Impact of a vendor-specific motion-correction algorithm on image quality,interpretability, and diagnostic performance of daily routine coronary CT angiography: influence of heart rate on the effect of motion-correction

To investigate the impact of a vendor-specific motion-correction algorithm on morphological assessment of coronary arteries using coronary CT angiography (cCTA) and to evaluate the influence of heart rate (HR) on the motion-correction effect of this algorithm. Eighty-four patients (mean age 56.3 ± 11.4 years; 53 males) were divided into two groups with a HR of ≥65 and <65 bpm during cCTA, respectively. Images were assigned quality scores (graded 1–4) on coronary segments. Interpretability was defined as a grade >1. Catheter angiography was used to determine the diagnostic accuracy of cCTA for detecting significant stenosis (≥50 %). We compared the image quality, interpretability and diagnostic accuracy between the standard and motion-correction reconstructions in both groups. The motion-correction reconstructions showed significantly (p < 0.05) higher image quality in the proximal and middle right coronary artery (RCA) in the low HR group (57.2 ± 5.0 bpm; n = 51) and proximal-to-distal RCA, posterior descending artery, and proximal and distal left circumflex artery in the high HR group (71.1 ± 4.6 bpm; n = 33). The per-segment interpretability was significantly higher using motion-correction algorithm in the middle RCA in the low HR group and in the proximal and middle RCA in high HR group. Overall, the image quality and interpretability were improved using motion-correction reconstructions in both groups (p < 0.05). Motion-correction reconstruction demonstrated higher (p < 0.05) diagnostic accuracy in 25 patients from both groups. Use of the motion-correction algorithm improves the overall image quality and interpretability of cCTA in both groups. However, it may be more beneficial to the patients with a higher HR.     

Evaluation of postmortem MDCT and MDCT-angiography for the investigation of sudden cardiac death related to atherosclerotic coronary artery disease

The goal of this study was to evaluate the diagnostic value of postmortem multi-computed tomography (MDCT) and MDCT-angiography for sudden cardiac deaths related to ischemic heart disease. Twenty three cases were selected based on clinical history and the results of native MDCT, multiphase post-mortem CT-angiography and conventional autopsy were compared. Radiological examination showed calcification of coronary arteries in 78% of the cases, most of which were not detailed at autopsy. MDCT-angiography allowed better visualization of the coronary arteries than MDCT and permitted the evaluation of stenoses and occlusions. Of the 14 cases of coronary thrombosis detected at conventional autopsy, 11 were visible as stop of perfusion with CT-angiography and three were found to be partly perfused. One case had an old thrombosis with collateral circulation. One case had a coronary artery postmortem clot found with MDCT-angiography. Coronary artery calcifications are more easily detected and documented with radiological examination than with conventional autopsy. MDCT is of limited diagnostic value for ischemic heart disease. MDCT-angiography, when correctly interpreted, is a reasonable tool to view the morphology of coronary arteries, rule out significant coronary artery stenoses, identify occlusions and direct sampling for histological examination.     

The effect of calcium score on the diagnostic accuracy of coronary computed tomography angiography

The influence of coronary calcification on the diagnostic performance of coronary computed tomography angiography (CTA) remains controversial. This study attempts to assess the effect of coronary calcium score (CS) on the diagnostic accuracy of detecting coronary artery disease (CAD) using 64-row multidetector computed tomography (MDCT). Over a period of 2 years and 9 months, 113 symptomatic patients (37-87 year-old, mean 62.3, 92 males) underwent 64-row MDCT for coronary CS and CTA. All had conventional coronary angiography (CCA) within 90 (mean 9.6) days. Coronary CTA was evaluated with CCA as the gold standard. Of 113 patients, 18 patients had a CS of 0, 18 had scores between 1 and 100, 27 between 101 and 400, and 50 had scores >400. With respect to patient-based analysis, the accuracy of CTA was 90.3%, the sensitivity was 95%, and the specificity was 78.8%. Regarding patients with CS > 400, the accuracy, sensitivity, and specificity were 92, 95.6, and 60%, respectively. On vessel-based analysis, the specificity of CTA in different vessels with CS < [double bond] 400 and CS > 400 was as follows: right coronary artery 87.1% versus 87.5% (P = 0.924); left main artery 94.8% versus 66.7% (P = 0.173); left anterior descending artery 77.1% versus 27.3% (P = 0.001); and left circumflex artery 83.3% versus 42.8% (P = 0.011). A high CS does not significantly affect the diagnostic accuracy and sensitivity of CTA; however, it significantly decreases the specificity, particularly the left anterior descending and left circumflex arteries.     

