ABSTRACT
Objective To investigate the imaging features of computed tomography (CT) examination of subacute gallbladder perforation.Methods The retrospective cross-sectional study was conducted.The clinical data of 24 patients with subacute gallbladder perforation who were admitted to the Affiliated Wuxi No.2 People's Hospital of Nanjing Medical University between January 2013 and January 2018 were collected.Patients underwent abdominal plain scan and enhanced scan in the arterial phase and portal venous phase of CT,and received percutaneous cholecystostomy,cholecystectomy,choledocholithotomy,T-tube drainage according to their conditions.Observation indicators and evaluation criteria:(1) CT examination situations."Barrier lake sign" is defined as presence of obvious or occult crevasse in the discontinuous gallbladder wall,with interrupt line seen in the portal venous phase and without crevasse enhancement.There is patchy effusion circled by annular wall around crevasse of gallbladder,shape like barrier lake,appearing as oval,semicircle,circular sector,triangle,etc.Annular wall consists of abscess wall,liver margin or both of them.With smooth inner wall of the abscess and irregular outer wall,abscess wall may be complicated with inflammatory exudation and strip shadow,showing intense enhancement in the venous phase.(2) Treatment and follow-up situations.Follow-up using outpatient examination and telephone interview to detect complications after discharge up to January 2018.Measurement data with skewed distribution were represented as M (range).Results (1) CT examination situations.① Completion status and primary diseases:of 24 patients,2 underwent abdominal plain scan,22 underwent abdominal plain scan combined with enhanced scan in the arterial phase and portal venous phase.The primary disease of all the 24 patients was biliary stone,including 18 located in gallbladder cavity,4 located at gallbladder neck and 2 combined with gallbladder stones and common bile duct stones.The maximum diameter was 2.0 cm (range,0.3-2.5 cm)in the 24 patients.② Crevasse of subacute gallbladder perforation:perforations were detected at the bottom of gallbladder in 11 patients,at body of gallbladder in 7 patients (1 with multiple perforations),at gallbladder neck in 1 patient,at bottom and body of gallbladder in 2 patients,and perforation spot was unable to judge in 3 patients.The maximum diameter of occult crevasses was ＜0.2 cm in 2 patients and maximum diameter of crevasses was 0.5 cm (range,0.2-1.0 cm) in other 22 with defined perforation spot.③ Imaging manifestations of "barrier lake sign":24 patients had manifestation of "barrier lake sign".Annular wall consisted of abscess wall,liver margin or both of them was found in 15,3,6 patients respectively.Gallbladder was partially or totally wrapped by abscess in 21 and 3 patients respectively.④ Gallbladder situation:of 24 patients,23 and 1 had gall bladder volume increased significantly and decreased slightly,with a maximum diameter of 10.0 cm (range,6.0-13.0 cm) and thickness of hydropic gallbladder wall as 0.5 cm (range,0.3-1.3 cm).⑤ Other effusion signs:24 patients had increased fat interval density around gallbladder,partly showing cord-like and line-like changes.(2) Treatment and follow-up situations:of 24 patients,10 underwent laparoscopic cholecystectomy,6 underwent open cholecystectomy,4 underwent cholecystectomy + choledocholithotomy + T-tube drainage,1 was converted to open cholecystectomy + choledocholithotomy + T-tube drainage after laparoscopic exploration,3 underwent cholecystectomy at 2 months after percutaneous cholecystostomy combined with anti-inflammatory treatment.Of 24 patients,22 were followed up for 6-31 months with a median time of 11 months.During the follow-up,2 patients were detected residual stones at fossa for gallbladder and end of the common bile duct,2 were detected cholangitis with stones,1 died of tumor,and other 17 survived well without recurrence of calculus or other complications.Conclusion The "barrier lake sign" is a typical feature of CT examination of subacute gallbladder perforation,which provides timely and accurately differential diagnosis and clinical treatment.