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胃癌是发病率位于当今全球第五的恶性肿瘤,其发病率和病死率均较高,目前主要采用以手术治疗为主的综合治疗,而术前准确的影像学分期对病人诊疗和预后至关重要[1]。研究[2]表明,CT在胃癌术前受累情况评估和术后随访方面优势明显,但病人反复接受检查所面临的辐射剂量是亟需解决的问题。模型迭代重建技术(iterative model reconstruction,IMR)是一种可以优化图像质量、降低辐射剂量的新型迭代重建技术[3]。本研究旨在探讨采取低管电压联合IMR在胃癌CT增强中的应用价值。现作报道。
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观察组CTDIvol、DLP和ED均明显低于对照组(P < 0.01)(见表 1)。
分组 n CTDIvol/mGy DLP/(mSv·cm) ED/mSv 观察组 26 3.55±0.52 179.62±13.27 2.69±0.19 对照组 28 15.24±2.03 672.86±21.01 10.09±0.32 t′ — 29.45 103.90 104.17 P — < 0.01 < 0.01 < 0.01 表 1 2组病人辐射剂量指标比较(x±s)
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观察组图像SNR、CNR均明显大于对照组(P < 0.01)(见表 2)。
分组 n SNR CNR 观察组 26 10.44±4.07 6.16±1.83 对照组 28 6.69±2.01 3.38±0.81 t — 4.24 7.13 P — < 0.01 < 0.01 表 2 2组图像客观评价指标比较(x±s)
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2名阅片医师对图像质量主观评价的一致性均较好,其中观察组图像LCD、LES、ID评分的Kappa值分别为0.728、0.783、0.803,对照组图像LCD、LES、ID评分的Kappa值分别为0.781、0.736、0.767,2组LCD和LES差异均有统计学意义(P < 0.05),而ID差异无统计学意义(P>0.05)(见表 3)。
分组 LCD LES ID 观察组 3(3, 4) 3(3, 4) 3(3, 4) 对照组 3(2, 4) 4(3, 4) 4(3, 4) Z -1.99 -2.05 -0.12 P < 0.05 < 0.05 >0.05 表 3 2组图像主观评价指标比较[M(P25, P75)]
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观察组胃癌T分期符合率为88.46%,高于对照组的64.29%(P < 0.05)(见表 4)。
CT增强T分期符合 CT增强T分期不符合 符合率/% χ2 P 观察组
对照组23
183
1088.46
64.294.31 < 0.05 表 4 2组病人CT增强诊断胃癌T分期符合率比较
低管电压联合模型迭代重建技术在胃癌CT增强中的应用价值
Application value of low-tube-voltage combined with iterative model reconstruction in the contrast-enhanced CT of gastric cancer
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摘要:
目的探讨低管电压联合迭代模型重建(IMR)技术在胃癌CT增强中的应用价值。 方法选择胃癌病人54例,均行上腹部CT平扫和动态增强扫描,其中IMR重建组26例作为观察组,滤波反投影重建组28例作为对照组,收集2组门静脉期扫描数据,对2组图像分别进行主观评价、客观评价及有效剂量比较,并以术后病理为金标准,比较2组图像CT增强T分期的符合率。 结果观察组CT容积剂量指数、CT剂量长度乘积和有效剂量均明显低于对照组(P < 0.01),观察组图像信噪比、对比噪声比均明显大于对照组(P < 0.01),2组低对比分辨力和病灶边缘锐利度差异均有统计学意义(P < 0.05),而图像失真差异无统计学意义(P>0.05)。观察组胃癌CT增强T分期符合率为88.46%,高于对照组的64.29%(P < 0.05)。 结论低管电压联合IMR应用于胃癌CT增强显示,不仅能降低辐射剂量、提高图像质量,并有助于提高胃癌术前T分期诊断符合率。 Abstract:ObjectiveTo explore the application value of low-tube-voltage combined with iterative model reconstruction(IMR) technique in the contrast-enhanced CT of gastric cancer. MethodsThe upper abdominal CT scanning and dynamic enhanced scan in 54 gastric cancer patients were examined, and the 26 patients treated with IMR reconstruction and 28 patients treated with filtered back projection(FBP) reconstruction were divided into the observation group and control group, respectively.The portal vein phase scan data in two groups were collected, and the subjective evaluation, objective evaluation and effective dose comparison of the images in two groups were carried out.The postoperative pathology results were set as the gold standard, the coincidence rate of CT enhanced T staging was compared between two groups. ResultsThe CT volumetric dose index, CT dose-length product and effective dose in observation group were significantly lower than those in control group(P < 0.01), and the image signal-to-noise ratio and contrast-to-noise ratio in observation group were significantly higher than those in control group(P < 0.01).The differences of the low contrast resolution and lesion edge sharpness between two groups were statistically significant(P < 0.05), while there was no statistical significance in image distortion between two groups(P>0.05).The coincidence rate of CT enhanced T staging in observation group(88.46%) was higher than that in control group(64.29%) (P < 0.05). ConclusionsThe low-tube-voltage combined with IMR in the contrast-enhanced CT of gastric cancer can not only reduce the radiation dose and improve the image quality, but also help to improve the preoperative T-stage diagnosis coincidence rate of gastric cancer. -
表 1 2组病人辐射剂量指标比较(x±s)
分组 n CTDIvol/mGy DLP/(mSv·cm) ED/mSv 观察组 26 3.55±0.52 179.62±13.27 2.69±0.19 对照组 28 15.24±2.03 672.86±21.01 10.09±0.32 t′ — 29.45 103.90 104.17 P — < 0.01 < 0.01 < 0.01 表 2 2组图像客观评价指标比较(x±s)
分组 n SNR CNR 观察组 26 10.44±4.07 6.16±1.83 对照组 28 6.69±2.01 3.38±0.81 t — 4.24 7.13 P — < 0.01 < 0.01 表 3 2组图像主观评价指标比较[M(P25, P75)]
分组 LCD LES ID 观察组 3(3, 4) 3(3, 4) 3(3, 4) 对照组 3(2, 4) 4(3, 4) 4(3, 4) Z -1.99 -2.05 -0.12 P < 0.05 < 0.05 >0.05 表 4 2组病人CT增强诊断胃癌T分期符合率比较
CT增强T分期符合 CT增强T分期不符合 符合率/% χ2 P 观察组
对照组23
183
1088.46
64.294.31 < 0.05 -
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