ABSTRACT. Anatomically, the inferior vena cava (IVC) courses through the liver posteriorly and drains into the right atrium. We describe an extremely rare case of the anterior intrahepatic course of the IVC that drained into the right atrium seen on a CT scan of a healthy 26-year-old female who presented to the emergency room with abdominal pain. The anterior intrahepatic segment was bridged to the posteroinferior portion of the IVC by an oblique segment. Associated renal and arterial anomalies were also observed in our patient. Since the development of cross-sectional imaging, congenital anomalies of the inferior vena cava (IVC) and its tributaries have been encountered more frequently in asymptomatic patients [1,2]. Vascular structures are usually readily identified on CT scans of the abdomen and pelvis obtained with intravenously administered contrast material.Multiple congenital anomalies of IVC have been described in the literature including left-sided IVC, double IVC, azygos continuation of the IVC, circumaortic left renal vein and retroaortic left renal vein [3,4]. Other anomalies include the absence of the infrarenal IVC or the entire IVC. Some variations are associated with congenital heart disease, but detection of unusual IVC system in patients without any clinical symptoms by CT is not uncommon [5].We describe an extremely rare case of an anteriorly located variant intrahepatic course of the IVC with an oblique segment bridging this anterior intrahepatic segment with the posterior inferior segment of the IVC. In reporting this case, we have used maximum intensity projection (MIP) imaging to depict the structural relationship of IVC to adjacent viscera. Case reportA 26-year-old female presented to the emergency room with a 3 day history of generalised abdominal pain and vomiting. Medical and surgical histories were unremarkable. The patient had no known history of IVC dissection or iatrogenic IVC injuries. Laboratory values were within normal limits. A contrast-enhanced CT scan was performed to exclude bowel pathology.Incidentally, CT imaging showed an intrahepatic portion of the IVC coursing anteriorly through the liver and the diaphragm with anatomical insertion into the right atrium (Figure 1a). This anterior intrahepatic segment was bridged to the posteroinferior portion of the IVC by an oblique segment (Figure 1d). The inferior phrenic veins were not well visualised. The hepatic veins were seen traversing anteriorly to insert into the ventrally located intrahepatic IVC (Figure 1c). The renal veins were seen coursing anteriorly to drain into the oblique segment (Figure 1b). Normal morphology was observed within the portal venous system. The infrarenal IVC demonstrated a normal retroperitoneal course and calibre without any associated anomalies. The ovarian veins demonstrated a normal drainage pattern with the left ovarian vein draining into the left renal vein and the right ovarian vein draining into the infrarenal IVC. The lumbar veins were not enlarged and demonstrated a normal course. The commo...

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A 6 3-year-old man with acute onset of abdominal pain had portal vein gas clearly visible on pre-operative X-ray. The ethical and practical aspects of management of such cases are discussed and the radiographic features allowing differentiation of air in the biliary tree from air in the portal vein.