CT of coronary artery disease

Temporal Relationship-Aware Treadmill Exercise Test Analysis Network for Coronary Artery Disease Diagnosis

The treadmill exercise test (TET) serves as a non-invasive method for the diagnosis of coronary artery disease (CAD). Despite its widespread use, TET reports are susceptible to external influences, heightening the risk of misdiagnosis and underdiagnosis. In this paper, we propose a novel automatic CAD diagnosis approach. The proposed approach introduces a customized preprocessing method to obtain clear electrocardiograms (ECGs) from individual TET reports. Additionally, it presents TETDiaNet, a novel neural network designed to explore the temporal relationships within TET ECGs. Central to TETDiaNet is the TETDia block, which mimics clinicians' diagnostic processes to extract essential diagnostic information. This block encompasses an intra-state contextual learning module and an inter-state contextual learning module, modeling the temporal relationships within a single state and between states, respectively. These two modules help the TETDia block to capture effective diagnosis information by exploring the temporal relationships within TET ECGs. Furthermore, we establish a new TET dataset named TET4CAD for CAD diagnosis. It contains simplified TET reports for 192 CAD patients and 224 non-CAD patients, and each patient undergoes coronary angiography for labeling. Experimental results on TET4CAD underscore the superior performance of the proposed approach, highlighting the discriminative value of the temporal relationships within TET ECGs for CAD diagnosis.

Uterine arcuate artery calcification as a potential marker of cardiovascular risk-a preliminary study

OBJECTIVE

Atherosclerotic cardiovascular disease is the most common cause of death in postmenopausal women. As this is a progressive disease, it is important to identify markers at an early stage during the subclinical period. Arterial calcifications are an indicator of overall atherosclerotic disease and therefore may be used as a marker for the estimation of future atherosclerotic cardiovascular events. The aims of this study are to investigate the relationship between uterine myometrial calcification (UMC) and carotid artery intima-media thickness (CIMT) and to evaluate whether UMC can be a predictive marker for the estimation of future atherosclerotic cardiovascular risk in asymptomatic postmenopausal women.

METHODS

In this cross-sectional study, we assessed 81 postmenopausal women without gynecological complaints for cardiovascular risk factors, UMC, and CIMT. Participants were divided into two risk groups according to their cardiovascular risk factors. The level of UMC was determined using a new scoring system, which was based on transvaginal ultrasonography. Demographic, clinical, and laboratory parameters, UMC scores, and measurements of CIMT were evaluated.

RESULTS

A moderately positive correlation was detected between CIMT and UMC scores (r = 0.62). There was a significant relationship between UMC scores and atherosclerotic cardiovascular risk; the risk of atherosclerosis was 15.4 times higher (OR: 15.4, 95% CI: 5.1-46.8; P = 0.001) in participants with a high UMC score (≥2). According to the multivariable logistic regression model adjusted by age and duration of menopause, the risk of cardiovascular atherosclerosis increased 27.8 fold for those with CIMT of 0.075 or greater (OR: 27.8, 95% CI: 5.3-147.1; P = 0.001) and 9.2 fold for those with a UMC score of 2 or greater (OR: 9.2, CI: 1.22-69.3; P = 0.032).

CONCLUSIONS

The presence of UMC has been identified as an independent predictive factor for atherosclerotic risk. Accordingly, considering UMC as an atherosclerotic cardiovascular risk factor may provide an opportunity to identify cardiovascular disease in asymptomatic postmenopausal women. When UMC is detected, women should be assessed for cardiovascular risk.

Differential Diagnosis of Fulminant Myocarditis and Acute Coronary Syndromes in the Case of Failure of Coronary Angiography: A Case Report

Fulminant myocarditis (FM) is a severe disease with a rapidly progressive and life-threatening course caused mainly by viral infection. The symptoms, laboratory findings, and presence of ECG changes resemble acute coronary syndrome. Therefore, coronary angiography is usually helpful in making the appropriate diagnosis. However, failure to obtain complete coronary artery images due to coronary artery anatomic variations poses a challenge for the diagnosis of FM. Here, we report a case of FM preliminarily diagnosed as acute coronary syndrome (ACS) due to the presence of coronary artery anomaly.

ECG-gated multislice Computed Tomography angiography as a comprehensive non-invasive imaging tool in patient with aortic coarctation

We describe a case of a 52-year-old-woman with aortic coarctation demonstrated by means of 40-slice MSCT angiography. Based on the information extracted from MSCT it was possible to display the anatomical configuration of the disease, the thoraco-abdominal collateral pathways. The best therapeutic approach was established on the basis of MSCT findings. MSCT is a reliable and comprehensive tool for the assessment of adult patients with aortic coarctation. (www.actabiomedica.it)

Arcuate artery calcification on transvaginal sonography may predict coronary artery heart disease

