Coronary Artery Imaging Research Articles

Chest pain in cardiac amyloidosis: occurrence, causes and prognostic significance

BackgroundChest pain is experienced by patients with cardiac amyloidosis (CA), but a systematic investigation of its frequency, underlying etiologies and clinical significance is lacking. MethodsClinical, echocardiographic, laboratory characteristics, available coronary arteries imaging and endomyocardial biopsy (EMB) findings of 174 patients with CA (n = 104 with transthyretin, ATTR; n = 70 with light chains, AL) were analyzed. ResultsChest pain was reported in 66 (38%) CA patients. Compared to those without, patients with chest pain had more frequently a history of coronary artery disease (CAD) (27% vs 15%, p = 0.048) and heart failure (HF) symptoms (62% vs 43%, p = 0.015), higher high sensitivity troponin I (hs-cTnI, 101 vs 65 ng/L, p = 0.032) and higher brain natriuretic peptide (597 vs 407 ng/L, p = 0.024). Among CA patients with chest pain undergoing coronary arteries imaging (n = 37), obstructive CAD was detected in 14 (38%), 13 of whom with ATTR-CA. Of these 37 patients, EMB was available in 10 and vascular/perivascular amyloid deposition was detected in 4/5 (80%) of AL-CA patients and 1/5 ATTR-CA. Among patients with suspected acute coronary syndrome (n = 22), obstructive CAD was detected in 9/17 (53%) ATTR-CA and 0/5 AL-CA; hs-cTnI levels were similar between those with and without obstructive CAD. During a follow-up of 17 (8–34) months, chest pain was a significant predictor of HF hospitalization (HR1.86, 95% CI 1.02–3.39, p = 0.042), even after adjustment for CA subtype and CAD. ConclusionChest pain is a common symptom in patients with CA, reflects a more advanced cardiac impairment and predicts future HF hospitalization. The etiology of chest pain seems to differ, with obstructive CAD more frequent in ATTR-CA whilst amyloid vascular/perivascular involvement more common in AL-CA.

Coronary stent imaging in photon counting computed Tomography: Optimization of reconstruction kernels in a phantom

PurposeImaging stents and in-stent stenosis remains a challenge in coronary computed tomography angiography (CCTA). In comparison to conventional Computed Tomography, Photon Counting CT (PCCT) provides decisive clinical advantages, among other things by providing low dose ultra-high resolution imaging of coronary arteries. This work investigates the image quality in CCTA using clinically established kernels and those optimized for the imaging of cardiac stents in PCCT, both for in-vitro stent imaging in 400 μm standard resolution mode (SRM) and 200 μm Ultra High Resolution Mode (UHR). MethodsBased on experimental scans, vascular reconstruction kernels (Bv56, Bv64, Bv72) were optimized. In an established phantom, 10 different coronary stents with 3 mm diameter were scanned in the first clinically available PCCT. Scans were reconstructed with clinically established and optimized kernels. Four readers measured visible stent lumen, performed ROI-based density measurements and rated image quality. ResultsRegarding the visible stent lumen, UHR is significantly superior to SRM (p < 0.001). In all levels, the optimized kernels are superior to the clinically established kernels (p < 0.001). One optimized kernel showed a significant reduction of noise compared to the clinically established kernels. Overall image quality is improved with optimized kernels. ConclusionsIn a phantom study PCCT UHR with optimized kernels for stent imaging significantly improves the ability to assess the in-stent lumen of small cardiac stents. We recommend using UHR with an optimized sharp vascular reconstruction kernel (Bv72uo) for imaging of cardiac stent.

Dual-Source Photon-Counting Computed Tomography-Part I: Clinical Overview of Cardiac CT and Coronary CT Angiography Applications.

