Philips Research Europe, Roentgenstrasse 24-26, 22335 Hamburg, Germany.
Philips Research Europe, Roentgenstrasse 24-26, 22335 Hamburg, Germany.
Magn Reson Imaging. 2024 Jan;105:10-16. doi: 10.1016/j.mri.2023.10.007. Epub 2023 Oct 19.
Diffusion-weighted double-echo steady-state (dwDESS) MRI with bipolar diffusion gradients is a promising candidate to obtain diffusion weighted images (DWI) free of geometric distortions and with low motion sensitivity. However, a wider clinical application of dwDESS is currently hindered as no method is reported to explicitly calculate the effective b-value of the obtained DWI from the diffusion-gradients applied in the sequence. To this end, a previously described signal model was adapted for dwDESS with bipolar diffusion gradients, which allows to estimate an effective b-value, dubbed b'. Evaluation in phantom examinations was performed on a clinical 1.5 T MR system. Experimental results were compared with theoretical predictions, including the apparent diffusion coefficient (ADC) based on b-values from a standard EPI-DWI sequence and ADC' based on the effective b' from the dwDESS sequence. The adapted signal model was able to describe the experimental results, and the obtained values of ADC' were in line with conventional ADC measurements.
双极扩散梯度稳态（dwDESS）弥散加权磁共振成像（MRI）是一种很有前途的方法，可以获得无几何变形且对运动不敏感的弥散加权图像（DWI）。然而，由于目前没有报道从序列中应用的扩散梯度中明确计算获得的 DWI 的有效 b 值的方法，因此 dwDESS 的更广泛的临床应用受到阻碍。为此，我们对双极扩散梯度的 dwDESS 进行了信号模型的改编，该模型可以估计有效 b 值，称为 b'。在临床 1.5T MR 系统上进行了体模检查的评估。实验结果与理论预测进行了比较，包括基于标准 EPI-DWI 序列 b 值的表观弥散系数（ADC）和基于 dwDESS 序列有效 b'的 ADC'。改编后的信号模型能够描述实验结果，并且获得的 ADC'值与常规 ADC 测量值一致。
