Coronary CT angiography in patients with high calcium score: evaluation of plaque characteristics and diagnostic accuracy

Our aim was to evaluate the plaque characteristics of coronary arteries related to significant stenosis with coronary CT angiography (CCTA) and to discuss the diagnostic accuracy of CCTA in patients with high calcium scores. After institutional review board approval, 110 patients (63 men; mean age: 67.1 ± 7.9 years) with Agatston scores >400 were retrospectively reviewed. Patients underwent Agatston calcium scoring and 64-slice CCTA, in addition to invasive coronary angiography (CAG). The composition (calcified, mixed, and non-calcified) and configuration (concentric, eccentric) of coronary artery plaques were analyzed on a per-segment basis by CCTA. We analyzed the differences in plaque composition and configuration between significant (≥ 50%) and non-significant (<50%) stenosis. Additionally, the diagnostic accuracy of stenosis according to plaque composition was evaluated by CCTA, using CAG as a reference method. Significant differences in plaque composition and configurations were observed between the two groups. In cases of significant stenosis, the proportions of concentric, mixed, and non-calcified plaques were significantly higher than those of eccentric and calcified plaques (P < 0.001). The sensitivity and positive predictive value of mixed (97.4, 87.6%) and non-calcified plaques (97.8, 95.7%) were significantly higher than those of calcified plaques (87.6, 67.2%). Although CCTA has limited value due to low diagnostic accuracy of calcified plaques, knowledge about the high frequencies of mixed and non-calcified plaques in significant stenosis help to make an accurate assessment of CAD with CCTA in patients with high calcium scores.     

Assessment of coronary in-stent restenosis: value of subtraction coronary computed tomography angiography

In conventional coronary computed tomography angiography (CCTA), metal artifacts are frequently observed where stents are located, making it difficult to evaluate in-stent restenosis. This study was conducted to investigate whether subtraction CCTA can improve diagnostic accuracy in the evaluation of in-stent restenosis. Subtraction CCTA was performed using 320-row CT in 398 patients with previously placed stents who were able to hold their breath for 25 s and in whom mid-diastolic prospective one-beat scanning was possible. Among these patients, 126 patients (94 men and 32 women, age 74 ± 8 years) with 370 stents who also underwent invasive coronary angiography (ICA) were selected as the subjects of this study. With ICA findings considered the gold standard, conventional CCTA was compared against subtraction CCTA to determine whether subtraction can improve diagnostic accuracy in the evaluation of in-stent restenosis. When non-assessable stents were considered to be stenotic, the diagnostic accuracy in the evaluation of in-stent restenosis was 62.7 % for conventional CCTA and 89.5 % for subtraction CCTA. When the non-assessable stents were considered to be non-stenotic the diagnostic accuracy was 90.3 % for conventional CCTA and 94.31 % for subtraction CCTA. When subtraction CCTA was used to evaluate only the 138 stents that were judged to be non-assessable by conventional CCTA, 116 of these stents were judged to be assessable, and the findings for 109 of them agreed with those obtained by ICA. Even for stents with an internal diameter of 2.5–3 mm, the lumen can be evaluated in more than 80 % of patients. Subtraction CCTA provides significantly higher diagnostic accuracy than conventional CCTA in the evaluation of in-stent restenosis.     

The diagnostic accuracy of coronary computed tomography angiography in patients with and without previous coronary interventions

BackgroundInvasive coronary angiography (ICA) is the gold standard for imaging coronary arteries and the severity of coronary artery disease (CAD). Coronary computed tomography angiography (CCTA) has undergone remarkable progress in the diagnosis of CAD.ObjectivesTo evaluate the effect of prior vs no previous coronary interventions on the diagnostic accuracy of CCTA as an alternative to ICA to improve health outcomes for patients with suspected CAD.MethodsA prospective cohort study was carried out among patients suspected of CAD and for evaluation of grafts and stents to investigate recurrent ischemic symptoms. 120 patients imaged by CCTA were then referred to ICA, which is considered the gold standard. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CCTA were assessed relative to ICA.ResultsBased on a per-patient analysis, the comparison with ICA reveals variations in sensitivity, specificity, PPV, NPV and accuracy of CCTA. In patients without any previous coronary interventions, the sensitivity was 97.8%, and specificity was 95.6%. The PPV and NPV were 97.8% and 95.5%, respectively. Regarding patients with coronary artery bypass grafts (CABG), the sensitivity was 95% and specificity 100%. The PPV and NPV were 100% and 90.9%, respectively. Regarding patients with prior percutaneous coronary intervention (PCI), the results were a sensitivity of 84.6%, specificity of 77.8%, PPV of 84.6% and NPV of 77.8%.ConclusionCCTA is a powerful diagnostic tool, especially for the evaluation of the major coronary arteries and evaluation of patients with prior CABG. ICA is recommended for evaluation of patients with an intracoronary stent.     

