Magnetic resonance tomography in the diagnosis of lung metastases in the mediastinum and thorax

The results of MRI in 81 patients with morphologically verified lung cancer, mainly Stages IIIA and IIIB, were analyzed. They were compared with CT data in 37 cases and surgical findings in 28. MRI was performed by using Magnaview 0.04 T and Vectra 0.5 T apparatus in the T1- and T2-weighted SE and PC sequences as well in the fat-suppression mode. Thoracic metastases were evaluated from the direct signs tumor spread into the adjacent tissue and vessels. The criteria for the involvement of lymph nodes were their over 1-cm enlargement and characteristic changes in the intensity of signals from them. CT was found to yield less information on pleural, pericardial, and vascular invasion (66-75% sensitivity). MRI detected this type of cancer spread (88-94% sensitivity). Both techniques have nearly equal sensitivities in revealing intrathoracic lymphadenopathy. The interpretation of MRI data did not depend on the voltage of a magnetic field. It is recommended that MRI should be made after CT when there is a need for assessing large vessels or for making clear the data that remain open to question following CT.