Characterization of coronary atherosclerotic plaques by multidetector computed tomography

Multidetector computed tomography (MDCT) provides 3-dimensional noninvasive visualization of the coronary arterial tree. We compared MDCT with intravascular ultrasound (IVUS) for assessment of severity of coronary artery stenosis and composition of atherosclerotic plaques in 40 patients (32 men; mean age 52 years, range 33 to 86) with documented coronary artery disease. Cross-sectional images obtained at 10-mm increments were assessed for percent decrease in luminal area. Atherosclerotic plaques were classified by IVUS as soft, fibrous, or calcified. On the matched multidetector computed tomograms, regions of interest of 1 to 3 mm in diameter were placed inside each plaque, and tissue contrast was measured in Hounsfield units. Obstructive coronary artery disease was found in 50 segments by IVUS and 57 segments by MDCT. Sensitivity for detecting obstruction >50% was 86.0% (95% confidence interval 72.6 to 93.7) and specificity was 90.2% (95% confidence interval 83.9 to 94.4). In total, 276 plaques were examined by IVUS and MDCT. There were 188 soft plaques (68.2%), 45 fibrous plaques (16.2%), and 43 calcified plaques (15.5%). Multidetector computed tomographic tissue contrast of soft, fibrous, and calcified plaques were 71.5 +/- 32.1, 116.3 +/- 35.7, and 383.3 +/- 186.1, respectively (p <0.001). Using a cut-off value of 185 HU, 273 of 276 plaques (99%) were correctly classified as calcified or noncalcified plaques. Using a cut-off value of 88 HU, 192 of 233 noncalcified plaques (82%) were correctly classified as fibrous or soft plaques. In conclusion, our data indicate that MDCT can provide important information concerning the composition of atherosclerotic plaques in addition to detecting luminal obstruction.     

Diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of atherosclerotic plaque composition in ex-vivo coronary specimens: a comparison with histology

BACKGROUND: Both intravascular ultrasound and optical coherence tomography have been purported to accurately detect and characterize coronary atherosclerotic plaque composition. The aim of our study was to directly compare the reproducibility and diagnostic accuracy of optical coherence tomography and intravascular ultrasound for the detection and characterization of coronary plaque composition ex vivo as compared with histology. METHODS AND RESULTS: Intravascular ultrasound (20 MHz) and optical coherence tomography imaging was performed in eight heart specimens using motorized pullback. Standard histology using hematoxylin-eosin and van Gieson staining was performed on 4 mum thick slices. Each slice was divided into quadrants and accurately matched cross-sections were analyzed for the presence of fibrous, lipid-rich, and calcified coronary plaque using standard definitions for both intravascular ultrasound and optical coherence tomography and correlated with histology. After exclusion of 145/468 quadrants, we analyzed the remaining 323 quadrants with excellent image quality in each procedure. Optical coherence tomography demonstrated a sensitivity and specificity of 91/88% for normal wall, 64/88% for fibrous plaque, 77/94% for lipid-rich plaque, and 67/97% for calcified plaque as compared with histology. Intravascular ultrasound demonstrated a sensitivity and specificity of 55/79% for normal wall, 63/59% for fibrous plaque, 10/96% for lipid-rich plaque, and 76/98% for calcified plaque. Both intravascular ultrasound and optical coherence tomography demonstrated excellent intraobserver and interobserver agreement (optical coherence tomography: kappa=0.90, kappa=0.82; intravascular ultrasound: kappa=0.87, kappa=0.86). CONCLUSION: Optical coherence tomography is superior to intravascular ultrasound for the detection and characterization of coronary atherosclerotic plaque composition, specifically for the differentiation of noncalcified, lipid-rich, or fibrous plaque.     

Comparison of 64-slice multidetector computed tomography with spectral analysis of intravascular ultrasound backscatter signals for characterizations of noncalcified coronary arterial plaques

In vivo identification of plaque composition may allow the detection of vulnerable plaques before rupture. However, the clinical relevance of multidetector computed tomography (MDCT) in characterizing coronary plaques is currently a subject of debate. We compared 64-slice MDCT with virtual histology to investigate the potential role of 64-slice MDCT in the differentiation of composition of noncalcified coronary plaques. Fifty-nine consecutive patients (stable/unstable angina 34/21) were enrolled. Mean computed tomographic (CT) density (Hounsfield units) of noncalcified coronary plaques (n = 80) was compared with a relative volume of each plaque component (fibrous, fibrofatty, calcium, and necrotic core) analyzed by virtual histology. Mean heart rate during MDCT was 58 +/- 9 beats/min. There was a negative correlation between mean CT density and the necrotic core (r = -0.539, p <0.001) and a positive correlation between mean CT density and the fibrotic tissue component (r = 0.571, p <0.001). Mean CT density of the plaques with a <10% necrotic core was significantly higher than that of a >or=10% necrotic core (93.1 +/- 37.5 vs 41.3 +/- 26.4 HU, p <0.001). However, overlapping of mean CT densities between plaques with a <10% necrotic core and those with a >or=10% necrotic core was found. In conclusion, mean CT density of noncalcified coronary plaques measured by 64-slice MDCT may depend on the relative volumes of the necrotic core and fibrotic component. Sixty-four-slice MDCT may have the potential for determining composition of noncalcified coronary plaques, which needs further studies for clinical application.     

64层CTA结合血清MMP-9、sCD40L评价冠脉临界病变斑块成分及稳定性

目的:通过64层计算机体层摄影冠状动脉血管造影识别冠状动脉临界病变患者的冠脉斑块成分,并检测血清基质金属蛋白酶-9（MMP-9）、可溶性CD40配体（sCD40L）水平,探讨其斑块稳定性及临床意义。方法: 选择经64层计算机体层摄影冠状动脉血管造影证实至少有1支冠脉某一阶段狭窄30%～70%的患者65例,其中稳定型心绞痛36例,不稳定型心绞痛29例,通过斑块CT值及冠脉管腔碘造影剂CT值确定其斑块类型:非钙化斑块,钙化斑块和混合斑块;并用ELISA方法测定患者及37例无心血管疾病对照组血清MMP-9、sCD40L水平,比较其差异性并探讨其相互关系。结果: 冠脉临界病变患者混合斑块最多,其次为非钙化斑块,钙化斑块最少,“混合斑块+非钙化斑块”显著多于钙化斑块数目;患者血清MMP-9、sCD40L水平显著高于无心血管疾病对照组。结论: 冠心病冠脉临界病变斑块多为易损斑块。     

64层双源螺旋CT与血管内超声对冠状动脉粥样硬化斑块性质的对比研究

目的对比冠状动脉血管内超声(IVUS)与64层双源螺旋CT(64-sCT)检查对冠状动脉粥样硬化斑块特征判定的准确性。方法选择35例不稳定性心绞痛患者行64-sCT与IVUS检查,分别测定同一病变同一位置的血管横截面积、管腔横截面积、斑块负荷;采用IVUS判定斑块性质,64-sCT测定其CT值。结果 45支血管(左前降支23支;左回旋支15支;右冠状动脉7支)的72个不同截面行IVUS与64-sCT检查,在可用于评估的68个截面中,64-sCT对51个存在斑块的截面,正确显示49个存在斑块(敏感性96%),对提示17个无斑块的截面,正确显示16个无斑块存在(特异性94%)。脂质斑块(25±14)HU、纤维斑块(90±20)HU、钙化斑块(530±185)HU;混合斑块中,钙化-脂质斑块(540±175)HU、钙化-纤维斑块(540±195)HU、纤维-脂质斑块(91±22)HU。纤维-脂质斑块与纤维斑块差异无统计学意义;钙化-脂质斑块、钙化-纤维斑块与钙化斑块差异无统计学意义。靶血管外弹力膜截面积、管腔截面积、斑块负荷、狭窄程度之间差异无统计学意义。结论对比IVUS与64-sCT检查能够定性及定量分析冠状动脉粥样硬化斑块,但其精确度仍有一定的限制。     

Atherosclerotic plaque characterization by 0.5-mm-slice multislice computed tomographic imaging.

