract

The authors studied seven patients with penetrating aortic ulcers with use of magnetic resonance (MR) imaging. All patients were evaluated for acute chest symptoms, and the presence of aortic ulcers was confirmed by means of angiography in all seven patients. Five patients also underwent computed tomography (CT). Three patients underwent surgical repair of the thoracic aorta. MR findings included intramural hematoma and focal aortic wall ulceration in four patients, focal ulceration in one, focal intramural hematoma in one, and focal intramural hematoma with rupture in one. The diagnosis of intramural hematoma was made by the detection of increased signal intensity on T1- and T2-weighted MR images. MR imaging was superior to angiography in depicting the extent of intramural thrombus, although one ulceration diagnosed at angiography was missed at MR imaging. MR imaging was superior to CT in differentiating acute intramural hematoma from atherosclerotic plaque and chronic intraluminal thrombus, although it did not depict displaced intimal calcification in one patient with extensive intramural hematoma.

Four patients with intrahepatic arterial aneurysms were treated with transcatheter embolization. Two patients had multiple aneurysms, and two had single aneurysms; in two the aneurysms were post-traumatic, and in the other two they were mycotic. Either Gelfoam or isobutyl-2-cyanocrylate was used to occlude the hepatic artery branches. It is concluded that transcatheter embolization is a safe and effective method for the management of these aneurysms and can be used as an alternative to surgery.

Using a flow model that simulated the inferior vena cava (IVC), the authors conducted an in vitro comparison of the Mobin-Uddin (MU), Kimray-Greenfield (KG), Amplatz spider (A), Günther basket (G), Simon nitinol (SN), and bird's nest (BN) filters. The following parameters were evaluated: clot-trapping capacity and flow dynamics, which included measurements of pressure gradients across filters and assessment of flow patterns. The MU, A, G, SN, and BN filters trapped an average of 80%-100% of small clots and 100% of large clots. The KG filter, in a central position, trapped 0%-10% of small clots and 60%-100% of larger clots. In the eccentric position, the KG filter trapped only 20% of all clots. The BN and SN filters showed the least flow turbulence. Moderate turbulence was observed with the G and KG filters, while the MU and A filters showed marked turbulence. The current standard KG filter allowed the passage of small and large clots. When specific parameters were considered--such as clot-trapping capacity and flow-dynamic performance--the BN, SN, and G IVC filters were superior to the other filters that were tested.

The Simon nitinol filter for percutaneous interruption of the vena cava to prevent pulmonary embolism is currently undergoing a multicenter clinical trial. Preliminary clinical results are reported as work in progress. The results in 44 patients at two centers are analyzed in detail, and major events are reported from 103 patients in 17 centers in the United States during a 10-month period. The filter was successfully inserted via the femoral or jugular route in all patients through a 9-F catheter. The placement procedure was easy and without significant complications. Follow-up studies included plain radiography, ultrasonography, magnetic resonance (MR) imaging, and clinical evaluation. No filter migration or perforation occurred among the 103 patients. Symptomatic occlusions occurred in 7%-9%, comparable to other series, and some asymptomatic occlusions were detected with MR imaging only. The implications of occlusion of the filter are discussed.