Department of Bioimaging and Radiological Sciences, Institute of Radiology, A. Gemelli Hospital-Catholic University, L.go A Gemelli 8, 00168 Rome, Italy.
Radiology. 2012 Apr;263(1):287-98. doi: 10.1148/radiol.11110700. Epub 2012 Feb 13.
To investigate the ionizing radiation dose, image quality, and diagnostic performance of computed tomographic (CT) angiography of the peripheral arteries with three different CT angiographic acquisition protocols, with use of pretreatment digital subtraction angiography (DSA) as the reference standard.
The study was approved by the institutional review board and performed in agreement with the 1990 Declaration of Helsinki and subsequent amendments. Each patient provided informed consent before undergoing CT. The authors performed a prospective, single-center, randomized comparison of three different x-ray exposure CT acquisition protocols in 60 randomized patients with peripheral arterial occlusive disease referred for 64-section multidetector CT angiography of the lower limb (0.625-mm collimation, intravenous administration of 100 mL of iomeprol [400 mg iodine per milliliter] at 4 mL/sec). The acquisition protocols were performed with (a) 120 kVp and a noise index of 26 (moderate noise reduction [MNR]), referred to as the 120-kVp MNR group; (b) 80 kVp and a noise index of 26, referred to as the 80-kVp MNR group; and (c) 80 kVp and a noise index of 30 (high noise reduction [HNR]), referred to as the 80-kVp HNR group. Axial and three-dimensional (3D) images were qualitatively and quantitatively compared by using the overall F test and pairwise comparisons. The X(2) test was used to compare the three protocols in terms of diagnostic performance in patients who also underwent DSA before an interventional procedure.
Significantly higher attenuation values were obtained in the vessels with the 80-kVp MNR and 80-kVp HNR acquisition protocols. No significant differences were noted in terms of image quality with either axial source images or 3D reconstructions. Likewise, no significant differences were found among the three protocols in terms of noise throughout the peripheral vasculature. Finally, no significant differences were found among the three groups with regard to diagnostic performance. Overall dose reductions of 48% and 61% were obtained for the 80-kVp MNR and 80-kVp HNR protocols, respectively.
Substantial reductions of radiation dose are achievable at multidetector CT angiography of the peripheral arteries without compromising image quality and diagnostic performance if acquisition protocols are modified appropriately and used in conjunction with a contrast material containing a high concentration of iodine.
以预处理数字减影血管造影（DSA）为参考标准，研究三种不同 CT 血管造影采集方案在周围动脉 CT 血管造影中的电离辐射剂量、图像质量和诊断性能。
本研究经机构审查委员会批准，并符合 1990 年赫尔辛基宣言及后续修正案的规定。每位患者在接受 CT 检查前均签署了知情同意书。作者对 60 例因下肢 64 层多层螺旋 CT 血管造影而转诊的周围动脉闭塞性疾病患者进行了前瞻性、单中心、随机对照研究，分别采用三种不同的 X 射线曝光 CT 采集方案（0.625mm 准直器，4ml/sec 静脉注射碘普罗胺[400mg 碘/毫升]100ml）。采集方案为：（a）120kVp，噪声指数 26（中度降噪[MNR]），称为 120kVp MNR 组；（b）80kVp，噪声指数 26，称为 80kVp MNR 组；（c）80kVp，噪声指数 30（高降噪[HNR]），称为 80kVp HNR 组。采用整体 F 检验和两两比较对轴向和三维（3D）图像进行定性和定量比较。采用 X（2）检验比较三种方案在介入治疗前也接受 DSA 的患者中的诊断性能。
在 80kVp MNR 和 80kVp HNR 采集方案中，血管的衰减值明显更高。轴向源图像和 3D 重建的图像质量无显著差异。同样，在整个外周血管中，三种方案的噪声也无显著差异。最后，三组之间的诊断性能也无显著差异。80kVp MNR 和 80kVp HNR 方案的总体剂量分别降低了 48%和 61%。
如果适当修改采集方案并与高浓度碘对比剂联合使用，则可在不影响图像质量和诊断性能的情况下，在外周动脉多层螺旋 CT 血管造影中实现辐射剂量的大幅降低。
