title: CT colonography: preliminary assessment of a double-read paradigm that uses computer-aided detection as the first reader.
abstract: OBJECTIVE
  To compare diagnostic performance and time efficiency of double-reading first-reader computer-aided detection (CAD) (DR FR CAD) followed by radiologist interpretation with that of an unassisted read using segmentally unblinded colonoscopy as reference standard.
  
  
  METHODS
  The local ethical committee approved this study. Written consent to use examinations was obtained from patients. Three experienced radiologists searched for polyps 6 mm or larger in 155 computed tomographic (CT) colonographic studies (57 containing 10 masses and 79 polyps ≥ 6 mm). Reading was randomized to either unassisted read or DR FR CAD. Data sets were reread 6 weeks later by using the opposite paradigm. DR FR CAD consists of evaluation of CAD prompts, followed by fast two-dimensional review for mass detection. CAD sensitivity was calculated. Readers' diagnoses and reviewing times with and without CAD were compared by using McNemar and Student t tests, respectively. Association between missed polyps and lesion characteristics was explored with multiple regression analysis.
  
  
  RESULTS
  With mean rate of 19 (standard deviation, 14; median, 15; range, 4-127) false-positive results per patient, CAD sensitivity was 90% for lesions 6 mm or larger. Readers' sensitivity and specificity for lesions 6 mm or larger were 74% (95% confidence interval [CI]: 65%, 84%) and 93% (95% CI: 89%, 97%), respectively, for the unassisted read and 77% (95% CI: 67%, 85%) and 90% (95% CI: 85%, 95%), respectively, for DR FR CAD (P = .343 and P = .189, respectively). Overall unassisted and DR FR CAD reviewing times were similar (243 vs 239 seconds; P = .623); DR FR CAD was faster when the number of CAD marks per patient was 20 or fewer (187 vs 220 seconds, P <01). Odds ratio of missing a polyp with CAD decreased as polyp size increased (0.6) and for polyps visible on both prone and supine scans (0.12); it increased for flat lesions (9.1).
  
  
  CONCLUSIONS
  DR FR CAD paradigm had similar performance compared with unassisted interpretation but better time efficiency when 20 or fewer CAD prompts per patient were generated.
authors: Radiology Unit, Institute for Cancer Research and Treatment, FPO, Strada Provinciale 142, Km 3,95, 10060 Candiolo, Italy; im3D S.p.A., Turin, Italy. gabriella.iussich@ircc.it
authors: Gabriella
authors: G
authors: Iussich
authors: Loredana
authors: L
authors: Correale
authors: Carlo
authors: C
authors: Senore
authors: Nereo
authors: N
authors: Segnan
authors: Andrea
authors: A
authors: Laghi
authors: Franco
authors: F
authors: Iafrate
authors: Delia
authors: D
authors: Campanella
authors: Emanuele
authors: E
authors: Neri
authors: Francesca
authors: F
authors: Cerri
authors: Cesare
authors: C
authors: Hassan
authors: Daniele
authors: D
authors: Regge
mesh_terms: D023881:Colonography, Computed Tomographic / Q000706:statistics & numerical data*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000706:statistics & numerical data*; D010865:Pilot Projects; D015995:Prevalence; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity