英语语法分析

On retrograde pyelography the catheter is curved as"S"shape.

逆行肾盂造影时输尿管导管弯曲，呈“S”形。

Intravenous pyelography played an important role in diagnosis of small ureter stone.

静脉肾孟造影对输尿管小结石有重要作用。

Objective:To investigate the application of computed radiography (CR) in intravenous pyelography.

目的：探讨CR在静脉肾盂造影中的应用。