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目的评估双源CT(DSCT)大螺距扫描技术CT泌尿道造影(CTU)的图像质量及辐射剂量。方法疑为泌尿系统病变行CTU检查患者50例,随机均分为两组,采用DSCT行平扫、实质期、排泄期和延迟期四期螺旋扫描。A组的四期均行常规螺旋扫描;B组在延迟期使用DSCT大螺距(3.4mm)扫描。记录A、B两组延迟期辐射剂量:剂量长度乘积(DLP)和CT容积剂量指数(CTDIvol)。采用5分法评估和分析延迟期的图像质量。结果 A组延迟期的DLP为(349.52±86.08)mGycm,CDTIvol为(9.61±1.85)mGy,均明显高于B组的(145.09±18.04)mGycm和(3.54±0.81)mGy(P<0.01)。A、B两组延迟期图像质量评分相仿[(4.38±0.65)分vs.(4.04±0.58)分](P>0.05)。结论与常规螺旋扫描比较,CTU检查的延迟期使用DSCT大螺距扫描模式可大幅度降低辐射剂量,但图像质量相比未见明显降低。
Objective To evaluate the image quality and radiation dose of CT urography with dual-source CT (DSCT) large-pitch scanning technique. Methods Fifty patients suspected to be urologic lesions undergoing CTU examination were randomly divided into two groups. The patients underwent CT scan with plain, substantive, excretory and delayed phase spiral CT. All patients in group A underwent conventional spiral scanning in four phases and group B underwent DSCT large-pitch (3.4 mm) scanning in the delayed phase. Record the delayed radiation dose in group A and group B: dose length product (DLP) and CT volume dose index (CTDIvol). Use a 5-point method to assess and analyze image quality for the delay period. Results The DLP in group A was (349.52 ± 86.08) mGycm and (9.61 ± 1.85) mGy in delayed phase, which were significantly higher than those in group B (145.09 ± 18.04) mGycm and (3.54 ± 0.81) mGy (P <0.01). The image quality scores of group A and group B were similar [(4.38 ± 0.65) vs (4.04 ± 0.58)) (P> 0.05). Conclusion Compared with the conventional spiral CT scan, the DSCT large-pitch scanning mode can greatly reduce the radiation dose, but the image quality is not significantly reduced.