Basic study of less invasive high-intensity focused ultrasound (HIFU) in fetal therapy for twin reversed arterial perfusion (TRAP) sequence.
OBJECTIVE
The objective of the present study was to develop a high-intensity focused ultrasound (HIFU) transducer more suitable for clinical use in fetal therapy for twin reversed arterial perfusion (TRAP) sequence.


METHODS
We created a cooling and degassed water-circulating-type HIFU treatment device. HIFU was applied to renal branch vessels in three rabbits. Sequential HIFU irradiation contains a trigger wave, heating wave, and rest time. The duration of HIFU application was 10 s/course. Targeting could be achieved by setting the imaging probe in the center and placing the HIFU beam and imaging ultrasonic wave on the same axis.


RESULTS
We confirmed under sequential HIFU irradiation with a total intensity of 1.94 kW/cm(2) (spatial average temporal average intensity) that the vein and artery were occluded in all three rabbits.


CONCLUSIONS
Simultaneous occluding of the veins and arteries was confirmed with trigger waves and a resting phase using the HIFU transducer treatment device created for this study. Clinical application appears possible and may represent a promising option for fetal therapy involving TRAP sequence.
Department of Obstetrics and Gynecology, Showa University Northern Yokohama Hospital, Chigasaki-chuo, Tsuzuki-ku, Yokohama, Kanagawa, 224-8503, Japan. ichizuka@med.showa-u.ac.jp.
Kiyotake
K
Ichizuka
Department of Obstetrics and Gynecology, Showa University, School of Medicine, Tokyo, Japan.
Ryu
R
Matsuoka
Department of Obstetrics and Gynecology, Mito Red Cross Hospital, Mito, Japan.
Hiroko
H
Aoki
Department of Obstetrics and Gynecology, St. Marianna University, School of Medicine, Kawasaki, Japan.
Junichi
J
Hasegawa
Department of Obstetrics and Gynecology, Aiiku Hospital, Tokyo, Japan.
Takashi
T
Okai
Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.
Shin-Ichiro
S
Umemura
D000818:Animals; D004867:Equipment Design; D005260:Female; D046128:Fetal Therapies / Q000295:instrumentation* / Q000379:methods*; D005330:Fetofetal Transfusion / Q000628:therapy*; D057086:High-Intensity Focused Ultrasound Ablation / Q000295:instrumentation* / Q000379:methods*; D007668:Kidney / Q000098:blood supply; D011247:Pregnancy; D011817:Rabbits; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D012082:Renal Veins / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D018615:Ultrasonography, Doppler, Color
Fetal therapy; Flow occlusion; HIFU; TRAP sequence