title: Interobserver variability in retreatment decisions of recurrent and residual aneurysms.
abstract: OBJECTIVE
  The degree of variation in retreatment decisions for residual or recurrent aneurysms among endovascular therapists remains poorly defined. We performed a multireader study to determine what reader and patient variables contribute to this variation.
  
  
  METHODS
  Seven endovascular therapists (4 neuroradiologists, 3 neurosurgeons) independently reviewed 66 cases of patients treated with endovascular coil embolization for ruptured or unruptured aneurysm. Cases were rated on a 5-point scale recommending for whether to retreat and a recommended retreatment type. Reader agreement was assessed by intraclass correlation coefficient and by identifying cases with a "clinically meaningful difference" (a difference in score that would result in a difference in treatment). Variables that affect reader agreement and retreatment decisions were examined by using the Wilcoxon signed-rank test, Pearson χ(2) test, and linear regression.
  
  
  RESULTS
  Overall interobserver variability for decision to retreat was moderate (ICC = 0.50; 95% CI, 0.40-0.61). Clinically meaningful differences between at least 2 readers were present in 61% of cases and were significantly more common among neuroradiologists than neurosurgeons (P = .0007). Neurosurgeons were more likely to recommend "definitely retreat" than neuroradiologists (P < .0001). Previously ruptured aneurysms, larger remnant size, and younger patients were associated with more retreat recommendations. Interobserver variability regarding retreatment type was fair overall 0.25 (95% CI, 0.14-0.41) but poor for experienced readers 0.14 (95% CI, 0-0.34).
  
  
  CONCLUSIONS
  There is a large amount of interobserver variability regarding the decision to retreat an aneurysm and the type of retreatment. This variability must be reduced to increase consistency in these subjective outcome measurements.
authors.affiliation: Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, MN 55905, USA. mcdonald.jennifer@mayo.edu
authors.forename: J S
authors.initials: JS
authors.lastname: McDonald
authors.forename: R E
authors.initials: RE
authors.lastname: Carter
authors.forename: K F
authors.initials: KF
authors.lastname: Layton
authors.forename: J
authors.initials: J
authors.lastname: Mocco
authors.forename: J B
authors.initials: JB
authors.lastname: Madigan
authors.forename: R G
authors.initials: RG
authors.lastname: Tawk
authors.forename: R A
authors.initials: RA
authors.lastname: Hanel
authors.forename: S S
authors.initials: SS
authors.lastname: Roy
authors.forename: H J
authors.initials: HJ
authors.lastname: Cloft
authors.forename: A M
authors.initials: AM
authors.lastname: Klunder
authors.forename: S H
authors.initials: SH
authors.lastname: Suh
authors.forename: D F
authors.initials: DF
authors.lastname: Kallmes
mesh_terms: D000368:Aged; D002533:Cerebral Angiography / Q000706:statistics & numerical data*; D003657:Decision Making; D057510:Endovascular Procedures / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D015588:Observer Variation; D015995:Prevalence; D011379:Prognosis; D012008:Recurrence; D012086:Reoperation / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity