Image Quality and Dose Reduction by Dual Source Computed Tomography Coronary Angiography: Protocol Comparison

Abstract

Purpose:To compare image quality and radiation dose among different protocols in patients who underwent a 128-slice dual source computed tomography coronary angiography (DSCT-CTCA).Methods:Ninety patients were retrospectively grouped according to heart rate (HR): 26 patients (group A) with stable HR ≤60 bpm were acquired using high pitch spiral mode (FLASH); 48 patients (group B) with irregular HR ≤60 bpm or stable HR between 60 and 70 bpm using step and shoot mode; and 16 patients (group C) with irregular HR >60 bpm or stable HR ≥70 bpm by retrospective electrocardiogram pulsing acquisition. Signal to noise ratio (SNR) and contrast to noise ratio (CNR) were measured for the main vascular structures. Moreover, the dose-length product and the effective dose were assessed.Results:Both SNR and CNR were higher in group A compared to group C (18.27 ± 0.32 vs 11.22 ± 0.50 and 16.75 ± 0.32 vs 10.17 ± 0.50; P = .001). The effective dose was lower in groups A and B (2.09 ± 1.27 mSv and 4.60 ± 2.78 mSv, respectively) compared to group C (9.61 ± 5.95 mSv) P < .0001.Conclusion:The correct selection of a low-dose, HR-matched CTCA scan protocol with a DSCT scanner provides substantial reduction of radiation exposure and better SNR and CNR.

Radiation Dose and Image Quality of a High-Pitch Prospective Spiral First Approach in Coronary Computed Tomography Angiography (CCTA)

“…Concerns on the robustness of HPSF imaging can be mitigated by our finding that the image quality of this approach is comparable to conventional scan regimes, in-line with results from other working groups that validated the image quality of high-pitch spiral scans [ 14 , 21 , 22 , 23 ]. Indeed, the diagnostic yield of CCTAs in the HPSF approach was comparable to a NHPSF approach, allowing 1399 of 1410 patients to benefit from a non-invasive, low-radiation coronary imaging with comparable negative predictive value to invasive coronary angiography [ 24 , 25 ].…”

Whole Body Low Dose Computed Tomography Using Third-Generation Dual-Source Multidetector With Spectral Shaping: Protocol Optimization and Literature Review

“… 4 Most recent studies, instead, employes a 120 kV protocol and a tube current between 30 and 100 mAs, to achieve an effective dose ranging between 2.7 mSv 9 and 29,5 mSv. 4 , 6 - 10 , 12 - 18 , 21 - 23 , 25 - 32 Other studies have been focused on a different approach based on low tube voltage (80 kV) and high current (200–230 mAs), generating an effective dose of about 4.5 mSv. 14 …”

“…13 Multiple studies have been performed in order to optimize the protocol and provide a lower effective dose than the CSS. 9,10,13,22,[25][26][27][28] Several works tested different combinations of CT parameters in order to obtain a reliable and diagnostic protocol. Gleeson et al tested combinations of kV that range from 80-140 kVp, and tube current-time product from 14-125 mAs with the modulation of the activated current and a moderately sharp reconstruction algorithm, to generate a low effective dose of about 1.74 mSv, 29 while Kropil et al used a 100 kV and 100 mAs protocol, with automatic tube current modulation, to administer an effective dose of approximately 4.8 mSv.…”

“…4 Most recent studies, instead, employes a 120 kV protocol and a tube current between 30 and 100 mAs, to achieve an effective dose ranging between 2.7 mSv 9 and 29,5 mSv. 4,[6][7][8][9][10][12][13][14][15][16][17][18][21][22][23][25][26][27][28][29][30][31][32] Other studies have been focused on a different approach based on low tube voltage (80 kV) and high current (200-230 mAs), generating an effective dose of about 4.5 mSv. 14 Saravanabavaan et al exploited the potential of spectral shaping thanks to tin filter, in synergy with IR and automatic current modulation on a third-generation DSCT (Sn 100 kV, ref.…”

“…A 4-point scale was used (1 excellent = absence of artifacts; 2 good = minimal artifacts, mild blurring or structure discontinuity but fully evaluable; 3 suboptimal = moderate artifacts and blurring or structure discontinuity; 4 not diagnostic = doubling or discontinuity in the course of the segment preventing diagnostic evaluation. 25 In case of disagreement between the observers, consensus was reached in a joint reading to determine the final image quality score. A per-patient image quality score was defined as the worst score found in any region for each patient.…”