Analysis of the magnitude of susceptibility effects in the brains of pediatric patients

The analysis of susceptibility effects in vivo in various pathologic conditions has been described. The method is based on the production of phase difference maps between the phases of the voxels of two partial saturation images, in one of which data acquisition is delayed relative to the other. (The delays used in this work were 80, 120, and 160 msec). The study reported here discusses the level of changes seen in brain of pediatric patients (analyzing 30 cases). The complexity of the effects seen is greater than in adults and determination of where the measurements are to be made more difficult. At least three measurements of field difference were made in each case. Since susceptibility artifacts affect the quality of spectroscopic results, extensive presence of hemorrhage means that spatial localization in all three planes is needed to avoid erroneous pH and other measurements due to the physical distributions of metabolites (most particularly Pi and PCr) through the regions of varying field close to susceptibility changes resulting in incorrect chemical shifts. The authors use a three-dimensional phase encoding method