Breast MRI at 3.0 T in a high-risk familial breast cancer screening cohort: comparison with 1.5 T screening studies

The sensitivity of X-ray mammography for the detection of breast malignancy in younger females is lower than that of breast MRI; consequently, guidelines recommend annual MRI for patients with a significantly elevated lifetime risk. The improved signal-to-noise ratio obtainable at 3.0 T should result in data superior to those obtainable at 1.5 T. However, breast imaging on higher field strength systems poses specific problems. As a result, caution has been urged in the implementation of breast MRI at 3.0 T. The aim of this study was to determine if it is appropriate to use 3.0 T MRI in the screening of patients by comparing the summary statistics achieved by this 3.0 T MRI programme against the published results of 1.5 T screening studies.

Over a 20-month period, 291 patients referred with an elevated familial risk of breast cancer were examined at 3.0 T. Resulting images were scored based on the Royal College of Radiologists Breast Group imaging classification. The reference standard was a combination of histology and follow-up imaging.

Follow-up data were available in 267 patients. Analysis revealed positive and negative post-test probabilities of 28% [95% confidence intervals (CI); range, 10-60%] and 1% (95% CI; range, 0-2%), respectively. These results compared favourably against those of a recent meta-analysis [25.3% (95% CI; range, 18.4-33.8%) and 0.4% (95% CI; range, 0.2-0.9%), respectively].

Given the similar summary statistics between this work and the 1.5 T results, it would appear that screening of high-risk patients at 3.0 T has potential. Further studies should be undertaken to verify this result.