CT低剂量联合迭代算法对尿路结石成分的分析

发布时间：2018-05-03 02:11

本文选题：X线计算机体层摄影 + 尿路结石　；参考：《华北理工大学》2017年硕士论文

【摘要】：目的评价CT低剂量联合迭代算法对尿路结石成分分析的可行性,并探讨其最优扫描方案。方法第一部分:搜集泌尿外科手术后结石60枚,将其用蒸馏水清洗干净,自然晾干、编号,分组放于猪肾集合系统内并记录位置,然后将其放于制作的组织模型中行不同剂量CT扫描。常规剂量:120k V,400m As,采用滤波反投影算法(Filtered back projection,FBP)1mm薄层重建;低剂量:(A组:120k V,200m As;B组:120k V,150m As;C组:120k V,100m As)分别行迭代算法i Dose1-6级1mm薄层重建。扫描结束后将60枚尿路结石用红外光谱法测定其化学成分作为实验的金标准。在常规剂量FBP 1mm重建下分别测量结石软组织窗和骨窗CT值,初步判定结石化学成分;由两位放射医师采用双盲法读片并对图像质量做主观评分,记录CT容积剂量指数(CT dose Index Volume,CTDIvol)、剂量长度乘积(Dose length product,DLP)、计算有效剂量(Effective dose,ED);测量图像的客观噪声值、计算信噪比、测量结石CT值及最大长径、记录结石检出数,评价低剂量联合迭代算法对结石检出情况及图像质量的影响。第二部分:搜集78例尿路结石患者,首次检查均应用常规剂量(120k V/400m As)扫描,采用FBP1mm薄层重建,保守治疗后结石未排出,复查CT应用低剂量(120k V/150m As)扫描,行迭代算法i Dose1-6级1mm薄层重建;首先通过图像质量评估及结石检出情况评价出1mm最优的i Dose等级,再对此等级行1.5mm及2mm重建,评价出最合理重建层厚。结果1 60枚尿路结石,其中纯结石23枚(纯尿酸结石8枚),混合结石37枚;60枚结石骨窗CT值高于软组织窗CT值,但二者之间差异无统计学意义(P0.05);8枚纯尿酸结石(软组织窗和骨窗)CT值与52枚非尿酸结石的(软组织窗和骨窗)CT值之间差异有统计学意义(P0.05);根据ROC曲线分析确定纯尿酸结石的最佳临界值(CT值)为483.5HU,以此为界值诊断纯尿酸结石,其敏感度为96.20%,特异性为87.50%。低剂量各组的CTDIvol、DLP、ED与常规剂量组比较差异有统计学意义(P0.05);三组低剂量的i Dose1~6图像测量结石大小、数量、CT值与常规剂量组比较差异无统计学意义(P0.05);A组的i Dose4图像噪声、信噪比及i Dose4-6图像质量主观评分与常规剂量组比较差异无统计学意义(P0.05);B组的i Dose6图像噪声、信噪比及图像质量主观评分与常规剂量组比较差异无统计学意义(P0.05);C组的i Dose1-6图像噪声、信噪比及图像质量主观评分与常规剂量比较差异有统计学意义(P0.05)。2临床研究中低剂量组的CTDIvol、DLP、ED与常规剂量组比较差异有统计学意义(P0.05);低剂量i Dose1~6 1mm重建图像测量的结石大小、数量及CT值与常规剂量组比较差异无统计学意义(P0.05);i Dose1-5 1mm重建图像噪声、信噪比及图像质量主观评分与常规剂量比较差异有统计学意义(P0.05);i Dose6 1mm重建图像噪声、信噪比及图像质量主观评分与常规剂量组比较差异无统计学意义(P0.05);i Dose61.5mm和2mm的图像噪声与1mm的图像噪声比较差异有统计学意义(P0.05);i Dose6 1.5mm与1mm的图像信噪比比较差异无统计学意义(P0.05);i Dose62mm与1mm的图像信噪比比较差异有统计学意义(P0.05);i Dose6 1.5mm与1mm测量的结石CT值比较差异无统计学意义(P0.05);i Dose6 2mm与1mm测量的结石CT值比较差异有统计学意义(P0.05);i Dose6 2mm的结石检出数低于1mm及1.5mm的结石检出数;三组层厚结石大小及图像质量主观评分比较差异无统计学意义(P0.05)。结论1常规CT常规剂量条件下可以根据结石的CT值区分纯尿酸结石与非尿酸结石,纯尿酸结石的CT值多小于483.5HU。2在CT低剂量扫描中联合迭代算法i Dose,可以明显改善图像质量且不影响尿路结石的检出及CT值测量的准确性,可以用来评价尿路结石成分。3为达到常规图像质量水平,管电压120k V时,i Dose6水平管电流150m As为最低临界水平,此水平1.5mm层厚重建为诊断尿路结石的最优扫描方案。
[Abstract]:Objective to evaluate the feasibility of CT low dose combined iterative algorithm for the analysis of urinary calculi, and to explore the optimal scanning scheme. Method first part: collect 60 stones in the Department of Urology after surgery, clean it with distilled water, dry it naturally, numbered, and record the position in the pig kidney collection system, and then put it in the production. The conventional dose: 120K V, 400m As, the filter back projection algorithm (Filtered back projection, FBP) 1mm thin layer reconstruction, and the low dose: 60 urinary calculi after the end of the scan. Infrared spectroscopy was used to determine the chemical composition as the gold standard of the experiment. Under the routine dose FBP 1mm reconstruction, the CT values of the soft tissue window and bone window were measured respectively, and the chemical composition of the stones was preliminarily determined. The two radiologists used the double blind method and the subjective score of the image quality, and recorded the CT volume dose index (CT dose Index Volume, CTDIvol). ) the dose length product (Dose length product, DLP), the effective dose (Effective dose, ED), the objective noise value of the image, the calculation of the signal to noise ratio, the measurement of the CT value and the maximum length of the stone, the number of the stones, and the effect of the low dose combined iterative algorithm on the detection of stone and the quality of the images. The second part: 78 cases of urinary tract junction were collected. The stone patients were first examined with conventional dose (120K V/400m As) scanning, using FBP1mm thin layer reconstruction, and the stones were not discharged after conservative treatment. The low dose (120K V/150m As) scanning of CT was rechecked, and the iterative algorithm I Dose1-6 1mm thin layer reconstruction was performed. 