Coronary CT Angiography for the Detection of Obstructive Coronary Artery Disease

Contemporary CT scanners offer high temporal and spatial resolution, permitting visualization of the rapidly moving heart and coronary arteries. The imaging of coronary artery lumen and detection of obstructive coronary artery disease is feasible with 64-detector-row and higher generation CT scanners. The diagnostic accuracy of coronary CT angiography as compared to invasive coronary angiography is good (sensitivity of 85%–100%, specificity of 85%–99%). The major strength of coronary CT angiography is the high negative predictive value (96% to 99%) that permits excluding significant coronary artery stenosis with high accuracy, when optimal image quality is achieved. Therefore, coronary CT angiography is an appropriate diagnostic test for a selected patient population with a low to intermediate probability of coronary artery disease.     

Myocardial ischemia detection with single-phase CT perfusion in symptomatic patients using high-pitch helical image acquisition technique

Coronary CT angiography (CCTA) suffers from a reduced diagnostic accuracy in patients with heavily calcified coronary arteries or prior myocardial revascularisation due to artefacts caused by calcifications and stent material. CT myocardial perfusion imaging (CTMPI) yields high potential for the detection of myocardial ischemia and might help to overcome the above mentioned limitations. We analysed CT single-phase perfusion using high-pitch helical image acquisition technique in patients with prior myocardial revascularisation. Thirty-six patients with an indication for invasive coronary angiography (28 with coronary stents, 2 with coronary artery bypass grafts and 6 with both) were included in this prospective study at two study sites. All patients were examined on a 2nd generation dual-source CT system. Stress CT images were obtained using a prospectively ECG-triggered single-phase high-pitch helical image acquisition technique. During stress the tracer for myocardial perfusion (MP) SPECT imaging was administered. Rest CT images were acquired using prospectively ECG-triggered sequential CT. MP-SPECT imaging and invasive coronary angiography served as standard of reference. In this heavily diseased patient cohort CCTA alone showed a low overall diagnostic accuracy for detection of hemodynamically relevant coronary artery stenosis of only 31% on a per-patient base and 60% on a per-vessel base. Combining CCTA and CTMPI allowed for a significantly higher overall diagnostic accuracy of 78% on a per-patient base and 92% on a per-vessel base (p?<?0.001). Mean radiation dose for stress CT scans was 0.9 mSv, mean radiation dose for rest CT scans was 5.0 mSv. In symptomatic patients with known coronary artery disease and prior myocardial revascularization combining CCTA and CTMPI showed significantly higher diagnostic accuracy in detection of hemodynamically significant coronary artery stenosis when compared to CCTA alone.     

The benefit of 64-MDCT prior to invasive coronary angiography in symptomatic post-CABG patients

Purpose The purpose of this study is to assess the diagnostic accuracy of 64-MDCT in symptomatic patients after CABG and to explore the advantages of the 64-MDCT results on the CAG procedure. Material and methods From December 2004 until August 2005, 34 post-CABG patients (29 men, mean age 63.5 ± 8.5 years) with 69 coronary artery bypass grafts were scanned on a 64-MDCT (Somatom Sensation 64, Siemens AG, Forchheim, Germany) prior to CAG. Angiograms and 64-MDCT images were evaluated for the existence of occlusions or significant stenosis (≥50% lumen reduction) in bypass grafts and native coronary arteries. Results 64-MDCT had a sensitivity, a specificity, and a diagnostic accuracy of 100% for occlusion detection. For stenosis detection, sensitivity was 100%, specificity 98.7% and diagnostic accuracy 98.7%. For detecting significant stenosis in native coronary arteries, 64-MDCT had a sensitivity of 80.0%, specificity of 90.8%, and a diagnostic accuracy of 87.1%. Seventeen patients (50.0%) did not need invasive treatment, 14 patients (41.2%) underwent a percutaneous coronary intervention (PCI), and 3 patients (8.8%) underwent surgery. Treatment advice based on 64-MDCT was correct in 88.2% of patients and when 64-MDCT results would have been known 58.8% of diagnostic CAG procedures could have been prevented. Conclusion In conclusion, 64-MDCT has a high diagnostic accuracy in detecting bypass graft stenosis and occlusions, and 64-MDCT based treatment advice was correct in 88.2% of patients.     

