title: The value of digital tomosynthesis of the chest as a problem-solving tool for suspected pulmonary nodules and hilar lesions detected on chest radiography.
abstract: OBJECTIVE
  To assess the capability of digital tomosynthesis (DTS) of the chest compared to a postero-anterior (PA) and lateral chest radiograph (CXR) in the diagnosis of suspected but unconfirmed pulmonary nodules and hilar lesions detected on a CXR. Computed tomography (CT) was used as the reference standard.
  
  
  METHODS
  78 patients with suspected non-calcified pulmonary nodules or hilar lesions on their CXR were included in the study. Two radiologists, blinded to the history and CT, prospectively analysed the CXR (PA and lateral) and the DTS images using a picture archiving and communication workstation and were asked to designate one of two outcomes: true intrapulmonary lesion or false intrapulmonary lesion. A CT of the chest performed within 4 weeks of the CXR was used as the reference standard. Inter-observer agreement and time to report the modalities were calculated for CXR and DTS.
  
  
  RESULTS
  There were 34 true lesions confirmed on CT, 12 were hilar lesions and 22 were peripheral nodules. Of the 44 false lesions, 37 lesions were artefactual or due to composite shadow and 7 lesions were real but extrapulmonary simulating non-calcified intrapulmonary lesions. The PA and lateral CXR correctly classified 39/78 (50%) of the lesions, this improved to 75/78 (96%) with DTS. The sensitivity and specificity was 0.65 and 0.39 for CXR and 0.91 and 1 for DTS. Based on the DTS images, readers correctly classified all the false lesions but missed 3/34 true lesions. Two of the missed lesions were hilar in location and one was a peripheral nodule. All three missed lesions were incorrectly classified on DTS as composite shadow.
  
  
  CONCLUSIONS
  DTS improves diagnostic confidence when compared to a repeat PA and lateral CXR in the diagnosis of both suspected hilar lesions and pulmonary nodules detected on CXR. DTS is able to exclude most peripheral pulmonary nodules but caution and further studies are needed to assess its ability to exclude hilar lesions.
authors.affiliation: Peninsula Radiology Academy, William Prance Road, Plymouth PL65WR, UK. Electronic address: galeaangie@gmail.com.
authors.forename: Angela
authors.initials: A
authors.lastname: Galea
authors.affiliation: Plymouth Hospital NHS Trust, Plymouth PL68DH, UK. Electronic address: Paul.dubbins@nhs.net.
authors.forename: Paul
authors.initials: P
authors.lastname: Dubbins
authors.affiliation: Plymouth Hospital NHS Trust, Plymouth PL68DH, UK. Electronic address: richardriordan@nhs.net.
authors.forename: Richard
authors.initials: R
authors.lastname: Riordan
authors.affiliation: Plymouth Hospital NHS Trust, Plymouth PL68DH, UK. Electronic address: tarig.adlan@nhs.net.
authors.forename: Tarig
authors.initials: T
authors.lastname: Adlan
authors.affiliation: Plymouth Hospital NHS Trust, Plymouth PL68DH, UK. Electronic address: carl.roobotoom@nhs.net.
authors.forename: Carl
authors.initials: C
authors.lastname: Roobottom
authors.affiliation: Plymouth Hospital NHS Trust, Plymouth PL68DH, UK. Electronic address: davegay@nhs.net.
authors.forename: David
authors.initials: D
authors.lastname: Gay
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055613:Multiple Pulmonary Nodules / Q000000981:diagnostic imaging* / Q000473:pathology; D011856:Radiographic Image Enhancement; D013902:Radiography, Thoracic / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
keywords: Chest radiology; Digital tomosynthesis; Hilar lesions; Lung nodules