Irreversible change in the T1 temperature dependence with thermal dose using the proton resonance frequency‐T1 technique. Issue 4 (10th May 2012)

• Record Type: Journal Article
• Authors: Diakite, Mahamadou; Payne, Allison; Todd, Nick; Parker, Dennis L.
• Is Part Of: Magnetic resonance in medicine. Volume 69:Issue 4(2013:Apr.)
• Page Start: 1122
• Page End: 1130
• Publication Date: 2012-05-10
• Subjects: Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.24322
• Languages: English
• ISSNs: 0740-3194

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Denaturation of macromolecules within the tissues is believed to be the major factor contributing to the damage of tissues upon hyperthermia. As a result, the value of the spin‐lattice relaxation time <italic>T</italic><sub>1</sub> of the tissue water, which is related to the translational and rotational rates of water, represents an intrinsic probe for investigating structural changes in tissues at high temperature. Therefore, the goal of this work is to investigate whether the simultaneous measurement of temperature and <italic>T</italic><sub>1</sub> using a hybrid proton resonance frequency (PRF)‐<italic>T</italic><sub>1</sub> measurement technique can be used to detect irreversible changes in <italic>T</italic><sub>1</sub> that might be indicative of tissue damage. A new hybrid PRF‐<italic>T</italic><sub>1</sub> sequence was implemented based on the variable flip angle driven‐equilibrium single‐pulse observation (DESPO<italic>T</italic>)<sub>1</sub> method from a standard three dimensional segmented echo‐planar imaging sequence by alternating two flip angles from measurement to measurement. The structural changes of the heated tissue volumes were analyzed based on the derived <italic>T</italic><sub>1</sub> values and the corresponding PRF temperatures. Using the hybrid PRF‐<italic>T</italic><sub>1</sub> technique, we demonstrate that the change of spin lattice relaxation time <italic>T</italic><sub>1</sub> is reversible with temperature for low thermal dose (thermal dose ≤ 240 cumulative equivalent minutes [CEM] 43°C) and irreversible with temperature after significant accumulation of thermal dose in ex vivo chicken breast tissue. These results suggest that the hybrid PRF‐<italic>T</italic><sub>1</sub> method may be a potentially powerful tool to investigate the extent and mechanism of heat damage of biological tissues. Magn Reson Med 69:1122–1130, 2013. © 2012 Wiley Periodicals, Inc.</p> </abstract>