BACKGROUND: It has been proposed that 0.5-mm-slice multislice computed tomography (MSCT) is a noninvasive tool for the detection of atherosclerotic plaque, but the validity of such an assessment has not been demonstrated by an invasive investigation. The present study was performed to compare the 0.5-mm-slice MSCT density of plaques with intravascular ultrasound (IVUS) findings. METHODS AND RESULTS: Atherosclerotic plaques were characterized in 37 consecutive patients undergoing percutaneous interventions. Based on the IVUS echogenecity, the plaques were classified as soft (n=18), fibrous (n=40) or calcified (n=40). In these 98 plaques, 0.5-mm-slice MSCT plaque density was calculated in 443 regions-of-interest, including 331 lesional foci and 112 luminal cross-sections, and represented as Hounsfield units (HU). MSCT density of the 3 types of plaque was 11+/-12 HU, 78+/-21 HU, and 516 +/-198 HU respectively. Computed tomography density of the (contrast-filled) lumen was 258+/-43 HU. There were statistically highly significant differences in the densitometric characteristics among the 4 groups (soft, fibrous, calcified plaque and lumen) by nonparametric Kruskal-Wallis test (p<0.0001). CONCLUSIONS: The IVUS-based coronary plaque configuration can be accurately identified by 0.5-mm slice MSCT. Noninvasive assessment of plaque characterization will ensure emphasis on the vessel wall beyond the vascular lumen.     

Magnetic resonance imaging and computed tomography in assessment of atherosclerotic plaque

The two most promising noninvasive imaging modalities for the study of atherosclerosis are magnetic resonance imaging (MRI) and computed tomography (CT). Both have been shown to be capable of imaging vessel wall structures and differentiating various stages of atherosclerotic wall changes. MRI has been applied in various in vivo human studies to image atherosclerotic plaques in coronary arteries, carotid arteries, and aorta. The latest generation of multidetector row computed tomography (MDCT) systems allows for the noninvasive characterization of different plaque components in various vascular structures. MDCT allows evaluation of the whole arterial vasculature. In addition, MDCT has the ability to visualize the vessel wall and to give a quantitative measurement of calcified and noncalcified plaque. Using either technique, the repeatable, noninvasive study of atherosclerotic disease during its natural history and after therapeutic intervention will enhance our understanding of disease progression and regression. MDCT and MRI, therefore, may help in selecting appropriate treatments.     

不同类型冠状动脉斑块支架植入术的比较

目的 回顾性分析冠状动脉支架术前已行64层螺旋CT冠状动脉成像的病例,比较不同类型冠状动脉斑块支架术的差异.方法 选择2007年至2009年支架术前已行64层螺旋CT检查的患者86例,共植入支架137处.依据冠状动脉斑块平均CT值将冠状动脉斑块分为非钙化斑块组和钙化斑块组.比较两组的临床特征、预扩张球囊规格、预扩张球囊充盈压力、支架规格和支架释放压力.结果 与非钙化斑块组相比,钙化斑块组年龄相对较高,低密度脂蛋白更低,单支病变较少.两组的预扩张球囊和支架规格无明显差异.钙化斑块组预扩张球囊充盈压力(898.93±159.67 kPa)明显高于非钙化斑块组(810.22±112.61 kPa,P<0.01).钙化斑块组支架释放压力(1 403.90±273.12 kPa)明显高于非钙化斑块组(1 243.79±254.12 kPa,P<0.01).结论 与非钙化斑块相比,钙化斑块对预扩张和支架成形有较大阻力,硬度较高,术前识别斑块类型对支架术有一定意义.     

Selective coronary artery plaque visualization and differentiation by contrast-enhanced inversion prepared MRI.

AIMS: We sought to evaluate the utility of contrast-enhanced coronary magnetic resonance imaging (CE-MRI) for selective visualization and non-invasive differentiation of atherosclerotic coronary plaque in humans. METHODS AND RESULTS: Nine patients with coronary artery disease (CAD) as confirmed by X-ray angiography and multidetector computed tomography (MDCT) were studied by T1-weighted black blood inversion recovery coronary MRI before (N-IR) and after administration of Gd-DTPA (CE-IR). Plaques were categorized as calcified, non-calcified, and mixed based on their Hounsfield number derived from MDCT. With MDCT, a total of 29 plaques were identified, including calcified (n=6), non-calcified (n=6), and mixed calcified/non-calcified (n=17). On N-IR MRI, 26 plaques (90%) were dark, whereas three plaques (two non-calcified and one mixed) appeared bright. On CE-MRI, 13/29 (45%) plaques, 11 of which were mixed, one non-calcified, and one calcified showed contrast uptake. All others remained dark. CONCLUSION: In this preliminary study, we demonstrate the potential utility of CE-IR MRI for selective plaque visualization and differentiation of plaque types. The observed contrast uptake may be associated with endothelial dysfunction, neovascularization, inflammation, and/or fibrosis.     

