Impact of scan quality on the diagnostic performance of CCTA,SPECT, and PET for diagnosing myocardial ischemia defined by fractional flow reserve

BackgroundScan quality can have a significant effect on the diagnostic performance of non-invasive imaging techniques. However, the extent of its influence has scarcely been investigated in a head-to-head manner.MethodsTwo-hundred and eight patients underwent CCTA, SPECT, and PET prior to invasive fractional flow reserve measurements. Scan quality was classified as either good, moderate, or poor.ResultsDistribution of good, moderate, and poor quality scans was; CCTA; 66%, 22%, 13%; SPECT; 52%, 38%, 9%; PET; 86%, 13%, 1%. Good quality CCTA scans possessed a higher specificity (75% vs. 31%, p = 0.001), positive predictive value (PPV, 71% vs. 51%, p = 0.050), and accuracy (80% vs. 60%, p = 0.009) compared to moderate quality scans, while sensitivity (94%) and negative predictive value (NPV, 88%) were similar to moderate and poor quality scans. Sensitivity (76%), NPV (84%), and accuracy (85%) of good quality SPECT scans was superior to those of moderate (41% p = 0.001, 56% p = 0.010, 70% p = 0.010) and poor quality (30% p = 0.003, 65% p = 0.069, 63% p = 0.038). Specificity (92%) and PPV (87%) of good quality SPECT scans did not differ from scans of diminished quality. Good quality PET scans exhibited high sensitivity (84%), specificity (86%), NPV (88%), PPV (81%) and accuracy (85%), which was comparable to scans of lesser quality. Good quality CCTA, SPECT, and PET scans demonstrated a similar diagnostic accuracy (p = 0.247).ConclusionDiagnostic performance of CCTA, and SPECT is hampered by scan quality, while the diagnostic value of PET is not affected. Good quality CCTA, SPECT, and PET scans possess a high diagnostic accuracy.     

FFR CT的技术原理、注意事项和结果解释

有创性血流储备分数（FFR）是评价冠状动脉血管生理功能的金标准。FFR_CT是基于冠状动脉CT血管成像的影像后处理技术,可用于评估特异性缺血病灶。大量证据支持FFR_CT有很高的诊断准确性,该技术正在从实验研究应用到临床人群。如何在日常临床工作中优化FFR_CT技术以实现病人利益最大化引起了广泛关注。总结FFR_CT的基本原理,对其注意事项和结果解读进行分析,以利于指导FFR_CT的临床应用。      

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.     

心电编辑技术在改善双源CT冠状动脉成像质量中的应用

目的探讨心电编辑技术在改善双源CT冠状动脉成像中的作用。方法对316例接受双源冠状动脉造影的患者图像进行回顾性分析,其中20例因在扫描过程中出现心律不齐而导致伪影并进行心电编辑。冠状动脉图像质量分为5级,Ⅰ～Ⅲ级为合格图像,Ⅳ和Ⅴ级为不合格图像。结果进行心电编辑者包括窦性心律不齐11例,室性早搏6例,心电起搏心率2例,房颤1例;其中Ⅲ级图像3例,Ⅲ级以下图像17例。经心电编辑处理后,17例Ⅲ级以下图像中16例达到Ⅲ级（94％）。结论心电编辑技术为改善心律不齐或心律失常患者双源CT冠脉成像质量提供了一项有效可靠的手段。     

Plaque progression: Where,why, and how fast? A review of what we have learned from the analysis of patient data from the PARADIGM registry

Ischemic heart disease is the most common cause of mortality worldwide. The pathophysiology of myocardial infarction relates to temporal changes of atherosclerotic plaque culminating in plaque rupture, erosion or hemorrhage and the subsequent thrombotic response. Coronary computed tomographic angiography (CCTA) provides the ability to visualize and quantify plaque, and plaque progression can be measured on a per-patient basis by comparing findings of serial CCTA. The Progression of AtheRosclerotic PlAque DetermIned by Computed TomoGraphic Angiography IMaging (PARADIGM) registry was established with the objective of identifying patterns of plaque progression in a large population. The registry comprises over 2000 patients with multiple CCTA scans performed at least two years apart. Unlike previous CCTA registries, a semi-automated plaque quantification technique permitting detailed analysis of plaque progression was performed on all patients with interpretable studies. Since the registry was established, 19 peer-reviewed publications were identified, and all are reviewed and summarized in this article.     

