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目的评价第二代双源CT大螺距前瞻性心电门控扫描模式(flashspiral)在高心率患者行CT冠状动脉成像(CTCA)中的图像质量及有效射线剂量,探讨最佳采集数据时间。方法接受第二代双源CT冠状动脉成像检查的1321例患者中,选择心率≥70次/min和心率<70次/min者各70例(A组和B组)。两组患者均采用flashspiral模式,A组患者采集图像时间为RR间期20%,B组患者为RR间期55%。比较两组患者CTCA图像质量与有效射线剂量等的差异性。结果 (1)两组患者年龄、性别、BMI、扫描时间比较,差异无统计学意义。(2)图像质量:A组不可诊断冠状动脉节段(评分3分)20段(2.1%),B组不可诊断冠状动脉节段14段(1.5%),两组不可诊断血管节段比较,差异无统计学意义。两组不可诊断节段均常发生在右冠状动脉和左冠脉回旋支。(3)射线剂量:A组平均有效射线剂量为[1.00±0.15(0.7～1.82)]mSv,B组[1.01±0.16(0.65～1.82)]mSv;两组有效射线剂量均在1mSv左右。结论 (1)高心率患者可采用大螺距进行前瞻性心电门控单个心动周期扫描成像。(2)扫描时间窗选择RR间期的20%成像图像质量好,心率上限宜在100次/min以下。(3)心率变异性是影响flashspiral扫描图像质量的重要因素。(4)高心率患者flash扫描的有效射线剂量低,仅约1mSv。
Objective To evaluate the image quality and effective radiation dose of the second generation dual-source CT large-pitch prospective ECG gating scan (flashspiral) in patients with high heart rate under CT coronary angiography (CTCA), and to explore the optimal data collection time. Methods Among the 1321 patients undergoing second-generation dual-source CT coronary angiography, 70 patients (group A and group B) with a heart rate ≥ 70 beats / min and a heart rate <70 beats / min were enrolled. The flashspiral model was used in both groups. The duration of the acquisition of images in group A was 20% of patients with RR and the duration of RR in group B was 55%. The differences of CTCA image quality and effective radiation dose between the two groups were compared. Results (1) The two groups of patients age, gender, BMI, scan time comparison, the difference was not statistically significant. (2) Image quality: In group A, coronary artery segments (score 3) were not diagnosed in 20 segments (2.1%) in group A, segment 14 coronary artery segments (1.5%) were not diagnosed in group B, The difference was not statistically significant. Two groups of non-diagnostic segments are often occurred in the right coronary artery and left circumflex artery. (3) Radiation dose: The average effective radiation dose in group A was [1.00 ± 0.15 (0.7-1.82) mSv and 1.01 ± 0.16 (0.65-1.82) mSv in group B). The effective dose of radiation in both groups was about 1 mSv. Conclusions (1) Patients with high heart rate can adopt prospective electrocardiogram gated single cardiac cycle imaging with large pitch. (2) scan time window to select 20% RR interval imaging quality, heart rate limit should be less than 100 times / min. (3) Heart rate variability is an important factor affecting the quality of flashspiral scan images. (4) high-heart rate flash scanning of patients with low effective radiation dose, only about 1mSv.