title: Pulsed high-intensity focused ultrasound enhances the relative permeability of the blood-tumor barrier in a glioma-bearing rat model.
abstract: The use of pulsed high-intensity focused ultrasound (HIFU) with an ultrasound contrast agent (UCA) has been shown to disrupt the blood-brain barrier (BBB) noninvasively and reversibly in the targeted regions. This study evaluated the relative permeability of the blood-tumor barrier (BTB) after sonication by pulsed HIFU. Entry into the brain of chemotherapeutic agents is impeded by the BBB even though the permeability of this barrier may be partially reduced in the presence of a brain tumor. F98 glioma-bearing rats were injected intravenously with Evans blue (EB) with or without BTB disruption induced by pulsed HIFU. Sonication was applied at an ultrasound frequency of 1 MHz with a 5% duty cycle, and a repetition frequency of 1 Hz. The accumulation of EB in brain tumor and the tumor-to-contralateral brain ratio of EB were highest after pulsed HIFU exposure. Sonication followed by EB injection showed a tumor-to-contralateral brain ratio in the target tumors which was about 2 times that of the control tumors. This research demonstrates that pulsed HIFU enhances the relative permeability of the BTB in glioma- bearing rats. The results of this pilot study support the idea that further evaluation of other treatment strategies, such as HIFU exposure in addition to combined chemotherapy or repeated pulsed HIFU exposure to increase delivery of drugs into brain tumors, might be useful.
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, School of Biomedical Science and Engineering, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Feng-Yi
authors.initials: FY
authors.lastname: Yang
authors.forename: Guan-Liang
authors.initials: GL
authors.lastname: Lin
authors.forename: Shih-Cheng
authors.initials: SC
authors.lastname: Horng
authors.forename: Tien-Kuei
authors.initials: TK
authors.lastname: Chang
authors.forename: Shih-Yen
authors.initials: SY
authors.lastname: Wu
authors.forename: Tai-Tong
authors.initials: TT
authors.lastname: Wong
authors.forename: Hsin-Ell
authors.initials: HE
authors.lastname: Wang
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D001835:Body Weight; D001923:Brain Chemistry / Q000528:radiation effects; D001932:Brain Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000628:therapy*; D002199:Capillary Permeability / Q000528:radiation effects; D004195:Disease Models, Animal; D016503:Drug Delivery Systems; D005070:Evans Blue; D005910:Glioma / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000628:therapy*; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D006651:Histocytochemistry; D008279:Magnetic Resonance Imaging; D008297:Male; D051381:Rats; D011916:Rats, Inbred F344; D014463:Ultrasonography
chemical_list: D005070:Evans Blue