Analysis of Epicardial Adipose Tissue Texture in Relation to Coronary Artery Calcification in PCCT: The EAT Signature!

(1) Background: Epicardial adipose tissue influences cardiac biology in physiological and pathological terms. As it is suspected to be linked to coronary artery calcification, identifying improved methods of diagnostics for these patients is important. The use of radiomics and the new Photon-Counting computed tomography (PCCT) may offer a feasible step toward improved diagnostics in these patients. (2) Methods: In this retrospective single-centre study epicardial adipose tissue was segmented manually on axial unenhanced images. Patients were divided into three groups, depending on the severity of coronary artery calcification. Features were extracted using pyradiomics. Mean and standard deviation were calculated with the Pearson correlation coefficient for feature correlation. Random Forest classification was applied for feature selection and ANOVA was performed for group comparison. (3) Results: A total of 53 patients (32 male, 21 female, mean age 57, range from 21 to 80 years) were enrolled in this study and scanned on the novel PCCT. "Original_glrlm_LongRunEmphasis", "original_glrlm_RunVariance", "original_glszm_HighGrayLevelZoneEmphasis", and "original_glszm_SizeZoneNonUniformity" were found to show significant differences between patients with coronary artery calcification (Agatston score 1-99/≥100) and those without. (4) Conclusions: Four texture features of epicardial adipose tissue are associated with coronary artery calcification and may reflect inflammatory reactions of epicardial adipose tissue, offering a potential imaging biomarker for atherosclerosis detection.

Pericoronary radiomics texture features associated with hypercholesterolemia on a photon-counting-CT.

Introduction: Pericoronary adipose tissue (PCAT) stands in complex bidirectional interaction with the surrounding arteries and is known to be connected to many cardiovascular diseases involving vascular inflammation. PCAT texture may be influenced by other cardiovascular risk factors such as hypercholesterolemia. The recently established photon-counting CT could improve texture analysis and help detect those changes by offering higher spatial resolution and signal-to-noise ratio. Methods: In this retrospective, single-center, IRB-approved study, PCAT of the left and right coronary artery was manually segmented and radiomic features were extracted using pyradiomics. The study population consisted of a test collective and a validation collective. The collectives were each divided into two groups defined by the presence or absence of hypercholesterolemia, taken from self-reported conditions and confirmed by medical records. Mean and standard deviation were calculated with Pearson correlation coefficient for correlation of features and visualized as boxplots and heatmaps using R statistics. Random forest feature selection was performed to identify differentiating features between the two groups. 66 patients were enrolled in this study (34 female, mean age 58 years). Results: Two radiomics features allowing differentiation between PCAT texture of the groups were identified (p-values between 0.013 and 0.24) and validated. Patients with hypercholesterolemia presented with a greater concentration of high-density values as indicated through analysis of specific texture features as "gldm_HighGrayLevelEmphasis" (23.95 vs. 22.99) and "glrlm_HighGrayLevelRunEmphasis" (24.21 vs. 23.31). Discussion: Texture analysis of PCAT allowed differentiation between patients with and without hypercholesterolemia offering a potential imaging biomarker for this specific cardiovascular risk factor.

Description of a new clinical syndrome: thoracic constriction without evidence of the typical funnel-shaped depression-the "invisible" pectus excavatum.

Pectus excavatum (PE) is a congenital malformation with a funnel-shaped depression of the sternum that can lead to cardiac symptoms. However, there are patients with thoracic constriction (defined as elevated Haller-Index > 3.25 determined by cardiac magnetic resonance imaging (CMR)) without visible evidence of PE, leading to similar complaints. Between January 2004 till June 2020, patients who underwent CMR for further evaluation of the heart, due to cardiac symptoms were enrolled and compared to controls. Biventricular global strain analysis was assessed using feature tracking (CMR-FT). ECG and/or Holter recordings were performed to detect rhythm events. Cardiac symptoms were evaluated in detail using a questionnaire. Finally, 88 patients (male 35, female 53) with elevated Haller-Index (3.9 ± 0.8) were included and compared to CMR data from 25 individuals with confirmed PE and 25 healthy controls (HC). Mean age at time of CMR was 35 ± 16 years. The most common symptoms at presentation were palpitations (41%), followed by dyspnea (24%) and atypical chest pain (14%). Three patients (3%) had atrial fibrillation or atrial flutter. Concomitant phenomena were pericardial effusion in 39% and mitral valve prolapse (MVP) in 27% of the study cohort. While there were no differences in left ventricular function or volumes, right ventricular function (RVEF) was significantly lower in patients with internal PE compared to HC (RVEF (%) 50 ± 5 vs 59 ± 4, p < 0.01). Strain analysis revealed only discrete changes in RV strain, implying a purely mechanical problem in the absence of structural changes. RV dimensions were negatively correlated with the size of thoracic indices (r = 0.41), reflecting the extent of thoracic constriction. MVP was more prevalent in patients with greater thoracic indices (r = 0.24). The described cohort, referred to as internal PE because of the absence of external changes, showed similar CMR morphologic findings as patients with real PE (especially altered dimensions of the right heart and a lower RVEF). In addition, there was a high incidence of rhythm disturbances, such as extrasystoles or arrhythmias. In one-third of the study cohort additional abnormalities such as pericardial effusion or MVP were present, with MVP being found more frequently in patients with larger thoracic indices, suggesting a possible common pathogenesis.Trial registration: ISRCTN registry, ISRCTN15355937, retrospectively registered 03.06.2022, https://www.isrctn.com/ISRCTN15355937?q=15355937&filters=&sort=&offset=1&totalResults=1&page=1&pageSize=10 .

