Influence of different movement systems on image quality: comparison of the sliding gantry CT system and the sliding table CT system

The combination of angiography and CT angiography (CTA) is increasingly being used for the diagnosis and treatment of hepatic cancer. Recently, a CT system with sliding gantry was developed to optimize patient safety and to shorten transfer time between the angiography and CTA tables. As the CT gantry itself undergoes considerable movement in sliding over the patient table, it was considered necessary to evaluate this system regarding the precision of movement and any possible effect on image quality. Therefore, in this preliminary study, we compared image quality between the sliding gantry CT (SGCT) system and the sliding table CT (STCT) system. Comparative analysis revealed that there was no significant difference in image noise, low contrast resolution, modulation transfer function (MTF) , or precision in gantry or table movement. It was also noted that although the effective slice thickness for the SGCT system was 1-4% thinner than the STCT system it had no influence on image quality. It was thus concluded that the sliding movement of the gantry does not influence the quality of images obtained with this CT system.