In vivo feasibility of image-guided transvaginal focused ultrasound therapy for the treatment of intracavitary fibroids.
OBJECTIVE
To determine the feasibility of uterine tissue ablation in vivo using a transvaginal focused ultrasound applicator guided by ultrasound imaging.


METHODS
Randomized in vivo animal study.


METHODS
Academic research environment.


METHODS
Healthy anesthetized sheep.


METHODS
Uterine treatment location was determined using a computerized targeting system. Five sonications 10 seconds in duration and averaging 2,000 W/cm(2) of focal ultrasound intensity were applied in each animal's uterus. Animals were euthanized either immediately or 2, 7, or 30 days post-treatment.


METHODS
Gross and microscopic analysis of the dissected uterus was used to quantitatively and qualitatively determine the ablated region and treatment side effects.


RESULTS
Treatments resulted in coagulative necrosis. Histopathological analysis showed that over 7 days, inflammatory cells appeared and smooth muscle bundles regenerated. By day 30, treated tissues healed and scar tissue formed. None of the animals showed abnormal behavior or medical problems. Complications in three animals were damage to the vaginal wall and colon, possibly due to inadequate applicator cooling and an empty bladder during treatment.


CONCLUSIONS
Transvaginal image-guided high-intensity focused ultrasound has potential for treating uterine fibroids. Further safety testing of this treatment will prepare it for human use.
Chan
Arthur H
AH
Department of Bioengineering, and Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA.
Fujimoto
Victor Y
VY
Moore
Donald E
DE
Held
Robert T
RT
Paun
Marla
M
Vaezy
Shahram
S
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D007889:Leiomyoma / Q000000981:diagnostic imaging* / Q000473:pathology; D009336:Necrosis; D011859:Radiography; D012756:Sheep; D014464:Ultrasonic Therapy / Q000379:methods*; D014463:Ultrasonography; D014594:Uterine Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology