第二代双源CT Flash Spiral模式高心率冠状动脉成像的图像质量及准确性评价

目的评价第二代双源CT大螺距前瞻性螺旋扫描（Flash Spiral）高心率冠脉成像的图像质量、准确性及有效射线剂量。方法前瞻性入选心率〉65次／min的连续性患者268例,随机分为两组。A组134例,采用Flash Spiral模式扫描,采集图像时间为RR间期20％-30％;B组134例,采用回顾性心电门控扫描模式（Spiral）扫描。30d内A组有47例行冠状动脉造影术（CCA）检查（A1组）,B组中有45例行CCA检查（B1组）。比较两组患者一般情况、图像质量评分、图像噪声、对比信噪比（CNR）和有效射线剂量。以CCA结果为金标准,分别计算A1、B1两组FlashDSCT显示冠脉病变的敏感性、特异性、准确率、阳性预测值和阴性预测值。结果①两组患者一般情况比较差异无统计学意义。②两组不可诊断节段基于血管节段评价分别为1．52％和1．74％,基于患者评价分别为7．5％和6．7％,差异均无统计学意义（P=0．345,P=0．812）。两组图像质量评分均数分别为1．064±0．306和1．084±0．327,差异无统计学意义（P=0．063）。A组平均图像噪声19±27（21．4±4．5）HU,CNR6．4-25．3（12．1±4．2）：B组分别为19±28（20．9±4.3）HU和7．1-28．2（13．8±5．1）,两组比较差异无统计学意义。③心率变异性：A组图像质量评分3分的病例平均心率变异性明显小于B组。④与CCA比较,两组患者评价冠状动脉狭窄的敏感性、特异性差异均无统计学意义。⑤射线剂量：A组平均有效射线剂量显著低于B组[（1．04±0．16）mSv比（7．05±1．05）mSv,P=0．001]。结论高心率患者（心率〉65次／min）采用Flash双源CT大螺距前瞻性心电门控螺旋扫描在RR间期20％±30％成像,图像质量、准确性与回顾性心电门控扫描接近,而有效射线剂量显著减低。心率变异性对高心率患者FlashSpiral模式扫描图像质量的影响较大。     

Flash双源CT大螺距冠状动脉成像与冠状动脉造影对比的临床研究

目的评价Flash双源CT大螺距前瞻性心电门控扫描模式（flashspril）诊断冠状动脉狭窄的准确性。方法30例患者行Flash双源CT冠状动脉成像（CTCA）后进行冠状动脉造影术（CCA）检查。以冠状动脉造影术结果作为金标准,统计Flash双源CTCA显示冠脉病变的敏感性、特异性、阳性预测值和阴性预测值,统计冠状动脉各段图像质量评分及有效射线剂量。结果①准确性评价：基于节段水平分析,敏感性93．2％,特异性96．8％,阳性预测值86．0％,阴性预测值98．5％。基于血管水平分析,敏感性97．9％,特异性83．8％,阳性预测值88．7％,阴性预测值96．8％。基于患者水平分析,敏感性、特异性、阳性预测值、阴性预测值均为100％。CTCA显示冠状动脉狭窄结果与CCA高度一致。②图像质量：右冠状动脉不可诊断血管节段占右冠状动脉的3．4％,左冠状动脉主干、前降支不可诊断血管节段为0,回旋支不可诊断血管节段低于1．0％。③射线剂量：平均有效射线剂量（1．72±0．10）mSv。结论Flash双源CTflashspril模式CTCA评价冠状动脉狭窄的准确性高,图像质量好,运动伪影小,有效射线剂量低。     

