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Despite inferior vena cava (IVC) filter practice spanning over 50 years, interventionalists face many controversies in proper utilization and management. This article reviews recent literature and offers opinions on filter practices. IVC filtration is most likely to benefit patients at high risk of iatrogenic pulmonary embolus during endovenous intervention. Filters should be used selectively in patients with acute trauma or undergoing bariatric surgery. Retrieval should be attempted for perforating filter and fractured filter fragments when imaging suggests feasibility and favorable risk-to-benefit ratio. Antibiotic prophylaxis should be considered when removing filters with confirmed gastrointestinal penetration. Anticoagulation solely because of filter presence is not recommended except in patients with active malignancy. Anticoagulation while filters remain in place may decrease long-term filter complications in these patients. Patients with a filter and symptomatic IVC occlusion should be offered filter removal and IVC reconstruction. Physicians implanting filters may maximize retrieval by maintaining physician-patient relationships and scheduling follow-up at time of placement. Annual follow-up allows continued evaluation for removal or replacement appropriateness. Advanced retrieval techniques increase retrieval rates but require caution. Select cases may require referral to experienced centers with additional retrieval resources. The views expressed should help guide clinical practice, future innovation, and research.

In 1998, the American Board of Radiology introduced the B. Leonard Holman Research Pathway (HRP) to initial certification for trainees in diagnostic radiology (DR) and radiation oncology (RO) motivated to pursue research-oriented careers in academic DR and RO.The HRP Committee anticipated that there would be a relatively even distribution between DR and RO participants, but with 18 years of experience that has not been the case. This article focuses on the HRP and DR.

OBJECTIVE. Transjugular intrahepatic portosystemic shunt (TIPS) creation increases the risk of hepatic encephalopathy due to overshunting. Techniques exist to secondarily reduce the shunt for refractory encephalopathy. The purpose of this article is to describe a technique for primary TIPS restriction using a balloon-expandable stent within the transvenous hepatic track followed by deployment of a self-expanding polytetrafluoroethylene–lined stent-graft within the balloon-expandable stent to create the TIPS. CONCLUSION. This technique enables control over the degree of portosystemic shunting in elective TIPS creation.

The purpose of this study was to describe the variable anatomy of mesenteric veins on axial CT images and on volume-rendered CT venograms that use maximum intensity projection and shaded-surface display.Fifty-seven patients undergoing helical CT of the pancreas were included in the study. The mesenteric venous system was analyzed in 54 patients. Three patients were excluded because the helical CT data were unsatisfactory.On helical CT with maximum intensity projection and shaded-surface display, the superior mesenteric vein (SMV) was seen as a single trunk of variable length in 40 patients. In seven other patients, two mesenteric trunks merged separately with the splenic vein. In the remaining seven patients, the SMV was occluded by tumor. The inferior mesenteric vein drained into the splenic vein in 28 patients (56%), into the SMV in 14 patients (26%), and into the splenomesenteric angle in nine patients (18%).Both axial and volume-rendered CT venograms accurately reveal the variable mesenteric venous anatomy. CT venograms may replace conventional angiography in presurgical planning.

We compared peripheral vascular MR angiography done with a standard transmit-receive head coil with conventional arteriography for identifying and evaluating runoff vessels below the knee.We examined 55 legs in 31 symptomatic patients with both conventional contrast angiography and gradient-echo two-dimensional time-of-flight MR angiography. Both legs of patients were placed in a standard transmit-receive head coil for MR angiography and were imaged simultaneously. For evaluation of stenoses, images of vessels were divided into 10 segments, and each segment was graded on a four-point scale.In the 393 native vascular segments evaluated, the sensitivity of MR angiography in identifying normal vessels was 95% and the specificity was 98%. In detecting segmental occlusion, MR angiography was 98% sensitive and 97% specific. Sensitivity and specificity for stenoses greater than 75% were 98% and 96%, respectively, and for stenoses greater than 50%, they were 98% and 95%, respectively. Interpretative discrepancies were found in 35 vessel segments in 18 legs; none was of clinical relevance. Of all vessel segments shown as occluded by conventional angiography, 1% appeared patent on MR angiograms. No vessel segments shown as normal on MR angiograms were found to be occluded on conventional angiograms.When performed simultaneously on both legs of symptomatic patients, 2D time-of-flight MR angiography with a standard transmit-receive head coil provides a time-efficient and highly sensitive and specific means of evaluating below-knee runoff.

