心率对64层螺旋CT冠状动脉成像图像质量的影响

目的:评价心率对64层螺旋CT冠状动脉成像图像质量的影响.方法:采用GE Light speed 64层螺旋VCT,以心脏扫描模式对心脏动态体模进行扫描.心脏动态体模由3个部分组成:动力部分、解剖结构模拟部分和控制部分.心脏动态体模的心率设置为40、45、50、55、60、65、70、75、80、85、90、95、100、105、110和115次/min,心律齐.以球管转速0.35 s对不同心率下的心脏动态体模进行冠状动脉成像扫描.所有扫描数据在R-R间期90%时相分别进行单扇区和多扇区重建.重建数据传至工作站后处理成像.后处理方法采用VR、MPR重组模式.分别对重建图像进行评分.结果:①心率与图像质量呈负相关(P＜0.01);随着心率的增加,图像质量评分呈下降趋势;②在同一条件下多扇区重建算法较单扇区重建算法提高了图像质量评分.结论:采用心脏动态体模评价心率对64层螺旋CT冠状动脉成像图像质量的影响,对临床研究和应用有着重要价值.     

房颤患者的64层CTCA:平均心率对图像质量和最佳重建期相的影响

目的:评价房颤患者64层螺旋CT冠状动脉成像中平均心率对最佳图像重建时相和图像质量的影响.方法:58例房颤患者行64层螺旋CT冠状动脉成像,扫描前均未服用美托洛尔.血管图像质量分为好、中等和差.分析平均心率和患者总体图像质量之间的相关性,采用判别分析法计算获得总体图像质量为好和中等的平均心率阈值和最佳重建时相在收缩末期的平均心率阈值.结果:平均心率和患者总体图像质量之间呈负相关(r=-0.43,P=0.001);患者总体图像质量为好和中等的平均心率阈值分别为80次/min和95次/min;最佳重建时相在收缩末期的平均心率阈值为85次/min.结论:控制患者平均心率在一定阈值以下并结合舒张中期蕈建.能保证房颤患者64层螺旋CT冠状动脉成像获得较高的图像质量.     

320排CT冠状动脉成像心率(律)对图像质量和辐射剂量的影响

目的:探讨不同心率(律)的条件下,320排容积CT冠状动脉血管成像的图像质量和辐射剂量。方法:将259例临床怀疑或确诊冠状动脉疾病的患者分为两组:窦性心律组(S组)220例;心律失常组(N组)39例。其中S组分为:A组79例,心率<65bpm;B组102例,65≤心率<80bpm;C组39例,心率≥80bpm。扫描完成后选用最佳的时相,对冠状动脉进行容积重组(VR)、多平面重组(MPR)、曲面重组(CPR)。按照4分法将图像质量分类并统计分析,比较各组冠状动脉血管段的优良率、可评价性;记录各组的辐射剂量,比较辐射剂量的差异。结果:S组与N组之间冠状动脉血管段优良率和可评价性的差异均无统计学意义。所有病例共有9段冠状动脉不可评价。所有病例平均辐射剂量为(9.49±6.54)mSv;S组和N组平均辐射剂量分别为(8.45±5.7)mSv、(15.36±7.79)mSv,两组之间辐射剂量差异具有统计学意义(t=-5.29,P=0.000)。窦性心律各组辐射剂量差异具有统计学意义(2=126.43,P=0.000)。结论:320排CT能较好适应心率(律)变化,保证诊断图像质量,对于心率<65bpm以下的窦性心律患者辐射剂量降低显著。     

