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The effects of spatial sampling choices on MR temperature measurements
Author(s) -
Todd Nick,
Vyas Urvi,
de Bever Josh,
Payne Allison,
Parker Dennis L.
Publication year - 2011
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.22636
Subject(s) - sampling (signal processing) , image resolution , intensity (physics) , resolution (logic) , volume (thermodynamics) , temperature measurement , curvature , materials science , nuclear magnetic resonance , mathematics , optics , physics , detector , geometry , computer science , quantum mechanics , artificial intelligence
The purpose of this article is to quantify the effects that spatial sampling parameters have on the accuracy of magnetic resonance temperature measurements during high intensity focused ultrasound treatments. Spatial resolution and position of the sampling grid were considered using experimental and simulated data for two different types of high intensity focused ultrasound heating trajectories (a single point and a 4‐mm circle) with maximum measured temperature and thermal dose volume as the metrics. It is demonstrated that measurement accuracy is related to the curvature of the temperature distribution, where regions with larger spatial second derivatives require higher resolution. The location of the sampling grid relative temperature distribution has a significant effect on the measured values. When imaging at 1.0 × 1.0 × 3.0 mm 3 resolution, the measured values for maximum temperature and volume dosed to 240 cumulative equivalent minutes (CEM) or greater varied by 17% and 33%, respectively, for the single‐point heating case, and by 5% and 18%, respectively, for the 4‐mm circle heating case. Accurate measurement of the maximum temperature required imaging at 1.0 × 1.0 × 3.0 mm 3 resolution for the single‐point heating case and 2.0 × 2.0 × 5.0 mm 3 resolution for the 4‐mm circle heating case. Magn Reson Med, 2011. © 2010 Wiley‐Liss, Inc.