RT Journal Article
SR Electronic
T1 The use of pretest probability increases the value of high-resolution CT in diagnosing usual interstitial pneumonia
JF Thorax
JO Thorax
FD BMJ Publishing Group Ltd and British Thoracic Society
SP 424
OP 429
DO 10.1136/thoraxjnl-2016-209671
VO 72
IS 5
A1 Robert Brownell
A1 Teng Moua
A1 Travis S Henry
A1 Brett M Elicker
A1 Darin White
A1 Eric Vittinghoff
A1 Kirk D Jones
A1 Anatoly Urisman
A1 Carlos Aravena
A1 Kerri A Johannson
A1 Jeffrey A Golden
A1 Talmadge E King, Jr
A1 Paul J Wolters
A1 Harold R Collard
A1 Brett Ley
YR 2017
UL http://thorax.bmj.com/content/72/5/424.abstract
AB Background Recent studies have suggested that non-definitive patterns on high-resolution CT (HRCT) scan provide sufficient diagnostic specificity to forgo surgical lung biopsy in the diagnosis of idiopathic pulmonary fibrosis (IPF). The objective of this study was to determine test characteristics of non-definitive HRCT patterns for identifying histopathological usual interstitial pneumonia (UIP).Methods Patients with biopsy-proven interstitial lung disease (ILD) and non-definitive HRCT scans were identified from two academic ILD centres. Test characteristics for HRCT patterns as predictors of UIP on surgical lung biopsy were derived and validated in independent cohorts.Results In the derivation cohort, 64/385 (17%) had possible UIP pattern on HRCT; 321/385 (83%) had inconsistent with UIP pattern. 113/385 (29%) patients had histopathological UIP pattern in the derivation cohort. Possible UIP pattern had a specificity of 91.2% (95% CI 87.2% to 94.3%) and a positive predictive value (PPV) of 62.5% (95% CI 49.5% to 74.3%) for UIP pattern on surgical lung biopsy. The addition of age, sex and total traction bronchiectasis score improved the PPV. Inconsistent with UIP pattern demonstrated poor PPV (22.7%, 95% CI 18.3% to 27.7%). HRCT pattern specificity was nearly identical in the validation cohort (92.7%, 95% CI 82.4% to 98.0%). The substantially higher prevalence of UIP pattern in the validation cohort improved the PPV of HRCT patterns.Conclusions A possible UIP pattern on HRCT has high specificity for UIP on surgical lung biopsy, but PPV is highly dependent on underlying prevalence. Adding clinical and radiographic features to possible UIP pattern on HRCT may provide sufficient probability of histopathological UIP across prevalence ranges to change clinical decision-making.