Stress Imaging Research Articles

Self-reported Dermatological Manifestations, Perceived Stress, and Body Image of Young Adults During the Greek Lockdown Caused by the COVID-19 Outbreak

The aim of the study is to explore the perceived impact of social distancing measures due to COVID-19 on the manifestation of skin disorders and symptoms and their association with perceived stress and body image. For the purposes of this article, quantitative-driven mixed methods are used: the Greek versions of “Perceived Stress Scale” (Andreou et al., International Journal of Environmental Research and Public Health 8:3287–3298, 2011) to measure the stress levels among population, and “Multidimensional Body-Self Relations Questionnaire-Appearance Scales” (Argyrides and Kkeli, Psychological Reports 113:885–897, 2013) to examine body image satisfaction and assessment, along with open-ended questions are used. Questionnaires were distributed during the period of social distancing measures and 3 weeks following lockdown. Two hundred and fifty-three (N = 253) participants completed the survey: a control group of 164 participants without dermatological manifestations and a study group (N = 89) with dermatological manifestations.. Statistical analysis shows that adults with acne have a higher sense of self-efficacy in managing stressful situations than participants who have other skin disorders. Gender differences are observed as far as the perceived appearance is concerned. Thematic content analysis (Braun and Clarke, Qualitative Research in Psychology 3:77–101, 2006) shows that adults with skin symptoms associate their symptoms exacerbation with intrapersonal dimensions, such as stress and fear and environmental factors. The presence of skin disease is not necessarily associated with body satisfaction, body image, and cutaneous body image, although positively correlated with stress. The results are discussed and future recommendations are proposed.

Downstream testing after exercise ECG stress test – can we predict ischemia on subsequent vasodilator stress cardiac magnetic resonance?

Abstract Background Exercise ECG stress test (ExECG) is useful in the diagnostic work-up of patients with chest pain and known or suspected stable ischemic heart disease (SIHD). However, current guidelines recommend a stress imaging, ischemia-detecting technique such as vasodilator stress cardiac magnetic resonance (vs-CMR) if available. Whether clinical and ExECG variables can predict ischemia on subsequent vs-CMR testing is unknown. Material and methods We retrospectively included 289 patients who underwent an ExECG and a subsequent vs-CMR in the year after this test and who didn't undergo a revascularization procedure in this time frame. Clinical, ExECG and vs-CMR variables were included in the registry. vs-CMR was considered positive if ischemia was evident in at least one myocardial segment on stress first-pass perfusion without concomitant necrosis on late gadolinium enhancement imaging. We performed univariate and multivariate analysis to check for the association of variables with the risk of ischemia on vs-CMR. Results Mean time from ExECG to vs-CMR was 97,27±88,31 days and 91 vs-CMR were positive for ischemia. Age, male sex, diabetes mellitus, hypertension, dyslipidaemia and personal history of ischemic heart disease, percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) were predictors of ischemia on vs-CMR in the univariate analysis. On ExECG, time of exercise, exercise capacity, chest pain during ExECG, maximum heart rate (HR) and systolic blood pressure (SBP), % of predicted HR, chronotropic reserve index, maximum and reserve of double product and Duke Treadmill Score were also associated with ischemia on vs-CMR. However, the only independent predictors on multivariate binary logistic regression stepwise analysis were history of PCI (HR 3.79 [2.03–7.09], p<0.001) or CABG (HR 5.57 [1.80–17.26], p=0.003), maximum double product (HR 0.94 [0.90–0.99] per 1000 increase, p=0.02) and Duke Treadmill Score (HR 0.95 [0.91–0.99], p=0.019). Subgroup analysis showed that male sex (HR 1.95 [1.16–3.28], p=0.012), history of ischemic heart disease (HR 4.73 [2.88–7.76], p<0.001) and maximum double product (HR 0.94 [0.90–0.98] per 1000 increase, p=0.006) were predictors of ischemia on vs-CMR in non-revascularized patients (n=212). In revascularized patients (n=77) the only independent predictor was the Duke Treadmill Score on ExECG (HR 0.93 [0.86–0.99], p=0.048). Conclusions Several ExECG variables, namely Duke Treadmill Score and parameters of myocardial oxygen consumption such as maximum doble product, can predict the risk of ischemia on subsequent vs-CMR in revascularized and non-revascularized patients with chest pain. This can help select patients who should undergo vs-CMR afeter ExECG for ischemia detection. Funding Acknowledgement Type of funding sources: None.