Accuracy of 64-slice computed tomography to classify and quantify plaque volumes in the proximal coronary system: a comparative study using intravascular ultrasound.

OBJECTIVES: We evaluated the accuracy of a new 64-slice computed tomography (CT) scanner, compared with intravascular ultrasound, to visualize atherosclerosis in the proximal coronary system. BACKGROUND: Noninvasive determination of plaque composition and plaque burden may be important to improve risk stratification. METHODS: In 20 patients, a 64-slice CT scan (Sensation 64, Siemens Medical Solutions, Forchheim, Germany) and an intravascular ultrasound investigation of vessels without stenosis >50% was performed. Diagnostic image quality with 64-slice CT was obtained in 36 vessels in 19 patients. RESULTS: In these vessels, which were divided in 3-mm sections, 64-slice CT enabled a correct detection of plaque in 54 of 65 (83%) sections containing noncalcified plaques, 50 of 53 (94%) sections containing mixed plaques, and 41 of 43 (95%) sections containing calcified plaques. In 192 of 204 (94%) sections, atherosclerotic lesions were excluded correctly. In addition, 64-slice CT enabled the visualization of 7 of 10 (70%) sections revealing a lipid pool and could identify a spotty calcification pattern in 27 of 30 (90%) sections. The correlation coefficient to determine plaque volumes per vessel was r2 = 0.69 (p < 0.001) with an underestimation of mixed and noncalcified plaque volumes (p < 0.03) and a trend to overestimate calcified plaque volumes by 64-slice CT. The interobserver variability to determine plaque volumes was 37%. Interobserver agreement to identify atherosclerotic sections was good (Cohen's kappa coefficient = 0.75). CONCLUSIONS: We conclude that 64-slice CT reveals encouraging results to noninvasively detect different types of coronary plaques located in the proximal coronary system. The ability to determine plaque burden currently is hampered by mainly an insufficient reproducibility.     

16排螺旋CT对冠状动脉斑块的诊断价值

目的探讨16排螺旋CT（16-mulddetector spiral computed tomography,16-MDCT）检测和区分冠状动脉斑块的准确性。方法对2005年8月至2006年3月68例拟诊为冠心病的患者先行16-MDCT检查,4天内再行定量冠状动脉造影（QCA）和血管内超声（IVUS）检查,冠状动脉血管腔直径狭窄（DS）≥50％定义为有意义的狭窄,分别测量斑块的CT密度,单位为CT值（Hounsfield units,HU）,根据冠状动脉斑块的CT值区分斑块性质并作出分类：（1）软斑块：CT值为≤50HU;（2）纤维斑块（中等斑块）：CT值为50—119HU;（3）钙化斑块≥120HU。结果在112段16-MDCT和QCA均诊断为冠状动脉狭窄≥50％的病变中,其敏感性为91．8％（112／122）,特异性为97．8％（556／568）,共96段有意义的狭窄病变纳入研究,分别位于左前降支57段,左回旋支17段,右冠状动脉14段,左主干8段。IVUS发现软斑块21个（21．9％）、纤维斑块36个（37．5％）、钙化斑块38个（39．5％）,混合性斑块（纤维钙化斑块）1个（1．1％）,16-MDCT发现软斑块20个,平均CT值（11±36）HU（-27～42HU）、纤维斑块37个,平均CT值（83±20）Hu（58—105HU）、钙化斑块39个,平均CT值（292±80）HU（167—530HU）,差异有统计学意义（P〈0．05）。结论无创性16排螺旋CT冠状动脉成像技术不仅可诊断冠状动脉狭窄病变,同时对区分钙化斑块及非钙化斑块有较高的诊断价值。     

Comparison of the relation between the calcium score and plaque characteristics in patients with acute coronary syndrome versus patients with stable coronary artery disease, assessed by computed tomography angiography and virtual histology intravascular ultrasound

