大螺距双源CT前瞻性心电门控扫描评价冠状动脉狭窄的临床研究

目的 评价第2代双源CT大螺距前瞻性心电门控扫描模式(Flash spiral)评价冠状动脉狭窄的准确性、图像质量及有效辐射剂量.方法 接受第2代双源CT冠状动脉成像(CTCA)检查的1077例患者中,入选采用Flash spiral模式扫描并于30 d内行冠状动脉造影(CCA)患者共73例,以CCA结果作为金标准,统计CTCA显示冠状动脉病变的敏感度、特异度、阳性预测值和阴性预测值;一致性采用Kappa值进行U检验;评价冠状动脉各段图像质量及有效辐射剂量.结果 73例患者共显示冠状动脉925节段.(1)准确性评价:基于节段水平分析,敏感度为93.2％ (164/176),特异性96.4％ (722/749),阳性预测值为85.9％( 164/191),阴性预测值为98.4％( 722/734).基于血管分析,敏感度为98.4％( 123/125),特异度为87.4％( 83/95),阳性预测值为91.1％ (123/135),阴性预测值为97.6％ (83/85).基于患者分析,敏感度为100％(44/44),特异度为89.7％ (26/29),阳性预测值为93.6％ (44/47),阴性预测值为100％ (26/26).CTCA显示冠状动脉狭窄分级与CCA高度一致.(2)图像质量:1例患者体质量指数较大,回旋支远段显影差,远端血管不可评估;2例患者由于心率变异性较大,右冠状动脉近中段有运动伪影,其余患者图像质量均较好.(3)辐射剂量:平均有效辐射剂量为(1.14 ±0.10) mSv.结论 大螺距双源CT Flash spiral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,有效辐射剂量低.     

320层CT冠状动脉成像心室率及心室率波动对图像质量、诊断结果的影响

目的评价320层CT前瞻性心电门控心室率和心室率波动对冠状动脉成像图像质量的影响,并分析诊断明显冠状动脉狭窄准确性。方法回顾分析470例患者行320层CT冠状动脉成像(CTCA)的资料,其中78例患者同时行传统冠状动脉造影(CCA)。按照扫描实时平均心室率(HR)和心室率波动的四分位间距分别分成A组〔HR<60(bpm)〕、B组(HR 61～66bpm)、C组(HR 67～71bpm)、D组(HR>72bpm)和N组(心室率波动0次)、L组(心室率波动1次)、M组(心室率波动2次)、H组(心室率波动3次以上)。分析各组冠状动脉成像的图像质量(4分法);以CCA为金标准,评价CTCA诊断显著性冠状动脉狭窄的准确性,用连续校正配对2检验比较两项检查结果之间的差异性。结果共5753个血管段中5736个血管段能够满足诊断要求,不同心室率各组之间(2=102.80,P=0.00)和心室率波动各组之间(2=58.62,P=0.00)图像质量的优良率差异有统计学意义,可评价血管段比例差异无统计学意义(2=5.97,P=0.11;2=6.91,P=0.08);图像质量与心室率(r=0.12)和心室率波动(r=0.06)呈弱的负相关。以冠状动脉血管段为评价单位,CTCA诊断显著性冠状动脉狭窄的敏感性、特异性、阴性预测值、阳性预测值、正确诊断指数分别为85%(73/86),97%(917/942),99%(917/930),75%(73/98),82%,与CCA检查结果的差异无统计学意义(2=617.26,P=0.07,Kappa=0.77);以患者为评价单位则为100%(53/53),88%(22/25),100%(22/22),96%(53/56),88%,与CCA检查结果的差异无统计学意义(2=0.02,P=0.25,Kappa=0.92)。结论本研究表明前瞻性心电门控320层CT冠状动脉成像图像质量能够较好适应高心室率和心室率波动,诊断冠心病与CCA差异无统计意义。     

