目的探讨自制纳米超声对比剂的体外物理特征及其在裸鼠体内的显影效果。方法应用机械振动法制备,检测纳米微泡的形态、散布、粒径范围以及浓度,采用自身前后对照的统计学方法观察两种对比剂在裸鼠体内的成像特征以及定量结果的差异性。结果镜下纳米微泡接近圆形,大小、分布较统一,离散度较好。纳米微泡的粒径范围在418~490 nm之间,平均粒径(463.2±27.69)nm(n=5),表面电荷-14.8 m V,浓度约2.3×108/ml,4℃冰箱中保存1周后,性质稳定,平均粒径(525.80±18.08)nm(n=5),较1周前对比无统计学差异(P>0.05)。纳米级对比剂能明显增强瘤体的灰阶显像,对比剂到达时间[(0.90±0.42)s]和达峰时间[(24.01±5.83)s]较Sonovue对比剂[(0.35±0.15)s、(2.91±0.93)s]晚,峰值持续时间[(111.65±20.87)s、(58.59±10.49)s]较长,但峰值强度[(14.18±3.45)d B、(19.36±3.72)d B]较弱,两者比较差异均有统计学意义(均P<0.05)。结论纳米级对比剂粒径小、稳定性高,在裸鼠体内有明显的增强显像效果,可以初步满足临床应用的要求。 Objective To investigate the in vitro physical characteristics of self-made nano-contrast media and its imaging effect in nude mice. Methods The morphology, distribution, size range and concentration of nano-microbubbles were detected by mechanical vibration method. The imaging characteristics and quantitative results of two contrast media in nude mice were observed by their own statistical methods. Results Microscopically, the microspheres were nearly circular in shape, with a uniform distribution and good dispersion. The size of nanometer microbubbles ranged from 418 to 490 nm with an average particle size of 463.2 ± 27.69 nm (n = 5), a surface charge of -14.8 mV and a concentration of 2.3 × 108 / ml. After 1 week, the cells were stable in nature with an average diameter of 525.80 ± 18.08 nm (n = 5), showing no significant difference compared with that of the previous one week (P> 0.05). Compared with Sonovue contrast agent [(0.35 ± 0.15) s], the contrast agent arrival time [(0.90 ± 0.42) s] and peak time [(24.01 ± 5.83) s] , (2.91 ± 0.93) s], the peak duration [(111.65 ± 20.87) s, (58.59 ± 10.49) s] was longer, but the peak intensity [(14.18 ± 3.45) d B, (19.36 ± 3.72) d B ] Were weaker, the difference between the two was statistically significant (P <0.05). Conclusion Nanometer-sized contrast agent has the advantages of small particle size and high stability. It can obviously enhance the imaging effect in nude mice, which can initially meet the requirements of clinical application.