Feasibility and optimization of aortic valve planimetry with MDCT
Feasibility and optimization of aortic valve planimetry with MDCT
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DOI：
10.2214/ajr.06.0232
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发表时间：
2007-02-01
影响因子：
5
通讯作者：
Brady, Thomas J.
中科院分区：
文献类型：
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作者：
Abbara, Suhny;Pena, Antonio J.;Brady, Thomas J.
OBJECTIVE.主动脉瓣可以使用MDCT进行评估;但是，主动脉开口面积的测量值会随着心动周期的变化而变化。在这项研究中，我们试图评估的最佳时机测量面积的主动脉开口MDCT。材料和方法。对57名患者进行了后向门控MDCT，参数如下：机架旋转时间，420毫秒;管电压，120 kV;管电流，550 mAs（管电流调制）;层厚，16 x 0.75 mm。以4 - 5 mL/s的速度静脉注射72 - 100 mL造影剂（320 g/mL（3））。在R波峰值后0、50、100、150和200毫秒的相位开始时获得高分辨率数据集进行面积测量，并评估主动脉开口面积和伪影的存在。在41%的患者中，具有最大主动脉开口面积的心脏相位在R波峰值后50毫秒。在R峰后0毫秒测量的主动脉开口面积为2.7 +/- 0.8 cm（2）（平均值+/- SD）; 50毫秒时，2.9 +/- 0.2 cm（2）; 100毫秒时，2.9 +/- 0.7 cm（2）; 150毫秒时，2.8 +/- 0.7 cm（2）;在200毫秒时为2.4 +/- 0.8 cm（2）。42%的患者在R峰后50毫秒时图像质量最好，29%的患者在100毫秒时图像质量最好，20%的患者在150毫秒时图像质量最好，7%的患者在0毫秒时图像质量最好，2%的患者在200毫秒时图像质量最好。3名患者的主动脉瓣在0毫秒时关闭，4名患者在200毫秒时关闭。在收缩中期存在较少的伪影（即，50 - 150毫秒）（“双叶”伪影，5 - 13%;“不完全轮廓”伪影，20 - 26%）比早期（0毫秒）和晚期（200毫秒）收缩期（双叶伪影，38%和43%的患者;不完全轮廓伪影，76%和73%的患者）。主动脉瓣面积测量最好在R峰后50 - 100毫秒的相位开始时进行，因为主动脉开口的面积最宽，并且该相位的图像质量最好。
OBJECTIVE. The aortic valve can be assessed using MDCT; however, measurements of the aortic opening area vary with the cardiac cycle. In this study, we sought to assess the optimal timing for measuring the area of the aortic opening with MDCT.MATERIALS AND METHODS. Retrospectively gated MDCT was performed in 57 patients with the following parameters: gantry rotation time, 420 milliseconds; tube voltage, 120 kV; tube current, 550 mAs with tube current modulation; and slice collimation, 16 x 0.75 mm. From 72 to 100 mL of contrast agent ( 320 g/mL(3)) was injected IV at 4 - 5 mL/s. High-resolution data sets were obtained for planimetry at phase starts of 0, 50, 100, 150, and 200 milliseconds after the R wave peak and were assessed for aortic opening area and the presence of artifacts.RESULTS. In 41% of patients, the cardiac phase with the largest aortic opening area was at 50 milliseconds after the R wave peak. The area of the aortic opening measured at 0 milliseconds after the R peak was 2.7 +/- 0.8 cm(2) ( mean +/- SD); at 50 milliseconds, 2.9 +/- 0.2 cm(2); at 100 milliseconds, 2.9 +/- 0.7 cm(2); at 150 milliseconds, 2.8 +/- 0.7 cm(2); and at 200 milliseconds, 2.4 +/- 0.8 cm(2). The image quality was best at 50 milliseconds after the R peak in 42% of patients, 100 milliseconds in 29%, 150 milliseconds in 20%, 0 milliseconds in 7%, and 200 milliseconds in 2%. The aortic valve appeared closed in three patients at 0 milliseconds and in four patients at 200 milliseconds. Fewer artifacts were present in the midsystolic phases (i.e., 50 - 150 milliseconds) ("double-leaflet" artifact, 5 - 13%; "incomplete contour" artifact, 20 - 26%) than in the early ( 0 milliseconds) and late ( 200 milliseconds) systolic phases (double-leaflet artifact, 38% and 43% of patients; incomplete contour artifact, 76% and 73%, respectively).CONCLUSION. Aortic valve planimetry is best performed at phase starts of 50 - 100 milliseconds after the R peak because the area of the aortic opening is widest and image quality is best at that phase.