PURPOSE: High-resolution CT scans are increasingly important in the evaluation of COPD. The LTRC is a repository of clinical, physiologic and radiologic data including radiologist semi-quantitative assessment of disease and quantitative measures on volumetric CT scans. We hypothesize a stronger correlation between automated quantitative results than visual assessment to physiologic parameters and quality of life measures in the LTRC cohort of COPD patients.
METHODS: The LTRC database was utilized to compare emphysema measures with physiologic parameters for subjects with diagnosis of COPD or control subjects undergoing resection of suspected lung malignancy, lung volume reduction surgery or lung transplantation. Radiological assessment included emphysema scoring of 12 regions on each scan using a 5-point scale and automated quantification of % emphysema with a threshold of -950HU. Clinical assessment included spirometry, lung volumes, DLCO, smoking history, 6-minute walk and questionnaires including SGRQ and SF-12. Spearman Correlation coefficient between radiologist scoring, emphysema % and clinical parameters were calculated.
RESULTS: The study included 363 patients with a diagnosis of COPD (298) or control (65). Scoring of emphysema by a radiologist was highly correlated with quantitative emphysema score (r = 0.864 p < .0001). Radiologist score and quantitative % emphysema both equally well correlated with multiple physiologic parameters, including FEV1, DLCO, the 6-minute walk distance, and SF-12 physical and SGRQ responses.
CONCLUSION: Visual and quantitative assessment of disease features on CT correlate with quality of life assessment and physiological measures used to assess COPD severity. Automated quantitative measures of parenchymal emphysema are strongly correlated with visual assessment by a radiologist. The LTRC repository contains a wealth of data that can be utilized to examine novel clinical/physiologic/radiographic relationships while allowing correlation with tissue and blood based analyses.
CLINICAL IMPLICATIONS: Since quantitative CT measures highly correlate with both radiologic, physiologic and quality of life measures, quantitative analysis may be used as an objective, reproducible proxy for subjective testing in clinical practice or clinical trials.
DISCLOSURE: Colin Segovis, No Financial Disclosure Information; No Product/Research Disclosure Information