Atherosclerosis is a systematic disease affecting all arteries and is the most common cause of mortality. Our aim was to evaluate the predictive value of the presence of uterine arcuate artery calcification (AAC) for coronary heart disease (CHD) in women. Seventy women presenting with angina pectoris or a finding suggestive of cardiac ischaemia in non-invasive tests, scheduled for angiography between June 2014 and July 2015 were recruited in the study. One day before the coroner artery angiography, all of the patients were examined about the presence of AAC by transvaginal ultrasonography and were classified in the presence of CHD. CHD is classified as obstructive (obstruction >70%) or as non-obstructive (obstruction <70%) according to the severity of stenosis. The association of AAC is evaluated with the presence and severity of CHD that's diagnosed by angiography. CHD was present in 87.2% of women with positive for AAC and in 4.3% of who were negative for AAC (p = .001). AAC positive women were more likely to develop obstructive CHD than non-obstructive CHD (66.6% versus 30.9%, p = .001), respectively. Sensitivity and specificity of AAC for CHD were 97.6% and 78.5%, respectively. AAC detected by transvaginal ultrasound seems to have a strong association with both presences of CHD and the severity of disease. Impact statement What is already known on this subject? Atherosclerosis affecting all arteries is the primary cause of mortality and morbidity of coronary heart disease (CHD) (Lim et al. 2011). Uterine artery calcification and its association with atherosclerosis were first reported by Camiel et al. (1967). Ozdemir et al. (2016) found a correlation between carotid artery intima thickness and the presence of uterine arcuate artery calcification (AAC). What do the results of this study add? Very few studies have been performed in this area investigating the relationship of AAC and non-invasive predictors of atherosclerosis or the relationship between arterial calcifications and cardiovascular or systemic disease. Our study is the first to evaluate the correlation between AAC and CHD confirmed using coronary artery angiography at a high sensitivity rate (97.6%). What are the implications of these findings for clinical practice and/or further research? Our study presents an alternative, easy and non-invasive method for the prediction of subclinical CHD in clinical practice. From the view of a gynaecologist, cardiology consultation of patients with AAC detected by transvaginal ultrasonography during the routine gynaecologic examination may be useful and protective against serious cardiac problems. Thus, this study is of great importance in terms of predicting when the majority of CHD patients are asymptomatic or in the subclinical phase.

Low-Dose Coronary CT Angiography in Patients with Atrial Fibrillation: Comparison of Image Quality and Radiation Exposure with Two Different Approaches

RATIONALE AND OBJECTIVES

To evaluate image quality, coronary interpretability and radiation exposure of coronary CT angiography (CCTA) performed in patients with atrial fibrillation (AF) with the latest scanner generation, comparing two different technical approaches. A new scanner that combines a 0.23 mm spatial resolution, a new generation of iterative reconstruction, fast gantry rotation time and the intracycle motion-correction algorithm to improve the temporal resolution was recently introduced in the clinical field.

MATERIALS AND METHODS

We enrolled 105 consecutive patients with chronic AF who performed CCTA with a whole-heart coverage high-definition CT scanner (16-cm z-axis coverage with 256 detector rows, 0.28 s gantry rotation time). Five of them were excluded for impaired renal function. Patients were randomized between a double acquisition protocol (50 patients, group 1) or a single acquisition protocol (50 patients, group 2). The image quality, coronary segment interpretability and effective dose (ED) of CCTA were assessed.

RESULTS

The mean HR during the scan was 85.6±21 bpm in group 1 vs. 83.7±23 bpm in Group 2, respectively (p < ns). In group 2, overall image quality was high and comparable with that of group 1 (Likert scale =3.2 ± 1.4 vs. 3.3 ± 1.2, p = ns, in group 1 and 2, respectively). Coronary interpretability was high and similar between the two groups (97.5% and 97.1% in group 1 and 2, p = ns, respectively). Mean ED was significantly higher in group 1 than in group 2 (5.3 ± 1.8 mSv vs. 2.7 ± 0.7 mSv, p < 0.001).

CONCLUSION

The novel whole-heart coverage CT scanner allows to perform CCTA with a single-acquisition protocol with high image quality and low radiation exposure in AF patients.

The degree of hair graying as an independent risk marker for coronary artery disease, a CT coronary angiography study

BACKGROUND

Cardiovascular disease is a leading cause of death worldwide. Aging is an unavoidable coronary risk factor and is associated with dermatological signs that could be a marker for increased coronary risk. We tested the hypothesis that hair graying as a visible marker of aging is associated with risk of coronary artery disease (CAD) independent of chronological age.

METHODS

This cross-sectional study included 545 males who underwent a computed tomography coronary angiography (CTCA) for suspicious of CAD, patients were divided into subgroups according to the percentage of gray/white hairs (Hair Whitening Score, HWS: 1-5) and to the absence or presence of CAD.

RESULTS

CAD was prevalent in 80% of our studied population, 255 (46.8%) had 3 vessels disease with mean age of 53.2 ± 10.7 yrs. Hypertension, diabetes and dyslipidemia were more prevalent in CAD group (P = 0.001, P = 0.001, and P = 0.003, respectively). Patients with CAD had statistically significant higher HWS (32.1% vs 60.1%, p < 0.001) and significant coronary artery calcification (<0.001). Multivariate regression analysis showed that age (odds ratio (OR): 2.40, 95% confidence interval (CI): [1.31-4.39], p = 0.004), HWS (OR: 1.31, 95% CI: [1.09-1.57], p = 0.004), hypertension (OR: 1.63, 95% CI: [1.03-2.58], p = 0.036), and dyslipidemia (OR: 1.61, 95% CI: [1.02-2.54], p = 0.038) were independent predictors of the presence of atherosclerotic CAD, and only age (p < 0.001) was significantly associated with HWS.

CONCLUSIONS

Higher HWS was associated with increased coronary artery calcification and risk of CAD independent of chronological age and other established cardiovascular risk factors.

