Evaluation of coronary artery remodeling in patients with acute coronary syndrome and stable angina by multislice computed tomography

Using artificial intelligence to study atherosclerosis from computed tomography imaging: A state-of-the-art review of the current literature

With the enormous progress in the field of cardiovascular imaging in recent years, computed tomography (CT) has become readily available to phenotype atherosclerotic coronary artery disease. New analytical methods using artificial intelligence (AI) enable the analysis of complex phenotypic information of atherosclerotic plaques. In particular, deep learning-based approaches using convolutional neural networks (CNNs) facilitate tasks such as lesion detection, segmentation, and classification. New radiotranscriptomic techniques even capture underlying bio-histochemical processes through higher-order structural analysis of voxels on CT images. In the near future, the international large-scale Oxford Risk Factors And Non-invasive Imaging (ORFAN) study will provide a powerful platform for testing and validating prognostic AI-based models. The goal is the transition of these new approaches from research settings into a clinical workflow. In this review, we present an overview of existing AI-based techniques with focus on imaging biomarkers to determine the degree of coronary inflammation, coronary plaques, and the associated risk. Further, current limitations using AI-based approaches as well as the priorities to address these challenges will be discussed. This will pave the way for an AI-enabled risk assessment tool to detect vulnerable atherosclerotic plaques and to guide treatment strategies for patients.

Characteristics of high-risk coronary plaques identified by computed tomographic angiography and associated prognosis: a systematic review and meta-analysis

To clarify the potential role of coronary computed tomographic angiography (CCTA) in characterizing and prognosticating high-risk coronary plaques. A systematic review and meta-analysis were conducted to compare high-risk vs. low-risk plaques and culprit vs. non-culprit lesions in patients with acute coronary syndrome (ACS) vs. stable angina (SA). High-risk plaques were defined by at least one of the following features: non-calcified plaque (NCP), the presence of spotty calcified plaque (SCP), or increased remodelling index (RI). Results of included studies were pooled as odds ratios (OR) or weighted mean differences (WMD) with 95% confidence interval (CI). Eighteen eligible studies provided data to compare plaque types, plaque volume, and RI. Six studies provided data on ACS events in vulnerable high-risk vs. low-risk calcified plaques after 35 ± 2 months of follow-up. ACS patients had significantly higher number of NCP and SCP compared with SA patients with OR = 1.96 (1.47-2.60; 95% CI) P = 0.0001 and OR = 4.5 (2.98-6.83; 95% CI) P = 0.0001, respectively. Total plaque volume in ACS was not larger than SA: WMD = 22.9 (-22.1 to 67; 95% CI) mm(3), P = 0.32, but NCP volume was significantly larger: WMD = 28.8 (10.9-46.7; 95% CI) mm(3), P = 0.002. RI was higher in culprit lesions in ACS compared with SA and compared with non-culprit lesions in ACS patients: WMD = 0.48 (0.25-0.70; 95% CI) P = 0.0001 and 0.19 (0.07-0.30) P = 0.0001, respectively. The associated risk of future ACS was significantly higher in high-risk than in low-risk plaques: OR = 12.1 (5.24-28.1; 95% CI) P = 0.0001. CCTA can non-invasively characterize high-risk vulnerable coronary plaques and can predict future ACS events in patients with high-risk plaques.

Progression of coronary artery disease. Experience with computed tomography

Coronary artery disease (CAD) begins with asymptomatic atherosclerotic changes in the vessel wall. Gradual or abrupt progression of some of these early lesions eventually leads to symptomatic luminal narrowing. Coronary computed tomography angiography (CTA) allows for a minimally invasive assessment of these wall changes and of the severity of luminal narrowing, and is thus an attractive method for assessing progression/regression. However, because of the associated radiation exposure and concern about false-positive findings, CTA is not recommended as a clinical screening test. Owing to the significantly lower spatial resolution compared with invasive modalities, its application as a tool for clinical progression/regression trials is limited. Therefore, while there are extensive data from both CT coronary artery calcium scoring and CTA studies demonstrating the prognostic value of luminal stenosis as well as the extent and characteristics of plaque, data describing progression/regression are limited.

Association of neutrophil/lymphocyte ratio with obstructive coronary artery disease and coronary artery calcium score detected by multislice computed tomography in type 2 diabetes mellitus patients

OBJECTIVE

The aim of the present study was to investigate the association of neutrophil/lymphocyte ratio (NLR) with coronary artery calcium score (CACS) and obstructive coronary artery disease (CAD) detected by multislice computed tomography (MSCT) angiography in type 2 diabetes mellitus (T2DM) patients.

METHODS

Two hundred and ninety-two T2DM patients, who were either asymptomatic or symptomatic (but noncharacteristic) for coronary artery disease (CAD) and underwent MSCT angiography in our clinic between May 2009 and June 2014, were enrolled. All patients were divided into two groups according to their mean NLR values. Patients with NLR ≤2.05 were assigned to Group 1 and patients with NLR >2.05 were assigned to Group 2. The association of NLR with CACS and obstructive CAD, which were detected by MSCT angiography, was investigated in T2DM patients.

RESULTS

According to the Agatston scoring method, the mean CACS was 129.5±209.8 Au in Group 1 and 290.3±399.6 Au in Group 2 (P<0.001). Obstructive CAD was detected in 40 (26.8%) patients in Group 1 and in 56 (39.2%) patients in Group 2 (P<0.05, P<0.021).

CONCLUSION

The rate of obstructive CAD was significantly higher in the T2DM patients with NLR >2.05 than that in the T2DM patients with NLR ≤2.05. In addition, the CACS was also significantly higher in the T2DM patients with NLR >2.05 than that in the T2DM patients with NLR ≤2.05.

