Abstract
Purpose: to determine the expected range of NMR relaxation times (T1 and T2) in the neonatal brain at 7 Tesla.
Methods: Data was acquired in a total of 40 examinations on infants in natural sleep. The cohort included 34 unique subjects with postmenstrual age (PMA) range 33 -52 weeks and contained a mix of healthy individuals and those with clinical concerns. Single slice T1 and T2 mapping protocols were used to provide measurements in white matter, cortex, cerebellum and deep grey matter. Automatic image segmentation of a separate T2 weighted brain volume was used to define regions of interest for analysis.
Results: Linear regression was used to estimate relaxation times at term equivalent age (40 weeks PMA). T_1^40wk with 95% confidence intervals was measured to be 2933 [2893, 2972] ms in white matter; 2653 [2604, 2701] ms in cerebellum; and 2486 [2439, 2532] ms in basal ganglia. T_2^40wk was estimated as 119 [116, 121] ms in white matter; 99 [96, 102] ms in cerebellum; and 90 [89,92] ms in basal ganglia. Most tissue relaxation times showed a significant negative correlation with PMA, with the strongest correlation seen in cerebellum.
Conclusions: We describe neonatal brain tissue and age specific T1 and T2 relaxation values at 7 Tesla. The presented values differ substantially from both adult values at 7T and neonate values measured at lower field strengths, and will be essential for pulse sequence optimization for neonatal studies.
Methods: Data was acquired in a total of 40 examinations on infants in natural sleep. The cohort included 34 unique subjects with postmenstrual age (PMA) range 33 -52 weeks and contained a mix of healthy individuals and those with clinical concerns. Single slice T1 and T2 mapping protocols were used to provide measurements in white matter, cortex, cerebellum and deep grey matter. Automatic image segmentation of a separate T2 weighted brain volume was used to define regions of interest for analysis.
Results: Linear regression was used to estimate relaxation times at term equivalent age (40 weeks PMA). T_1^40wk with 95% confidence intervals was measured to be 2933 [2893, 2972] ms in white matter; 2653 [2604, 2701] ms in cerebellum; and 2486 [2439, 2532] ms in basal ganglia. T_2^40wk was estimated as 119 [116, 121] ms in white matter; 99 [96, 102] ms in cerebellum; and 90 [89,92] ms in basal ganglia. Most tissue relaxation times showed a significant negative correlation with PMA, with the strongest correlation seen in cerebellum.
Conclusions: We describe neonatal brain tissue and age specific T1 and T2 relaxation values at 7 Tesla. The presented values differ substantially from both adult values at 7T and neonate values measured at lower field strengths, and will be essential for pulse sequence optimization for neonatal studies.
| Original language | English |
|---|---|
| Journal | Magnetic resonance in medicine |
| Publication status | Accepted/In press - 26 Nov 2024 |