腔内CT密度值用于评估冠状动脉钙化及狭窄程度

目的观察冠状动脉CT成像(CCTA)中,根据冠状动脉钙化(CAC)近端与远端冠状动脉管腔CT值及校正后冠状动脉强化值(CCO)差值评估钙化部位管腔狭窄的准确度。方法对CCTA显示钙化的233支主要冠状动脉(左前降支、左回旋支和右冠状动脉),根据狭窄程度分为轻度狭窄组、中度狭窄组、重度狭窄组和完全闭塞组,比较各组CCO差值,分析以钙化近远端CCO差值评估冠状动脉狭窄的准确度。结果完全闭塞组CCO差值高于轻度狭窄组、中度狭窄组和重度狭窄组(P<0.001);重度狭窄组与中度狭窄组CCO差值差异无统计学意义(P>0.05);中度狭窄组和重度狭窄组CCO差值高于轻度狭窄组(P<0.001)。以钙化近远侧CCO差值0.086 9作为诊断界点,其诊断冠状动脉≥50%狭窄的敏感度、特异度、阳性预测值和阴性预测值分别为76.67%、75.47%、91.39%和48.78%;以0.2070作为诊断界点时,其诊断冠状动脉闭塞的敏感度、特异度、阳性预测值和阴性预测值分别为91.84%、79.89%、54.88%和97.35%。结论冠状动脉钙化近远端管腔CCO差值随狭窄程度加重而升高,以之作...     

多层螺旋CT冠状动脉造影图像质量的影响因素分析

目的探讨心率对多层螺旋CT冠状动脉造影图像质量的影响和最佳重建相位窗的选择。方法回顾性分析67例患者16层螺旋CT心电门控条件下冠状动脉造影图像。按心率分成≤60次/min、61～70次/min、71～80次/min和≥81次/min分成第1～4组,将冠状动脉图像按伪影多少及血管连续性分为1～3分,评价心率与图像质量的关系,并优选出各组显示冠状动脉的最佳相位窗。结果对每位患者4条冠状动脉(右冠状动脉、左冠状动脉主干、左前降支、左回旋及图像质量进行研究。心率≤60次/min,可用于分析的图像占86.7%;心率61～70次/min,可用于分析的图像占62.5%;心率71～80次/min,可用于分析的图像占40%;心率≥81次/min,可用于分析的图像占12.5%。第1、2组与第3、4组间冠脉总的检查成功率有统计学差异(P<0.05)。第1组所有冠状动脉节段以75%相位窗为最佳;第2组冠状动脉节段以75%为最佳相位窗占89.5%,第3组左右冠状动脉以45%和75%为最佳相位窗分别占45%和55%,第4组全部冠状动脉节段以45%为最佳相位窗。结论心率对多层螺旋CT冠状动脉造影图像质量有重要影响;心率70次/min以下冠状动脉最佳相位窗通常为75%,心率71次/min以上时,应该以30%～90%多相位重建。     

