Multislice, dual-imaging sequence for increasing the dynamic range of the contrast-enhanced blood signal and CNR of myocardial enhancement at 3T

Purpose: To develop a multislice, first-pass perfusion imaging sequence for increasing the effective dynamic range of the contrast-enhanced blood signal and the contrast-to-noise ratio (CNR) of myocardial wall enhancement. Materials and Methods: A hybrid echo-planar imaging (EPI) pulse sequence was modified to acquire data for both the arterial input function (AIF) and the myocardium, using two different saturation-recovery time delays (TDs) and spatial resolutions, after a single saturation pulse. Five healthy subjects were scanned at 3T in three short-axis levels of the heart per heartbeat during passage of a high-dose bolus of contrast agent. The T₁-weighted signal-time curve of the blood was converted to AIF using empirical conversion tables derived from phantom experiments. Results: In all subjects the calculated AIF was consistently less distorted and higher for the short-TD protocol than for the long-TD protocol (peak concentration: 5.0 ± 1.0 mM vs. 3.0 ± 0.6 mM; P < 0.01). A combination of EPI, long TD, high-dose bolus of contrast agent, and 3T imaging yielded relatively strong peak enhancement in the myocardium (CNR = 11.9 ± 3.3). Conclusion: Our dual-imaging approach at 3T seems promising for acquiring both a relatively accurate AIF and a high CNR of myocardial wall enhancement in multiple slices per heartbeat.