title: Quality of virtual colonoscopy in patients who have undergone radiation therapy or surgery: how successful are we?
abstract: OBJECTIVE
  In patients who have a history of abdominopelvic radiation, surgery, or both, conventional colonoscopy may fail to examine the entire colon. The purpose of this study is to assess whether high-quality virtual colonoscopy can be achieved in this patient population.
  
  
  METHODS
  After colonic cleansing, 61 patients (16 men and 45 women; mean age, 64 years; age range, 27-81 years) underwent 63 virtual colonoscopy examinations after using either single- or multidetector CT (slice thickness, 3.75-5.0 mm; table speed, 1.7-11.25 cm/sec; pitch, 1.5-3.0; and overlapped reconstructions, 1.95-2.5 cm) in supine and prone positions after IV administration of 1 mg of glucagon and rectal air insufflation. Conventional two-dimensional axial images were analyzed on a PACS (picture archiving and communication system) workstation. Two radiologists, who were unaware of patient history, independently evaluated the colonic distention on a 4-point scale (4 = optimal distention) and fluid retention on a 3-point scale (3 = no fluid) for all segments of the colon in patients who were imaged in both the supine and prone positions. Segmental and total average colon scores were calculated.
  
  
  RESULTS
  Forty-one patients (65%; 43 examinations, 67%) underwent prior surgery, radiation, or both (surgery, n = 29; radiation, n = 3; both, n = 11). The average overall colonic distention and fluid retention for this group was 3.13 and 2.38, respectively, versus 3.24 and 2.3 in the control group (p = not significant).
  
  
  CONCLUSIONS
  High-quality examinations were achieved in patients who had previously undergone radiation, surgery, or both with no clinically significant difference in distention or fluid retention compared with the controls.
authors.affiliation: Department of Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Ave., New York, NY 10021, USA.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Gollub
authors.forename: Michelle S
authors.initials: MS
authors.lastname: Ginsberg
authors.forename: Cathleen
authors.initials: C
authors.lastname: Cooper
authors.forename: Howard T
authors.initials: HT
authors.lastname: Thaler
mesh_terms: D000005:Abdomen / Q000528:radiation effects* / Q000601:surgery*; D000008:Abdominal Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003110:Colonic Neoplasms / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010386:Pelvic Neoplasms / Q000532:radiotherapy* / Q000601:surgery*; D010388:Pelvis / Q000528:radiation effects* / Q000601:surgery*; D012680:Sensitivity and Specificity