Duvernoy O, Coulden R, Ytterberg C
Department of Diagnostic Radiology, University Hospital, Uppsala, Sweden.
J Comput Assist Tomogr. 1995 Jul-Aug;19(4):569-72.
Artefacts complicate the diagnosis of thoracic aortic dissection by CT. Aortic compliance and cardiac motion may be responsible but the precise cause of these artefacts remains unclear.
Fifty consecutive clinical thoracic CT examinations performed on a Siemens Somatom Plus scanner (8 mm slice thickness, 1 s scan time) were reviewed (mean patient age 56 years). For each examination, the presence, position, and displacement of motion artefact from the aortic wall were noted at three ascending aortic levels. Cine ultrafast CT on 10 volunteers (mean age 49 years) was used to assess aortic motion for the same three levels (8 mm slice thickness, 50 ms scan time). Digital subtraction of consecutive cine CT allowed the position of the aortic wall throughout the cardiac cycle to be tracked.
Curvilinear motion artefacts were seen in the ascending aorta in 17 conventional CT scans, occurring left anterior and right posterior in all but one and maximally at the aortic root (mean amplitude 3.5 mm). Ultrafast CT, however, showed no motion artefact and no significant change in aortic area with systole. Aortic motion in the sagittal-oblique plane at the ascending aorta was confirmed.
Motion artefacts simulating ascending aortic dissection occur frequently on conventional CT. Their position is predictable and is related to systolic aortic motion from the left anterior to the right posterior position.
伪影使CT诊断胸主动脉夹层变得复杂。主动脉顺应性和心脏运动可能是其原因，但这些伪影的确切病因仍不清楚。
回顾了在西门子Somatom Plus扫描仪上进行的50例连续临床胸部CT检查（层厚8mm，扫描时间1s）（患者平均年龄56岁）。对于每次检查，在升主动脉的三个水平记录主动脉壁运动伪影的存在、位置和移位情况。对10名志愿者（平均年龄49岁）进行超快速CT电影扫描，以评估相同三个水平的主动脉运动（层厚8mm，扫描时间50ms）。连续CT电影扫描的数字减法可追踪心动周期中主动脉壁的位置。
在17例传统CT扫描中，升主动脉可见曲线形运动伪影，除1例外在所有扫描中均出现在左前和右后，且在主动脉根部最为明显（平均幅度3.5mm）。然而，超快速CT未显示运动伪影，且收缩期主动脉面积无显著变化。证实了升主动脉矢状斜面上的主动脉运动。
传统CT上经常出现模拟升主动脉夹层的运动伪影。其位置可预测，且与收缩期主动脉从左前到右后的运动有关。