320排容积CT冠状动脉血管成像前瞻性心电门控最佳重建时相的初步研究

目的 探讨320排容积CT(320-DVCT)冠状动脉血管成像前瞻性心电门控最佳重建时相,初步评价其对图像质量、曝光剂量及诊断准确性的影响.方法 对77例行DVCT心功能扫描的患者[平均扫描心率(70±13)次/min( bpm),范围46～ 102 bpm]做回顾性心电门控扫描,分析最佳重建时相与心率的关系.利用不同心率最佳重建时相作为前瞻性心电门控扫描曝光时相,对53例需接受冠状动脉导管造影的患者[平均扫描心率(75±11) bpm,范围57～114 bpm]同时行冠状动脉CT成像,评价曝光时相对图像质量、曝光剂量及诊断准确性的影响.图像质量评分随机区组多样本比较采用Friedman检验,双变量统计行直线回归分析及Spearman相关分析.结果 随着心率的增加,收缩期比例逐渐增高(r=0.78,P＜0.01).收缩期与舒张期最佳重建图像质量随着心率的增加明显下降(r分别为0.38、0.82,P均＜0.01).根据回归方程分析,最佳重建时相按心率分组如下:心率＜ 70 bpm,65％～80％;70～80 bpm,70％ ～85％;81 ～90 bpm,70％～90％;＞90 bpm,35％ ～ 50％.利用上述最佳重建时相行前瞻性心电门控扫描结果表明,前瞻性心电门控扫描较回顾性心电门控扫描明显降低辐射剂量[分别为(6.1±3.8)和(12.4±7.0) mSv,t=6.5,P＜0.01],对诊断准确性并无明显影响.但是随着心率的增加,前瞻性心电门控扫描辐射剂量仍会明显增加(r=0.64,P＜0.01).结论DVCT可在更宽心率范围内应用前瞻性心电门控扫描技术对冠状动脉进行准确诊断;但在高心率条件下需要多个心动周期扫描,辐射剂量明显增加,建议尽可能降低患者心率以降低辐射剂量.     

Multi-detector row CT coronary angiography: influence of reconstruction technique and heart rate on image quality

PURPOSE: To prospectively evaluate to what extent image quality in 16-detector row computed tomographic (CT) coronary angiography is a function of the heart rate and the image reconstruction technique used. MATERIALS AND METHODS: A total of 70 patients (49 men, 21 women; mean age, 59.1 years +/- 5.8 [standard deviation]) consecutively underwent multi-detector row CT coronary angiography; 49 patients additionally underwent coronary angiography. Image reconstruction was based on both relative and absolute timing. A total of 20 equidistant relative and absolute image reconstructed intervals were assessed by applying a four-step grading scale. Cluster and discrimination analysis, Spearman correlation analysis, and Wilcoxon and chi2 tests were used for statistical analysis. Institutional review board approval and written informed consent were obtained. RESULTS: Though significantly (P < .001) better image quality was observed for image reconstruction based on absolute timing and in patients with lower heart rates, influence on diagnostic accuracy was not significant. Irrespective of the reconstruction technique used, best image quality was observed in patients with a low heart rate for middiastolic reconstruction intervals (starting points: 61% of R-R interval [range, 40%-75%] and 599.3 msec after R [range, 450-840 msec]) and in patients with a high heart rate for end-systolic or early-diastolic intervals (starting points: 27.3% of R-R interval [range, 10%-45%] and 202.3 msec after R [range, 82-336 msec]). With regard to the vessel section and reconstruction technique, cutoff heart rates of the intervals were 64.0-68.5 beats per minute. Patients with stenoses of more than 50% were identified with 86% sensitivity and specificity, and there was no significant difference between relative and absolute timing (P = .99). CONCLUSION: In multi-detector row CT coronary angiography, image quality depends on the choice of a suited reconstruction interval. In patients with high heart rates, the best image quality can be obtained with end-systolic and early-diastolic intervals; in patients with low heart rates, the best results are achieved with middiastolic intervals.     

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%.     