Selecting a CT scanner for cardiac imaging: the heart of the matter

Coronary angiography to assess the presence and degree of arterial stenosis is an examination now routinely performed on CT scanners. Although developments in CT technology over recent years have made great strides in improving the diagnostic accuracy of this technique, patients with certain characteristics can still be "difficult to image". The various groups will benefit from different technological enhancements depending on the type of challenge they present. Good temporal and spatial resolution, wide longitudinal (z-axis) detector coverage and high X-ray output are the key requirements of a successful CT coronary angiography (CTCA) scan. The requirement for optimal patient dose is a given. The different scanner models recommended for CTCA all excel in different aspects. The specification data presented here for these scanners and the explanation of the impact of the different features should help in making a more informed decision when selecting a scanner for CTCA.

Patient selection essential for computed tomography coronary angiography

OBJECTIVE

Computed tomography coronary angiography (CTCA) has become a commonly used imaging modality in patients with suspected anginal symptoms but also in asymptomatic populations. This practice has raised concerns due to potential high radiation exposure in terms of adequate benefit to risk profile.

DESIGN

Demographics and CTCA scan details were collected from a consecutive series of 586 patients referred to a single community radiology practice for a CTCA.

RESULTS

Of the 586 patients, 271 (46.2%) were women. Mean age was 58.3 standard deviation (SD) 12.2, range 15-90 years, body mass index (BMI) 28.6 SD 5.9 kg/m(2), and heart rate 60 SD 10 beats per minute. Mean total radiation was 4.79 SD 3.45 mSv (range 0.64-31.34). The mean radiation exposure in the lowest quartile of BMI and heart rate were 3.01 SD 1.84 mSv and 3.95 SD 2.72 mSv, compared to the highest 7.32 SD 3.51 mSv and 6.20 SD 4.38 mSv (p for trend <0.0001 in both).

CONCLUSION

The radiation exposure in this consecutive series of patients is low in general but patient selection for CTCA imaging appears to be paramount. Patients with a high BMI and especially with high heart rate receive a higher dose of radiation.

Prospectively ECG-Triggered Sequential Dual-Source Coronary CT Angiography in Patients with Atrial Fibrillation: Influence of Heart Rate on Image Quality and Evaluation of Diagnostic Accuracy

Objectives

To evaluate the effects of mean heart rate (HR) and heart rate variation (HRV) on image quality and diagnostic accuracy of prospectively ECG-triggered sequential dual-source coronary CT angiography (CCTA) in patients with atrial fibrillation (AF).

Methods

Eighty-five patients (49 women, 36 men; mean age 62.1±9.5 years) with persistent AF underwent prospectively ECG-triggered sequential second-generation dual-source CCTA. Tube current and voltage were adjusted according to body mass index (BMI) and iterative reconstruction was used. Image quality of coronary segments (four-point scale) and presence of significant stenosis (>50%) were evaluated. Diagnostic accuracy was analyzed in 30 of the 85 patients who underwent additional invasive coronary angiography (ICA).

Results

Only 8 of 1102 (0.7%) segments demonstrated poor image quality. No significant impact on image quality was found for mean HR (94.9±21.8 bpm; r=0.034, p=0.758; F=0.413, p=0.663) or HRV (67.5±22.8 bpm; r=0.097, p=0.377; F=0.111, p=0.895). On per-segment analysis, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 89.7% (26/29), 99.4% (355/357), 92.9% (26/28), and 99.2% (355/358), respectively, with excellent correlation (kappa=0.91) with ICA. Mean effective dose was 3.3±1.0 mSv.

Conclusions

Prospectively ECG-triggered sequential dual-source CCTA provides diagnostic image quality and good diagnostic accuracy for detection of coronary stenosis in AF patients without significant influence by HR or HRV.

Cardiac radiology: centenary review

During the past century, cardiac imaging technologies have revolutionized the diagnosis and treatment of acquired and congenital heart disease. Many important contributions to the field of cardiac imaging were initially reported in Radiology. The field developed from the early stages of cardiac imaging, including the use of coronary x-ray angiography and roentgen kymography, to nowadays the widely used echocardiographic, nuclear medicine, cardiac computed tomographic (CT), and magnetic resonance (MR) applications. It is surprising how many of these techniques were not recognized for their potential during their early inception. Some techniques were described in the literature but required many years to enter the clinical arena and presently continue to expand in terms of clinical application. The application of various CT and MR contrast agents for the diagnosis of myocardial ischemia is a case in point, as the utility of contrast agents continues to expand the noninvasive characterization of myocardium. The history of cardiac imaging has included a continuous process of advances in our understanding of the anatomy and physiology of the cardiovascular system, along with advances in imaging technology that continue to the present day.

Coronary vasodilation by the use of sublingual nitroglycerin using 64-slice dual-source coronary computed tomography angiography

BACKGROUND

Sublingual nitroglycerin capsules or spray is routinely used to treat anginal attacks and to maximally dilate the epicardial coronary arteries during coronary angiography. These dilated coronary vessels have an advantage, but increased heart rates were disadvantageous for coronary computed tomography angiography (CTA).

PURPOSE

The influence of applying nitroglycerin was analyzed regarding the coronary diameter, coronary luminal attenuation, evaluable number of coronary segments, heart rate (HR), HR variability, the optimal reconstruction phase, and image scoring of CTA in the same patients using a 64-slice dual-source CT.

METHODS AND SUBJECTS

Fifty-two patients with atypical chest pain underwent coronary CTA before and after the administration of sublingual nitroglycerin without heart rate control. The coronary diameter and luminal attenuation were measured on short-axial images in each coronary segment. The coronary vasodilation ratios (VRs) were calculated from the coronary diameters at the same location before and after the use of nitroglycerin. The local institutional review board approved this study and written informed consent was obtained from all the patients.

