title: Magnetic resonance colonography for the detection of colorectal neoplasia in asymptomatic adults.
abstract: OBJECTIVE
  Colonoscopy is the preferred screening test for colorectal neoplasia; the fecal occult blood test (FOBT) detects neoplasias with low levels of sensitivity. Computed tomographic colonography detects neoplasias with high levels of sensitivity but involves exposure to radiation. We investigated whether magnetic resonance colonography (MRC) can be used to screen for colorectal adenomas and cancers.
  
  
  METHODS
  We analyzed data from 286 asymptomatic adults (40-82 years old) who underwent 3 Tesla MRC and colonoscopic examinations on the same day. FOBT was performed before bowel preparation. Colonoscopists were initially blinded to the findings on MRC and unblinded after withdrawal from the respective segments. Sensitivities for adenoma and per-patient sensitivities and specificities were calculated based on the unblinded results of colonoscopy.
  
  
  RESULTS
  We detected 133 adenomas and 2 cancers in 86 patients; 37 adenomas were ≥6 mm, and 20 adenomas were advanced. Sensitivities of MRC and colonoscopy for adenomas ≥6 mm were 78.4% (95% confidence interval [CI], 61.8-90.2) and 97.3% (95% CI, 85.8-99.9); for advanced adenomas these values were 75% (95% CI, 50.9-91.3) and 100% (95% CI, 83.2-100.0), respectively. MRC identified 87.1% (95% CI, 70.2-96.4), colonoscopy 96.8% (95% CI, 83.3-99.9), and FOBT 10.0% (95% CI, 2.1-26.5) of individuals with adenomas ≥6 mm and 83.8% (95% CI, 58.6-96.4), 100% (95% CI, 81.5-100.0), and 17.6% (95% CI, 3.8-43.4) of individuals with advanced neoplasia. Specificities of MRC, colonoscopy, and FOBT for individuals with adenomas ≥6 mm were 95.3% (95% CI, 91.9-97.5), 96.9% (95% CI, 93.9-98.6), and 91.8% (95% CI, 87.6-94.9), respectively.
  
  
  CONCLUSIONS
  3 Tesla MRC detects colorectal adenomas ≥6 mm and advanced neoplasia with high levels of sensitivity and specificity. Although MRC detects colorectal neoplasia with lower levels of sensitivity than colonoscopy, it strongly outperforms one-time FOBT.
authors: Department of Clinical Radiology, University of Munich, Munich, Germany. anno.graser@med.uni-muenchen.de
authors: Anno
authors: A
authors: Graser
authors: Anja
authors: A
authors: Melzer
authors: Evelyn
authors: E
authors: Lindner
authors: Dorothea
authors: D
authors: Nagel
authors: Karin
authors: K
authors: Herrmann
authors: Petra
authors: P
authors: Stieber
authors: Jörg
authors: J
authors: Schirra
authors: Ulrich
authors: U
authors: Mansmann
authors: Maximilian F
authors: MF
authors: Reiser
authors: Burkhard
authors: B
authors: Göke
authors: Frank T
authors: FT
authors: Kolligs
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D000236:Adenoma / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003113:Colonoscopy / Q000379:methods; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009780:Occult Blood; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D017678:Sex Distribution