Publication

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

Journal Paper/Review - Feb 19, 2016

Units
PubMed
Doi

Citation
Bucher A, Kerl M, Albrecht M, Beeres M, Ackermann H, Wichmann J, Vogl T, Bauer R, Lehnert T. Systematic Comparison of Reduced Tube Current Protocols for High-pitch and Standard-pitch Pulmonary CT Angiography in a Large Single-center Population. Acad Radiol 2016; 23:619-27.
Type
Journal Paper/Review (English)
Journal
Acad Radiol 2016; 23
Publication Date
Feb 19, 2016
Issn Electronic
1878-4046
Pages
619-27
Brief description/objective

RATIONALE AND OBJECTIVES
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) 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.

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; 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).

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.