Objectives: The objective of this study was to assess the evolution of T1 contrast (T1c) between cardiovascular tissues, contrast agents, and magnetic field strengths.
Materials and methods: This Health Insurance Portability and Accountability Act-compliant study was approved by the institutional review board, and written informed consent was obtained from all participants. Eight healthy volunteers were recruited to undergo 4 consecutive magnetic resonance (MR) scans with the same imaging parameters. Scans 1 and 2 were performed using a 3-T MR scanner, and scans 3 and 4 were performed using a 1.5-T MR scanner. Gadofosveset trisodium (0.03 mmol/kg) was injected for scans 1 and 3, and gadopentetate dimeglumine (Gd-DTPA) (0.1 mmol/kg) was used for scans 2 and 4. Modified Look-Locker inversion recovery T1 maps with a midventricular short-axis view were acquired before contrast and repeated every 5 minutes until 45 minutes after contrast agent administration. T1 contrast tissue (T1(myocardium) - T1(blood)), T1c agent (T1Gd-DTPA - T1(Gadofosveset)), and T1c field (T1(3T) - T1(1.5T)) were calculated and compared using t tests.
Results: The T1c tissue of the 3-T scanner was larger than that of the 1.5-T scanner for both contrast agents. In both the myocardium and the blood pool, the T1c agent of the 1.5-T scanner was larger than that of the 3-T scanner. Gadofosveset trisodium exhibited a larger T1c field and T1c tissue than did Gd-DTPA. The T1c tissue induced by Gd-DTPA diminished faster than that induced by gadofosveset trisodium at both 1.5 and 3 T.
Conclusions: Our study demonstrates the independent effects of timing, contrast agent type, and magnetic field strength on postcontrast T1c under general physiological conditions. The behaviors of T1c can be used to tailor quantitative MR imaging protocols for various clinical purposes.