舌下含服硝酸甘油对螺旋CT冠状动脉造影中检测冠脉内径狭窄程度准确性影响的评价

目的评价64层螺旋CT(64-MSCT)冠状动脉造影中舌下含服硝酸甘油对检测冠脉内径狭窄程度准确性的影响。方法 2010年6月至2013年6月疑为冠心病的患者共72例行64-MSCT冠状动脉造影,分为给硝酸甘油及不给硝酸甘油两组,每组各36例,分别对两组患者右冠状动脉(RCA),左前降支(LAD),回旋支(LCA),左主干(LMA)近端内径进行测量,同时计算两组图像冠状动脉的13个节段显影的差异。结果硝酸甘油组的RCA、LM、LAD、LCX各支冠脉近端平均内径比非硝酸甘油组大,差异具有统计学意义(P0.05)。两组冠状动脉13个节段中,右冠状动脉、左主干、左前降支、左旋支可评价血管例数相同,后降支和左室后支、左前降支远段、第l对角支、钝圆支显示例数硝酸甘油组较多,但两者差异无统计学意义(P0.05);第2对角支及左旋支远段两组显示的例数有显著性差异(P0.05)。结论硝酸甘油对冠状动脉近端内径有显著的扩张作用,显示的节段数增多,可以提高64层螺旋CT冠状动脉造影成像质量,在一定程度上能提高冠状动脉内径狭窄程度的诊断的准确性。     

非刚性配准运动校正算法与双扇区重组对改善冠状动脉CTA图像质量的对比分析

目的一种基于非刚性配准的运动校正算法智能边缘修复技术(intelligent boundary registration,IBR)已应用于冠状动脉CTA成像。通过与双扇区重组图像质量的比较,评估IBR技术应用于冠状动脉成像的效果。方法本回顾性研究经医院伦理委员会批准,并获得患者的知情同意。收集本院行能谱CT冠状动脉CTA检查且平均心率为65次/min(范围58~75次/min)的70例可疑心肌缺血患者,在最佳心动时相进行双扇区图像重组(SSB2),即为SSB2组;在最佳心动时相进行单扇区图像重组,基于最佳单扇区重组执行IBR重组以生成IBR图像,即为IBR组。采用5分制评分(5=图像质量优秀;1=不能满足诊断要求),评价指标包括:整体图像质量、血管的评估(连续性、有无运动伪影、血管的边缘模糊与否)。由两位心血管放射学医师通过双盲和独立观察比较,对SSB2和IBR处理后的图像分别进行冠状动脉整体水平和冠状动脉节段评分。结果共分析了70位患者冠状动脉的984个节段。两位医师的评分结果具有良好的一致性(k0.81),SSB2组和IBR组的平均评分分别为(4.02±1.28)和(4.45±1.01),两者间的差异具有统计学差异(Z=-9.22,P0.01)。在基于冠状动脉节段的分析中,可接受的图像质量不低于3分的百分比分别为88.3%和91.2%,具有统计学差异(X~2=5.68,P0.05);可接受的图像质量不低于4分的百分比为分别为73.3%和88.5%,具有统计学差异(X~2=6.47,P0.05)。在重组的血管中不可评估的节段IBR组明显低于SSB2组,差异具有统计学意义(4.2%与9.5%,X~2=12.13,P0.01)。结论能谱CT冠状动脉IBR技术可以提高冠状动脉CTA的图像质量,减少阶梯状伪影。     

静息心率增高对老年冠心病患者病情的影响

目的：探讨老年冠心病（CHD）患者的静息心率（RHR）与其病情的关系。方法：选择169例老年CHD患者（CHD组）同时进行冠状动脉造影及射血分数（EF）和RHR的测定，选择同期体检健康者96例为正常对照组。结果：CHD组RHR（76．1±10．5）次／min高于正常对照组（68．4±4．2）次／min（P〈0．01）。多支血管狭窄组RHR（82．5±11．5）次／min高于单支血管狭窄组（71．1±8．4）次／min（P〈0．05），也高于2支血管狭窄组（73．9±6．6）次／min（P〈0．05）。冠状动脉狭窄程度≥90％者RHR（79．4±10．4）次／min高于〈90％者（73．0±9．7）次／min（P〈0．05）。老年CHD患者中，EF值〈50％者RHR（85．8±12．2）次／min明显高于EF值≥50％者（73．1±7．8）次／min（P〈0．05）。结论：RHR与cHD的病情及预后有一定关系。可作为病情及预后的评估指标。[著者文摘]     