双源CT两种冠状动脉造影扫描方法及辐射剂量对比研究

目的优化双源CT冠状动脉成像的扫描方案,降低患者冠状动脉成像的辐射剂量。方法分析268例心率规律且小于70次／min双源CT冠状动脉成像患者病例资料,前瞻性心电门控及回顾性心电门控检查患者各134例,观察两者成像质量,比较两者单次扫描CT容积剂量指数（CTDIvol）及剂量长度乘积（DLP）。结果在扫描范围、对比剂种类速率和注射部位完全相同的情况下,前瞻性心电门控组质量评分（3．71±0．52）分,回顾性心电门控组质量评分（3．78±0．36）分,P〉0．05。前瞻性心电门控组和回顾性心电门控组在CTDIvol分别为（14．02±0．02）、（79．50±10．09）mGy;有效辐射剂量分别为（3．38±0．28）、（23．84±4．35）mSv,P均〈0．05。结论在心率规律且小于70次／min的患者行前瞻性心电门控冠状动脉成像,可有效地降低患者的辐射剂量,减轻辐射损伤。     

64层CT冠状动脉成像的前瞻性与回顾性心电门控比较

目的 比较前瞻性心电门控和回顾性心电门控64层CT冠状动脉成像的辐射剂量和成像质量,探讨低剂量前瞻性心电门控CT冠状动脉成像的可行性.方法 两组心率≤65次/min各100例患者分别进行前瞻性和回顾性心电门控扫描,并采用多平面重组(MPR)、最大密度投影(MIP)、曲面重组(CPR)及容积再现(VR)多种重组技术显示冠状动脉,图像质量根据运动伪影影响分为优、良、差,使用剂量长度计算各自的有效辐射剂量,并进行统计学分析.结果 前瞻性组平均辐射剂量为(2.81±0.48)mSv明显低于回顾性组的(10.16±1.09)mSv(P＜0.01);前瞻性组诊断性冠状动脉节段和非诊断性冠状动脉节段为95.2%(1165/1224)和4.8%(59/1224),与回顾性组的94.1%(1186/1261)和5.9%(75/1261)比较,差异无统计学意义.结论 对于心率稳定在65次/min以下的患者,前瞻性心电门控64层CT冠状动脉成像,能以较低的辐射剂量达到回顾性心电门控诊断质量的影像,是切实町行的方法.     

Double Flash扫描方式在冠状动脉计算机断层扫描中的应用

目的 探讨双源计算机断层扫描（computerized tomography,CT）大螺距前瞻性心电触发采集模式（Flash模式）在冠状动脉CT中的应用价值.方法 随访中国人民解放军总医院行冠状动脉CT检查的患者120例,其中采用Double Flash扫描方式组60例（A组）,常规螺旋扫描方式组60例（B组）.入选患者在CT检查过程中心率均＜70次/min,窦性心律且节律整齐,且体质量＜100 kg.采用4分法对图像质量进行评价（1分为图像质量极好,2分为图像质量好,3分为图像质量一般,4分为图像质量差）,并记录两组患者整个扫描过程中的总有效剂量值及总剂量长度乘积.结果 两组间图像质量评分比较,差异无统计学意义（P＞0.05）.A组整个扫描过程中的总有效剂量值明显低于B组,差异有统计学意义[（2.6±0.8） mSv vs.（8.6±1.3） mSv,P＜0.05];总剂量长度乘积也明显低于B组,差异有统计学意义[（145.8±13.5） mGy·cm vs.（621.4±129.8）mGy.cm,P＜0.05].结论 双源CT大螺距前瞻性心电触发采集模式应用于心率＜70次/min的患者时与常规螺旋扫描模式比较,在保证图像质量的同时,还可显著降低辐射剂量.     

窄窗扫描技术在高心率患者320排CT冠状动脉成像中的应用研究

目的：探讨高心律患者320排CT冠状动脉成像使用前瞻性心电门控窄窗扫描技术对图像质量和辐射剂量的影响。方法80例心率在80~100次/min的患者随机分成观察组和对照组。观察组按R- R间期30％～50％进行前瞻性窄窗扫描3个心动周期,对照组按R- R间期30％～80％进行常规扫描3个心动周期,冠状动脉节段图像质量采用4级评分法评分,辐射剂量值由设备自动计算。结果可评价血管段和优良率两组间差异无统计学意义（P＞0.05）。冠状动脉总节段、右冠状动脉（RCA）、左冠状动脉主干（LM）、左前降支（LAD）和旋支（LCX）的质量评分两组间差异无统计学意义（P＞0.05）。观察组的RCA和LCX与心律波动呈中等程度负相关（r =0.41、0.47）。观察组和对照组平均辐射剂量分别为（7.63±3.29）和（12.85±2.71）mSv,差异有统计学意义（t=1.384,P＜0.05）。结论窄窗扫描技术可应用在心律波动不大的高心率患者,能明显降低辐射剂量而不影响图像质量。     

