Manning Brian J, Kristmundsson Thorarinn, Sonesson Björn, Resch Timothy
Vascular Centre Malmö-Lund, Malmö University Hospital, Malmö, Sweden.
J Vasc Surg. 2009 Aug;50(2):263-8. doi: 10.1016/j.jvs.2009.02.243.
Aortic aneurysm size is a critical determinant of the need for intervention, yet the maximal diameter will often vary depending on the modality and method of measurement. We aimed to define the relationship between commonly used computed tomography (CT) measurement techniques and those based on current reporting standards and to compare the values obtained with diameter measured using ultrasound (US).
CT scans from patients with US-detected aneurysms were analyzed using three-dimensional reconstruction software. Maximal aortic diameter was recorded in the anteroposterior (CT-AP) plane, along the maximal ellipse (CT-ME), perpendicular to the maximal ellipse (CT-PME), or perpendicular to the centerline of flow (CT-PCLF). Diameter measurements were compared with each other and with maximal AP diameter according to US (US-AP). Analysis was performed according to the principles of Bland and Altman. Results are expressed as mean +/- standard deviation.
CT and US scans from 109 patients (92 men, 17 women), with a mean age of 72 +/- 8 years, were included. The mean of each series of readings on CT was significantly larger than the mean US-AP measurement (P < .001), and they also differed significantly from each other (P < .001). The CT-PCLF diameter was larger than CT-AP and CT-PME by mean values of 3.0 +/- 6.6 and 5.9 +/- 6.0 mm, respectively. The CT-ME diameter was larger than CT-PCLF by a mean of 2.4 +/- 5 mm. The US-AP diameter was smaller than CT-AP diameter by 4.2 +/- 4.9 mm, CT-ME by 9.6 +/- 8.0 mm, CT-PME by 1.3 +/- 5 mm, and smaller than CT-PCLF by 7.3 +/- 7.0 mm. Aneurysm size did not significantly affect these differences. Seventy-eight percent of 120 pairs of intraobserver CT measurements and 65% of interobserver CT measurements differed by <2 mm.
CT-based measurements of aneurysm size tend to be larger than the US-AP measurement. CT-PCLF diameters are consistently larger than CT-PME as well as CT-AP measurements. These differences should be considered when applying evidence from previous trials to clinical decisions.
主动脉瘤大小是决定是否需要干预的关键因素，然而最大直径往往会因测量方式和方法的不同而有所变化。我们旨在明确常用的计算机断层扫描（CT）测量技术与基于当前报告标准的测量技术之间的关系，并比较CT测量值与超声（US）测量的直径值。
使用三维重建软件分析超声检测出动脉瘤患者的CT扫描图像。在前后位（CT-AP）平面、沿最大椭圆（CT-ME）、垂直于最大椭圆（CT-PME）或垂直于血流中心线（CT-PCLF）记录主动脉最大直径。将各直径测量值相互比较，并与超声测量的最大前后位直径（US-AP）进行比较。根据布兰德和奥特曼原理进行分析。结果以均值±标准差表示。
纳入了109例患者（92例男性，17例女性）的CT和超声扫描图像，平均年龄为72±8岁。CT上各系列读数的均值显著大于超声测量的US-AP均值（P <.001），且各测量值之间也存在显著差异（P <.001）。CT-PCLF直径分别比CT-AP和CT-PME直径均值大3.0±6.6 mm和5.9±6.0 mm。CT-ME直径比CT-PCLF直径均值大2.4±5 mm。US-AP直径比CT-AP直径小4.2±4.9 mm，比CT-ME小9.6±8.0 mm，比CT-PME小1.3±5 mm，比CT-PCLF小7.3±7.0 mm。动脉瘤大小对这些差异无显著影响。120组观察者内CT测量值中有78%、观察者间CT测量值中有65%的差异<2 mm。
基于CT的动脉瘤大小测量值往往大于超声测量的US-AP值。CT-PCLF直径始终大于CT-PME以及CT-AP测量值。在将以往试验的证据应用于临床决策时应考虑这些差异。
