Modulation transfer function (MTF) measurements using IndoQCT and ImQuest on images of AAPM CT performance phantom

The modulation transfer function (MTF) in compted tomography (CT) images can be measured using software tools such as IndoQCT and ImQuest. However, the accuracy of the resulting MTF curves from these two softwares has not been compared. Therefore, this study aims to compare the edge MTF curves obtained using ImQuest and IndoQCT software, and the point MTF curves obtained using IndoQCT on the images of the AAPM CT Performance phantom. The phantom images were reconstructed with filter variations of abdominal, bone, brain, lung, sharp, smooth, and soft tissue. MTF curves can be obtained from edge of the object by the IndoQCT and ImQuest. A region of interest (ROI) was placed on the selected object (Polyethylene) in the 610-02 module of the phantom to obtain the object edge response, which was then processed to obtain the MTF curve. In addition, a MTF can obtained from point object of the 610-03 module using IndoQCT. We compared all MTFs obtained from IndoQCT and ImQuest. The MTFs obtained with ImQuest showed comparable results to those from IndoQCT for the seven filter variations. The edge method produces slightly higher MTF curves compared to the point method. It is also obtained that at low frequencies, the edge MTFs from ImQuest and IndoQCT are similar. However, at high frequencies, the response of MTFs obtained with ImQuest are slightly higher than those from IndoQCT. Based on results, IndoQCT and ImQuest demonstrated the ability to generate accurate MTF curves.