In vivo quantitative MRI: T 1 and T 2 measurements of the human brain at 0.064 T

• Published in: Magma (New York, N.Y.) N.Y.), 2023-07, Vol.36 (3), p.487
• Main Authors: Jordanova, Kalina V, Martin, Michele N, Ogier, Stephen E, Poorman, Megan E, Keenan, Kathryn E
• Format: Article
• Language: English
• Subjects: Brain - diagnostic imaging; Brain - pathology; Gray Matter - diagnostic imaging; Humans; Magnetic Resonance Imaging - methods; Magnetic Resonance Spectroscopy; White Matter - diagnostic imaging
• ISSN: 1352-8661

To measure healthy brain [Formula: see text] and [Formula: see text] relaxation times at 0.064 T. [Formula: see text] and [Formula: see text] relaxation times were measured in vivo for 10 healthy volunteers using a 0.064 T magnetic resonance imaging (MRI) system and for 10 test samples on both the MRI and a separate 0.064 T nuclear magnetic resonance (NMR) system. In vivo [Formula: see text] and [Formula: see text] values are reported for white matter (WM), gray matter (GM), and cerebrospinal fluid (CSF) for automatic segmentation regions and manual regions of interest (ROIs). [Formula: see text] sample measurements on the MRI system were within 10% of the NMR measurement for 9 samples, and one sample was within 11%. Eight [Formula: see text] sample MRI measurements were within 25% of the NMR measurement, and the two longest [Formula: see text] samples had more than 25% variation. Automatic segmentations generally resulted in larger [Formula: see text] and [Formula: see text] estimates than manual ROIs. [Formula: see text] and [Formula: see text] times for brain tissue were measured at 0.064 T. Test samples demonstrated accuracy in WM and GM ranges of values but underestimated long [Formula: see text] in the CSF range. This work contributes to measuring quantitative MRI properties of the human body at a range of field strengths.