A considerable number of patients with an acute coronary syndrome (ACS) who present with a 0 or low calcium score (CS) still demonstrate coronary artery disease (CAD) and significant stenosis. The aim of the present study was to evaluate the relation between the CS and the degree and character of atherosclerosis in patients with suspected ACS versus patients with stable CAD obtained by computed tomography angiography and virtual histology intravascular ultrasound (VH IVUS). Overall 112 patients were studied, 53 with ACS and 59 with stable CAD. Calcium scoring and computed tomography angiography were performed and followed by VH IVUS. On computed tomography angiography each segment was evaluated for plaque and classified as noncalcified, mixed, or calcified. Vulnerable plaque characteristics on VH IVUS were defined by percent necrotic core and presence of thin-cap fibroatheroma. If the CS was 0, patients with ACS had a higher mean number of plaques (5.0 ± 2.0 vs 2.0 ± 1.9, p <0.05) and noncalcified plaques (4.6 ± 3.5 vs 1.3 ± 1.9, p <0.05) on computed tomography angiography than those with stable CAD. If the CS was 0, VH IVUS demonstrated that patients with ACS had a larger amount of necrotic core area (0.58 ± 0.73 vs 0.22 ± 0.43 mm(2), p <0.05) and a higher mean number of thin-cap fibroatheromas (0.6 ± 0.7 vs 0.1 ± 0.3, p <0.05) than patients with stable CAD. In conclusion, even in the presence of a 0 CS, patients with ACS have increased plaque burden and increased vulnerability compared to patients with stable CAD. Therefore, absence of coronary calcification does not exclude the presence of clinically relevant and potentially vulnerable atherosclerotic plaque burden in patients with ACS.     

Intracoronary imaging using attenuation-compensated optical coherence tomography allows better visualisation of coronary artery diseases

PurposeTo allow an accurate diagnosis of coronary artery diseases by enhancing optical coherence tomography (OCT) images of atheromatous plaques using a novel automated attenuation compensation technique.BackgroundOne of the major drawbacks of coronary OCT imaging is the rapid attenuation of the OCT signal, limiting penetration in tissue to only few millimetres. Visualisation of deeper anatomy is however critical for accurate assessment of plaque burden in-vivo.MethodsA compensation algorithm, previously developed to correct for light attenuation in soft tissues and to enhance contrast in ophthalmic OCT images, was applied to intracoronary plaque imaging using spectral-domain OCT.ResultsApplication of the compensation algorithm significantly increased tissue contrast in the vessel wall and atherosclerotic plaque boundaries. Contrast enhancement allows a better differentiation of plaque morphology, which is particularly important for the identification of lipid rich fibro atheromatous plaques and to guide decision on treatment strategy.ConclusionThe analysis of arterial vessel structure clinically captured with OCT is improved when used in conjunction with automated attenuation compensation. This approach may improve the OCT-based interpretation of coronary plaque morphology in clinical practice.     

Relation of the metabolic syndrome to quantity of coronary atherosclerotic plaque

Although metabolic syndrome (MS) is associated with adverse cardiovascular outcomes, its association with the presence and extent of coronary atherosclerotic plaques is not well described. To assess this relation, multidetector computed tomography-based patterns of coronary plaque were assessed in 77 patients enrolled in the ROMICAT study (age 54 +/- 12 years; 79% Caucasians, and 36% women) and compared between those who did (n = 35; 45%) and did not (n = 42; 55%) have MS. The presence of any, calcified, and noncalcified plaque was significantly higher in patients with than without MS (91%, 74%, and 77% vs 46%, 45%, and 40% segments with plaque, respectively; all p <0.01). The overall number of segments with plaques was also higher in patients with MS (5.8 +/- 3.7 vs 2.1 +/- 3.3; p <0.001). MS was independently associated with both the presence and extent of overall plaques after adjusting for the Framingham risk score (odds ratio 6.7, 95% confidence interval 1.6 to 28.8, p <0.01 for presence, beta coefficient = 3.59 +/- 0.88 [SE], p = 0.009 for extent) and individual risk factors, including age, gender, smoking, body mass index, hypertension, diabetes, hyperlipidemia, and clinical coronary disease (odds ratio 8.4, 95% confidence interval 1.7 to 42.5, p = 0.008 for presence, beta coefficient = 2.35 +/- 0.86 [SE], p = 0.007 for extent). Similarly, MS was independently associated with calcified and noncalcified plaques individually. In conclusion, MS was independently associated with the presence and extent of both calcified and noncalcified coronary atherosclerotic plaques detected using multidetector computed tomography. These data may explain the higher cardiovascular risk in these patients and may lay the foundation for studies to determine whether such information may improve risk stratification.     

