Dual-source-Computertomographie des Herzens

In a newly developed dual-source computed tomography system (DSCT) the relation of heart rate and image quality and the possible advantages of the system’s superior temporal resolution in the evaluation of left ventricular parameters as compared to results of cardiac magnetic resonance imaging (MRI) were assessed. Coronary CT angiography was performed using a DSCT (Somatom Defintion, Siemens Medical Solutions, Forchheim, Germany) in 21 patients (mean age 62±8; 15 male, 6 female). Image quality of the coronary arteries, the heart valves, and the left ventricular myocardium was assessed using a three-point grading scale. Ten of these patients also underwent cardiac MRI for the assessment of left ventricular function, using a SSFP (steady-state free precession) sequence. Left ventricular ejection fractions (LV-EF), the end-systolic volumes (ESV), and the end-diastolic volumes (EDV) were measured employing MRI and DSCT datasets. The image quality ratings for the coronary arteries at the optimal reconstruction interval were diagnostic even in patients with high heart rates (1.42±0.49). Analysis of global LV function using DSCT quantified from CTA datasets showed a good correlation with results of cardiac MRI [EF: r=0.75 (p=0.01); ESV: r=0.72 (p=0.19); EDV: r=0.71 (p=0.02)]. The dual-source CT system offers robust image quality of the coronary arteries, independent of the heart rate, and provides combined diagnostic imaging of coronary arteries, the heart valves, the myocardium, and the global left ventricular function.     

Dual-source cardiac CT imaging with improved temporal resolution: Impact on image quality and analysis of left ventricular function

In a newly developed dual-source computed tomography system (DSCT) the relation of heart rate and image quality and the possible advantages of the system's superior temporal resolution in the evaluation of left ventricular parameters as compared to results of cardiac magnetic resonance imaging (MRI) were assessed. Coronary CT angiography was performed using a DSCT (Somatom Defintion, Siemens Medical Solutions, Forchheim, Germany) in 21 patients (mean age 62+/-8; 15 male, 6 female). Image quality of the coronary arteries, the heart valves, and the left ventricular myocardium was assessed using a three-point grading scale. Ten of these patients also underwent cardiac MRI for the assessment of left ventricular function, using a SSFP (steady-state free precession) sequence. Left ventricular ejection fractions (LV-EF), the end-systolic volumes (ESV), and the end-diastolic volumes (EDV) were measured employing MRI and DSCT datasets. The image quality ratings for the coronary arteries at the optimal reconstruction interval were diagnostic even in patients with high heart rates (1.42+/-0.49). Analysis of global LV function using DSCT quantified from CTA datasets showed a good correlation with results of cardiac MRI [EF: r=0.75 (p=0.01); ESV: r=0.72 (p=0.19); EDV: r=0.71 (p=0.02)]. The dual-source CT system offers robust image quality of the coronary arteries, independent of the heart rate, and provides combined diagnostic imaging of coronary arteries, the heart valves, the myocardium, and the global left ventricular function.     

Quantitative parameters to compare image quality of non-invasive coronary angiography with 16-slice, 64-slice and dual-source computed tomography

