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Original Article

Korean Journal of Medical Physics 2014; 25(2): 72-78

Published online June 30, 2014

Copyright © Korean Society of Medical Physics.

Quasi-breath-hold (QBH) Biofeedback in Gated 3D Thoracic MRI: Feasibility Study

게이트 흉부자기 공명 영상법과 함께 사용할 수 있는 의사호흡정지(QBH) 바이오 피드백

Taeho Kim*†‡, Robert Pooley§, Danny Lee, Paul Keall, Rena Lee, Siyong Kim*

김태호*†‡ㆍRobert Pooley§ㆍDanny LeeㆍPaul Keallㆍ이레나ㆍ김시용*

*Department of Radiation Oncology, University of Virginia, Virginia, USA, Department of Radiation Oncology, Mayo Clinic, Florida, USA, Department of Radiation Oncology, Ewha Womans University, Seoul, Korea, §Department of Radiology, Mayo Clinic, Florida, USA, Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney, Australia, Department of Radiation Oncology, Virginia Commonwealth University, Virginia, USA

*Department of Radiation Oncology, University of Virginia, Virginia, USA, Department of Radiation Oncology, Mayo Clinic, Florida, USA, 이화여자대학교 방사선종양학과, §Department of Radiology, Mayo Clinic, Florida, USA, Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney, Australia, Department of Radiation Oncology, Virginia Commonwealth University, Virginia, USA

Received: May 8, 2014; Revised: May 26, 2014; Accepted: June 2, 2014

Abstract

The aim of the study is to test a hypothesis that quasi-breath-hold (QBH) biofeedback improves the residual respiratory motion management in gated 3D thoracic MR imaging, reducing respiratory motion artifacts with insignificant acquisition time alteration. To test the hypothesis five healthy human subjects underwent two gated MR imaging studies based on a T2 weighted SPACE MR pulse sequence using a respiratory navigator of a 3T Siemens MRI: one under free breathing and the other under QBH biofeedback breathing. The QBH biofeedback system utilized the external marker position on the abdomen obtained with an RPM system (Real-time Position Management, Varian) to audio-visually guide a human subject for 2s breath-hold at 90% exhalation position in each respiratory cycle. The improvement in the upper liver breath-hold motion reproducibility within the gating window using the QBH biofeedback system has been assessed for a group of volunteers. We assessed the residual respiratory motion management within the gating window and respiratory motion artifacts in 3D thoracic MRI both with/without QBH biofeedback. In addition, the RMSE (root mean square error) of abdominal displacement has been investigated. The QBH biofeedback reduced the residual upper liver motion within the gating window during MR acquisitions (∼6 minutes) compared to that for free breathing, resulting in the reduction of respiratory motion artifacts in lung and liver of gated 3D thoracic MR images. The abdominal motion reduction in the gated window was consistent with the residual motion reduction of the diaphragm with QBH biofeedback. Consequently, average RMSE (root mean square error) of abdominal displacement obtained from the RPM has been also reduced from 2.0 mm of free breathing to 0.7 mm of QBH biofeedback breathing over the entire cycle (67% reduction, p-value=0.02) and from 1.7 mm of free breathing to 0.7 mm of QBH biofeedback breathing in the gated window (58% reduction, p-value=0.14). The average baseline drift obtained using a linear fit was reduced from 5.5 mm/min with free breathing to 0.6 mm/min (89% reduction, p-value=0.017) with QBH biofeedback. The study demonstrated that the QBH biofeedback improved the upper liver breath-hold motion reproducibility during the gated 3D thoracic MR imaging. This system can provide clinically applicable motion management of the internal anatomy for gated medical imaging as well as gated radiotherapy.

KeywordsGated 3D thoracic MRI, Quasi-breath-hold biofeedback, Respiratory motion management

Korean Society of Medical Physics

Vol.35 No.4
December 2024

pISSN 2508-4445
eISSN 2508-4453
Formerly ISSN 1226-5829

Frequency: Quarterly

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