Similarity of chest X-ray and thermal imaging of focal pneumonia: a randomised proof of concept study at a large urban teaching hospital

Objective To assess the diagnostic accuracy of thermal imaging (TI) in the setting of focal consolidative pneumonia with chest X-ray (CXR) as the gold standard. Setting A large, 973-bed teaching hospital in Boston, Massachusetts. Participants 47 patients enrolled, 15 in a training set, 32 in a test set. Age range 10 months to 82 years (median=50 years). Materials and methods Subjects received CXR with subsequent TI within 4 hours of each other. CXR and TI were assessed in blinded random order. Presence of focal opacity (pneumonia) on CXR, the outcome parameter, was recorded. For TI, presence of area(s) of increased heat (pneumonia) was recorded. Fisher’s exact test was used to assess the significance of the correlations of positive findings in the same anatomical region. Results With TI compared with the CXR (the outcome parameter), sensitivity was 80.0% (95% CIs 29.9% to 98.9%), specificity was 57.7% (95% CI 37.2% to 76.0%). Positive predictive value of TI was 26.7% (95% CI 8.9% to55.2%) and its negative predictive value was 93.8% (95% CI 67.7% to 99.7%). Conclusions This feasibility study confirms proof of concept that chest TI is consistent with CXR in suggesting similarly localised focal pneumonia with high sensitivity and negative predictive value. Further investigation of TI as a point-of-care imaging modality is warranted.