Physiology-Based MR Imaging Assessment of CSF Flow at the Foramen Magnum with a Valsalva Maneuver
Physiology-Based MR Imaging Assessment of CSF Flow at the Foramen Magnum with a Valsalva Maneuver
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DOI：
10.3174/ajnr.a3509
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发表时间：
2013-09-01
影响因子：
3.5
通讯作者：
Patz, S.
中科院分区：
文献类型：
--
作者：
Bhadelia, R. A.;Madan, N.;Patz, S.
背景与目的：由于短暂的生理动作，磁共振成像目前未用于评估脑脊液（CSF）流动变化。本研究的目的是评估磁共振成像在健康受试者中评估瓦尔萨尔瓦动作（Valsalva maneuver）引起的脑脊液流动反应的能力。
材料与方法：采用采集时间为15秒的心脏门控快速电影相位对比（cine - PC）序列，评估8名健康受试者在静息时、进行控制的瓦尔萨尔瓦动作期间以及动作结束后即刻枕骨大孔处的脑脊液流动。测定心动周期内脑脊液平均位移体积（V - CSF）和脑脊液流动波形幅度（A(pp)）。采用一种正在研发的实时笔形束成像方法（时间分辨率为56毫秒）对2名受试者扫描90秒，在此期间持续记录静息、瓦尔萨尔瓦动作期间和动作结束后的脑脊液流动、呼吸以及心率。将结果与文献中的有创颅脊压差测量结果进行定性比较。
结果：两种方法均显示：1）在瓦尔萨尔瓦动作期间，V - CSF和A(pp)较基线值降低；2）与静息时和瓦尔萨尔瓦动作期间所测值相比，瓦尔萨尔瓦动作结束后V - CSF和A(pp)立即升高。快速电影相位对比产生的单个脑脊液流动波形是多个心动周期的平均值，而笔形束成像描绘了每次心跳的波形，并能够捕捉脑脊液流动的许多动态特征，包括与瓦尔萨尔瓦动作同步的瞬态变化。
结论：快速电影相位对比和笔形束成像均在健康受试者中显示出瓦尔萨尔瓦动作引起的脑脊液流动的预期变化。笔形束成像的实时能力可能对于检测诸如I型小脑扁桃体下疝畸形等病理状况患者中与瓦尔萨尔瓦动作相关的脑脊液流动瞬时阻塞是必要的。
BACKGROUND AND PURPOSE: MR imaging is currently not used to evaluate CSF flow changes due to short-lasting physiological maneuvers. The purpose of this study was to evaluate the ability of MR imaging to assess the CSF flow response to a Valsalva maneuver in healthy participants.MATERIALS AND METHODS: A cardiac-gated fast cine-PC sequence with 15-second acquisition time was used to assess CSF flow in 8 healthy participants at the foramen magnum at rest, during, and immediately after a controlled Valsalva maneuver. CSF mean displacement volume V-CSF during the cardiac cycle and CSF flow waveform A(pp) were determined. A work-in-progress real-time pencil-beam imaging method with temporal resolution 56 ms was used to scan 2 participants for 90 seconds during which resting, Valsalva, and post-Valsalva CSF flow, respiration, and HR were continuously recorded. Results were qualitatively compared with invasive craniospinal differential pressure measurements from the literature.RESULTS: Both methods showed 1) a decrease from baseline in V-CSF and A(pp) during Valsalva and 2) an increase in V-CSF and A(pp) immediately after Valsalva compared with values measured both at rest and during Valsalva. Whereas fast cine-PC produced a single CSF flow waveform that is an average over many cardiac cycles, pencil-beam imaging depicted waveforms for each heartbeat and was able to capture many dynamic features of CSF flow, including transients synchronized with the Valsalva maneuver.CONCLUSIONS: Both fast cine-PC and pencil-beam imaging demonstrated expected changes in CSF flow with Valsalva maneuver in healthy participants. The real-time capability of pencil-beam imaging may be necessary to detect Valsalva-related transient CSF flow obstruction in patients with pathologic conditions such as Chiari I malformation.