Intraindividual assessment of the thoracic aorta using contrast and non-contrast-enhanced MR angiography

To avoid intravenous contrast media application, new MRA sequences using inherent blood contrast are available. The clinical use of these non-contrast-enhanced MRA (non-CE-MRA) sequences is still limited for the aorta. Thus, the goal was to compare a standard CE-MRA with a non-CE-MRA for the thoracic aorta.

Ethics committee approval and informed consent were obtained. CE-MRA and non-CE-MRA (1.5 T) were performed in the same 50 healthy volunteers (mean age: 48). CE-MRA: GRE-Turbo-Flash-3D (1.2 x 1.2 x 1.6 mm (3)), 0.15 mmol Gd/kg, TA 22 +/- 2 sec. Non-CE-MRA: Respiratory-and cardiac-gated, T 2-prepared 3D-trueFISP (1.2 x 1.2 x 1.3 mm (3)), TA 14 +/- 5 min. Assessment included (3 readers, consensus): image quality (sharpness of vessel wall, signal homogeneity, artifacts) at the ascending aorta, arch, descending aorta and supra-aortic vessels.

The image quality in the ascending aorta was rated 'excellent' in 78 %, 'moderate' in 22 %, 'poor' in 0 % for non-CE-MRA versus 22 %, 50 %, and 28 % for CE-MRA (Cohen's kappa = 29 %, McNemar p < 0.001). In a comparison of non-CE-MRA versus CE-MRA, the aortic arch and descending aorta showed no significant difference (kappa = 58 %/p = 0.250 and kappa = 100 %/p = 1.000, respectively). Supra-aortic vessels were rated 'excellent' 45 %/ 49 %, 'moderate' 30 %/ 49 % and 'poor' 13 %/ 2 %, 12 % of supra-aortic vessels were visualized < 1 cm at non-CE-MRA.

Diagnostic image quality of the thoracic aorta can be achieved without application of intravenous contrast media. Images of the aortic root using ECG-gated non-CE-MRA are superior to standard CE-MRA. This technique might be applicable in NSF patients.