Multi-slice computed tomography (MSCT) is a non-invasive modality to visualize coronary arteries with an overall good image quality. Improved spatial and temporal resolution of 64-slice and dual-source computed tomography (DSCT) scanners are supposed to have a positive impact on diagnostic accuracy and image quality. However, quantitative parameters to compare image quality of 16-slice, 64-slice MSCT and DSCT are missing. A total of 256 CT examinations were evaluated (Siemens, Sensation 16: n = 90; Siemens Sensation 64: n = 91; Siemens Definition: n = 75). Mean Hounsfield units (HU) were measured in the cavum of the left ventricle (LV), the ascending aorta (Ao), the left ventricular myocardium (My) and the proximal part of the left main (LM), the left anterior descending artery (LAD), the right coronary artery (RCA) and the circumflex artery (CX). Moreover, the ratio of intraluminal attenuation (HU) to myocardial attenuation was assessed for all coronary arteries. Clinical data [body mass index (BMI), gender, heart rate] were accessible for all patients. Mean attenuation (CA) of the coronary arteries was significantly higher for DSCT in comparison to 64- and 16-slice MSCT within the RCA [347 ± 13 vs. 254 ± 14 (64-MSCT) vs. 233 ± 11 (16-MSCT) HU], LM (362 ± 11/275 ± 12/262 ± 9), LAD (332 ± 17/248 ± 19/219 ± 14) and LCX (310 ± 12/210 ± 13/221 ± 10, all p < 0.05), whereas there was no significant difference between DSCT and 64-MSCT for the LV, the Ao and My. Heart rate had a significant impact on CA ratio in 16-slice and 64-slice CT only (p < 0.05). BMI had no impact on the CA ratio in DSCT only (p < 0.001). Improved spatial and temporal resolution of dual-source CT is associated with better opacification of the coronary arteries and a better contrast with the myocardium, which is independent of heart rate. In comparison to MSCT, opacification of the coronary arteries at DSCT is not affected by BMI. The main advantage of DSCT lies with the heart rate independency, which might have a positive impact on the diagnostic accuracy. Christof Burgstahler and Anja Reimann contributed equally to this work     

Dual-source cardiac computed tomography: image quality and dose considerations

Computed tomography (CT) imaging of the heart, most prominently coronary CT angiography, is currently subject to intense interest and is increasingly incorporated into clinical decision-making. In spite of tremendous progress in CT technology over the past decade, the limited temporal resolution has remained one of the most severe problems, especially for cardiac imaging. The novel design concept of dual-source CT (DSCT) allows for an effective scan time of 83 ms independent of heart rate. While large trials are still missing, initial studies have shown improved image quality, especially for visualizing the coronary arteries and detecting coronary artery stenoses. Further investigations have shown that routine beta blockade to lower the heart rate is not necessary to reliably achieve diagnostic image quality. Other applications that may particularly benefit from increased temporal resolution are the analysis of ventricular function and of the cardiac valves. Dose issues which are of interest for cardiac CT in general are discussed in some detail, including a quantitative analysis of dose values and three-dimensional dose distributions. Various strategies to lower radiation exposure are available today, and DSCT offers specific potential for this.     

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。     

Image quality on dual-source computed-tomographic coronary angiography

Multi-detector CT reliably permits visualization of coronary arteries, but due to the occurrence of motion artefacts at heart rates >65 bpm caused by a temporal resolution of 165 ms, its utilisation has so far been limited to patients with a preferably low heart rate. We investigated the assessment of image quality on computed tomography of coronary arteries in a large series of patients without additional heart rate control using dual-source computed tomography (DSCT). DSCT (Siemens Somatom Definition, 83-ms temporal resolution) was performed in 165 consecutive patients (mean age 64 +/- 11.4 years) after injection of 60-80 ml of contrast. Data sets were reconstructed in 5% intervals of the cardiac cycle and evaluated by two readers in consensus concerning evaluability of the coronary arteries and presence of motion and beam-hardening artefacts using the AHA 16-segment coronary model. Mean heart rate during CT was 65 +/- 10.5 bpm; visualisation without artefacts was possible in 98.7% of 2,541 coronary segments. Only two segments were considered unevaluable due to cardiac motion; 30 segments were unassessable due to poor signal-to-noise ratio or coronary calcifications (both n = 15). Data reconstruction at 65-70% of the cardiac cycle provided for the best image quality. For heart rates >85 bpm, a systolic reconstruction at 45% revealed satisfactory results. Compared with earlier CT generations, DSCT provides for non-invasive coronary angiography with diagnostic image quality even at heart rates >65 bpm and thus may broaden the spectrum of patients that can be investigated non-invasively.     

