Duplicated gall bladder detected on 99m Tc HIDA hepatobiliary scintigraphy: A report of two cases
A 15 year old boy presented with intermittent pain in right hypochondrium for a week. Physical examination revealed no local tenderness. Liver function parameters were normal. Ultrasonography (USG) of the abdomen revealed two cystic formations in the gall bladder (GB) fossa with no distinct visualisation of cystic duct. No GB wall thickening was noted, thus ruling out GB diverticula. Differential diagnosis of choledochal cyst and duplicated GB was given. Patient was then referred for a 99m Tc hepatobiliary scintigraphy. After fasting for 6-8 hours, 5 mCi of 99m Tc mebrofenin (HIDA) was injected intravenously and dynamic images were acquired for 1 hour, at a frame rate of 1 minute/second. Images revealed normal hepatocellular tracer extraction with visualization of the hepatic and common bile ducts at 10 minutes. Two foci of tracer uptake were seen in the region of GB fossa [-arrows] at 15 minutes, which persisted till the end of the study. Anterior static pre fatty meal image showed two intense foci of tracer uptake in GB fossa [-arrow]. Patient then consumed a fatty meal. Post fatty meal anterior static image showed reduction in size and counts in both structures in GB fossa [-arrows]. Detection of two globular structures in GB fossa, which contract after fatty meal, is specific for duplicated GB. It was further confirmed by drawing regions of interest (ROIs) on GB moieties, on pre and post meal images, which showed reduction in counts by more than 50%. Since GB visualization was within normal time range, with preserved contractile function post fatty meal, patient was kept on medical therapy, low fat diet and antibiotics, and follow up was recommended.