2型糖尿病患者冠状动脉钙化的超高速CT分析

探讨2型糖尿病患者冠状动脉钙化的情况。材料和方法：运用超高速CT对50例2型糖尿病患者和24例无糖尿病对照者进行了心脏总的冠状动脉及各分支钙化程度的检查,由电子计算机自动分析仪计数并成像。结果：（1）86％的糖尿病患者75％的对照者存在不同程度的冠状动脉钙化。（2）糖尿病及对照组间、钙化部分数及各冠状动脉分支钙化分数间、各冠状动脉分支钙化不同组合间差别均无统计学差异,糖尿病和非糖尿病患者左冠状动脉主干钙化分数均较左前降支少。（3）糖尿病及对照组中钙化总分数异常升高者（＞300）约占三分之一左右。（4）糖尿病 高龄组（年龄≥66岁）钙化部分数和左前降支、左旋支钙化分数高于年龄＜65岁组。（5）糖尿病患者钙化总分数与年龄、糖化血红蛋白、胆固醇水平呈显著正相关。结论：年龄、高血糖、高胆固醇血症,为影响糖尿病患者冠状动脉钙化的因素。     

双源CT血管造影评价冠状动脉狭窄的临床价值

目的:评价双源CT定量诊断冠状动脉狭窄的准确性及临床价值。方法:对30例临床拟诊冠心病患者分别进行双源CT和传统冠状动脉造影检查,并将双源CT判定冠状动脉狭窄程度与冠脉造影结果进行对比分析。结果:30例共计450冠脉节段,双源CT均获得满意的评价图像(3例进行心电编辑)。双源CT判定轻度狭窄38个节段,中度狭窄23个节段,重度狭窄36个节段;与冠状动脉造影结果对比,双源CT诊断冠脉狭窄的敏感性、特异性和准确性分别为94.12%、95.34%和95.11%。结论:与冠状动脉造影对比,双源CT在定量诊断冠脉狭窄方面具有较高的敏感性和特异性,可为临床诊断冠心病提供一项准确可靠的无创手段。     

Non-invasive evaluation of coronary artery stent patency with retrospectively ECG-gated 64-slice CT angiography

The aim of our study has been to evaluate the ability of 64-slice computed tomographic angiography (CTA) to assess coronary artery stent patency, relative to selective coronary angiography (SCA). Fifty-five consecutive patients (age range 45–80 years) with 97 previously implanted coronary artery stents underwent 64-slice CTA. The 55 patients comprised 40 subjects (group A) who were referred for follow-up SCA at a mean interval of 9.6 months after stent positioning, and 15 subjects (group B) in whom SCA was clinically indicated. Stent evaluation was performed independently by two blinded readers in terms of image quality and presence of in-stent restenosis (ISR; lumen obstruction of ≥50%). SCA was performed in 41/55 patients; 14 patients refused to undergo SCA after the 64-slice CTA exam. A total of 88 stents in 74 segments were analyzed. Twenty-one of the 74 stented segments were of poor image quality and were not considered for further analysis. Sixty-four-slice CTA detected 12/16 ISR (sensitivity: 75%) and ruled out ISR in 32/37 cases (specificity: 86%). Sixty-four-slice CTA is a valuable modality for follow-up of coronary artery stent patency only in selected patients. Appropriate candidates for follow-up 64-slice CTA should be established based on stent diameter, stent material and type as well as HR and heart rhythm. However, given the number of non-assessable segments, further work would appear necessary before 64-slice CTA can be considered a suitable procedure for broad clinical application in the evaluation of coronary artery stent patency.     

Plaque volume,composition, and fraction versus ischemia and outcomes in patients with coronary artery disease

BackgroundThe various plaque components have been associated with ischemia and outcomes in patients with coronary artery disease (CAD). The main goal of this analysis was to test the hypothesis that, at patient level, the fraction of non-calcified plaque volume (PV) of total PV is associated with ischemia and outcomes in patients with CAD. This ratio could be a simple and clinically useful parameter, if predicting outcomes.MethodsConsecutive patients with suspected CAD undergoing coronary computed tomography angiography with selective positron emission tomography perfusion imaging were selected. Plaque components were quantitatively analyzed at patient level. The fraction of various plaque components were expressed as percentage of total PV and examined among patients with non-obstructive CAD, suspected stenosis with normal perfusion, and those with reduced myocardial perfusion. Clinical outcomes included all-cause mortality and myocardial infarction.ResultsIn total, 494 patients (age 63 ​± ​9 years, 55% male) were included. Total PV and all plaque components were significantly larger in patients with reduced myocardial perfusion compared to patients with normal perfusion and those with non-obstructive CAD. During follow-up 35 events occurred. Patients with any plaque component ​≥ ​median showed worse outcomes (log-rank p ​< ​0.001 for all). In addition, low-attenuation plaque ​≥ ​median was associated with worse outcomes independent of total PV (adjusted HR: 2.754, 95% CI: 1.022–7.0419, p ​= ​0.045). The fractions of the various plaque components were not associated with outcomes.ConclusionLarger total PV or any plaque component at patient level are associated with abnormal myocardial perfusion and adverse events. The various plaque components as fraction of total PV lack additional prognostic value.     

