[问答题,简答题] 简述血小板输注的适应症。

输血反应有哪些? 与平片相比，下列哪项不是CT优势() ["A．横断面成像","B．解剖分辨率高","C．密度分辨率高","D．空间分辨率高","E．增强扫描，有利于病变定性"] 软组织损伤的体征可有() ["A．压痛","B．肿胀","C．发绀","D．抽屉试验阳性","E．直腿抬高试验阳性"] 输注血浆有些什么副作用? 交叉韧带损伤可有() ["A．膝关节不稳定","B．膝关节肿胀","C．抽屉试验阳性","D．关节活动受限","E．回旋挤压试验阳性"] 简述血小板输注的适应症。