Cardiac CT: atherosclerosis to acute coronary syndrome

Coronary computed tomographic angiography (CCTA) is a robust non-invasive method to assess coronary artery disease (CAD). Qualitative and quantitative assessment of atherosclerotic coronary stenosis with CCTA has been favourably compared with invasive coronary angiography (ICA) and intravascular ultrasound (IVUS). Importantly, it allows the study of preclinical stages of atherosclerotic disease, may help improve risk stratification and monitor the progressive course of the disease. The diagnostic accuracy of CCTA in the assessment of coronary artery bypass grafts (CABG) is excellent and the constantly improving technology is making the evaluation of stents feasible. Novel techniques are being developed to assess the functional significance of coronary stenosis. The excellent negative predictive value of CCTA in ruling out disease enables early and safe discharge of patients with suspected acute coronary syndromes (ACS) in the Emergency Department (ED). In addition, CCTA is useful in predicting clinical outcomes based on the extent of coronary atherosclerosis and also based on individual plaque characteristics such as low attenuation plaque (LAP), positive remodelling and spotty calcification. In this article, we review the role of CCTA in the detection of coronary atherosclerosis in native vessels, stented vessels, calcified arteries and grafts; the assessment of plaque progression, evaluation of chest pain in the ED, assessment of functional significance of stenosis and the prognostic significance of CCTA.

Role of computed tomography for diagnosis and risk stratification of patients with suspected or known coronary artery disease

Cardiac computed tomographic angiography (CCTA) has emerged as a powerful imaging modality for the detection and prognostication of individuals with suspected coronary artery disease. Because calcification of coronary plaque occurs in proportion to the total atheroma volume, the initial diagnostic potential of CCTA focused on the identification and quantification of coronary calcium in low- to intermediate-risk individuals, a finding that tracks precisely with the risk of incident adverse clinical events. Beyond noncontrast detection of coronary calcium, CCTA using iodinated contrast yields incremental information about the degree and distribution of coronary plaques and stenosis, as well as vessel wall morphology and atherosclerotic plaque features. This additive information offers the promise of CCTA to provide a more comprehensive view of total atherosclerotic burden because it relates to myocardial ischemia and future adverse clinical events. Furthermore, emerging data suggest the prognostic and diagnostic importance of stenosis severity detection and atherosclerotic plaque features described by CCTA including positive remodeling, low-attenuation plaque, and spotty calcification, which have been associated with the vulnerability of plaque. We report a summary of the evidence supporting the role of CCTA in the detection of subclinical and clinical coronary artery disease in both asymptomatic and symptomatic patients and discuss the potential of CCTA to augment the identification of at-risk individuals. CCTA and coronary artery calcium scoring offer the ability to improve risk stratification, discrimination, and reclassification of the risk in patients with suspected coronary artery disease and to noninvasively determine the measures of stenosis severity and atherosclerotic plaque features.

Relationship between carotid artery remodeling and plaque vulnerability with T1-weighted magnetic resonance imaging

BACKGROUND

The aim of this study was to validate the relationship between carotid artery remodeling defined as the carotid remodeling index (CRI) and plaque vulnerability by comparing the degree of outward remodeling calculated using 3-dimensional inversion recovery-based T1-weighted imaging (magnetization-prepared rapid acquisition gradient echo [MPRAGE]) with the symptomatology and histology of plaques extracted during carotid endarterectomy.

METHODS

Sixty-one patients with 50% stenosis or more (North American Symptomatic Carotid Endarterectomy Trial criteria) were included. The average rate of stenosis was 79.8%. The CRI was determined by measuring the external cross-sectional vessel area (CSVA) at the maximum stenosis of the internal carotid artery (ICA) and dividing it by the external CSVA at the distal ICA (unaffected by atherosclerosis) using MPRAGE imaging.

RESULTS

The CRI was significantly higher in symptomatic patients compared with asymptomatic patients (1.98±.26 versus 1.68±.24, P<.0001). A higher CRI positively correlated with the necrotic core area (r=.57, P<.0001) and negatively correlated with the fibrous cap thickness (r=-.33, P=.01). It was also significantly associated with severe intraplaque hemorrhage (P<.0001) and the prevalence of cap inflammation with macrophage (P=.03) and lymphocyte (P=.01) infiltration.

CONCLUSIONS

The larger outward remodeling of the carotid artery on MPRAGE imaging had symptomatic carotid plaques and histologically vulnerable plaques. This study indicates that MPRAGE imaging is useful for the assessment of carotid artery remodeling.

Three-dimensional computed tomography angiography for the preoperative evaluation of coronary artery disease in lung cancer patients

BACKGROUND

The number of elderly patients undergoing surgery for lung cancer is increasing. In this study, we assessed the usefulness of three-dimensional computed tomographicangiography (3D-CTA) for the detection of coronary disease in the elderly before surgical intervention for lung cancer.

METHODS

One hundred twenty patients admitted to our institution for lung cancer resection were enrolled in the study. 3D-CTA was performed in all 120 patients.

RESULTS

Seventy-one patients had normal findings, and forty-nine patients showed coronary stenosis on 3D-CTA examination. Among the latter 49 patients, 24 with slight stenosis underwent lung tumor resection, 23 had coronary angiography for severe stenosis before lung surgery and 2 were not eligible for lung resection because of very severe coronary stenosis. The diagnostic value of 3D-CTA was better than conventional CT.

CONCLUSIONS

This study suggests the usefulness of 3D-CTA for the preoperative diagnosis of coronary ischemic disease in elderly lung cancer patients.