斑块钙化负荷影响冠状动脉CT血管造影诊断管腔狭窄的准确性

  目的  探究斑块钙化负荷对冠状动脉CT血管造影（CCTA）诊断管腔狭窄准确性的影响。  方法  选取上海市嘉定区中心医院放射科于2019年2月~2022年1月收治的100例患者作为研究对象,所有患者均行冠状动脉造影与CCTA检查,钙化容积与钙化积分以血管段为单位进行记录,按照钙化容积与钙化积分不同将患者分为4组,分析各组血管管腔狭窄程度并探究CCTA判断斑块钙化不同容积与积分的管腔狭窄准确性。  结果  100例患者中入选的钙化冠状动脉段共396个,按照15段进行计算,以管腔狭窄≥50%为有意义狭窄,得到敏感度、特异性、准确率、阳性预测值与阴性预测值分别为99.03%（204/206）、83.16%（158/ 190）、91.41%（362/396）、86.44%（204/236）、98.75%（158/160）;当钙化容积≤25 mm2、钙化积分≤80分时,敏感度、特异性、准确率、阳性预测值、阴性预测值均为100%;当196 mm2<钙化容积≤1375 mm2时,敏感度、特异性、准确率、阳性预测值、阴性预测值分别为85.71%、36.36%、75.47%、83.72%、40.00%;当钙化积分>200分时,敏感度、特异性、准确率、阳性预测值、阴性预测值分别为92.86%、75.00%、87.50%、89.66%、91.82%;CCTA诊断不同钙化容积管腔狭窄程度与不同钙化积分管腔狭窄程度的敏感度、特异性、准确率、阳性预测值、阴性预测值具有统计学意义（P<0.05）,其中诊断0~25 mm2钙化容积管腔狭窄程度与0~80分钙化积分管腔狭窄程度的敏感度、特异性、准确率、阳性预测值、阴性预测值最高。  结论  不同斑块钙化负荷对CCTA诊断管腔狭窄程度准确性的影响存在差异,应引起临床重视。      

冠状动脉CT血管成像中人工智能诊断冠心病的准确性

目的 观察冠状动脉CT血管成像(CCTA)中人工智能(AI)诊断冠心病(CHD)的准确性.方法 回顾性分析105例临床拟诊CHD患者间隔2周内CCTA及有创冠状动脉造影(ICA)资料.以ICA结果为金标准,分别以患者、冠状动脉及其节段为单位,计算AI判断冠状动脉狭窄程度≥50％的敏感度、特异度、阳性预测值、阴性预测值和...     

Subtraction coronary CT angiography using second-generation 320-detector row CT

The purpose of this study was to explore the feasibility of subtraction coronary computed tomography angiography (CCTA) by second-generation 320-detector row CT in patients with severe coronary artery calcification using invasive coronary angiography (ICA) as the gold standard. This study was approved by the institutional board, and all subjects provided written consent. Twenty patients with calcium scores of >400 underwent conventional CCTA and subtraction CCTA followed by ICA. A total of 82 segments were evaluated for image quality using a 4-point scale and the presence of significant (>50 %) luminal stenosis by two independent readers. The average image quality was 2.3 ± 0.8 with conventional CCTA and 3.2 ± 0.6 with subtraction CCTA (P < 0.001). The percentage of segments with non-diagnostic image quality was 43.9 % on conventional CCTA versus 8.5 % on subtraction CCTA (P = 0.004). The segment-based diagnostic accuracy for detecting significant stenosis according to ICA revealed an area under the receiver operating characteristics curve of 0.824 (95 % confidence interval [CI], 0.750–0.899) for conventional CCTA and 0.936 (95 % CI 0.889–0.936) for subtraction CCTA (P = 0.001). The sensitivity, specificity, positive predictive value, and negative predictive value for conventional CCTA were 88.2, 62.5, 62.5, and 88.2 %, respectively, and for subtraction CCTA they were 94.1, 85.4, 82.1, and 95.3 %, respectively. As compared to conventional, subtraction CCTA using a second-generation 320-detector row CT showed improvement in diagnostic accuracy at segment base analysis in patients with severe calcifications.     

