Pulmonary fibrosis: tissue characterization using late-enhanced MRI compared with unenhanced anatomic high-resolution CT

PURPOSE:We aimed to prospectively evaluate anatomic chest computed tomography (CT) with tissue characterization late gadolinium-enhanced magnetic resonance imaging (MRI) in the evaluation of pulmonary fibrosis (PF).METHODS:Twenty patients with idiopathic pulmonary fibrosis (IPF) and twelve control patients underwent late-enhanced MRI and high-resolution CT. Tissue characterization of PF was depicted using a segmented inversion-recovery turbo low-angle shot MRI sequence. Pulmonary arterial blood pool nulling was achieved by nulling main pulmonary artery signal. Images were read in random order by a blinded reader for presence and extent of overall PF (reticulation and honeycombing) at five anatomic levels. Overall extent of IPF was estimated to the nearest 5% as well as an evaluation of the ratios of IPF made up of reticulation and honeycombing. Overall grade of severity was dependent on the extent of reticulation and honeycombing.RESULTS:No control patient exhibited contrast enhancement on lung late-enhanced MRI. All IPF patients were identified with late-enhanced MRI. Mean signal intensity of the late-enhanced fibrotic lung was 31.8±10.6 vs. 10.5±1.6 for normal lung regions, P < 0.001, resulting in a percent elevation in signal intensity from PF of 204.8%±90.6 compared with the signal intensity of normal lung. The mean contrast-to-noise ratio was 22.8±10.7. Late-enhanced MRI correlated significantly with chest CT for the extent of PF (R=0.78, P = 0.001) but not for reticulation, honeycombing, or coarseness of reticulation or honeycombing.CONCLUSION:Tissue characterization of IPF is possible using inversion recovery sequence thoracic MRI

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

Fetal brain MRI: Neurometrics, Typical Diagnoses, and Resolving Common Dilemmas

This review presents a practical approach to imaging the fetal brain by MRI. Herein, we demonstrate how to measure brain structures and fluid spaces, and discuss the importance of comparing measurements to normative biometric references at a corresponding gestational age. We present some common imaging dilemmas of the technical aspects of fetal MRI with regards to typical regions of abnormality including the cerebrum, the ventricular system, and the posterior fossa, and discuss how to resolve them