Department of Biomedical Engineering & Physics, Amsterdam UMC, Amsterdam, The Netherlands.
MR Clinical Science, Philips Canada, Markham, Ontario, Canada.
NMR Biomed. 2021 Sep;34(9):e4567. doi: 10.1002/nbm.4567. Epub 2021 Jun 2.
The purpose of this study was to evaluate the use of a double delay alternating with nutation for tailored excitation (D-DANTE)-prepared sequence for banding-free isotropic high-resolution intracranial vessel wall imaging (IC-VWI) and to compare its performance with regular DANTE in terms of signal-to-noise ratio (SNR) as well as cerebrospinal fluid (CSF) and blood suppression efficiency. To this end, a D-DANTE-prepared 3D turbo spin echo sequence was implemented by interleaving two separate DANTE pulse trains with different RF phase-cycling schemes, but keeping all other DANTE parameters unchanged, including the total number of pulses and total preparation time. This achieved a reduction of the banding distance compared with regular DANTE enabling banding-free imaging up to higher resolutions. Bloch simulations assuming static vessel wall and flowing CSF spins were performed to compare DANTE and D-DANTE in terms of SNR and vessel wall/CSF contrast. Similar image quality measures were assessed from measurements on 13 healthy middle-aged volunteers. Both simulation and in vivo results showed that D-DANTE had only slightly lower vessel wall/CSF and vessel wall/blood contrast-to-noise ratio values compared with regular DANTE, which originated from a 10%-15% reduction in vessel wall SNR but not from reduced CSF or blood suppression efficiency. As anticipated, IC-VWI acquisitions showed that D-DANTE can successfully remove banding artifacts compared with regular DANTE with equal scan time or DANTE preparation length. Moreover, application was demonstrated in a patient with an intracranial aneurysm, indicating improved robustness to slow flow artifacts compared with clinically available 3D turbo spin echo scans. In conclusion, D-DANTE provides banding artifact-free IC-VWI up to higher isotropic resolutions compared with regular DANTE. This allows for a more flexible choice of DANTE preparation parameters in high-resolution IC-VWI protocols.
本研究旨在评估双延迟交替反转恢复激发（D-DANTE）准备序列在无带通自由各向同性高分辨率颅内血管壁成像（IC-VWI）中的应用，并比较其与常规 DANTE 在信噪比（SNR）以及脑脊液（CSF）和血液抑制效率方面的性能。为此，通过在两个具有不同 RF 相循环方案的单独 DANTE 脉冲串之间进行交错，同时保持所有其他 DANTE 参数不变，包括脉冲总数和总准备时间，实现了 D-DANTE 准备的 3D 涡轮自旋回波序列。这与常规 DANTE 相比，减少了带通距离，从而能够实现更高分辨率的无带通成像。模拟假设静态血管壁和流动 CSF 自旋的 Bloch 模拟用于比较 DANTE 和 D-DANTE 在 SNR 和血管壁/CSF 对比度方面的性能。在 13 名健康中年志愿者的测量中评估了相似的图像质量指标。模拟和体内结果均表明，D-DANTE 的血管壁/CSF 和血管壁/血液对比度噪声比与常规 DANTE 相比仅略有降低，这源于血管壁 SNR 降低 10%-15%，而不是 CSF 或血液抑制效率降低所致。正如预期的那样，IC-VWI 采集表明，与常规 DANTE 相比，D-DANTE 可以成功去除带通伪影，而扫描时间或 DANTE 准备长度相等。此外，在颅内动脉瘤患者中进行了应用，表明与临床可用的 3D 涡轮自旋回波扫描相比，对慢血流伪影的稳健性有所提高。总之，与常规 DANTE 相比，D-DANTE 可提供无带通伪影的 IC-VWI，达到更高的各向同性分辨率。这使得在高分辨率 IC-VWI 协议中可以更灵活地选择 DANTE 准备参数。