Optimal image reconstruction intervals for non-invasive coronary angiography with 64-slice CT

The reconstruction intervals providing best image quality for non-invasive coronary angiography with 64-slice computed tomography (CT) were evaluated. Contrast-enhanced, retrospectively electrocardiography (ECG)-gated 64-slice CT coronary angiography was performed in 80 patients (47 male, 33 female; mean age 62.1±10.6 years). Thirteen data sets were reconstructed in 5% increments from 20 to 80% of the R-R interval. Depending on the average heart rate during scanning, patients were grouped as <65 bpm (n=49) and ≥65 bpm (n=31). Two blinded and independent readers assessed the image quality of each coronary segment with a diameter ≥1.5 mm using the following scores: 1, no motion artifacts; 2, minor artifacts; 3, moderate artifacts; 4, severe artifacts; and 5, not evaluative. The average heart rate was 63.3±13.1 bpm (range 38–102). Acceptable image quality (scores 1–3) was achieved in 99.1% of all coronary segments (1,162/1,172; mean image quality score 1.55±0.77) in the best reconstruction interval. Best image quality was found at 60% and 65% of the R-R interval for all patients and for each heart rate subgroup, whereas motion artifacts occurred significantly more often (P<0.01) at other reconstruction intervals. At heart rates <65 bpm, acceptable image quality was found in all coronary segments at 60%. At heart rates ≥65 bpm, the whole coronary artery tree could be visualized with acceptable image quality in 87% (27/31) of the patients at 60%, while ten segments in four patients were rated as non-diagnostic (scores 4–5) at any reconstruction interval. In conclusion, 64-slice CT coronary angiography provides best overall image quality in mid-diastole. At heart rates <65 bpm, diagnostic image quality of all coronary segments can be obtained at a single reconstruction interval of 60%.     

Visualization of anomalous coronary arteries on dual-source computed tomography

The purpose of this study is to assess the capability of dual-source computed tomography (DSCT) in evaluating coronary artery anomalies. Early detection and evaluation of coronary artery anomalies is essential because of their potential association with myocardial ischemia and sudden death. In 16 patients (12 men, mean age 50 ± 14 years), anomalous coronary arteries were detected on contrast-enhanced DSCT in a patient cohort of 230 individuals (incidence of 7%). Six different types of anomalies were diagnosed (three fistula, four anomalies of the circumflex artery, four anomalous right coronary arteries, three anomalies of the left coronary artery, one absent left main coronary artery, and one left coronary artery arising from the pulmonary trunk). Of the 16 patients, 10 also underwent conventional coronary angiography (CAG). Retrospective evaluation of the CAGs by an experienced interventional cardiologist resulted in a precise diagnosis in 50% of patients. With DSCT, sufficient image quality and exact visualization of the aberrant anatomy were achieved in all patients. Therefore, DSCT seems to be an accurate diagnostic tool for examining the precise origin, course, and shape of aberrant coronary arteries.     

Accuracy of dual-source CT coronary angiography: first experience in a high pre-test probability population without heart rate control

