|
KMID : 1147120130190010013
|
|
Journal of the Korean Society of Imaging Informatics in Medicine
2013 Volume.19 No. 1 p.13 ~ p.20
|
|
|
Noise Level and Contrast-dependent Behavior of Spatial Frequency Response Characteristic in Iterative Reconstruction CT
|
|
Jin Hyeong-Min
Kim Jong-Hyo
|
|
|
Abstract
|
|
|
|
Iterative reconstruction (IR) technique is growingly used in clinical CT imaging due to improved image quality at lower patient doses. However, the nonlinear frequency response in different noise level and object contrast is less explored. In this paper, we evaluate noise level and contrast dependent behavior of modulation transfer function in iterative reconstruction computed tomography imaging with an in-house phantom. A multi-contrast slit phantom was created consisting of acrylic panel and aluminum foils of different thickness. Images were acquired on multi-detector CT (Discovery CT750 HD: GE) at five dose levels (10, 25, 50, 100 and 200 mAs), and were reconstructed using FBP and two IR technique (ASIR50 and VEO). Line spread functions were extracted across angled slits on image, and were Fourier transformed to evaluate the presampled MTFs of IR and FBP reconstruction techniques. The MTF50 with higher contrast showed marginally higher response (3.8~8.5%) than that of lower contrast on IR images. For the same contrast object, the spatial resolution at 10 mAs decreased to 13.9~35.6% (MTF50) in comparison with 200 mAs. Our study revealed that MTF of IR technique degrades depending on noise level at low dose scan. Therefore, we recommend that its characteristic should be considered in quantitative analysis such as lesion size measurement.
|
|
|
KEYWORD
|
|
|
puted Tomography (CT), Modulation Transfer Function (MTF), Iterative Reconstruction, Image Qualit
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|