1. Feasibility of cardiac-synchronized quantitative T 1 and T 2 mapping on a hybrid 1.5 Tesla magnetic resonance imaging and linear accelerator system.
- Author
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Akdag O, Mandija S, van Lier ALHMW, Borman PTS, Schakel T, Alberts E, van der Heide O, Hassink RJ, Verhoeff JJC, Mohamed Hoesein FAA, Raaymakers BW, and Fast MF
- Abstract
Background and Purpose: The heart is important in radiotherapy either as target or organ at risk. Quantitative T
1 and T2 cardiac magnetic resonance imaging (qMRI) may aid in target definition for cardiac radioablation, and imaging biomarker for cardiotoxicity assessment. Hybrid MR-linac devices could facilitate daily cardiac qMRI of the heart in radiotherapy. The aim of this work was therefore to enable cardiac-synchronized T1 and T2 mapping on a 1.5 T MR-linac and test the reproducibility of these sequences on phantoms and in vivo between the MR-linac and a diagnostic 1.5 T MRI scanner., Materials and Methods: Cardiac-synchronized MRI was performed on the MR-linac using a wireless peripheral pulse-oximeter unit. Diagnostically used T1 and T2 mapping sequences were acquired twice on the MR-linac and on a 1.5 T MR-simulator for a gel phantom and 5 healthy volunteers in breath-hold. Phantom T1 and T2 values were compared to gold-standard measurements and percentage errors (PE) were computed, where negative/positive PE indicate underestimations/overestimations. Manually selected regions-of-interest were used for in vivo intra/inter scanner evaluation., Results: Cardiac-synchronized T1 and T2 qMRI was enabled after successful hardware installation on the MR-linac. From the phantom experiments, the measured T1 /T2 relaxation times had a maximum percentage error (PE) of -4.4%/-8.8% on the MR-simulator and a maximum PE of -3.2%/+8.6% on the MR-linac. Mean T1 /T2 of the myocardium were 1012 ± 34/51 ± 2 ms on the MR-simulator and 1034 ± 42/51 ± 1 ms on the MR-linac., Conclusions: Accurate cardiac-synchronized T1 and T2 mapping is feasible on a 1.5 T MR-linac and might enable novel plan adaptation workflows and cardiotoxicity assessments., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Eveline Alberts is an employee of Philips Healthcare., (© 2022 The Authors.)- Published
- 2022
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