Kim Taeho
Sean Pollock, Danny Lee, Paul Keall, University of Sydney, Sydney, Australia.
Med Phys. 2012 Jun;39(6Part3):3616-3617. doi: 10.1118/1.4734682.
Previous studies have investigated the effect of AV biofeedback on the external respiratory signal reproducibility. This is the first study investigating the effect of AV biofeedback to improve the motion reproducibility of the internal anatomy. The aim of the project is to test the hypothesis that AV biofeedback improves the diaphragm motion reproducibility.
An AV biofeedback system has been employed with MRI acquisitions. The AV biofeedback system utilized (1) the external marker position on the abdomen using an RPM system (Real-time Position Management, Varian) to audio-visually guide a human subject for regular breathing and (2) a fast Gradient-Recalled-Echo (fGRE) MR pulse sequence of 3 Tesla GE MRI (GE Healthcare) to monitor the diaphragm motion (200ms). The improvement in the diaphragm motion reproducibility using the AV biofeedback system combined with MRI has been assessed in 26 studies with 13 healthy human subjects. Each subject underwent two studies for assessment of the diaphragm motion reproducibility both with AV biofeedback and without (free breathing). The second study features a reversed order of breathing conditions. The total MRI acquisitions across the 26 studies are 202 measurements including sagittal and coronal planes.
Average RMSE (root mean square error) of diaphragm displacement obtained from MRI analysis has been reduced from 2.7mm of free breathing to 1.6mm of AV biofeedback breathing (p-value < 0.05). Additionally, the average RMSE of diaphragm motion period was reduced from 1.84s with free breathing to 0.34s with AV biofeedback breathing (p- value < 0.05). 22% of average displacement error was reduced using AV biofeedback in the first study, and 47% reduction in the second study.
The study demonstrated the improvement in the diaphragm motion reproducibility using AV biofeedback. This system can provide clinically applicable motion management of the internal anatomy in MRI and for Image Guided Radiotherapy (IGRT).
以往研究探讨了听觉视觉生物反馈对外部呼吸信号再现性的影响。本研究首次探讨听觉视觉生物反馈对改善内部解剖结构运动再现性的作用。该项目的目的是检验听觉视觉生物反馈可提高膈肌运动再现性这一假设。
将听觉视觉生物反馈系统与磁共振成像（MRI）采集相结合。该听觉视觉生物反馈系统利用：（1）使用RPM系统（实时位置管理，瓦里安公司）获取腹部外部标记物位置，以视听方式引导受试者进行规律呼吸；（2）采用3特斯拉通用电气MRI（通用电气医疗集团）的快速梯度回波（fGRE）磁共振脉冲序列监测膈肌运动（200毫秒）。在对13名健康受试者进行的26项研究中，评估了结合MRI的听觉视觉生物反馈系统对膈肌运动再现性的改善情况。每位受试者均接受两项研究，分别在有听觉视觉生物反馈和无听觉视觉生物反馈（自由呼吸）的情况下评估膈肌运动再现性。第二项研究采用了相反的呼吸条件顺序。26项研究中的MRI采集总数为202次测量，包括矢状面和冠状面。
通过MRI分析获得的膈肌位移平均均方根误差（RMSE）已从自由呼吸时的2.7毫米降至听觉视觉生物反馈呼吸时的1.6毫米（p值<0.05）。此外，膈肌运动周期的平均RMSE已从自由呼吸时的1.84秒降至听觉视觉生物反馈呼吸时的0.34秒（p值<0.05）。在第一项研究中，使用听觉视觉生物反馈使平均位移误差降低了22%，在第二项研究中降低了47%。
该研究证明了使用听觉视觉生物反馈可改善膈肌运动再现性。该系统可为MRI和图像引导放射治疗（IGRT）中的内部解剖结构提供临床适用的运动管理。