第3代双源CT低剂量Turbo Flash成像图像质量与诊断效能的临床研究

目的探讨第3代双源CT大螺距前瞻性心电门控扫描模式(Turbo Flash)冠状动脉CT成像(CCTA)评价冠状动脉狭窄的准确性、图像质量及有效辐射剂量。方法前瞻性收集2016年4月至2017年4月接受第3代双源CCTA检查的患者1003例,其中有70例患者在CCTA检查后30 d内行冠状动脉造影(CAG)。对冠状动脉各节段图像质量进行评分,计算有效辐射剂量。以CAG结果为“金标准”,计算CCTA显示冠状动脉病变的灵敏度、特异度、阳性预测值和阴性预测值;CCTA与CAG评价冠状动脉狭窄分级的一致性采用Kappa值并进行U检验。结果(1) 图像质量:右冠状动脉不可诊断血管节段为0,左冠状动脉主干及前降支不可诊断血管节段为0,左冠状动脉回旋支不可诊断血管节段为0.04% (3/835)。(2)准确性评价:基于节段水平分析,Force CT诊断冠状动脉狭窄的灵敏度为97.0% (289/298)、特异度为98.3% (706/718)、阳性预测值为96.0% (289/301)、阴性预测值为98.7% (706/715);基于血管分析,灵敏度为97.5% (159/163)、特异度为85.1% (40/47)、阳性预测值为95.8% (159/166)、阴性预测值为90.9% (40/44);基于患者分析,灵敏度、特异度、阳性预测值、阴性预测值均为100%。CCTA与CAG显示的冠状动脉狭窄部位高度一致(U=2.4,P=0.008)。(3)辐射剂量:有效辐射剂量为(1.17±0.29)mSv。结论第3代双源CT Turbo Flash模式可以在自然呼吸、无心率干预下进行冠状动脉成像,扫描成功率高,图像质量佳,评价冠状动脉狭窄的准确性高,有效辐射剂量低。     

无心率(律)控制下双源CT诊断冠状动脉狭窄的价值

目的 评估无心率及心律控制下双源CT血管成像( DSCTA)诊断冠状动脉狭窄的价值.方法 随机选取89例临床怀疑冠心病患者,于2周内先后行DSCTA 和常规冠状动脉造影(CCA)检查.以CCA为标准,分析DSCTA对冠状动脉的可评价率及诊断冠状动脉狭窄的准确性,并用Kappa检验两者对冠状动脉狭窄程度诊断的一致性;评价DSCTA对急需心血管介入处置的冠状动脉中度以上狭窄(>50%)的诊断价值.结果 DSCTA对于冠状动脉的可评价率为98.6%,对高心率和极高心率组(80～120次/min和>120次/min)冠状动脉可评价率分别达99.2%和98.7%.诊断冠状动脉狭窄及中度以上狭窄的敏感性、特异性、阳性预测值、阴性预测值分别为97.9%、96.8%、89.5%、99.4%和97.2%、95.5%、80.3%、99.4%.DSCTA与CCA对冠状动脉狭窄程度诊断的一致性较好(k=0.856,P<0.01).结论 DSCT冠状动脉成像在无心率及心律控制下对冠状动脉狭窄诊断有较高的准确性和可靠性,可以作为诊断冠心病和决定冠状动脉狭窄患者是否需进一步介入干预治疗的常规筛选手段.     

双源CT低剂量前瞻性心电触发序列扫描在冠状动脉血管成像的应用

目的 研究双源CT低剂量前瞻性心电触发序列扫描技术在冠状动脉CTA的应用,并评价其图像质量.方法 将68例行冠状动脉CTA检查的患者分为2组,A组38例行前瞻性心电触发序列扫描,入组标准为心率70次/min(bpm)以下,窦性心律,心率波动范围在10 bpm以内.排除标准为心率不能控制在70 bpm以内及心律不齐患者、屏气不佳者以及冠状动脉存在严重钙化及明显狭窄者.采集期相70%R-R间期.B组30例为常规回顾性心电门控螺旋扫描,人组标准为心率70 bpm以下,窦性心律且规整.排除标准为心律不齐患者、屏气不佳者以及冠状动脉存在严重钙化及明显狭窄者.2组中管电压均随体质量指数(BMI)调整,BMI≥24 ks/m2管电压采用120 kV,BMI<24 ks/m2管电压采用100 kV.对2组扫描的冠状动脉分别做图像处理,应用秩和检验比较2组患者冠状动脉段图像质量评分,应用两独立样本t检验比较2组患者辐射剂量.结果 A组评价476段冠状动脉,B组评价372段冠状动脉.A组冠状动脉段图像质量评分为(3.48±0.59)分,B组均值为(3.53±0.58)分,2组之间比较差异无统计学意义(Z=-1.432,P=0.187).A组平均有效剂量为(2.51±0.54)mSv;B组平均有效剂量为(14.55±3.54)mSv,2组之间平均有效剂量比较差异有统计学意义(t=18.484,P=0.000).结论 在严格掌握心率及心律的基础上,可成功实现前瞻性触发序列扫描,该技术能显著降低辐射剂量而保证诊断所需图像质量.     