前瞻性心电触发轴位扫描技术在64层螺旋CT中的应用

目的探讨在64层螺旋CT冠状动脉成像中采用前瞻性心电触发轴位扫描技术的图像质量和辐射剂量。方法选择采用前瞻性心电触发轴位扫描技术进行64层螺旋CT冠状动脉成像的患者160例作为前瞻组。将相同扫描参数输入回顾性心电门控螺旋扫描程序,获得扫描剂量数据作为回顾组。由2名放射科医师分别进行图像重建和图像质量评价。冠状动脉图像质量分级采用4级评分法。结果 2名放射科医师在图像重建和图像质量评价方面均有良好的一致性。160例患者除8例图像有严重血管错层伪影、2例冠状动脉严重钙化,共显示1449个冠状动脉节段。1～3分以上的1431个节段(98.76%)具有较好的图像质量,可以满足临床诊断要求。前瞻组与回顾组的平均有效剂量差异有统计学意义[(3.17±1.17)mSv vs (22.09±6.72)mSv,P0.01]。结论在64层螺旋CT冠状动脉成像中采用前瞻性心电触发轴位扫描技术可在保证图像质量的同时显著降低辐射剂量。     

MDCT前置心电门控低管电压冠状动脉成像观察

目的 观察多排螺旋CT(MDCT)前置心电门控低管电压冠状动脉成像的可行性.方法 21例采用前门控100 kV管电压扫描冠状动脉患者(低压组),23例以前门控120 kV扫描患者(高压组),观察两组图像整体质量和辐射剂量.结果 与高压组比较,低压组信号强度、噪声升高,容积CT剂量指数、有效剂量降低(P＜0.05).结论 MDCT前置心电门控低管电压冠状动脉成像整体质量良好.     

小儿复杂先天性心脏病64层螺旋计算机断层摄影术成像技术探讨

目的:探讨64层螺旋计算机断层摄影术(64-MSCT)在小儿复杂先天性心脏病(先心病)中的成像技术.方法:对我院2007-07至2007-10连续经64-MSCT检查并经手术证实的复杂先心病患儿64例进行回顾性对照研究,其中男性48例,女性16例,年龄2个月～6岁(平均2.5岁).随机依照检查方法将其分为两组,扫描使用非心电门控方式组(no-ECG组),扫描使用心电门控方式组(ECG组),每组32例;比较两组间应用64-MSCT对复杂先心病的显示能力.结果:64例均经手术证实,其中ECG组确诊29例,误漏诊3例,诊断符合率为90.6%(29/32).no-ECG组确诊20例,误漏诊12例,诊断符合率为62.5%(20/32).两组的诊断符合率、准确率比较差异有统计学意义(P<0.01).两组扫描方式的有效照射剂量分别为2.23 mSv和2.55 mSv,差异无统计学意义(t=1.220,P>0.05).结论:64-MSCT的心电门控技术对小儿复杂先心病的诊断准确率高于非心电门控技术;两组扫描方式的有效照射剂量差异无统计学意义.     

心电前门控冠状动脉CT成像在快心率患者中的应用对策

目的探讨通过增加padding的方法,评估64层螺旋CT前门控冠状动脉CT成像在相对快心率患者的应用价值。方法选择心率>65/min患者30例(病例组),通过增加padding至180ms,重建40%⁸0%相位,评价冠状动脉图像质量,分析有效辐射剂量,并与30例(对照组)用回顾性心电门控螺旋CT冠状动脉重建方法辐射剂量进行对比。结果 98.3%的冠状动脉血管能够满足诊断要求,其中通过增加padding重建收缩期40%80%相位,评价冠状动脉图像质量,分析有效辐射剂量,并与30例(对照组)用回顾性心电门控螺旋CT冠状动脉重建方法辐射剂量进行对比。结果 98.3%的冠状动脉血管能够满足诊断要求,其中通过增加padding重建收缩期40%⁴5%相位窗,28.3%的冠状动脉血管图像质量改善,其中7例患者(23.3%)的12支血管(10.0%)图像质量由不能诊断改善为可以用于诊断;病例组平均辐射剂量明显低于对照组(3.5mSv vs 10.1mSv,P<0.01)。结论前门控轴扫增加padding用于相对快心率患者,可改善图像质量,避免用辐射剂量更高的回顾性心电门控螺旋CT扫描方法。     

