对慢性血栓描述不正确的是 ["边界不规则的斑块强回声 ","与静脉壁混为一体的机化血栓 ","血栓处管腔增宽，但程度不同 ","静脉瓣膜厚而扭曲，活动硬而固定 ","再通局部充满血流信号"] 有关四肢静脉血栓描述错误的是 ["急性血栓指几小时至几天内的血栓 ","慢性血栓多指数月至数年的血栓 ","亚急性血栓指数周以后的血栓 ","急性血栓多呈强回声 ","血栓局部管腔不能被压瘪"] PTV英文缩写的中文意思是 ["大隐静脉 ","股总静脉 ","股浅静脉 ","股深静脉 ","胫后静脉"] 描述正常四肢静脉二维超声表现的是 ["壁薄，不易显示，内膜光滑 ","管腔内呈无回声，或显示流动的红细胞 ","内径大于伴行动脉的内径 ","乏氏动作时，内径增宽 ","以上都是"] 探测下肢静脉的最佳体位是 ["头高脚低位 ","仰卧位 ","站立位 ","半坐位 ","侧卧位"] 正常肢体静脉CDFI的正确描述是