80 kVp扫描联合基于原始数据的迭代重建技术在儿童副鼻窦CT检查中的应用

目的 探讨Flash双源CT低管电压80 kVp扫描联合基于原始数据的迭代重建(SAFIRE)技术在儿童副鼻窦CT检查中的价值.方法 疑鼻窦炎行CT扫描患儿60例,A组30例采用100 kVp扫描,FBP重建;B组30例采用80 kVp扫描,SAFIRE重建,强度选择3级;其余条件不变.比较两组的有效剂量及图像质量的客观指标(CT值、图像噪声、SNR、CNR)、主观评分、诊断效能等.结果 A、B两组有效剂量、图像噪声、SNR、CNR差异均有统计学意义(P均 <0.05).两组图像的主观评分差异无统计学意义(P >0.05).两组诊断结果与临床诊断结果差异均无统计学意义(P均 >0.05).结论 在儿童副鼻窦扫描中采用Flash双源CT 80 kVp扫描联合SAFIRE重建技术,在显著降低辐射剂量的同时,还可保证图像质量及诊断效能,值得临床推广.     

超大螺距Turbo Flash扫描模式在学龄前儿童胸部检查中不用镇静剂的可行性

目的 探讨超大螺距Turbo Flash扫描模式在学龄前儿童胸部检查中不用镇静剂的可行性。方法 将90例胸部CT检查前评估心理状态为紧张或恐惧的学龄前患儿按扫描时间先后分为3组,每组30例。A组患儿应用镇静剂后行常规CT扫描,开启CARE Dose 4D/CARE kV扫描模式,螺距为1.9;B组患儿应用镇静剂后行超大螺距Turbo Flash模式扫描,螺距为3.0;C组患儿不予镇静剂干预,行超大螺距Turbo Flash模式扫描。比较3组间的扫描时间、辐射剂量、图像质量及诊断效能。结果 3组间主动脉根部、脊柱后方肌肉及皮下脂肪的CT值、主动脉根部噪声、SNR、CNR差异均无统计学意义（P均>0.05）,肺窗、纵隔窗图像质量主观评分差异均无统计学意义（P均>0.05）。A组的扫描时间及辐射剂量均高于B组及C组（P均<0.05）,B组与C组间扫描时间及辐射剂量（CTDIvol、DLP、ED）差异均无统计学意义（P均>0.05）。3组中,CT诊断与临床最终诊断结果间差异均无统计学意义（P均>0.05）。结论 超大螺距Turbo Flash模式扫描可缩短扫描时间、降低辐射剂量。对心理状态为紧张或恐惧的学龄前儿童检查时,可在避免使用镇静剂的同时获得满意的图像质量。     

静脉应用艾司洛尔对CT冠状动脉造影中Double-Flash扫描模式应用率的影响

目的 观察静脉应用艾司洛尔控制心率对Double-Flash模式在CT冠状动脉造影（CTCA）中的应用率的影响。方法 对心率≤100 次/分的258例受检者行CTCA检查。将受检者随机分为两组,A组为自然心率组;B组为心率控制组,对其中心率>65次/分者静脉推注艾司洛尔注射液50 mg。CTCA中对心率≤65次/分者应用Double-Flash模式扫描,对>65次/分用回顾性心电门控模式扫描。分别记录A、B两组中两种扫描模式的使用例数、图像质量、辐射剂量及B组药物不良反应发生率。结果 Double-Flash扫描模式A组应用率为61.33%（92/150）,B组为98.15%（106/108）,差异有统计学意义（P<0.05）。A组有效辐射剂量（ED）和CT容积剂量指数（CTDIvol）分别为（3.54±0.85）mSv和（13.94±0.65）mGy,B组分别为（1.81±0.95）mSv和（3.07±0.62）mGy,差异均有统计学意义（P均<0.05）。B组中无发生药物使用不良反应者。A组98.67%（148/150）、B组96.30%（104/108）图像可诊断,差异无统计学意义（P>0.05）。结论 静脉应用艾司洛尔可安全有效地提高CTCA中Double-Flash扫描模式的应用率。     