Patterns of coronary arterial lesion calcification by a novel, cross-sectional CT angiographic assessment

To investigate the patterns and diagnostic implications of coronary arterial lesion calcification by CT angiography (CTA) using a novel, cross-sectional grading method, we studied 371 patients enrolled in the CorE-64 study who underwent CTA and invasive angiography for detecting coronary artery stenoses by quantitative coronary angiography (QCA). The number of quadrants involving calcium on a cross-sectional view for ≥30 and ≥50 % lesions in 4,511 arterial segments was assessed by CTA according to: noncalcified, mild (one-quadrant), moderate (two-quadrant), severe (three-quadrant) and very severe (four-quadrant calcium). Area under the receiver operating characteristic curve (AUC) were used to evaluate CTA diagnostic accuracy and agreement versus. QCA for plaque types. Only 4 % of ≥50 % stenoses by QCA were very severely calcified while 43 % were noncalcified. AUC for CTA to detect ≥50 % stenoses by QCA for non-calcified, mildly, moderately, severely, and very severely calcified plaques were 0.90, 0.88, 0.83, 0.76 and 0.89, respectively (P < 0.05). In 198 lesions with severe calcification, the presence or absence of a visible residual lumen by CTA was associated with ≥50 % stenosis by QCA in 20.3 and 76.9 %, respectively. Kappa was 0.93 for interobserver variability in evaluating plaque calcification. We conclude that calcification of individual coronary artery lesions can be reliably graded using CTA. Most ≥50 % coronary artery stenoses are not or only mildly calcified. If no residual lumen is seen on CTA, calcified lesions are predictive of ≥50 % stenoses and vice versa. CTA diagnostic accuracy for detecting ≥50 % stenoses is reduced in lesions with more than mild calcification due to lower specificity.     

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.     

320排动态容积CT冠状动脉成像诊断冠心病:ROC曲线分析

目的应用ROC曲线分析方法评价320排动态容积CT冠状动脉成像(CCTA)诊断冠心病(CHD)的价值。方法回顾性分析临床疑似冠心病的37例患者的CCTA和冠状动脉造影(CAG)资料,以冠状动脉狭窄≥50%作为冠心病诊断标准,对结果采用配对t检验及ROC曲线分析。结果 CCTA诊断冠心病的敏感度为78.57%(55/70),特异度为95.13%(391/411),阳性预测值为73.33%(55/75),阴性预测值为96.31%(391/406),准确率为92.72%(446/481);CCTA和CAG结果呈高度相关性;CCTA的ROC曲线下面积为0.962。CCTA诊断的斑块数量较CAG多(68vs 45)。结论 320排动态容积CCTA诊断冠状动脉狭窄具有较高的准确性,能有效识别斑块及其危险程度。     

冠状动脉CT血管造影对先天性右冠状动脉缺如的评价价值

目的总结先天性右冠状动脉缺如患者的临床和冠状动脉CT血管造影（CCTA）影像表现。方法回顾性分析2014年1月~2019年6月于本院行CCTA检查并经选择性冠状动脉造影（SCA）确诊的13例先天性右冠状动脉缺如患者的临床资料和CCTA影像表现。结果13例先天性右冠状动脉缺如患者的临床表现缺乏特异性,大多表现为心血管疾病的临床症状。CCTA平扫显示左主干、左前降支和（或）左回旋支走行区内数量不等、形态各异的高密度钙化斑块形成;增强扫描显示左主干、左前降支和（或）左回旋支不同程度变窄,升主动脉和右冠状窦区均未见右冠状动脉发出,左主干、左前降支和左回旋支均不同程度增粗,并左回旋支延伸至右心室背面,进而发出分支供应右心房和右心室。CCTA与SCA表现基本一致。结论先天性右冠状动脉缺如罕见,其临床表现缺乏特异性,仅凭临床表现往往难以诊断,CCTA联合SCA检查常可用于确诊。      

