An instrument that in a painless and noninvasive manner uses the differential transmission and reflection of ultrasonic waves to create a detailed visual image of the brain.
超声波心动描记器一种用来显示详细的大脑图象的仪器,利用超声波发送和反射的差异来测试并无伤无痛
painless详细解释
pain.less
adj.(形容词) Free from complication or pain: 无痛的,无并发症的: 例句: a painless operation. 无痛的手术