Spatially resolved birefringence measurements with a digital micro-mirror device.

We demonstrate a novel technique to measure spatially resolved birefringence structures in an all-digital fashion with a digital micro-mirror device (DMD). The technique exploits the polarization independence of DMDs to apply holographic phase control to orthogonal polarization components and requires only a static linear polarizer as an analyzer for the resulting phase shift polarization measurements. We show the efficacy of this approach by spatially resolving complex polarization structures, including nano-structured metasurfaces, customized liquid crystal devices, as well as chiral L-Alanine and N-Acetyl-L-cystein crystals. Concentration dependent measurements of optical rotation in glucose and fructose solutions are also presented, demonstrating the technique's versatility. Unlike conventional approaches, our technique is calibration free and has no moving parts, offers high frame rates and wavelength independence, and is low cost, making it highly suitable to a range of applications, including pharmaceutical manufacturing, saccharimetry and stress imaging.

A comparative study on the stress image and adaptive parameter-modified methods for implementing free surface boundary conditions in elastic wave numerical modeling

The stress image method is a simple and effective approach for implementing the free surface boundary conditions in elastic wave numerical modeling. This method assumes that the normal and shear stresses perpendicular to the free surface are antisymmetric with respect to the free surface. In this way, the values of the normal and shear stresses above the free surface can be updated. However, the stress image method is based on an intuitive viewpoint and lacks a physical foundation. The adaptive parameter-modified method is a recently proposed approach for implementing the free surface boundary conditions. Through adaptive modifications of the density and elastic parameters at the free surface, the implementation of the free surface boundary conditions is achieved. Based on the adaptive parameter-modified method, a new interpretation of the stress image method is used. We determine that the stress image method is equivalent to the adaptive parameter-modified method in terms of the staggered-grid finite-difference scheme for the elastic wave equation in displacement form. This result provides a physical foundation and explanation of the stress image method. Therefore, we can further develop the stress image method from a physical viewpoint. Numerical examples are also developed to perform the theoretical analysis.

Irregular Autonomic Modulation Predicts Risky Drinking and Altered Ventromedial Prefrontal Cortex Response to Stress in Alcohol Use Disorder.

Autonomic dysfunction has been associated with risky drinking and alcohol use disorder (AUD). Although autonomic nervous system (ANS) activity has been attributed to the ventromedial prefrontal cortex (VmPFC)-limbic-striatal regions, the specific role of ANS disruption in AUD and its association with these regions remain unclear. Using functional magnetic resonance imaging (fMRI) and concurrent electrocardiogram (ECG), the current study examined neural correlates of ANS activity in AUD and its role in AUD pathology. Demographically matched 20 AUD patients and 20 social drinkers (SD) completed an fMRI task involving repeated exposure to stress, alcohol-cue and neutral-relaxing images in a block design. Based on the known VmPFC-limbic-striatal functions involved in emotions, reward and the ANS, we performed a regions of interest (ROI) analysis to examine the associations between ANS activity and neural responses in the VmPFC, amygdala, and ventral striatum. Across conditions, AUD patients showed significantly higher levels of overall heart rate (HR) and approximate entropy (ApEn) compared to SD (Ps < 0.05). In all participants, increased HR was associated with greater drinking volume (P < 0.05). In addition, higher ApEn levels were associated with greater drinking volume (P < 0.05) and decreased right VmPFC response to stress (P < 0.05). Our findings demonstrate ANS disruption in AUD indexed by high overall HR and ApEn. The association between ApEn and rVmPFC response suggests that ApEn may play a role in modulating drinking via interactions with neural regions of emotion regulation. These findings provide insight into patterns of ANS disruption and their relevance to AUD pathology.

