Twenty-four patients whose mediastinal (12 patients) and lung (12 patients) neoplasms were eventually verified were evaluated with cine MRI in addition to conventional methods (plain radiography, CT, MRI, and endoscopy). Using a 1.0 T system and gradient echo (FLASH repetition time 250-350 ms, echo time 12, flip angle 25-60 degrees) multislice pulse sequence, cine MRI was performed combined with cardiac gating. At the level of the pulmonary artery, the CT, spin echo (SE) MRI, and cine MRI findings were evaluated blindly by three groups of radiologists to determine whether the pulmonary artery was infiltrated or dynamically stenotic. Cine MRI allowed an overall diagnostic accuracy of 100% in comparison with SE MRI (91.6%) and CT (91.6%).