arXiv:2602.07162physics.med-phcs.LG2026-02被引 1

通过滑块错位技术,实现3D高分辨率扩散MRI无伪影成像。

High-fidelity 3D multi-slab diffusion MRI using Slab-shifting for Harmonized 3D Acquisition and Reconstruction with Profile Encoding Networks (SHARPEN)

  • 利用滑块错位编码,实现无额外扫描时间的边界伪影抑制。
  • 在0.7毫米各向同性分辨率下,准确重建并消除层间伪影。
  • 无需高质量训练数据,适合临床场景与个体化建模。

三维多层成像因其兼容短重复时间(1-2秒),可提供最优信噪比效率,是实现高分辨率活体扩散MRI的有前景方法。然而,非理想选层射频激发导致的层边界伪影仍是主要挑战:非矩形层轮廓降低边界信号强度,层间重叠引发交叉干扰,重复激发缩短局部重复时间并限制T1恢复。为在不增加扫描时间的前提下缓解边界伪影,本文提出基于层轮廓编码的滑块错位技术(SHARPEN)。针对不同扩散方向,沿切片方向对不同体积施加视场偏移,实现互补层轮廓编码。采用轻量级自监督神经网络估计层轮廓,利用多偏移采集的一致性及层轮廓与扩散图像的物理特性进行建模,并据此重建修正图像。在模拟数据和前瞻性采集的高分辨率活体数据上验证表明,SHARPEN能精确估计层轮廓,鲁棒地消除边界伪影,即使存在体积间运动亦然。该方法无需高质量参考训练数据,支持个体化训练。其高效GPU实现相比NPEN更快更准,获得接近二维参考采集的逐层定量轮廓。本方法可在3T临床扫描仪上实现0.7毫米各向同性分辨率的高质量扩散MRI,凸显其推动亚毫米级扩散MRI用于神经科学研究的潜力。

原文摘要 · Abstract (English)

Three-dimensional (3D) multi-slab imaging is a promising approach for high-resolution in vivo diffusion MRI (dMRI) due to its compatibility with short TR (1-2 s), providing optimal signal-to-noise ratio (SNR) efficiency. A major challenge, however, is slab boundary artifacts arising from non-ideal slab-selective RF excitation. Non-rectangular slab profiles reduce signal intensity at slab boundaries, while profile overlap across adjacent slabs introduces inter-slab crosstalk, where repeated excitation shortens the local TR and limits T1 recovery. To mitigate slab boundary artifacts without increasing scan time, we build on slab profile encoding and propose Slab-shifting for Harmonized 3D Acquisition and Reconstruction with Profile Encoding Networks (SHARPEN). For different diffusion directions, SHARPEN applies inter-volume field-of-view shifts along the slice direction to provide complementary slab profile encoding without prolonging acquisition. Slab profiles are estimated using a lightweight self-supervised neural network that exploits consistency across shifted acquisitions and known physical properties of slab profiles and diffusion images, and corrected images are reconstructed accordingly. SHARPEN was validated using simulated and prospectively acquired high-resolution in vivo data and demonstrates accurate slab profile estimation and robust boundary artifact correction, even in the presence of inter-volume motion. SHARPEN does not require high-quality reference training data and supports subject-specific training. Its efficient GPU-based implementation delivers faster and more accurate correction than NPEN, yielding slice-wise quantitative profiles that closely match those from reference 2D acquisitions. SHARPEN enables high-quality dMRI at 0.7 mm isotropic resolution on a 3T clinical scanner, highlighting its potential to advance submillimeter dMRI for neuroscience research.

扩散MRI3D成像伪影校正深度学习

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