The aim of this study was to assess the diagnostic accuracy of dual-source computed tomography (DSCT) for evaluation of coronary artery disease (CAD) in a population with extensive coronary calcifications without heart rate control. Thirty patients (24 male, 6 female, mean age 63.1±11.3 years) with a high pre-test probability of CAD underwent DSCT coronary angiography and invasive coronary angiography (ICA) within 14±9 days. No beta-blockers were administered prior to the scan. Two readers independently assessed image quality of all coronary segments with a diameter ≥1.5 mm using a four-point score (1: excellent to 4: not assessable) and qualitatively assessed significant stenoses as narrowing of the luminal diameter >50%. Causes of false-positive (FP) and false-negative (FN) ratings were assigned to calcifications or motion artifacts. ICA was considered the standard of reference. Mean body mass index was 28.3±3.9 kg/m² (range 22.4–36.3 kg/m²), mean heart rate during CT was 70.3±14.2 bpm (range 47–102 bpm), and mean Agatston score was 821±904 (range 0–3,110). Image quality was diagnostic (scores 1–3) in 98.6% (414/420) of segments (mean image quality score 1.68±0.75); six segments in three patients were considered not assessable (1.4%). DSCT correctly identified 54 of 56 significant coronary stenoses. Severe calcifications accounted for false ratings in nine segments (eight FP/one FN) and motion artifacts in two segments (one FP/one FN). Overall sensitivity, specificity, positive and negative predictive value for evaluating CAD were 96.4, 97.5, 85.7, and 99.4%, respectively. First experience indicates that DSCT coronary angiography provides high diagnostic accuracy for assessment of CAD in a high pre-test probability population with extensive coronary calcifications and without heart rate control.     

双源CT自适应前瞻性心电门控冠状动脉成像技术的初步应用

目的：初步探讨双源CT前瞻性心电门控冠状动脉成像的图像质量和辐射剂量。方法：对50例临床怀疑冠心病的受检者进行双源CT自适应前瞻性门控冠状动脉成像,检查前均未服用琥珀酸美托洛尔。图像质量分4级,依照美国心脏病协会（AHA）冠状动脉分段标准分别评价各个冠状动脉节段的图像质量,分别计算每例的有效辐射剂量（ED）。结果：50例受检者平均体重指数（BM I）为（25.00±2.58）kg/m2,扫描时平均心率（71.13±9.63）次/min,平均有效辐射剂量（3.31±1.08）mSv,显示了94.76%能满足诊断要求的冠状动脉节段,图像质量优秀占79.49%。结论：双源CT自适应前瞻性心电门控冠状动脉成像对于无严重心律失常的受检者都可得到满足诊断要求的图像,辐射剂量低,具有广阔的应用前景。     

Dual-source CT coronary imaging in heart transplant recipients: image quality and optimal reconstruction interval

The image quality and optimal reconstruction interval for coronary arteries in heart transplant recipients undergoing non-invasive dual-source computed tomography (DSCT) coronary angiography was evaluated. Twenty consecutive heart transplant recipients who underwent DSCT coronary angiography were included (19 male, one female; mean age 63.1 +/- 10.7 years). Data sets were reconstructed in 5% steps from 30% to 80% of the R-R interval. Two blinded independent observers assessed the image quality of each coronary segments using a five-point scale (from 0 = not evaluative to 4 = excellent quality). A total of 289 coronary segments in 20 heart transplant recipients were evaluated. Mean heart rate during the scan was 89.1 +/- 10.4 bpm. At the best reconstruction interval, diagnostic image quality (score >/=2) was obtained in 93.4% of the coronary segments (270/289) with a mean image quality score of 3.04 +/- 0.63. Systolic reconstruction intervals provided better image quality scores than diastolic reconstruction intervals (overall mean quality scores obtained with the systolic and diastolic reconstructions 3.03 +/- 1.06 and 2.73 +/- 1.11, respectively; P < 0.001). Different systolic reconstruction intervals (35%, 40%, 45% of RR interval) did not yield to significant differences in image quality scores for the coronary segments (P = 0.74). Reconstructions obtained at the systolic phase of the cardiac cycle allowed excellent diagnostic image quality coronary angiograms in heart transplant recipients undergoing DSCT coronary angiography.     