Intravascular ultrasound analysis of plaque characteristics and postpercutaneous coronary intervention catheterization outcomes according to the remodeling pattern in narrowed saphenous vein grafts

We assessed the plaque characteristics and postpercutaneous coronary intervention (PCI) outcome according to the remodeling pattern (positive remodeling [PR], n = 113; and intermediate/negative remodeling [IR/NR], n = 198) in 311 saphenous vein graft lesions using intravascular ultrasound. The remodeling index was the ratio of the lesion site saphenous vein graft area to the mean of the proximal and distal references (PR/remodeling index >1.05, IR 0.95 to 1.05, and NR <0.95). Tissue prolapse was defined as tissue extrusion through the stent strut after PCI, and the tissue prolapse volume was calculated by subtracting the lumen volume from the stent volume. The presence of hypoechoic plaque (59% vs 36%, p = 0.001), plaque rupture (26% vs 16%, p = 0.042), multiple plaque rupture (12% vs 5%, p = 0.020), and an intraluminal mass (59% vs 41%, p = 0.002) were more common in the PR lesions than in the IR/NR lesions. The plaque cavity area was significantly greater in the PR lesions than in the IR/NR lesions (0.83 ± 1.43 mm(2) vs 0.42 ± 1.07 mm(2), p = 0.009). Post-PCI no-reflow (19% vs 9%, p = 0.019) and post-PCI tissue prolapse (53% vs 27%, p <0.001) were observed more frequently, and the tissue prolapse volume was significantly greater after PCI for PR lesions than for IR/NR lesions (0.86 ± 1.30 mm(3) vs 0.34 ± 0.74 mm(3), p <0.001). PR was the independent predictor of post-PCI no-reflow (odds ratio 2.58, 95% confidence interval 1.25 to 5.64, p = 0.040) and post-PCI tissue prolapse (odds ratio 2.45, 95% confidence interval 1.46 to 5.41, p = 0.045). In conclusion, saphenous vein graft lesions with PR have vulnerable plaque and are associated with no-reflow and tissue prolapse after PCI.

Positive remodeling is associated with vulnerable coronary plaque components regardless of clinical presentation: virtual histology-intravascular ultrasound analysis

OBJECTIVE

We used virtual histology-intravascular ultrasound (VH-IVUS) to evaluate the relation between coronary artery remodeling pattern and plaque components in 1133 patients.

METHODS

We divided the patients into two groups according to the remodeling pattern as positive remodeling (PR, remodeling index>1.05) (n=192) and intermediate remodeling (IR, remodeling index ≤ 1.05 and ≥ 0.95)/negative remodeling (NR, remodeling index<0.95) (n=941). VH-IVUS analysis classified the color-coded tissue into four major components: green (fibrotic, FT); yellow-green (fibro-fatty); white (dense calcium); and red (necrotic core, NC). Thin-cap fibroatheroma (TCFA) was defined as focal, NC-rich (≥ 10% of the cross-sectional area) plaques being in contact with the lumen in a plaque burden ≥ 40%.

RESULTS

At the minimum lumen site, PR group had greater plaque plus media area (12.8 ± 4.9 vs. 9.9 ± 3.8mm(2), p<0.001) and greater %NC area (21.7 ± 12.3 vs. 18.2 ± 11.6%, p<0.001) and smaller %FT area (57.0 ± 14.5 vs. 59.4 ± 14.6%, p=0.037) compared with IR/NR group. PR group had greater plaque volume (188 ± 150 vs. 135 ± 130 mm(3), p<0.001) and greater %NC volume (19.1 ± 9.6 vs. 16.6 ± 9.2%, p=0.001) and smaller %FT volume (58.3 ± 11.7 vs. 60.6 ± 11.0%, p=0.009) compared with IR/NR group. PR group had more TCFA compared with IR/NR group (21% vs. 13%, p=0.006). Similar findings about plaque components were observed in terms of greater %NC volume and smaller %FT volume in PR group compared with IR/NR group in patients with both acute coronary syndrome and stable angina.

CONCLUSIONS

VH-IVUS analysis demonstrates that PR was associated with more vulnerable plaque components compared with IR/NR regardless of their clinical presentation.

Coronary atherosclerosis imaging by coronary CT angiography: current status, correlation with intravascular interrogation and meta-analysis

Coronary computed tomography angiography (CTA) allows coronary artery visualization and the detection of coronary stenoses. In addition; it has been suggested as a novel, noninvasive modality for coronary atherosclerotic plaque detection, characterization, and quantification. Emerging data show that coronary CTA-based semiquantitative plaque characterization and quantification are sufficiently reproducible for clinical purposes, and fully quantitative approaches may be appropriate for use in clinical trials. Furthermore, several lines of investigation have validated plaque imaging by coronary CTA against other imaging modalities such as intravascular ultrasound/"virtual histology" and optical coherence tomography, and there are emerging data using biochemical modalities such as near-infrared spectroscopy. Finally, clinical validation in patients with acute coronary syndrome and in the outpatient setting has shown incremental value of CTA-based plaque characterization for the prediction of major cardiovascular events. With recent developments in image acquisition and reconstruction technologies, coronary CTA can be performed with relatively low radiation exposure. With further technological innovation and clinical research, coronary CTA may become an important tool in the quest to identify vulnerable plaques and the at-risk patient.

Atherogenic dyslipidemia and cardiovascular risk in children with nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease is now regarded as the most common form of chronic liver disease in adults and children. The close association between nonalcoholic fatty liver disease (NAFLD) and the metabolic syndrome has been extensively described. Moreover, a growing body of evidence suggest that NAFLD by itself confers a substantial cardiovascular risk independent of the other components of the metabolic syndrome. Given the significant potential for morbidity and mortality in these patients, and the large proportion of both pediatric and adult population affected, it is important that we clearly define the overall risk, identify early predictors for cardiovascular disease progression, and establish management strategies. In this article, we will focus on current data linking NAFLD and the severity of liver damage present in children with cardiovascular risk.