The photon-counting detector (PCD) is a new computed tomography detector technology (photon-counting computed tomography, PCCT) that provides substantial benefits for cardiac and coronary artery imaging. Compared with conventional CT, PCCT has multi-energy capability, increased spatial resolution and soft tissue contrast with near-null electronic noise, reduced radiation exposure, and optimization of the use of contrast agents. This new technology promises to overcome several limitations of traditional cardiac and coronary CT angiography (CCT/CCTA) including reduction in blooming artifacts in heavy calcified coronary plaques or beam-hardening artifacts in patients with coronary stents, and a more precise assessment of the degree of stenosis and plaque characteristic thanks to its better spatial resolution. Another potential application of PCCT is the use of a double-contrast agent to characterize myocardial tissue. In this current overview of the existing PCCT literature, we describe the strengths, limitations, recent applications, and promising developments of employing PCCT technology in CCT.

Single Coronary Artery as a Rare Developmental Variant in Cardiac Computed Tomography Angiography

Cardiac computed tomography angiography (CCTA) is a non-invasive method for the diagnosis of coronary artery disease. In addition to the assessment of possible stenoses in the coronary arteries, this method also allows the assessment of other abnormalities of coronary and extracoronary heart structures. CCTA is the optimal method for assessing the relationship of coronary arteries to other anatomical structures; thus, it is used as a method of diagnosing developmental variants of coronary circulation. We present images of a single left coronary artery in a 384-slice CCTA in a 69-year-old Caucasian female patient with non-specific chest pain and low intermediate cardiovascular risk as an example of a rare developmental coronary variant. In conclusion, the importance of CCTA as a method of diagnosing developmental variations of the heart and vessels should be emphasized.

Proteomics and lipidomics in atherosclerotic cardiovascular disease risk prediction.

Given the limited accuracy of clinically used risk scores such as the Systematic COronary Risk Evaluation 2 system and the Second Manifestations of ARTerial disease 2 risk scores, novel risk algorithms determining an individual's susceptibility of future incident or recurrent atherosclerotic cardiovascular disease (ASCVD) risk are urgently needed. Due to major improvements in assay techniques, multimarker proteomic and lipidomic panels hold the promise to be reliably assessed in a high-throughput routine. Novel machine learning-based approaches have facilitated the use of this high-dimensional data resulting from these analyses for ASCVD risk prediction. More than a dozen of large-scale retrospective studies using different sets of biomarkers and different statistical methods have consistently demonstrated the additive prognostic value of these panels over traditionally used clinical risk scores. Prospective studies are needed to determine the clinical utility of a biomarker panel in clinical ASCVD risk stratification. When combined with the genetic predisposition captured with polygenic risk scores and the actual ASCVD phenotype observed with coronary artery imaging, proteomics and lipidomics can advance understanding of the complex multifactorial causes underlying an individual's ASCVD risk.

Virtual monochromatic images for coronary artery imaging with a spectral photon-counting CT in comparison to dual-layer CT systems: a phantom and a preliminary human study

ObjectivesTo evaluate the quality of virtual monochromatic images (VMIs) from spectral photon-counting CT (SPCCT) and two energy-integrating detector dual-energy CT (EID-DECT) scanners from the same manufacturer, for the coronary lumen.MethodsA 21-cm section of the Mercury v4.0 phantom was scanned using a cardiac CT protocol. VMIs from 40 to 90 keV were reconstructed using high-resolution (HR) parameters for EID-DECT and SPCCT (CB and HRB kernels at 0.67 mm slice thickness, respectively). Ultra-high-resolution (UHR) parameters were used in addition to SPCCT (detailed-2 kernel, 0.43 mm slice thickness). Noise-power-spectrum (NPS), task-based transfer function (TTF), and detectability index (d′) were computed for 2-mm-diameter lumen detection. In consensus, two radiologists analyzed the quality of the images from 8 patients who underwent coronary CTA on both CT systems.ResultsFor all keV images, fpeak, f50, and d′ were higher with SPCCT. The fpeak and f50 were higher with UHR-SPCCT with greater noise and lower d′ compared to those of the HR-SPCCT images. Noise magnitude was constant for all energy levels (keV) with both systems, and lower with HR images, and d′ decreased as keV decreased. Subjective analysis showed greater lumen sharpness and overall quality for HR and UHR-SPCCT images using all keV, with a greater difference at low keV compared to HR-EID-DECT images.ConclusionHR and UHR-SPCCT images gave greater detectability of the coronary lumen for 40 to 90 keV VMIs compared to two EID-DECT systems, with benefits of higher lumen sharpness and overall quality.Key Points• Compared with 2 dual-energy CT systems, spectral photon-counting CT (SPCCT) improved spatial resolution, noise texture, noise magnitude, and detectability of the coronary lumen.• Use of ultra-high-resolution parameters with SPCCT improved spatial resolution and noise texture and provided high detectability of the coronary lumen, despite an increase in noise magnitude.• In eight patients, radiologists found greater overall image quality with SPCCT for all virtual monochromatic images with a greater difference at low keV, compared with dual-energy CT systems.