RESULTS

No significant differences were noted in the HR variability or optimal reconstruction phase, despite an increase in HR after the use of nitroglycerin. Nitroglycerin significantly enlarged the coronary artery diameter, and VRs of each coronary segment ranged from 7.54% to 22.26%. As compared with baseline coronary diameter, VRs of minor segments (16.91%) were significantly larger than those of major segments (11.35%), and the magnitude of VR correlated with the baseline coronary diameter (r=-0.48, p<0.001). Coronary luminal attenuation significantly increased due to additional administration of contrast material after the use of nitroglycerin (p<0.01), but no significant difference was noted in the image quality after the use of nitroglycerin.

CONCLUSION

Sublingual nitroglycerin significantly enlarged the coronary diameters, especially in peripheral small coronary arteries, and increased the evaluable number of coronary segments on coronary CTA.

Assessment of vascular contrast and wall motion of the aortic root and ascending aorta on MDCT angiography: dual-source high-pitch vs non-gated single-source acquisition schemes

OBJECTIVES

This retrospective study assessed whether dual-source high-pitch computed tomographic angiography (CTA) offered advantages over single-source standard-pitch techniques in the evaluation of the ascending aorta.

METHODS

Twenty patients who received both thoracic dual-source high-pitch and single-source standard-pitch CTAs within 1 year were assessed. Dual-source CTAs were performed; standard-pitch imaging used dose-modulated 120 kVp/150 mAs and 0.8 pitch compared with high-pitch protocols employing dose-modulated 120 kVp/250 mAs and 2.4 target pitch. Radiation dose was documented. Contrast-to-noise ratios (CNRs) at sinuses of the Valsalva (CNRValsalva) and ascending aorta (CNRAorta) were calculated. Dose/CNR for each technique was compared with paired t-tests. Motion at aortic valve, aortic root and ascending aorta were assessed with four-point scales and Mann-Whitney U tests; longitudinal extension of motion was compared with paired t-tests.

RESULTS

Significantly lower motion scores for high-pitch, compared with standard-pitch acquisitions for aortic annulus, 0 vs. 2, aortic root, 0 vs. 3, and ascending aorta, 0 vs. 2, were achieved. Significantly reduced longitudinal extension of motion at aortic root, 4.9 mm vs 15.7 mm, and ascending aorta, 4.9 mm vs 21.6 mm, was observed. Contrast was not impacted: CNRValsalva, 45.6 vs 46.3, and CNRAorta, 45.3 vs 47.1. CTDIvol was significantly decreased for high-pitch acquisitions, 13.9 mGy vs 15.8 mGy.

CONCLUSIONS

Dual-source high-pitch CTAs significantly decreased motion artefact without negatively impacting vascular contrast and radiation dose.

KEY POINTS

• Dual-source high-pitch CTA significantly decreased motion artefact of the ascending aorta. • Dual-source high-pitch CTA did not negatively impact on vascular contrast. • Dual-source high-pitch CTA significantly decreased radiation dose compared with single-source standard-pitch acquisitions.

Relationship between breast arterial calcification on mammography with CT Calcium scoring and coronary CT angiography results

Background:

Mammography as a non invasive method has been suggested to be helpful in predicting coronary artery disease. This study aimed to investigate whether presence and severity of breast artery calcification (BAC) on mammograms is associated with computed tomography coronary angiography (CTCA) finding such as coronary artery calcium (CAC) score and the severity of coronary artery stenosis.

Materials and Methods:

This cross-sectional study was performed on 150 women aged >40 years who were referred for CTCA. Women who had undergone screening mammography during the first year after CTCA entered the study. CAC score was determined and the severity of coronary artery stenosis was classified into normal, non-significant stenosis, or significant stenosis. Based on the severity of BAC, patients were also grouped into normal, mild, moderate, or severe groups. Then, the correlation between BAC severity and CAC score was determined. Patients with different BAC severity were also compared regarding the relative frequency of different grades of coronary artery stenosis.

Results:

Mean age of subjects with BAC (n: 35) was significantly higher than patients without BAC (n: 115) (68.03 ± 6.16 versus 54.36 ± 7.63 years, P < 0.0001). Although the relative frequency of different grades of coronary artery stenosis was significantly higher in women with BAC (P < 0.0001), after controlling for age, there was no significant difference between patients with different severity of BAC in the mean of CAC score (P: 0.09). In addition, the correlation between BAC severity and CAC score was not statistically significant (R: 0.09, P: 0.26).

Conclusion:

We concluded that presence and severity of BAC have no significant correlation with CAC score on CTCA.

Automatic detection of left and right ventricles from CTA enables efficient alignment of anatomy with myocardial perfusion data

BACKGROUND

Accurate alignment between cardiac CT angiographic studies (CTA) and nuclear perfusion images is crucial for improved diagnosis of coronary artery disease. This study evaluated in an animal model the accuracy of a CTA fully automated biventricular segmentation algorithm, a necessary step for automatic and thus efficient PET/CT alignment.

METHODS AND RESULTS

Twelve pigs with acute infarcts were imaged using Rb-82 PET and 64-slice CTA. Post-mortem myocardium mass measurements were obtained. Endocardial and epicardial myocardial boundaries were manually and automatically detected on the CTA and both segmentations used to perform PET/CT alignment. To assess the segmentation performance, image-based myocardial masses were compared to experimental data; the hand-traced profiles were used as a reference standard to assess the global and slice-by-slice robustness of the automated algorithm in extracting myocardium, LV, and RV. Mean distances between the automated and the manual 3D segmented surfaces were computed. Finally, differences in rotations and translations between the manual and automatic surfaces were estimated post-PET/CT alignment. The largest, smallest, and median distances between interactive and automatic surfaces averaged 1.2 ± 2.1, 0.2 ± 1.6, and 0.7 ± 1.9 mm. The average angular and translational differences in CT/PET alignments were 0.4°, -0.6°, and -2.3° about x, y, and z axes, and 1.8, -2.1, and 2.0 mm in x, y, and z directions.

