title: Is CT cystography an accurate study in the evaluation of spontaneous perforation of augmented bladder in children and adolescents?
abstract: BACKGROUND
  Spontaneous bladder perforation (SBP) is a potentially fatal complication of augmented bladder. Imaging is often used for diagnosis. In this study we present our experience with CT cystography (CTC) in the diagnosis of SBP.
  
  
  OBJECTIVE
  To determine CTC accuracy in the evaluation of SBP in children with an augmented bladder.
  
  
  METHODS
  The institutional review board approved this HIPAA-compliant study; informed consent was waived. All patients under 20 years old, who underwent CTC for SBP evaluation from 2003 to 2013, were identified. Two radiologists independently reviewed CTC studies for contrast extravasation, ascites, and pneumoperitoneum. Ascites was graded: small - confined to the rectovesical pouch (RVP); moderate - beyond the RVP; large - beyond the pelvis.
  
  
  RESULTS
  Eighty-nine patients (47 males, age 4.2-19.8 years) had 132 CTCs. SBP was diagnosed in 14% (19/132). Both radiologists found contrast extravasation in 74% (14/19) of patients with SBP; two patients had only pneumoperitoneum, and three had only ascites (large = 2, moderate = 1) (Fig.). SBP was found in 1% of CTCs with no ascites or small ascites (1 of 98 and 92; radiologists 1 and 2, respectively). Findings of extraluminal extravasation, unexplained pneumoperitoneum, or large ascites, yielded a detection rate of 95% for SBP by each radiologist. In eight patients, small bowel obstruction was diagnosed.
  
  
  CONCLUSIONS
  Contrast extravasation was detected in only 74% of patients with SBP. The use of indirect signs of perforation (unexplained pneumoperitoneum and large ascites) in addition to contrast extravasation, increased the detection rate of SBP to 95%. US screening for SBP and selection of patients with moderate or large ascites for CTC, may eliminate the need for most CT scans. In the absence of SBP, other abdominal abnormalities should be evaluated. Bowel obstruction was the most common non-urological emergency detected in this series. The main limitations of the study are: the small number of SBP cases; the diagnosis of SBP not based on surgical findings in three patients; and inability to completely exclude occult SBP in patients not explored surgically.
  
  
  CONCLUSIONS
  Extraluminal contrast was seen on CTC in most cases of SBP, but some patients with sealed bladder perforation had only pneumoperitoneum or moderate/large ascites. Therefore, SBP should be suspected in any patient with moderate/large volumes of pelvic fluid or unexplained pneumoperitoneum, even when there is no evidence of contrast extravasation. Patients with no ascites, or small volumes, are unlikely to have SBP; therefore, US can be used to screen low risk patients.
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA. Electronic address: bkarmazy@iupui.edu.
authors.forename: Boaz
authors.initials: B
authors.lastname: Karmazyn
authors.affiliation: Department of Urology, North Shore-LIJ School of Medicine Long Island Jewish Medical Center, New York, NY, USA.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Gurram
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA.
authors.forename: Megan B
authors.initials: MB
authors.lastname: Marine
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA.
authors.forename: Wanner R
authors.initials: WR
authors.lastname: Mathew
authors.affiliation: Department of Urology, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Cain
authors.affiliation: Department of Urology, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Rink
authors.affiliation: Department of Biostatistics, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: George J
authors.initials: GJ
authors.lastname: Eckert
authors.affiliation: Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: S Gregory
authors.initials: SG
authors.lastname: Jennings
authors.affiliation: Department of Urology, Indiana University School of Medicine, Riley Hospital for Children, Indianapolis, IN, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Kaefer
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012422:Rupture, Spontaneous; D014057:Tomography, X-Ray Computed / Q000379:methods*; D001743:Urinary Bladder / Q000000981:diagnostic imaging* / Q000601:surgery; D014549:Urinary Incontinence / Q000000981:diagnostic imaging / Q000601:surgery*; D014567:Urography / Q000379:methods*; D013520:Urologic Surgical Procedures / Q000009:adverse effects*; D055815:Young Adult
keywords: Augmented bladder; CT cystography; Children; Perforation