Pelvic venous variations in patients with congenital inferior vena cava anomalies : Classification with computed tomography

Background: Pelvic venous variations of congenital inferior vena cava (IVC) anomalies that have the potential to cause problems during related surgery and interventional radiology are not fully appreciated.Purpose: To classify pelvic venous variations of congenital IVC anomalies using computed tomography (CT).Material and Methods: CT images for 36 patients with congenital IVC anomalies were retrospectively reviewed. Pelvic venous variations were classified with regard to the relationship with the iliac veins and the presence of interiliac communication.Results: Pelvic venous variations were classified into eight types. One azygous continuation displayed normal connection with the bilateral common iliac veins (CIV) (type 1). Of 28 double IVCs, 11 (39.3%) displayed no interiliac communication (type 2a), five (17.9%) displayed interiliac communication from the left CIV (type 2b), one (3.6%) had communication from the right CIV (type 2c), six (21.4%) had communication from the left internal iliac vein (IIV) (...