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Regional neonatal brain absolute thermometry by 1 H MRS
Author(s) -
Bainbridge Alan,
Kendall Giles S.,
Vita Enrico De,
Hagmann Cornelia,
Kapetanakis Andrew,
Cady Ernest B.,
Robertson Nicola J.
Publication year - 2013
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.2879
Subject(s) - nuclear medicine , creatine , white matter , choline , chemistry , nuclear magnetic resonance , medicine , magnetic resonance imaging , physics , radiology
Therapeutic hypothermia is standard care for infants with moderate to severe encephalopathy. 1 H MRS thermometry (MRSt) measures regional brain absolute temperature using the temperature‐dependent water chemical shift. This study evaluates the clinical feasibility of MRSt in human neonates, and correlates white matter (WM) and thalamus (Thal) MRSt with conventional rectal temperature ( T rectal ) measurement. Fifty‐six infants born at term underwent perinatal MRSt for suspected hypoxic–ischaemic brain injury and 33 infants born preterm had MRSt at a term‐equivalent age; 56 of the 89 had T rectal measured after MRSt of either a Thal or posterior WM voxel, or both. MRSt used point‐resolved spectroscopy (no water suppression; TR = 1370 ms; TE = 288 ms; 1.5 × 1.5 × 1.5 cm 3 Thal and 1.1 × 1.3 × 1.4 cm 3 WM voxels). Time domain data were phase and frequency corrected before summation and motion‐corrupted data were excluded from further analysis using simple criteria [preprocessing + quality assurance (QA)]. Two published water temperature‐dependence calibrations [both using cerebral creatine (Cr), choline (Cho) and N ‐acetylaspartate (Naa) as independent reference peaks] were compared. The temperature measurements derived from Cr, Cho and Naa were combined to give a single amplitude‐weighted combination temperature ( T AWC ). WM and Thal T AWC correlated linearly with T rectal (Thal slope, 0.82 ± 0.04, R 2 = 0.85, p < 0.05; WM slope, 0.95 ± 0.04, R 2 = 0.78, p < 0.05). Preprocessing + QA improved the correlation between WM T AWC and T rectal ( R 2 increased from 0.27 to 0.78, p < 0.001). Both calibration datasets showed specific inconsistencies between the temperatures calculated using Cr, Cho and Naa reference peaks when applied to this neonatal dataset. Neonatal MRSt is clinically feasible. Preprocessing + QA improved MRSt reliability in WM. The consideration of MRSt calibration internal biases is necessary before combining MRSt temperatures from multiple reference peaks to obtain T AWC . Copyright © 2012 John Wiley & Sons, Ltd.