320排容积CT冠状动脉血管成像在心律失常患者的应用

目的 评价320排CT容积扫描在心律失常(房颤和室性早搏)患者冠状动脉CT血管成像(CTCA)的可行性及其图像质量.方法 31例持续房颤和8例室性早搏患者.经320排CTCA检查.由2名有经验的放射科医师对CT图像质量(4级评分)进行评价,分析图像质量与患者的辐射剂量.2名评价者之间的一致性采用Kappa检验.结果 31例持续房颤和8例室性早搏患者中可评估的冠状动脉血管510段,其中496段(97.2％)达到诊断要求.患者的平均辐射剂量为(12.7±4.8)mSv.2名评价者对冠状动脉评分的一致性较好(Kappa=0.72).结论 房颤和室性早搏患者的CTCA检查具有可行性,心律失常患者可以不作为检查的禁忌证,但仍须进一步降低辐射剂量.     

新型256层螺旋CT自由心率CCTA评价高心率冠状动脉狭窄患者诊断准确性

【摘要】目的：探讨新型256层螺旋CT自由心率下CCTA对高心率冠心病患者冠状动脉管腔狭窄程度的诊断准确性。方法：回顾性分析40例高心率（≥80bpm）冠心病患者,均采用自适应前瞻性心电门控且自由心率下扫描,均在CCTA检查3周内行冠状动脉造影（CGA）检查,且以CAG为金标准,计算其冠状动脉狭窄程度的敏感度、特异度、阳性预测值、阴性预测值及准确性,用Kappa检验对CCTA及CAG检测冠状动脉狭窄程度进行一致性分析。结果：40例患者共检出467个冠状动脉节段,其CCTA图像质量可诊断率达到98.93%,CAG与CCTA对诊断冠状动脉狭窄的一致性显著,kappa系数均>0.8;CCTA诊断冠状动脉狭窄节段的敏感度、特异度、阳性预测值、阴性预测值及准确度分别为96.80%、92.93%、90.30%、97.71%、94.50%,对中度狭窄、重度狭窄及闭塞的冠状动脉的诊断准确度分别为97.27%、99.03%、98.92%。结论：新型256层螺旋CT自由心率下CCTA对高心率冠心病患者冠状动脉管腔狭窄程度有较好的诊断准确性。     

320层容积CT无心率(律)控制的冠状动脉血管成像在冠心病高危人群中的初步应用

目的 探讨在无心率(律)控制条件下,320层容积CT冠状动脉血管成像(VCTA)诊断冠心病高危人群冠状动脉狭窄的准确性.方法 对30例有冠心病高危因素的患者,以冠状动脉导管造影(ICA)为金标准,评价VCTA诊断冠状动脉节段狭窄率≥50%的敏感度、特异度、阳性预测值(PPV)、阴性预测值(NPV)及Youden指数;同时采用卡方检验分析心率快慢及钙化程度对2种检查方法诊断一致率的影响.结果 30例患者平均心率(73.7±15.4)次/min(bpm),420个可分析节段的平均Agatston钙化积分中位数为45.6分(OR=181).心率＜70和≥70 bpm分别显示242和169段,诊断一致率差异无统计学意义(P＞0.05);Agatston钙化积分≥100分的图像质量和诊断一致率低于Agatston钙化积分＜100分的节段,但VCTA与ICA结果仍具有良好吻合性(P＞0.05).结论 在无心率(律)控制情况下,VCTA对冠心病高危人群的冠状动脉狭窄诊断具有很高的准确性.     