Interpretability of coronary CT angiography performed with a novel whole-heart coverage high-definition CT scanner in 300 consecutive patients with coronary artery bypass grafts

AimsCoronary CT angiography (CCTA) is an accurate non-invasive tool for the evaluation of coronary artery bypass graft (CABG). However, inability to sustain a long breath-hold, high heart rate (HR) and atrial fibrillation may affect image quality. Moreover, radiation exposure is still a matter of some concern. A scanner combining 0.23-mm spatial resolution, new iterative reconstruction and fast gantry rotation time has been recently introduced in the clinical field. The aims of our study were to evaluate interpretability, radiation exposure and diagnostic accuracy of CCTA performed with the latest generation of cardiac-CT scanners compared to invasive coronary angiography (ICA) in the assessment of bypass grafts, and non-grafted and post-anastomotic native coronary arteries.Methods and resultsWe prospectively enrolled 300 patients undergoing clinically indicated CCTA with a 16-cm z-axis coverage, 256-detector rows, and 0.28-sec gantry rotation time scanner. Coronary artery and graft interpretability, image quality and effective dose (ED) were assessed in all patients and diagnostic accuracy was evaluated in a subgroup of 100 patients who underwent ICA.Mean HR during the scan was 69.6 ± 10.8. Sinus rhythm was present in 118 patients with HR < 75 bpm and in 112 patients with HR ≥ 75 bpm, while 70 patients had atrial fibrillation. CABG interpretability was 100%. Compared to ICA, CCTA was able to correctly detecting occlusions or significant stenoses of all CABG segments. Overall interpretability of native coronary segments was 95.6%. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of coronary arteries were 98.3%, 97.4%, 93.1%, 99.3% and 96.5%, respectively. The diagnostic accuracy in a patient based analysis was 95.2%. Mean ED was 3.14 ± 1.7 mSv.ConclusionsThe novel whole-heart coverage CT scanner allows to evaluating CABG and native coronary arteries with excellent interpretability and low radiation exposure even in the presence of unfavorable heart rhythm.     

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。     

320排CT单心跳冠状动脉成像的图像质量及辐射剂量分析

目的:探讨320排CT低心率患者单心跳冠状动脉血管成像的图像质量及辐射剂量.方法:将241例临床可疑或确诊冠状动脉疾病的患者分为三组:A组122例,心率＜65bpm;B组62例,65≤心率＜80bpm;C组57例,心率≥80bpm.扫描完成后选用最佳的时相,对冠状动脉进行容积重组(VR)、多平面重组(MPR)、曲面重组(CPR).按照4分法将图像质量分类并统计分析,用卡方检验比较冠状动脉血管段的优良率、可评价比例的差异;记录各组的辐射剂量,用秩和检验比较辐射剂量的差异.结果:A、B、C三组冠状动脉血管段优良率差异有统计学意义(x2=87.46,P＜0.05),可评价比例差异无统计学意义(x2 =3.99,P＞0.05).所有病例共有5段冠状动脉不可评价.A、B、C三组的平均辐射剂量分别为(3.79±2.32) mSv、(11.60±5.05)mSv、(16.52±6.36) mSv,其差异具有统计学意义(x2=149.11,P＜0.05).A组与B组、A组与C组、B组与C组辐射剂量两两比较差异均有统计学意义(Z值分别为-11.39、-8.47、-4.32,P值均＜0.017).结论:320排CT冠状动脉成像对于心率＜65bpm的患者可提供高质量的图像,且显著降低辐射剂量.     

Noninvasive imaging of the coronary arteries using a 64-row multidetector CT scanner: initial clinical experience and radiation dose concerns

