title: Feasibility study of using air as a contrast medium in MR colonography.
abstract: OBJECTIVE
  To evaluate the feasibility of using air as intraluminal contrast medium in magnetic resonance (MR) colonography.
  
  
  METHODS
  Twenty-two patients underwent MR colonography (MRC) using air before colonoscopy. All patients were imaged in prone and supine positions. Each colon was divided into five segments. Two radiologists reviewed the images for the degree of colonic distension, image quality and colonic lesions. The colonic lesions identified using MR were compared with those identified on colonoscopy.
  
  
  RESULTS
  Eight men and 14 women with mean age of 55.5 years were studied. All patients completed the MR examination. One hundred and five out of 110 (95.5%) colonic segments were well distended in both prone and supine positions. Image quality was good in all cases. Colonoscopy detected 16 lesions: three > or = 1 cm, one 7 mm lesion and 12 lesions < or = 5 mm. All lesions 1 cm or larger were detected by MRC.
  
  
  CONCLUSIONS
  MRC using air and the single-shot half-Fourier rapid acquisition with refocused echoes (RARE) technique is feasible. But in this small pilot study, it had low sensitivity for the detection of polyps less than 1 cm in diameter.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Prince of Wales Hospital, Hong Kong, People's Republic of China. so2173@cuhk.edu.hk
authors.forename: N M C
authors.initials: NM
authors.lastname: So
authors.forename: W W M
authors.initials: WW
authors.lastname: Lam
authors.forename: D
authors.initials: D
authors.lastname: Mann
authors.forename: K L
authors.initials: KL
authors.lastname: Leung
authors.forename: C
authors.initials: C
authors.lastname: Metreweli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000388:Air; D003111:Colonic Polyps / Q000175:diagnosis; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects
chemical_list: D003287:Contrast Media