Imaging of Left Main Coronary Artery; Untangling the Gordian Knot.

Left Main Coronary Artery (LMCA) disease is considered a standout manifestation of coronary artery disease (CAD), because it is accompanied by the highest mortality. Increased mortality is expected, because LMCA is responsible for supplying up to 80% of total blood flow to the left ventricle in a right-dominant coronary system. Due to the significant progress of biomedical technology, the modern drug-eluting stents have remarkably improved the prognosis of patients with LMCA disease treated invasively. In fact, numerous randomized trials provided similar results in one- and five-year survival of patients treated with percutaneous coronary interventions (PCI) -guided with optimal imaging and coronary artery bypass surgery (CABG). However, interventional treatment requires optimal imaging of the LMCA disease, such as intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The aim of this manuscript is to review the main pathophysiological characteristics, to present the imaging techniques of LMCA, and, last, to discuss the future directions in the depiction of LMCA disease.

Non-Dipper Blood Pressure Impact on Coronary Slow Flow in Hypertensive Patients With Normal Coronary Arteries.

Coronary slow flow (CSF) is linked to myocardial ischemia, malignant arrhythmias, and cardiovascular mortality. On the other hand, hypertension (HTN) is an important risk factor for vascular disorders. There is limited research on the relationship between CSF and HTN. This study aimed to investigate TIMI frame count (TFC), which is an indicator of CSF, in dipper and non-dipper hypertensive individuals with normal coronary arteries. The study was conducted as a retrospective observational study. Patients diagnosed with CSF and dipper or non-dipper hypertension were included in this study. Blood tests were routinely conducted for all patients. ECG was conducted for each patient, and echocardiography was performed. Coronary artery images were obtained in the CAG laboratory. Blood pressure (BP) measurements were obtained from the ambulatory Holter records. The patients were separated into two groups based on ambulatory Holter monitoring. The relationship between CSF and HTN was also examined. A total of 71 patients, comprising 25 women (37.2%) and46 men (62.8%) with an average age of 52.75±9.42 years, were enrolled in the research. Based on ambulatory BP, the individuals were separated into two groups: non-dipper (n=36) and dipper (n=35). The pulse rate was significantly higher in the non-dipper group (p<0.001). In terms of mean systolic and diastolic blood pressure, there were no substantial differences across the groups (p = 0.326 and p = 0.654, respectively). The daytime mean systolic and diastolic BP did not significantly differ across the groups (p = 0.842 and p = 0.421). The dipper group had substantially lower nighttime systolic and diastolic BP values (p <0.001). The LAD, Cx, and RCA TIMI frame scores were significantly lower in the dipper group (p<0.001). In this study, non-dipper patients had a greater CSF rate than dipper.