Feasibility and diagnostic performance of fractional flow reserve measurement derived from coronary computed tomography angiography in real clinical practice

Non-invasive fractional flow reserve measured by coronary computed tomography angiography (FFR_CT) has demonstrated a high diagnostic accuracy for detecting coronary artery disease (CAD) in selected patients in prior clinical trials. However, feasibility of FFR_CT in unselected population have not been fully evaluated. Among 60 consecutive patients who had suspected significant CAD by coronary computed tomography angiography (CCTA) and were planned to undergo invasive coronary angiography, 48 patients were enrolled in this study comparing FFR_CT with invasive fractional flow reserve (FFR) without any exclusion criteria for the quality of CCTA image. FFR_CT was measured in a blinded fashion by an independent core laboratory. FFR_CT value was evaluable in 43 out of 48 (89.6?%) patients with high prevalence of severe calcification in CCTA images [calcium score (CS) >400: 40?%, and CS?>?1000: 19?%). Per-vessel FFR_CT value showed good correlation with invasive FFR value (Spearman’s rank correlation?=?0.69, P?<?0.001). The area under the receiver operator characteristics curve (AUC) of FFR_CT was 0.87. Per-vessel accuracy, sensitivity, specificity, positive predictive value, and negative predictive value were 68.6, 92.9, 52.4, 56.5, and 91.7?%, respectively. Even in eight patients (13 vessels) with extremely severely calcified lesions (CS?>?1000), per-vessel FFR_CT value showed a diagnostic performance similar to that in patients with CS?≤?1000 (Spearman’s rank correlation?=?0.81, P?<?0.001). FFR_CT could be measured in the majority of consecutive patients who had suspected significant CAD by CCTA in real clinical practice and demonstrated good diagnostic performance for detecting hemodynamically significant CAD even in patients with extremely severe calcified vessels.     

64层螺旋CT冠状动脉成像在冠心病诊断中的初步应用

目的 评价64层螺旋CT冠状动脉成像（coronary 64-slice computed tomographic angiography,64S-CCTA）在诊断冠状动脉疾病（CAD）中的临床应用价值.方法 回顾性分析92例行64S-CCTA患者完整资料,并以近期（2周之内）实施的X线冠状动脉造影检查（coronary artery disease,CAG）结果为金标准进行对比.结果 所有可用于评估1,129段冠脉中,64S-CCTA显示轻度和明显狭窄病变各为122、231段,其中各有61、198段得到CAG证实;64S-CCTA判断冠状动脉明显狭窄的灵敏度、特异度、阳性预测值、阴性预测值、阳性似然比、阴性似然比分别为88.39%、96.35%、85.71%、97.10%及24.22、0.12;在CAG确诊狭窄节段中,64S-CCTA在轻度狭窄和明显狭窄中分别检测出非钙化性斑块、钙化斑块各为32、65 和154、53个.结论 64S-CCTA是一种简便、可靠的无创性检查方法,对病变血管管腔狭窄及不同性质粥样硬化斑块与狭窄关系的评价有一定价值,可作为临床拟诊冠心病患者筛查的有效手段.     

Improved evaluation of calcified segments on coronary CT angiography: a feasibility study of coronary calcium subtraction

We explore the feasibility of coronary calcium subtraction computed tomography angiography (CCTA) in patients with high calcium scores using invasive coronary angiography as the gold standard. Eleven patients with calcium scores of >400 underwent CCTA using a subtraction protocol followed by invasive coronary angiography. In addition to standard reconstructions, subtracted images were obtained using a dedicated subtraction algorithm. A total of 55 calcified segments were evaluated for image quality [using a 4-point scale ranging from 1 (uninterpretable) to 4 (good)] and the presence of significant (≥50 %) luminal stenosis. Conventional and subtracted CCTA were compared using quantitative coronary angiography (QCA) as the gold standard. The average image quality of conventional CCTA was 2.5 ± 0.6 versus 3.1 ± 0.6 on subtraction CCTA (P < 0.001). The percentage of segments with a score 1 or 2 was reduced from 41.8 to 12.7 % after coronary calcium subtraction (P = 0.002). On QCA, significant stenosis was observed in 16 segments. The area under the receiver operating characteristics curve to detect ≥50 % stenosis on QCA increased from 0.741 [95 % confidence interval (CI) 0.598–0.885] for conventional CCTA to 0.905 (95 % CI 0.791–1.000) for subtraction CCTA (P = 0.003). In patients with extensive calcifications undergoing CCTA, coronary calcium subtraction may improve the evaluation of calcified segments.     

