An anatomically realistic temperature phantom for radiofrequency heating measurements. Issue 1 (18th February 2014)

• Record Type: Journal Article
• Authors: Graedel, Nadine N.; Polimeni, Jonathan R.; Guerin, Bastien; Gagoski, Borjan; Wald, Lawrence L.
• Is Part Of: Magnetic resonance in medicine. Volume 73:Issue 1(2015:Jan.)
• Page Start: 442
• Page End: 450
• Publication Date: 2014-02-18
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.25123
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mrm25123-sec-0001" sec-type="section"> <title>Purpose</title> <p>An anthropomorphic phantom with realistic electrical properties allows for a more accurate reproduction of tissue current patterns during excitation. A temperature map can then probe the worst‐case heating expected in the unperfused case. We describe an anatomically realistic human head phantom that allows rapid three‐dimensional (3D) temperature mapping at 7T.</p> </sec> <sec id="mrm25123-sec-0002" sec-type="section"> <title>Methods</title> <p>The phantom was based on hand‐labeled anatomical imaging data and consists of four compartments matching the corresponding human tissues in geometry and electrical properties. The increases in temperature resulting from radiofrequency excitation were measured with MR thermometry using a temperature‐sensitive contrast agent (TmDOTMA<sup>−</sup>) validated by direct fiber optic temperature measurements.</p> </sec> <sec id="mrm25123-sec-0003" sec-type="section"> <title>Results</title> <p>Acquisition of 3D temperature maps of the full phantom with a temperature accuracy better than 0.1°C was achieved with an isotropic resolution of 5 mm and acquisition times of 2–4 minutes.</p> </sec> <sec id="mrm25123-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Our results demonstrate the feasibility of constructing anatomically realistic phantoms with complex geometries incorporating the ability to measure accurate temperature maps in the phantom. The anthropomorphic temperature phantom is expected to provide a useful tool for the evaluation of the heating effects of both conventional and parallel transmit pulses and help validate electromagnetic and temperature simulations. Magn Reson Med 73:442–450, 2015. © 2014 Wiley Periodicals, Inc.</p> </sec> </abstract>