Lung Fibrosis Conventional and Molecular Imaging Diagnosis Update

Interstitial lung diseases are one of life-threatening conditions with high morbidity and mortality. Lung biopsy is the “gold standard” to diagnose, grade, and stage lung fibrosis, but lung biopsy has limitations in the diagnosis of early-stage lung fibrosis because clinically neither used as the first choice nor as routine diagnosis technique. Lung biopsy is also limitations of invasiveness, cost, sampling variability, inter-observer variability, and the dynamic process of fibrosis. More and more evidence has demonstrated that stages of lung fibrosis are reversible if the injury and risk factors are removed before progression to end-stage lung fibrosis. Developing safe, effective, and reliable non-invasive assessment modalities is clinically required to detect early-stage lung fibrosis and to manage it precisely in personalized medicine. Conventional imaging methods including ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) are useful in assessing advanced lung disease, including fibrotic scar in the lung by visualizing morphological and structural changes. Functional imaging techniques are useful for assessing moderate to advanced lung fibrosis using MR elastography (MRE), US elastography, and CT perfusion. MRE is considered the most accurate noninvasive imaging technique, and US elastography is currently the most widely used noninvasive means. However, these modalities are less accurate in early-stage lung fibrosis and some artifactual factors affect the accuracy of these techniques. Molecular imaging techniques of 18Ffluoroproline and other radiotracers are target-specific imaging that has the potential to accurately diagnose early-stage liver and lung fibrosis. We provide an overview of recent advances in molecular imaging for the diagnosis and staging of lung fibrosis which will enable clinicians and researchers to detect early-stage lung fibrosis, monitor the progression of disease and potentially reverse lung fibrosis. We compare the promising technologies with conventional and functional imaging and assess the utility of molecular imaging in precision and personalized clinical medicine in the early stages of lung fibrosis.