Plaque vulnerability in internal carotid arteries with positive remodeling

BACKGROUND

This study aimed to evaluate the efficacy of assessing positive remodeling for predicting future stroke events in the internal carotid artery. We therefore assessed narrowing of the carotid artery lumen using multidetector-row computer tomography (MDCT) angiography and carotid plaque characteristics using black-blood (BB) magnetic resonance (MR).

METHODS

We retrospectively selected 17 symptomatic and 11 asymptomatic lesions with luminal narrowing >50%. We compared remodeling parameters of luminal stenosis (remodeling ratio, RR/remodeling index, RI) using MDCT and MR intensities of atherosclerotic plaque contents using the BB technique (relative signal intensity, rSI). We also confirmed the validity of the relationship between MR intensity and atherosclerotic plaque contents by histology. The levels of biological markers related to vessel atherosclerosis were measured.

RESULTS

Plaque lesions with positive remodeling in carotid arteries were associated with a significantly higher prevalence of stroke compared with plaques with negative remodeling (p < 0.05). Radiologic and histologic analyses determined that plaques with positive remodeling had higher signal intensities (with respect to their lipid-rich content or to hemorrhage) compared with negative remodeling (correlation coefficients: RI and rSI, r = 0.41, p < 0.05; RR and rSI, r = 0.50, p < 0.05). Levels of biological markers, including high-sensitivity C-reactive protein, hemoglobin A1C, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol, were not useful for predicting stroke events.

CONCLUSIONS

The results of this study suggest that the combined analysis of RR, RI and rSI could potentially help to predict future stroke events.

Assessment of coronary stenosis, plaque burden and remodeling by multidetector computed tomography in patients referred for suspected coronary artery disease

AIMS

To compare multidetector computed tomography (MDCT) with intravascular ultrasound (IVUS) and invasive quantitative coronary angiography (QCA) for assessment of coronary lesions in patients referred for suspected coronary artery disease (CAD).

METHODS AND RESULTS

We studied 57 patients (48 men; mean age: 63 ± 10 years) who underwent 64-slice MDCT because of atypical chest pain, stable angina, or ECG abnormalities and were diagnosed with CAD. All patients subsequently underwent QCA and IVUS. We analyzed 102 coronary lesions using the three techniques. Measurements of luminal area stenosis and cross-sectional area by MDCT (72.9 ± 7.0% and 4.5 ± 1.8 mm, respectively) were in good agreement with those by IVUS [72.7 ± 6.7% and 4.5 ± 1.6 mm, respectively; Lin's concordance correlation coefficient r = 0.847; 95% confidence interval (CI) = 0.792-0.902 and r = 0.931; 95% CI = 0.906-0.956, respectively] but not QCA (r = 0.115; 95% CI = 0.040-0.189 and r = 0.433; 95% CI = 0.291-0.576, respectively). Plaque cross-sectional area and plaque volume measured by MDCT (12.4 ± 3.8 mm and 104.7 ± 52.8 microl, respectively) were in good agreement with those by IVUS (12.2 ± 3.7 mm and 102.8 ± 54.1 microl; r = 0.913; 95% CI = 0.880-0.945 and r = 0.979; 95% CI = 0.969-0.990, respectively). Remodeling index measurements by MDCT (1.22 ± 0.22) were in good agreement with those by IVUS (r = 0.876; 95% CI = 0.831-0.922). Positive remodeling occurred in 63% of stenoses.

CONCLUSION

MDCT allows accurate noninvasive assessment of coronary stenosis, plaque burden and remodeling in patients referred for suspected CAD. Positive remodeling is a frequent finding in stable lesions.

Noninvasive imaging of the vulnerable atherosclerotic plaque

Atherosclerosis is an inflammatory disease, complicated by progressively increasing atherosclerotic plaques that eventually may rupture. Plaque rupture is a major cause of cardiovascular events, such as unstable angina, myocardial infarction, and stroke. A number of noninvasive imaging techniques have been developed to evaluate the vascular wall in an attempt to identify so-called vulnerable atherosclerotic plaques that are prone to rupture. The purpose of the present review is to systematically investigate the accuracy of noninvasive imaging techniques in the identification of plaque components and morphologic characteristics associated with plaque vulnerability, assessing their clinical and diagnostic value.

The culprit lesion score on multi-detector computed tomography can detect vulnerable coronary artery plaque

Vulnerable plaques are characterized by large lipid cores, positive remodeling and small coronary calcium deposits. Multi-detector computed tomography (MDCT) has recently been shown to be able to characterize coronary artery plaques. The aim of this study was to evaluate culprit coronary lesions for differentiating acute coronary syndrome (ACS) from stable angina pectoris (SAP) using MDCT. 64-slice MDCT was conducted on 71 patients (ACS: 35, SAP: 36). The culprit coronary lesions were assessed according to the type and plaque attenuation (PA) of the plaque and the remodeling index (RI) as the ratio of the lesion and the reference area. The culprit lesion score (CLS) was defined as the sum of every score as 1.2 for a PA ≤ 60 Hounsfield units (HU), 1.1 for a RI ≥ 1.05 and 1.2 for a non-calcified or spotty calcification. More spotty calcification (95.0% vs. 23.1%, P < 0.001), a lower PA (40.17 ± 20.08 HU vs. 96.96 ± 58.19 HU, respectively, P < 0.001) and a higher RI (1.44 ± 0.43 vs. 0.90 ± 0.44, respectively, P < 0.001) were observed in the ACS patients. Also, the CLS of the ACS patients was significantly higher than that of the SAP patients (3.07 ± 0.63 vs. 1.18 ± 1.12, respectively, P < 0.001). A CLS more than 2.0 helped us to differentiate ACS from SAP with a sensitivity of 97.1% and a specificity of 67.6%. The CLS might be a useful tool for differentiating ACS from SAP.

