Tissue characerisation of lung fibrosis: assessment with late-enhancement magnetic resonance imaging

Accurate depiction and quantification of lung fibrosis is important for diagnosis, treatment and prognosis of conditions that cause loss of function by fibrotic pulmonary process.The gold-standard non-invasive imaging test of pulmonary fibrosis remains chest computed tomography (CT), which relies on the anatomical depiction of fibrosis, characterised by increased septal lines, traction bronchiectasis and honeycombing as the hallmarks of pulmonary fibrosis.Magnetic resonance (MR), has the potential to characterise different tissues, based on composition and relaxation parameters, without the drawback of ionizing radiation. This ability to differentiate based on tissue type represents a different paradigm of pulmonary fibrosis imaging, based on a tissue characterization model rather than a purely anatomical one.Late gadolinium enhancement (LE) has been used in cardiac MR imaging to detect and quantify myocardial fibrosis, whose enlarged extracellular space provides a nidus for gadolinium to concentrate and thus produce a signal on T1 based imaging.We hypothesize that the same rationale will allow depiction of lung fibrosis given its tissue histopathological characteristics, and the studies that follow will test this hypothesis in two conditions with this pathological substrate, idiopathic pulmonary fibrosis and pulmonary sarcoidosis.If we can depict pulmonary fibrosis using this MR sequence, it would represent a major advance in the imaging of lung fibrosis in sarcoidosis and idiopathic pulmonary fibrosis (IPF), and open up the door to the possibility of specific contrast imaging markers linked to gadolinium that might bind to fibrotic receptors, thus increasing the specificity of imaging in these disorders