PURPOSE: We present our initial clinical experience with a recently introduced 64-detector computed tomography (64-MDCT) scanner that makes use of a periodic motion of the focal spot in the longitudinal direction (z-flying focal spot), which enables it to reach a final spatial resolution of 0.4 x 0.4 x 0.4 mm(3) and a temporal resolution of 83 ms. MATERIALS AND METHODS: A total of 114 patients (108 men, six women; age range 36-77 years, mean 63.1 years) underwent retrospective electrocardiogram (ECG)-gated examination of the coronary arteries using a 64-MDCT scanner (Somatom Sensation 64, Siemens Medical Solutions, Germany). Acquisition parameters were the following: collimation 64 x 0.6 mm, 800 quality reference milliampere second (mAs), 120 kVp, 0.33-s gantry rotation time and pitch 0.2. Images were acquired in all cases after i.v. administration of 80 ml of contrast agent (Iomeron 400 mgI/dl, Bracco, Italy) + 30 ml of saline at 4 /s and delay time determined using a bolus triggering technique. Oral betablockers were administered to patients with heart rate (HR) >75 bpm. To reduce radiation exposure, an automatic exposure control system was applied in all cases to adapt tube current to patient size and anatomic shape (CARE Dose 4D, Siemens Medical Solutions, Germany). The optimal temporal window for raw data reconstruction was chosen from an initial preview of images reconstructed with different phase settings (range 0%-95% RR interval with 5% gap) at a selected anatomical level in the mid part of the right coronary artery. CT dose index volume and effective dose were quantified in all patients using dedicated software. RESULTS: Mean HR recorded during image acquisition was 65.6+/-19.2 bmp (range: 44-96 bmp), and beta-blockers were administered to 16/114 patients (14.0%). Technical adequacy was achieved in all patients but two (2/114; 1.7%). In patients with HR <60 bmp, the best reconstruction intervals were identified in the end-systolic (30%-35% of the RR interval) and end-diastolic (60%-65% of the RR interval) phases; with faster HR (>80 bmp), high image quality was observed in end-systole (30%-35% of the RR interval). Mean CT dose index (CTDI) volume was 36.53+/-8.30 mGy per patient. In comparison with a conventional examination with fixed mAs, the use of the CARE Dose 4D system provided a 33.3% CTDI volume reduction (p<0.001). Mean effective dose was 9.5+/-3.4 millisievert (mSv) per patient (range 7.1-17.7). CONCLUSIONS: The 64-MDCT scanner diagnostic performance for coronary CT angiography is further improved with better spatial and temporal resolution and faster scan times; besides, initial clinical results are promising. The use of dose-reducing acquisition techniques is mandatory to limit radiation exposure to the patient.     

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。     

Noninvasive coronary angiography with 16-detector row CT: effect of heart rate

PURPOSE: To evaluate the effect of heart rate on the quality of coronary angiograms obtained with 16-detector row computed tomography (CT) by using temporally enhanced three-dimensional (3D) approaches. MATERIALS AND METHODS: The local ethics committee approved the study, and informed consent was obtained from all patients. Fifty patients underwent coronary CT angiography (heart rate range, 45-103 beats per minute). Raw data from helical CT and electrocardiography (ECG) were saved in a combined data set. Retrospectively ECG-gated images were reconstructed at preselected phases (50% and 80%) of the cardiac cycle. A 3D voxel-based approach with cardiac phase weighting was used for reconstruction. Testing for correlation between heart rate, cardiac phase reconstruction window, and image quality was performed with Kruskal-Wallis analysis. Image quality (freedom from cardiac motion-related artifacts) was referenced against findings at conventional angiography in a secondary evaluation step. Regression analysis was performed to calculate heart rate thresholds for future beta-blocker application. RESULTS: A significant negative correlation was observed between heart rate and image quality (r = 0.80, P < .001). Motion artifact-free images were available for 44 (88%) patients and were achieved consistently at a heart rate of 80 or fewer beats per minute (n = 39). Best image quality was achieved at 75 or fewer beats per minute. Segmental analysis revealed that 97% of arterial segments (diameter > or = 1.5 mm according to conventional angiography) were assessable at 80 or fewer beats per minute. Premature ventricular contractions and rate-contained arrhythmia did not impede diagnostic assessment of the coronary arteries in 10 (83%) of the 12 patients affected. CONCLUSION: Motion-free coronary angiograms can be obtained consistently with 16-detector row CT scanners and adaptive multicyclic reconstruction algorithms in patients with heart rates of less than 80 beats per minute.     