Importance of measurement site on assessment of lesion-specific ischemia and diagnostic performance by coronary computed tomography Angiography-Derived Fractional Flow Reserve

BackgroundValues of fractional flow reserve (FFR_CT) by coronary computed tomography angiography (CTA) decline from the ostium to the terminal vessel, irrespective of stenosis severity. The purpose of this study is to determine if the site of measurement of FFR_CT impacts assessment of ischemia and its diagnostic performance relative to invasive FFR (FFR_INV).Methods1484 patients underwent FFR_CT; 1910 vessels were stratified by stenosis severity (normal; <25%, 25–50%, 50–70%, and >70% stenosis). The rates of positive FFR_CT (≤0.8) were determined by measuring FFR_CT from the terminal vessel and from distal-to-the-lesion. Reclassification rates from positive to negative FFR_CT were calculated. Diagnostic performance of FFR_CT relative to FFR_INV was evaluated in 182 vessels using linear regression, Bland Altman analysis, and receiver operating characteristic (ROC) curves.ResultsPositive FFR_CT was identified in 24.9% of vessels using terminal vessel FFR_CT and 10.1% using FFR_CT distal-to-the-lesion (p ?< ?0.001). FFR_CT obtained distal-to-the-lesion resulted in reclassification of 59.6% of positive terminal FFR_CT to negative FFR_CT. Relative to FFR_INV, there were improvements in specificity (50% to 86%, p ?< ?0.001), diagnostic accuracy (65% to 88%, p ?< ?0.001), positive predictive value (50% to 78%, p ?< ?0.001), and area-under-the-curve (AUC, 0.83 to 0.91, p ?< ?0.001) when FFR_CT was measured distal-to-the-lesion.ConclusionFFR_CT values from the terminal vessel should not be used to assess lesion-specific ischemia due to high rates of false positive results. FFR_CT measured distal-to-the-lesion improves the diagnostic performance of FFR_CT relative to FFR_INV, ensures that FFR_CT values are due to lesion-specific ischemia, and could reduce the rate of unnecessary invasive procedures.     

Anomalous intracavitary right coronary artery shown by cardiac CT: A potential hazard to be aware of before various interventions

Intracavitary right coronary arteries (RCAs) are uncommon (incidence of 0.09%-0.1%), having previously been reported nearly exclusively in autopsy series. However, more recently this entity has been detected prospectively by noninvasive cardiac computed tomography. Because many interventional procedures, including pacemaker placement and atrial flutter ablation, may be influenced by the presence of an intracavitary RCA, this entity is important to recognize. We report two cases of intracavitary right coronary artery discovered prospectively by cardiac computed tomography. In one of these cases, interventional management was altered based on our findings.     

Non-invasive assessment of coronary artery geometry using coronary CTA

AimTo assess the association of coronary artery geometry with the severity of coronary artery disease (CAD).Methods73 asymptomatic individuals at increased risk of CAD due to peripheral vascular disease (18 women, mean age 63.5 ± 8.2 years) underwent coronary computed tomography angiography (coronary CTA) using first generation dual-source CT. Curvature and tortuosity of the coronary arteries were quantified using semi-automatically generated centerlines. Measurements were performed for individual segments and for the entire artery. Coronary segments were labeled according to the presence of significant stenosis, defined as >70% luminal narrowing, and the presence of plaque. Comparisons were made by segment and by artery, using linear mixed models.ResultsOverall, median curvature and tortuosity were, respectively, 0.094 [0.071; 0.120] and 1.080 [1.040; 1.120] on a per-segment level, and 0.096 [0.078; 0.118] and 1.175 [1.090; 1.420] on a per-artery level. Curvature was associated with significant stenosis at a per-segment (p < 0.001) and per-artery level (p = 0.002). Curvature was 16.7% higher for segments with stenosis, and 13.8% higher for arteries with stenosis. Tortuosity was associated with significant stenosis only at the per-segment level (p = 0.002). Curvature was related to the presence of plaque at the per-segment (p < 0.001) and per-artery level (p < 0.001), tortuosity was only related to plaque at the per-segment level (p < 0.001).ConclusionCoronary artery geometry as derived from coronary CTA is related to the presence of plaque and significant stenosis.     

The Journal of Cardiovascular Computed Tomography year in review - 2018

Since the introduction of ≥64 detector row coronary computed tomography angiography (CCTA) as a noninvasive imaging modality, various clinical trials have established its diagnostic performance and prognostic significance when compared to other anatomic and functional tests for coronary artery disease (CAD). CCTA has been increasingly utilized for a wide range of clinical scenarios, driven by both advances in technology as well as data showing improvement in outcomes. Accumulating evidence has continually refined and supported the central role of CCTA within clinical care, and this year has witnessed continued evolution of the application of CCTA within healthcare and translational research. The purpose of the present review is to summarize the year of the Journal of Cardiovascular Computed Tomography (JCCT), highlighting the evidence base supporting the appropriate application of cardiac computed tomography across numerous clinical domains.