Association of Tube Voltage With Plaque Composition on Coronary CT Angiography: Results From PARADIGM Registry

ObjectivesThis study sought to investigate the impact of low tube voltage scanning heterogeneity of coronary luminal attenuation on plaque quantification and characterization with coronary computed tomography angiography (CCTA).BackgroundThe impact of low tube voltage and coronary luminal attenuation on quantitative coronary plaque remains uncertain.MethodsA total of 1,236 consecutive patients (age: 60 ± 9 years; 41% female) who underwent serial CCTA at an interval of ≥2 years were included from an international registry. Patients with prior revascularization or nonanalyzable coronary CTAs were excluded. Total coronary plaque volume was assessed and subclassified based on specific Hounsfield unit (HU) threshold: necrotic core, fibrofatty plaque, and fibrous plaque and dense calcium. Luminal attenuation was measured in the aorta.ResultsWith increasing luminal HU (<350, 350-500, and >500 HU), percent calcified plaque was increased (16%, 27%, and 40% in the median; P < 0.001), and fibrofatty plaque (26%, 13%, and 4%; P < 0.001) and necrotic core (1.6%, 0.3%, and 0.0%; P < 0.001) were decreased. Higher tube voltage scanning (80, 100, and 120 kV) resulted in decreasing luminal attenuation (689 ± 135, 497 ± 89, and 391 ± 73 HU; P < 0.001) and calcified plaque volume (59%, 34%, and 23%; P < 0.001) and increased fibrofatty plaque (3%, 9%, and 18%; P < 0.001) and necrotic core (0.2%, 0.1%, and 0.6%; P < 0.001). Mediation analysis showed that the impact of 100 kV on plaque composition, compared with 120 kV, was primarily caused by an indirect effect through blood pool attenuation. Tube voltage scanning of 80 kV maintained a direct effect on fibrofatty plaque and necrotic core in addition to an indirect effect through the luminal attenuation.ConclusionsLow tube voltage usage affected plaque morphology, mainly through an increase in luminal HU with a resultant increase in calcified plaque and a reduction in fibrofatty and necrotic core. These findings should be considered as CCTA-based plaque measures are being used to guide medical management and, in particular, when being used as a measure of treatment response. (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angiography Imaging [PARADIGM]; NCT02803411)     

Imaging of coronary atherosclerosis using computed tomography: Current status and future directions

Computed tomography (CT) imaging of the coronary arteries, using either electron beam tomography (EBT) or multidetector row CT (MDCT), offers two possibilities to assess coronary atherosclerosis. Without injection of contrast agent, coronary calcifications can be detected and quantified. Their presence and extent correlates to the presence and amount of coronary atherosclerotic plaque. Prospective studies have demonstrated a high predictive value concerning the occurrence of coronary artery disease events and overall mortality. An emerging consensus seems to indicate that calcium imaging may be clinically useful in patients at intermediate risk for coronary artery disease events as determined based on traditional risk factors. In addition, recent studies have shown that after injection of contrast agent and using high-resolution scan protocols, the visualization of noncalcified plaque is also possible with CT techniques. However, data on the accuracy of plaque detection, quantification of plaque volume, and characterization of plaque (eg, lipid-rich vs fibrous) is currently limited, and the prognostic significance of noncalcifed coronary atherosclerotic plaque detection is unclear.     

Relation of coronary plaque composition determined by 64-slice multidetector computed tomography in patients with suspected coronary heart disease

Sixty-four-slice multidetector row computed tomography is a noninvasive method of assessing coronary artery stenosis and plaque composition. The aim of this study was to clarify the relation between plaque composition and coronary heart disease. Three hundred sixty consecutive patients and 1,085 plaques were evaluated using 64-slice multidetector row computed tomography. On axial or cross-sectional multiplanar reconstruction images, 3 regions of interest were randomly selected within each plaque. Soft plaques and calcified plaques were defined as having computed tomographic densities <50 and >130 Hounsfield units, respectively. The association between coronary risk factors and plaque composition was analyzed. The number of plaques and the mean computed tomographic density of plaques were significantly higher in men than in women (p = 0.002 and p = 0.04, respectively). Coronary plaques were more frequent in patients with stroke, diabetes, hypertension, and dyslipidemia than in patients without these conditions (all p values <0.001). Calcified plaques were more frequent in patients with hypertension (p = 0.02), and patients with calcified plaques also had significantly lower low-density lipoprotein cholesterol levels (p <0.001). Soft plaques were more frequent in patients with dyslipidemia (p <0.001). Patients with soft plaques had significantly higher low-density lipoprotein cholesterol levels (p = 0.02) and lower high-density lipoprotein cholesterol levels (p <0.001) than those without soft plaques. In conclusion, 64-slice multidetector row computed tomography is a useful noninvasive method for quantifying coronary plaques.     

