Application of high-intensity focused ultrasound for fetal therapy: experimental study using an animal model of lower urinary tract obstruction.
OBJECTIVE
The purpose of this study is to investigate whether high-intensity focused ultrasound (HIFU) exposure is able to produce a fistula between the bladder and abdominal wall of a fetus with lower urinary tract obstruction (LUTO).


METHODS
We constructed a prototype HIFU transducer in combination with an imaging probe. HIFU was applied to the lower abdomen of a rabbit neonate that was complicated by LUTO as an experimental model to produce a fistula; HIFU was applied in a tank filled with degassed water. Exposed lesions were assessed by histological analysis at necropsy.


RESULTS
When HIFU was applied at 5.5 kW/cm(2) of spatial-peak temporal average intensity (SPTA), a fistula was created between the lower abdominal wall and the urinary bladder; urine gushed out from the bladder through the fistula within 60 s after HIFU exposure.


CONCLUSIONS
The findings suggest that fetal diseases such as LUTO can be non-invasively treated using HIFU exposure from even outside the maternal body, though this study was performed in a water tank.
Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8666, Japan.
Hiroko
H
Aoki
Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8666, Japan. k.ichizuka@me.com.
Kiyotake
K
Ichizuka
Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8666, Japan.
Mitsuyoshi
M
Ichihara
Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8666, Japan.
Ryu
R
Matsuoka
Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8666, Japan.
Junichi
J
Hasegawa
Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8666, Japan.
Takashi
T
Okai
Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.
Shinichirou
S
Umemura
Fetal therapy; HIFU; LUTO; Non-invasive