title: Comparison of qualitative and quantitative approach to prostate MR spectroscopy in peripheral zone cancer detection.
abstract: OBJECTIVE
  To compare the diagnostic performance of a qualitative (pattern recognition) and a quantitative (numerical assessment) approach to magnetic resonance spectroscopy (MRS) in the diagnosis of peripheral zone prostate cancer.
  
  
  METHODS
  185 patients (131 with histopathologically proven cancer, 54 normal/benign after at least 12 months follow-up) were prospectively evaluated with qualitative MRS using a 4-point scale between 3/2004 and 1/2008, and retrospectively reassessed using a prototype quantitative postprocessing software in April 2008. Based on pathology and follow-up data, diagnostic performance parameters were calculated.
  
  
  RESULTS
  The qualitative and quantitative approaches were concordant in 78.9% (146/185) of cases. The difference between the areas under the ROC curve (0.791 versus 0.772, respectively) was not statistically significant. The sensitivity, specificity and accuracy were 55.7%, 94.4% and 67.0% for the qualitative approach, and 55.0%, 83.3% and 63.2% for the quantitative approach. The sensitivity for high grade tumours (Gleason 4+3 or higher) was 85.2% (23/27) for both approaches. All cancers missed on either one approach separately (31/31) and 91% of cancers missed on both approaches together (23/27) were of lower grade (Gleason 3+4 or lower).
  
  
  CONCLUSIONS
  Qualitative and quantitative approaches to MRS yield similar diagnostic results. Discordances in tumour detection only occurred in lower grade cancers.
authors.affiliation: Division of Genitourinary Radiology, Ghent University Hospital, De Pintelaan 185, 9000 Gent, Belgium.
authors.forename: Stijn
authors.initials: S
authors.lastname: Klijn
authors.forename: Pieter J
authors.initials: PJ
authors.lastname: De Visschere
authors.forename: Gert O
authors.initials: GO
authors.lastname: De Meerleer
authors.forename: Geert M
authors.initials: GM
authors.lastname: Villeirs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010363:Pattern Recognition, Automated; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000175:diagnosis* / Q000473:pathology; D012372:ROC Curve; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012984:Software