Automated analysis of fibrous cap in intravascular optical coherence tomography images of coronary arteries

Thin-cap fibroatheroma (TCFA) and plaque rupture have been recognized as the most frequent risk factor for thrombosis and acute coronary syndrome. Intravascular optical coherence tomography (IVOCT) can identify TCFA and assess cap thickness, which provides an opportunity to assess plaque vulnerability. We developed an automated method that can detect lipidous plaque and assess fibrous cap thickness in IVOCT images. This study analyzed a total of 4360 IVOCT image frames of 77 lesions among 41 patients. Expert cardiologists manually labeled lipidous plaque based on established criteria. To improve segmentation performance, preprocessing included lumen segmentation, pixel-shifting, and noise filtering on the raw polar (r, θ) IVOCT images. We used the DeepLab-v3 plus deep learning model to classify lipidous plaque pixels. After lipid detection, we automatically detected the outer border of the fibrous cap using a special dynamic programming algorithm and assessed the cap thickness. Our method provided excellent discriminability of lipid plaque with a sensitivity of 85.8% and A-line Dice coefficient of 0.837. By comparing lipid angle measurements between two analysts following editing of our automated software, we found good agreement by Bland–Altman analysis (difference 6.7° ± 17°; mean ~ 196°). Our method accurately detected the fibrous cap from the detected lipid plaque. Automated analysis required a significant modification for only 5.5% frames. Furthermore, our method showed a good agreement of fibrous cap thickness between two analysts with Bland–Altman analysis (4.2 ± 14.6 µm; mean ~ 175 µm), indicating little bias between users and good reproducibility of the measurement. We developed a fully automated method for fibrous cap quantification in IVOCT images, resulting in good agreement with determinations by analysts. The method has great potential to enable highly automated, repeatable, and comprehensive evaluations of TCFAs.

Performance analysis of various denoising filters on intravascular ultrasound coronary artery images

Accurate diagnosis of atherosclerotic coronary artery stenosis largely depends on intravascular ultrasound (IVUS) image quality. Coherent sources present during IVUS acquisition generates speckle noise and obstructs the clear view of the artery. Denoising aims to remove speckle noise while preserving edges and other important features. Accordingly, speckle noise suppression serves as an important preprocessing step for IVUS image analysis. This paper presents a performance analysis of various despeckling filters such as Median, Wiener, Speckle Reducing Anisotropic Diffusion (SRAD) filter, Wavelet, Non-local means (NLM) and curvelet based non-local means (CNLM) for IVUS images. To evaluate the efficacy, each filter is evaluated for three categories of cross-sectional IVUS images, that is, healthy, mild calcification, and dense calcification of real pullbacks from four patients. As it is challenging to denoise the IVUS images with complex lesions, that is, calcified arc >180°, in this performance analysis, the denoising performance for different denoising filters is considered not only for the healthy IVUS but also for complex lesions. Various measures such as peak signal-to-noise ratio (PSNR), structural similarity index (SSIM), feature similarity index (FSIM), and expert evaluation are used to compare these approaches. The results depict that the CNLM denoising filter outperforms others in terms of PSNR and FSIM for speckle noise suppression for IVUS images while preserving the essential edge and feature details for better image visualization and diagnosis.

Real-Time Detection and 3D Localization of Coronary Atherosclerosis Using a Microwave Imaging Technique: A Simulation Study.

Obtaining the exact position of accumulated calcium on the inner walls of coronary arteries is critical for successful angioplasty procedures. For the first time to our knowledge, in this work, we present a high accuracy imaging of the inner coronary artery using microwaves for precise calcium identification. Specifically, a cylindrical catheter radiating microwave signals is designed. The catheter has multiple dipole-like antennas placed around it to enable a 360° field-of-view around the catheter. In addition, to resolve image ambiguity, a metallic rod is inserted along the axis of the plastic catheter. The reconstructed images using data obtained from simulations show successful detection and 3D localization of the accumulated calcium on the inner walls of the coronary artery in the presence of blood flow. Considering the space and shape limitations, and the highly lossy biological tissue environment, the presented imaging approach is promising and offers a potential solution for accurate localization of coronary atherosclerosis during angioplasty or other related procedures.