多层螺旋CT在冠心病的临床应用价值及存在问题

目的在病例非选择性的基础上,将多层螺旋CT冠状动脉血管造影(CTA)与侵入性冠状动脉造影(ICA)相比,评估其准确性及敏感性,并分析其伪影产生的原因以及解决方法。方法对45名可疑冠心病患者在7~10d先后予以CTA及ICA检查,将二者相比。结果对45名患者从节段水平分析其敏感性、特异性、阳性预测值、阴性预测值为:85.0%,99.1%,93.1%,98.0%;患者水平分别为:84.8%,75.0%,90.3%,64.2%。结论CTA诊断准确性高,尤其表现在节段水平对于阴性预测值判断,从患者水平分析,其诊断价值下降,显示对于高度危险患者,常规行CTA检查,并不能从中获益。由于患者自身或扫描的原因会出现影响图像诊断的伪影,对这些伪影的成因及特点进行分析有助于提高CTA的成功率及避免假阳性的诊断。     

Methods for quantification of coronary artery calcifications with electron beam and conventional CT and pushing the spiral CT envelope: new cardiac applications

Detection of coronary artery calcifications with slice by slice prospective ECG triggering is feasible with electron beam CT as well as with single and multi-row-detector CT (MDCT). The radiation exposure to the patient to obtain comparable image quality is similar for all three modalities utilizing this prospective acquisition technique.Alternatively, coronary screening can be performed by MDCT with retrospective EKG spiral gating. Radiation exposure to the patient with this technique is significantly higher than with prospective triggering. Nevertheless, acquisition of the entire volume of the heart with retrospective gating holds promise to improve reproducibility of coronary calcium measurements, especially in patients with a low amount of coronary calcium and in patients with atrial fibrillation.If retrospective gating is used for CT angiography (CTA) with MDCT this allows to use thin slices (1.25 mm) and to perform the acquisition within one breath hold period (app. 35 s). This technique is currently limited by the temporal resolution per slice (250 ms). In order to achieve diagnostic image quality the heart rate of the patient thus needs to be sufficiently low. Therefore, in cases with heart rates significantly higher than 70 beats/min betablocker have to be administered for patient preparation as long as there are no contraindications for such a regimen.Because of low image noise and high spatial resolution CTA with MDCT is able to display the entire extent of atherosclerosis allowing to visualize calcified as well as non-calcified plaques of the coronary arteries. Under clinical conditions CTA has the potential to accurately rule out or diagnose significant coronary stenoses of the proximal and mid-segments of the coronary artery tree when compared to conventional selective coronary angiography.     

Prospectively versus retrospectively ECG-gated 256-slice coronary CT angiography: image quality and radiation dose over expanded heart rates

To compare image quality and radiation dose estimates for coronary computed tomography angiography (CCTA) obtained with a prospectively gated transaxial (PGT) CT technique and a retrospectively gated helical (RGH) CT technique using a 256-slice multidetector CT (MDCT) scanner and establish an upper limit of heart rate to achieve reliable diagnostic image quality using PGT. 200 patients (135 males, 65 females) with suspected coronary artery disease (CAD) underwent CCTA on a 256-slice MDCT scanner. The PGT patients were enrolled prospectively from January to June, 2009. For each PGT patient, we found the paired ones in retrospective-gating patients database and randomly selected one patient in these match cases and built up the RGH group. Image quality for all coronary segments was assessed and compared between the two groups using a 4-point scale (1: non-diagnostic; 4: excellent). Effective radiation doses were also compared. The average heart rate ± standard deviation (HR ± SD) between the two groups was not significantly different (PGT: 64.6 ± 12.9 bpm, range 45–97 bpm; RGH: 66.7 ± 10.9 bpm, range 48–97 bpm, P = 0.22). A receiver-operating characteristic (ROC) analysis determined a cutoff HR of 75 bpm up to which diagnostic image quality could be achieved using the PGT technique (P < 0.001). There were no significant differences in assessable coronary segments between the two groups for HR ≤ 75 bpm (PGT: 99.9% [961 of 962 segments]; RGH: 99.8% [1038 of 1040 segments]; P = 1.0). At HR > 75 bpm, the performance of the PGT technique was affected, resulting in a moderate reduction of percentage assessable coronary segments using this approach (PGT: 95.5% [323 of 338 segments]; RGH: 98.5% [261 of 265 segments]; P = 0.04). The mean estimated effective radiation dose for the PGT group was 3.0 ± 0.7 mSv, representing reduction of 73% compared to that of the RGH group (11.1 ± 1.6 mSv) (P < 0.001). Prospectively-gated axial coronary computed tomography using a 256-slice multidetector CT scanner with a 270 ms tube rotation time enables a significant reduction in effective radiation dose while simultaneously providing image quality comparable to the retrospectively gated helical technique. Our experience demonstrates the applicability of this technique over a wider range of heart rates (up to 75 bpm) than previously reported.     

