To assess the usefulness of non-contrast-enhanced MR angiography using cardiac and navigator-gated magnetization-prepared three-dimensional (3D) steady-state free precession (SSFP) imaging for the diagnosis of diseases of the thoracic aorta. Twenty-two patients with diseases of the thoracic aorta were examined using a 1.5 Tesla unit. Non-contrast-enhanced MR angiography was done using parasagittal 3D SSFP combined with cardiac-gating and k-space weighted navigator-gating techniques, using T2-prepared and fat-suppression pulses. Imaging quality and the diagnostic capability of this technique were compared with the imaging quality of 2D SSFP or contrast-enhanced 3D MR angiography and with final diagnoses. Non-contrast-enhanced 3D MR angiography provided signal-to-noise and contrast-to-noise ratios of the thoracic aorta comparable to non-contrast-enhanced 2D or contrast-enhanced 3D MR angiography (P > 0.17). This imaging technique gave accurate diagnoses in 19 of the 22 patients. Non-contrast-enhanced MR angiography using cardiac and navigator-gated magnetization-prepared 3D SSFP technique was useful for the diagnosis of diseases of the thoracic aorta.
