|Title:||Dynamic keyhole: a novel method to improve MR images in the presence of respiratory motion for real-time MRI|
|Publisher:||American Institute of Physics|
|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-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.|
|Type of Work:||Article|
|Type of Publication:||Pre-print|
|Appears in Collections:||Research Papers and Publications. Sydney Medical School|
|Lee_2014.pdf||1.82 MB||Adobe PDF|
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