Phantom study on effect of advanced modeled iterative reconstruction on image quality and radiation dose

OBJECTIVE: The purpose of the current study was to evaluate the effect of an iterative reconstruction algorithm named advanced modeled iterative reconstruction (ADMIRE) on improving image quality and reducing the radiation dose. MATERIALS AND METHODS: The Catphan phantom (Phantom Lab, USA) was scanned on a SOMATOM Force CT scanner (Siemens Healthcare, Forchheim, Germany) with different exposure parameters. Phantom images, reconstructed using filtered back projection (FBP) and ADMIRE with iterative strength of 1~5, were compared with respect to noise, Contrast-to-Noise Ratio (CNR) and modulation transfer function (MTF). Result: Image noise decreased as iterative strength increased, while CNR went up as iterative strength rose. Compared to FBP, the noise reduction and CNR increase for iterative strength 3 were found to be25.01%~33.29% and 24.45%~53.31%, respectively. And for iterative strength 5, the noise reduction and CNR increase were found to be 45.43%~56.66% and 80.43%~135.45%, respectively. There was almost no change in the values of MTF between the images reconstructed using FBP and ADMIRE with iterative strengths of 1~5. The radiation dose was reduced about 46%~53%, 49%~63% and 65%~69% for ADMIRE with iterative strength of 3, 4 and 5, respectively. And there was no significant difference in image noise and CNR of scans with the reduced dose and the original dose CT (P>0.05). Conclusion: ADMIRE shows good potential in reducing image noise and improving CNR without affecting sharpness of the image. By applying this approach, radiation dose will be decreased for the patients without degrading the image quality.