Dose reduction techniques in coronary calcium scoring: The effect of iterative reconstruction combined with low tube voltage on calcium scores in a thoracic phantom

作者：Vonder Marleen^*; Pelgrim Gert Jan; Meyer Mathias; Henzler Thomas; Oudkerk Matthijs; Vliegenthart Rozemarijn

来源：European Journal of Radiology, 2017, 93: 229-235.

DOI：10.1016/j.ejrad.2017.06.001

• Tomography
• X-Ray computed
• Coronary artery disease
• Coronary atherosclerosis
• Radiation Dosage
• Phantoms
• Imaging

Objectives: To define a dose-reduced coronary calcium CT protocol that provides similar calcium score values as a conventional 120 kVp protocol.
Methods: A thorax phantom containing 100 calcifications was scanned with the reference protocol (120 kVp, 90 ref mAs, FBP) and 30 dose-reduced protocols (70-110 kVp, 90 ref mAs, FBP and iterative reconstruction (IR) levels 1-5) with 3rd generation dual-source CT. For protocols that yielded similar detectability and calcium scores as the reference protocol, additional scans were acquired at reduced ref mAs. Kendall's tau b and independent-samples-median test were used to determine trends and differences in contrast/signal-to-noise ratio (CNR and SNR), dose and calcium scores.
Results: The detectability and calcium scores decreased at increasing IR levels (tau b < -0.825, p < 0.001) and increasing tube voltage (tau b < -0.679, p < 0.001). For 90 kVp-IR3 and 100 kVp-IR1, similar detectability and calcium score was found compared to the reference protocol (p > 0.206). For these protocols, lower tube currents did not affect the detectability and Agatston score (p > 0.206), while CNR and SNR were similar/higher compared to the reference protocol (0.008 < p < 0.206). Dose reduction was 60.6% (90 kVp-IR3) and 43.6% (100 kVp-IR1).
Conclusions: The protocol of 90 kVp-IR3 and 100 kVp-IR1 yielded similar calcium detectability, Agatston score and image quality as the reference protocol, with dose reduction up to 60.6%.

• 出版日期2017-8