智能最佳管电压扫描联合自动管电流调节技术降低成人胸部CT扫描辐射剂量

目的 探讨智能最佳管电压扫描(CARE kV)联合自动管电流调节(CARE Dose 4D)技术降低胸部CT扫描辐射剂量的价值。方法 将114例接受胸部CT 检查的患者随机分为2组,A组(50例)同时开启CARE Dose 4D及CARE kV,B组(64例)只开启CARE Dose 4D进行扫描,比较2组图像质量(平均CT值、噪声、SNR、CNR、主观评分等)及辐射剂量。结果 与B组相比,A组CT剂量加权指数(CTDIvol)减少约30.29%,剂量长度乘积(DLP)减少约30.41%,有效剂量(ED)减少约30.36%(P均<0.05)。A组图像噪声高于B组,差异有统计学意义(P<0.05),而2组平扫、增强图像除B组脊柱后方肌肉SNR高于A组(P<0.05)外,平均CT值、SNR、CNR差异均无统计学意义(P均>0.05),图像质量评分均在4.5分以上,病变检出率差异无统计学意义(P均>0.05)。结论 胸部CT扫描时,联合使用CARE kV和CARE Dose 4D技术,可获得优质图像,并降低辐射剂量。     

低剂量CT胰腺灌注扫描中Stellar探测器的应用

目的 比较应用新型光子探测器与常规探测器行低剂量CT胰腺灌注扫描的图像质量及灌注参数差异。方法 对36例患者行胰腺灌注扫描,其中对18例采用装配新型光子探测器的第二代双源双能CT扫描（A组）,另18例采用装配常规探测器（探测器B）的第二代双源双能CT扫描（B组）,比较两组低剂量（80 kVp,150 mA）胰腺灌注扫描的总辐射剂量、正常胰腺实质的血流量（BF）、血容量（BV）以及腹部各主要脏器的CT值、噪声、SNR差异。结果 两组患者在性别、年龄、腹围方面差异均无统计学意义（P均>0.05）,总扫描剂量无明显差异（P>0.05）,腹部各主要脏器CT值差异无统计学意义（P均>0.05）;A组图像噪声低于B组（P<0.01）,部分脏器SNR优于B组（P<0.01）,两组正常胰腺实质BF、BV均值差异无统计学意义（P>0.05）,A组 BF和BV标准差均低于B组（P均<0.01）。结论 Stellar探测器在低剂量胰腺灌注CT扫描中能降低图像噪声,提高图像质量,并使灌注参数测定结果更为可靠。     

双能量CT不同技术在低剂量对比剂头颈CTA图像优化中的对比

目的 探讨传统线性120 kVp、高级虚拟单能量重建技术与非线性融合技术在低剂量对比剂头颈部CTA图像质量优化中的应用价值。方法 对20例患者低流率（2.0 ml/s）、低剂量（总剂量20 ml）注射对比剂,双能量模式下行头颈部CTA检查,经后处理获得传统线性120 kVp（A组）、非线性融合（B组）及虚拟高级单能量40 keV（C组）图像。于MIP轴位图像上对大脑中动脉及颈内动脉图像质量进行主观评分,测量颈内动脉及大脑中动脉CT值,计算CNR;并对结果进行统计学分析。结果 3组间大脑中动脉和颈内动脉图像质量主观评分差异有统计学意义（F=38.84、37.38,P均<0.001）,B、C组大脑中动脉和颈内动脉评分均优于A组（P均<0.001）;B、C组间颈内动脉及大脑中动脉评分差异无统计学意义（P=0.32、0.16）。3组颈内动脉及大脑中动脉CT值及CNR差异有统计学意义（P均<0.001）。B、C组颈内动脉及大脑中动脉CT值及CNR均大于A组（P均<0.05）;C组颈内动脉及大脑中动脉CT值明显高于B组（P均<0.05）。B、C组颈内动脉CNR差异无统计学意义（P=0.43）,B组大脑中动脉CNR大于C组（P=0.002）。结论 虚拟高级单能量40 keV及非线性融合技术均可提高头颈CTA的图像质量,非线性融合技术可优选用于颅内血管CTA。     