64层探测器CT冠状动脉成像依据不同心率的最佳重建方案

目的:探讨64层螺旋CT冠状动脉成像不同心率下冠状动脉各节段血管的最佳重建时相。方法:对61例患者行64层螺旋CT冠状动脉成像,扫描后原始数据分别按R-R间期30%、35%、40%、45%、50%、60%、70%、75%的相位进行后处理重组,按扫描期间平均心率分组,Ⅰ组30例,心率70次/min;Ⅱ组31例,心率≥70次/min。分析不同心率组不同R-R时相对各支冠状动脉血管的显示情况。结果:Ⅰ组的所有的冠状动脉节段可以在单一的75%相位上获得最佳图像质量;Ⅱ组的所有冠状动脉可以在单一的45%或40%的相位上获得最佳图像质量,多时相重建并不能显著提高图像质量。结论:随着64层螺旋CT时间分辨率的充分发展,所有冠状动脉节段能在一个重建时相得到有诊断价值的图像,多时相重建并不能显著提高图像质量。     

Minidose技术在双源CT心脏扫描中的初步应用

目的：探讨Minidose技术在双源CT（DSCT）冠状动脉成像及左心室功能分析中的应用价值。方法：45例临床怀疑为冠状动脉心脏病的患者行DSCT冠状动脉成像和超声心动图左心室功能检查。DSCT采用序列扫描模式,总扫描时间窗35％～95％R—R间期,其中40％～70％R-R间期时为全电流输出,数据用于冠状动脉重建,其余间期使用全电流的20％输出,数据用于左心室功能分析。依据美国心脏协会冠状动脉分法,将冠脉图像分为16段,并采用4级法对每段图像质量进行评估。将DSCT检查时测量的左心室射血分数值（LVEF）,并与超声心动图所测得的LVEF值为对照进行统计学分析。结果：40例患者顺利完成DscT冠状动脉成像及超声心动图左心室功能分析。共评价冠状动脉525段,其中可用于诊断的节段占97．53％（512／525）,平均辐射剂量为（3．75±0．89）mSv。DSCT与超声心动图所测得的LVEF值差异无统计学意义（t=-1．61,P=0．12〉0．05）,且两者相关性好（r=0．68）。结论：Minidose技术可以用于DSCT冠状动脉成像兼顾左心室功能分析的“一站式”扫描,冠状动脉图像质量较好,左心室功能分析结果可靠,平均辐射剂量低。     

64层螺旋CT冠状动脉图像质量控制研究:最佳重组时相与心率关系

目的量化评估64层螺旋CT冠状动脉各分支不同重组时相图像质量,探讨冠状动脉CT成像最佳重组时相与心率关系。资料与方法102例患者均采用64层螺旋CT回顾性心电门控冠状动脉成像,男68例,女34例,平均年龄(58.1±9.7)岁,平均心率(66.4±11.5)次/min。心率<65次/min(n=43)为Ⅰ组,65～75次/min(n=34)为Ⅱ组,>75次/min(n=25)为Ⅲ组,每例患者的4支冠状动脉(左主干、左前降支、左回旋支、右冠状动脉)共分为12个节段用于图像质量分析。扫描原始数据以间隔5%在20%～80%时相分别回顾性重组冠状动脉图像,采用横断位、曲面重组、容积再现等方法对图像质量综合评分。结果Ⅰ组60%、65%和70%为最佳时相,Ⅱ组60%、65%时相为最佳时相,Ⅲ组右冠状动脉较优时相为35%、40%,左冠状动脉较优时相为60%、65%。结论心率和重组时相的选择是决定冠状动脉图像质量的重要因素。平均心率≤75次/min,冠状动脉各分支图像质量在心脏运动的舒张中期(60%、65%)最佳;>75次/min时,左右冠状动脉分别进行重组能明显提高冠状动脉的成像质量。     

冠状动脉瘘的双源CT诊断

目的:探讨双源CT(DSCT)冠状动脉成像对冠状动脉瘘的诊断价值.方法:对1000例患者行DSCT冠状动脉增强扫描,分析其断层图像,结合最大密度投影(MIP)、曲面重组(CPR)、多平面重组(MPR)和容积再现(VR)等方法观察冠状动脉的走行及心内外机构.结果:11例患者有冠状动脉瘘,其中右冠状动脉主干-肺动脉瘘5例,...     