双源CT冠状动脉成像在心律失常患者中的初步应用

目的 探讨双源CT冠状动脉成像在心律失常患者中诊断冠状动脉明显狭窄的可行性及准确性.方法 连续选取60例临床高度怀疑或已确诊冠心病的患者,且行双源CT扫描过程中,出现心率变异过大(心率>14次/min)或心律失常,其中30例入院患者在2~3周内行选择性冠状动脉造影检查.以选择性冠状动脉造影为标准,从冠状动脉节段及冠状动脉分支2个角度分别评价双源CT在诊断冠状动脉明显狭窄中的敏感性、特异性、准确性、阳性预测值及阴性预测值.结果 60例出现心电信号异常患者中,心率55~269次/min,平均心率(92.8±31.9)次/min.编辑前图像质量总评分为2.26±1.03,编辑后图像质量总评分为3.50±0.61.其中30例行选择性冠状动脉造影的患者中,以冠状动脉节段为基础双源CT诊断冠状动脉明显狭窄的敏感性、特异性、阳性预测率、阴性预测率、准确性为64.0%、97.14%、76.19%、94.97%、93.0%.以冠状动脉分支为基础双源CT诊断冠状动脉明显狭窄的敏感性、特异性、阳性预测率、阴性预测率、准确性为73.81%、89.61%、79.48%、86.25%、84.03%.经χ2 检验,χ2 值分别为1.75、0.21,P值均＞0.05,双源CT与选择性冠状动脉造影比较,不管从冠状动脉节段角度还是从冠状动脉分支角度分析,两者在诊断冠状动脉明显狭窄时没有统计学意义.结论 双源CT冠状动脉成像在心律失常患者的应用是可行的,经心电编辑后图像质量明显改善,对于冠状动脉明显狭窄的诊断有较高的准确性.     

双源CT自适应前瞻性心电门控序列扫描技术在高心率患者低剂量冠状动脉成像中的应用价值

目的 评价双源CT自适应前瞻性心电门控序列扫描技术在高心率患者低剂量冠状动脉成像(CTCA)中的应用价值.方法 80例疑诊冠心病行双源CT冠状动脉成像的高心率患者,按随机数字表分成A、B两组:A组(40例)行自适应前瞻性心电门控序列扫描,B组行常规回顾性心电门控螺旋扫描.所有患者CTCA检查后2周内均行常规冠状动脉造影(CAG).采用x2检验比较A、B两组冠状动脉节段可评价率;采用两独立样本t检验评价A、B两组冠状动脉成像质量评分、辐射剂量的差异;以CAG为金标准,分别评价A、B两组CTCA诊断冠状动脉狭窄的敏感性、特异性、阳性预测值、阴性预测值,并用Kappa检验评价两组CTCA与CAG检查对冠状动脉狭窄度评估的一致性.结果 A、B两组CTCA图像质量评分分别为1.66±0.45、1.68±0.56,两组之间差异无统计学意义(=0.58、P=0.575);A、B两组CTCA冠状动脉可评价率分别为95.5％ (548/574)、95.2％ (541/568),差异无统计学意义(x2 =0.03,P=O.857);A、B两组CTCA诊断冠状动脉狭窄的敏感性、特异性、阳性预测值、阴性预测值分别是86.9％、86.6％;97.2％、97.4％;91.2％、92.8％;95.8％、94.9％;A、B两组CTCA与CAG诊断冠状动脉狭窄度的一致性均具有统计学意义(Kappa=0.856、0.853);A、B两组平均有效辐射剂量分别是(4.63±0.95) mSy、(12.67±1.94) mSv,差异有统计学意义(f=23.54,P=0.000).结论 采用双源CT自适应前瞻性心电门控序列扫描技术对高心率且心律规整患者行CTCA可获得较高的图像质量,并能准确评估冠状动脉狭窄度,同时显著降低了辐射剂量,可作为常规技术在同类机型上予以推广.     

Diagnostic Value of 64-Slice Dual-Source CT Coronary Angiography in Patients with Atrial Fibrillation: Comparison with Invasive Coronary Angiography

Objective

We wanted to evaluate the image quality and diagnostic value of 64-slice dual-source computed tomography (DSCT) coronary angiography in patients with atrial fibrillation (Afib).