基于体质量指数双能量冠状动脉CTA低剂量检查

目的 探讨基于体质量指数(BMI)低管电流自动原始数据域迭代重建(SAFIRE)技术双能量冠状动脉CTA低剂量检查的可行性。方法 将200例患者分为4组:A组(19 kg/m²≤BMI<24 kg/m²),A管电流为180 mAs,采用FBP重建;B组(BMI<19 kg/m²),A管电流60 mAs;C组(19 kg/m²≤BMI<24 kg/m²),A管电流90 mAs;D组(24 kg/m²≤BMI<30 kg/m²),A管电流120 mAs,B、C、D组采用SAFIRE-3级重建。比较4组平均CT值、图像噪声、SNR、CNR、图像质量主观评分及辐射剂量。结果 4组患者冠状动脉显示节段、图像质量主观评分、平均CT值、SD、SNR、CNR差异均无统计学意义(P均>0.05);有效剂量(ED)差异有统计学意义(P均<0.05),ED值B、C、D组分别较A组下降65.82%、55.64%、24.18%。结论 基于BMI低管电流扫描SAFIRE重建双能冠状动脉CTA检查,能够保证图像质量并大幅降低辐射剂量。     

低电压技术在基于噪声的低电流扫描冠状动脉CTA中的应用

目的 探讨基于噪声的低电流扫描联合低电压技术对冠状动脉CTA(CCTA)图像质量和辐射剂量的影响。方法 纳入因疑似冠心病而接受CCTA的156例患者,其中常规电压组103例,采用基于噪声的低电流扫描,管电压120 kV;低电压组 53例,低电流扫描同时联合低电压技术,管电压100 kV。比较两组图像质量评分、CT值、噪声、SNR、CNR值及有效辐射剂量的差异。结果 低电压组图像质量评分、CT值、噪声、SNR和CNR值均大于常规电压组(P均<0.05);两组辐射剂量差异无统计学意义。结论 基于噪声的低电流扫描联合低电压技术可实现个性化低剂量扫描,同时提高CCTA图像质量。     

超低管电流三维自适应迭代剂量降低重建CT猪结肠成像质量与辐射剂量

目的 探讨超低管电流三维自适应迭代剂量降低(AIDR3D)重建CT猪结肠成像的图像质量与辐射剂量。方法 制作10段猪结肠息肉模型,每段猪结肠黏膜设有30枚直径1~15 mm的结节样模拟息肉。对所有模型均采用640层CT机进行扫描,管电压120 kVp,电流剂量分别为10、20、30、40、50 mAs。并获得滤波反投影(FBP)和AIDR3D重建图像,不同管电流及重建方法组合10组数据:A组(10 mA,FBP)、B组(10 mAs,AIDR3D)、C组(20 mAs,FBP)、D组(20 mAs,AIDR3D)、E组(30 mAs,FBP)、F组(30 mAs,AIDR3D)、G组(40 mAs,FBP)、H组(40 mAs,AIDR3D)、I组(50 mAs,FBP)、J组(50 mAs,AIDR3D)。测算图像的噪声、SNR及CNR作为定量指标,并对图像质量进行主观定性评分。以有效辐射剂量为指标比较各组图像的辐射剂量。结果 相同管电流条件下,AIDR3D图像的噪声低于FBP图像,SNC及CNR均高于FBP图像(P均<0.05)。D组与I组图像的噪声(P=0.052)、SNR(P=0.129)及CNR(P=0.053)差异均无统计学意义。B组图像的噪声(P=0.002)高于I组,SNR及CNR均低于I组(P均<0.001)。相同管电流条件下,AIDR3D图像的质量评分高于FBP图像(P均<0.05)。D组与I组的图像质量评分差异无统计学意义(P=0.121)。B组的图像质量评分低于I组(P<0.001)。 与I组(50 mAs,FBP)比较,D组(20 mAs,AIDR3D)的有效辐射剂量降低了59.90%,差异有统计学意义(P<0.05)。结论 超低管电流(20 mAs)扫描结合AIDR3D重建的猪结肠CT图像质量可媲美常规低管电流(50 mAs)扫描结合FBP重建的图像质量,并有效减低辐射剂量。     

