Anterior Mediastinal Fat Changes in Idiopathic Pulmonary Fibrosis: A Preliminary Study

Background: The mediastinum is composed primarily of fatty tissue that is surrounded by the lungs bilaterally. There is a lack in the published literature in studying changes in mediastinal fat in idiopathic pulmonary fibrosis (IPF). The purpose of this study was to determine whether the shape and dimensions of the anterior mediastinal fat in patients with IPF are different from that of a normal control group and to correlate the changes with disease severity. Design and Setting: This prospective case control study was done at the chest department of Assiut University Hospital on IPF patients from May 2010-September 2012. A questionnaire containing questions such as age, sex, clinical findings, high resolution computerized tomography (HRCT) score and pulmonary function tests (PFTs) was filled for patients and normal controls. Results: The IPF retrosternal AP dimension was significantly shorter (p = 0.03) and the transverse dimension was longer (p = 0.001) than that in the normal control group. The convex shape of the anterior mediastinum was predictive of IPF (p = 0.001), whereas concave shape was predictive of normal controls (p = 0.001). The change in anteroposterior diameter (AP) and transverse diameters showed significant correlation with the changes in FVC, DLCO and HRCT score. Conclusions: IPF patients had reduced retrosternal AP and increased transverse dimensions than those of the controls with convex shape of their anterior mediastinal fat. Changes in anterior mediastinal fat dimensions are correlated with lower FVC, DLCO and higher HRCT score. A larger sample size, better multicenteric study is needed to confirm the results of this study.