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Title: Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI

Abstract

Purpose: In this work, the authors present a novel magnetic resonance imaging reconstruction method to improve the quality of MR images in the presence of respiratory motion for real-time thoracic image-guided radiotherapy. Methods: This new reconstruction method is called dynamic keyhole and utilizes a library of previously acquired, peripheral k-space datasets from the same (or similar) respiratory state in conjunction with central k-space datasets acquired in real-time. Internal or external respiratory signals are utilized to sort, match, and combine the two separate peripheral and central k-space datasets with respect to respiratory displacement, thereby reducing acquisition time and improving image quality without respiratory-related artifacts. In this study, the dynamic keyhole, conventional keyhole, and zero-filling methods were compared to full k-space acquisition (ground truth) for 60 coronal datasets acquired from 15 healthy human subjects. Results: For the same image-quality difference from the ground-truth image, the dynamic keyhole method reused 79% of the prior peripheral phase-encoding lines, while the conventional keyhole reused 73% and zero-filling 63% (p-value < 0.0001), corresponding to faster acquisition speed of dynamic keyhole for real-time imaging applications. Conclusions: This study demonstrates that the dynamic keyhole method is a promising technique for clinical applications such as image-guided radiotherapy requiring real-timemore » MR monitoring of the thoracic region. Based on the results from this study, the dynamic keyhole method could increase the temporal resolution by a factor of five compared with full k-space methods.« less

Authors:
; ; ; ;  [1]
  1. Radiation Physics Laboratory, Sydney Medical School, University of Sydney, Sydney 2006 (Australia)
Publication Date:
OSTI Identifier:
22412528
Resource Type:
Journal Article
Resource Relation:
Journal Name: Medical Physics; Journal Volume: 41; Journal Issue: 7; Other Information: (c) 2014 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; 60 APPLIED LIFE SCIENCES; DATASETS; IMAGE PROCESSING; NMR IMAGING; RADIOTHERAPY

Citation Formats

Lee, Danny, Pollock, Sean, Whelan, Brendan, Keall, Paul, and Kim, Taeho, E-mail: taeho4kim@gmail.com. Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI. United States: N. p., 2014. Web. doi:10.1118/1.4883882.
Lee, Danny, Pollock, Sean, Whelan, Brendan, Keall, Paul, & Kim, Taeho, E-mail: taeho4kim@gmail.com. Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI. United States. doi:10.1118/1.4883882.
Lee, Danny, Pollock, Sean, Whelan, Brendan, Keall, Paul, and Kim, Taeho, E-mail: taeho4kim@gmail.com. Tue . "Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI". United States. doi:10.1118/1.4883882.
@article{osti_22412528,
title = {Dynamic keyhole: A novel method to improve MR images in the presence of respiratory motion for real-time MRI},
author = {Lee, Danny and Pollock, Sean and Whelan, Brendan and Keall, Paul and Kim, Taeho, E-mail: taeho4kim@gmail.com},
abstractNote = {Purpose: In this work, the authors present a novel magnetic resonance imaging reconstruction method to improve the quality of MR images in the presence of respiratory motion for real-time thoracic image-guided radiotherapy. Methods: This new reconstruction method is called dynamic keyhole and utilizes a library of previously acquired, peripheral k-space datasets from the same (or similar) respiratory state in conjunction with central k-space datasets acquired in real-time. Internal or external respiratory signals are utilized to sort, match, and combine the two separate peripheral and central k-space datasets with respect to respiratory displacement, thereby reducing acquisition time and improving image quality without respiratory-related artifacts. In this study, the dynamic keyhole, conventional keyhole, and zero-filling methods were compared to full k-space acquisition (ground truth) for 60 coronal datasets acquired from 15 healthy human subjects. Results: For the same image-quality difference from the ground-truth image, the dynamic keyhole method reused 79% of the prior peripheral phase-encoding lines, while the conventional keyhole reused 73% and zero-filling 63% (p-value < 0.0001), corresponding to faster acquisition speed of dynamic keyhole for real-time imaging applications. Conclusions: This study demonstrates that the dynamic keyhole method is a promising technique for clinical applications such as image-guided radiotherapy requiring real-time MR monitoring of the thoracic region. Based on the results from this study, the dynamic keyhole method could increase the temporal resolution by a factor of five compared with full k-space methods.},
doi = {10.1118/1.4883882},
journal = {Medical Physics},
number = 7,
volume = 41,
place = {United States},
year = {Tue Jul 15 00:00:00 EDT 2014},
month = {Tue Jul 15 00:00:00 EDT 2014}
}