Abbreviated MRI for Preoperative Assessment of Breast Cancer: is Maximal Intensity Projection (MIP) of the First Post Contrast Acquisition Subtracted (Fast) Sequence Sufficient for Disease Evaluation?

OBJECTIVES

The aim of this study was to assess the diagnostic performance of abbreviated MRI (AMRI) using the maximal intensity projection (MIP) reconstruction of the first post-contrast acquisition subtracted (FAST) compared with MIP+FAST and full-protocol MRI (fpMRI) for the preoperative assessment of breast cancer (BC) in a biopsy-proven cancer population.

METHODS

In this monocentric retrospective study, two readers consensually assessed two AMRI protocols consisting of MIP reconstruction of the FAST (MIP) and MIP+FAST. 228 patients were included with a breast MRI performed between 2013 and 2014, 207 of them (90.8%) had biopsy-proven cancer with 256 lesions. Data of MIP and MIP+FAST were compared to full-protocol MRI (fpMRI) reading and to the reference standard including 6-month follow-up imaging and pathology as the reference.

RESULTS

MIP, MIP+FAST and fpMRI demonstrated a per-lesion sensitivity for BC detection of 87.5% (224/256, 95%CI: 82.9-91.3%) and 97.7% (250/256, 95-99.1%) and 98.4% (252/256, 96.1-99.6%), respectively with a statistical difference between MIP compared to MIP+FAST and fpMRI when considering confidence intervals. Per-lesion specificity was not different [MIP: 47.6% (10/21, 25.7-70.2%), MIP+FAST: 52.4% (11/21,29.8-74.3%, fpMRI: 66.7% (14/21, 43-85.4%)].

CONCLUSION

AMRI using only MIP is not accurate for the pre-operative assessment of BC due to lower sensitivity when compared to MIP+FAST and fpMRI. AMRI using the MIP+FAST acquisition in the preoperative setting seems promising as it could be used as the same protocol for both screening and staging in case of positive cases, without need for a recall fpMRI. This needs confirmation with cohort including higher rate of negative cases in order to evaluate the specificity.