Magnetic resonance coronary angiography with Vasovist: in-vivo T1 estimation to improve image quality of navigator and breath-hold techniques.

The purpose of the study was to estimate T1 values of blood and myocardium after a single injection of Vasovist and to assess Vasovist for magnetic resonance coronary angiography (MRCA). For all exams 0.05 mmol/kg of Vasovist was injected. T1 values of blood and myocardium were estimated over 30 min after injection. Twelve volunteers were examined on a 1.5-T Siemens system using a SSFP sequence with incrementally increasing inversion times for T1-estimation and a breath-hold 3D IR-FLASH sequence for MRCA. Eleven examinations were performed on 1.5-T Philips system using the Look-Locker approach for T1 estimation and a whole-heart inversion-prepared, 3D SSFP sequence for MRCA. SNR, CNR and image quality were assessed. T1 values of blood (5 min: 230 ms vs. 30 min: 275 ms) and myocardium (5 min: 99 ms vs. 30 min: 130 ms) increased over time. Whereas the blood SNR (1 min: 23.6 vs. 30 min: 21.2) showed no significant differences, the blood-to-myocardium CNR (1 min: 18.1 vs. 30 min: 13.8) and the image quality (1 min: 2.9 vs. 30 min: 3.8) degraded over time. Due to long plasma half-time the T1-shortening effect of Vasovist remains effective over 30 min, which allows for multiple breath-hold or high-resolution MRCA.