[Magnetic resonance tomography in the assessment of questionable aneurysm of the thoracic aorta with or without dissection of the intima].

To assess the value of MRI in the diagnosis of aneurysm of the thoracic aorta with suspected or known dissection 23 patients were imaged with cardiac gating. Seven patients (group 1) had known dissection of the thoracic aorta; in 16 patients (group 2) an aneurysm was suspected by chest x-ray or 2D-echocardiography. Reference methods were: x-ray, 2D-echocardiography, angiography, and computered tomography. In the first group MRI clearly identified the intimal flap, could differentiate between true and false lumen, slow flow, and thrombus, respectively. In the second group MRI could exclude a dissection of the ectatic part of the thoracic aorta in 11 patients and demonstrate paracardiac or mediastinal mass in five patients. MRI can serve as an important diagnostic tool in known or suspected aneurysm of the thoracic aorta.