64排螺旋CT对伴有钙化的冠状动脉狭窄诊断准确性的多中心研究

评价64排螺旋CT在不同情况下对冠状动脉钙化病变所致狭窄的诊断准确性. 方法 收集165例经CT冠状动脉成像(CTCA)检查发现冠状动脉钙化并至少1个主要分支狭窄＞50%的患者,分别以个体、冠状动脉主支、节段、病变狭窄程度及钙化斑块形态为分析对象,测量Agatston积分(ACS)和狭窄率.以冠状动脉造影(CAG)作为标准,通过绘制ROC曲线来判定不同情况下CTCA的诊断价值并确定最佳的诊断切点. 结果 以个体为分析对象,ROC曲线下面积为0.791,以ACS值113.5为切点时诊断准确性最高.以冠状动脉主支为分析对象,对右冠状动脉及其属支狭窄的诊断效果最佳,ROC曲线下面积为0.897.以冠状动脉节段为分析对象,对RCA1段狭窄诊断准确性最高,ROC曲线下面积为0.894.以钙化斑块形态为研究对象,ROC曲线下面积仅在0.601～0.667之间,诊断价值较低.CTCA对狭窄程度＜50%的狭窄诊断价值较大,曲线下面积为0.856. 结论 CTCA中,钙化对不同主支、不同节段及不同狭窄程度冠状动脉狭窄的诊断准确性影响不同;钙化斑块的形态不是影响诊断准确性的主要因素.     

Variation in atherosclerotic plaque composition according to increasing coronary artery calcium scores on computed tomography angiography

Increasing coronary artery calcium scores (CACS) are independently associated with cardiac events. Recent advents in coronary computed tomography angiography (CCTA) have allowed us to better characterize individual plaque. Currently, it is unknown if higher CACS are likely to be associated with more calcified or mixed and heterogeneous plaque burden on CCTA. The study population consisted of 1,043 South Korean asymptomatic subjects (49 ± 10 years, 62% men) who underwent CCTA (64-slice MDCT). Plaques were classified on contrast-enhanced CCTA as non-calcified, mixed, and calcified on a per-segment basis according to the modified American Heart Association classification. The majority of the study participants had no coronary calcification (n = 866, 83%), whereas CACS> 0 was observed in 177 participants (17%). Only 40 (5%) participants in absence of CACS had exclusively non-calcified plaque, whereas 10 (1.2%) had significant coronary artery disease. With increasing CACS, study participants were more likely to have exclusively mixed or combination atherosclerotic plaques (P = 0.001). Among individuals with CACS 1–10, the prevalence of at least two coronary segments with mixed plaques was 4%, increasing up to 18 and 41% with CACS of 11–100 and >100. The respective prevalence of ≥2 coronary segments (calcified plaques) with increasing CACS were 6%, 16 and 26% (P = 0.01) and of non-calcified plaques were 6%, 6 and 11% (P = 0.71). In multivariable adjusted analyses, those with CACS >100 were 7.17 times (95% CI: 1.36–37.68) more likely to have ≥2 coronary segments with calcified plaque comparing with CACS 1–10. On the other hand the respective risk was higher for presence of ≥2 segments with mixed plaques (odds ratio: 15.81, 95% CI: 3.14–79.58). Absence of CAC is associated with a negligible presence of any atherosclerotic disease as detected by CCTA in asymptomatic population. A higher CACS is more likely to be associated with heterogeneous coronary plaque (combination of calcified, non-calcified, and mixed plaques), and appears to be more strongly associated with a higher burden of mixed plaque.     

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.     

