Quantification techniques to minimize the effects of native T1 variation and B1 inhomogeneity in dynamic contrast-enhanced MRI of the breast at 3 T

The variation of the native T1 (T10) of different tissues and B1 transmission-field inhomogeneity at 3 T are major contributors of errors in the quantification of breast dynamic contrast-enhanced MRI. To address these issues, we have introduced new enhancement indices derived from saturation-recovery snapshot-FLASH (SRSF) images. The stability of the new indices, i.e., the SRSF enhancement factor (EFSRSF) and its simplified version (EF'SRSF) with respect to differences in T10 and B1 inhomogeneity was compared against a typical index used in breast dynamic contrast-enhanced MRI, i.e., the enhancement ratio (ER), by using computer simulations. Imaging experiments with Gd-DTPA-doped gel phantoms and a female volunteer were also performed. A lower error was observed in the new indices compared to enhancement ratio in the presence of typical T10 variation and B1 inhomogeneity. At changes of relaxation rate (R1) of 8 s-1, the differences between a T10 of 1266 and 566 ms are <1, 12, and 58%, respectively, for EFSRSF, EF'SRSF, and ER, whereas differences of 20, 8, and 51%, respectively, result from a 50% B1 field reduction at the same R1. These quantification techniques may be a solution to minimize the effect of T10 variation and B1 inhomogeneity on dynamic contrast-enhanced MRI of the breast at 3 T. Magn Reson Med, 2012. (C) 2011 Wiley Periodicals, Inc.