digital subtraction的用法和样例：
例句
- Blood supply reestablishment of avascular necrosis of femoral head with digital subtraction angiography.
股骨头坏死血供重建的数字减影血管造影研究。 - Lacrimal drainage system imaging by the digital subtraction dacryocystography provided reliable and accurate demonstration of lacrimal duct obstruction.
数字减影泪道造影术能够提供清晰的泪道图像并对泪道阻塞的部位及泪道改变作出准确的判断。