CONCLUSIONS

Our automatic myocardial boundary detection algorithm creates surfaces from CTA that are similar in accuracy and provide similar alignments with PET as those obtained from interactive tracing. Specific difficulties in a reliable segmentation of the apex and base regions will require further improvements in the automated technique.

Multidetector-row computed tomography for noninvasive coronary imaging

Computed tomography (CT) permits cross-sectional imaging of the heart. Temporal and spatial resolutions of the technique have been insufficient to cover the heart without motion artefacts until the recent advent of multidetector systems with more than 16 detector rows. The modality is now suited for noninvasive imaging of the coronary arteries, producing detailed morphologic images of the entire coronary tree with upto 0.4 mm of spatial resolution, within a single short breath-hold duration. CT imaging goes beyond the delineation of the coronary lumen as provided by selective invasive angiography; the plaque burden of the coronary artery wall can be visualized directly, utilizing soft-tissue contrast and a high sensitivity even for the small calcifications that are present in hard plaque formations. Therefore, CT combines elements of catheterization angiography for lumen imaging and of intravascular ultrasound imaging for coronary wall imaging. However current CT technology is not yet able to compete with the temporal or spatial resolution of catheterization angiography nor does it provide the detailed spatial or contrast resolution of intravascular ultrasound imaging. At present, its use is therefore restricted to complementing the invasive modalities in appropriate indications. Although CT entails significantly less risk than the invasive procedures, the risks of radiation dose exposure and contrast agent application are not negligible. In the foreseeable future, if the current rate of technological advancement continues, CT may replace the invasive modalities in routine care for diagnostic purposes.

Advances in cardiac magnetic resonance imaging and computed tomography

Imaging evaluation of the heart encompasses structural evaluation of the chambers, valves and coronary arteries, and functional evaluation, including assessment of perfusion, wall motion and myocardial viability. Magnetic resonance imaging is well established for the structural and functional evaluation of the heart, and benefits from direct multiplanar image acquisition and a lack of ionizing radiation. Magnetic resonance imaging assessment of myocardial viability after myocardial infarction appears to be helpful in predicting benefit from revascularization procedures. Magnetic resonance imaging continues to hold promise as the least invasive method of coronary artery evaluation, and continuing developments are improving image quality and decreasing examination time. The development of cardiac-gating techniques for multidetector computed tomography has the potential to provide widespread availability of cardiac computed tomography. Short examination times and straightforward scanning procedures promise a convenient method for the examination of cardiac structure and function. However, this convenience must be balanced against radiation dose and contrast-media requirements when determining the appropriate use of cardiac computed tomography. Computed tomography coronary-calcium scoring can aid in the prediction of significant coronary events in all but the lowest-risk patients. The high negative-predictive value of computed tomography coronary angiography may allow some patients to avoid cardiac catheterization, but its role in the assessment of patients with moderate coronary atherosclerosis remains unclear. New software tools can assist in the complex and tedious analysis of the large volumes of data produced by these examinations.

Advances in the noninvasive evaluation of coronary artery disease with multislice computed tomography

Current noninvasive detection of coronary artery disease (CAD) is based on the demonstration of ischemia using stress-rest imaging, which is an indirect way of identifying CAD by demonstration of the hemodynamic consequences, rather than direct visualization of the obstructive lesions in the coronary arteries. Multislice computed tomography (MSCT) has recently emerged as an extremely rapidly developing noninvasive imaging modality, which allows anatomical imaging of the coronary arteries or noninvasive coronary angiography. In addition, total plaque burden, plaque morphology and (to some extent) plaque constitution can be assessed by MSCT. The technique also provides information on resting left ventricular systolic function, and possibly resting perfusion. Ideally, stress function and perfusion should also be evaluated, since this would allow detection of ischemia and would complete the picture of CAD. However, this is not routinely performed, since sequential acquisitions are associated with high radiation doses and thus pose a limitation for cardiovascular applications of MSCT. It is anticipated that, with a reduction in radiation, MSCT may become an important player in the diagnostic and prognostic work-up of patients with known or suspected CAD.

256-slice CT coronary angiography: in vivo dosimetry and technique optimization

PURPOSE

This study was undertaken to compare the different acquisition protocols available in a last-generation multislice computed tomography scanner used for cardiovascular studies, with particular attention to dosimetric aspects.

MATERIALS AND METHODS

Our study compared prospective and retrospective electrocardiographic-gating techniques for cardiac imaging. For each patient, we performed in vivo dose measurements, using Gafchromic film. We compared the effective dose values estimated from the experimental measurements and the dose data reported on the CT console. Image quality was also assessed.

RESULTS

Prospective acquisition allows for major dose savings compared to retrospective acquisition (mean effective dose, 4.5 mSv with prospective acquisition versus 27.5 mSv with retrospective acquisition). The agreement between the experimental and software-based dose estimates was excellent and showed below 10% of variation of the measured dose.

CONCLUSION

In patients with regular rhythm and a heart rate lower than 75 bpm, the prospective acquisition technique ensures adequate diagnostic results and allows for significant patient dose savings.