64层螺旋CT冠状动脉成像图像质量的相关影响因素分析(心脏体模模拟实验)

目的采用心脏动态体模，对64层螺旋CT冠状动脉成像图像质量的相关影响因素进行分析。方法采用GE Light speed64层螺旋CT，以心脏扫描的模式对心脏动态体模进行扫描。心脏动态体模由3部分组成：动力部分、解剖结构模拟部分和控制部分组成。心率设置为40、45、50、55、60、65、70、75、80、85、90、95、100、105、110和115次／min，X线管转速设置为每转0．35、0．40和0．45S，分别对不同心率下的心脏动态体模进行冠状动脉成像扫描。所有扫描数据在R-R间期90％时相分别进行单扇区和多扇区重组。重组数据传至AW4．2工作站后处理成像。后处理方法采用容积重组（VR）、多平面重组（MPR）模式。分别对不同重组图像进行评分。统计学处理采用多元线性回归模型。结果（1）心率对图像质量的影响有统计学意义（P〈0．01），随着心率的增加，图像质量评分呈下降趋势。多元线性回归分析显示心率每增加1次，图像质量评分平均减低0．046；（2）重组算法对图像质量的影响有统计学意义（P〈0．01），在同一条件下多扇区重组算法较单扇区重组算法能增加图像质量评分0．5。（3）X线管转速在0．35、0．40和0．45S下对图像质量的影响无统计学意义（P〉0，05），在40-115次／min心率时的重组图像，得到的最高评分时X线管转速分别为0．35和0．45S。（4）心率、重组算法与图像质量间具有多元线性回归关系（标准化回归系数分别为-0．824和0．194）。结论心脏动态体模评价64层螺旋CT冠状动脉成像图像质量的影响因素，能够为其临床应用和基础研究提供帮助。     

Image quality, motion artifacts, and reconstruction timing of 64-slice coronary computed tomography angiography with 0.33-second rotation speed

OBJECTIVES: We sought to evaluate the impact of patients' heart rate (HR) on coronary CTA image quality (IQ) and motion artifacts using a 64-slice scanner with 0.33/360 degrees rotation. MATERIALS AND METHODS: Coronary CTA data sets of 32 patients (HR 65 bpm to 75 bpm, n = 7) examined on a 64-slice scanner (Sensation 64, Siemens Medical Solutions, Forchheim, Germany) with 0.33s/360 degrees gantry rotation speed were analyzed. All patients had suspicion of coronary artery disease. Data acquisition was performed using 64 x 0.6-mm collimation, and contrast enhancement was provided by injection of 80 mL of iopromide (5 mL/s + NaCl). Images were reconstructed throughout the RR interval using half-scan and dual-segment reconstruction. IQ was rated by 2 observers using a 3-point scale from excellent (1) to nondiagnostic (3) for coronary segments. Quality was correlated to the HR, time point of optimal IQ analyzed, and the benefit of dual-segment reconstruction evaluated. RESULTS: Overall mean IQ was 1.31 +/- 0.32 for all HR, with IQ being 1.08 +/- 0.12 for HR 65 bpm 75 bpm (P = 0.0003). Dual-segment reconstruction did not significantly improve IQ in any HR group (P = NS). Mean IQ was significantly better for LAD than for RCA (P < 0.0001) and LCX (P < 0.01). A total of 3.5% (11/318) of coronary artery segments were rated nondiagnostic by at least one reader based on motion artifacts. Although in HR < 65 bpm, the best IQ was predominately in diastole (93%), in HR > 75 bpm, the best IQ shifted to systole in most cases (86%). CONCLUSIONS: Temporal resolution at 0.33-second rotation allows for diagnostic IQ within a wide range of HR using half-scan reconstruction. With increasing HR the time point of best IQ shifts from mid-diastole to systole.     