Radiomics in Cardiac Computed Tomography.

In recent years, there has been an increasing recognition of coronary computed tomographic angiography (CCTA) and gated non-contrast cardiac CT in the workup of coronary artery disease in patients with low and intermediate pretest probability, through the readjustment guidelines by medical societies. However, in routine clinical practice, these CT data sets are usually evaluated dominantly regarding relevant coronary artery stenosis and calcification. The implementation of radiomics analysis, which provides visually elusive quantitative information from digital images, has the potential to open a new era for cardiac CT that goes far beyond mere stenosis or calcification grade estimation. This review offers an overview of the results obtained from radiomics analyses in cardiac CT, including the evaluation of coronary plaques, pericoronary adipose tissue, and the myocardium itself. It also highlights the advantages and disadvantages of use in routine clinical practice.

Sparse 3D contrast-enhanced whole-heart imaging for coronary artery evaluation.

BACKGROUND: We investigated the feasibility of evaluating coronary arteries with a contrast-enhanced (CE) self-navigated sparse isotropic 3D whole heart T1-weighted magnetic resonance imaging (MRI) study sequence. METHODS: A total of 22 consecutive patients underwent coronary angiography and/or cardiac computed tomography (CT) including cardiac MRI. The image quality was evaluated on a 3-point Likert scale. Inter-reader variability for image quality was analyzed with Cohen's kappa for the main coronary segments (left circumflex [LCX], left anterior descending [LAD], right coronary artery [RCA]) and the left main trunk (LMT). RESULTS: Inter-reader agreement for image quality of the coronary tree ranged from substantial to perfect, with a Cohen's kappa of 0.722 (RCAmid) to 1 (LCXprox). The LMT had the best image quality. Image quality of the proximal vessel segments differed significantly from the mid- and distal segments (RCAprox vs. RCAdist, p < 0.05). The LCX segments showed no significant difference in image quality along the vessel length (LCXprox vs. LCXdist, p = n.s.). The mean acquisition time for the study sequence was 553 s (±46 s). CONCLUSION: Coronary imaging with a sparse 3D whole-heart sequence is feasible in a reasonable amount of time producing good-quality imaging. Image quality was poorer in distal coronary segments and along the entire course of the LCX.

Septal myocardial scar burden predicts the response to cardiac contractility modulation in patients with heart failure.

We hypothesized that myocardial septal scarring, assessed by cardiac magnetic resonance (CMR) using late gadolinium enhancement (LGE), at the site of cardiac contractility modulation (CCM) lead placement may predict treatment response. Eligible heart failure (HF) patients underwent LGE CMR imaging before CCM device implantation. The response to CCM therapy at follow-up was determined by a change in NYHA class and echocardiographic left ventricular ejection fraction (LVEF) assessment. Patients were classified as responders, if they showed an improvement in either NYHA class or improvement of LVEF by ≥ 5%. 58 patients were included. 67% of patients were classified as responders according to improved NYHA; 55% according to LVEF improvement. 74% of patients were responders if either NYHA class or LVEF improvement was observed. 90% of responders (according to NYHA class) showed septal LGE < 25% at septal position of the leads, while 44% of non-responders showed septal LGE > 25% (p < 0.01). In patients treated with CCM, an improvement of NYHA class was observed when leads were placed at myocardial segments with a CMR- LGE burden less than 25%.

High Temporal Resolution Dual-Source Photon-Counting CT for Coronary Artery Disease: Initial Multicenter Clinical Experience.