Optimization of K-edge imaging for vulnerable plaques using gold nanoparticles and energy resolved photon counting detectors: a simulation study

We investigated the effect of different imaging parameters, such as dose, beam energy, energy resolution and the number of energy bins, on the image quality of K-edge spectral computed tomography (CT) of gold nanoparticles (GNP) accumulated in an atherosclerotic plaque. A maximum likelihood technique was employed to estimate the concentration of GNP, which served as a targeted intravenous contrast material intended to detect the degree of the plaque's inflammation. The simulation studies used a single-slice parallel beam CT geometry with an x-ray beam energy ranging between 50 and 140 kVp. The synthetic phantoms included small (3 cm in diameter) cylinder and chest (33 × 24 cm(2)) phantoms, where both phantoms contained tissue, calcium and gold. In the simulation studies, GNP quantification and background (calcium and tissue) suppression tasks were pursued. The x-ray detection sensor was represented by an energy resolved photon counting detector (e.g., CdZnTe) with adjustable energy bins. Both ideal and more realistic (12% full width at half maximum (FWHM) energy resolution) implementations of the photon counting detector were simulated. The simulations were performed for the CdZnTe detector with a pixel pitch of 0.5-1 mm, which corresponds to a performance without significant charge sharing and cross-talk effects. The Rose model was employed to estimate the minimum detectable concentration of GNPs. A figure of merit (FOM) was used to optimize the x-ray beam energy (kVp) to achieve the highest signal-to-noise ratio with respect to the patient dose. As a result, the successful identification of gold and background suppression was demonstrated. The highest FOM was observed at the 125 kVp x-ray beam energy. The minimum detectable GNP concentration was determined to be approximately 1.06 µmol mL(-1) (0.21 mg mL(-1)) for an ideal detector and about 2.5 µmol mL(-1) (0.49 mg mL(-1)) for a more realistic (12% FWHM) detector. The studies show the optimal imaging parameters at the lowest patient dose using an energy resolved photon counting detector to image GNP in an atherosclerotic plaque.

The prevalence and clinical correlates of nonalcoholic fatty liver disease (NAFLD) in African Americans: the multiethnic study of atherosclerosis (MESA)

BACKGROUND AND AIMS

Nonalcoholic fatty liver disease (NAFLD) is the number one cause of liver disease in the United States. The prevalence rates in African Americans (AA), while significantly lower than other ethnic groups with similar known risk factors, have been quoted as high as 24 %. We aim to determine if the presence of NAFLD in African Americans is associated with lower triglyceride and/or higher HDL-c levels and if NAFLD risk factors in African Americans differ from other ethnic groups.

METHODS

A total of 3,056 participants of the Multi Ethnic Study of Atherosclerosis were included in this study. We utilized the baseline serum, anthropometric and radiographic measurements obtained between 2000 and 2002. NAFLD was defined as liver spleen ratio <1 from CT measurements.

RESULTS

The prevalence of NAFLD was and 11 % in AA. We found that age, education, triglyceride levels, HDL-c levels, waist circumference and HOMA-IR were independent correlates of NAFLD in this population. Among those with NAFLD, AA had significantly lower triglyceride levels than Hispanics [125 mg/dl (95 % CI 107-143) versus 192 mg/dl (95 % CI 169-215), p < 0.001] and Caucasians [185 mg/dl (95 % CI 161-209), p = 0.001]. Serum HDL-c was significantly higher in AA with NAFLD (47 mg/dl; 95 % CI 45-50) when compared to Hispanics (44 mg/dl; 95 % CI 43-66, p = 0.02) and Caucasians (44 mg/dl; 95 % CI 42-46, p = 0.02) with NAFLD.

CONCLUSIONS

This study demonstrated that the clinical correlates of NAFLD in African Americans are similar to the correlates of NAFLD in other ethnic groups. Our data also suggests that when evaluating African Americans for NAFLD risk, lower cutoff values should be used to define abnormal triglyceride levels.

Computerized tomography and 3-D rendering help to select surgical strategy in leiomyosarcoma of the inferior vena cava

Leiomyosarcoma of the inferior vena cava is a rare tumor that is usually fatal. The tumor may grow very slowly or occasionally very rapidly, shows extensive local invasion, and metastasizes more frequently than previously believed. Complete surgical resection remains the only potential curative therapeutic option. The aim of this study was to report the clinical experience in the management of a patient with leiomyosarcoma. A 65-year-old woman with a history of vague abdominal pain and leg swelling underwent computed tomography which demonstrated an occlusion of the inferior vena cava. The patient received a complete excision of the tumor without reconstruction and histological analysis confirmed the diagnosis of leiomyosarcoma type 1. At 3 years, the patient is still doing well with minimal leg edema and a contrast-enhanced CT demonstrates no evidence of recurrence locally or in distant sites. Leiomyosarcoma is a rare and aggressive tumor that presents with non-specific symptoms. Computerized tomography with 3-D reconstruction is a useful tool to define the presence and entity of the collateral circulation and therefore to decide on the surgical strategy. Resection probably offers the best opportunity for long-term survival.