Fluorescent tagging of endogenous Heme oxygenase-1 in human induced pluripotent stem cells for high content imaging of oxidative stress in various differentiated lineages

Tagging of endogenous stress response genes can provide valuable in vitro models for chemical safety assessment. Here, we present the generation and application of a fluorescent human induced pluripotent stem cell (hiPSC) reporter line for Heme oxygenase-1 (HMOX1), which is considered a sensitive and reliable biomarker for the oxidative stress response. CRISPR/Cas9 technology was used to insert an enhanced green fluorescent protein (eGFP) at the C-terminal end of the endogenous HMOX1 gene. Individual clones were selected and extensively characterized to confirm precise editing and retained stem cell properties. Bardoxolone-methyl (CDDO-Me) induced oxidative stress caused similarly increased expression of both the wild-type and eGFP-tagged HMOX1 at the mRNA and protein level. Fluorescently tagged hiPSC-derived proximal tubule-like, hepatocyte-like, cardiomyocyte-like and neuron-like progenies were treated with CDDO-Me (5.62–1000 nM) or diethyl maleate (5.62–1000 µM) for 24 h and 72 h. Multi-lineage oxidative stress responses were assessed through transcriptomics analysis, and HMOX1-eGFP reporter expression was carefully monitored using live-cell confocal imaging. We found that eGFP intensity increased in a dose-dependent manner with dynamics varying amongst lineages and stressors. Point of departure modelling further captured the specific lineage sensitivities towards oxidative stress. We anticipate that the newly developed HMOX1 hiPSC reporter will become a valuable tool in understanding and quantifying critical target organ cell-specific oxidative stress responses induced by (newly developed) chemical entities.

Stress Echo 2030: The Novel ABCDE-(FGLPR) Protocol to Define the Future of Imaging.

With stress echo (SE) 2020 study, a new standard of practice in stress imaging was developed and disseminated: the ABCDE protocol for functional testing within and beyond CAD. ABCDE protocol was the fruit of SE 2020, and is the seed of SE 2030, which is articulated in 12 projects: 1-SE in coronary artery disease (SECAD); 2-SE in diastolic heart failure (SEDIA); 3-SE in hypertrophic cardiomyopathy (SEHCA); 4-SE post-chest radiotherapy and chemotherapy (SERA); 5-Artificial intelligence SE evaluation (AI-SEE); 6-Environmental stress echocardiography and air pollution (ESTER); 7-SE in repaired Tetralogy of Fallot (SETOF); 8-SE in post-COVID-19 (SECOV); 9: Recovery by stress echo of conventionally unfit donor good hearts (RESURGE); 10-SE for mitral ischemic regurgitation (SEMIR); 11-SE in valvular heart disease (SEVA); 12-SE for coronary vasospasm (SESPASM). The study aims to recruit in the next 5 years (2021–2025) ≥10,000 patients followed for ≥5 years (up to 2030) from ≥20 quality-controlled laboratories from ≥10 countries. In this COVID-19 era of sustainable health care delivery, SE2030 will provide the evidence to finally recommend SE as the optimal and versatile imaging modality for functional testing anywhere, any time, and in any patient.

Need for syndesmotic fixation and assessment of reduction during ankle fracture fixation, with and without contralateral fluoroscopic images, has poor interobserver reliability.

To determine the interobserver reliability of syndesmosis assessment using intraoperative ankle mortise fluoroscopic images, with and without contralateral images. A survey of 19 operative ankle fracture cases was administered to 17 orthopedic surgeons. Respondents were presented with fluoroscopic mortise and stress images of the ankle after fracture fixation and asked if they would fix the syndesmosis. Final fluoroscopic mortise images were then shown, and respondents were asked to assess the reduction of the syndesmosis. Six weeks later, the survey was administered again with the addition of contralateral fluoroscopic ankle mortise images. Responses were compared to a standard response agreed upon by fellowship-trained orthopedic trauma surgeons. Interobserver reliability for syndesmosis fixation and reduction, with and without contralateral images, was considered weak (kappa 0.48 and 0.43; mean difference 0.05, 95% confidence interval (CI) 0.01 to 0.1) and minimal (kappa 0.25 and 0.22; mean difference 0.02, CI - 0.02 to 0.08). With the addition of contralateral mortise images, the number of surgeons who changed their response for syndesmosis fixation and reduction quality ranged from 0% to 41% and 0% to 88%; with the number of responses matching the standard increasing for both fixation (proportional difference (PD) 7%, CI 1% to 14%) and reduction (PD 14%, CI 7% to 21%); CONCLUSIONS: Interobserver reliability of syndesmosis fixation and reduction remained weak to minimal between surgeons, with and without contralateral images. Future studies are necessary to understand the variability in surgeon responses in order to improve the intraoperative assessment and fixation of syndesmotic injuries.

