Bucher Andreas M, Kerl Matthias J, Albrecht Moritz H, Beeres Martin, Ackermann Hanns, Wichmann Julian L, Vogl Thomas J, Bauer Ralf W, Lehnert T
Institute for Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, House 23c, 60590 Frankfurt, Germany.
Institute for Diagnostic and Interventional Radiology, Theodor-Stern-Kai 7, House 23c, 60590 Frankfurt, Germany.
Acad Radiol. 2016 May;23(5):619-27. doi: 10.1016/j.acra.2016.01.003. Epub 2016 Feb 19.
Benefits of iterative reconstruction (IR) algorithms combined with dose-reduction techniques have been shown at computed tomography pulmonary angiography (CTPA) in several medium to small patient collectives. In this study, we performed a systematic comparison of image quality to combinations of reduced tube current (RC) and IR for both standard-pitch (SP) single-source and high-pitch (HP) dual-source CTPA in a large, single-center population.
Three hundred eighty-two consecutive patients (October 2010 through December 2012) received clinically indicated CTPA with one of four consecutively changed protocols: (1) HPSC: 180 mAs, weighted filtered back projection, pitch = 3; (2) HPRC: 90 mAs, IR, pitch = 3; (3) SPSC: 180 mAs, weighted filtered back projection, pitch = 1.2; and (4) HPRC: 90 mAs, IR, pitch = 1.2. Tube potential was 100 kV. Vascular attenuation and standardized signal-to-noise ratio (sSNR) were measured in the pulmonary trunk (sSNRPT) and on segmental artery level (sSNRS1, sSNRS10). Dose-length-product was recorded per series. Two independent investigators rated image quality. Kolmogorov-Smirnov test, Kruskal-Wallis test, and kappa statistics were used for statistical analysis. Median values are presented per group.
Image quality was consistent between all groups (observer 1: P = 0.118; observer 2: P = 0.122). Inter-reader consistency was very good (κ = 0.866, P < 0.001). Dose-length-product was significantly reduced in HP and RC groups (P < 0.001 for each; SPSC: 139.5 mGycm; HPRC: 92 mGycm; SPSC: 211 mGycm; HPRC: 137 mGycm). sSNR was comparable (sSNRPT overall: P = 0.052; sSNRS1 overall: P = 0.161; and sSNRS10 overall: P = 0.259).
Substantial dose reduction can be within a routine clinical setting without quantifiable loss of image quality either by HP pulmonary angiography or by a combination of IR and RC in either HP or SP acquisition.
在多个中、小型患者群体的计算机断层扫描肺动脉造影（CTPA）中，已显示迭代重建（IR）算法与剂量降低技术相结合的益处。在本研究中，我们在一个大型单中心人群中，对标准螺距（SP）单源和高螺距（HP）双源CTPA的降低管电流（RC）与IR组合的图像质量进行了系统比较。
382例连续患者（2010年10月至2012年12月）接受了临床指征的CTPA检查，采用四种连续变化的方案之一：（1）HPSC：180 mAs，加权滤波反投影，螺距 = 3；（2）HPRC：90 mAs，IR，螺距 = 3；（3）SPSC：180 mAs，加权滤波反投影，螺距 = 1.2；（4）HPRC：90 mAs，IR，螺距 = 1.2。管电压为100 kV。在肺动脉主干（sSNRPT）和节段动脉水平（sSNRS1，sSNRS10）测量血管衰减和标准化信噪比（sSNR）。记录每个系列的剂量长度乘积。两名独立的研究者对图像质量进行评分。采用Kolmogorov-Smirnov检验、Kruskal-Wallis检验和kappa统计进行统计分析。每组给出中位数。
所有组之间的图像质量一致（观察者1：P = 0.118；观察者2：P = 0.122）。阅片者间一致性非常好（κ = 0.866，P < 0.001）。HP和RC组的剂量长度乘积显著降低（每组P < 0.001；SPSC：139.5 mGycm；HPRC：92 mGycm；SPSC：211 mGycm；HPRC：137 mGycm）。sSNR具有可比性（总体sSNRPT：P = 0.052；总体sSNRS1：P = 0.161；总体sSNRS10：P = 0.259）。
在常规临床环境中，通过HP肺动脉造影或HP或SP采集时IR与RC的组合，可实现大幅剂量降低，且图像质量无可量化损失。
