乳腺摄影中对比度细节评价方法的探讨

Investigation of evaluation method for contrast detail in mammography

目的:使用对比度细节乳腺摄影(CDMAM)模体探索乳腺摄影中对比度细节(CD)的量化主观评价方法。方法:在28kV下,采用半自动曝光模式对CDMAM模体摄影,获得影像,然后由四位观察者观察并记录。结果:观察阈值影像质量指数(IQF)为30.35,理想IQF为20.59;高对比度分辨力指数(RH)为0.75;低对比度分辨力指数(RL)为0.76。结论:IQF值越小、RH和RL越大、观察阈值对比度细节曲线(CDC)越靠近理想CDC则影像质量越好。IQF结合CDC,可以评价摄影系统的CD探测能力,有利于质量控制基线值的建立和相互比较;可将RH、RL与客观评价参数进行比较,验证其评价能力。

Objective：To investigate the quantitative and subjective evaluation method for contrast detail （CD） using CDMAM phantom in mammography. Methods： Images were acquired by exposing CDMAM phantom under 28kV in half AEC exposing model, then evaluated and recorded by four observers. Results：The observing threshold IQF was 30.35 and the ideal IQF was 20.59. The index of high resolution（RH） was 0.75 and the index of density resolution （RL） was 0.76. Conclusion：The quality of image will be better as the less oflQF and the larger of RH and RL. And aslo, it will be better as the threshold observing CDC is closer to ideal CDC. IQF and CDC can be used to evaluate the ability in detecting CD of imaging system, and help to set up the baseline for QC. The validity of the results of RH and RL can be evalutated by comparing them with the results of objective evaluation.