Value of knowledge-based iterative model reconstruction in low-kV 256-slice coronary CT angiography

BackgroundMost current iterative reconstruction algorithms for CT imaging are a mixture of iterative reconstruction and filtered back projection. The value of “fully” iterative reconstruction in coronary CT angiography remains poorly understood.ObjectiveWe aimed to assess the value of the knowledge-based iterative model reconstruction (IMR) algorithm on the qualitative and quantitative image quality at 256-slice cardiac CT.MethodsWe enrolled 21 patients (mean age: 69 ± 11 years) who underwent retrospectively ECG gated coronary CT anhgiography at 100 kVp tube voltage. Images were reconstructed with the filtered back projection (FBP), hybrid iterative reconstruction (IR), and IMR algorithms. CT attenuation and the contrast-to-noise ratio (CNR) of the coronary arteries were calculated. With the use of a 4-point scale, 2 reviewers visually evaluated the coronary arteries and cardiac structures.ResultsThe mean CT attenuation of the proximal coronary arteries was 369.3 ± 73.6 HU, 363.9 ± 75.3 HU, and 363.3 ± 74.5 HU, respectively, for FBP, hybrid IR, and IMR and was not significantly different. The image noise of the proximal coronary arteries was significantly lower with IMR (11.3 ± 2.8 HU) than FBP (51.9 ± 12.9 HU) and hybrid IR (23.2 ± 5.2 HU). The mean CNR of the proximal coronary arteries was 9.4 ± 2.4, 20.2 ± 4.7, and 41.8 ± 9.5 with FBP, hybrid IR and IMR, respectively; it was significantly higher with IMR. The best subjective image quality for coronary vessels was obtained with IMR (proximal vessels: FBP, 2.6 ± 0.5; hybrid IR, 3.4 ± 0.5; IMR, 3.8 ± 0.4; distal vessels: FBP, 2.3 ± 0.5; hybrid IR. 3.1 ± 0.5; IMR, 3.7 ± 0.5). IMR also yielded the best visualization for cardiac systems, that is myocardium and heart valves.ConclusionThe novel knowledge-based IMR algorithm yields significantly improved CNR and better subjective image quality of coronary vessels and cardiac systems with reliable CT number measurements for cardiac CT imaging.     

双源CT冠状动脉成像的图像质量及重组时相与心率的关系

目的 探讨双源CT冠状动脉成像的图像质量和重组时相与心率的关系.方法 对95例临床可疑冠心病患者进行双源CT增强扫描,检查前均不使用β受体阻滞剂控制心率.按扫描时心率分为3组:低心率组(≤70 次/min)26例,中心率组(71～90 次/min)37例,高心率组(t≥91 次/min)32例.利用回顾性心电门控重建出10%～100% R-R时相的图像,分析不同R-R时相冠状动脉的图像质量情况及其与心率的关系.结果 低、中、高心率3组图像质量评分分别为(1.08±0.27)、(1.32±0.58)、(1.47±0.61)分,低心率和中心率组图像质量评分差异无统计学意义(P＞0.05),低心率组图像质量评分显著优于高心率组(P＜0.05),中心率组和高心率组图像质量评分差异无统计学意义(P＞0.05).只有1.4%(19/1386)的冠状动脉节段不可评价.74例患者(77.9%)可在单一重组时相获得冠状动脉各段最佳图像质量.低心率组23例(88.5%)最佳重组时相在舒张中晚期;高心率组27例(84.4%)的最佳重组时相前移至舒张早期和收缩末期.结论 双源CT能够在相当宽的心率范围内提供优良的图像质量;多数患者可在单一时相获得各支冠状动脉最佳质量图像,随着心率的增快最佳重组时相从舒张中晚期前移至舒张早期和收缩末期.     