CT coronary angiography: impact of adapted statistical iterative reconstruction (ASIR) on coronary stenosis and plaque composition analysis

To assess the impact of adaptive statistical iterative reconstruction (ASIR) on coronary plaque volume and composition analysis as well as on stenosis quantification in high definition coronary computed tomography angiography (CCTA). We included 50 plaques in 29 consecutive patients who were referred for the assessment of known or suspected coronary artery disease (CAD) with contrast-enhanced CCTA on a 64-slice high definition CT scanner (Discovery HD 750, GE Healthcare). CCTA scans were reconstructed with standard filtered back projection (FBP) with no ASIR (0 %) or with increasing contributions of ASIR, i.e. 20, 40, 60, 80 and 100 % (no FBP). Plaque analysis (volume, components and stenosis degree) was performed using a previously validated automated software. Mean values for minimal diameter and minimal area as well as degree of stenosis did not change significantly using different ASIR reconstructions. There was virtually no impact of reconstruction algorithms on mean plaque volume or plaque composition (e.g. soft, intermediate and calcified component). However, with increasing ASIR contribution, the percentage of plaque volume component between 401 and 500 HU decreased significantly (p < 0.05). Modern image reconstruction algorithms such as ASIR, which has been developed for noise reduction in latest high resolution CCTA scans, can be used reliably without interfering with the plaque analysis and stenosis severity assessment.     

冠状动脉钙化对320排容积CT冠状动脉血管成像的影响

目的 探讨320排容积CT（DVCT）冠状动脉钙化（CAC）对冠状动脉图像质量及诊断准确性的影响.方法 回顾性分析济南军区总医院2011年12月至2012年3月行DVCT扫描及常规冠状动脉造影检查（ICA）的患者60例,计算每例患者总的钙化积分（CS）及四大分支的CS,以图像质量4级（优）至1级（差）对每支血管图像质量进行评价,分析患者每支血管的CS与图像质量的相关性.对患者及每支冠状动脉血管的明显狭窄（狭窄≥50%）进行判断,以ICA为金标准,作出该60例患者冠状动脉狭窄≥50%的ROC曲线,获得患者总CS的最佳截断点.以最佳截断点为界,将60例患者分为高CS组和低CS组,以每支冠状动脉为研究对象,不可评价的血管作为假阳性处理,对高、低CS组的诊断准确性进行比较,同时比较两组DVCT冠状动脉成像结果 与ICA结果 的差异性,分析CS对冠心病诊断准确性的影响.结果 冠状动脉钙化积分（CACS）与图像质量呈负相关,CS越高,图像质量越差.该60例患者的冠状动脉狭窄≥50%的ROC曲线的CS最佳截断点为381.5分（灵敏度为81.5%,特异度为78.8%）.高CS组的诊断准确性低于低CS组（P=0.009）,而两组DVCT结果 与ICA结果 的差异均无统计学意义（P=0.134,0.607）.结论 CAC仍是320排容积CT图像质量及诊断准确性下降的重要原因.     

Impact of luminal density on plaque classification by CT coronary angiography

Non-invasive coronary CT angiography (CCTA) has the potential to characterize the composition of non-calcified coronary plaques. CT-density values characterized by Hounsfield Units (HU) may classify non-calcified plaques as fibrous or lipid-rich, but the luminal density caused by the applied contrast material influences HU in the plaques in vitro. The influence of luminal density on HU in non-calcified plaques in vivo is unknown. Hence the purpose of this study was to test whether plaque characterization by CCTA in vivo depends on luminal density. Two CCTA-scans using two different contrast protocols were obtained from 14 male patients with coronary artery disease. The two contrast protocols applied resulted in high and low luminal density. Eleven non- calcified and 13 calcified plaques were identified and confirmed by intravascular ultrasound. Luminal attenuation differed with the two contrast protocols; 326[284;367] vs. 118[103;134] HU (P < 0.00001). In non-calcified plaques mean HU-values was lower 48[28;69] vs. 11[−4;25] HU (P = 0.004) with the low density protocol. As a consequence three out of eleven non-calcified plaques (27%) were reclassified from fibrous (high) to lipid rich (low). For calcified plaques a less pronounced but still significant difference in HU-values was found with the low luminal density. 770[622;919] vs. 675[496;855] HU (P = 0.02). Conclusion: Non-calcified plaques can be identified and classified by CCTA. However, the luminal density affects the absolute HU of both non-calcified and calcified plaques. Characterization and classification of non-calcified plaques by absolute CT values therefore requires standardization of contrast protocols.     

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0.0869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,以之作为评价指标,可明显提高评估冠状动脉钙化及狭窄程度的准确性。