MRI of Lung

Abstract

MRI is emerging as a valuable lung imaging modality, together with x-ray and CT. It offers a unique combination of morphological and functional information in a single examination without any radiation burden to the patient. With a comprehensive protocol approach as proposed, MRI of the lung can be readily performed on most state-of-the-art 1.5-T MRI scanners. Breath-hold imaging or triggered acquisitions, together with advanced sequence technology (e.g. parallel imaging and rotating phase encoding), make image quality reasonably robust against artefacts induced by respiratory motion and heart action. Parts of the protocol produce images of diagnostic quality even in uncooperative patients. This allows for appreciation of the specific features of lung MRI related to its excellent soft tissue contrast and functional imaging capacities . The sensitivity of these protocols for infiltrates is at least similar to X-ray and CT. In lung nodule detection, MRI is superior to X-ray and almost as sensitive as CT. MRI can be of added value in patients with locally or systemically advanced lung cancer when the decision for surgery is critical. Whole-body MRI also has the potential to replace more invasive diagnostic procedures in a lung cancer work-up. (4) Much work has been performed on COPD and CF,and functional techniques are readily transferable to other lung conditions,such as interstitial lung diseases . A dedicated selection of sequences for imaging lung vasculature allows for the detection of pulmonary embolism with high sensitivity and specificity. In respect to lung perfusion and SUMMARY AND CONCLUSION 109 respiratory motion, lung MRI offers additional functional imaging capacities beyond the scope of X-ray and CT. With this, lung MRI offers not only solutions for tricky problems of daily routine but also is a good option for paediatrics and science or any situation where ionizing radiation or iodinated contrast agents are contraindicated, MRI can provide a valuable alternative to MDCT, for example in the detection of acute PE. For the same reason, MRI is a powerful tool for the surveillance of lung disease and monitoring of therapy. MRI has been developed to comprehensively image characteristic changes of the diseased lung, their functional precursors and the consequences at the level of perfusion, ventilation, and respiratory mechanism. So, lung MRI can be still challenging, being the most comprehensive but also most expensive and least robust of the three modalities. New users are advised to make themselves familiar with the particular advantages and limitations of the technique and its diagnostic scope to appreciate its potential benefits. Given this, lung MRI will be increasingly used and even further improved by additional recent and future developments, in particular in the fields of motion compensation and functional imaging .