[Invasion of esophageal cancer to neighboring structures: diagnosis by CT, conventional MR imaging and cine-MR imaging].

Seventy-four esophageal cancer patients were examined by magnetic resonance (MR) imaging and CT to evaluate invasion to the aorta and tracheobronchial tree. Aortic invasion was evaluated by axial section on MR and CT. A contact angle of less than 60 degrees indicated that the cancer had not invaded to the wall of the aorta (A2 or under). When the contact angle was 60 degrees or greater and irregularity of the contact plane was noted, aortic invasion was considered positive (A3). With this criterion, the accuracy rates of MR and CT were 84% and 78%, respectively. For evaluation of the invasion of esophageal cancer to the aorta, 39 cases were examined by cine-MR imaging. Gradient echo pulse sequence was used. When a low intensity stripe was recognized between the tumor and the wall of the aorta, this was interpreted as a negative finding of direct tumor invasion. Using this criterion, 36 of 39 cases (92%) of esophageal cancer invading to the aortic wall were correctly diagnosed. Tracheobronchial invasion was evaluated according to the deformities of the trachea and bronchi by contiguous cancers. The accuracy rates of MR and CT with this criterion were 96% and 95%, respectively. MR imaging is a useful and reliable means for the evaluation of esophageal cancer invading to the neighboring structures.