升主动脉夹层样搏动伪影的多层螺旋CT表现

Multi-slice spiral CT findings of motion artifact simulating ascending aortic dissection

目的 探讨多层螺旋CT上升主动脉夹层样搏动伪影的发生率及其表现.方法 93例患者作了胸部CT检查,男54例,女39例;年龄15～94岁,平均年龄（49.6±15.7）岁.观察CT图像,判断有无主动脉搏动伪影、发生部位、宽度、长度、边界是否清楚及伪影的连续性.结果 93例患者中,72例出现升主动脉搏动伪影,检出率为77.4%,都累及升主动脉,搏动伪影最常发生在左前壁（70.8%）和右后壁（34.7%）.伪影的宽度为2.3～8.6 mm,平均为（5.4±1.9）mm,长度为1～7层,平均为（2.8±1.3）层.64例（88.9%）伪影形成的＂假腔＂或＂内膜片＂在平扫CT上清晰可见其边界.伪影在上下层面出现间断16例（22.2%）,伪影发生部位有变化共28例（38.9%）,在增强CT图像上伪影消失5例（14.7%）,增强CT发生部位改变15例（44.1%）.结论 主动脉夹层样搏动伪影在多层螺旋CT上发生率较高,多发生于主动脉弓的左前方和右后方,长度及宽度范围局限、边界清楚及缺乏连续性,根据上述CT表现可对伪影做出鉴别诊断.

Objective To evaluate the prevalence and findings of motion artifact simulating ascending aortic dissection on multi-slice spiral CT. Methods We reviewed 93 subjects （54 men and 39 women） who had undergone chest CT. The mean age of patients was （49.6±15.7） years （range, 15-94 years）. Two investigators evaluated the CT images regarding the presence, locations, width, length, margin and continuity of motion artifact. Results Of the 93 scans, 72（77.4% ） had aortic motion artifacts. Of the 72 motion artifacts, all affected the ascending aorta, 51（70.8%） and 25（34.7%） involved the left anterior and right posterior aspects of the aortic circumference respectively. The width of motion artifact was （5.4 ± 1.9） mm （range, 2.3-8.6 mm）, the length was （2.8±1.3） slices （range, 1-7 slices）. 64（88.9%） motion artifacts had clear margin on the plain CT images. Continuity of motion artifacts was recorded. 16（22.2%） was lack of continuity on the next image, and the location was changed in 28 cases（38.9 %）. Five artifacts disappeared on enhancement CT, and the location was changed in 15 cases （44.1%）. Conclusion Motion artifacts of ascending aortic are frequently seen on thoracic CT. Most of the artifacts affected the left anterior and right posterior aspects of the aortic circumference. The features of motion artifacts include the limited extent, the clear margin and the absence of continuity. These features are helpful for distinguishing artifacts from dissection.