Abstract 9610: Endothelial Function and Coronary Arterial Imaging in Youth-Onset Type 2 Diabetes: Evidence for Early Vascular Aging Compared to Age-Matched Peers

Introduction: Youth-onset type 2 diabetes (Y-T2D) may be associated with accelerated vascular aging, but the tempo and mechanisms are unknown. Non-invasive cardiac MRI coupled with ex-vivo experiments to assess endothelial function are ideal for assessing risk in young adults. Plasma exosomes are pro-inflammatory extra-cellular vesicles that may modulate endothelial dysfunction. Methods: We hypothesized that Y-T2D would have endothelial dysfunction compared to healthy age-matched peers measured by right coronary wall thickness (CWT) and coronary and brachial artery dilation during isometric handgrip exercise using a 3.0 Tesla cardiac MRI. In a subset of 4 Y-T2D, we isolated, characterized, and incubated plasma-derived exosomes in human coronary artery epithelial cells (HCAECs) compared to control cells. Results: Y-T2D (n=14, 40% female, age 19.4±1.3y, BMI 38±9kg/m 2 , mean±SD) compared to peers (n=16, 40% female, age 22.9±2.6 y, BMI 23±3 kg/m 2 ) had higher HbA1c (6.5 ± 1.2 vs 5.0 ± 0.5%), C-reactive protein (6.5±8.3 vs. 3.1±2.0 mg/L), systolic blood pressure (130±14 vs. 114±11 mmHg, all P &lt;0.05) but similar LDL-cholesterol and triglycerides. Y-T2D had greater CWT (1.34±0.13 vs. 1.22±0.13 mm, P =0.02) and impaired arterial dilation (Figure 1A). HCAECs incubated with Y-T2D exosomes induced phenotypic changes of endothelial dysfunction: reduced expression of phosphorylated endothelial nitric oxide synthase (peNOS), increased expression of endothelial membrane ICAM-1 and phosphorylation of pERK(1/2) (Figure 1B). Conclusion: Accelerated vascular aging in Y-T2D was associated with paradoxical exercise-induced coronary artery vasoconstriction and peripheral endothelial dysfunction despite young age and the absence of traditional risk factors such as severe hyperglycemia, frank hypertension, or dyslipidemia. Plasma exosomes should be explored in the pathogenesis of endothelial dysfunction and early vascular aging in Y-T2D.

Clinical utility of a new protocol of cardiac computed tomography in dogs.

The characteristics of non-electrocardiography- and electrocardiography-gated multidetector computed tomography have not been extensively studied in veterinary clinics but it can be useful for cardiac imaging. This study aimed to ascertain the differences between non-electrocardiography and electrocardiography gating methods and to establish their clinical utility based on patient history. Six client-owned dogs (two with patent ductus arteriosus, two with heart base tumour, one with pericardial mesothelioma, and one with normal health) were included in this study. All the dogs were examined using a non-electrocardiography-gated scan, followed by a retrospective electrocardiography-gated scan. Images were reviewed to determine the optimal scan timing and R-R interval in non-electrocardiography- and electrocardiography-gated images, respectively, for detailed coronary artery imaging, diagnostic quality of the best coronary artery visualisation in non-electrocardiography- and electrocardiography-gated images through visual assessment of the main coronary artery branches, and branching patterns of the left coronary artery. Further, we compared the size and margin demarcation of the heart or pericardial lesions in non-electrocardiography- and electrocardiography-gated images obtained from patients with heart or pericardial tumours. The optimal scan timing and R-R interval were the second-scan timing and end-diastole (70%-90%), respectively. Second-scan non-electrocardiography-gated images allowed coronary artery evaluation, indicating high-grade quality in visual assessment, except for the septal branch. Electrocardiography-gated images, but not non-ECG-gated images, clearly revealed pericardial nodules in two dogs. Our findings suggest the respective clinical utilities of non-electrocardiography- or electrocardiography-gated imaging using high-slice cardiac computed tomography based on patient history.

