Improving low-dose abdominal CT images by Weighted Intensity Averaging over Large-scale Neighborhoods.
OBJECTIVE
Though highly desirable in radiologic procedures, low-dose CT (LDCT) images tend to be severely degraded by quantum noise and non-stationary artifacts. The purpose of this paper is to improve the abdominal LDCT images by the approach of Weighted Intensity Averaging over Large-scale Neighborhoods (WIA-LN).


METHODS
In the implementation of the proposed WIA-LN method, the processed pixel intensities are adaptively calculated as the weighted intensity averaging of the pixels with similar surrounding structures throughout a large-scale neighborhood. Both phantom and clinical abdominal CT images from a 16 detector rows Siemens CT were acquired at standard and 80% reduced tube current time products (150 mAs and 30 mAs corresponding to standard-dose and low-dose protocols, respectively). Visual comparison, statistical qualitative analysis (image quality scores and hepatic cyst diagnosis), and quantitative calculation (noise and contrast-to-noise ratio) are made.


RESULTS
Better vision and quantitative performance are realized using the proposed WIA-LN method. Compared to original LDCT and standard-dose CT (SDCT) images, statistically significant improvement of noise/artifacts suppression, contrast preservation and hepatic cyst detection in LDCT images are achieved by using the proposed method (P<0.05).


CONCLUSIONS
With the tube current reduced to approximate one-fifth of the standard tube current setting, clinically acceptable images can still be obtained by using the proposed method.
Chen
Yang
Y
The Laboratory of Image Science and Technology, Southeast University, China.
Chen
Wufan
W
Yin
Xindao
X
Ye
Xianghua
X
Bao
Xudong
X
Luo
Limin
L
Feng
Qianjing
Q
li
Yinsheng
Y
Yu
Xiaoe
X
D000328:Adult; D000368:Aged; D016477:Artifacts; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D011860:Radiography, Abdominal / Q000379:methods*; D059629:Signal-To-Noise Ratio; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*