Imaging in idiopathic pulmonary fibrosis: diagnosis and mimics

Abstract

Idiopathic pulmonary fibrosis is a chronic disease of unknown etiology that usually has a progressive course and is commonly associated with a poor prognosis. The main symptoms of idiopathic pulmonary fibrosis, including progressive dyspnea and dry cough, are often nonspecific. Chest high-resolution computed tomography is the primary modality used in the initial assessment of patients with suspected idiopathic pulmonary fibrosis and may have considerable influence on subsequent management decisions. The main role of computed tomography is to distinguish chronic fibrosing lung diseases with a usual interstitial pneumonia pattern from those presenting with a non-usual interstitial pneumonia pattern, suggesting an alternative diagnosis when possible. A usual interstitial pneumonia pattern on chest tomography is characterized by the presence subpleural and basal predominance, reticular abnormality honeycombing with or without traction bronchiectasis, and the absence of features suggestive of an alternative diagnosis. Idiopathic pulmonary fibrosis can be diagnosed according to clinical and radiological criteria in approximately 66.6% of cases. Confirmation of an idiopathic pulmonary fibrosis diagnosis is challenging, requiring the exclusion of pulmonary fibroses with known causes, such as asbestosis, connective tissue diseases, drug exposure, chronic hypersensitivity pneumonitis, and other forms of idiopathic interstitial pneumonitis. The histopathological hallmark of usual interstitial pneumonia is a heterogeneous appearance, characterized by areas of fibrosis with scarring and honeycombing alternating with areas of less affected or normal parenchyma. The aim of this article was to review the clinical, radiological, and pathological features of idiopathic pulmonary fibrosis and of diseases that might mimic idiopathic pulmonary fibrosis presentation.

Practical Imaging Interpretation in Patients Suspected of Having Idiopathic Pulmonary Fibrosis: Official Recommendations from the Radiology Working Group of the Pulmonary Fibrosis Foundation

“…Normal radiographs were described in older literature (1970s) in 10%-15% of patients with ILD, and this number is probably higher in clinical practice today given advances in cross-sectional imaging to detect very mild or early disease (10). Characterizing ILD to the extent necessary to guide diagnosis and further management is also usually not possible on radiographs, and patients with obesity or underinflation can cause false-positive radiograph interpretation due to the perception of increased interstitial markings in those patients (2). Chest radiographs are still frequently used to evaluate patients with pulmonary fibrosis for alternative diagnoses such as pneumonia or pneumothorax.…”

“…Thin-Section CT Thin-section CT, in which images are reconstructed with thin sections and high-spatial-frequency algorithms, is recommended to optimally image the lung interstitium and to characterize parenchymal abnormalities. Technical factors used for the thin-section CT scanning protocol are important and can help prevent diagnostic errors when properly set (2,3,6). While high-spatial-resolution reconstruction is important, excessive edge enhancement can result in image Because the fine detail of the lung parenchyma is of paramount importance in thin-section CT scans, technologists should review scans immediately after acquisition and consider repeat scanning for any portions of the study that are compromised by patient or respiratory motion or inadequate inspiration (2,3).…”

“…Technical factors used for the thin-section CT scanning protocol are important and can help prevent diagnostic errors when properly set (2,3,6). While high-spatial-resolution reconstruction is important, excessive edge enhancement can result in image Because the fine detail of the lung parenchyma is of paramount importance in thin-section CT scans, technologists should review scans immediately after acquisition and consider repeat scanning for any portions of the study that are compromised by patient or respiratory motion or inadequate inspiration (2,3). Respiratory motion (and sometimes unavoidable cardiac motion) can produce pulsation or star artifact, particularly in the lingula.…”

“…IPF is a progressive chronic interstitial fibrotic lung disease of unknown etiology (1). Risk factors include older age, family history, chronic gastrointestinal reflux, smoking, and some environmental exposures (2)(3)(4)(5)(6). Typical clinical manifestations are nonspecific and include chronic dyspnea, dry cough, fatigue, lower lung crackles at physical examination, and digital clubbing.…”

Sodium Houttuyfonate Inhibits Bleomycin Induced Pulmonary Fibrosis in Mice

“…Some unknown factors can also trigger idiopathic pulmonary fibrosis (IPF), which is one of the most common pulmonary fibrotic conditions, aberrant activation of alveolar epithelial cells and fibroblasts in an aging lung is the key to the pathogenesis of IPF (Selman and Pardo, 2014). This progressive and fatal disease is chronic and characterized by bilateral pulmonary interstitial infiltration, restriction on pulmonary function testing, and progressive dyspnea with respiratory failure (Degryse and Lawson, 2011;Hochhegger et al, 2019). Pulmonary wound-healing responses following lung damage include inflammation and repair, often accompanied by the rise of chemokines, cytokines and growth factors.…”