Real-time 4D MRI using MR signature matching (MRSIGMA) on a 1.5T MR-Linac system Journal Article
| Authors: | Wu, C.; Murray, V.; Siddiq, S. S.; Tyagi, N.; Reyngold, M.; Crane, C.; Otazo, R. |
| Article Title: | Real-time 4D MRI using MR signature matching (MRSIGMA) on a 1.5T MR-Linac system |
| Abstract: | Objective. To develop real-time 4D MRI using MR signature matching (MRSIGMA) for volumetric motion imaging in patients with pancreatic cancer on a 1.5T MR-Linac system.Approach. Two consecutive MRI scans with 3D golden-angle radial stack-of-stars acquisitions were performed on ten patients with inoperable pancreatic cancer. The complete first scan (905 angles) was used to compute a 4D motion dictionary including ten pairs of 3D motion images and signatures. The second scan was used for real-time imaging, where each angle (275 ms) was processed separately to match it to one of the dictionary entries. The complete second scan was also used to compute a 4D reference to assess motion tracking performance.Dicecoefficients of the gross tumor volume (GTV) and two organs-at-risk (duodenum-stomach and small bowel) were calculated between signature matching and reference. In addition, volume changes, displacements, center of mass shifts, andDicescores over time were calculated to characterize motion.Main results. Total imaging latency of MRSIGMA (acquisition + matching) was less than 300 ms. TheDicecoefficients were 0.87 ± 0.06 (GTV), 0.86 ± 0.05 (duodenum-stomach), and 0.85 ± 0.05 (small bowel), which indicate high accuracy (high mean value) and low uncertainty (low standard deviation) of MRSIGMA for real-time motion tracking. The center of mass shift was 3.1 ± 2.0 mm (GTV), 5.3 ± 3.0 mm (duodenum-stomach), and 3.4 ± 1.5 mm (small bowel). TheDicescores over time (0.97 ± [0.01-0.03]) were similarly high for MRSIGMA and reference scans in all the three contours.Significance. This work demonstrates the feasibility of real-time 4D MRI using MRSIGMA for volumetric motion tracking on a 1.5T MR-Linac system. The high accuracy and low uncertainty of real-time MRSIGMA is an essential step towards continuous treatment adaptation of tumors affected by real-time respiratory motion and could ultimately improve treatment safety by optimizing ablative dose delivery near gastrointestinal organs. Creative Commons Attribution license. |
| Keywords: | pancreatic neoplasms; nuclear magnetic resonance imaging; magnetic resonance imaging; radiotherapy; diagnostic imaging; pancreas carcinoma; pancreas tumor; motion; real-time; pancreatic carcinoma; organs at risk; humans; human; motion tracking; mr-linac; 4d mri |
| Journal Title: | Physics in Medicine and Biology |
| Volume: | 68 |
| Issue: | 18 |
| ISSN: | 0031-9155 |
| Publisher: | IOP Publishing Ltd |
| Date Published: | 2023-09-21 |
| Start Page: | 185015 |
| Language: | English |
| DOI: | 10.1088/1361-6560/acf3cc |
| PUBMED: | 37619588 |
| PROVIDER: | scopus |
| PMCID: | PMC10513779 |
| DOI/URL: | |
| Notes: | Article -- MSK Cancer Center Support Grant (P30 CA008748) acknowledged in PubMed and PDF -- MSK corresponding author is Can Wu -- Source: Scopus |
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