Evaluation of a Reconstruction Algorithm in Clinically Low-Dose Computed Tomography: Comparison of Phantom Images at various Contrast Media Concentrations Jung Kang-Kyo1, Cho Pyong-Kon1, Jang Hyon-Chul2 1Department of Radiological Science, Daegu Catholic University, Hayang-ro 13–13, Hayang-Eup, Gyeongsan-si, Gyeongbuk 2Department of Radiological Technology, Suseong College, Dalgubeol-Ro 528 gil 15, Suseong-Gu, Daegu, South Korea Online published on 14 May, 2018. Abstract To evaluate the feasibility of using clinically low-dose computed tomography (CT) with an iterative reconstruction (IR) algorithm in CT angiography (CTA) with various contrast media (CM) concentrations. We performed a phantom study using 128-channel MDCT with 270, 300, and 350 mg iodine/ml, first at 120 kV tube voltage combined with a conventional algorithm (standard protocol), and then at clinically low dose (80 kV), combined with conventional (filtered back-projection; FBP) and IR (ASIR-V) algorithms. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the tube centre and background were measured and the clinical radiation dose (CTDIVoL) determined. In all phantom studies, the higher the CM concentration was, the higher was the CT value. At all concentrations of iodine CM, clinically low-dose radiation with an IR algorithm significantly increased the SNR and CNR of the phantom study (P <.001). Compared to the standard protocol using a CM of 350 mg iodine/ml, the low-tube voltage with an IR algorithm using a CM of 300 mg iodine/ml significantly increased the SNR (43 ± 7 vs. 82 ± 22, respectively; P <. 001) and CNR (32 ± 7 vs. 70 ± 21, respectively; P <.001). The radiation dose (CTDIVoL) with the low-tube voltage and IR algorithm was 32% lower than that with the low-tube voltage with FBP algorithm, and 65% lower than the standard protocol (P <.001). Low CM concentrations improve images. Clinically low-dose CT with an IR algorithm is superior to the conventional protocol in phantom image contrast and exposure dose and is feasible for CTA. Top Keywords Clinically low-dose, Image contrast, Iterative reconstruction algorithm, Phantom, Contrast media. Top |