Pushing CT and MR Imaging to the Molecular Level for Studying the “Omics”: Current Challenges and Advancements

Figure 2

The schematic of four CT manufactures’ IR algorithms: Siemens’ Sinogram Affirmed Iterative Reconstruction (SAFIRE), Philips’ iDose⁴, Toshiba’s Adaptive Iterative Dose Reduction 3D (ADIR 3D), and GE’s Adaptive Statistical Iterative Reconstruction (ASIR). Both SAFIRE and iDose⁴ have a similar iterative correction process operating in the image domain. In the projection domain, SAFIRE performs a projection data correction via forward and backward (i.e., weighted FBP) projection; however, iDose⁴ directly corrects projection data. ADIR 3D performs a noniterative correction in the projection domain and an iterative correction in the image domain. Also, a weighted blending is applied to the input image (i.e., after projection data correction) and the output image (i.e., after iterative process). Unlike the other three IR algorithms, ASIR performs an iterative correction process by comparing synthesized projection data to measured projection data.