MR imaging-guided focused ultrasound surgery of fibroadenomas in the breast: a feasibility study.
OBJECTIVE
To test the feasibility of noninvasive magnetic resonance (MR) imaging-guided focused ultrasound surgery (FUS) of benign fibroadenomas in the breast.


METHODS
Eleven fibroadenomas in nine patients under local anesthesia were treated with MR imaging-guided FUS. Based on a T2-weighted definition of target volumes, sequential sonications were delivered to treat the entire target. Temperature-sensitive phase-difference-based MR imaging was performed during each sonication to monitor focus localization and tissue temperature changes. After the procedure, T2-weighted and contrast material-enhanced T1-weighted MR imaging were performed to evaluate immediate and long-term effects.


RESULTS
Thermal imaging sequences were improved over the treatment period, with 82% (279 of 342) of the hot spots visible in the last seven treatments. The MR imager was used to measure temperature elevation (12.8 degrees -49.9 degrees C) from these treatments. Eight of the 11 lesions treated demonstrated complete or partial lack of contrast material uptake on posttherapy T1-weighted images. Three lesions showed no marked decrease of contrast material uptake. This lack of effective treatment was most likely due to a lower acoustic power and/or patient movement that caused misregistration. No adverse effects were detected, except for one case of transient edema in the pectoralis muscle 2 days after therapy.


CONCLUSIONS
MR imaging-guided FUS can be performed to noninvasively coagulate benign breast fibroadenomas.
Hynynen
K
K
Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA. kullervo@bwh.harvard.edu
Pomeroy
O
O
Smith
D N
DN
Huber
P E
PE
McDannold
N J
NJ
Kettenbach
J
J
Baum
J
J
Singer
S
S
Jolesz
F A
FA
D000328:Adult; D001833:Body Temperature Regulation / Q000502:physiology; D001943:Breast Neoplasms / Q000175:diagnosis / Q000628:therapy*; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D018226:Fibroadenoma / Q000175:diagnosis / Q000628:therapy*; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D011446:Prospective Studies; D014159:Transducers; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000295:instrumentation*