前后复合双流注射技术联合低剂量扫描用于头颈部CT血管造影

目的 观察前后复合双流注射技术联合低剂量扫描用于头颈部CT血管成像(CTA)的价值。方法 收集120例接受头颈部CTA检查患者,将其分为A、B、C组,每组40例,分别接受常规对比剂注射和扫描方案(A组,管电压120 kV、管电流150 mAs)、对比剂前后复合双流注射和常规扫描方案(B组,同A组)及对比剂前后复合双流注射和低剂量扫描方案(C组,管电压100 kV、自动管电流);比较3组间图像质量客观评价结果、主观评分及有效剂量(ED)的差异。结果 C组大脑中动脉及颈总动脉CT值高于A组和B组(P均＜0.05),A组与B组差异均无统计学意义(P均＞0.05);上矢状窦及右锁骨下静脉CT值在C组低于A组而高于B组(P均＜0.05)、在A组高于B组(P均＜0.05);3组间左、右颈静脉CT值及颈动脉信噪比差异均无统计学意义(P均＞0.05)。3组间图像整体主观评分差异无统计学意义(P=0.80);B组和C组右锁骨下静脉和头部动脉小分支主观评分均高于A组(P均＜0.05),B组与C组差异均无统计学意义(P均＞0.05)。C组ED小于A、B组(P均＜0.05)。结论 前后复合双流技术联合低剂量扫描用于头颈部CTA可在不影响图像质量的同时降低辐射剂量。     

大螺距双源CT采用bolus-tracking团注法冠状动脉成像的可行性

目的 评价应用缩短呼吸指令时间的团注示踪法(bolus-tracking)行大螺距双源CT冠状动脉成像(CCTA)获得图像的增强效果及有效辐射剂量.方法 收集临床疑诊为冠状动脉性心脏病的184例患者,随机平均分为两组:A组92例,采用大螺距前瞻性心电门控螺旋扫描(Flash Spiral)模式、缩短呼吸指令时间的bolus-t racking法扫描;B组92例,采用测试团注法(test-bolus)扫描.对两组图像的主动脉根部CT值、图像噪声、CNR及有效辐射剂量进行统计学比较.结果 两组图像主动脉根部CT值、图像噪声、CNR间的差异均无统计学意义(P均＞0.05).两组触发时、扫描过程中辐射剂量差异均无统计学意义(P均＞0.05).结论 双源CT大螺距前瞻性心电门控螺旋扫描CCTA中,采用缩短呼吸指令时间的bolus-tracking法可获得与test-bolus法相近的图像增强效果,而对比剂用量进一步减低.     

双源CT前瞻性心电触发大螺距扫描腹部血管成像

目的 探讨双源CT前瞻性心电触发大螺距扫描应用于腹部CTA的可行性。方法 将40例临床疑诊腹部血管疾病、接受腹部CTA检查的患者随机分为2组,对A组采用前瞻性心电触发大螺距模式扫描,B组采用常规螺旋模式扫描,分别测量两组腹主动脉、腹腔干、脾动脉、肠系膜上动脉、右肾动脉、左肾动脉、腹主动脉分叉处、背部肌肉CT值及图像噪声,记录扫描时间及剂量长度乘积,并计算SNR、CNR和有效辐射剂量(ED)。比较两组各动脉的CT值、噪声、SNR、CNR、扫描时间、ED及图像质量差异。结果 两组腹主动脉、腹腔干、脾动脉、肠系膜上动脉、右肾动脉、左肾动脉、腹主动脉分叉处的CT值、SNR、CNR和图像质量差异均无统计学意义(P均>0.05),图像噪声、扫描时间及ED差异均有统计学意义(P均<0.05)。与B组相比,A组的扫描时间缩短86.45%、ED降低72.56%。结论 双源CT前瞻性心电触发大螺距扫描腹部CTA可在获得能够满足临床诊断要求图像的前提下大幅度降低患者的辐射剂量。     

Dual-source coronary CT angiography in patients with high heart rates using a prospectively ECG-triggered axial mode at end-systole