Relation between myocardial blood flow and cardiac events in diabetic patients with suspected coronary artery disease and normal myocardial perfusion imaging

BackgroundWe assessed the prognostic value of structural abnormalities and coronary vasodilator function in diabetic patients referred to a PET/CT for suspected coronary artery disease (CAD). MethodsWe studied 451 diabetics and 451 nondiabetics without overt CAD and normal myocardial perfusion. Myocardial blood flow (MBF) was computed from the dynamic rest and stress imaging. Myocardial flow reserve (MFR) was defined as ratio of hyperemic to baseline MBF and was considered reduced when < 2. ResultsDuring a mean follow-up of 44 months 33 events occurred. Annualized event rate (AER) was higher in diabetic than nondiabetic patients (1.4% vs 0.3%, P < .001). Diabetic patients with reduced MFR had higher AER compared to those with preserved MFR (3.3% vs 0.4%, P < .001). At Cox analysis, age, BMI and reduced MFR were independent predictors of events in diabetic patients. Patients with diabetes and reduced MFR had lower event-free survival compared to nondiabetic patients and MFR < 2 (P < .001). Event-free survival was similar in patients with diabetes and normal MFR and those without diabetes and reduced MFR. ConclusionsDiabetic patients with reduced MFR had higher AER and lower event-free survival compared to those with preserved MFR and to nondiabetic patients.

Measuring SPECT myocardial blood flow at the University of Ottawa Heart Institute

The introduction of new cardiac SPECT cameras has made it practical to do dynamic SPECT imaging and opened the door to performing myocardial blood flow (MBF) imaging with SPECT. In this paper, we describe in detail our approach to dynamic SPECT MBF imaging using a multi-pinhole cardiac SPECT camera and commercially available kinetic analysis software. We use a 1-day rest/stress protocol with 370 MBq injected at rest and 1,000 MBq at stress with a 1- to 2-hour interval between rest and stress imaging. The tracer is injected mechanically over 30 seconds using a syringe pump. Projection data are acquired in listmode for a duration of 11 minutes and then reframed into a dynamic series. Each image is reconstructed independently using vendor-supplied software. The dynamic images are corrected for residual activity and manually corrected for motion using rigid-body translation. The uptake rate constant, K1, is calculated using a 1-tissue-compartment kinetic model and converted to MBF using a previously determined extraction fraction correction.

Adherence to the European Society of Cardiology/European Society of Anaesthesiology recommendations on preoperative cardiac testing and association with positive results and cardiac events: a cohort study

BackgroundEuropean Society of Cardiology/European Society of Anaesthesiology (ESC/ESA) guidelines inform cardiac workup before noncardiac surgery based on an algorithm. Our primary hypotheses were that there would be associations between (i) the groups stratified according to the algorithms and major adverse cardiac events (MACE), and (ii) over- and underuse of cardiac testing and MACE. MethodsThis is a secondary analysis of a multicentre prospective cohort. Major adverse cardiac events were a composite of cardiac death, myocardial infarction, acute heart failure, and life-threatening arrhythmia at 30 days. For each cardiac test, pathological findings were defined a priori. We used multivariable logistic regression to measure associations. ResultsWe registered 359 MACE at 30 days amongst 6976 patients; classification in a higher-risk group using the ESC/ESA algorithm was associated with 30-day MACE; however, discrimination of the ESC/ESA algorithms for 30-day MACE was modest; area under the curve 0.64 (95% confidence interval: 0.61–0.67). After adjustment for sex, age, and ASA physical status, discrimination was 0.72 (0.70–0.75). Overuse or underuse of cardiac tests were not consistently associated with MACE. There was no independent association between test recommendation class and pathological findings (P=0.14 for stress imaging; P=0.35 for transthoracic echocardiography; P=0.52 for coronary angiography). ConclusionsDiscrimination for MACE using the ESC/ESA guidelines algorithms was limited. Overuse or underuse of cardiac tests was not consistently associated with cardiovascular events. The recommendation class of preoperative cardiac tests did not influence their yield. Clinical trial registrationNCT02573532.

Implications of transient ischaemic dilatation and impaired left ventricular ejection fraction reserve in patients with normal stress myocardial perfusion imaging and elevated coronary artery calcium

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Stress only (SO) instead of stress/rest single photon emission computed tomography myocardial perfusion imaging (MPI) is encouraged if perfusion and left ventricular ejection fraction (LVEF) are normal on SO images. Concurrent coronary artery calcium (CAC) scoring has also been recommended to assess atherosclerotic burden in ‘normal’ MPIs. However, the safety of SO MPI in high CAC cases is unclear as additional rest imaging may show transient ischaemic dilation (TID) and/or impaired LVEF reserve (iLVEFr) which are markers of severe coronary artery disease (CAD) and indicate ‘balanced ischaemia’. Purpose We aim to assess the incidence and outcomes of TID and iLVEFr in stress/rest MPIs with normal SO images and elevated CAC. Methods Retrospective analysis of all normal stress/rest MPIs performed between 1 March 2016 to 31 January 2017 with concurrently measured CAC &amp;gt;300. A SO protocol was not in place then. Prone post stress images were routinely done. Known CAD cases were excluded. A reader reviewed only the post stress supine/prone images and excluded cases ineligible for SO MPI (non-homogenous perfusion, LVEF ≤50%, abnormal wall motion). The remaining cases were assessed for TID (software derived TID ratio &amp;gt;1.20) and iLVEFr (stress LVEF – rest LVEF ≤-5%). Coronary angiography (CAG) and major adverse cardiac events (MACE, defined as cardiac death, non fatal myocardial infarction, revascularisation) within 24 months post MPI were traced using electronic medical records. Results There were 230 cases included (mean age 71, 56.5% male) of which 43 (18.7%) had TID and/or iLVEFr (9 TID, 22 iLVEFr, 12 both). There were no significant differences in baseline characteristics, CAC and aspirin/statin use between cases with or without TID and/or iLVEFr (Table 1). More patients in the TID and/or iLVEFr group underwent elective CAG [10 (23.3%) vs 10 (5.3%), p = 0.001] although CAG diagnosis of severe CAD (left main, 3-vessel or 2-vessel disease with proximal left anterior descending involvement) was not different [4/6 (40.0%) vs 5/10 (50.0%), p = 1.000). MACE was significantly higher in the TID and/or iLVEFr group [10 (23.3%) vs 16 (8.6%), p = 0.013], driven by higher elective revascularisation [8 (18.6%) vs 8 (4.3%), p = 0.003] with no significant differences in cardiac death or non fatal myocardial infarction (Table 2). Conclusion TID and/or iLVEFr is seen in &amp;lt;20% of cases eligible for SO MPI with high CAC, suggesting that routine rest scan in these cases exposes the majority to unnecessary radiation. Identification of TID and/or iLVEFr is associated with higher 24 month MACE, driven by higher elective revascularisation from more CAG referral. Approximately half of cases in each group had revascularisation for non severe CAD not typically associated with TID and/or impaired LVEFr. Overall cardiac death and non fatal myocardial infarction rates were low and not significantly different between groups with or without TID and/or iLVEFr.

DSPECT-specific normal limits for LV measurements: a new approach to derivation

Abstract Funding Acknowledgements Type of funding sources: None. Background Differences in spatial resolution and image filtering between the solid-state DSPECT and traditional Anger SPECT (A-SPECT) cameras are likely to result in differences in LV measurements. However, DSPECT- specific normal values have not been systematically derived. We used healthy organ-donor subjects from our high-volume solid organ transplant center for derivation of normal values. Purpose To report DSPECT-specific LV measurements normal limits derived from a unique cohort of donor subjects. Methods Subjects were 92 consecutive kidney or liver donors who underwent single day rest (5 mCi)- stress (15mCi) Tc-99m sestamibi gated SPECT myocardial perfusion imaging (MPI) on the DSPECT for pre-operative evaluation. Exclusion criteria included any cardiac disease or medications. LV measurements were made on the post-stress supine stress images using QGS®. Results Of 92 subjects (mean age 54.4 ± 15.0 and 39% men), mean EF for women and men were 77.2 ± 14.1% and 70.0 ± 14.7%, respectively. Mean end-diastolic volume for women and men were 67.0 ± 32.2 ml and 99.6 ± 51.6 ml (indexed 38.3 ± 17.2 ml/m2 and 48.1 ± 25.9 ml/m2), respectively. Mean LV wall volume for women and men were 95.9 ± 26.0 ml and 112.0 ± 48.8 ml (indexed 55.0 ± 13.8 ml/m2 and 54.1 ± 24.6 ml/m2), respectively. Conclusion We report DSPECT-specific LV measurements from normal subjects from which limits of normality can be derived for clinic use. Organ-donors who undergo pre-operative MPI are a suitable cohort for the derivation of normal values.

Self-compassion mediates the relationship between COVID-19-related stress and body image disturbance: Evidence from the United Kingdom under lockdown

The ongoing coronavirus (COVID-19) pandemic and attendant lockdown mandates may have detrimental effects on body image outcomes, which in turn highlights the importance of identifying protective factors. Here, we examined associations between COVID-19-related stress and body image disturbance, as well as the potential mediating and moderating role of self-compassion. During the third lockdown in the United Kingdom, we asked an online sample of adults (N = 600) to complete measures of COVID-19-related stress, body image disturbance, and self-compassion. Mediation analysis showed that higher COVID-19-related stress was significantly associated with greater body image disturbance, and that this relationship was mediated by self-compassion. In contrast, self-compassion did not significantly moderate the effects of stress on body image disturbance. These results suggest that promoting greater self-compassion may be a viable means of mitigating adverse outcomes from the COVID-19 pandemic on body image disturbance.

Neurobiology of loneliness: a systematic review.

Loneliness is associated with increased morbidity and mortality. Deeper understanding of neurobiological mechanisms underlying loneliness is needed to identify potential intervention targets. We did not find any systematic review of neurobiology of loneliness. Using MEDLINE and PsycINFO online databases, we conducted a search for peer-reviewed publications examining loneliness and neurobiology. We identified 41 studies (n = 16,771 participants) that had employed various methods including computer tomography (CT), structural magnetic resonance imaging (MRI), functional MRI (fMRI), electroencephalography (EEG), diffusion tensor imaging (DTI), single-photon emission computed tomography (SPECT), positron emission tomography (PET), and post-mortem brain tissue RNA analysis or pathological analysis. Our synthesis of the published findings shows abnormal structure (gray matter volume or white matter integrity) and/or activity (response to pleasant versus stressful images in social versus nonsocial contexts) in the prefrontal cortex (especially medial and dorsolateral), insula (particularly anterior), amygdala, hippocampus, and posterior superior temporal cortex. The findings related to ventral striatum and cerebellum were mixed. fMRI studies reported links between loneliness and differential activation of attentional networks, visual networks, and default mode network. Loneliness was also related to biological markers associated with Alzheimer’s disease (e.g., amyloid and tau burden). Although the published investigations have limitations, this review suggests relationships of loneliness with altered structure and function in specific brain regions and networks. We found a notable overlap in the regions involved in loneliness and compassion, the two personality traits that are inversely correlated in previous studies. We have offered recommendations for future research studies of neurobiology of loneliness.

Nanoscopic Imaging of Nucleolar Stress Enabled by Protein-Mimicking Carbon Dots.

The nucleolus is a central hub for coordinating cellular stress responses during cancer development and treatment. Accurate identification of nucleolar stress response is crucially desired for nucleolus-based diagnostics and therapeutics but technically challenging due to the need to address the ultrastructural analysis. Here, we report a protein-like CD with the integration of fluorescent blinking domains and RNA-binding motifs, which offers the ability to perform enhanced super-resolution imaging of the nucleolar ultrastructure. This image allows extraction of multidimensional information from the nucleolus for accurate distinguishment of different cells from the same cell types. Furthermore, we demonstrate for the first time this CD-depicted nucleolar ultrastructure as a sensitive hallmark to identify and discriminate subtle responses to various stressors as well as to afford RNA-related information that has been inaccessible by conventional immunofluorescence methods. This protein-mimicking CD could become a broadly useful probe for nucleolar stress studies in cell diagnostics and therapeutics.

Contemporary Role of Cardiac Magnetic Resonance in the Management of Patients with Suspected or Known Coronary Artery Disease.

Cardiac magnetic resonance imaging (CMR) is a useful non-invasive radiation-free imaging modality for the management of patients with coronary artery disease (CAD). CMR cine imaging provides the “gold standard” assessment of ventricular function, late gadolinium enhancement (LGE) provides useful data for the diagnosis and extent of myocardial scar and viability, while stress imaging is an established technique for the detection of myocardial perfusion defects indicating ischemia. Beyond its role in the diagnosis of CAD, CMR allows accurate risk stratification of patients with established CAD. This review aims to summarize the data regarding the role of CMR in the contemporary management of patients with suspected or known coronary artery disease.

Reverse redistribution-like change on dipyridamole-stress 99mTc-tetrofosmin imaging in a patient with angiographically mild coronary artery stenosis

A 50-year-old man with a 1-month history of chest pain presented to our hospital. Transthoracic echocardiography showed normal left ventricular wall motion. Coronary computed tomography angiography revealed a mild stenosis with low-density non-calcified plaque in the proximal left anterior descending coronary artery (LAD) (Figure 1A, yellow arrows); therefore, the patient underwent a 1-day protocol of dipyridamole stress and rest 99mTc-tetrofosmin myocardial perfusion imaging (MPI). Baseline electrocardiography was normal; however, he developed angina 8 minutes after the start of .56 mg·kg−1 (.14 mg·kg−1·min−1 for 4 minutes) of intravenous dipyridamole infusion and his electrocardiogram showed ST-segment elevation in the precordial leads (Figure 2). After intravenous aminophylline with sublingual nitroglycerin was given, the ST-segment elevation was gradually resolved. Stress MPI showed no perfusion defect (Figure 1B) with abnormal wall motion in the anterior and septal walls on gated MPI (Supplementary Material). He had recurrent angina after the stress MPI. Rest MPI at 2 hours after the stress test showed reverse redistribution-like reduced uptake in the LAD territory (Figure 1B) with normal left ventricular wall motion on gated MPI (Supplementary Material). As with the coronary computed tomography, invasive coronary angiography via the right radial artery demonstrated the mild stenosis in the proximal LAD (Figure 3, yellow arrow). Intravascular ultrasound and optical coherence tomography images showed coronary plaque with neovascularization (Figure 3, red arrows) and small thrombi (Figure 3, white arrows) at the minimum lumen area site, indicating the increased vulnerability of the coronary plaque.1 Percutaneous coronary intervention (PCI) with a drug-eluting stent (4.0 × 33 mm) was successfully performed (Figure 3, red arrows). On the day following the PCI, he underwent cardiopulmonary exercise testing and did not present with chest pain at peak exercise (VO2 at peak was 22.5 mL·kg−1·min−1 [6.4 METs]). Open in a separate window Figure 1 (A) Coronary computed tomography angiography revealed a mild stenosis (yellow arrows) with low-density non-calcified plaque in the proximal left anterior descending coronary artery (LAD). (B) Dipyridamole stress and rest 99mTc-tetrofosmin myocardial perfusion imaging (MPI). Stress MPI (300 MBq of 99mTc-tetrofosmin) showed no perfusion defect, whereas rest MPI (900 MBq of 99mTc-tetrofosmin) 2 hours after the stress test showed reduced uptake (reverse redistribution) in the LAD territory

Rayleigh waves propagation in an elastic medium with discrete subsurface fractures