The purpose of this study were to quantify abdominal vascular enhancement and to prove the feasibility of iron oxide-enhanced MR angiography in humans using three doses of superparamagnetic iron oxide agent AMI 227.Sixteen patients randomly received either 0.8, 1.1, or 1.7 mg Fe/kg of ultrasmall superparamagnetic iron oxide agent AMI 227. T1-weighted breath-hold gradient-echo images were obtained before and 45 min after i.v. administration of AMI 227. Signal intensity was measured in the aorta, the inferior vena cava, the portal vein, and muscle on unenhanced and contrast-enhanced images. Signal-to-noise ratios and enhancement [(SNR after contrast-SNR before contrast) / SNR before contrast] were calculated. Vessels were visually graded before and after administration of AMI 227.All vessels showed statistically significant enhancement 45 min. after administration of AMI 227 by both qualitative and quantitative measures (p.001). There was no significant increase in noise or signal intensity of muscle after contrast material was administered. The amount of enhancement was not statistically significantly different among the three doses.AMI 227, which is currently in phase III clinical trials, demonstrates significant vascular enhancement and may prove useful as an MR angiographic contrast agent.

The purpose of this study was to evaluate the ability of echoplanar MR angiography to depict the major hepatic and portal venous structures.Echoplanar and conventional MR angiographic examinations were performed in 10 subjects (seven healthy volunteers, three patients with focal hepatic lesions). A gradient-recalled echo (GRE) time-of-flight technique (125/10 [TR/TE], 90 degrees flip angle) was used for echoplanar angiography. Eight complete single-excitation images were acquired at each level in 1.5 sec and then collapsed into a single maximal intensity projection. Conventional time-of-flight MR angiography (34/13, 30 degrees flip angle) also was performed. The vascular anatomy from the right atrium to the splenic vein was imaged (6-mm contiguous levels) in three 10.5-sec breath-holds with echoplanar imaging, as compared with seven 11.5-sec breath-holds with conventional MR angiography. Echoplanar and conventional images were compared quantitatively and qualitatively.Echoplanar imaging was 61% faster than conventional MR angiography. Vessel-to-liver signal-intensity ratios were significantly higher for echoplanar imaging (p.0001), signal-to-noise ratios were significantly higher for conventional MR angiography (p.0001), and contrast-to-noise ratios were comparable. Qualitatively, echoplanar imaging and conventional MR angiography provided similar anatomic information about the hepatic and portal veins.Angiograms of the hepatic and portal venous systems that are of diagnostic quality can be acquired much more quickly with echoplanar imaging than with conventional MR angiography.

T he tnansjugulan intrahepatic portosystemic shunt (TIPS) has become an accepted therapy for many patients with end-stage liver disease and portal hypertension. Indications include vaniceal bleeding, intractable ascites, and some forms of the Budd-Chiani syndrome [1-3]. Generally accepted contraindications to TIPS include portal vein occlusion, polycystic liver disease (PCLD), right heart failure, severe hepatic failure, or severe encephalopathy [1-3]. For unclear reasons, PCLD has been cited as a relative and absolute contraindication to TIPS [ 1-3]. The presence of multiple large cysts may distort the hepatic parenchyma and vasculature and can make creation of the TIPS parenchymal tract difficult. This case report summarizes the creation of a TIPS in a patient with PCLD and refractory ascites.

Long-term central venous access usually is achieved by placing a catheter into the superior vena cava through the upper extremity orjugular veins [1 , 2]. Alternative percutaneous approaches to the central veins are required when the subclavian and brachiocephalic veins no longer are available due to thrombosis related to instrumentation and hypercoagulable states [1]. These alternative approaches include translumbar puncture of the infrarenal inferior vena cava (IVC), transhepatic cannulation of the hepatic veins or intrahepatic IVC, and femoral venous catheterization [1-3]. The use of intercostal veins as alternative conduits for placing central venous catheters previously has required a surgical procedure [4-7]. In this article,we describe the cannulation of an intercostal vein via the basilic vein for placement of a long-term central venous access catheten in a patient with occlusion of the subclavian veins, brachiocephalic veins, and proximal superior vena cava.

Vascular and interventional radiology , Vascular and interventional radiology , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی