MR imaging-guided focused US ablation of breast cancer: histopathologic assessment of effectiveness-- initial experience.
OBJECTIVE
To evaluate the effectiveness of noninvasive magnetic resonance (MR) imaging-guided focused ultrasonographic (US) ablation of breast carcinomas.


METHODS
Before undergoing tumor resection, 12 patients with invasive breast carcinomas were treated with MR imaging-guided focused US ablation consisting of multiple sonications of targeted points that were monitored with temperature-sensitive MR imaging. The patients were treated with either one of two focused US systems. The effectiveness of the treatment was determined at histopathologic analysis of the resected mass that was performed to determine the volumes of necrosed and residual tumor. Complications resulting from the procedure were assessed by means of questionnaires, medical examinations, and MR image analysis.


RESULTS
US ablation was well tolerated by the patients, and with the exception of minor skin burns in two patients, no complications occurred. Histopathologic analysis of resected tumor sections enabled quantification of the amount of necrosed and residual tumor and visualization of the surrounding hemorrhage. In three patients treated with one of the US systems, a mean of 46.7% of the tumor was within the targeted zone and a mean of 43.3% of the cancer tissue was necrosed. In nine patients treated with the other US system, a mean of 95.6% of the tumor was within the targeted zone and a mean of 88.3% of the cancer tissue was necrosed. Residual tumor was identified predominantly at the periphery of the tumor mass; this indicated the need to increase the total targeted area (ie, with an increased number of sonications).


CONCLUSIONS
Thermal coagulation of small breast tumors by means of MR imaging-guided focused US appears to be a promising noninvasive ablation procedure.
Gianfelice
David
D
Department of Radiology, Hôpital Saint-Luc du Centre Hospitalier de l'Université de Montréal, 1058 St-Denis, Montreal, Quebec, Canada H2X 3J4. yvan.boulanger@umontreal.ca
Khiat
Abdesslem
A
Amara
Mourad
M
Belblidia
Assia
A
Boulanger
Yvan
Y
D001940:Breast / Q000473:pathology; D001943:Breast Neoplasms / Q000473:pathology / Q000628:therapy*; D018270:Carcinoma, Ductal, Breast / Q000473:pathology / Q000628:therapy*; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D014464:Ultrasonic Therapy
D003287:Contrast Media; D019786:Gadolinium DTPA