Examining the propagation properties of Rayleigh waves in rocks is of notable theoretical and practical significance. In civil engineering and other fields, Rayleigh waves can be used to effectively predict various types of defects (such as fractures and cavities) in rocks. In this study, a numerical simulation method was performed to investigate the response characteristics of Rayleigh waves in rocks with randomly distributed fractures, and the effects of the density and spatial location of the fractures on the Rayleigh wavefields were examined. Specifically, the Rayleigh wave propagation was simulated using a high precision staggered-grid finite difference numerical method, and the stress boundary condition on the free surface of the medium was examined using an improved stress image method. In addition, the convolutional perfectly matched layer technique was used to achieve the absorbing boundary condition in the simulation interval. The numerical simulation results were noted to be in agreement with the analytical results. Under the long wavelength approximation, the effective media theory of fractures was considered, which could directly relate the elastic parameters to key properties such as the fracture density. Based on this concept, the numerical simulation results of the discrete fracture model and effective media theory model of the fractures were compared, and it was noted that the results of the two models exhibited a satisfactory agreement within the fracture density threshold of the effective media theory. Since the effective media theory model can effectively reflect the parameters such as the fracture density in rocks, the results of this study can provide theoretical guidance for the application of Rayleigh waves to predict fracture development in rocks.

Angiographic profiles in patients of persistent non-valvular atrial fibrillation from a tertiary care center in north india

Abstract Funding Acknowledgements Type of funding sources: None. Background The relationship of atrial fibrillation (AF) with coronary artery disease (CAD) is well established. Atrial ischemia due to obstructive CAD has been identified as one of the key risk factors, leading to AF. However, sufficient evidence exists as to the presence of myocardial ischemia on stress imaging, even without the presence of obstructive CAD in AF patients. Slow flow and coronary tortuosity on angiogram can lead to downstream myocardial ischemia independent of CAD. Purpose We aimed to delineate the angiographic profiles in AF patients with attention to slow flow and tortuosity leading to ischemia in those without obstructive CAD. Methods The study was a nonrandomised, prospective, single-centre observational study of consecutive patients of persistent non valvular AF. Symptomatic patients despite optimal medical therapy (OMT) for 3 months were recruited and all underwent coronary angiograms (CAG). Patients with known CAD or prior history of myocardial infarction were excluded. Further angiographic analysis was done in those without obstructive CAD to determine incidence of slow flow (&amp;gt;27 corrected TIMI frame count) and tortuosity (presence of ≥3 fixed bends in an epicardial artery). Results A total of 70 patients were recruited and followed for a mean duration of 12 ± 1.4 months. The mean age of the study group was 66.07 (±11.49). Hypertension (74%) was the commonest comorbidity followed by obesity (35%) and diabetes (30%). At CAG, 32/70 (45%) had obstructive CAD, 17/70 (24%) had non obstructive (&amp;lt;50-70% stenosis) CAD and 21/70 (30%) had normal coronaries without atherosclerosis. Amongst patients without obstructive CAD (n = 38) slow flow was seen in 16/38 (42%) and coronary tortuosity in 11/38 (29%) patients. There ware no differences in terms of death, HF and FVR hospitalisations or stroke at follow up between the obstructive CAD vs no obstructive CAD. However in patients without obstructive CAD, hospitalisations for FVR was significantly increased in those having slow flow on CAG, 9/12 (75%) vs 7/26 (27%) in those without slow flow (p value = 0.005). The mean TIMI frame count was also significantly higher in those with FVR hospitalisations 35.3 ± 11 vs 25.8 ± 8.9 (p value = 0.005). TIMI frame count &amp;gt;31 had a sensitivity of 83% and a specificity of 69% for predicting hospitalisations for FVR on ROC curve(AUC = 0.71). Conclusions CAD is closely related to AF and majority (70%) of our patients had evidence of atherosclerotic CAD on CAG in our study. A large proportion of patients with no evidence of obstructive CAD on CAG had slow flow or coronary tortuosity. Significantly increased hospitalisation for FVR seen in the slow flow group shows its significance and may lead to newer treatment modalities in future. Further larger studies looking at these aspects on CAG may give further insight as to the nature and prognosis of these entities.