Materials and Methods

The coronary arteries of 22 Afib patients seen on DSCT were classified into 15 segments and the imaging quality (excellent, good, moderate and poor) and significant stenoses (≥ 50%) were evaluated by two radiologists who were blinded to the conventional coronary angiography (CAG) results. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting important coronary artery stenosis were calculated. McNemar test was used to determine any significant difference between DSCT and CAG, and Cohen''s Kappa statistics were calculated for the intermodality and interobserver agreement.

Results

The mean heart rate was 89 ± 8.3 bpm (range: 80-118 bpm). A range from 250 msec to 300 msec within the RR interval was the optimal reconstruction interval for the patients with Afib. The respective overall sensitivity, specificity, PPV and NPV values were 74%, 97%, 81% and 96% for reader 1 and 72%, 98%, 85% and 96% for reader 2. No significant difference between DSCT and CAG was found for detecting a significant stenosis (reader 1, p = 1.0; reader 2, p = 0.727). Cohen''s Kappa statistics demonstrated good intermodality and interobserver agreement.

Conclusion

64-slice DSCT coronary angiography provides good image quality in patients with atrial fibrillation without the need for controlling the heart rate. DSCT can be used for ruling out significant stenosis in patients with atrial fibrillation with its high NPV for detecting in important stenosis.     

320排动态容积CT冠状动脉成像诊断冠心病的初步应用

目的探讨320排动态容积CT冠状动脉成像(CTA)诊断冠心病的准确性。方法 2010年3月至2010年9月对临床拟诊为冠心病的82例患者先后行冠状动脉CTA及冠状动脉造影(ICA)检查,并以ICA为金标准,评估320排CTA诊断冠状动脉狭窄≥50%及≥70%的敏感度、特异度、阳性预测值及阴性预测值。结果 CTA成像质量4分71例(86.6%),平均心率为67次/min;3分10例(12.2%),平均心率为74次/min;2分1例(1.2%),心率为83次/min;1分0例,全部病例均无阶梯伪影。CTA发现174个狭窄≥50%的节段,ICA发现144个以ICA为金标准,320排CTA诊断狭窄≥50%的敏感度、特异度、阳性预测值及阴性预测值分别为93.1%、96.0%、77.0%和99.0%。CTA发现40个狭窄≥70%的节段,ICA发现40个。以ICA为金标准,320排CTA诊断狭窄≥70%的敏感度、特异度、阳性预测值及阴性预测值分别为100%、95.6%、45.5%和100%。结论 320排CTA图像质量好,诊断冠心病准确可靠。     

Effect of Heart Rate and Coronary Calcification on the Diagnostic Accuracy of the Dual-Source CT Coronary Angiography in Patients with Suspected Coronary Artery Disease

Objective

To evaluate the diagnostic accuracy of a dual-source computed tomography (DSCT) coronary angiography, with a particular focus on the effect of heart rate and calcifications.

Materials and Methods

One hundred and nine patients with suspected coronary disease were divided into 2 groups according to a mean heart rate (< 70 bpm and ≥ 70 bpm) and into 3 groups according to the mean Agatston calcium scores (≤ 100, 101-400, and > 400). Next, the effect of heart rate and calcification on the accuracy of coronary artery stenosis detection was analyzed by using an invasive coronary angiography as a reference standard. Coronary segments of less than 1.5 mm in diameter in an American Heart Association (AHA) 15-segment model were independently assessed.

Results

The mean heart rate during the scan was 71.8 bpm, whereas the mean Agatston score was 226.5. Of the 1,588 segments examined, 1,533 (97%) were assessable. A total of 17 patients had calcium scores above 400 Agatston U, whereas 50 had heart rates ≥ 70 bpm. Overall the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) for significant stenoses were: 95%, 91%, 65%, and 99% (by segment), respectively and 97%, 90%, 81%, and 91% (by artery), respectively (n = 475). Heart rate showed no significant impact on lesion detection; however, vessel calcification did show a significant impact on accuracy of assessment for coronary segments. The specificity, PPV and accuracy were 96%, 80%, and 96% (by segment), respectively for an Agatston score less than 100% and 99%, 96% and 98% (by artery). For an Agatston score of greater to or equal to 400 the specificity, PPV and accuracy were reduced to 79%, 55%, and 83% (by segment), respectively and to 79%, 69%, and 85% (by artery), respectively.

