Inferior vena cava filling defects on CT and MRI.

OBJECTIVE: The purpose of this article is to describe the appearance and causes of inferior vena cava (IVC) filling defects, how such findings may be accurately characterized, and the clinical significance of IVC filling defects. Filling defects in the IVC observed at MDCT and MRI may be a result of flow artifacts, anatomic variants, or bland or malignant thrombus.

CONCLUSION: Familiarity with anatomy and flow effects is critical for distinguishing true from false filling defects in the IVC. Delayed imaging after administration of IV contrast material and dedicated MRI sequences may be helpful for further characterization of such findings. Once a true filling defect of the IVC is established, identification of the cause, whether benign or malignant, and extent will guide clinical treatment.