Intravenous cholangiography: pitfalls in interpretation.

Abstract

Shortly after the introduction of Cholografin, numerous reports stressing the excellence of this new agent for the direct investigation of the biliary tree appeared. In the hands of Bell, Berk, Glenn, Orloff, their associates, and others (1–4), and at our own hospital, symptomatic postcholecystectomy states often have been resolved into basic abnormalities amenable to definitive therapy. Unusual conditions in the region of the intra-and extrahepatic biliary tree, including tumor, inflammation, and sinus tracts, have been visualized with Cholografin. Gallbladders unresponsive to oral cholecystographic media have been opacified, allowing positive preoperative diagnoses. The purpose of this report is not to detract from the proved worth of intravenous cholangiography with Cholografin, but to illustrate several pitfalls in the interpretation of such roentgenographic studies and means for their avoidance. Pitfalls A. Masking Effect of Small Lucent Calculi: Small lucent calculi may be missed, their presence masked by the dense opacification occasionally produced by Cholografin even in a diseased gallbladder. B. I mages Produced by Overlap of Shadows: The superimposition of shadows of organs in the right upper quadrant of the abdomen, i.e. the sharp edge of the liver, the renal silhouette, and loops of bowel which rnay contain some of the opaque material, often produce deceiving images on the radiograph. In particular, the overlapping shadows of liver and kidney may be confused with the gallbladder. C. Renal versus Biliary Clearance: In the early phase of excretion, renal clearance may simulate biliary passage, and vice versa. This is especially true when the right renal pelvis is bifid and the superior major calyceal system is on the same anteroposterior plane as the biliary ducts. D. Stratification Phenomenon: 0n occasion, Cholografin may gravitate to the dependent portion of a normal gallbladder, with preservation of the interface between the bile and iodinated media, producing a unique circular radiolucency suggesting a large lucent stone or free gas within the gallbladder. Case Reports The following cases illustrate these patential errors. CASE I: A ;57-year-old male was admitted to the Bronx Veterans Administration Hospital acutely ill, complaining of epigastric pain, nausea, and vomiting. He related a history of long-standing intolerance to fatty foods. There were no urinary complaints or findings. A plain film of the abdomen disclosed a suspicious calcification in the right upper quadrant (Fig. 3A). Oral cholecystography demonstrated a gallbladder having a phrygian cap and containing numerous small radiolucent stones (Fig. IB). The calcification previously noted was again seen and considered possibly to be within the common bile duct.