A1ATD is a genetic disease characterized by the presence of emphysema in the lungs. CT scan densitometry has emerged as the most sensitive non-invasive method for detecting and quantifying emphysema. Despite this, it has some limitations that preclude its use in follow-up. The purpose of this study was to evaluate if the extent of emphysema determined by CT scan densitometry could be assessed by LFT, which have less limitations.
In this prospective study, A1ATD patients underwent a CT scan to determine emphysema extent and contemporary LFT. Emphysema extent determined by CT scan and LFT parameters (FEV1, FEV1/FVC, FEF25–75%, TLC, RV, RV/TLC, FRC, DLCO, KLCO, pO2) were tested by Pearson correlation coefficient and multiple linear regression analysis.
31 patients (51,6% males, age 45 ± 16,3 years) with various A1ATD phenotypes were evaluated. Emphysema extent ranged from 0% to 44,39%. Except for TLC, RV/TLC and FRC all other variables correlated significantly with emphysema extent. After performing a stepwise multiple regression analysis, FEV1/FVC, FEF25–75% and DLCO were the only variables retained. The multiple regression model explained 91,8% of the variability of emphysema extent measured by CT scan.
In our study, the combination of FEV1/FVC, FEF25–75% and DLCO measurement provided a good estimate of the extent of emphysema as measured by CT scan in A1ATD patients.
Although this model has to be tested in patients other than the ones from which it was generated, if it proves to be valid, it will allow a good estimate of emphysema extent for the follow up of patients with A1ATD, without exposure to radiation.
Ana Filipa Costa, No Financial Disclosure Information; No Product/Research Disclosure Information