title: Beware of false-negative CT scan for anastomotic leakage after colonic surgery.
abstract: BACKGROUND
  Anastomotic leakage is one of the most life-threatening complications after colonic surgery. Correct diagnosis and treatment is important to reduce morbidity and mortality. An abdominal CT scan is one of the main diagnostic tools in diagnosing anastomotic leaks. The aim of this study was to examine the accuracy of abdominal CT scanning to detect anastomotic leakage and to evaluate the consequences of a false-negative CT outcome.
  
  
  METHODS
  All consecutive patients who underwent colonic resection for malignant disease between 2009 and 2011 or for benign disease in 2010 were reviewed. Patients in whom a postoperative abdominal CT scan was performed to detect anastomotic leakage were included.
  
  
  RESULTS
  In 97 of 524 patients who underwent colonic surgery, an abdominal CT scan was performed for the suspicion of anastomotic leakage. Overall leakage rate was 10.9 % (n = 57). Mortality rate after leakage was 21.1 % (n = 12). Results from all abdominal CT scans revealed an overall sensitivity of 0.59 (95 % CI 0.43-0.73), a specificity of 0.88 (95 % CI 0.75-0.95), positive predictive value 0.82 (95 % CI 0.64-0.92), negative predictive value 0.70 (95 % CI 0.57-0.81), and an accuracy of 74 %. Delayed reintervention for anastomotic leakage due to a false-negative CT outcome resulted in death in 62.5 % (n = 5).
  
  
  CONCLUSIONS
  The sensitivity of abdominal CT scanning after colonic surgery is relatively low. A negative CT scan does not rule out anastomotic leakage. Even with a negative CT scan, we should remain equally alert at clinical deterioration as an argument for timely intervention.
authors.affiliation: Department of Surgery, St. Antonius Hospital, Koekoekslaan 1, 3435 CM, Nieuwegein, The Netherlands, vnnkornmann@gmail.nl.
authors.forename: Verena N N
authors.initials: VN
authors.lastname: Kornmann
authors.forename: Bert
authors.initials: B
authors.lastname: van Ramshorst
authors.forename: Anke B
authors.initials: AB
authors.lastname: Smits
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Bollen
authors.forename: Djamila
authors.initials: D
authors.lastname: Boerma
mesh_terms: D000714:Anastomosis, Surgical / Q000009:adverse effects; D057868:Anastomotic Leak / Q000000981:diagnostic imaging*; D003106:Colon / Q000601:surgery*; D003108:Colonic Diseases / Q000601:surgery; D003110:Colonic Neoplasms / Q000601:surgery; D005188:False Negative Reactions; D006801:Humans; D011860:Radiography, Abdominal / Q000379:methods; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed