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目的:探讨不同辐射剂量扫描方法在心脏冠状动脉多层螺旋CT成像中的效果。方法:将我院自2013年1月至2015年3月间心内科按照拟定排除标准的150例患者作为研究对象,随机分为3组,每组各50例,其中第1组作为对照组,使用常规回顾性心电门控;第2组为观察A组,使用前瞻性心电门控;第3组为观察B组,使用基于BMI优化管电流回顾性心电门控。3组患者均120 k V管电压扫描。使用370 mg I/m L非离子型碘对比剂碘普罗胺(碘海醇)。记录每组患者一般资料,测量原始轴位图像上各区的CT值,计算出各自强化的平均值,测量胸大肌的CT值,测算客观分析指标SNR、CNR和BN,并进行主观评价。对所获取的主客观指标进行统计学分析。结果:3组客观分析指标SNR、CNR、BN及主观指标RCA、LM、LAD、LCX为:对照组SNR(15.45±3.78),CNR(13.27±3.49),BR(30.44±5.53);RCA(3.62±0.54),LM(3.84±0.39),LAD(3.72±0.42);LCX(3.49±0.48),均值(3.63±0.42);观察A组SNR(15.08±3.05),CNR(13.03±2.91),BR(30.93±4.52);RCA(3.61±0.52),LM(3.82±0.42),LAD(3.68±0.49);LCX(3.52±0.51),均值(3.62±0.44);观察B组SNR(14.43±2.71),CNR(12.38±2.54),BR(32.06±3.61);RCA(3.60±0.51),LM(3.79±0.41),LAD(3.64±0.47);LCX(3.48±0.49),均值(3.59±0.43)。观察A组和观察B组以及对照组两两比较差异不显著(P>0.05);观察A组和观察B组的辐射剂量指标CTDIVOL、DLP、ED值分别为:对照组CTDIVOL(57.29±2.17),DLP(1025.37±65.38),ED(14.35±0.98);观察组A:CTDIVOL(19.86±1.45),DLP(256.84±25.93),ED(3.56±0.34);观察组B:CTDIVOL(29.84±6.19),DLP(513.54±98.43),ED(7.17±1.39)。A组显著低于对照组(0.015,0.031,0.025,0.043,0.094);B组显著低于对照组(0.015,0.031,0.025,0.043,0.044);其中观察A组的各项指标显著低于观察B组(0.014,0.016,0.025,0.014,0.012)。结论:使用256层螺旋CT前瞻性心电门控和基于BMI优化回顾性心电门控方法都能在冠状动脉成像过程中满图诊断图像质量的同时显著降低辐射剂量,其中前瞻性心电门控技术比基于BMI优化管电流回顾性心电门控方法的效果更加明显。
OBJECTIVE: To investigate the effect of different dosimetry in coronary CT angiography. Methods: From January 2013 to March 2015 in our hospital cardiology according to the proposed exclusion criteria of 150 patients as the research object, were randomly divided into 3 groups, 50 cases in each group, of which the first group as a control group, Routine retrospective ECG gating was used; group 2 was observed in group A with prospective ECG gating; group 3 was observed in group B and tube current retrospective ECG gating was used based on BMI. All three groups were scanned at 120 kV tube voltage. 370 mg I / m L non-ionic iodine contrast agent iopromide (iohexol) was used. The general data of each group were recorded. The CT values of each region of the original axial images were measured. The average values of each enhancement were calculated. The CT values of the pectoralis major muscle were measured. The subjective evaluation indexes SNR, CNR and BN were calculated. The obtained subjective and objective indicators for statistical analysis. Results: SNR, CNR, BN and subjective indicators of RCA, LM, LAD and LCX in the three groups were as follows: control group SNR 15.45 ± 3.78 CNR 13.27 ± 3.49 BR 30.44 ± 5.53 RCA 3.62 SNR (15.08 ± 3.05), CNR (13.03 ± 2.91), BR (3.84 ± 0.39), LAD (3.72 ± 0.42) and LCX (3.49 ± 0.48) (30.93 ± 4.52), RCA (3.61 ± 0.52), LM (3.82 ± 0.42), LAD (3.68 ± 0.49), LCX (3.52 ± 0.51) (12.38 ± 2.54), BR (32.06 ± 3.61), RCA (3.60 ± 0.51), LM (3.79 ± 0.41), LAD (3.64 ± 0.47), LCX (3.48 ± 0.49), mean (3.59 ± 0.43). There was no significant difference between the observation group A and the observation group B and the control group (P> 0.05). The radiation dosimeter CTDIVOL, DLP and ED of the observation group A and the observation group B were respectively CTDIVOL (57.29 ± 2.17) , DLP (1025.37 ± 65.38) and ED (14.35 ± 0.98). Observation group A: CTDIVOL (19.86 ± 1.45), DLP (256.84 ± 25.93) and ED (3.56 ± 0.34) , DLP (513.54 ± 98.43), ED (7.17 ± 1.39). A group was significantly lower than the control group (0.015,0.031,0.025,0.043,0.094); B group was significantly lower than the control group (0.015,0.031,0.025,0.043,0.044); the observed group A indicators were significantly lower than the observation Group B (0.014, 0.016, 0.025, 0.014, 0.012). CONCLUSIONS: Both 256-slice spiral CT prospective ECG gating and BMI-optimized retrospective ECG gating can significantly reduce radiation dose with full-chart diagnostic imaging during coronary angiography, with prospective ECG Control techniques are more effective than retrospective ECG-based gating methods that optimize tube current based on BMI.