title: A prospective, blinded comparison of laparoscopic ultrasound with transabdominal ultrasound for the detection of gallbladder pathology in morbidly obese patients.
abstract: BACKGROUND
  Transabdominal ultrasound (TAU) is the gold standard for detecting cholelithiasis. Morbid obesity can inhibit detection of gallbladder pathology due to increased subcutaneous and visceral fat. Laparoscopic ultrasound (LUS) has the potential to overcome these technical challenges. We hypothesized that LUS would have a sensitivity and specificity similar to TAU for detecting cholelithiasis and polyps in morbidly obese patients presenting for laparoscopic Roux-en-Y gastric bypass.
  
  
  METHODS
  After Institutional Review Board approval, patients underwent preoperative TAU and intraoperative LUS during laparoscopic Roux-en-Y gastric bypass. Certified ultrasonographers performed all TAUs. Surgeons, blinded to TAU results, performed the LUS. Presence of cholelithiasis or polyps and common bile duct diameter was evaluated. Statistical analysis included chi-square and McNemar's test.
  
  
  RESULTS
  Two hundred and fifty-three patients were prospectively enrolled during a 6-year period. Seventy-six percent were female, mean age and preoperative body mass index (calculated as kg/m(2)) were 43.5 years and 48, respectively. Mean time to complete the LUS was 4 minutes. Mean common bile duct diameter measured 3.7 mm via LUS and 4.0 mm via TAU. Transabdominal ultrasound and LUS identified 61 and 60 patients with cholelithiasis, respectively (p = 0.763). The sensitivity and specificity of LUS for cholelithiasis was 90.2% and 97.4%. Laparoscopic ultrasound identified polyps in 41 patients, and TAU identified polyps in 6 patients, 5 of which had polyps identified on LUS as well (p < 0.001). Sensitivity and specificity of LUS for polyps was 83.3% and 85.4%.
  
  
  CONCLUSIONS
  Laparoscopic ultrasound is equivalent to TAU in detecting cholelithiasis, however, LUS detected significantly more polyps. Intraoperative LUS is an appropriate alternative to TAU in patients undergoing laparoscopic Roux-en-Y gastric bypass.
authors.affiliation: Department of General and Vascular Surgery, Gundersen Lutheran Health System, La Crosse, WI 54601, USA. snkothar@gundluth.org
authors.forename: Shanu N
authors.initials: SN
authors.lastname: Kothari
authors.forename: Kosisochi M
authors.initials: KM
authors.lastname: Obinwanne
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Baker
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Mathiason
authors.forename: Kara J
authors.initials: KJ
authors.lastname: Kallies
mesh_terms: D000328:Adult; D002763:Cholecystectomy; D003937:Diagnosis, Differential; D004311:Double-Blind Method; D019160:Endosonography / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D005705:Gallbladder Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000601:surgery; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D009767:Obesity, Morbid / Q000150:complications* / Q000000981:diagnostic imaging; D057234:Preoperative Period; D011446:Prospective Studies; D015203:Reproducibility of Results