Non-invasive assessment and clinical strategy of stable coronary artery disease by magnetic resonance imaging, multislice computed tomography and myocardial perfusion SPECT

Coronary multislice computed tomography (MSCT) angiography and magnetic resonance angiography (MRA) have emerged as new diagnostic techniques that allow direct visualization of the coronary artery. These new modalities have both advantages and disadvantages concerning radiation exposure, the use of contrast medium, ability of visualizing heavily calcified artery lumens, and spatial and temporal resolution. However, these modalities only provide anatomical information of the coronary artery. Functional assessment of the severity of coronary artery disease (CAD) is essential for the management of patients with known or suspected CAD in practical clinical settings. Myocardial perfusion single-photon emission computed tomography is thought to be the most suitable diagnostic procedure for the determination of therapeutic strategy when coronary MSCT and MRA show significant and also insignificant coronary artery lesions. (Circ J 2010; 74: 34 - 40).

Characterization of hyperintense plaque with noncontrast T(1)-weighted cardiac magnetic resonance coronary plaque imaging: comparison with multislice computed tomography and intravascular ultrasound

OBJECTIVES

This study sought to characterize coronary hyperintense plaques (HIP) using noncontrast T(1)-weighted imaging (T1WI) in cardiac magnetic resonance, which was then compared with multislice computed tomography and intravascular ultrasound.

BACKGROUND

Carotid plaque components such as intraplaque hemorrhages and/or lipid-rich necrotic cores can be detected as HIP by noncontrast T1WI. Although coronary HIPs have been successfully detected using this technique, the properties of hyperintense signals in coronary plaques have not yet been systematically evaluated.

METHODS

Thirty-eight lesions from 37 patients with angina pectoris who demonstrated >70% coronary stenosis on multislice computed tomography were evaluated by noncontrast T1WI using a 1.5-T magnetic resonance imager, and 25 lesions were evaluated by intravascular ultrasound. Signal intensity of coronary plaque to cardiac muscle ratio >1.0 was defined as HIP. We divided 25 lesions into the 2 groups, according to the presence or absence of HIP: HIP (n = 18) and non-HIP (n = 7) groups.

RESULTS

In comparison with the non-HIP group, the HIP group demonstrated significantly higher coronary plaque to cardiac muscle ratio (1.7 +/- 0.7 vs. 0.9 +/- 0.1, p < 0.01), higher frequency of positive remodeling as observed by both multislice computed tomography (89% vs. 0%, p<0.0001) and intravascular ultrasound (94% vs. 14%, p < 0.001) and ultrasound attenuation (100% vs. 14.3%, p < 0.0001). The frequency of spotty calcification tended to be higher in HIP (89% vs. 50%, p = 0.079). The HIP group also exhibited a significantly lower computed tomography density (-23.2 +/- 20.7 Hounsfield units [HU] vs. 9.6 +/- 20.5 HU, p < 0.01). In addition, the incidence of transient slow-flow phenomena was significantly higher in the HIP group than in the non-HIP group (83% vs. 14%, p < 0.01).

CONCLUSIONS

The typical HIP case was associated with ultrasound attenuation, positive remodeling, remarkably low computed tomography density, and a high incidence of slow-flow phenomena. Noncontrast T1WI in cardiac magnetic resonance imaging may be useful for the assessment of coronary plaque characterization in patients with coronary artery disease.

Comparison of frequency of calcified versus non-calcified coronary lesions by computed tomographic angiography in patients with stable versus unstable angina pectoris

Computed tomographic coronary angiography (CTCA) can noninvasively identify calcified and noncalcified coronary plaques. The aim of this study was to compare the phenotypes of all plaques and of culprit plaques between patients with unstable angina pectoris (UAP) and those with stable angina pectoris (SAP), because plaque characteristics may differ between these patients. In 110 patients with UAP and 189 with SAP from a multicenter study comparing 64-slice CTCA with conventional coronary angiography, the number and phenotypes (noncalcified, mixed, and calcified) of coronary plaques were compared. In a subanalysis in 50 patients with UAP and 64 with SAP, culprit plaque characteristics, including culprit plaque cross-sectional area relative to total vessel cross-sectional area, culprit plaque length, remodeling index, and spotty calcification, were determined. Odds ratios for the presence of UAP, adjusted for clinical variables and the total number of plaques, were calculated for plaque characteristics on CTCA. Although the number of plaques was similar for patients with UAP and those with SAP, plaques in patients with UAP were more frequently noncalcified than in patients with SAP. The odds ratio for UAP was 1.3 (95% confidence interval [CI] 1.1 to 1.5) per noncalcified plaque. In the culprit plaque subanalysis, odds ratios for UAP were 0.99 (95% CI 0.96 to 1.01) per millimeter culprit plaque length, 2.7 (95% CI 1.2 to 6.4) for noncalcified culprit plaque, and 1.06 (95% CI 0.99 to 1.13) per percentage relative culprit plaque cross-sectional area. No significant relation was found between remodeling index or spotty calcification and UAP. In conclusion, noncalcified plaques and large noncalcified culprit plaques are more frequently found in patients with UAP than in those with SAP.

Evaluation of vulnerable coronary plaques and non-alcoholic fatty liver disease (NAFLD) by 64-detector multislice computed tomography (MSCT)

BACKGROUND

Multislice computed tomography (MSCT) permits direct visualization of not only coronary artery stenosis but also the characteristics of plaques in patients with coronary artery disease (CAD). Also, because of its potential to be a novel risk factor for cardiovascular disease, interest in non-alcoholic fatty liver disease (NAFLD) is increasing.

