1Keck School of Medicine of USC, Los Angeles, California.
2Fetal and Neonatal Institute, Division of Neonatology, Department of Pediatrics, Children's Hospital Los Angeles, Los Angeles, California.
J Neurosurg. 2022 Jun 10;138(2):367-373. doi: 10.3171/2022.5.JNS22767. Print 2023 Feb 1.
Advancements in MRI technology have provided improved ways to acquire imaging data and to more seamlessly incorporate MRI into modern pediatric surgical practice. One such situation is image-guided navigation for pediatric neurosurgical procedures, including intracranial catheter placement. Image-guided surgery (IGS) requires acquisition of CT or MR images, but the former carries the risk of ionizing radiation and the latter is associated with long scan times and often requires pediatric patients to be sedated. The objective of this project was to circumvent the use of CT and standard-sequence MRI in ventricular neuronavigation by investigating the use of fast MR sequences on the basis of 3 criteria: scan duration comparable to that of CT acquisition, visualization of ventricular morphology, and image registration with surface renderings comparable to standard of care. The aim of this work was to report image development, implementation, and results of registration accuracy testing in healthy subjects.
The authors formulated 11 candidate MR sequences on the basis of the standard IGS protocol, and various scan parameters were modified, such as k-space readout direction, partial k-space acquisition, sparse sampling of k-space (i.e., compressed sensing), in-plane spatial resolution, and slice thickness. To evaluate registration accuracy, the authors calculated target registration error (TRE). A candidate sequence was selected for further evaluation in 10 healthy subjects.
The authors identified a candidate imaging protocol, termed presurgical imaging with compressed sensing for time optimization (PICO). Acquisition of the PICO protocol takes 25 seconds. The authors demonstrated noninferior TRE for PICO (3.00 ± 0.19 mm) in comparison with the default MRI neuronavigation protocol (3.35 ± 0.20 mm, p = 0.20).
The developed and tested sequence of this work allowed accurate intraoperative image registration and provided sufficient parenchymal contrast for visualization of ventricular anatomy. Further investigations will evaluate use of the PICO protocol as a substitute for CT and conventional MRI protocols in ventricular neuronavigation.
磁共振成像（MRI）技术的进步为获取成像数据提供了更好的方法，并使 MRI 更无缝地融入现代儿科手术实践。一种这样的情况是用于儿科神经外科手术的图像引导导航，包括颅内导管放置。图像引导手术（IGS）需要获取 CT 或 MRI 图像，但前者有电离辐射的风险，后者则与较长的扫描时间有关，通常需要对儿科患者进行镇静。本项目的目的是通过研究基于以下 3 个标准的快速 MRI 序列的使用来避免在脑室神经导航中使用 CT 和标准序列 MRI：扫描持续时间与 CT 采集相当、显示脑室形态以及与标准护理相比的图像配准表面渲染。本工作的目的是报告图像开发、实施和在健康受试者中进行注册准确性测试的结果。
作者根据标准 IGS 方案制定了 11 种候选 MRI 序列，并修改了各种扫描参数，例如 K 空间读出方向、部分 K 空间采集、K 空间稀疏采样（即压缩感知）、平面空间分辨率和切片厚度。为了评估配准准确性，作者计算了目标配准误差（TRE）。作者选择了一种候选序列用于进一步评估 10 名健康受试者。
作者确定了一种候选成像方案，称为用于时间优化的压缩感知术前成像（PICO）。PICO 方案的采集时间为 25 秒。作者证明了 PICO（3.00 ± 0.19 毫米）与默认 MRI 神经导航方案（3.35 ± 0.20 毫米，p = 0.20）相比具有非劣效性 TRE。
这项工作开发和测试的序列允许术中进行精确的图像配准，并为可视化脑室解剖结构提供了足够的实质对比度。进一步的研究将评估将 PICO 方案用作脑室神经导航中 CT 和常规 MRI 方案的替代方案。