Safety and efficacy of intravenous esmolol before prospective electrocardiogram-triggered high-pitch spiral acquisition for computed tomography coronary angiography

Background In order to acquire a high quality image with a low radiation dose, prospective electrocardiogram （ECG）-triggered computed tomography coronary angiography （CTCA） requires a stable heart rate （HR） 〈 65 beats/min. Esmolol has the advantage of reduc-ing HR. The objective of this article is to assess the value of intravenous esmolol treatment before prospective ECG-tr/ggered high-pitch spiral acquisition for CTCA. Methods From March 2013 to June 2013, 313 patients underwent prospective ECG-triggered CTCA. Two hundred and thirty two of them received esmolol before angiography. We retrospectively analyzed clinical characteristics, esmolol dose, radiation exposure dose, and the change in HR and blood pressure in these 232 patients. Results A total of 232 patients with a HR 〉 65 beats/rain before CTCA examination received intravenous esmolol treatment （mean dose of 57.26±15.39 rag）, The mean initial HR （HR1）, slowest HR （HR2）, and the HR 30 min after HR2 （HR3） were 75.06± 5.59, 60.75 ±4.00, and 75.54 ± 5.96 beats/min, respectively （HR1 vs. HR2, P 〈 0.0001; HRI vs. HR3, P = 0.377）. The mean time from esmolol administration to HR2 was 24.25 ± 4.97 s and the mean effective radiation dose was 2.28 ± 0.02 mSv. Conclusions HR could be rapidly controlled at an optimum level with intravenous esmolol before prospective ECG-triggered high-pitch spiral acquisition for CTCA. Consequently, the patients received a very low radiation dose.     

Feasibility of low-dose coronary CT angiography: first experience with prospective ECG-gating.

AIMS: To determine the feasibility of prospective electrocardiogram (ECG)-gating to achieve low-dose computed tomography coronary angiography (CTCA). METHODS AND RESULTS: Forty-one consecutive patients with suspected (n = 35) or known coronary artery disease (n = 6) underwent 64-slice CTCA using prospective ECG-gating. Individual radiation dose exposure was estimated from the dose-length product. Two independent readers semi-quantitatively assessed the overall image quality on a five-point scale and measured vessel attenuation in each coronary segment. One patient was excluded for atrial fibrillation. Mean effective radiation dose was 2.1 +/- 0.6 mSv (range, 1.1-3.0 mSv). Image quality was inversely related to heart rate (HR) (57.3 +/- 6.2, range 39-66 b.p.m.; r = 0.58, P < 0.001), vessel attenuation (346 +/- 104, range 110-780 HU; r = 0.56, P < 0.001), and body mass index (26.1 +/- 4.0, range 19.1-36.3 kg/m(2); r = 0.45, P < 0.001), but not to HR variability (1.5 +/- 1.0, range 0.2-5.1 b.p.m.; r = 0.28, P = 0.069). Non-diagnostic CTCA image quality was found in 5.0% of coronary segments. However, below a HR of 63 b.p.m. (n = 28), as determined by receiver operator characteristic curve, only 1.1% of coronary segments were non-diagnostic compared with 14.8% with HR of >63 b.p.m. (P < 0.001). CONCLUSION: This first experience documents the feasibility of prospective ECG-gating for CTCA with diagnostic image quality at a low radiation dose (1.1-3.0 mSv), favouring HR <63 b.p.m.     