METHODS AND RESULTS

Participants comprised 298 consecutive patients who received MSCT to diagnose CAD. Patients with an alcohol intake exceeding 20 g/day or with a history of known liver disease were excluded from the study. Liver steatosis and 4 coronary artery findings, including remodeling lesions, lipid core plaques, calcified plaques and narrowing of lumen, were assessed. Liver steatosis was evaluated by computed tomography density of the liver and spleen. In the study, NAFLD was defined as having a liver and spleen (L:S) ratio of <1.1. The L:S ratios of patients with remodeling lesions or lipid core plaques were significantly lower than those without. NAFLD was related significantly to those findings, but there was no correlation between calcified plaques, narrowing of lumen and L:S ratios. Adjusted odds ratio of NAFLD for remodeling lesions was 2.41 (95% confidence interval (CI), 1.24-4.67; p=0.009), and those for lipid core lesions was 2.29 (95% CI, 1.15-4.56; p=0.018).

CONCLUSION

NAFLD is a novel risk factor for vulnerable plaques.

Non-invasive assessment of plaque rupture by 64-slice multidetector computed tomography--comparison with intravascular ultrasound

BACKGROUND

Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS). Multidetector computed tomography (MDCT) allows the non-invasive assessment of coronary artery stenosis and plaque properties. In this study, we investigated whether 64-slice MDCT could non-invasively detect a plaque rupture in patients with de novo angina.

METHODS AND RESULTS

The study population comprised 67 patients with de novo angina. All patients underwent contrast-enhanced 64-slice MDCT and intravascular ultrasound (IVUS). Patients were divided into a plaque rupture group (n=27) and a non-rupture group (n=40) based on the IVUS. The 64-slice MDCT revealed that the prevalence of an ulcer-like enhancement space (37% vs 5%, p<0.01), a ring-like sign (41% vs 18%, p=0.04), in the plaque rupture group was higher than those in the non-rupture group. Maximum plaque thickness (2.1+/-0.9 mm vs 1.6+/-1.0 mm, p=0.04), outer vessel area (17.6+/-4.9 mm2 vs 13.4+/-5.0 mm2, p<0.01), percentage plaque area (82.3+/-9.1% vs 73.4+/-15.7%, p=0.01), and remodeling index (1.11+/-0.18 vs 1.01+/-0.15, p=0.04) of the plaque rupture group were all significantly larger than those of the non-rupture group.

CONCLUSIONS

The 64-slice MDCT can identify differences in lesion morphologies between ruptured plaques and non-ruptured plaques. From our results, the 64-slice MDCT might provide a useful tool for the non-invasive detection of plaque rupture.

Imaging of coronary artery fistulas by multidetector computed tomography: is multidetector computed tomography sensitive?

BACKGROUND

Coronary angiography is the gold standard for diagnosing coronary artery fistulas (CAFs). Multidetector computed tomography (MDCT) is a recently developed imaging technique for detecting coronary artery stenosis, coronary artery anomalies, and coronary artery fistulas and their courses.

OBJECTIVE

We aimed to determine accuracy or sensitivity of MDCT in patients having CAF.

METHOD

We evaluated 13 patients with 15 CAFs detected earlier by coronary angiography. MDCT was carried out on all patients and the results were compared with coronary angiography, following which, sensitivity of MDCT was detected.

RESULTS

Eleven of 15 CAFs were shown on MDCT and the overall sensitivity of MDCT was found to be 73%. Seven of 8 CAFs that coursed between two vascular structures were detected and the sensitivity of MDCT in this group was found to be 87%. However, the sensitivity of 58% of MDCT in patients with fistula coursing between coronary arteries and cardiac chambers was found.

CONCLUSION

Although coronary angiography is the gold standard diagnostic test for detection of CAF, MDCT may be an alternative test, especially, for CAF coursing between vascular structures, to detect origin, course, and the drainage site of fistula through its excellent spatial resolution and ability to show relationship of anatomic structures.

Relationship between degree of remodeling and CT attenuation of plaque in coronary atherosclerotic lesions: An in-vivo analysis by multi-detector computed tomography

Multi-detector CT (MDCT) permits non-invasive visualization of the coronary arteries. Coronary plaque can be visualized, and earlier studies have indicated that the CT attenuation measured in atherosclerotic plaques is influenced by plaque composition. Also, MDCT has been shown to permit assessment of remodeling of coronary atherosclerotic lesions. It is assumed that both lipid-rich plaques and those that display positive remodeling are more prone to rupture and erosion. We thus evaluated the relationship between remodeling and CT attenuation of coronary atherosclerotic plaque by MDCT.

METHODS

Seventy-six patients were investigated by contrast-enhanced 64-slice CT. One-hundred twelve atherosclerotic lesions without substantial calcification and visualized with high image quality were selected. Multiplanar reconstructions orthogonal to the coronary artery were rendered at the lesion and the proximal reference site. Cross-sectional vessel areas were measured to determine the remodeling index (RI: lesion vessel area/reference vessel area) and the CT attenuation of plaque was measured by fitting a region of interest to the plaque area. CT attenuation of plaque was correlated to the presence of positive remodeling index (RI>1.05).

RESULTS

The mean cross-sectional vessel area in the lesion was 0.25+/-0.08 cm(2), the mean reference vessel area was 0.22+/-0.09 cm(2). The mean CT attenuation of the atherosclerotic plaque in the lesions was 71+/-26 HU. CT attenuation of plaque was significantly lower in 72 lesions that displayed positive remodeling (59+/-22 HU) than in 40 lesions with no or with negative remodeling (91+/-20 HU, p<0.001).

