An application study of ASIR technique in bladder tumor model with low-dose CT scanning
ZHAO Ya-bo1, WANG Bo1, WU Xing-jie1, MA Li-heng1, ZENG Wen-yan1, ZHUANG Niang-tuo1, YANG Qing-hua1, LIU Wei-jun1, WANG Yong-hao1, DU Sen2
1. Medical Imaging Department, the First Affiliated Hospital of Guangdong Pharmaceutical University, Guangzhou 510080, China; 2. Department of Human Anatomy, Guilin Medical College, Guilin Guangxi 541000, China
Abstract：Objective: To compare the quality and lesion conspicuity of images of bladder tumor model acquired on CT by standard-dose and low-dose with adaptive statistical iterative reconstruction(ASIR) and CT virtual cystoscopy(CTVC) imaging, and to evaluate the application of ASIR technique for low dose CT scanning of bladder tumors. Methods: A fresh porcine bladder was adopted and ligated 20 lumps(1~10 mm, ≤5 mm 13 lumps, >5 mm 7 lumps) to simulate bladder tumors. High resolution CT(GE optima CT660) with different doses(120 kVp, 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 mA) scanning was used, and 11 different levels of ASIR(0, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% and 100%) for data reconstruction were performed to get CTVC images. After objective and subjective evaluation of images collected in different conditions of different ASIR levels, the average noise, signal-to-noise ratio(SNR), contrast to noise ratio(CNR) and tumor detection rate were compared and analyzed. Results: Under the same tube current, the noise of images decreased obviously with ASIR level of 80%(P＜0.05). Under the same tube current, image SNR increased gradually with the increase of ASIR levels(P＜0.05). Under the same tube current, image CNR increased gradually with the increase of ASIR levels(P＜0.05). Under a constant tube current, the lesion detection rate did not increase obviously with the increase of ASIR levels(P＞0.05). Conclusion: ASIR technique can improve the quality of low-dose CT images of the bladder with reduction of radiation dose. ASIR technique cannot obviously improve the lesion detection rate of the bladder CTVC images.
2015, Vol. 26 