To determine the feasibility of dual-source coronary CT angiography (CTA) using a prospectively electrocardiogram (ECG)-triggered axial mode to target end-systole in patients with high heart rates (HR) as compared with the retrospective mode. One hundred fifty consecutive patients with regular HR > 75 bpm who underwent coronary CTA were enrolled; 75 patients underwent prospectively ECG-triggered coronary CTA targeting only end-systole (Prospective Axial Group) and 75 patients underwent retrospectively ECG-gated coronary CTA (Retrospective Helical Group). The image quality of multiple coronary artery segments was evaluated and radiation doses were recorded. The diagnostic performance of coronary CTA was compared to the reference standard of invasive coronary angiography in 52 patients (35 %) (28 patients in Prospective Axial Group and 24 patients in Retrospective Helical Group). Image quality was not significantly different between the 2 groups (P = 0.784). In subgroup analysis, segment-based sensitivity, specificity, and positive and negative predictive values of coronary CTA were 98, 96, 88 and 99 %, respectively, in the Prospective Axial Group and were 97, 95, 82, and 99 %, respectively, in the Retrospective Helical Group. Mean radiation dose was significantly lower for the Prospective Axial Group than for the Retrospective Helical Group (2.9 ± 1.4 vs. 7.4 ± 3.3 mSv; P < 0.0001). Dual source coronary CTA with a prospective ECG-triggered axial mode targeting end-systole is feasible in patients with regular high HRs for evaluation of coronary artery disease. It provides comparable image quality and diagnostic value with substantially lower radiation exposure as compared to the retrospective ECG–gated helical technique.     

High-pitch coronary CT angiography with third generation dual-source CT: limits of heart rate

To determine the average heart rate (HR) and heart rate variability (HRV) required for diagnostic imaging of the coronary arteries in patients undergoing high-pitch CT-angiography (CTA) with third-generation dual-source CT. Fifty consecutive patients underwent CTA of the thoracic (n = 8) and thoracoabdominal (n = 42) aorta with third-generation dual-source 192-slice CT with prospective electrocardiography (ECG)-gating at a pitch of 3.2. No β-blockers were administered. Motion artifacts of coronary arteries were graded on a 4-point scale. Average HR and HRV were noted. The average HR was 66 ± 11 beats per minute (bpm) (range 45–96 bpm); the HRV was 7.3 ± 4.4 bpm (range 3–20 bpm). Interobserver agreement on grade of image quality for the 642 coronary segments evaluated by both observers was good (κ = 0.71). Diagnostic image quality was found for 608 of the 642 segments (95 %) in 43 of 50 patients (86 %). In 14 % of the patients, image quality was nondiagnostic for at least one segment. HR (p = 0.001) was significantly higher in patients with at least one non-diagnostic segment compared to those without. There was no significant difference (p > 0.05) in HRV between patients with nondiagnostic segments and those with diagnostic images of all segments. All patients with a HR < 70 bpm had diagnostic image quality in all coronary segments. The effective radiation dose and scan time for the heart were 0.4 ± 0.1 mSv and 0.17 ± 0.02 s, respectively. Third-generation dual-source 192-slice CT allows for coronary angiography in the prospectively ECG-gated high-pitch mode with diagnostic image quality at HR up to 70 bpm. HRV is not significantly related to image quality of coronary CTA.     

心脏电机械偶联与Flash双源CT冠状动脉成像在高心率患者中的应用(英文)

Objective To assess the image quality and effective radiation dose of prospectively electrocardiogram-triggered high-pitch spiral acquisition (flash spiral mode)dual-source CT coronary angiography in patients with high heart rate(HR).Methods From 1321 consecutive patients,seventy patients with HR≥70 bpm (group A) and seventy patients with HR<70 bpm (group B) underwent CT angiography and were prospectively included in this study.The start phase for image acquisition of the most cranial slice was selected at ...     

