Department of Radiology, Weill Cornell Medical College, New York, New York, USA.
Department of Biomedical Engineering, Cornell University, Ithaca, New York, USA.
Magn Reson Med. 2018 May;79(5):2795-2803. doi: 10.1002/mrm.26946. Epub 2017 Oct 11.
To develop a quantitative susceptibility mapping (QSM) method with a consistent zero reference using minimal variation in cerebrospinal fluid (CSF) susceptibility.
The ventricular CSF was automatically segmented on the R2* map. An L -regularization was used to enforce CSF susceptibility homogeneity within the segmented region, with the averaged CSF susceptibility as the zero reference. This regularization for CSF homogeneity was added to the model used in a prior QSM method (morphology enabled dipole inversion [MEDI]). Therefore, the proposed method was referred to as MEDI+0 and compared with MEDI in a numerical simulation, in multiple sclerosis (MS) lesions, and in a reproducibility study in healthy subjects.
In both the numerical simulations and in vivo experiments, MEDI+0 not only decreased the susceptibility variation within the ventricular CSF, but also suppressed the artifact near the lateral ventricles. In the simulation, MEDI+0 also provided more accurate quantification compared to MEDI in the globus pallidus, substantia nigra, corpus callosum, and internal capsule. MEDI+0 measurements of MS lesion susceptibility were in good agreement with those obtained by MEDI. Finally, both MEDI+0 and MEDI showed good and similar intrasubject reproducibility.
QSM with a minimal variation in ventricular CSF is viable to provide a consistent zero reference while improving image quality. Magn Reson Med 79:2795-2803, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
开发一种使用最小脑脊液（CSF）磁化率变化具有一致零参考的定量磁化率映射（QSM）方法。
在 R2* 图上自动分割脑室 CSF。使用 L-正则化来强制分割区域内 CSF 磁化率均匀，平均 CSF 磁化率作为零参考。这种 CSF 均匀性的正则化被添加到先前 QSM 方法（形态学使能偶极子反转[MEDI]）的模型中。因此，该方法被称为 MEDI+0，并在数值模拟、多发性硬化症（MS）病变以及健康受试者的可重复性研究中与 MEDI 进行了比较。
在数值模拟和体内实验中，MEDI+0 不仅降低了脑室 CSF 内的磁化率变化，而且还抑制了侧脑室附近的伪影。在模拟中，与 MEDI 相比，MEDI+0 还提供了更准确的苍白球、黑质、胼胝体和内囊的定量。MS 病变磁化率的 MEDI+0 测量结果与 MEDI 获得的结果吻合良好。最后，MEDI+0 和 MEDI 均表现出良好且相似的受试者内可重复性。
最小 CSF 变化的 QSM 可以提供一致的零参考，同时改善图像质量。磁共振医学 79:2795-2803, 2018。©2017 国际磁共振学会。