New frontiers in intracranial imaging with HF-OCT: Ex vivo human cerebrovasculature evaluation and in vivo intracranial arteries dynamic visualization

Optical coherence tomography (OCT) technology is a well-established diagnostic tool in multiple fields of medicine. Intravascular OCT has been used for more than a decade for the clinical imaging of coronary arteries, however, its use for the imaging of the human cerebrovasculature has been delayed by the challenges posed by the elevated vascular tortuosity. A novel high-frequency OCT (HF-OCT) probe designed for neurovascular use was evaluated in tortuous, ex vivo, human intracranial anatomy and, using an in vivo canine model, for the dynamic imaging of intracranial arteries and the subarachnoid trabecula (SAT). Using four cadavers, we investigated HF-OCT probe navigation and imaging performances in human anterior arterial circulation (from the M4 segment to internal carotid artery), in the posterior arterial circulation (from the P4 segment to vertebrobasilar junction) and in a broad range of venous sinuses. HF-OCT was able to gain distal access through elevated tortuosity and generate high-quality imaging data depicting vessel morphology, the vessel wall pathology (e.g., atherosclerotic disease and dissecting lesions), and the subarachnoid trabecula (SAT). Using an in vivo canine model, the HF-OCT probe was used to record stationary dynamic data in multiple intracranial vascular locations. Data showed the motion of the arteries and the SAT, including collisions between vessels, membranes, and the interaction between the SAT and the blood vessels. HF-OCT data allowed for the quantification of the dynamics of the vessels and the SAT, including vessel lateral motion with respect to the parenchyma, and collisions between large and small arteries. Results showed that the HF-OCT probe can overcome delivery obstacles in tortuous cerebrovascular anatomy and provide high-quality and high-resolution imaging at multiple distal locations, including M4 and P4 segments of the anterior and posterior circulations. HF-OCT has the potential to facilitate a better understanding of fine anatomical details of the cerebrovascular and perivascular environment, neurovascular disease, and collect real time information about the dynamics of the subarachnoid space and arteries and become a valuable diagnostic tool.

Concomitant cardiovascular malformations in isolated bicuspid aortic valve disease: a retrospective cross-sectional study and meta-analysis

BackgroundCongenital bicuspid aortic valve affects up to 2% of the general population. It occurs in complex congenital heart defects or in syndromes such as Turner, Marfan, or Loeys-Dietz. However, the majority of bicuspid aortic valves are considered to manifest as isolated malformations.MethodsWe aimed to assess retrospectively associated cardiovascular malformations in 200 individuals with bicuspid aortic valve considered to occur as an isolated manifestation. All individuals underwent transthoracic echocardiography, 164 thoracoabdominal tomographic imaging, and 84 coronary artery imaging. In addition, we also performed a meta-analysis of data from the literature to assess the occurrence of associate malformations.ResultsIn our retrospective cross-sectional study collective, the mean age was 45±15 years, 154 (77%) individuals were male. Anatomy of bicuspid aortic valve according to Schaefer was type 1 in 142 (71%), type 2 in 35 (18%), type 3 in 2 (1%), unicuspid in 6 (3%), and unclassified in 15 (8%) individuals. Coarctation of the aorta had 4.2% of individuals, 3.6% had coronary anomalies. No individual had a patent ductus arteriosus, 0.5% had atrial and ventricular septal defect each, 1.5% mitral valve prolapse. No individual had a tricuspid valve prolapse. Our meta-analysis identified in cohorts with isolated bicuspid aortic valve 11.8% (95% CI: 7.7–16.0%) individuals with aortic coarctation, 3.7% (95% CI: 1.2–6.1%) with coronary anomalies, 3.3% (95% CI: 0.0–6.7%) with patent ductus arteriosus, 5.9% (95% CI: 1.3–10.5%) with ventricular septal defect and 1.6% (95% CI: 1.1–2.1%) with mitral valve prolapse.ConclusionsIndividuals with isolated bicuspid aortic valve may exhibit a variety of associated cardiovascular malformations and therefore screening for associated malformations may be warranted.

