title: Interobserver agreement in the interpretation of outpatient head CT scans in an academic neuroradiology practice.
abstract: OBJECTIVE
  The repeatability of head CT interpretations may be studied in different contexts: in peer-review quality assurance interventions or in interobserver agreement studies. We assessed the agreement between double-blind reports of outpatient CT scans in a routine academic practice.
  
  
  METHODS
  Outpatient head CT scans (119 patients) were randomly selected to be read twice in a blinded fashion by 8 neuroradiologists practicing in an academic institution during 1 year. Nonstandardized reports were analyzed to extract 4 items (answer to the clinical question, major findings, incidental findings, recommendations for further investigations) from each report, to identify agreement or discrepancies (classified as class 2 [mentioned or not mentioned or contradictions between reports], class 1 [mentioned in both reports but diverging in location or severity], 0 [concordant], or not applicable), according to a standardized data-extraction form. Agreement regarding the presence or absence of clinically significant or incidental findings was studied with κ statistics.
  
  
  RESULTS
  The interobserver agreement regarding head CT studies with positive and negative results for clinically pertinent findings was 0.86 (0.77-0.95), but concordance was only 75.6% (67.2%-82.5%). Class 2 discrepancy was found in 15.1%; class 1 discrepancy, in 9.2% of cases. The κ value for reporting incidental findings was 0.59 (0.45-0.74), with class 2 discrepancy in 29.4% of cases. Most discrepancies did not impact the clinical management of patients.
  
  
  CONCLUSIONS
  Discrepancies in double-blind interpretations of head CT examinations were more common than reported in peer-review quality assurance programs.
authors: From the Department of Radiology (G.G., C.A.S., F.G., J.R.), Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital, Montreal, Quebec, Canada.
authors: G
authors: G
authors: Guérin
authors: Laboratory of Interventional Neuroradiology (S.J., J.R.), Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital Research Centre, Montreal, Quebec, Canada.
authors: S
authors: S
authors: Jamali
authors: From the Department of Radiology (G.G., C.A.S., F.G., J.R.), Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital, Montreal, Quebec, Canada.
authors: C A
authors: CA
authors: Soto
authors: From the Department of Radiology (G.G., C.A.S., F.G., J.R.), Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital, Montreal, Quebec, Canada.
authors: F
authors: F
authors: Guilbert
authors: From the Department of Radiology (G.G., C.A.S., F.G., J.R.), Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital, Montreal, Quebec, Canada Laboratory of Interventional Neuroradiology (S.J., J.R.), Centre Hospitalier de l'Université de Montréal, Notre-Dame Hospital Research Centre, Montreal, Quebec, Canada. jean.raymond@umontreal.ca.
authors: J
authors: J
authors: Raymond
mesh_terms: D000328:Adult; D000368:Aged; D001927:Brain Diseases / Q000000981:diagnostic imaging*; D004311:Double-Blind Method; D005260:Female; D006257:Head; D006801:Humans; D008297:Male; D008875:Middle Aged; D009462:Neurology / Q000592:standards*; D015588:Observer Variation; D010045:Outpatients; D010820:Physicians; D014057:Tomography, X-Ray Computed / Q000379:methods