Introduction: High-resolution computed tomography (HRCT) appearance including low attenuation area is one of the most important indices to evaluate severity of diffuse cystic lung diseases (DCLDs) including lymphangioleiomyomatosis (LAM), Birt-Hogg-Dubé syndrome (BHD) and Lymphatic interstitial lung disease (LIP). Another important evaluation for severity is pulmonary function tests (PFTs). Recently, quantitative HRCT analysis is used for diagnosis and measuring treatment effectiveness in LAM. However, there are few reports on the correlation between PFTs and HRCT using quantitative analysis in DCLDs.

Aims and objectives: The aim of this study was to assess the utility of automated 3D cyst analysis in DCLDs and correlation to PFTs.

Methods: 35 patients were included, eighteen LAM patients, ten BHD patients, seven LIP patients. HRCT images were interrogated using CT Pulmonary 3D tool on SyngoVia post-processing software (Siemens Healthineers, Erlangen, Germany). Imaging slices were 3mm or less. A cut of range of -900 to -950 Hounsfield Units were used for calculating attenuation area. The measurements of PFTs were set to meet the ATS/ERS instrument quality control standards.

Results: We found correlations between the HRCT parameters and PFT. Among these parameters, total lung attenuation volume (tLAV) and FEV1% predicted had the strongest correlations (r= -0.5, p< 0.01). FVC% predicted and FEV1/FVC% also correlated (r= 0.34, p= 0.05, r= -0.46, p<0.01). Interestingly, DLco didn?t correlate with cyst volume (r= 0.02).

Conclusion: Quantitative 3D HRCT analysis may be helpful tool for the assessment of disease severity in DCLD, this needs to be verified in larger population of DCLDs.