Oxidative stress-induced telomeric erosion as a mechanism underlying airborne particulate matter-related cardiovascular disease

Particulate matter (PM) pollution is responsible for hundreds of thousands of deaths worldwide, the majority due to cardiovascular disease (CVD). While many potential pathophysiological mechanisms have been proposed, there is not yet a consensus as to which are most important in causing pollution-related morbidity/mortality. Nor is there consensus regarding which specific types of PM are most likely to affect public health in this regard. One toxicological mechanism linking exposure to airborne PM with CVD outcomes is oxidative stress, a contributor to the development of CVD risk factors including atherosclerosis. Recent work suggests that accelerated shortening of telomeres and, thus, early senescence of cells may be an important pathway by which oxidative stress may accelerate biological aging and the resultant development of age-related morbidity. This pathway may explain a significant proportion of PM-related adverse health outcomes, since shortened telomeres accelerate the progression of many diseases. There is limited but consistent evidence that vehicular emissions produce oxidative stress in humans. Given that oxidative stress is associated with accelerated erosion of telomeres, and that shortened telomeres are linked with acceleration of biological ageing and greater incidence of various age-related pathology, including CVD, it is hypothesized that associations noted between certain pollution types and sources and oxidative stress may reflect a mechanism by which these pollutants result in CVD-related morbidity and mortality, namely accelerated aging via enhanced erosion of telomeres. This paper reviews the literature providing links among oxidative stress, accelerated erosion of telomeres, CVD, and specific sources and types of air pollutants. If certain PM species/sources might be responsible for adverse health outcomes via the proposed mechanism, perhaps the pathway to reducing mortality/morbidity from PM would become clearer. Not only would pollution reduction imperatives be more focused, but interventions which could reduce oxidative stress would become all the more important.

Radiation dose and diagnostic accuracy of multidetector computed tomography for the detection of significant coronary artery stenoses: a meta-analysis

We conducted a meta-analysis evaluating the critical ratio between effective radiation dose (ED), feasibility (Fe) and diagnostic accuracy (Ac) of multidetector computed tomography (MDCT) for the detection of significant coronary artery disease. By using our predetermined criteria, we selected human studies published in English in which the ED and raw data of Ac vs. invasive coronary angiography in a segment based model were specified. Data from 31 studies including 3661 patients (mean age 61.9 ± 4.5 years, heart rate 62.5 ± 6.7 bpm) and 50,236 coronary artery segments were analysed and are reported. Overall, Fe, sensitivity, specificity, negative predictive value, positive predictive value, Ac and ED were 95%, 90%, 96%, 99%, 69%, 95% and 10.4 ± 5.4 mSv, respectively. Multivariate analysis showed that prospective ECG-gating (-8.8 mSv CI95% -13.4 to -4.3 mSv, p=0.001), dual-source (-3.7 mSv CI95% -7.9 to 0 mSv, p=0.05) and BMI-adapted scanning protocols (-4.5 mSv CI95% -8.7 to -2.7 mSv, p=0.03) were independent predictors of ED reduction. In patients with low heart rate, the best compromise between ED, Fe and Ac (2.5 mSv, 97% and 98%, respectively) was obtained combining prospective ECG-gating and BMI-adapted scanning protocols, while in patients with high heart rate the strategy associated with the best results (10 mSv, 98% and 97%, respectively) was the use of dual-source MDCT with retrospective ECG gating and modulation dose. In conclusion, careful selection of CT scanning protocols according to the patient's characteristics is critical for keeping the radiation exposure "as low as reasonably achievable" (ALARA) without impairing Fe and Ac.

Application of multi-slice spiral CT three-dimensional reconstruction technique in liver resection for hepatic carcinoma

Hepatic carcinoma is a very common disease across the world, and hepatic resection is still the best treatment. As the liver has complex anatomy and frequent vascular variations, it is of great importance to obtain some preoperative data, such as the position of liver cancer and its relationship with liver vessels and adjacent structures. Now, three-dimensional reconstruction technique allows to clearly show the relationship of the hepatic artery, portal vein, hepatic vein and tumor with surrounding strctures and accurately calculate the remnant liver volume, providing valuable preoperative imaging data for liver resection. This article will give an overview of three-dimensional reconstruction technique and discuss its ability to display liver vascularity, show the relationship between tumors and liver blood vessels, and predict liver resection volume.

Diagnostic value of 64-slice dual-source CT coronary angiography in patients with atrial fibrillation: comparison with invasive coronary angiography

Objective

We wanted to evaluate the image quality and diagnostic value of 64-slice dual-source computed tomography (DSCT) coronary angiography in patients with atrial fibrillation (Afib).

Materials and Methods

The coronary arteries of 22 Afib patients seen on DSCT were classified into 15 segments and the imaging quality (excellent, good, moderate and poor) and significant stenoses (≥ 50%) were evaluated by two radiologists who were blinded to the conventional coronary angiography (CAG) results. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for detecting important coronary artery stenosis were calculated. McNemar test was used to determine any significant difference between DSCT and CAG, and Cohen's Kappa statistics were calculated for the intermodality and interobserver agreement.

Results

The mean heart rate was 89 ± 8.3 bpm (range: 80-118 bpm). A range from 250 msec to 300 msec within the RR interval was the optimal reconstruction interval for the patients with Afib. The respective overall sensitivity, specificity, PPV and NPV values were 74%, 97%, 81% and 96% for reader 1 and 72%, 98%, 85% and 96% for reader 2. No significant difference between DSCT and CAG was found for detecting a significant stenosis (reader 1, p = 1.0; reader 2, p = 0.727). Cohen's Kappa statistics demonstrated good intermodality and interobserver agreement.

Conclusion

64-slice DSCT coronary angiography provides good image quality in patients with atrial fibrillation without the need for controlling the heart rate. DSCT can be used for ruling out significant stenosis in patients with atrial fibrillation with its high NPV for detecting in important stenosis.

