基于模型的迭代重建中降噪设置对减小CT血管成像辐射剂量的实验研究

发布时间：2018-02-25 19:16

本文关键词： 体层摄影术 X线计算机血管造影术图像处理计算机辅助算法迭代重建技术辐射剂量　出处：《中国医学影像学杂志》2017年11期 　论文类型：期刊论文

【摘要】：目的通过模型实验探讨基于模型的迭代重建(MBIRn)中降噪设置在降低CT血管造影(CTA)辐射剂量中的应用价值。资料与方法使用能谱CT在固定管电压120 k Vp,10、50、150、600 m A不同管电流条件下,扫描静止状态容纳8支试管的血管模型。试管内分别填满纯净水、1、2、5、10、20、30 mg I/ml溶液和30 mg Ca/ml溶液。原始扫描数据分别使用标准算法FBP、ASIR40(40%ASIR与FBP混合)、MBIRc和MBIRn中优化空间分辨率设置MBIR_(RP20)、标准设置MBIR_(Stnd)、降噪设置MBIR_(NR40 )6种算法重建层厚0.625 mm的图像后进行对比分析。选取3个固定层面在试管中心及周围酯性基质放置感兴趣区,并测量CT值与标准差(SD),以代表噪声。计算并比较降噪设置MBIR_(NR40)与其他重建算法图像各溶液噪声和对比噪声比(CNR)的平均值。结果在不同管电流条件下,与FBP相比,ASIR40、MBIRc、MBIR_(RP20)、MBIR_(Stnd)和MBIR_(NR40)均不同程度减少噪声和提高CNR;MBIR_(NR40)平均噪声最低(降低78.33%),CNR最大(升高241.74%),优于其他重建算法图像(P0.05);且辐射剂量越低,其优势越明显。10 m A条件下MBIR_(NR40)重建图像噪声与600 m A条件下FBP和ASIR40相近,其余管电压条件下CNR明显大于FBP和ASIR40。结论MBIRc、MBIRn和ASIR重建算法有助于提高CTA图像质量,降低辐射剂量。MBIRn降噪设置MBIR_(NR40)噪声最低,CNR最大,且辐射剂量越小,其优势越明显。
[Abstract]:Objective to explore the model test model based iterative reconstruction (MBIRn) in noise reduction in reducing CT angiography (CTA) application value of radiation dose. Materials and methods using spectral CT in fixed tube voltage of 120 K Vp, 10,50150600 m A of different tube current conditions, a static state scan to accommodate 8 tubes of blood vessels pure water filled tube model. Respectively, the 1,2,5,10,20,30 mg I/ml solution and 30 mg Ca/ml solution. The original scan data using standard FBP algorithm respectively, ASIR40 (40%ASIR, MBIR_ and FBP mixed) set to optimize the spatial resolution of MBIRc and MBIRn (RP20), MBIR_ (Stnd), set the standard noise reduction MBIR_ (NR40) 6 comparative analysis of image reconstruction algorithm with the thickness of 0.625 mm. After selecting 3 fixed level placed in the regions of interest in the tube center and surrounding ester substrates, and the measurement of CT value and standard deviation (SD), on behalf of calculation and comparison of noise reduction noise. Set MBIR_ (NR40) and other image reconstruction algorithms for each solution of noise and contrast to noise ratio (CNR). The average value of the results in different tube current conditions, compared with FBP, ASIR40, MBIRc, MBIR_ (RP20), MBIR_ (Stnd) and MBIR_ (NR40) have different degrees of reduction noise and high CNR; MBIR_ (NR40) the average noise lowest (78.33% reduction), CNR (maximum increase 241.74%), better than other image reconstruction algorithm (P0.05); and the radiation dose is low, its advantages are more obvious under the condition of A.10 m MBIR_ (NR40) reconstruction image noise and 600 m A under the condition of FBP and ASIR40 is similar to that of the rest of the tube voltage under the condition of CNR was significantly higher than that of FBP and ASIR40. MBIRc and ASIR MBIRn conclusion, reconstruction algorithm is helpful to improve the image quality of CTA, reduce the radiation dose of.MBIRn MBIR_ (NR40) noise reduction noise minimum, maximum CNR, and the radiation dose is small, its advantage is more obvious.

【作者单位】：陕西中医药大学附属医院医学影像科;
【分类号】：R816.2

【相似文献】