| 郑敏文,赵宏亮,徐健,葛雅丽,石明国,张劲松,彭勇,宦怡.多层螺旋CT主动脉低剂量与常规剂量扫描的对照研究[J].中国医学影像技术,2008,24(3):443~446 |
| 多层螺旋CT主动脉低剂量与常规剂量扫描的对照研究 |
| Low dose spiral CT of aortography: comparison with conventional dose CT |
| 投稿时间：2007-12-07 修订日期：2008-01-11 |
| DOI： |
| 中文关键词: 主动脉造影 体层摄影术,X线计算机 |
| 英文关键词:Aortography Tomography, X-ray computed |
| 基金项目: |
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| 中文摘要: |
| 目的 探讨主动脉低剂量扫描的可行性及不同体重条件下满足诊断的最低mA量。 方法 研究分两步,初步筛选58例扫描70例次各种可疑主动脉病变或术后随访病例,随机抽取10例为常规剂量350 mA扫描,低剂量组按体重分为＜65 kg,65~75 kg,＞75 kg三组,分别采用管电流为50、100、150 mA,其余扫描参数同常规剂量组。记录单次加权CT剂量指数(weighted CT dose index, CTDIvol)、扫描长度和平均剂量长度乘积(dose length produce, DLP)。对不同低剂量组的主动脉图像满足诊断率进行比较,并进行统计学处理。第二步筛选60例各种夹层动脉瘤,针对不同体重组采用高一个50 mA等级的低剂量扫描(100、150、200 mA),记录并分析相应CTDIvol和DLP,评价图像质量及满足诊断率。 结果 初步研究采用50、100、150 mA的CTDIvol仅为常规剂量350 mA的11.3％、29.0％和42.7％,各组DLP值与常规剂量组相比均有统计学意义(P＜0.001),但50 mA组的诊断符合率仅为60％。第二步研究采用100、150、200 mA 的CTDIvol为常规剂量的29.0％、42.7％和57.3％,各低剂量组DLP与常规剂量组两两比较差异均有统计学意义(P＜0.001),且各组满足诊断率均达到100％。轴位及各种三维重建图像显示良好。 结论 适当的主动脉低剂量扫描可以替代常规剂量扫描。夹层动脉瘤应采用略高于其他主动脉病变的管电流。低剂量200 mA可普遍适用于各主动脉病变的扫描成像与正确诊断。 |
| 英文摘要: |
| Objective To explore the possibility of multi-slice low dose CT scan in the examination of the aorta and to find the rational lowest tube current. Methods The study fell into two steps. The former had 58 cases (70 times scans), with 10 undergoing conventional dose and 60 undergoing low dose. According to body weight, the subjects were classified into three groups as <65 kg, 65-75 kg, and >75 kg. Parameters for scanning with lower dose were tube current 50, 100 and 150 mA. As for conventional dose, parameters were the same with the low-dose group except for a tube current at 350 mA. Weighted CT dose index (CTDI), scanning lenth and dose length produce (DLP) were record when scanning. TXuhe rate of diagnostic accuracy of imagings from low dose groups were compared and the date were carried out statistical treatment. Second step observe 60 dissecting aneurysms, undergoing lower dose with 100, 150 and 200 mA. CTDI and DLP were record and analysed. The qualities of imagings and the rate of diagnostic accuracy were evaluated. Results During the first step, the CTDI of 50, 100 and 150 mA are 11.3%, 29.0% and 42.7% of 350 mA, respectively. DLP values of low dose groups were statistically lower than that for conventional group (P＜0.001). However, the rate of diagnostic accuracy of 50 mA group is only 60%. At the second step, the CTDIvol of 100mA, 150 mA and 200 mA are 29.0%, 42.7% and 57.3% of 350 mA, respectively. DLP values of low dose groups were also statistically lower than that for conventional group (P＜0.001). Low dose groups all have good three-dimentional reconstruction imaging qualities and the diagnostic accuracy were 100%. Conclusion Lower dose CT is able to replace conventional dose one in aortic imaging. Dissecting aneurysms should use higher tube current than other aortic diseases. A low dose of 200 mA can satisfy all imaging of aortic diseases. |
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