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.     

Image quality and reconstruction intervals of dual-source CT coronary angiography: recommendations for ECG-pulsing windowing

PURPOSE: To evaluate reconstruction intervals and image quality in dual-source computed tomography (DSCT) coronary angiography for optimal placement of the ECG-pulsing window. MATERIALS AND METHODS: DSCT coronary angiography was performed in 60 patients. Thirteen datasets were reconstructed in 5% increments from 20-80%. Two readers independently assessed image quality of each segment in each percentage-interval, using scores ranging from 1 (no motion artifacts) to 4 (nonevaluable). RESULTS: Mean heart rate (HR) was 69.0 +/- 18.9 beats per minute (bpm) (range, 35-117 bpm). Diagnostic image quality (scores 1-3) was found in 97.8% of all segments (763 of 780). The 70% RR-interval provided best image quality in all patients and all HRs. The narrowest reconstruction window providing diagnostic image quality was 60-70% for HR <60 bpm, 60-80% for 60-70 bpm, 55-80% for 70-80 bpm, and 30-80% for HR >80 bpm. CONCLUSIONS: DSCT coronary angiography provides best image quality for various HRs at 70%. The ECG-pulsing window can be adapted according to the HR while maintaining diagnostic image quality.     

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.     

Influence of heart rate in the selection of the optimal reconstruction window in routine clinical multislice coronary angiography

PURPOSE: The aim of our study was to assess the influence of heart rate on the selection of the optimal reconstruction window with 40-slice multidetector-row computed tomography (40-MDCT) coronary angiography. MATERIALS AND METHODS: We studied 170 patients (114 men, age 60+/-11.3 years) with suspected or known coronary artery disease with 40-MDCT coronary angiography. Patients [mean heart rate (HR) 62.9+/-9.3 bpm, range 42-94 bpm] were clustered in two groups (group A: HR 65 bpm). Multiphase reconstruction data sets were obtained with a retrospective electrocardiogram (ECG)-gated 40-MDCT coronary angiography scan from 0% to 95% every 5% of the R-R interval. Two radiologists in consensus evaluated the best data sets for diagnostic purposes. RESULTS: In group A, the optimal reconstruction windows were at 70% (55/110, 71/110 and 69/110 for the right coronary artery, left anterior descending and the left circumflex, respectively) and 75% (26/110, 28/110 and 28/110, respectively) of the R-R interval. In group B, a wide range of reconstruction windows were employed, both in the end-systolic phase at 40% (32/60, 18/60 and 17/60, for the right coronary artery, left anterior descending and circumflex, respectively) and diastolic phases at 70% (12/60, 22/60 and 19/60, respectively). Six scans were excluded due to severe respiratory artefacts. CONCLUSIONS: Optimal position of the image reconstruction window relative to the cardiac cycle is significantly influenced by the heart rate during scanning. Diastolic reconstruction phases often allowed an optimal assessment in group A. Reconstruction phases from 30% to 45% are advisable for higher heart rates.     

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。     

心率对16层螺旋CT冠状动脉造影图像质量的影响

目的探讨心率对16层螺旋CT冠状动脉造影图像质量的影响。方法80例健康体检者行16层螺旋CT回顾性心电门控条件下冠状动脉造影。每位患者的4条冠状动脉分支(左冠状动脉主干、左前降支、左回旋支、右冠状动脉)分别用于图像质量分析。结果心率≤65次/m in有89.3%(100/112支)的图像可用于诊断;心率66~80次/m in有81.1%(198/244支)的图像可用于诊断;心率>80次/m in有64.3%(36/56支)的图像可用于诊断;心律不齐或前后波动>5次/m in有25%(8/32支)的血管可用于诊断。结论MSCTCA图像质量受心率影响,并与之呈负相关。