Quantification of phosphorus metabolites from chemical shift imaging spectra with corrections for point spread effects and B1 inhomogeneity
✍ Scribed by Joseph Murphy; Hong Jiang; Radka Stoyanova; Truman R. Brown
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 996 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
A method is described for quantifying phosphorus metabolites in tissue using spectra localized with surface coils and chemical shift imaging (CSI) and assuming that metabolites are uniformly distributed within a well‐defined volume. An analytical expression is developed that yields a single numerical correction factor that takes into account the excitation and receiver profiles of the coil, T~1~ saturation, and point spread effects associated with Fourier transformation of CSI data. An external phosphorus standard is used to calibrate instrument gain and the B~1~ profile of the coil. For spherical samples, point spread effects can modulate the signal intensities of three‐dimensional CSI spectra from ‐32% to +54%, depending on the voxel size. Measurements of phantoms of known concentrations showed systematic variations of ± 10% and random errors of ± 5%. We have used this method to measure the concentration of phosphocreatine in the thigh muscle of normal volunteers.