What is the role of imaging studies in the preprocedure assessment for inferior vena cava (IVC) filter placement?

Updated: Oct 31, 2020
  • Author: Gary P Siskin, MD; Chief Editor: Kyung J Cho, MD, FACR, FSIR  more...
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Answer

Answer

The caliber of the IVC varies in accordance with the intravascular volume, the phases of respiration, and cardiac function. The mean diameter of the IVC is 19-20 mm; approximately 3% of patients have a megacava, in which the diameter is greater than 28 mm.

Imaging and cavography have been used to visualize the IVC for its size, its configuration, and any anatomic variation. Imaging is also used to evaluate the presence and extent of bland and tumor thrombus within the IVC.

Ultrasonography

The usefulness of US sometimes can be limited by overlying bowel gas and a large body habitus. This imaging modality is used more commonly in the evaluation of the common femoral veins or the internal jugular veins to assess patency before puncture and for guidance during venous access. More recently, intravascular US (IVUS) has been used as an imaging method before and during filter placement. [104]

CT scanning and MRI

CT scanning and MRI have been used to visualize the size, configuration, and anatomic variants of the IVC.

Inferior vena cavography

Currently, cavography is the modality used most commonly to assess the IVC, usually before filter placement. Access to the IVC is typically achieved via a left or right femoral vein or via the right internal jugular vein. The right femoral vein is the most common approach, accounting for 69% in a series reported by Athanasoulis et al. [5] US may be used to guide the puncture. After access into the venous system is gained, a pigtail catheter is typically positioned near the confluence of the common iliac veins.

Alternatively, catheter placement in the left common iliac vein enables visualization of both a normal IVC and a duplicated IVC, which is a normal variation of a double IVC.

In patients at intermediate risk for an adverse reaction to the contrast material and in patients with compromised renal function, cavography can be performed with carbon dioxide.

Various methods can be used to determine the diameter of the IVC, especially when digital subtraction angiography is performed. These include placement of a ruler with metallic markers along the left side of the patient's body and the use of marker catheters or guidewires.

In most centers, a single frontal projection is used for measurement, but biplane studies can also be used during the procedure.

More recently, investigators have advocated the use of preprocedural cross-sectional imaging for a more accurate assessment of the caval diameter.


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