Hallgren Richard C, Rowan Jacob J
J Am Osteopath Assoc. 2019 Mar 1;119(3):173-182. doi: 10.7556/jaoa.2019.028.
Disorders of the rectus capitis posterior minor (RCPm) muscles have been associated with chronic headache. Magnetic resonance (MR) imaging protocols currently used in clinical settings do not result in image sets that can be used to adequately visualize the integrity of occipitoatlantal structures or to definitively quantify time-dependent functional morphologic changes.
To develop an MR imaging protocol that provides the superior image quality needed to visualize occipitoatlantal soft tissue structures and quantify time-dependent pathologic changes.
Asymptomatic participants were recruited from the Michigan State University College of Osteopathic Medicine student body. Magnetic resonance imaging data were collected from each participant at enrollment and 2 weeks after enrollment using a 3T magnet. A conventional spin-echo pulse sequence was used to construct 24 axial, T1-weighted images with the following measurement parameters: repetition time, 467 milliseconds; echo time, 13.5 milliseconds; number of excitations, 4; slice thickness, 3.0 mm; and in-plane resolution, 0.625×0.625 mm. Image planes were aligned approximately perpendicular to the long axes of the RCPm muscles to facilitate the authors' ability to accurately draw regions of interest around the specific muscle boundaries. Cross-sectional area (CSA) of the right and left RCPm muscles was quantified for each participant at the 2 points in time. The null hypothesis was that there would be no significant difference between mean values of muscle CSA collected at enrollment and 2 weeks after enrollment for a given participant and a given side of his or her body.
Thirteen participants were enrolled. No significant difference was found between mean values of either right or left RCPm muscle CSA for any of the participants measured at enrollment and 2 weeks after enrollment (all P>.05).
The protocol achieves the superior image quality necessary to compare the functional form of occipitoatlantal structures at progressive points in time.
头后小直肌（RCPm）紊乱与慢性头痛有关。目前临床使用的磁共振（MR）成像方案所得到的图像集，无法充分显示枕寰结构的完整性，也无法明确量化随时间变化的功能形态学改变。
制定一种MR成像方案，以提供可视化枕寰软组织结构及量化随时间变化的病理改变所需的优质图像质量。
从密歇根州立大学整骨医学院学生群体中招募无症状参与者。使用3T磁体在入组时和入组后2周收集每位参与者的磁共振成像数据。采用传统自旋回波脉冲序列构建24幅轴向T1加权图像，测量参数如下：重复时间467毫秒；回波时间13.5毫秒；激励次数4次；层厚3.0毫米；平面分辨率0.625×0.625毫米。图像平面大致垂直于RCPm肌肉的长轴排列，以便作者能够准确地在特定肌肉边界周围绘制感兴趣区域。在两个时间点对每位参与者左右RCPm肌肉的横截面积（CSA）进行量化。零假设是，对于给定参与者及其身体的给定一侧，入组时和入组后2周收集的肌肉CSA平均值之间无显著差异。
共招募了13名参与者。在入组时和入组后2周测量的任何参与者的左右RCPm肌肉CSA平均值之间均未发现显著差异（所有P>0.05）。
该方案实现了在不同时间点比较枕寰结构功能形态所需的优质图像质量。
