Yazdanbakhsh Pedram, Couch Marcus J, Sprang Christian, Gilbert Kyle M, Feizollah Sajjad, Tardif Christine L, Rudko David A
McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, Montreal, Quebec, Canada.
Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada.
Magn Reson Med. 2025 Aug 5. doi: 10.1002/mrm.70011.
The purpose of this work was to design and build a size-adaptive pediatric RF head coil for 7 T neuroimaging. The coil can be safely applied for imaging children 4-9 years old.
The pediatric head coil incorporates eight, transmit dipole elements for operation in parallel transmit (pTx) mode. The receive architecture is comprised of a 32-channel conformal, size-adaptive receive array. Receive elements were arranged into five sections of a mechanically adjustable 3D printed head former, allowing adjustment of the receive array according to child head size. The transmit coil was carefully simulated to calculate specific absorption rate (SAR) and B efficiency. Coil performance was then evaluated with a pediatric head phantom at both the largest and smallest dimensions of the receive former. In vivo imaging was carried out in 3 pediatric subjects (aged 5, 6, and 9 years old) to acquire B field maps and anatomical MP2RAGE images.
A comparison of simulated and experimental B performance in the pediatric head phantom was used to validate SAR models and to demonstrate that the coil was safe for pediatric imaging. The SNR performance in the pediatric phantom was improved by adjusting the position of the receive array to the smallest possible position. The in vivo B efficiency agreed with expectations, and the coil provided precise anatomical images of the brain.
The proposed size-adaptive coil enables safe, high-quality imaging of children at 7 T, with a range of ages and head sizes. Accurate SAR modeling enabled imaging using both combined circularly polarized and dynamic pTx modes.
本研究旨在设计并构建一款适用于7T神经成像的尺寸自适应儿科射频头部线圈。该线圈可安全应用于4至9岁儿童的成像。
儿科头部线圈包含八个用于并行发射（pTx）模式操作的发射偶极子元件。接收架构由一个32通道共形、尺寸自适应接收阵列组成。接收元件被布置在一个机械可调的3D打印头模的五个部分中，允许根据儿童头部大小调整接收阵列。对发射线圈进行了仔细模拟，以计算比吸收率（SAR）和B效率。然后在接收头模的最大和最小尺寸下，使用儿科头部模型评估线圈性能。对3名儿科受试者（年龄分别为5岁、6岁和9岁）进行了体内成像，以获取B场图和解剖学MP2RAGE图像。
通过比较儿科头部模型中模拟和实验的B性能，验证了SAR模型，并证明该线圈对儿科成像安全。通过将接收阵列调整到尽可能小的位置，提高了儿科模型中的信噪比性能。体内B效率符合预期，该线圈提供了精确的脑部解剖图像。
所提出的尺寸自适应线圈能够在7T下对不同年龄和头部大小的儿童进行安全、高质量的成像。精确的SAR建模使得能够使用组合圆极化和动态pTx模式进行成像。
