MR signature matching (MRSIGMA) implementation for true real-time free-breathing volumetric imaging with sub-200 ms latency on an MR-Linac Journal Article


Authors: Siddiq, S.; Murray, V.; Tyagi, N.; Borman, P.; Gui, C.; Crane, C.; Wu, C.; Otazo, R.
Article Title: MR signature matching (MRSIGMA) implementation for true real-time free-breathing volumetric imaging with sub-200 ms latency on an MR-Linac
Abstract: Purpose: Develop a true real-time implementation of MR signature matching (MRSIGMA) for free-breathing 3D MRI with sub-200 ms latency on the Elekta Unity 1.5T MR-Linac. Methods: MRSIGMA was implemented on an external computer with a network connection to the MR-Linac. Stack-of-stars with partial kz sampling was used to accelerate data acquisition and ReconSocket was employed for simultaneous data transmission. Movienet network computed the 4D MRI motion dictionary and correlation analysis was used for signature matching. A programmable 4D MRI phantom was utilized to evaluate MRSIGMA with respect to a ground-truth translational motion reference. In vivo validation was performed on patients with pancreatic cancer, where 15 patients were employed to train Movienet and 7 patients to test the real-time implementation of MRSIGMA. Dice coefficients between real-time MRSIGMA and a retrospectively computed 4D reference were used to evaluate motion tracking performance. Results: Motion dictionary was computed in under 5 s. Signature acquisition and matching presented 173 ms latency on the phantom and 193 ms on patients. MRSIGMA presented a mean error of 1.3–1.6 mm for all phantom experiments, which was below the 2 mm acquisition resolution along the motion direction. The Dice coefficient over time between MRSIGMA and reference contours was 0.88 ± 0.02 (GTV), 0.87 ± 0.02(duodenum-stomach), and 0.78 ± 0.02(small bowel), demonstrating high motion tracking performance for both tumor and organs at risk. Conclusion: The real-time implementation of MRSIGMA enabled true real-time free-breathing 3D MRI with sub-200 ms imaging latency on a clinical MR-Linac system, which can be used for treatment monitoring, adaptive radiotherapy and dose accumulation mapping in tumors affected by respiratory motion. © 2024 International Society for Magnetic Resonance in Medicine.
Keywords: adult; pancreas cancer; nuclear magnetic resonance imaging; magnetic resonance imaging; monitoring; tumor volume; radiotherapy; correlation analysis; tumors; image quality; image processing; real time control; error; volumetric modulated arc therapy; gross tumor volume; phantoms; latent period; principal component analysis; real-time; linear accelerators; data acquisition; three-dimensional imaging; human; male; female; article; radiation oncologist; free breathing; motion analysis; deep learning; motion tracking; mr-linac; mri-guided radiotherapy; real- time; signature-matching; 4d mri; low-latency; low latency; real-time implementations; time-free; mr signature matching; real time free breathing volumetric imaging
Journal Title: Magnetic Resonance in Medicine
Volume: 92
Issue: 3
ISSN: 0740-3194
Publisher: John Wiley & Sons  
Date Published: 2024-09-01
Start Page: 1162
End Page: 1176
Language: English
DOI: 10.1002/mrm.30097
PUBMED: 38576131
PROVIDER: scopus
PMCID: PMC11209806
DOI/URL:
Notes: Article -- MSK Cancer Center Support Grant (P30 CA008748) acknowledged in PubMed and PDF -- MSK corresponding author is Saad Siddiq -- Source: Scopus
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MSK Authors
  1. Neelam Tyagi
    151 Tyagi
  2. Christopher   Crane
    202 Crane
  3. Can Wu
    19 Wu
  4. Chengcheng Gui
    21 Gui
  5. Syed Saad Siddiq
    5 Siddiq