Combined staging at one stop using MR mammography: evaluation of an extended protocol to screen for distant metastasis in primary breast cancer - initial results and diagnostic accuracy in a prospective study.

ABSTRACT

PURPOSE: Accurate staging of primary breast cancer is essential for the therapeutic approach. Modern whole-body MR scanners would allow local and distant staging during a single examination. Accordingly, we designed a dedicated protocol for this purpose and prospectively evaluated the diagnostic accuracy. MATERIALS AND METHODS: 65 consecutive breast cancer patients underwent pre-therapeutic MRI (1.5 T). A bilateral breast protocol (axial T1w/GRE dynamic contrast-enhanced, T2w/TSE; TA 10 min) was extended to screen for distant metastasis at one stop without repositioning (coronal T2w/HASTE, T1w/VIBE; FOV thorax, abdomen and spine; TA 90 sec; multichannel surface coils). The standard of reference was S3 guideline-compliant staging examinations. Global assessment regarding the presence of distant metastasis was performed independently by two experienced and blinded radiologists (five-level confidence score). Inter-rater agreement (weighted kappa) and observer scoring were analyzed (contingency tables). RESULTS: The prevalence of synchronous metastases was 7.7 % (n = 5). The protocol enabled global assessment regarding the presence of distant metastasis with high accuracy (sensitivity 100 %; specificity 98.3 %) and inter-rater agreement (kappa 0.92). CONCLUSION: Applying the extended MRI protocol, accurate screening for distant metastasis was possible in combination with a dedicated breast examination.