Computed Tomography Angiography with a 192-slice Dual-source Computed Tomography System: Improvements in Image Quality and Radiation Dose.
OBJECTIVE
This study aims to compare image quality, radiation dose, and the influence of the heart rate on image quality of high-pitch spiral coronary computed tomography angiography (CCTA) using 128-slice (second generation) dual-source CT (DSCT) and a 192-slice DSCT (third generation) scanner.


METHODS
Two consecutive cohorts of fifty patients underwent CCTA by high-pitch spiral scan mode using 128 or 192-slice DSCT. The 192-slice DSCT system has a more powerful roentgen tube (2 × 120 kW) that allows CCTA acquisition at lower tube voltages, wider longitudinal coverage for faster table speed (732 m/s), and the use of iterative reconstruction. Objective image quality was measured as the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Subjective image quality was evaluated using a Likert scale.


RESULTS
While the effective dose was lower with 192-slice DSCT (1.2 ± 0.5 vs. 0.6 ± 0.3 mSv;P< 0.001), the SNR (18.9 ± 4.3 vs. 11.0 ± 2.9;P< 0.001) and CNR (23.5 ± 4.8 vs. 14.3 ± 4.1;P< 0.001) were superior to 128-slice DSCT. Although patients scanned with 192-slice DSCT had a faster heart rate (59 ± 7 vs. 56 ± 6;P= 0.045), subjective image quality was scored higher (4.2 ± 0.8 vs. 3.0 ± 0.7;P< 0.001) compared to 128-slice DSCT.


CONCLUSIONS
High-pitch spiral CCTA by 192-slice DSCT provides better image quality, despite a higher average heart rate, at lower radiation doses compared to 128-slice DSCT.
Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Philip V M
PV
Linsen
Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Adriaan
A
Coenen
Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Marisa M
MM
Lubbers
Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Marcel L
ML
Dijkshoorn
Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Mohamed
M
Ouhlous
Department of Radiology, Erasmus Medical Center, Rotterdam, The Netherlands; Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.
Koen
K
Nieman
Computed tomography; coronary angiography; heart rate; image quality; radiation dose