Conclusion

The DSCT provides a high rate of accuracy for the detection of significant coronary artery disease, even in patients with high heart rates and evidence of coronary calcification. However, patients with severe coronary calcification (> 400 U) remain a challenge to diagnose.     

Diagnostic accuracy of dual-source computed tomography in the diagnosis of coronary artery disease

PURPOSE: The aim of this study was to evaluate the diagnostic accuracy of dual-source computed tomography (DSCT) with reference to invasive coronary angiography in the diagnosis of coronary artery disease (CAD) on a per-patient as well as on a per-segment basis. MATERIALS AND METHODS: Thirty-five patients with known or suspected CAD underwent both DSCT (Somatom Definition, Siemens Medical Solutions) and quantitative x-ray coronary angiography (QCA). Parameters of CT acquisition were gantry rotation time 0.330 seconds (ie, temporal resolution 83 milliseconds), tube voltage 120 kV, tube current 560 mA with ECG-triggered tube current modulation and full current at 70% of the cardiac cycle for heart rates below 70 beats per minute or full current between 30% and 80% for higher and arrhythmic heart rates. The pitch was also adapted to the heart rate, ranging from 0.2 to 0.43. Volume and flow rate of contrast material (Ultravist 370, Schering AG) were adapted to the patient's body weight. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DSCT in the detection or exclusion of significant CAD (ie, stenoses >50%) were evaluated on a per-patient and per-segment basis. RESULTS: All 35 CT angiograms were of diagnostic image quality. QCA demonstrated significant CAD in 48% (n = 17) and nonsignificant disease or normal coronary angiograms in 52% (n = 18) of the patients. Sensitivity, specificity, PPV, and NPV of DSCT on a per-patient basis were 100%, 89%, 89%, and 100%, respectively. On a per-segment basis, 473 of 481 coronary artery segments were assessable (98%). QCA demonstrated stenoses >50% in 32 segments (7%), and no disease or nonsignificant disease in 433 segments (93%). For the detection of stenoses >50% on a per-segment basis, DSCT showed a sensitivity, specificity, PPV, and NPV of 88%, 98%, 78%, and 99%, respectively. CONCLUSIONS: The comparison of coronary DSCT with QCA shows a very robust image quality and a high diagnostic accuracy in a patient-based as well as a per-segment analysis. Maximal sensitivity and NPV in the per-patient analysis show the strength of the technique in ruling out significant CAD.     

双源CT前瞻性心电门控对较高心率患者冠状动脉成像的准确性研究

目的 评价双源CT(DSCT)前瞻性心电门控对较高心率(HR)冠状动脉成像图像质量及诊断冠心病(CAD)的准确性.方法 回顾性分析103例连续患者的有创冠状动脉造影(ICA)和DSCT前瞻性心电门控冠状动脉成像资料,根据患者DSCT扫描时的心率分成3组,低心率组[<60次/min(bpm)]34例、中等心率组(60-70 bpm)36例和较高心率组(HR>70 bpm)33例.分析各组DSCT冠状动脉成像的图像质量(1～4分),以ICA为金标准,评价不同心率下DSCT前瞻性心电门控诊断CAD(狭窄≥50%)的敏感度和特异度,差异性用x2检验.结果 共1648个冠状动脉节段中的1580个(95.9%)能够满足诊断的图像质量要求,低、中、较高心率3组图像质量评分分别为(3.1±0.3)、(3.1±0.3)和(3.0±0.4)分(x2=2.80,P>0.05).各组诊断CAD的敏感度、特异度分别为82.8%(77/93)和98.4%(428/435),88.3%(91/103)和98.7%(442/448),80.3%(57/71)和98.6%(424/430)(x2值分别为0.69和0.13,P值均>0.05).总体ROC曲线下面积为0.94(95%可信区间为0.92～0.96),平均有效辐射剂量为(3.60±1.60)mSv.结论 DSCT前瞻性心电门控能够用于较高心率患者的冠状动脉成像,与较低心率组在诊断CAD时差异无统计学意义.

