Hirokawa Tomihiko, Karshafian Raffi, Pavlin Charles J, Burns Peter N
Department of Medical Biophysics, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
J Ultrasound Med. 2007 Jun;26(6):731-8. doi: 10.7863/jum.2007.26.6.731.
The purpose of this study was to investigate the presence and duration of vascular permeability changes induced by the combination of ultrasound and an intravascular microbubble contrast agent in the rabbit eye.
Five eyes were studied in 8 anaesthetized rabbits. Insonation was performed with a diagnostic B-mode system (center frequency = 2 MHz; mechanical index [MI] = 0.2 and 1.7) for 5 minutes after administration of perflutren microbubbles (0.07 mL/kg). Fluorescein fundus angiography was performed before and 3 minutes after insonation; at 6 minutes, color fundus photography was used to assess the dye leakage, bleeding, and alteration of the diameter of fundus vessels.
Alteration of fundus vessel diameters was observed in 1 of 5 cases at a low MI and in 4 of 5 cases at a higher MI. In 1 case, leakage of fluorescein indicated increased permeability at the higher MI. No bleeding was detected in any case.
The permeability change induced by insonation and this dose of an ultrasound contrast agent appears to be transient under the conditions studied, although the time delay between insonation and optical assessment limits the completeness of the findings. This preliminary study may be relevant to drug delivery strategies using ultrasound and microbubbles.
本研究旨在探究超声与血管内微泡造影剂联合使用在兔眼中引起的血管通透性变化的存在情况及持续时间。
对8只麻醉兔的5只眼睛进行研究。在给予全氟丙烷微泡（0.07 mL/kg）后，使用诊断B型系统（中心频率 = 2 MHz；机械指数[MI] = 0.2和1.7）进行5分钟的超声照射。在超声照射前和照射后3分钟进行荧光素眼底血管造影；在6分钟时，使用彩色眼底摄影评估染料渗漏、出血以及眼底血管直径的变化。
在低MI时，5只眼中有1只观察到眼底血管直径改变；在高MI时，5只眼中有4只观察到眼底血管直径改变。在1例中，荧光素渗漏表明在高MI时通透性增加。在任何情况下均未检测到出血。
在所研究的条件下，超声照射和该剂量的超声造影剂引起的通透性变化似乎是短暂的，尽管超声照射与光学评估之间的时间延迟限制了研究结果的完整性。这项初步研究可能与使用超声和微泡的药物递送策略相关。