Marked reduction of effective radiation dose in patients undergoing CT coronary angiography using prospective ECG gating

Coronary CT angiography (CCTA) is a rapidly evolving technology which can characterise and image sub clinical atherosclerotic plaque and visualise anatomy and quantitate stenosis. Concern about radiation exposure has limited the uptake of this technology. The aim of this study was to review the radiation dose data in 2298 consecutive patients referred to a single centre in an Australian outpatient setting over 27 months using all available radiation dose reduction strategies. Prospective ECG gating ("step and shoot") was used preferentially in 2025 patients with a mean effective dose of 3.39 ± 1.84 mSv (range 0.86-12.6 mSv). For clinical reasons only 273 patients required retrospective ECG gating, mean dose 19.21 ± 5.58 mSv (range 2.4-34.9 mSv) resulting in an 85.7% reduction in dose for the majority of patients with the low dose technique. In conclusion, most patients referred for routine CCTA can be studied with a radiation dose comparable to invasive X-ray angiography and less than radionuclide myocardial perfusion imaging.     

Comparison of diagnostic accuracy and radiation dose between prospective triggering and retrospective gated coronary angiography by dual-source computed tomography

The purpose of this study was to evaluate and compare the diagnostic accuracy and radiation dose of dual-source computed tomographic (DSCT) coronary angiography for assessment of coronary artery disease using prospective electrocardiographic triggering and retrospective electrocardiographically (ECG) gated spiral scans. One hundred sixteen patients who had undergone dual-source computed tomography and conventional coronary angiography were enrolled in this study. Fifty-four patients were scanned using retrospective ECG-gated protocols (group 1) and 62 patients using prospective ECG-triggered protocols (group 2). Diagnostic accuracy, image quality, and effective dose were compared between groups 1 and 2. Conventional coronary angiography was used as the reference standard. In total 1,709 (98.2%) coronary segments in the 116 patients were assessable with adequate image quality. Sensitivities and specificities of diagnosing coronary heart disease (≥50% stenosis) in a patient-based analysis of DSCT data were 93.3% and 88.9% in group 1 and 96.4% and 85.7% in group 2, respectively (p=0.973 and 0.761). In vessel-based analysis, sensitivities and specificities were 77.4% and 94.1% in group 1 and 79.6% and 92.3% in group 2 (p=0.983 and 0.985). Overall averaged image quality scores (using 1- to 4-point scale) in groups 1 and 2 were 3.3 ± 0.4 and 3.5 ± 0.9, respectively (p=0.268). Prevalence of good (score 3.0) and excellent (score 4.0) image qualities of coronary vessels were 95.4% in group 1 and 92.4% in group 2 (p = 0.861). Effective doses were 8.82 ± 3.50 mSv (range 3.92 to 15.36) in group 1 and 2.95 ± 1.39 mSv (range 0.99 to 6.06) in group 2 (p<0.001). In conclusion, DSCT prospective ECG-triggered coronary angiography has equivalent image quality and diagnostic value compared to that of retrospective ECG-gated scans. Radiation dose was significantly decreased using prospective electrocardiographic triggering.     

绝对时相收缩期采集降低心房颤动患者冠状动脉CT成像辐射剂量的研究

目的:研究绝对时相收缩期采集在心房颤动患者冠状动脉CT血管造影(CTA)的可行性,并与相对时相采集对照。方法:连续入组92例持续心房颤动患者,其中A组46例采用绝对时相收缩期采集(R波后200~400ms),B组46例采用相对时相收缩期采集(R-R间期:30%~50%)。对两组扫描的冠状动脉分别做图像处理。比较两组的图像质量和辐射剂量。结果:A组冠状动脉段图像质量总体评分为(1.56±0.25),B组为(1.62±0.28),两组间差异无统计学意义(P=0.283)。两组之间可诊断的冠状动脉段比率差异无统计学意义(P=0.785)。A组有效剂量5.76(3.20,8.63)mSv;B组有效剂量9.27(4.74,12.65)mSv,两组间有效剂量差异有统计学意义(P=0.001)。绝对时相采集比相对时相采集降低辐射剂量约38%。结论:在心房颤动患者绝对时相收缩期采集具有可行性,该方案比相对时相采集显著降低辐射剂量,而不影响图像质量。