Assosiaciation of diaphragm thickness, diaphragm density and pectoralis major muscle area measured on chest ct with fibrosis severity in idiopatic pulmonary fibrosis patients

Purpose: The aim of this study is to compare diaphragm thickness (DT), diaphragm density (DD), and pectoralis major muscle area (PMMA) in patients with idiopathic pulmonary fibrosis (IPF) with the control group and to investigate the relationship between lung fibrosis severity, DT, DD, and PMMA. Materials and methods: Contrast-enhanced chest CT images of 57 patients with IPF and 32 healthy individuals were examined. The ratio of fibrotic lung parenchyma to total lung volume was calculated as a percentage. DT and DD values were recorded at the level of celiac artery origin. PMMA was measured at the level of the upper border of the aortic arch. T4 vertebral corpus area was used for index values. Results: In the patient group, right DT (p<0.001), left DT (p=0.001), mean DT (p<0.001), right DT index (p<0.001), left DT index (p<0.001), mean DT index (p< 0.001), right DD (p=0.001), left DD (p=0.019) and mean DD (p=0.009) were significantly lower than the control group. A significant negative correlation was detected between fibrosis percentage and left DT, mean DT, left DT index, mean DT index, right DD, left DD and mean DD. The mean DT (AUC=0.729) and mean DT index (AUC=0.734) showed moderate performance in predicting moderate/severe fibrosis. Conclusion: The diaphragm is thinner, and the diaphragm density is lower in patients with IPF than in healthy individuals. As the severity of fibrosis in the lung parenchyma increases, DT and DD decrease. Fibrosis severity may be predicted by using CT imaging performed during diagnosis or follow-up in IPF patients.