An MRI/US/x-ray compatible breast localization marker: in vivo evaluation.
OBJECTIVE
An in vivo evaluation of a new trimodality breast localization marker was performed with magnetic resonance imaging (MRI), ultrasound (US), x-ray, and histopathology. The evaluation of the marker in animal tests should help define its utility for surgical biopsy localization in humans.


METHODS
Five rabbits were used and sacrificed at 2 days, 1 week, 2 weeks, 4 weeks, and 7 weeks after marker implantation. The marker placement and tissue biopsies were performed under US guidance. MRI, US, and x-ray imaging were performed to monitor the contrast of the marker, track marker migration. The biologic compatibility of the marker was demonstrated by histopathologic analysis.


RESULTS
The contrast of the marker was clear and stable on each imaging modality over the 7-week study period. Acute inflammation was visible by 2 days after marker injection, with evidence of granulation tissue and angiogenesis at 2 weeks after implantation. A modest degree of chronic inflammation and angiogenesis remained evident at 4 weeks after procedure, and fibrosis persisted 7 weeks after procedure with no further tissue changes. These results suggest that the new marker is biocompatible and can remain interstitial for up to 7 weeks. Furthermore, very little marker migration was observed. On removal, the marker was found to be mechanically stable.


CONCLUSIONS
This in vivo animal study demonstrates that the new marker may be appropriate for in vivo human testing and as an alternative to traditional wire localization currently used for breast surgery.
Li
Yangmei
Y
Imaging Research, Sunnybrook and Women's College Health Sciences Centre, University of Toronto, Toronto, Ontario M4N 3M5, Canada.
Holloway
Claire M B
CM
Purcell
Carrie M
CM
Wang
Jianxiong
J
Plewes
Donald B
DB
D000818:Animals; D001706:Biopsy / Q000295:instrumentation* / Q000379:methods; D001940:Breast / Q000473:pathology*; D019544:Equipment Failure Analysis; D005260:Female; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008327:Mammography / Q000295:instrumentation* / Q000379:methods; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016217:Ultrasonography, Mammary / Q000295:instrumentation* / Q000379:methods