Volume rendering of three-dimensional drip infusion CT cholangiography in patients with suspected obstructive biliary disease: a retrospective study

The purpose of this study was to evaluate the diagnostic potential of prolonged drip infusion CT cholangiography (DIC-CT) using meglumine iotroxate (BiliscopinH) and 3D volume rendering in patients with suspected obstructive biliary disease. From a material of 142 patients who had undergone a drip infusion CT, all cases with a verified surgical or endoscopic retrograde cholangiography (ERC) diagnosis (n533) were selected. Age-matched controls were selected from the remaining examinations. Three radiologists reviewed all 66 examinations in retrospect, independently as well as in consensus. The image quality and the estimated diagnostic quality were rated as good or moderate in 91% of the 198 reviews. The consensus sensitivity and specificity for diagnosing biliary stones was 88% and 94%, respectively (with sensitivities ranging from 88% to 94% for individual observers, and specificities from 86% to 96%). Two out of three strictures were observed. No false positive strictures were described. The use of volume rendering technique (VRT) improved diagnostic certainty in 28/198 (14%) of the evaluations. The visualization of ductal stones was improved in 18/48 (38%). No differences in diagnostic quality between single and multislice CT were observed. We conclude that a detailed image of the biliary tree with good sensitivity and specificity can be obtained by means of bilirubin-governed infusion time DIC-CT with volume rendering reconstruction. Suspected biliary tract disease is a common clinical problem. A full radiological evaluation of the biliary tract should not only provide information regarding the presence of an obstruction, but also define the level and the cause of the obstruction. Advances in ultrasound, CT and MR technology over the past decade have greatly improved our ability to make this evaluation. In spite of the indisputable success of ultrasound and MRI, an alternative non-invasive diagnostic method is still required in those cases with inconclusive ultrasound findings or contraindications to MRI. In patients with unclear abdominal pain, CT is often used. However, CT without contrast administration often fails to resolve the non- dilated bile duct from the surrounding tissue. Also, stones in the common bile duct (CBD) are isodense with bile in up to 80% of cases (1). When an intravenous biliary contrast agent is used, however, gallstones are more easily detected. material, meglumine iotroxate (BiliscopinH; Schering AG, Berlin, Germany), with a new scheme of prolonged drip infusion CT cholangiography (DIC-CT) in patients with suspected obstructive biliary disease.