title: Diagnostic yield of recommendations for chest CT examination prompted by outpatient chest radiographic findings.
abstract: OBJECTIVE
  To evaluate the diagnostic yield of recommended chest computed tomography (CT) prompted by abnormalities detected on outpatient chest radiographic images.
  
  
  METHODS
  This HIPAA-compliant study had institutional review board approval; informed consent was waived. Reports of all outpatient chest radiographic examinations performed at a large academic center during 2008 (n = 29 138) were queried to identify studies that included a recommendation for a chest CT imaging. The radiology information system was queried for these patients to determine if a chest CT examination was obtained within 1 year of the index radiographic examination that contained the recommendation. For chest CT examinations obtained within 1 year of the index chest radiographic examination and that met inclusion criteria, chest CT images were reviewed to determine if there was an abnormality that corresponded to the chest radiographic finding that prompted the recommendation. All corresponding abnormalities were categorized as clinically relevant or not clinically relevant, based on whether further work-up or treatment was warranted. Groups were compared by using t test and Fisher exact test with a Bonferroni correction applied for multiple comparisons.
  
  
  RESULTS
  There were 4.5% (1316 of 29138 [95% confidence interval {CI}: 4.3%, 4.8%]) of outpatient chest radiographic examinations that contained a recommendation for chest CT examination, and increasing patient age (P < .001) and positive smoking history (P = .001) were associated with increased likelihood of a recommendation for chest CT examination. Of patients within this subset who met inclusion criteria, 65.4% (691 of 1057 [95% CI: 62.4%, 68.2%) underwent a chest CT examination within the year after the index chest radiographic examination. Clinically relevant corresponding abnormalities were present on chest CT images in 41.4% (286 of 691 [95% CI: 37.7%, 45.2%]) of cases, nonclinically relevant corresponding abnormalities in 20.6% (142 of 691 [95% CI: 17.6%, 23.8%]) of cases, and no corresponding abnormalities in 38.1% (263 of 691 [95% CI: 34.4%, 41.8%]) of cases. Newly diagnosed, biopsy-proven malignancies were detected in 8.1% (56 of 691 [95% CI: 6.2%, 10.4%]) of cases.
  
  
  CONCLUSIONS
  A radiologist recommendation for chest CT to evaluate an abnormal finding on an outpatient chest radiographic examination has a high yield of clinically relevant findings.
authors.affiliation: From the Department of Radiology (H.B.H., M.D.G., C.C.W., E.F.H., P.V.P., J.O.S., T.K.A.) and Institute for Technology Assessment (P.V.P.), Massachusetts General Hospital, Harvard Medical School, 175 Cambridge St, Suite 200, Boston, MA 02114; Department of Biostatistics, Harvard School of Public Health, Cambridge, Mass (J.Z.); and Advanced Medical Imaging, Denver, Colo (M.S.C.).
authors.forename: H Benjamin
authors.initials: HB
authors.lastname: Harvey
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Gilman
authors.forename: Carol C
authors.initials: CC
authors.lastname: Wu
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Cushing
authors.forename: Elkan F
authors.initials: EF
authors.lastname: Halpern
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Pari V
authors.initials: PV
authors.lastname: Pandharipande
authors.forename: Jo-Anne O
authors.initials: JA
authors.lastname: Shepard
authors.forename: Tarik K
authors.initials: TK
authors.lastname: Alkasab
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D001706:Biopsy; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D008404:Massachusetts; D008875:Middle Aged; D013902:Radiography, Thoracic; D012017:Referral and Consultation / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media