Thoracic central venous occlusion from the interventional radiology perspective.

Central venous occlusion is a common condition in certain patient populations, with significant associated morbidity. Symptoms range from mild arm swelling to respiratory distress and can be particularly troublesome in the end stage renal disease population when related to dialysis access and function. Crossing completely occluded vessels is often the most challenging step and various techniques exist to accomplish this. Traditionally, blunt and sharp recanalization techniques are used to cross occluded vessels and are described in detail. Even with experienced providers there are lesions which prove to be too difficult and are refractory to traditional approaches. We discuss advanced techniques such as with radiofrequency guidewires as well as newer technologies which offer an alternative pathway to re-establishing access. These emerging methods have demonstrated procedural success in the majority of cases where traditional techniques were futile. Following recanalization, angioplasty with or without stenting is typically performed and restenosis is a commonly encountered complication. We discuss angioplasty and the emerging use of drug-eluting balloons in venous thrombosis. Subsequently, in regards to stenting we discuss the indications and multitude of available types including novel venous stents with their respective strengths and drawbacks. Potential feared complications such as venous rupture with balloon angioplasty and stent migration are discussed along with our recommendations to reduce their risk of occurrence and promptly manage them when they do unfortunately occur.

Advanced portal venous access techniques for transjugular intrahepatic portosystemic shunt placement.

INTRODUCTION: Transjugular intrahepatic portosystemic shunt (TIPS) placement is a well-established but technically challenging procedure for the management of sequelae of end-stage liver disease. Performed essentially blindly, traditional fluoroscopically guided TIPS placement requires multiple needle passes and prolonged radiation exposure to achieve successful portal venous access, thus increasing procedure time and the risk of periprocedural complications. Several advanced image-guided portal access techniques, including intracardiac echocardiography (ICE)-guided access, cone-beam CT (CBCT)-guided access and wire-targeting access techniques, can serve as alternatives to traditional CO2 portography-based TIPS creation. METHODS: A literature search was performed on the electronic databases including MEDLINE and Embase, from 2000 to the present to identify all relevant studies. The reference list also included studies identified manually, and studies referenced for other purposes. FINDINGS: The main benefit of these advanced access techniques is that they allow the operator to avoid essentially blind portal punctures, and the ability to visualise the target, thus reducing the number of required needle passes. Research has shown that ICE-guided access can decrease the radiation exposure, procedure time and complication rate in patients undergoing TIPS placement. This technique is particularly useful in patients with challenging portal venous anatomy. However, ICE-guided access requires additional equipment and possibly a second operator. Other studies have shown that CBCT-guided access, when compared with traditional fluoroscopy-guided access, provides superior visualisation of the anatomy with similar amount of radiation exposure and procedure time. The wire-targeting technique, on the other hand, appears to offer reductions in procedure time and radiation exposure by enabling real-time guidance. However, this technique necessitates percutaneous injury to the liver parenchyma in order to place the target wire. CONCLUSION: Advanced portal access techniques have certain advantages over the traditional fluoroscopically guided TIPS access. To date, few studies have compared these advanced guided access options, and further research is required.

Lower extremity CT angiography in peripheral arterial disease: from the established approach to evolving technical developments.

With the advent of multidetector computed tomography (CT), CT angiography (CTA) has gained widespread popularity for noninvasive imaging of the arterial vasculature. Peripheral extremity CTA can nowadays be performed rapidly with high spatial resolution and a decreased amount of both intravenous contrast and radiation exposure. In patients with peripheral artery disease (PAD), this technique can be used to delineate the bilateral lower extremity arterial tree and to determine the amount of atherosclerotic disease while differentiating between acute and chronic changes. This article provides an overview of several imaging techniques for PAD, specifically discusses the use of peripheral extremity CTA in patients with PAD, clinical indications, established technical considerations and novel technical developments, and the effect of postprocessing imaging techniques and structured reporting.