Upgrade to Iterative Image Reconstruction (IR) in Abdominal MDCT Imaging: A Clinical Study for Detailed Parameter Optimization Beyond Vendor Recommendations Using the Adaptive Statistical Iterative Reconstruction Environment (ASIR)

作者：Mueck F G^*; Koerner M; Scherr M K; Geyer L L; Deak Z; Linsenmaier U; Reiser M; Wirth S

来源：RoFo-Fortschritte auf dem Gebiet der Rontgenstrahlen und der Bildgebenden Verfahren, 2012, 184(3): 229-238.

DOI：10.1055/s-0031-1282032

• abdomen
• iterative reconstruction
• dose reduction
• ASIR
• computed tomography

Purpose: To compare the image quality of dose-reduced 64-row abdominal CT reconstructed at different levels of adaptive statistical iterative reconstruction (ASIR) to full-dose baseline examinations reconstructed with filtered back-projection (FBP) in a clinical setting and upgrade situation.
Materials and Methods: Abdominal baseline examinations (noise index NI = 29; LightSpeed VCT XT, GE) were intra-individually compared to follow-up studies on a CT with an ASIR option (NI = 43; Discovery HD750, GE), n = 42. Standard-kernel images were calculated with ASIR blendings of 0 - 100 % in slice and volume mode, respectively. Three experienced radiologists compared the image quality of these 567 sets to their corresponding full-dose baseline examination (- 2: diagnostically inferior, - 1: inferior, 0: equal, +1: superior, +2: diagnostically superior). Furthermore, a phantom was scanned. Statistical analysis used the Wilcoxon - the Mann-Whitney U-test and the intra-class correlation (ICC).
Results: The mean CTDIvol decreased from 19.7 +/- 5.5 to 12.2 +/- 4.7 mGy (p < 0.001). The ICC was 0.861. The total image quality of the dose-reduced ASIR studies was comparable to the baseline at ASIR 50% in slice (p = 0.18) and ASIR 50 - 100% in volume mode (p > 0.10). Volume mode performed 73% slower than slice mode (p < 0.01).
Conclusion: After the system upgrade, the vendor recommendation of ASIR 50% in slice mode allowed for a dose reduction of 38% in abdominal CT with comparable image quality and time expenditure. However, there is still further dose reduction potential for more complex reconstruction settings.

• 出版日期2012-3