Dual-source computed tomography in patients with acute chest pain: feasibility and image quality

The aim of this study was to determine the feasibility and image quality of dual-source computed tomography angiography (DSCTA) in patients with acute chest pain for the assessment of the lung, thoracic aorta, and for pulmonary and coronary arteries. Sixty consecutive patients (32 female, 28 male, mean age 58.1±16.3 years) with acute chest pain underwent contrast-enhanced electrocardiography-gated DSCTA without prior beta-blocker administration. Vessel attenuation of different thoracic vascular territories was measured, and image quality was semi-quantitatively analyzed by two independent readers. Image quality of the thoracic aorta was diagnostic in all 60 patients, image quality of pulmonary arteries was diagnostic in 59, and image quality of coronary arteries was diagnostic in 58 patients. Pairwise intraindividual comparisons of attenuation values were small and ranged between 1±6 HU comparing right and left coronary artery and 56±9 HU comparing the pulmonary trunk and left ventricle. Mean attenuation was 291±65 HU in the ascending aorta, 334±93 HU in the pulmonary trunk, and 285±66 HU and 268±67 HU in the right and left coronary artery, respectively. DSCTA is feasible and provides diagnostic image quality of the thoracic aorta, pulmonary and coronary arteries in patients with acute chest pain.     

双源CT诊断冠脉狭窄的价值—与冠状动脉造影对照分析

目的:探讨双源CT冠脉成像评价冠脉中度及中度以上狭窄的准确性及可行性。方法:入选60例临床高度怀疑或已确诊冠脉疾病的患者,行双源CT扫描,扫描过程中患者心率平稳,未出现心率不齐及心律失常。患者于1周内行经皮选择性冠状动脉造影,并以冠状动脉造影作为标准,从冠脉节段及冠脉分支角度分别评价双源CT诊断冠脉中度及中度以上狭窄的准确性、敏感性、特异性、阳性预测率及阴性预测率。结果:以冠脉节段为基础分析,双源CT诊断冠脉明显狭窄的敏感性、特异性、阳性预测率、阴性预测率、准确性分别为81.14%、97.57%、85.34%、96.74%、95.13%;以冠脉分支为基础分析,双源CT诊断冠脉明显狭窄的敏感性、特异性、阳性预测率、阴性预测率、准确性分别为84.21%、93.79%、89.88%、90.06%、90.0%。双源CT与选择性冠脉造影对发现冠脉狭窄节段及检查冠脉分支病变的能力进行卡方检验,χ2分别0.625、1.041;P0.05,双源CT与选择性冠脉造影比较在发现冠脉明显狭窄差异上无统计学意义。结论:双源CT在诊断冠脉明显狭窄时有很高的准确性,可作为无创性评价冠脉狭窄及疾病的手段。     

平均心率、心率波动和心率变异性对双源CT冠状动脉影像质量影响的研究

目的：评价平均心率、心率波动和心率变异性对双源CT冠状动脉影像质量的影响。方法：100例患者进行了双源CT冠状动脉血管成像。原始数据经多期相重建优选出最佳收缩期和舒张期影像,以4分法评定系统进行影像质量评价。利用Pearson相关分析评价平均心率、心率波动和心率变异性对冠状动脉的影像质量的影响,对有相关性者行进一步分析。结果：100例患者,共纳入分析的血管为299支,296支血管可满足影像评价（99％）。平均心率、心率波动和心率变异性对总的冠状动脉影像质量没有影响,仅平均心率对舒张期冠状动脉影像质量有负影响（P〉0．05）,尤其对右冠状动脉的影响更明显,70bpm以上时影像质量即下降,80bpm以上时影像质量甚至难以满足评价。结论：平均心率、心率波动和心率变异性对双源cr冠状动脉总的影像质量没有影响,但平均心率对舒张期冠状动脉的影像质量有负影响,对右冠状动脉的影响更大,当心率大于80bpm时,利用舒张期的数据难以获得RCA满意的影像质量,应该利用最佳收缩期的数据进行影像重组。