Monday, March 18, 2019 | 18:00 CET
MRI of the Lung: Protocols and Indications
Jürgen Biederer, Sehheim-Jugenheim/DE

Description
The traditional workhorses for thoracic imaging in diagnostic radiology are Chest X-ray, computed tomography (CT) and in some cases lung ultrasound (US). Only more recently MRI has joined the “zoo” of available lung imaging modalities. However, many radiologists are still reluctant to use this new modality being not familiar with its application and diagnostic scope. For a start, it is therefore worth a while having a closer look at imaging protocols and useful indications for the method in this webinar.
Setting up a protocol tree for lung imaging with MRI is straightforward using standard sequences for different pathologies. Customized lung imaging protocols with suitable pre- sets may be already available with the MR equipment or are easy to implement. The basic protocol approach uses T2-w. fast spin echo (FSE) for infiltrates/soft lesions (1), T2-w. FSE with fat suppression for lymph nodes/bone lesions (2), Steady state free precession sequences (SSFP) for respiratory motion/lung vasculature (3) and T1-w. 3D gradient echo (3D-GRE) for nodules/masses and airways (4). Optional sequences comprise MR angiography, dynamic contrast enhancement (DCE) for lung/tumor perfusion and diffusion weighted imaging (DWI) for lymph nodes/lesion characterization. Examination times range from 15’ (standard) to 25’ (all options).
With these standardized protocols, the sensitivity of MRI for infiltrates is at least similar to X-ray and CT, lung nodule detection is superior to X-ray and slightly inferior to CT. Unique options for tissue characterization (exclusion of malignancy) and functional imaging capacities (perfusion, ventilation, respiratory motion) become available.
Given this, MRI may serve as a radiation-free alternative in patients who should not be exposed to ionizing radiation (children and young subjects, pregnant patients), e.g. as your first choice modality in patients with cystic fibrosis. It may well serve as an adjunct to other modalities for comprehensive lung imaging in COPD and some cases of interstitial lung diseases, e.g. sarcoidosis (dark lymph node sign). In young patients, it may well be used for the long term follow-up of malignancy (e.g. seminoma) or inflammatory disease (e.g. GPA/Wegener’s disease). As an adjunct or alternative to other modalities, MRI can be helpful in lung cancer staging and follow-up (differentiation of atelectasis and lung cancer) or the characterization of lung nodules (“actionable nodules” with contrast uptake, high NPV of nodules with no or low contrast uptake, fatty content in hamartoma). This even qualifies MRI as a potential tool for early detection of lung cancer, either as screening tool or for the further diagnostic work-up of detected lesions.

Learning objectives
This lecture is intended to
1) provide basic protocol suggestions for clinical lung MRI
2) make familiar with variations of this protocol for typical questions such as parenchymal, vascular or malignant diseases of the lung.
3) demonstrate the diagnostic scope of lung MRI for pathologies of lung parenchyma and airway disease
4) introduce MRI as potential first choice modality for imaging and follow up of pulmonary disease in young or pregnant patients and to
5) discuss the potential role of lung MRI as an alternative or adjunct to other modalities, e.g. in COPD or interstitial lung diseases