NonCartesian MR image reconstruction with integrated gradient nonlinearity correction
NonCartesian MR image reconstruction with integrated gradient nonlinearity correction
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DOI：
10.1118/1.4936098
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发表时间：
2015-12-01
期刊：
影响因子：
3.8
通讯作者：
Bernstein, Matt A.
中科院分区：
文献类型：
--
作者：
Tao, Shengzhen;Trzasko, Joshua D.;Bernstein, Matt A.
目的：推导一种用于非笛卡儿磁共振成像(MRI)的非迭代网格型重建框架，与重建后应用的标准的基于图像域的GNL校正不同，该框架前瞻性地解释了在MR图像重建过程中梯度非线性(GNL)引起的图像几何失真；为了证明该框架能够减少传统GNL校正带来的图像模糊，同时仍然能够有效地校正GNL引起的几何失真并与非共振校正兼容。方法：在引入显式地考虑GNL和非共振影响的非笛卡儿MRI信号模型的基础上，推导了基于III型非均匀快速傅立叶变换(NUFFT)的集成GNL校正的非迭代网格型重建框架。然后提出了一种新的III型NUFFT实现，作为所提出框架的数值高效解决方案。然后讨论了在所提出的框架中加入同时B-0非共振校正的问题。使用不同的二维和三维非笛卡尔采集的体模和活体数据，包括二维阿基米德螺线，三维壳体的径向和螺旋一体化，以及三维径向采样，比较了所提出的校正方法和标准的GNL校正方法的结果。结果：各种体模和活体数据表明，所提出的校正方法和标准的GNL校正方法都能够校正由GNL和非共振引起的粗尺度几何失真和模糊。然而，标准GNL校正方法也会对校正后的图像引入模糊效果，导致模型图像中分辨率插入的模糊以及血管造影术实例中小血管清晰度的丧失。结论：本文提出的GNL综合非笛卡尔重建方法可以有效地降低标准图像域GNL校正过程中的分辨率损失，同时仍能有效地纠正GNL和非共振引起的大尺度几何失真和模糊。(C)2015年美国医学物理学家协会。
Purpose: To derive a noniterative gridding-type reconstruction framework for nonCartesian magnetic resonance imaging (MRI) that prospectively accounts for gradient nonlinearity (GNL)-induced image geometrical distortion during MR image reconstruction, as opposed to the standard, image-domain based GNL correction that is applied after reconstruction; to demonstrate that such framework is able to reduce the image blurring introduced by the conventional GNL correction, while still offering effective correction of GNL-induced geometrical distortion and compatibility with off-resonance correction.Methods: After introducing the nonCartesian MRI signal model that explicitly accounts for the effects of GNL and off-resonance, a noniterative gridding-type reconstruction framework with integrated GNL correction based on the type-III nonuniform fast Fourier transform (NUFFT) is derived. A novel type-III NUFFT implementation is then proposed as a numerically efficient solution to the proposed framework. The incorporation of simultaneous B-0 off-resonance correction to the proposed framework is then discussed. Several phantom and in vivo data acquired via various 2D and 3D nonCartesian acquisitions, including 2D Archimedean spiral, 3D shells with integrated radial and spiral, and 3D radial sampling, are used to compare the results of the proposed and the standard GNL correction methods.Results: Various phantom and in vivo data demonstrate that both the proposed and the standard GNL correction methods are able to correct the coarse-scale geometric distortion and blurring induced by GNL and off-resonance. However, the standard GNL correction method also introduces blurring effects to corrected images, causing blurring of resolution inserts in the phantom images and loss of small vessel clarity in the angiography examples. On the other hand, the results after the proposed GNL correction show better depiction of resolution inserts and higher clarity of small vessel.Conclusions: The proposed GNL-integrated nonCartesian reconstruction method can mitigate the resolution loss that occurs during standard image-domain GNL correction, while still providing effective correction of coarse-scale geometric distortion and blurring induced by GNL and off-resonance. (C) 2015 American Association of Physicists in Medicine.