高分辨靶重建模式优化宝石CT成像

摘要

Objective To explore the value of high resolution reconstruction for optimization of imaging quality of GE Discovery CT 750 HD based on phantom pilot.Methods CT scanning with large (50 cm) and small (32 cm) scanning field of view (SFOV) was performed for a Catphan 500 phantom with or without high resolution on GE Discovery CT 750 HD.All raw data acquired by volumetric CT scan were reconstructed as the same size of a small DFOV (25 cm) with STAND algorithm.Then the images were divided into four groups,including large SFOV without high resolution (group A),large SFOV with high resolution (group B),small SFOV without high resolution (group C) and small SFOV with high resolution (group D).The spatial-resolution (SR),density-resolution (DR),noise (N),CNR,SNR and CT dose index volumes (CTDI) were measured and compared among 4 groups.Results The overall differences of SR,DR,N,CNR,SNR and CTDI were statistically significant among four groups (all P＜0.05).Compared with group A,the average N increased in group C (P＜0.01),SR increased in group B and the average CNR and SNR decreased in group D,while N increased in group D (all P＜0.01).Conclusion Large SFOV combined with high resolution reconstruction may ensure CNR and SNR,and improve SR.%目的 以体模实验为基础,观察高分辨靶重建模式优化宝石CT成像的价值.方法 采用宝石CT不同的扫描野(SFOV;50 cm vs 32 cm)对Catphan 500体模分别进行高分辨和非高分辨模式扫描,并对原始数据以相同大小的显示野(25 cm)进行STAND算法重建成像.根据不同成像方式,将所有图像分为SFOV 50 cm+非高分辨组(A组)、SFOV50 cm+高分辨组(B组)、SFOV 32 cm+非高分辨组(C组)和SFOV 32 cm+高分辨组(D组),测量并比较各组图像噪声、SNR、CNR、空间分辨率、密度分辨率及CT剂量指数(CTDI).结果 4组噪声、SNR、CNR、空间分辨率、密度分辨率及CTDI差异均有统计学意义(P均＜0.05).C组较A组噪声增加(P＜0.01);与A组比较,B组空间分辨率提高,D组CNR、SNR均降低(P均＜0.01),且噪声升高(P＜0.01).结论 选择高分辨靶重建模式,不增加图像噪声,并可保证对比噪声比和信噪比,提高空间分辨率.