低線量腹部CT 撮影におけるアーチファクト低減処理法を用いたダークバンドアーチファクト低減効果の検証

抄録

Purpose: The purpose of this study was to validate the reduction of dark band (DB) artifact using iterative reconstruction (IR) of abdomen CT. Methods: Phantoms were arranged with and without small phantom assuming arm position at the body side (Phantom-A, -B). Image reconstruction methods were derived by the following four methods: filtered back projection (FBP), IR [adaptive iterative dose reduction using three-dimensional processing: AIDR-3D (MILD)], organ specific reconstruction (OSR), and Boost-3D (Boost). We evaluated DB artifact with CT values, standard deviation (SD) values, and profile curves using the four reconstruction methods. Results: CT values of artifact decreased with low tube current in Phantom-A. CT values of artifact were significantly increased (15–23 HU) in OSR and Boost compared to FBP and MILD (Phantom-A). SD values of artifact improved by IR method. However, IR method was not improved to CT values decreased by artifact (Phantom-A). CT values were not changed by the difference in image reconstruction methods in Phantom-B. Conclusion: IR method has an effect to reduce statistical noise, but reduced the CT value for DB artifact. On the other hand, the OSR and Boost methods are effective for the improvement of CT value in the DB artifact.