Novel single-source high-pitch protocol for CT angiography of the aorta: comparison to high-pitch dual-source protocol in the context of TAVI planning

Purpose Computed tomography (CT) is increasingly being used for planning purposes prior to trans-arterial valve implantation (TAVI). High-pitch protocols using a 2nd generation dual-source CT (DSCT) allow for a comprehensive assessment of the aortic valve anulus, its distance to the coronary artery ostia, the aortic bulbus and the iliofemoral arteries with very low radiation exposure and low amount of contrast agent. The aim of this study was to evaluate the image quality of a comparable high-pitch scan mode in a modern single-source CT (SSCT) system. Methods 40 patients with severe symptomatic aortic valve stenosis have been examined for planning purposes prior to TAVI. The first 20 consecutive patients were examined with a 2nd generation DSCT system using a high-pitch scan mode (pitch value 3.4) and 60 ml of contrast agent. The second group of 20 consecutive patients were examined with a 128-slice SSCT system, using a high-pitch scan mode (pitch value of 1.7) and 60 ml of contrast agent. Image quality of the aortic valve, the ascending aorta, the coronary artery ostia, the iliofemoral arteries and overall image quality were graded in a blinded fashion using a 4-point-grading-scale. Furthermore, signal intensity and image noise were derived in the ascending aorta and in the ilio-femoral arteries. Results There was a minor but significant difference in the overall image quality score with lower image quality in SSCT (3.5 ± 0.6) when compared to DSCT (3.85 ± 0.4; p = 0.037). The mean image quality score was significantly higher in patients examined in DSCT when compared to SSCT regarding the evaluability of the coronary ostia (4.0 vs. 3.5; p < 0.01) and the image quality of the ascending aorta (4.0 vs. 3.5; p < 0.01). There was no significant difference in evaluation of the aortic valve and its anulus (3.85 for DSCT and 3.65 for SSCT; p = 0.149) and image quality of the iliofemoral arteries (3.65 for DSCT and 3.85 for SSCT; p = 0.140). Signal intensity and image noise did not differ significantly between both groups. Conclusions This study presents a novel high-pitch protocol for modern SSCT scanners, which allows CT angiography for TAVI planning with a similar radiation dose and contrast agent exposition and only small compromises in image quality compared to a high-pitch protocol on a DSCT scanner.     

心房颤动患者的低剂量、大螺距双源CT冠状动脉成像的可行性研究(英文)

Objective The objective was to attempt to rule out whether high-pitch spiral acquisition dual-source computed tomography coronary angiography(CTCA)can be performed in patients with atrial fibrillation at low dose.Methods Ten patients with atrial fibrillation who were admitted for a first diagnostic coronary angiogram were screened for participation.All patients underwent dual-source CT.Patients were performed CTCA using the prospectively ECG-gated high-pitch mode and retrospective ECG gating spiral acquisition respectively with their permissions.The start phase for image acquisition of the most cranial slice was selected at 20%-30% of the R-R interval in all patients.Results Image qualities of prospectively ECG-gated high-pitch mode were rated as being excellent in 7 cases of all the patients and only 3 cases′ image qualities were graded score 2.By using retrospective ECG gating spiral acquisition mode,non-diagnostic image quality (score 3) occurred in 4 patients which were observed in RCA and 1 patient in LCX.The estimated radiation dose ranges from 0.68 to 1.887 mSv in flash mode and the radiation dose of spiral mode were very high ranging from 14.92 to 29.308 mSv.Conclusions Our case series suggest that patients with atrial fibrillation rhythm can be performed CTCA with high-pitch spiral acquisition mode.20%-30% of the RR interval window for data acquisition for high-pitch dual-source CTCA may probably obtain good image quality with low doses.     

