---

IODINATED CONTRAST IN GALL BLADDER FOLLOWING ORAL INGESTION OF CONTRAST MEDIA : CT DEMONSTRATION OF DUODENO-BILIARY REFLUX

Srinivasa Prasad, Tufail Patankar
Dept. of Radiology, KEM Hospital, Mumbai, India.

---

Contrast opacification of the biliary tree in the absence of previous history of surgical intervention suggests the presence of biliary-enteric fistula. We describe the CT scan findings documenting orally administered contrast medium in the gall bladder in a patient with past history of biliary calculus disease.

INTRODUCTION

Bile within the gall bladder in common with other biologic fluids in the body appear hypodense (5-10 Hounsfield Units) on plain CT scan. Hyperdense fluid in the gall bladder on plain CT scan of the abdomen is usually the result of acute haemorrhage. Oral contrast may enter the biliary tree and also appear hyperdense. The potential for confusion in differentiating the two conditions exists if only contrast CT scans are performed. Correct interpretation rests on detecting high attenuation value of the iodinated contrast medium (100-130 Hounsfield Units) which clinches the diagnosis. Thus recognition of this phenomenon has important diagnostic implications which is reassuring to both the patient and the referring physician.

CASE REPORT

A seventy three year old man underwent plain and contrast enhanced CT scan of the for abdomen investigation of abdominal pain. The patient admitted to a past history of biliary calculus disease. Plain CT scan revealed hyperdense fluid in the gall bladder (100-125 Hounsfield Units). Contrast opacification of the gall bladder secondary to duodeno-biliary reflux of oral contrast media was thus identified.

DISCUSSION

Contrast opacification of the biliary three following barium studies usually signifies surgically created biliary-enteric anastomoses. Biliary-enteric fistulization secondary to inflammatory and neoplastic conditions of either the gut or the biliary tree constitutes important causes of contrast opacification of biliary tree secondary to ingestion of contrast media. Duodeno-biliary reflux secondary to incompetent sphincter of Oddi is an uncommon cause of this phenomenon. The causes of duodeno-biliary reflux include chole-lithiasis-choledocholithiasis,[1] chronic pancreatitis, pan- creatic carcinoma, duodenal Crohn’s disease and duodenal or intestinal obstruction. [2] All these conditions cause transient or permanent incompetence of the sphincter of Oddi predisposing and leading to duodeno-biliary reflux. Transient incompetence of the sphincter of Oddi may also occur in normal individuals predisposing to duodeno-biliary reflux. Recognition of the oral contrast within the gall bladder is important from the diagnostic point of view. Hyperdense fluid in gall bladder may represent acute haemorrhage secondary to trauma, surgery or bleeding tumour. Differentiation of contrast media from haemorrhage is rendered difficult if the plain CT examination is not done. Blood can be readily identified on plain CT scan because the attenuation of acute clotted blood is 55-65 Hounsfield Units. Prompt identification of this phenomenon avoids wrong diagnosis and probable unnecessary surgery.

REFERENCES

1. Lary MA, Meier DE. Sphincter incompetence caused by common bile duct stones.
   Surgery 1983; 93 (4) : 538-540.
2. Kirks DR, Baden M. Incompetence of sphincter of Oddi associated with duodenal
   stenosis. Journal of Paediatrics
   1973; 83 : 838-40.

To Section TOC