CT心脑血管一体化成像的图像质量评价

Evaluation of the image quality of integrated imaging in coronary combined with carotid and cerebrovascular computed tomography angiography

  • 摘要:
    目的 评价双源CT心脑血管一体化成像的图像质量和有效辐射剂量,探讨该方法的关键技术点,为临床提供一种评价心脑血管疾病的无创性影像学方法。
    方法 前瞻性收集临床同时行冠状动脉和头颈部动脉CT动脉成像(CTA)的连续性患者共493例。根据CT扫描机型分为2组:A组300例,采用第三代双源CT前瞻性心电门控大螺距模式扫描,根据心率进一步分为A1组(n=69,心率≤65次/分)和A2组(n=231,心率>65次/分);B组193例,采用第二代双源CT前瞻性心电门控大螺距模式扫描,根据心率进一步分为B1组(n=92,心率≤65次/分)和B2组(n=101,心率>65次/分)。分别客观、主观地评价图像质量,计算辐射剂量。计量资料采用独立样本t检验,患者临床资料中的频数参数构成比采用χ2检验,评价图像质量评分一致性采用Cohen Kappa分析。
    结果 (1)A组和B组患者间年龄(t=0.58,P=0.847)、性别(χ2=1.45,P=0.228)、体重指数(t=1.20,P=0.277)差异均无统计学意义。(2)图像质量客观评价:A组颈总动脉、颈内动脉、大脑中动脉和椎动脉V4段CT值、噪声均低于B组,差异均有统计学意义(t=1.98~4.49,均P < 0.05),两组患者的主动脉根部CT值(t=0.68,P=0.495)和噪声(t=0.31,P=0.755)差异无统计学意义。(3)图像质量主观评价的一致性Kappa值为0.912。①与B组进行比较,A组的冠状动脉CTA平均图像质量的评分更好(t=0.018,P=0.001)、冠状动脉4级血管基于患者数的不可诊断率更低(χ2=6.63,P=0.014),且差异均有统计学意义;②与B组进行比较,A组的头颈部CTA评分更好(t=0.013,P=0.004)、头颈部4级血管基于患者数的不可诊断率更低(χ2=4.38,P=0.036),且差异均有统计学意义;③A组有效辐射剂量为(1.48±0.33)mSv,较B组(2.14±0.52)mSv降低了30%,差异有统计学意义(t=14.79,P=0.001)。
    结论 第三代双源CT心脑血管一体化成像采用不同心率采集不同扫描时间窗的办法,能提供较好的图像质量,且降低了辐射剂量,是一种评价心脑血管疾病的无创性影像学方法。

     

    Abstract:
    Objective To evaluate the image quality, radiation dose and key technologies of integrated imaging in coronary combined with carotid and cerebrovascular computed tomography angiography (CTA), which hopes to offer a non-invasive imaging method for cardiovascular and cerebrovascular diseases evaluation.
    Methods A total of 493 symptomatic patients referred for simultaneous coronary, carotid, and cerebrovascular CTA were prospectively included. The subjects were divided into two groups according to CT model. Group A (300 cases), on which 3rd generation dual-source CT was performed, was further divided into groups A1 (n=69, HR ≤ 65 bpm) and A2 (n=231, HR>65 bpm), while group B (113 cases), on which 2nd generation dual-source CT was performed, was further divided into groups B1 (n=92, HR ≤ 65 bpm) and B2 (n=101, HR>65 bpm).Objective and subjective image quality and radiation dose were nalyzed, factors influencing image quality were determined, and the key technologies of the method were described. The measurement data were tested by independent sample t test, the frequency parameter composition ratio in the patient's clinical data was tested by chi-square χ2 test, and Cohen Kappa analysis was used to evaluate the consistency of the image quality score.
    Results (1) No statistically significant difference between groups A and B was found in terms of age (t=0.58, P=0.847), gender (χ2=1.45, P=0.228), and body mass index (t=1.20, P=0.277). (2)Objective evaluation of image quality:Common carotid artery, internal carotid artery, middle cerebral artery, and vertebral artery CT values and noise in group A were significantly lower than those in group B (t=1.98-4.49, all P < 0.05), although no statistically significant difference between groups was found in terms of aortic root CT values (t=0.68, P=0.495) and noise score (t=0.31, P=0.755). (3) The consistency of the image quality assessment was good (Kappa value=0.912). ① Subjective evaluation of image quality:The average coronary CTA image quality score of group A was better than that of group B (t=0.018, P=0.001), and the rate of non-diagnostic coronary grade 4 vessels based on number of patients in group A was lower than that in group B (χ2=6.63, P=0.014). ② Carotid-cerebrovascular CTA score of group A was better than group B (t=0.013, P=0.004), and carotid-cerebrovascular grade 4 vessels were less likely to be diagnosed in group A than in group B (χ2=4.38, P=0.036). ③ The effective radiation dose of group A was significantly lower than that of group B(1.48±0.33) mSv vs. (2.14±0.52) mSv; t=14.79, P=0.001.
    Conclusions Integrated imaging by coronary and cerebrovascular CTA is a non-invasive imaging method which adopted different heart rates were captured by different scan time windows can providing high image quality with significant reduction of radiation for evaluation of coronary and cerebrovascular disease.

     

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