Sarcoidosis HRCT subtypes and their relation to symptoms and lung function test results

The Scadding classification, based on chest X-rays is commonly used to assess the extent of lung involvement and long-term prognosis. Lung HRCT allows more precise definition of radiological subtypes. The literature currently provides limited data on the correlation between HRCT radiological signs and clinical features. <bold>Material and methods:</bold> Van den Heuvel classification based on detailed analysis of HRCT features was used to assess the radiological severity of 111 sarcoidosis patients. Results were evaluated in relation to fatigue (Fatigue Assessment Scale), dyspnea, cough and quality of life (Sarcoidosis Health Questionnaire). Lung function was assessed by spirometry and diffusion capacity. <bold>Results:</bold> Four most commonly observed radiological subtypes were defined: 1 – predominantly lympho-nodular, 2 - diffuse-nodular, 3 - central, 4 - fibrotic. Significant differences were found between the subtypes. Based on the analysis of radiological feature clusters, four groups (A, B, C, and D) were identified. The kappa test revealed minimal agreement between subtypes and cluster groups. One-way ANOVA modeling revealed the strongest association between Van den Heuvel scores and radiological subtypes (η2=0.62, p<0.0001). Radiological subtypes significantly explained models dependent on FEV1 (η2=0.30, p<0.0001), the presence of abnormal diffusion (η2=0.17, p=0.048) and spirometry (η2=0.15, p=0.024). Differences were demonstrated in the frequency of abnormal spirometry and diffusion among radiological subtypes (p=0.0017; p=0.0008). Clustering analysis demonstrated that the smallest distances occurred between subtypes 2 and 3. <bold>Conclusions:</bold> Radiological subtypes differ in terms of the severity of ventilation impairments.