Abstract：

Objective To evaluate the diagnostic accuracy of dual-source CT(DSCT)prospective ECG-triggering coronary angiography in patients with different heart rate(HR).Methods One hundred and three patients with suspected coronary artery disease underwent DSCT prospective ECG-triggered coronary angiography and invasive coronary angiography(ICA).The patients were grouped by HR during CT scans:low HR(<60 bpm,n=34),medium HR(60-70 bpm,n=36)and high HR(>70 bpm,n=33).Image quality was scored using a 4-point scale.The sensitivity and specificity of DSCT in detecting≥50%stenosis were compared among subgroups where ICA was the gold standard.The differences were compared by using the X2 test of contingency on a per-segment and per-vessel basis.Results Image quality of 1580 coronary artery segments in 1648(95.9%)met the requirements for diagnosis.The image quality scores were(3.1±0.3),(3.1±0.3)and(3.0±0.4)point for subgroups(X2=2.80,P>0.05).Sensitivity and specificity were 82.8%(77/93)and 98.4%(428/435),88.3%(91/103)and 98.7%(442/448),and 80.3%(57/71)and 98.6%(424/430)for different subgroups(X2 were 0.69 and 0.13,all P>0.05).The overall area under the receiver operating characteristic(ROC)curve was 0.94(95%CI=0.92-0.96).The average effective radiation dose was(3.60±1.60)mSv.Conclusion DSCT coronary angiography with prospective ECG-triggering could be used for patients with high HR.And the diagnostic accuracy was not statistical significant between the patients with low HR and patients with medium to high HR.     

双源CT冠状动脉成像时间窗设置与辐射剂量关系的探讨

目的：双源CT冠状动脉成像时,通过对心率与全剂量时间窗关系的研究分析,来有效的降低患者的辐射剂量。方法：双源CT在心脏序列DEMO模式下,对插有左冠状动脉的胸部模体（RS-330）进行扫描。扫描参数中,只有全剂量时间窗的宽度从15%、20%、25%、35%、40%到48%不断增加,其他参数均固定不变。记录每次扫描的辐射剂量（容积CT剂量指数CTDIvol、及剂量长度乘积DLP）,每种全剂量时间窗的宽度重复扫描5次,计算5次剂量的平均值。利用SPSS11.5,得到DLP与全剂量时间窗的宽度（W）的拟合方程及拟合曲线。随机统计日常双源CT冠状动脉检查者200例,分析200例患者的心率与最佳重组期相的关系。结果：全剂量时间窗的宽度从15%、20%、25%、35%、40%到48%,其对应的DLP分别为643±7.07mGy、680±10.44mGy、712±14.58mGy、786±13.04mGy、821±9.12mGy、878±9.57mGy。利用spss得出的拟合方程及拟合曲线均为线性的。通过对200例患者的统计,心率≤65bpm时,最佳重组期相在65%～75%之间;心率≥85bpm时,最佳重组期相在35%～50%之间;心率介于65bpm～85bpm之间时,最佳重组期相在35%～75%之间。结论：全剂量时间窗的宽度越宽,患者的辐射剂量越高;患者的心率不同,则最佳重组期相不同,心率越快,最佳重组期相在一个心动周期内的位置越靠前。     

双源CT在冠状动脉造影技术方法的探讨

目的：探讨双源CT（DSCT）对冠状动脉造影具有再次重新定义的价值。方法：对520例患者进行常规冠脉造影检查,分析双源CT冠状动脉造影的技术方法,步骤及特殊的射线剂量调控技术（适应ECG门控剂量调控技术）及其功能。结果：520例患者中心率小于100次／min的患者共有390例,占75％,其平均心率为75±5．6次／min（60—100次／min）。心率高于100的患者有130例,占25％,其平均心率为（110．6＋10．8）次／min（101～130次／min）。冠状动脉重建的最佳时相均为心脏收缩期。结论：双源CT比传统CT少50％的放射剂量,在不需要控制心率的情况下完成心脏成像,提供高质量的冠状动脉和心脏图像,提高诊断冠状动脉病变的准确性。     

