Quantitative validation of the severity of emphysema by multi-detector CT

Abstract

Objectives: To determine whether MDCT reflects the severity of chronic obstructive pulmonary disease (COPD) compared to the pulmonary function tests (PFTs). Patients and methods: A prospective study included 63 COPD patients. Spirometry was done and included forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and the ratio of forced expiratory volume in 1 s over forced vital capacity (FEV1/FVC). Patients were grouped according to GOLD guidelines. MDCT examinations were obtained during full inspiration. The extent of emphysema was quantified by using dedicated software. −950 Hounsfield units (HU) used as the percentage of low-attenuation (%LA) emphysematous areas. Statistical study between PFTs, and CT emphysema extent was performed. Results: The study included 26 females and 37 males with a mean age of 53 years. A moderate significant relationship was found between lung volume less than −950 HU and FVC, FEV1, and FEV1/FVC (p < 0.001). Pulmonary function tests revealed that 23.8% had mild restrictive defect, 14.3% had moderate obstructive defect and 61.9% had severe obstructive defect. A good correlation was observed between the quantitative assessments for the lower lung regions with −950 HU (%LA) and pulmonary function variables (p < 0.001). Conclusion: MDCT results are significantly related to the data of PFTs for defining the severity of emphysema.

Keywords

• MDCT
• COPD
• Emphysema
• %LA
• PFTs