1.5mm and 2mm reconstruction were used to evaluate the most reasonable reconstructive thickness. Results 160 urinary calculi, including 23 pure stones (8 pure uric acid stones), 37 mixed stones, 60 stone window CT values higher than the soft tissue window CT value, but no statistical difference between the two (P0.05), and 8 pure uric acid stones (soft tissue window and bone window) CT value and 52 The difference between the CT values of the non uric acid stones (soft tissue window and bone window) was statistically significant (P0.05). According to the ROC curve, the optimal critical value (CT value) was 483.5HU for the diagnosis of pure uric acid stone. The sensitivity was 96.20%, the specificity was CTDIvol in 87.50%. low dose groups, DLP, ED was worse than the conventional dose group. The difference was statistically significant (P0.05); there was no significant difference in the size, quantity and CT value of the three groups of low dose I Dose1~6 images compared with the conventional dose group (P0.05); the I Dose4 image noise in the A group, the subjective score of the image quality of the signal to noise ratio and the I Dose4-6 image were not statistically significant (P0.05) compared with the conventional dose group (P0.05). There was no significant difference in noise, signal-to-noise ratio and subjective score of image quality compared with conventional dose group (P0.05). The difference of I Dose1-6 image noise, signal noise ratio, image quality subjective score and conventional dose in group C was statistically significant (P0.05).2 clinical study in low dose group CTDIvol, DLP, ED and conventional dose groups were different Study significance (P0.05); the size, quantity and CT value of the low dose I Dose1~6 1mm reconstruction images were not statistically significant compared with the conventional dose group (P0.05); the noise of I Dose1-5 1mm reconstruction images, the signal-to-noise ratio and the subjective score of the image quality were statistically significant (P0.05) compared with the conventional dose (P0.05); I Dose6 to reconstruct the image noise, There was no significant difference in the signal-to-noise ratio and the subjective score of image quality compared with the conventional dose group (P0.05); the image noise of I Dose61.5mm and 2mm was significantly different from that of 1mm (P0.05); there was no statistical significance (P0.05) in the comparison of the image SNR of I Dose6 1.5mm and 1mm (P0.05). The difference was statistically significant (P0.05); there was no significant difference in the CT value between I Dose6 1.5mm and 1mm (P0.05); I Dose6 2mm and 1mm measured stone CT values were significant difference. The size of three groups of thick stones and the subjective evaluation of image quality were compared. The difference was not statistically significant (P0.05). Conclusion 1 conventional CT routine dose conditions can be used to distinguish pure uric acid stone and non uric acid calculi according to the CT value of stone. The CT value of pure uric acid stone is less than 483.5HU.2 combined with iterative algorithm I Dose in CT low dose scanning, which can obviously improve the image quality without affecting the detection of urinary calculi and C. The accuracy of the T measurement can be used to evaluate the urinary tract calculus component.3 to achieve the conventional image quality level. When the tube voltage is 120K V, the I Dose6 horizontal tube current 150m As is the lowest critical level, and the level 1.5mm thickness reconstruction is the best scan for the diagnosis of urinary calculi.

【学位授予单位】：华北理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：R691.4;R816.7

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