Comparison of 1.5T and 3T in assessment of suspicious breast lesions

Introduction

MRI at 3T has advantages of increased spatial and temporal resolution but with known transmit field inhomogeneity problems. The objective of this study is to compare the confidence in characterising the breast lesions in 1.5T and 3T MRI examinations performed and to compare the conspicuity of the lesions.

Materials and methods

Patients referred for a diagnostic MRI examination as part of their clinical work-up for a suspicious lesion or for preoperative staging were recruited into this study following informed consent. The MRI was undertaken on a 1.5T GE CVi/NVi (Milwaukee, WI, USA) and a 3T Philips Achieva (Best, the Netherlands). T2W, dynamic T1W (voxel size 0.85 x 1.19 x 2 mm - 1.5 T MRI, and 0.6 x 0.6 x 2 mm - 3T MRI) and high-resolution fat-suppressed T1W postcontrast sequences (single-dose contrast) were carried out. The confidence level in morphology and contrast kinetics (three-point scale) and conspicuity for each lesion (five-point scale, -2 to +2) was assessed by a single observer (SKAR).

Results

Seventeen patients were included in the study. Eleven patients had one or more lesions, giving 22 lesions. The confidence level in assessing morphology was high in 16/22 and 19/22 and in assessing contrast kinetics was high in 12/22 and 16/22 in 1.5T and 3T examinations, respectively. The mean and standard deviation of the conspicuity score are 1.09 ± 0.88 for 3T.

Conclusions

The confidence in characterising and conspicuity of the breast lesions is improved and no lesions identified at 1.5T were missed at 3T MRI. 3T MRI can be used safely in clinical practice.