CONCLUSIONS

Positive remodeling of coronary atherosclerotic lesions correlates to lower CT attenuation of plaque, which has been demonstrated to be associated with lipid-rich plaque. Both characteristics indicate increased risk for plaque rupture and subsequent events and could thus prove useful when the use of CT imaging for the detection of "vulnerable plaque" is considered.

Anomalous coronary arteries in adults detected by multislice computed tomography: presentation of cases from multicenter registry and review of the literature

Anomalous coronary arteries are a rare condition, but they may cause myocardial ischemia, heart failure, and sudden death. We evaluated the prevalence and multislice computed tomographic (MSCT) findings of anomalous coronary arteries in a large number of patients from the multicenter registry. At four institutes, 29 (0.74%) out of 3910 patients were found to have anomalous coronary arteries by MSCT. They consisted of 15 patients with anomalous origins of the right coronary artery, 1 with right-sided origin of the left circumflex artery, 1 with right-sided origin of the left main coronary artery, 2 with double right coronary arteries, 2 with the absence of the left circumflex artery, 1 with absence of the right coronary artery, 6 with coronary artery fistulas, and 1 with Bland-White-Garland syndrome. Multislice computed tomography findings were consistent with those obtained by conventional coronary angiography in all 14 patients undergoing both diagnostic procedures. Multislice computed tomography permits three-dimensional comprehension of coronary arteries, which is suitable for the diagnosis of anomalous coronary arteries.

The case in favor of screening for coronary artery disease with coronary CT angiography

Coronary computed tomographic angiography is leading a technologic revolution in the field of cardiac imaging. For the first time, it is possible to image the wall of the coronary artery noninvasively to assess plaque burden, characterize plaque, and assess the degree of stenosis. This paper explores the possibility of using coronary computed tomographic angiography as a screening tool. Key screening examination elements, the pros and cons of screening, the limitations of current technology, and potential pitfalls are discussed.

Prognostic Value of Myocardial Perfusion Single-Photon Emission Computed Tomography for the Prediction of Future Cardiac Events in a Japanese Population A Middle-Term Follow-up Study

BACKGROUND

The prognostic value of rest 201Tl/stress (99m)Tc-tetrofosmin myocardial perfusion single-photon emission computed tomography (SPECT) for the prediction of future hard cardiac events, including acute myocardial infarction (AMI), unstable angina (UAP) and cardiac death, and the implications for risk stratification has not yet been defined in a Japanese population.

METHODS AND RESULTS

The 1,988 patients who underwent rest 201Tl/stress (99m)Tc-tetrofosmin SPECT were identified and followed up for the occurrence of AMI, UAP and cardiac death. The mean follow-up interval was 26.9+/-15.8 months. The 142 patients were revascularized within 60 days after SPECT and they were censored from the prognostic analysis. Summed stress score (SSS), summed rest score and summed difference score (SDS) were calculated using a 5-point scoring (Normal: 0, No uptake: 4) and a 20-segment model; 22 cases of myocardial infarction, 31 of UAP and 22 cardiac deaths occurred (1.2%, 1.7% and 1.2%, respectively). Multivariate Cox regression analysis showed that hypertension (Wald 6.37, p<0.05) and SDS (Wald 8.77, p<0.01) were independent predictors of AMI and UAP. Advanced age (Wald 16.0, p<0.001), SSS (Wald 10.9, p<0.01) and SDS (Wald 4.58, p<0.05) were independent predictors of cardiac death.

CONCLUSION

Myocardial perfusion SPECT yields prognostic information toward the identification of acute coronary syndrome and cardiac death.

Cardiac CT: coronary arteries and beyond

Multi-detector-row computed tomography (MDCT) has emerged as a rapidly developing method for non-invasive imaging of the heart. An understanding of ECG synchronization, contrast material administration, patient preparation and image post-processing is needed to optimize image quality. The basic technical principles and essentials of these technical basics are described here. Correctly applied cardiac MDCT allows imaging of the coronary arteries including coronary anatomy and stenosis detection. The same is true for evaluation of coronary artery bypass grafts and, to some extent, coronary artery stents. While quantification of total calcified plaque burden has been long established, coronary MDCT allows assessing plaque morphology and constitution. Recent approaches go beyond the coronaries and include evaluation of left ventricular function at rest and myocardial viability. In combination with experimental approaches for assessing aortic valve function and myocardial perfusion imaging, cardiac MDCT offers the potential for a comprehensive examination of the heart using a single breath-hold examination.

Clinical Significance of the Coronary Calcification Score by Multidetector Row Computed Tomography for the Evaluation of Coronary Stenosis in Japanese Patients

BACKGROUND

The coronary artery calcification (CAC) score measured by multidetector row computed tomography (MDCT) has emerged as a marker for predicting coronary artery disease (CAD). To evaluate the clinical significance of the CAC score, coronary artery stenosis as assessed by coronary angiography (CAG) was compared with the CAC score determined by MDCT, risk factors and medications.

METHODS AND RESULTS

Subjects included 374 consecutive patients who underwent ECG-gate CT angiography using MDCT. The accuracy in patients with a CAC score >or=400 was 84%, and significantly lower than that in patients with a CAC score =0. In addition 92 patients (68 males, 24 females; mean age, 63+/-11 years) who underwent both MDCT and CAG within a 1-month period were selected for further investigation. Patients with significant coronary stenosis had a significantly higher CAC score than those without stenosis. In addition, a higher number of stenosed vessels was associated with a higher CAC score. The subjects were divided into 3 groups according to the CAC score: low (0-12), intermediate (13-444) and high (>or=445). The CAC score was significantly associated with age, and plasma levels of total cholesterol and hemoglobinA1c, and logistic regression analysis revealed that significant coronary stenosis as assessed by CAG was most closely correlated with the CAC score (p=0.03).

