Quantitative tissue sodium concentration mapping of normal rat brain

✍ Scribed by James D. Christensen; Bertrand J. Barrère; Fernando E. Boada; J. Michael Vevea; Keith R. Thulborn

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 840 KB
• Volume: 36
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/mrm.1910360115

✦ Synopsis

Abstract

A quantitative in vivo method for obtaining maps of tissue sodium concentration (TSC) by MRI is compared to the invasive, global ^22^Na radionuclide dilutional technique in the normal rat brain. The MR method uses a three‐dimensional projectional acquisition scheme to minimize signal losses from transverse relaxation. Internal calibration standards are used to convert the signal intensity into TSC after correction for B~1~ inhomogeneities by using the ratio of ^23^Na and ^1^H images obtained with identical B~1~ distributions and sensitivities at the two frequencies. Over the biological range of concentrations, the TSC, measured as the ratio of MR signals of ^23^Na and ^1^H, gives a linear response with concentration. In the normal rat brain, the mean TSC measured using the MRI method (TSC = 45 ± 4 m__M__, animals = 5) is not significantly different from the global ^22^Na radionuclide method (TSC = 49 ± 6 m__M__, animals = 7).