Double inversion black-blood fast spin-echo imaging of the human heart: A comparison between 1.5T and 3.0T

Purpose: To evaluate the effectiveness of blood suppression and the quality of black-blood cardiac images acquired at 3.0 Tesla using a double-inversion recovery fast spinecho sequence by comparing data acquired at 3.0T to data acquired at 1.5T. Materials and Methods: Black-blood T2-weighted fast spinecho images of the heart were acquired from five normal volunteers at 1.5T and five normal volunteers at 3.0T. Regionof-interest signal intensity measurements were performed at several locations in the suppressed blood regions of the left and right ventricles and around the left ventricle walls to assess the effectiveness and uniformity of the blood suppression, the myocardial signal-to-noise ratio (SNR), and the signal uniformity at both field strengths, B1 field maps were produced in phantoms and in subjects at both field strengths. Results: Blood suppression performance is equivalent at 1.5T and 3.0T. The improvement in SNR at 3.0T compared with 1.5T is less than has been predicted in previous studies. The signal uniformity is significantly poorer at 3.0T than at 1.5T due to dielectric effects and shorter radio frequency wavelengths (P < 0.005). Conclusion: Spin-echo and spin-echo echo-train sequences that perform well at 1.5T will produce large signal variations in the chest cavity at 3.0T without modifications. B1 insensitive methods must be explored and implemented for spin-echo sequences to fully realize the advantages of using these sequences for high-field MRI.