低剂量多排螺旋CT尿路成像技术在尿路非肿瘤病变中的应用研究

The Study on Application of Low Dose Multi-Detector Computed Tomography Urography for Non-Tumorous Urinary Lesions

目的：探讨将低剂量多排螺旋CT尿路成像技术（multi-detector computed tomography urography,MDCTU,CTU）用于尿路非肿瘤病变的可行性方案.方法：参照228例体质量75 kg以下成人的腹盆部体径的平均值,制作含骨、脂肪、肌肉及肾脏组织的体部模型,将管径3-7 mm的模拟排泄期输尿管植入其中.应用GE lightspeed 16 CT机对模型进行常规剂量和一系列低剂量扫描,对获得的16个序列的影像资料进行数据分析和图像质量评价,筛选出可满足诊断要求的低剂量扫描序列,将其应用于尿路非肿瘤患者的CTU检查.共录入104例尿路非肿瘤患者,其中行低剂量CTU检查者50例（低剂量组）,行常规剂量CTU检查者54例（常规剂量组）,比较两组患者的CTU图像质量,评价低剂量CTU的临床可行性.结果：辐射剂量≥4.98 mGy的低剂量扫描序列均可满足临床诊断要求,辐射剂量为4.98 mGy的相应扫描参数为：准直（16×1.25）mm,120 kV,扫描时间0.5 s/rot、扫描层厚5 mm、螺距0.938,噪声指数14,电流60-140 mA.CTU图像对低剂量组和常规剂量组患者的诊断结果相似,仅图像质量评分有差异.结论：低剂量CTU检查扫描序列可应用于尿路非肿瘤性病变.

Objective：To explore the feasibility of applying low dose multi-detector computed tomography urography（MDCTU,CTU） for non-tumorous urinary lesions.Methods：According to the abdominal pelvic mean diameters of 228 adult humans with body mass below 75 kg,a model consisted of bones,fat,muscles and renal tissues was made.Virtual excretory phase ureter with caliber of 3-7 mm was implanted into the model.GE lightspeed 16 CT set was used for conventional and low dose scanning of the model.After the data of the 16 sequences images had been analyzed and the quality of images had been evaluated,the low dose scanning sequences conformed to the requirements of the diagnosis were selected and then used in CTU examination for patients with non-tumorous urinary lesions.In total,104 patients with suspicious non-tumorous lesions were enrolled,50 of whom underwent low dose CTU examination （low dose group）,and the other 54 cases underwent conventional dose CTU examination（conventional dose group）.The images of the two groups were compared with each other,and the feasibility of low dose CTU examination was evaluated.Results：All the low dose scanning sequences（radiation dosage ≥4.98 mGy） satisfied for the diagnostic requirements.The scanning parameters corresponded to the radiation dosage（4.98 mGy） were collimation （16× 1.25）mm,voltage 120 kV,scanning time 0.5 s/rot,thickness 5 mm,pitch 0.938,noise index 14,current 60- 140 mA.The diagnostic results based on CTU images of patients in low dose group and conventional dose group were similar.Only the scores on image quality were different.Conclusions：Low dose CTU scanning sequences could be applied for non-tumorous urinary lesions.