自然心率下128层双源Flash Spiral CT冠状动脉成像质量及辐射剂量的研究

目的 探讨自然心率下舣源CT Flash螺旋心脏模式和前瞻性心电触发序列模式的冠状动脉成像质量及辐射剂量,以实现个性化低剂量冠状动脉扫描模式的选择.方法 将60例行CT冠状动脉血管成像(CTCA)检查的患者分为2组,A组27例行Flash螺旋心脏模式扫描,入组标准:心率65次/min(bpm)以下,窦性心律且律齐,心率波动范围在±5 bpm以内.采集期相为60%R-R间期.B组33例行前瞻性心电触发序列(SAS)扫描,入组标准:(1)心率≥65 bpm,(2)心律不齐、早搏、心房颤动.排除标准:屏气不佳者.采集期相:(1)心率≤75 bpm为60%-80%R-R间期,(2)心率>75 bpm为30%-50%R-R间期,(3)心律不齐、早搏、心房颤动为20%～90%R-R间期.2组的管电压均随体质量指数(BMI)调整,BMI≥25.0 kg/m2管电乐采用120 kV,BMI<25.0 kg/m2管电压采用100 kV,A组的BMI为(24.6±1.0)ks/m2,B组的BMI为(24.6±0.9)kg/m2.对2组扫描的冠状动脉分别做图像后处理,应用两独立样本t检验对2组患者冠状动脉段图像质量评分及辐射剂量进行统计分析.结果 可评价的冠状动脉节段748段,其中A组336段、B组412段;A组冠状动脉段图像质量评价为优良者达98.2%(330/336),B组的达98.1%(404/412),2组图像质量评分差异无统计学意义(t=0.513,P=0.608).A组平均有效剂量为(0.74 4-0.29)mSv,B组为(3.67±1.37)mSv,2组之间差异有统计学意义(t=-10.858,P=0.000).结论 2组个性化低剂量冠状动脉扫描模式可在保证图像质量的同时显著降低辐射剂量.

Abstract：

Objective To compare the quality and radiation doses of coronary artery angiography under the natural heart rate condition between Flash spiral heart mode and prospective electrocardiogramtriggering sequence mode using dual-source,in order to choose personalized low doses of coronary artery scanning mode.Methods Sixty patients who underwent coronary angiography(CTA)on a 128-slice,dualsource CT scanner were divided into 2 group i.e,group A(27cases)and group B(33 cases).Flash spiral heart scan mode was employed for group A.Inclusion criteria included:heart rate<65 bpm.regular sinus rhythm,heart rate fluctuation less than ±5 bpm.Date acquisition was set at 60% of the R-R interval.Prospective electrocardiogram-triggering sequence scan mode(SAS)was performod for group B.Inclusion criteria included:(1)heart rate≥65 bpm,(2)arrhythmias,premature beat,fibrillation atrial.Exclusion criteria included:bad holding breath.Date acquisition(1)At low heart rate(≤75 bpm),date acquisition was set at 60%-80%of the R-R interval.(2)At high heart rate(>75 bpm),date acquisition was set at 30%-50%of the R-R interval. (3)At the arrhythmias,premature beat,fibrillation atrial,date acquisition was set at 20%-90%of the R-R interval.In both gronps,patients with a BMI≥25.0kg/m2 were examined with a tube voltage of 120 kV.while the other patients with a BMI<25.0 kg/m2 were examined with a tube voltage of 100 kV.The BMl was(24.6±1.0)kg/m2 in group A,while that was (24.6±0.9)kg/m2 in group B.In both groups,all images were transferred to the workstation for further processing and analysis.The imaging quality of coronary artery segments and the radiation dose were compared with t test.Results A total of 336 coronary artery segments were evaluated in group A and 412 segments were evaluated in group B.The imaging quality of coronary artery segments were scored.Excellent or good was achieved in 98.2%(330 of 336)artery segments in group A,and that was 98.1%(404 of 412)in group B.There was no statistical difference in imaging quality between the two groups(t=0.513,P=0.608).The average effective dose was(0.74±0.29)mSv in group A,whereas that was(3.67±1.37)mSv in group B.There was a significant difference between the two groups(t=-10.858,P=0.000).Conclusions The personalized low doses coronary artery scanning mode can substantially reduce radiation damage while preserving good imaging quality.