Right and left coronary artery angiography with single Judkins left catheter via right radial artery

Objectives: The aim of this study was to assess the safety and efficacy of single Judkins left (JL) catheter to view right and left coronary artery in right transradial coronary angiography. Methods: A total of 266 patients underwent coronary angiography from the right radial artery were studied prospectively. Patients with ad-hoc percutaneous coronary intervention (PCI), peripheral angiography, ventriculography or aortography procedures (67 patients) were excluded from the study. Coronary angiography was performed with the JL catheter as single catheter group in 171 of the remaining 199 patients, and with the Judkins right and left catheters as the control group in the other 28 patients. Complications, procedure success, procedure time and fluoroscopy time were evaluated between the two groups. Results: Procedure success were 93% (159/171) in patients with a single catheter group and 96.4% (27/28) in patients with two catheter (Judkins right and left) group (control group) (p = 0.49). Complications (spasm) are the same between the two groups (8 of 171 [4.7%] patients in study group and 1 of 28 [3.6%] patients in control group, p = 0.79). Fluroscopy time in single JL catheter group was significantly higher (6.20 ± 4.97 min vs 3.76 ± 2.78 min, p = 0.01). Conclusions: Single JL catheter using to view right and left coronary artery in right transradial coronary angiography was safe and effective. In our study, the success rate of getting left and right coronary artery images with a single JL catheter as high as 93%. However, insisting on imaging with a single catheter extends the duration of fluoroscopy time.

Explainable deep learning algorithm for distinguishing incomplete Kawasaki disease by coronary artery lesions on echocardiographic imaging

Background and Objective: Incomplete Kawasaki disease (KD) has often been misdiagnosed due to a lack of the clinical manifestations of classic KD. However, it is associated with a markedly higher prevalence of coronary artery lesions. Identifying coronary artery lesions by echocardiography is important for the timely diagnosis of and favorable outcomes in KD. Moreover, similar to KD, coronavirus disease 2019, currently causing a worldwide pandemic, also manifests with fever; therefore, it is crucial at this moment that KD should be distinguished clearly among the febrile diseases in children. In this study, we aimed to validate a deep learning algorithm for classification of KD and other acute febrile diseases. Methods: We obtained coronary artery images by echocardiography of children (n = 138 for KD; n = 65 for pneumonia). We trained six deep learning networks (VGG19, Xception, ResNet50, ResNext50, SE-ResNet50, and SE-ResNext50) using the collected data. Results: SE-ResNext50 showed the best performance in terms of accuracy, specificity, and precision in the classification. SE-ResNext50 offered a precision of 81.12%, a sensitivity of 84.06%, and a specificity of 58.46%. Conclusions: The results of our study suggested that deep learning algorithms have similar performance to an experienced cardiologist in detecting coronary artery lesions to facilitate the diagnosis of KD.

Image quality and radiation doses of volumetric 320-row computed tomography angiography with prospective electrocardiogram-gating in the assessment of coronary arteries in neonates and infants.