Computed Tomographic Angiography of the Coronary Arteries: Techniques and Applications

Computed tomographic coronary angiography (CT-CA) is a direct but minimally invasive method of visualizing coronary arteries. Multidetector-row computed tomography (MDCT) is currently the CT modality most commonly used for coronary artery imaging. MDCT has been successfully used to detect stenoses in coronary arteries and coronary artery bypass grafts and to assess congenital coronary anomalies. Patients should not undergo CT-CA with MDCT if they have an irregular heart rhythm, a heart rate greater than 70 beats/min, and contraindications to pharmacologic agents for heart rate control, or if they have severe coronary artery disease or are likely to require revascularization.     

Visual assessment of coronary artery stenosis with electrocardiographically-gated multislice computed tomography

BACKGROUND: With faster image acquisition times and thinner slice widths, multislice detector computed tomography (MSCT) allows visualization of human coronary arteries. Significantly improved image quality, with high resolution and new software for three-dimensional post-processing, has made noninvasive examination of the cavities within human body possible. OBJECTIVE: The aims of this study are to evaluate the diagnostic accuracy of ECG-gated MSCT for the detection of significant coronary artery stenosis and occlusions. METHODS: In 25 patients (19 male and 6 female aged 65+/-9 years) with suspected obstructive coronary artery disease, ECG-gated MSCT angiography was performed with an 8-slice MSCT scanner. Visual coronary arteries were simulated in three coronary arteries. Conventional coronary angiographies were performed in all patients. And coronary lesions in MSCT were estimated by two observers, who did not know the results of the coronary angiography. RESULTS: Current MSCT allows visual coronary artery with good image quality. The overall sensitivity for diagnosing significant coronary stenosis were 75.0%, the specificity was 95.6%. The positive and negative predictive values were 84.9 and 92.2%, respectively. The accuracy of MSCT for detecting coronary stenosis is the highest in the left main tranck and left anterior descending coronary artery, and lowest in the circumflex coronary artery. CONCLUSION: MSCT was feasible for the detection of coronary artery stenosis.     

Coronary artery fistula in a patient with coronary artery disease: evaluation by coronary angiography and multidetector computed tomography

A 54-year-old man with acute miyocardial infarction was successfully treated with coronary artery stenting. Coronary angiography is the preferred diagnostic method for imaging the coronary arteries, but coronary artery fistulas origin and course may not be apparent. New tomographic cardiovascular imaging tests such as, multidetector computed tomography (MDCT) can be used to precise delineation of coronary fistulas. An erratum to this article can be found at     