The aim of this paper is to evaluate the diagnostic image quality of spectral dual-source photon-counting detector coronary computed tomography angiography (PCD-CCTA) for coronary artery disease in a multicenter study. The image quality (IQ), assessability, contrast-to-noise ratio (CNR), Agatston score, and radiation exposure were measured. Stenoses were quantified and compared with invasive coronary angiography, if available. A total of 92 subjects (65% male, age 58 ± 14 years) were analyzed. The prevalence of significant coronary artery disease (CAD) (stenosis ≥ 50%) was 17% of all patients, the range of the Agatston score was 0−2965 (interquartile range (IQR) 0−135). The IQ was very good (one, IQR one−two), the CNR was very high (20 ± 10), and 5% of the segments were rated non-diagnostic. The IQ and assessability were higher in proximal coronary segments (p < 0.001). Agatston scores up to 600 did not significantly affect the assessability of the coronary segments (p = 0.3). Heart rate influenced assessability only at a high-pitch mode (p = 0.009). For the invasive coronary angiography (ICA) subgroup (n = nine), the diagnostic performance for CAD per segment was high (sensitivity 92%, specificity 96%), although the limited number of patients who underwent both diagnostic modalities limits the generalization of this finding at this stage. PCD-CCTA provides good image quality for low and moderate levels of coronary calcifications.

Case Report: Transient Increase of CMR T1 Mapping Indices in a Patient With COVID-19 mRNA Vaccine Induced Acute Myocarditis.

Background: Acute myocarditis is commonly associated with viral infections, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Myocarditis following mRNA COVID-19 vaccination has also been reported, however this is rare and usually resolves within days or weeks. We present a case of acute myocarditis reported after vaccination with mRNA-1273 COVID-19 vaccine (Moderna) diagnosed using cardiac magnetic resonance imaging (CMR). This report describes the utility of CMR in the diagnosis and follow-up of such patients using parameters which could suggest the clinical course of myocarditis. Case Summary: A 23-year-old male presented in the emergency department with complaints of chest pain radiating to the left arm following vaccination with the second dose of COVID-19 mRNA-1273 vaccine (Moderna). Patient's history revealed an incidence of myocarditis in the past. CMR showed a mid-range left ventricular ejection fraction (38%) and subepicardial late gadolinium enhancement (LGE) in the inferolateral and apical myocardial segments with diffuse elevation of native T1 mapping relaxation times in all myocardial segments. The patient was admitted briefly in the intensive care unit and after a favorable clinical course was discharged from the hospital in stable condition. A follow-up CMR after 3 months revealed normalization of LVEF (57%) and native T1- times in most segments. Scarred myocardium reflecting chronic myocarditis continued to show elevated T1 times. Conclusions: Our patient presenting with acute myocarditis after recent COVID-19 mRNA vaccination reported a favorable clinical course. CMR revealed increased T1 mapping relaxation times diffusely spread across the myocardium and an impairment of the left ventricular function (LVEF) during the acute phase. However, the LVEF as well as the T1 times normalized at follow-up in all segments except for myocardium affected by chronic myocarditis.

Prediction of cardiac events with non-contrast magnetic resonance feature tracking in patients with ischaemic cardiomyopathy.

AIMS: The aim of this study was to evaluate the prognostic value of feature tracking (FT) derived cardiac magnetic resonance (CMR) strain parameters of the left ventricle (LV)/right ventricle (RV) in ischaemic cardiomyopathy (ICM) patients treated with an implantable cardioverter-defibrillator (ICD). Current guidelines suggest a LV-ejection fraction ≤35% as major criterion for ICD implantation in ICM, but this is a poor predictor for arrhythmic events. Supplementary parameters are missing. METHODS AND RESULTS: Ischaemic cardiomyopathy patients (n = 242), who underwent CMR imaging prior to primary and secondary implantation of ICD, were classified depending on EF ≤ 35% (n = 188) or >35% (n = 54). FT parameters were derived from steady-state free precession cine views using dedicated software. The primary endpoint was a composite of cardiovascular mortality (CVM) and/or appropriate ICD therapy. There were no significant differences in FT-function or LV-/RV-function parameters in patients with an EF ≤ 35% correlating to the primary endpoint. In patients with EF > 35%, standard CMR functional parameters, such as LV-EF, did not reveal significant differences. However, significant differences in most FT parameters correlating to the primary endpoint were observed in this subgroup. LV-GLS (left ventricular-global longitudinal strain) and RV-GRS (right ventricular-global radial strain) revealed the best diagnostic performance in ROC curve analysis. The combination of LV-GLS and RV-GRS showed a sensitivity of 85% and a specificity of 76% for the prediction of future events. CONCLUSIONS: The impact of FT derived measurements in the risk stratification of patients with ICM depends on LV function. The combination of LV-GLS/RV-GRS seems to be a predictor of cardiovascular mortality and/or appropriate ICD therapy in patients with EF > 35%.