Diagnostic imaging of coronary arteries is required in neonates and infants suspected of congenital or acquired coronary artery anomalies and in pre- and postoperative assessment of complex congenital heart diseases (CHD). Our study aimed to evaluate the image quality of volumetric 320-row computed tomography angiography (CTA) with prospective electrocardiogram (ECG)-gating for coronary arteries in neonates and infants with heart diseases, analyze factors influencing image quality and assess a radiation dose related to the procedure. The study included 110 CTA performed in neonates and infants with CHD. CTA was performed in 37 girls and 73 boys at a median (interquartile range [IQR]) age of 3.0 (0.5-5.0) months, median (IQR) body weight of 5 (3.66-6.5) kg, and median heart rate (HR) of 133 (92-150) beats per minute. The orifices of the left coronary artery were visible in 100% of CTA, the orifices of the right coronary arteries were visible in 96%, whereas all coronary segments were assessable in 45% of CTA. Patients with non-diagnostic segments were significantly younger, median (IQR) age of 2.0 (0.21-5.00) months, had lower body weight of 4.6 (3.45-6.07) kg and faster HR of 136.5 (120-150) beats per minute (P <0.05) than patients with diagnostic image quality in all segments (4.0, 2-6 months, 6.0, 4.2-7 kg, and 130; 110-150 beats per minute, respectively; P <0.05). CTA performed with volumetric 320-row prospective ECG-gating allows for good visibility of the coronary arteries with an acceptable radiation dose. Children aged >15 days, with body weight >4.85 kg and HR <130 beats per minute are good candidates for excellent quality non-invasive CTA of all segments of coronary arteries.

Fractional Flow Reserve (FFR) Estimation from OCT-Based CFD Simulations: Role of Side Branches.

The computational fluid dynamic method has been widely used to quantify the hemodynamic alterations in a diseased artery and investigate surgery outcomes. The artery model reconstructed based on optical coherence tomography (OCT) images generally does not include the side branches. However, the side branches may significantly affect the hemodynamic assessment in a clinical setting, i.e., the fractional flow reserve (FFR), defined as the ratio of mean distal coronary pressure to mean aortic pressure. In this work, the effect of the side branches on FFR estimation was inspected with both idealized and optical coherence tomography (OCT)-reconstructed coronary artery models. The electrical analogy of blood flow was further used to understand the impact of the side branches (diameter and location) on FFR estimation. Results have shown that the side branches decrease the total resistance of the vessel tree, resulting in a higher inlet flowrate. The side branches located at the downstream of the stenosis led to a lower FFR value, while the ones at the upstream had a minimal impact on the FFR estimation. Side branches with a diameter larger than one third of the main vessel diameter are suggested to be considered for a proper FFR estimation. The findings in this study could be extended to other coronary artery imaging modalities and facilitate treatment planning.

Importance of the heart rate in ultra-high-resolution coronary CT angiography with 0.35s gantry rotation time.

We investigated the effects of the heart rate (HR) on the motion artifact in coronary computed tomography angiography (CCTA) with ultra-high-resolution-CT (U-HRCT), and we clarified the upper limit of optimal HR in CCTA with U-HRCT in a comparison with conventional-resolution-CT (CRCT) on a cardiac phantom and in patients with CCTA. A pulsating cardiac phantom equipped with coronary models was scanned at static and HR simulations of 40-90 beats/min (bpm) at 10-bpm intervals using U-HRCT and CRCT, respectively. The sharpness and lumen diameter of the coronary model were quantitatively compared between U-HRCT and CRCT stratified by HR in the phantom study. We also assessed the visual inspections of clinical images in CCTA with U-HRCT. At the HRs ≤ 60bpm, the error of the lumen diameter of the U-HRCT tended to be smaller than that of the CRCT. However, at the HRs > 60bpm, the inverse was shown. For the image sharpness, the U-HRCT was significantly superior to the CRCT (p < 0.05). In the visual assessment, the scores were negatively correlated with HRs in patients (Spearman r = - 0.71, p < 0.01). A receiver-operating characteristic analysis revealed the HR of 61bpm as the optimal cutoff of the non-diagnostic image quality, with an area under the curve of 0.87, 95% sensitivity, and 71% specificity. At HRs ≤ 60bpm, U-HRCT was more accurate in the imaging of coronary arteries than CRCT. The upper limit of the optimal HR in CCTA with U-HRCT was approx. 60bpm.