Systematic Comparison of Reduced Tube Current Protocols for High-pitch and Standard-pitch Pulmonary CT Angiography in a Large Single-center Population

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• 作者：Andreas M. Bucher ; MD ; ^{Doktorb@gmx.ch" class="auth_mail" title="E-mail the corresponding author} ; Matthias J. Kerl ; MD ; Moritz H. Albrecht ; MD ; Martin Beeres ; MD ; Hanns Ackermann ; PhD ; Julian L. Wichmann ; MD ; Thomas J. Vogl ; MD ; Ralf W. Bauer ; MD ; T. Lehnert ; MD
• 关键词：Pulmonary CT angiography ; reduced tube current protocol ; high-pitch CT acquisition
• 刊名：Academic Radiology
• 出版年：2016
• 出版时间：May 2016
• 年：2016
• 卷：23
• 期：5
• 页码：619-627
• 全文大小：472 K

文摘

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.

Materials and Methods

Three hundred eighty-two consecutive patients (October 2010 through December 2012) received clinically indicated CTPA with one of four consecutively changed protocols: (1) HP_SC: 180 mAs, weighted filtered back projection, pitch = 3; (2) HP_RC: 90 mAs, IR, pitch = 3; (3) SP_SC: 180 mAs, weighted filtered back projection, pitch = 1.2; and (4) HP_RC: 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 (sSNR_PT) and on segmental artery level (sSNR_S1, sSNR_S10). 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.

Results

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; SP_SC: 139.5 mGycm; HP_RC: 92 mGycm; SP_SC: 211 mGycm; HP_RC: 137 mGycm). sSNR was comparable (sSNR_PT overall: P = 0.052; sSNR_S1 overall: P = 0.161; and sSNR_S10 overall: P = 0.259).

Conclusions

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.