CT Analysis of the Anterior Mediastinum in Idiopathic Pulmonary Fibrosis and Nonspecific Interstitial Pneumonia

Abstract

ObjectiveWe wanted to determine whether the amount and shape of the anterior mediastinal fat in the patients suffering with usual interstitial pneumonia (UIP) or nonspecific interstitial pneumonia (NSIP) was different from those of the normal control group.Materials and MethodsWe selected patients who suffered with UIP (n = 26) and NSIP (n = 26) who had undergone CT scans. Twenty-six controls were selected from individuals with normal CT findings and normal pulmonary function tests. All three groups (n = 78) were individually matched for age and gender. The amounts of anterior mediastinal fat, and the retrosternal anteroposterior (AP) and transverse dimensions of the anterior mediastinal fat were compared by one-way analysis of variance and Bonferroni's test. The shapes of the anterior mediastinum were compared using the Chi-square test. Exact logistic regression analysis and polychotomous logistic regression analysis were employed to assess whether the patients with NSIP or UIP had a tendency to show a convex shape of their anterior mediastinal fat.ResultsThe amount of anterior mediastinal fat was not different among the three groups (p = 0.175). For the UIP patients, the retrosternal AP dimension of the anterior mediastinal fat was shorter (p = 0.037) and the transverse dimension of the anterior mediastinal fat was longer (p = 0.001) than those of the normal control group. For the NSIP patients, only the transverse dimension was significantly longer than those of the normal control group (p < 0.001). The convex shape of the anterior mediastinum was predictive of NSIP (OR = 19.7, CI 3.32 -∞, p < 0.001) and UIP (OR = 24.42, CI 4.06 -∞, p < 0.001).ConclusionFor UIP patients, the retrosternal AP and transverse dimensions are different from those of normal individuals, whereas the amounts of anterior mediastinal fat are similar. UIP and NSIP patients have a tendency to have a convex shape of their anterior mediastinal fat.

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

“…To exclude other factors that might change the shape of the anterior mediastinal fat, patients with history of tuberculosis, empyema, connective tissue diseases, exposure to organic or inorganic dust or toxic fumes, Cushing disease, asthma or any other diseases requiring steroid medication were excluded from the study population. Patients who had been treated with steroids before HRCT were excluded for the same reason [4]. Our Ethics institutional review board approved this study.…”

“…The shape of the anterior mediastinal fat was categorized concave, flat or convex at the level of the main pulmonary trunk. The anteroposterior (AP) (from the posterior wall of the sternum to the anterior wall of the ascending aorta) and transverse dimensions (the width of the posterior wall of the sternum in contact with the anterior mediastinal fat) at the level of the main pulmonary trunk were also measured [4].…”

“…Other causes of lung scarring can similarly widen the mediastinum. Mediastinal widening can be seen in idiopathic pulmonary fibrosis (IPF) [4]. Unfortunately, proper description of the shape of anterior mediastinal fat in IPF is not widely studied [4].…”

“…Mediastinal widening can be seen in idiopathic pulmonary fibrosis (IPF) [4]. Unfortunately, proper description of the shape of anterior mediastinal fat in IPF is not widely studied [4]. Moreover, to the best of our knowledge, its relation to PFTs and HRCT score has never been assigned.…”

A comparison of idiopathic pulmonary fibrosis and chronic hypersensitivity pneumonia in terms of anterior mediastinal fat properties

“…The anterior mediastinum has a structure that can be affected by various pathological conditions and easily adapt to these changes (10). The shape and physical properties of the anterior mediastinum can be easily affected by inflammatory lung diseases, tuberculosis, empyema, radiotherapy, chronic fibrotic lung diseases, previous surgery, and after steroid therapy (11)(12)(13). There are studies in which the fat ratio in the body is evaluated (the skeletal muscle index) in diagnostic processes (14).…”