Feasibility of breast MRI after sentinel procedure for breast cancer with superparamagnetic tracers

Eur J Surg Oncol. 2018 Jan;44(1):74-79. doi: 10.1016/j.ejso.2017.11.016. Epub 2017 Nov 26.


Rationale: The gold standard for detection of axillary sentinel lymph nodes uses injection of a radioisotope (99Tc Nanocoll). As an alternative to this method, a magnetometer detecting the superparamagnetic tracer Sienna+® can be applied for detection of sentinel lymph nodes. The goal of this study was to determine whether interpretation of breast MRI is impaired by Sienna+® tracer residues in the operated breast and axillary lymph nodes after a sentinel procedure using this tracer.

Patients and methods: 34 patients who received the Sienna+® tracer for marking the sentinel node were invited to undergo a follow-up breast MRI. Native MR images were obtained from breast and axilla. The breast MRIs were evaluated by two independent breast radiologists for Sienna+® tracer related artefacts and for the degree of impairment of the MR imaging.

Results: 24 of the 34 invited patients took part in this study. The mean time since injection of Sienna+® was 42 months (40.6-45.4 months). Two patients had bilateral surgery with injections in both breasts, leading to a total of 26 separate cases. One case had to be excluded due to breathing artefacts. In 10 cases (40%), impaired imaging was found. In three cases (12%), the MRI scan reading was impossible due to Sienna+® tracer residues, the other 12 cases (48%) showed no restriction. In the subgroup of patients treated with breast conserving surgery, tracer residue artefacts were found in 13 of 17 patients (76.5%).

Conclusion: To our knowledge, in this study for the first time MR feasibility after Sienna injection was investigated. Sienna+® impaired breast MRI after a mean follow-up time of 42 months in half of the cases. Further research is needed to investigate time and field-strength dependency of tracer detectability as well as the diagnostic impact of these artifacts on contrast-enhanced imaging in a clinical setting.

Keywords: Breast cancer; MR imaging; SNB; Sentinel node biopsy.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Breast Neoplasms / diagnosis*
  • Breast Neoplasms / secondary
  • Feasibility Studies
  • Female
  • Follow-Up Studies
  • Humans
  • Magnetic Resonance Imaging / methods*
  • Magnetite Nanoparticles*
  • Middle Aged
  • Neoplasm Staging / methods*
  • Sentinel Lymph Node / diagnostic imaging*
  • Sentinel Lymph Node / pathology
  • Sentinel Lymph Node Biopsy / methods*
  • Time Factors


  • Magnetite Nanoparticles