摘要
目的:探索低剂量射线对于图像质量的影响,评估低剂量CT尿路造影对输尿管病变的诊断价值。方法:将两只体重20kg实验用猪行单侧输尿管中下段不全结扎,制成肾输尿管积水模型,按常规剂量(120kV,250mAs)及低剂量(120kV,100mAs)分别扫描。每只实验用猪间隔一至两周扫描一次,共计24组图像。由两位医师按4级盲法对图像质量进行主观评分,以2.50分为界限,将所得图像分为对诊断有无影响两组。搜集进行MSCTU检查的病例39例,其中30例行常规剂量扫描(120kV,220～250mAs),9例采用低剂量扫描(120kV,100～120mAs),所有病例影像资料均行后台图像重建。根据计算机自测值对放射容积CT剂量指数进行评估。结果:动物模型常规剂量组图像质量不影响诊断的合计21次,影响诊断的有3次,而低剂量组分别为16次、8次,两者之间的差异无统计学意义(P>0.05)。临床MSCTU常规剂量组病例中输尿管结石15例,原发性输尿管癌2例,继发性肿瘤浸润6例,炎性狭窄2例,血管压迫3例,重复畸形2例。低剂量组病例中输尿管结石7例,原发性输尿管癌2例。所有病例原始横断面及后期重建图像均符合临床要求,诊断正确。根据放射容积CT剂量指数计算机自测值,低剂量组平均为11.2mGy,常规剂量组平均为27.4mGy。结论:MSCTU检查对输尿管病变的显示和诊断有明显的优越性,而低剂量扫描在某些输尿管疾病的诊断中,能够兼顾图像质量及降低辐射危害,值得在临床中应用。
Objective：To study the influence of low radiation dose in the image quality of multi-slice CT urography（MSCTU）for the diagnosis of ureteral diseases.Methods：Partial ligation of middle-distal part of unilateral ureter was carried out in two pigs with body weight as 20kg and hydronephrosis model was obtained.Routine dose（120kV,250mAs）and low dose（120kV,100mAs）MSCT scanning was undergone for the interval once by 1～2 weeks,altogether 24 times of MSCTU were carried out.The images were read by two radiologists independently and the image quality was scored according to 4 grades,the threshold of differentiating whether image quality was influenced was 2.5.In addition,39 patients with MSCTU were collected,including 30 patients with routine-dose（120kV,220～250mAs）CT scanning and 9 cases with low-dose（120kV,100～120mAs）scanning.All images of these patients were reconstructed using Advantage Workstation 4.0.The radiation dosage was evaluated according to the index calculated by computer self-measured value and radiated volume CT dose（CTDI）.Results：Of the experimental models,the diagnosis of CTU was not impacted by the image qualities in 21 times using routine radiation dose,yet it was impacted in 3 times.For low radiation dose,the image qualities were not affected in 16 times and were affected in 8 times respectively.There was no significant statistic difference existed（P〉0.05）.Of the patients with ureteric diseases using routine radiation dose for MSCTU,there were ureteral stone（n=15）,primary ureteric carcinoma（n=2）,secondary ureteric carcinoma（n=6）,inflammation and stenosis（n=2）,compression of ureter by blood vessel（n=3）and duplex anomaly of ureter（n=2）.As for the low dose group,there were ureteric stones（n=7）and primary carcinoma（n=2）.All of the axial and post-processed reconstructed images were proved to meet the requirement of clinical application and the diagnoses were correct.The radiation dose was determined by computer measurement,the mean CTDI of routine-dose was 27.4mGy and the CTDI was 11.2mGy.Conclusion：MSCTU provide comprehensive information in the diagnosis of ureteric diseases.Low radiation dose scanning also can assure the image quality and lead to lower radiation risk,which is worth promoting for clinical application.
出处
《放射学实践》
2008年第9期1026-1029,共4页
Radiologic Practice