第二代双源CT Flash Spiral模式冠状动脉成像在心房颤动患者中的应用

目的：评价心房颤动患者采用第二代双源CT前瞻性心电门控螺旋扫描模式（Flash Spiral模式）冠状动脉成像图像质量及有效射线剂量,初步观察心房颤动患者采用Flash Spiral模式冠状动脉成像的可行性。方法入选我院接受大螺距双源CT冠状动脉成像的心房颤动患者54例,随机分为2组：A组采用Flash Spiral模式扫描（n＝34）;B组采用Spiral模式扫描（n＝20）。分别测量两组患者主动脉根部CT值、对比信噪比（CNR）冠状动脉图像质量评分及有效辐射剂量并比较;记录患者的心率、心率变异性,分析其对图像质量的影响。结果（1）两组患者年龄、性别、BMI、心率、心率变异性、扫描长度比较,差异无统计学意义。A组扫描时间显著短于B组[（0.27±0.01）s vs.（5.81±0.93）s,t＝34.72,P＜0.001]。（2）两组间CNR差异无统计学意义（12.1±4.2 vs.13.8±5.1,t＝0.48,P＝0.31）。A组平均图像质量评分优于B组[（1.10±0.49）分vs.（1.21±0.70）分,t＝-2.48,P＝0.013]。基于节段分析,A组不可诊断节段低于B组（2.2%vs.5.1%,χ2＝4.70,P＝0.03）,基于患者评价,A组与B组不可诊断病例比较差异无统计学意义（7.8%vs.16.7%,χ2＝2.97,P＝0.08）。（3）两组不可评价血管病例的平均HRV均显著高于可评价血管病例的平均HRV[A组（21±7）次/min vs.（38±4）次/min,t＝-6.194,P＝0.001;B组（22±7）次/min vs.（34±12）次/min,t＝-2.73,P＝0.014]。（4）A组有效辐射剂量显著低于B组[（0.89±0.127）mSv vs.（11.03±2.57）mSv,t＝-23.09,P＜0.001]。结论与传统的回顾性心电门控螺旋扫描相比,心房颤动患者采用第二代双源CT Flash Spiral模式冠状动脉成像成功率较高,图像质量较好,有效辐射剂量明显减低。     

双源CT大螺距Flash模式与双能模式在头颅血管成像中的图像质量和辐射剂量研究

目的：比较在头颅CT动脉造影（CTA）成像中,双源CT的大螺距Flash模式与双能模式（DECT）在成像质量,辐射剂量方面有无区别。方法从2012年8月～2013年1月疑似颅内动脉瘤109例患者中,选出两组不同检查模式的病例,每组20例。两名医师对图像质量进行5级评分,同时比较两组的CT容积剂量指数（CTDIvol）、剂量长度乘积（DLP）。结果 Flash组和DECT组扫描模式的CTDIvol、DLP分别为：30.17±1.74mGy,697.14±38.23mGy？cm;13.52±0.58mGy,289.92±16.56mGy？cm。两组间颅内血管的图像质量无明显差异（Z=-0.403,P=0.715）。颅底血管的椎基底动脉无统计学差异（Z=-1.286,P=0.12）,而颈内动脉C2-C5段图像质量DECT组明显低于Flash组（Z=-6.273,P＜0.001）。结论两种模式的图像质量在颅内血管和颅底椎基底动脉上无明显差异;对于颅底颈内C2-C5段,Flash模式明显优于DECT模式。Flash模式的辐射剂量要大于DECT模式。     

双源CT大螺距扫描结合正弦图迭代重建技术在小儿先天性心脏病的应用

目的 探讨双源CT大螺距扫描结合正弦图迭代重建（SAFIRE）技术在小儿先天性心脏病（简称先心病）低辐射剂量成像中的可行性。方法 选取96例心脏超声或临床拟诊复杂先心病患儿,随机分为A组、B组,每组48例,2组均行双源CT大螺距并前瞻性心电触发扫描。A组管电压采用80 kV,管电流按体质量分别设置,采用滤波反投影（FBP）重建;B组管电压与A组相同,管电流根据体质量设置为A组的50%,采用SAFIRE。分别测量并记录两组图像中升主动脉、降主动脉、主肺动脉及左心室的平均CT值及噪声（SD）,并计算SNR及对比噪声比（CNR）,由2名影像学医师以5分法主观评价图像质量。记录两组患儿的容积CT剂量指数（CTDIvol）、剂量长度乘积（DLP）值,计算有效辐射剂量（ED）。结果 两组患儿相同层面CT值、SD、SNR及CNR值差异均无统计学意义（P均>0.05）。两组图像的主观图像质量中位数评分均为4分（Z=1.02,P=0.31）,图像质量评分评价者间一致性极好（Kappa=0.84,P<0.05）。A组、B组ED分别为（0.18±0.05）mSv、（0.09±0.03）mSv（P<0.05）,B组ED较A组降低约50%。结论 对先心病患儿采用双源CT大螺距扫描联合SAFIRE技术的图像质量满足诊断要求,且可降低扫描剂量。