[MR imaging in the assessment of lung cancer patients: primary lung cancer staging, evaluation of therapeutic effect and diagnosis of recurrent tumor].

Magnetic resonance imaging and computed tomography were compared in a prospective study of 137 lung cancer patients proved by surgery or autopsy for determining the staging, evaluation of therapeutic effect and diagnosis of recurrent tumor. 1. Lung cancer staging In peripheral lung cancer, T1 and T2 relaxation times of the tumors before operation have some correlation with those of operated specimens. These relaxation times, however, are of limited nodule characterization. Hilar mass and adjacent pulmonary consolidation (obstructive pneumonia or collapse) can be distinguished on T2-weighted image (77%) and Gd-DTPA enhanced image (80%). Therefore these images help in distinguishing tumor from peripheral lung disease. In the diagnosis of tumor invasion to the heart and great vessels, MRI is superior to CT because MRI can be helpful in distinguishing true mass from heart and great vessels. As for the chest wall, MRI is more useful than CT in detecting tumor invasion especially to the thoracic inlet and superior regions. In the diagnosis of mediastinal and hilar lymphadenopathy, MRI is equivalent or slightly inferior to CT, but MRI can easily demonstrate the lymphadenopathy at subcarinal region on coronal image. 2. Evaluation of therapeutic effect in lung cancer patients treated by radiation and chemotherapy MRI patterns of therapeutic effect was divided into 3 types. It is suggested that there is some correlation between these patterns and histologic types. MRI can easily demonstrate necrotic area on T2-weighted and Gd-DTPA enhanced images. 3. Diagnosis of recurrent tumor in treated lung cancer Concerning detecting recurrent tumor after surgery or irradiation, and delineating tumor from radiation pneumonitis, T2-weighted and Gd-DTPA enhanced images are of clinical value.