Coronary to pulmonary artery fistula: morphologic features at multidetector CT

The objective of this study is to evaluate the incidence and morphologic features of coronary-pulmonary artery fistulas (CPAF) by multidetector computed tomography (MDCT). From 2006 to 2008, 5,372 patients underwent ECG-gated cardiac CT scans using 64-slice MDCT at our institute. Among them, 17 cases of CPAF were detected (M:F = 14:3, mean age = 63 years). Chief complaints of patients were chest pain (n = 12), abnormal cardiac test (n = 3), known coronary artery disease (n = 1), and known CPAF (n = 1). We retrospectively analyzed the morphologic features of CPAF, such as origin vessels, draining site, fistula size, and aneurysmal sac. Five cases underwent coronary angiography (CAG) and correlated with MDCT findings. Incidence of CPAF was 0.32% by MDCT. The origin of CPAF was the left coronary artery in five (29.4%), the right coronary artery in two (11.8%) and both coronary arteries in ten cases (58.8%). In regard to the diameter of the detected fistula, the diameter of the largest vessel excluding aneurysm was variable from less than 2 to 5.7 mm. Five patients (29.4%) had a fistula that was shown as one vessel that could be traced, one patient (5.9%) was shown as two vessels, and eleven patients (64.7%) were shown as innumerable multiple vessel networks. Five cases were associated with aneurysm (29.4%). Fistulas were located primarily in the left anterolateral aspect of the pulmonary trunk (82.3%) and mostly the drainage site was the left lateral side of the pulmonary trunk (82.3%). CAG was performed in five cases and revealed identical findings to MDCT. In conclusion, coronary-pulmonary artery fistula is more frequently found than anticipated on MDCT. CPAF is supplied by either single or both coronary arteries and drains to the left side of the pulmonary trunk. It is typically located in the anterolateral aspect of the pulmonary trunk. Sometimes CPAF is associated with aneurysms.     

Low-dose coronary computed tomography angiography using prospective ECG-triggering compared to invasive coronary angiography

To assess the diagnostic accuracy of prospective ECG-triggering 64-slice multidetector computed tomography (MDCT) coronary angiography for evaluation of coronary artery disease (CAD). Forty-two patients (31 males, 11 females, mean age 64 years) underwent cardiac CT and invasive coronary angiography (ICA). Patients with a heart rate of <65 beats/min with stable heart rhythm were included in the study sample. We used a prospective ECG-triggering protocol. Luminal narrowing over 50% was considered to be significant according to a modified 17-segment AHA model, using invasive coronary angiography (ICA) as the standard of reference. The mean radiation dose was 3.5 mSv ± 0.3 (range, 3.3–4.2 mSv), and 542 of 549 segments (98.7%) in the 42 patients were diagnostic. In contrast, 119 of 542 segments (22%) were diagnosed as significant by ICA. The sensitivity, specificity, accuracy, PPV and NPV were 95.0, 96.2, 96, 85.8 and 98.8%, respectively. False positive results were affected by densely calcified plaques, whereas false negatives were caused by motion artifact with poor vessel attenuation at the distal segments or near the bifurcation area of the coronary arteries. Prospective ECG-triggering MDCT is a useful method for evaluating CAD in patients with a lower heart rate with low radiation dose.     

Impact of an acute coronary syndrome pathway in achieving target heart rate and utilization of evidence-based doses of Beta-blockers

Beta-blockers remain a cornerstone of therapy in the management of acute coronary syndrome (ACS). The 2007 American College of Cardiology/American Heart Association unstable angina/non-ST elevation myocardial infarction guideline revisions recommend a target heart rate (HR) of 50-60 beats per minute (bpm). Despite improved trends toward utilization of beta-blockers therapy, beta-blockers continue to be underdosed. Guideline-based tools have been shown to improve adherence to evidence-based therapy in patients with ACS. Implementation of a standardized ACS pathway would lead to titration of beta-blockers to recommended dosages with improved HRs in eligible patients. The ACS clinical protocol was implemented at the University of Toledo Medical Center in May 2007. A retrospective study of 516 patients admitted during a comparable 6-month period, before and after the institution of the protocol, was conducted. The preprotocol and protocol group included 237 and 279 patients, respectively. Patient information extracted from the medical records included age, gender, HR on admission, blood pressure on admission, duration of hospital stay, preadmission use of beta-blocker, type of beta-blocker and dosage, discharge beta-blocker and dosage, peak troponin levels, and therapeutic intervention. A target HR of less than 60 bpm was achieved in 19% of the protocol group, as compared with 6% in the preprotocol group (P < 0.001). The protocol group had a significantly lower mean discharge HR than the preprotocol group (67 vs. 74 bpm; P < 0.001). The mean discharge dose of metoprolol in the protocol group was noted to be significantly higher (118 vs. 80 mg/d; P < 0.001). The institution of an ACS clinical pathway led to utilization of beta-blockers in significantly higher dosages, resulting in improved HR control and increased attainment of target HR.