CONCLUSIONS

The CAC score determined by MDCT can predict CAD independent of other factors, such as age, metabolic diseases and medications, when coronary stenosis can not be diagnosed because of severe calcification.

Evaluation of coronary stents in vitro with CT angiography: effect of stent diameter, convolution kernel, and vessel orientation to the z-axis

BACKGROUND

The aims of the present study were to assess the effect of the stent diameter, convolution kernel, and vessel orientation to the z-axis on the evaluation of coronary stents, in vitro with computed tomography (CT) angiography.

METHODS AND RESULTS

Seven vascular models (2 models without stenosis, 2 with obstruction, and 3 with stenosis) with an approximate inner diameter of 3 or 4 mm, filled with contrast material (79 or 330 HU) were scanned with a 16-detector CT. The diameter measurement of the stent lumen and stenosis evaluation were both done in an orientation parallel to the z-axis of the scanner using 4 convolution kernels. The measured diameters of the stented lumen were 47-57% and 36-45% smaller than the actual inner diameter of the 3- and 4-mm diameter models, respectively. The diameter measurement of the stent lumen and visualization of the in-stent stenosis were improved by using convolution kernels with higher spatial resolution. The in-stent artifacts were evaluated in 4 orientations (0 degrees , 30 degrees , 60 degrees , 90 degrees ) to the z-axis. The artifact was the minimum in 0 degrees to the z-axis, and the maximum in 90 degrees .

CONCLUSION

Visualization of the lumen of a stent by CT is affected by its diameter, convolution kernel, and vessel orientation to the z-axis, and these factors should be taken into consideration in the stent evaluation.

Computed tomography assessment of the regression of an atherosclerotic coronary artery plaque

Multislice spiral computed tomography (MSCT) permits the noninvasive visualization of coronary artery stenoses and occlusions, as well as atherosclerotic plaques, in patients with coronary artery disease. This report describes a patient with stable angina pectoris in whom the regression of the plaque and coronary artery remodeling was documented by serial MSCT.

Missense mutations resulting in type 1 lissencephaly

Proper human brain formation is dependent upon the integrated activity of multiple genes. Malfunctioning of key proteins results in brain developmental abnormalities. Mutation(s) in the LIS1 gene or the X-linked gene doublecortin (DCX) results in a spectrum of disorders including lissencephaly, or "smooth brain", and subcortical band heterotopia, or "doublecortex". Here, we will focus on a particular subset of missense mutations in these two genes and their effect on protein structure and function.

Impact of Preinterventional Arterial Remodeling on In-Stent Neointimal Hyperplasia and In-Stent Restenosis After Coronary Stent Implantation-An Intravascular Ultrasound Study-

BACKGROUND

Patterns of arterial remodeling during the course of plaque development have been shown to play an important role in both the progression of de novo atherosclerosis and in the restenotic process following coronary intervention. The aim of the present prospective study was to evaluate the effect of pre-interventional arterial remodeling on in-stent neointimal hyperplasia (NIH) and in-stent restenosis (ISR) after stenting.

METHODS AND RESULTS

Pre-interventional arterial remodeling was assessed in 85 native coronary lesions by using intravascular ultrasound (IVUS). The remodeling index (RI) was 1.09+/-0.20 in the positive remodeling (PR)/intermediate remodeling (IR) group and 0.84+/-0.12 in the negative remodeling (NR) group. The plaque plus media cross sectional area (P&M CSA) at pre-intervention and NIH CSA at follow-up in the minimal lumen CSA were significantly larger in the PR/IR group (9.2+/-2.9 mm2 vs 6.2+/-1.8 mm2, 3.3+/-1.2 mm2 vs 1.5+/-0.9 mm2; p = 0.001, p = 0.001, respectively). On 3-dimensional analysis of IVUS images at follow-up, the lumen volume was significantly smaller in the PR/IR group than that in the NR group (62+/-15 mm3 vs 75 +/-20 mm3; p = 0.001), and neointima hyperplasia volume was significantly larger in the PR/IR group than that in the NR group (46+/-15 mm3 vs 26+/-10 mm3; p = 0.001). A significant positive correlation was found between pre-interventional RI and follow-up NIH CSA (r = 0.25, p = 0.022). The incidence of ISR and repeat intervention was significantly higher in the PR/IR group (30.8% vs 18.2%, 28.8% vs 15.2%; p = 0.032, 0.035, respectively).

CONCLUSION

Measuring pre-interventional arterial remodeling patterns by IVUS may be helpful to stratify lesions at high-risk of ISR.

Detection of Anomalous Origins of the Coronary Artery by Means of Multislice Computed Tomography

BACKGROUND

Anomalous origins of the coronary artery are rare, but may cause myocardial ischemia and sudden death. Thus, their reliable identification is crucial for any imaging method that attempts coronary artery visualization and of those available multislice computed tomography (MSCT), which provides excellent spatial resolution, may be the most promising.

METHODS AND RESULTS

In consecutive 1,153 patients, MSCT identified 5 patients (0.43 %) with an anomalous origin of the coronary artery. The left circumflex artery (LCX) originated from the right sinus of Valsalva in 1 patient, and the right coronary artery originated from the left sinus of Valsalva and coursed between the aortic root and the pulmonary artery in 3 patients. In 1 patient, MSCT identified the absence of the LCX and high-grade atherosclerotic stenosis in the right coronary artery.

CONCLUSION

MSCT can detect the anomalous origin and course of the coronary artery in relation to the great vessels. It is also useful for identifying atherosclerotic coronary artery disease superimposed on the anomalous vascular system.