title: Incidental imaging findings from routine chest CT used to identify subjects at high risk of future cardiovascular events.
abstract: OBJECTIVE
  To investigate the contribution of incidental findings at chest computed tomography (CT) in the detection of subjects at high risk for cardiovascular disease (CVD) by deriving and validating a CT-based prediction rule.
  
  
  METHODS
  This retrospective study was approved by the ethical review board of the primary participating facility, and informed consent was waived. The derivation cohort comprised 10 410 patients who underwent diagnostic chest CT for noncardiovascular indications. During a mean follow-up of 3.7 years (maximum, 7.0 years), 1148 CVD events (cases) were identified. By using a case-cohort approach, CT scans from the cases and from an approximately 10% random sample of the baseline cohort (n = 1366) were graded visually for several cardiovascular findings. Multivariable Cox proportional hazards analysis with backward elimination technique was used to derive the best-fitting parsimonious prediction model. External validation (discrimination, calibration, and risk stratification) was performed in a separate validation cohort (n = 1653).
  
  
  RESULTS
  The final model included patient age and sex, CT indication, left anterior descending coronary artery calcifications, mitral valve calcifications, descending aorta calcifications, and cardiac diameter. The model demonstrated good discriminative value, with a C statistic of 0.71 (95% confidence interval: 0.68, 0.74) and a good overall calibration, as assessed in the validation cohort. This imaging-based model allows accurate stratification of individuals into clinically relevant risk categories.
  
  
  CONCLUSIONS
  Structured reporting of incidental CT findings can mediate accurate stratification of individuals into clinically relevant risk categories and subsequently allow those at higher risk of future CVD events to be distinguished.
authors.affiliation: From the Julius Center for Health Sciences and Primary Care (P.M.J., D.E.G., Y.v.d.G.) and Department of Radiology (P.M.J., M.J.A.G., W.P.T.M.M., P.C.A.J.), University Medical Center Utrecht, Universiteitsweg 100, PO Box 85500, Room E 6.116, 3584 CG Utrecht, the Netherlands.
authors.forename: Pushpa M
authors.initials: PM
authors.lastname: Jairam
authors.forename: Martijn J A
authors.initials: MJ
authors.lastname: Gondrie
authors.forename: Diederick E
authors.initials: DE
authors.lastname: Grobbee
authors.forename: Willem P Th M
authors.initials: WP
authors.lastname: Mali
authors.forename: Peter C A
authors.initials: PC
authors.lastname: Jacobs
authors.forename: Yolanda
authors.initials: Y
authors.lastname: van der Graaf
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D009426:Netherlands / Q000453:epidemiology; D011379:Prognosis; D011860:Radiography, Abdominal / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*