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Proceedings Paper

MR mapping of temperature and perfusion for hyperthermia therapy
Author(s): Waldemar Wlodarczyk; Julia Vlad; Thomas Lange; Peter Wust; Roland Felix
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Paper Abstract

The promising results, recently obtained in phantom experiments employing the MR-based proton resonance frequency (PRF) method as a non-invasive tool for the temperature monitoring of hyperthermia therapy, are not easily reproduced in vivo. One of the reasons is the impact of perfusion changes on the PRF-measured temperature. In our experiments in vivo, heat was supplied on one side of the volunteers knee or pelvis by a rubber hose with circulating warm water (50iC). The PRF method was calibrated by the constant temperature sensitivity of pure water of 0.011 ppm/iC. MR mapping of perfusion changes was based on T2*-weighted tracking of the first-pass kinetics of contrast agent. The hemodynamic parameters of regional blood volume (rBV) and mean transit time (MTT) were extracted by fitting pixel-by-pixel the first- pass kinetics to the gamma-variate model. Special attention was directed to improve a quality of the automatic non-linear fit at low signal-to-noise values. The distributions of PRF- based temperature changes show large areas of apparently high temperature elevations (exceeding 10iC) in regions close to the heat source, and others with just as large temperature decays in more distant regions. Areas of apparently high temperature elevations correlate with areas of blood flow increase and vice versa. In conclusion, the visible heat- induced PRF changes in vivo are primarily perfusion changes, which mask the much smaller true temperature changes.

Paper Details

Date Published: 21 May 2001
PDF: 8 pages
Proc. SPIE 4321, Medical Imaging 2001: Physiology and Function from Multidimensional Images, (21 May 2001); doi: 10.1117/12.428157
Show Author Affiliations
Waldemar Wlodarczyk, Virchow Klinikum/Humboldt-Univ. zu Berlin (Germany)
Julia Vlad, Virchow Klinikum/Humboldt-Univ. zu Berlin (Germany)
Thomas Lange, Virchow Klinikum/Humboldt-Univ. zu Berlin (Germany)
Peter Wust, Virchow Klinikum/Humboldt-Univ. zu Berlin (Germany)
Roland Felix, Virchow Klinikum/Humboldt-Univ. zu Berlin (Germany)

Published in SPIE Proceedings Vol. 4321:
Medical Imaging 2001: Physiology and Function from Multidimensional Images
Chin-Tu Chen; Anne V. Clough, Editor(s)

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