Can non-calcified coronary artery plaques be detected on non-contrast CT calcium scoring studies?

RATIONALE AND OBJECTIVES

Coronary computed tomographic (CT) angiography has been shown to detect noncalcified coronary artery plaque. Depending on tissue composition, noncalcified plaque differs in CT attenuation from blood and epicardial fat. The aim of this study was to determine whether noncalcified plaque can be visually detected on non-contrast-enhanced CT calcium scoring studies.

MATERIALS AND METHODS

A total of 106 patients (40 women; mean age, 59 years) who underwent coronary calcium scoring, coronary CT angiography, and quantitative catheter angiography were prospectively investigated. Two blinded observers independently reviewed calcium scoring studies for positive vascular remodeling and hypoattenuation within the vessel wall, suggestive of noncalcified plaque. Findings on calcium scoring studies were compared with those on coronary CT angiography and quantitative catheter angiography.

RESULTS

The mean Agatston score was 515.8 ± 826.8. Overall interobserver agreement for the identification of noncalcified lesions was substantial (κ = 0.69). Observer 1 and observer 2 identified 21 and 17 patients, respectively, with 38 and 35 lesions suggestive of noncalcified plaque. Coronary CT angiography confirmed noncalcified plaque in 33 of 38 (86.8%; observer 1) and 31 of 35 (88.6%; observer 2) lesions. Thus, the overall positive predictive value for correct identification of noncalcified plaque on calcium scoring studies was 0.88, although overall sensitivity was low at 0.39.

CONCLUSIONS

Noncalcified plaque can be visually detected on calcium scoring studies. Review of calcium scoring studies for features of noncalcified plaque may enhance the identification of patients with more active disease and higher cardiovascular risk.

Cardiothoracic CT angiography: current contrast medium delivery strategies

OBJECTIVE

Over the last decade, rapid technologic evolution in CT has resulted in improved spatial and temporal resolution and acquisition speed, enabling cardiothoracic CT angiography to become a viable and effective noninvasive alternative in the diagnostic algorithm. These new technologic advances have imposed new challenges for the optimization of contrast medium delivery and image acquisition strategies.

CONCLUSION

Thorough understanding of contrast medium dynamics is essential for the design of effective acquisition and injection protocols. This article provides an overview of the fundamentals affecting contrast enhancement, emphasizing the modifications to contrast material delivery protocols required to optimize cardiothoracic CT angiography.

Life stress and atherosclerosis: a pathway through unhealthy lifestyle

OBJECTIVE

To examine the relationship between a general measure of chronic life stress and atherosclerosis among middle aged adults without clinical cardiovascular disease via pathways through unhealthy lifestyle characteristics.

METHODS

We conducted an analysis of The Multi-Ethnic Study of Atherosclerosis (MESA). The MESA collected in 2000 includes 5,773 participants, aged 45-84. We computed standard regression techniques to examine the relationship between life stress and atherosclerosis as well as path analysis with hypothesized paths from stress to atherosclerosis through unhealthy lifestyle. Our outcome was sub-clinical atherosclerosis measured as presence of coronary artery calcification (CAC).

RESULTS

A logistic regression adjusted for potential confounding variables along with the unhealthy lifestyle characteristics of smoking, excessive alcohol use, high caloric intake, sedentary lifestyle, and obesity yielded no significant relationship between chronic life stress (OR 0.93, 95% CI 0.80-1.08) and CAC. However, significant indirect pathways between chronic life stress and CAC through smoking (p = .007), and sedentary lifestyle (p = .03) and caloric intake (.002) through obesity were found.

CONCLUSIONS

These results suggest that life stress is related to atherosclerosis once paths of unhealthy coping behaviors are considered.

Imaging of coronary artery anomalies

Coronary artery anomalies (CAA) are uncommon congenital variations in coronary anatomy, occurring in 0.2% to 1.2% of the general population, the majority of which are detected incidentally and have little clinical significance. A minority of CAA, primarily due to an interarterial course, is clinically significant, and may present with symptoms of myocardial ischemia, malignant ventricular arrhythmias, and even sudden cardiac death. Until recently, CAA were primarily detected at catheter coronary angiography. With recent advances in multidetector computed tomography (CT) technology and the use of electrocardiographic gating, coronary CT angiography provides an exquisite omnidimensional display of the anomalous coronary arteries and their relation to the adjacent structures noninvasively, and is the diagnostic test of choice. Understanding CAA morphology and clinical significance of CAA is important for establishing a diagnosis, and is essential for appropriate patient management and treatment planning.

Multidetector CT of Aortic Dissection: A Pictorial Review

Aortic dissection is the most common acute emergency condition of the aorta and often has a fatal outcome. Outcome is determined by the type and extent of dissection and the presence of associated complications (eg, cerebral sequelae, aortic branch involvement, pericardial involvement, and visceral involvement), with early diagnosis and treatment being essential for improved prognosis. Aortic dissections are classified on the basis of the site of the intimal tear according to the Stanford classification system. Type A aortic dissection involves the ascending thoracic aorta and may extend into the descending aorta, whereas in a type B dissection the intimal tear is located distal to the left subclavian artery. Type A dissection typically requires urgent surgical intervention, whereas type B dissection can often be treated medically. Modern multidetector computed tomography (CT) is a fast, widely available imaging modality with high sensitivity and specificity. Multidetector CT allows the early recognition and characterization of aortic dissection as well as determination of the presence of any associated complications, findings that are essential for optimizing treatment and improving clinical outcomes.