Accuracy of nonstenotic coronary atherosclerosis assessment by multi-detector computed tomography.

BACKGROUND: The ability to evaluate coronary stenosis using multi-detector computed tomography (MDCT) has been well discussed. In contrast, several studies demonstrated that the plaque burden measured by intravascular ultrasound (IVUS) has a relationship to the risk of cardiovascular events. the accuracy of MDCT was studied to determine plaque and vessel size compared with IVUS. METHODS AND RESULTS: Fifty-six proximal lesions (American College of Cardiology/American Heart Association classification: segment 1, 5, 6) from 33 patients were assessed using MDCT and IVUS. The plaque and vessel area were measured from the cross-sectional image using both MDCT and IVUS. Eight coronary artery lesions with motion artifacts and heavily calcified plaques were excluded from the analysis. The vessel and lumen size evaluated using MDCT were closely correlated with those evaluated by IVUS (R(2)=0.614, 0.750 respectively). Furthermore, there was a strong correlation between percentage plaque area assessed by MDCT and IVUS (R(2)=0.824). CONCLUSION: MDCT can noninvasively quantify coronary atherosclerotic plaque with good correlation compared with IVUS in patients with atherosclerosis.     

Accuracy of multidetector spiral computed tomography in identifying and differentiating the composition of coronary atherosclerotic plaques: a comparative study with intracoronary ultrasound

OBJECTIVES: We evaluated the accuracy of contrast-enhanced multidetector spiral computed tomography (MDCT) for the noninvasive detection and classification of coronary plaques and compared it with intracoronary ultrasound (ICUS). BACKGROUND: Noninvasive determination of plaque composition and plaque burden may be important to improve risk stratification and to monitor progression of coronary atherosclerosis. METHODS: We included 46 consecutive patients with a distinctive risk profile, who were investigated by ICUS (Goldvision, 20 MHz, Jomed Inc., Rancho Cordova, California). Due to the inability to slow the heart rate below 65 beats/min (n = 7) and due to renal insufficiency (n = 2), nine of 46 consecutive patients could not be studied by MDCT (Sensation 16, Siemens, Forchheim, Germany). RESULTS: In the remaining 37 patients, 68 vessels were investigated by ICUS, and 58 of these vessels were visualized by MDCT with image quality sufficient for analysis. In these vessels that were divided in 3-mm sections, MDCT correctly classified 62 of 80 (78%) sections containing hypoechoic plaque areas, 87 of 112 (78%) sections containing hyperechoic plaque areas, and 150 of 158 (95%) sections containing calcified plaque tissue. In 484 of 525 (92%) sections, atherosclerotic lesions were correctly excluded. The MDCT-derived density measurements within coronary lesions revealed significantly different values for hypoechoic (49 HU [Hounsfield Units] +/- 22), hyperechoic (91 HU +/- 22), and calcified plaques (391 HU +/- 156, p < 0.02). CONCLUSIONS: This study demonstrates that, in the case of diagnostic image quality, contrast-enhanced MDCT permits an accurate identification of coronary plaques and that computed tomography density values measured within plaques reflect echogenity and plaque composition.     

Noninvasive tissue characterization of coronary arterial plaque by 16-slice computed tomography in acute coronary syndrome

Noninvasive characterization of coronary plaques is challenging for cardiologists. The authors' goal was to explore the clinical feasibility of newly developed 16-slice computed tomography (CT) in tissue characterization of coronary arterial plaques in patients with acute coronary syndrome. Sixteen patients with acute coronary syndrome underwent 16-slice CT (Aquillion, Toshiba) and coronary arteriography with intravascular ultrasound (IVUS) within 7 days. Twenty-three plaques were classified by IVUS according to plaque echogenicity: 6 soft plaques, 11 intermediate plaques, and 6 calcified plaques. Mean (+/- SD) CT numbers (Hounsfield units [HU]) of these 3 types of plaques were 50.6 +/-14.8 HU, 131 +/-21.0 HU, and 721 +/-231 HU, respectively. Sixteen-slice CT facilitates noninvasive tissue characterization of coronary arterial plaques.