Risk stratification of patients with Brugada syndrome: the impact of myocardial strain analysis using cardiac magnetic resonance feature tracking.

OBJECTIVE: This study evaluated the prognostic significance of cardiac magnetic resonance myocardial feature tracking (CMR-FT) in patients with Brugada syndrome (BrS) to detect subclinical alterations and predict major adverse events (MAE). METHODS: CMR was performed in 106 patients with BrS and 25 healthy controls. Biventricular global strain analysis was assessed using CMR-FT. Patients were followed over a median of 11.6 [8.8 ± 13.8] years. RESULTS: The study cohort was subdivided according to the presence of a spontaneous type 1 ECG (sECG) into sBrS (BrS with sECG, n = 34 (32.1%)) and diBrS (BrS with drug-induced type 1 ECG, n = 72 (67.9%)). CMR-FT revealed morphological differences between sBrS and diBrS patients with regard to right ventricular (RV) strain (circumferential (%) (sBrS -7.9 ± 2.9 vs diBrS - 9.5 ± 3.1, p = 0.02) and radial (%) (sBrS 12.0 ± 4.3 vs diBrS 15.4 ± 5.4, p = 0.004)). During follow-up, MAE occurred in 11 patients (10.4%). Multivariable analysis was performed to identify independent predictors for the occurrence of events during follow-up. The strongest predictive value was found for RV circumferential strain (OR 3.2 (95% CI 1.4 - 6.9), p = 0.02) and RVOT/BSA (OR 3.1 (95% CI 1.0 - 7.0), p = 0.03). CONCLUSIONS: Myocardial strain analysis detected early subclinical alterations, prior to apparent changes in myocardial function, in patients with BrS. While usual functional parameters were within the normal range, CMR-FT revealed pathological results in patients with an sECG. Moreover, RV circumferential strain and RVOT size provided additional prognostic information on the occurrence of MAE during follow-up, which reflects electrical vulnerability.

Determinants of arterial stiffness in patients with atrial fibrillation.

BACKGROUND: Arterial stiffness has emerged as a strong predictor of cardiovascular disease, end-organ damage and all-cause mortality. Although increased arterial stiffness has been described as a predictor of atrial fibrillation, the relationship between arterial stiffness and atrial fibrillation is uncertain. AIM: We assessed arterial stiffness in patients with atrial fibrillation compared with that in a control group. METHODS: We enrolled 151 patients with atrial fibrillation who underwent pulmonary vein isolation (mean age 71.1±9.8 years) and 54 control patients with similar cardiovascular risk profiles and sinus rhythm, matched for age (mean age 68.6±15.7 years) and sex. Aortic distensibility as a measure of arterial stiffness was assessed by transoesophageal echocardiography. Patients with atrial fibrillation were followed over a median of 21 (15 to 31) months. RESULTS: Compared with control patients, patients with atrial fibrillation had significantly lower aortic distensibility (1.8±1.1 vs. 2.1±1.1 10-3mmHg-1; P=0.02). Age (hazard ratio 0.67, 95% confidence interval 0.003 to 0.03; P=0.02) and pulse pressure (hazard ratio -1.35, 95% confidence interval -0.07 to -0.03; P<0.0001) were the strongest predictors of decreased aortic distensibility in the study cohort. This effect was independent of the type of atrial fibrillation (paroxysmal/persistent). During follow-up, decreased aortic distensibility was a predictor of cardiovascular and all-cause hospitalizations, as well as recurrences of atrial fibrillation, with a higher incidence rate of events in patients in the lowest aortic distensibility quartile (P=0.001). CONCLUSIONS: Aortic distensibility was significantly reduced in patients with atrial fibrillation, with age and pulse pressure showing the strongest correlation, independent of the type of atrial fibrillation. Additionally, decreased aortic distensibility was associated with cardiovascular and all-cause hospitalizations, as well as recurrences of atrial fibrillation, which showed a quartile-dependent occurrence.

Extent of peri-infarct scar on late gadolinium enhancement cardiac magnetic resonance imaging and outcome in patients with ischemic cardiomyopathy.

BACKGROUND: Only a minority of patients who receive an implantable cardioverter-defibrillator (ICD) on the basis of left ventricular ejection fraction receive appropriate ICD therapy. Peri-infarct scar zone assessed by late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) is a possible substrate for ventricular tachyarrhytmias (VTAs). OBJECTIVE: The aim of our prospective study was to determine whether LGE-CMR parameters can predict the occurrence of VTA in patients with ischemic cardiomyopathy (ICM). METHODS: Two hundred sixteen patients with ICM underwent CMR imaging before primary or secondary ICD implantation and were prospectively followed. We assessed CMR indices and CMR scar characteristics (infarct core and peri-infarct zone) to predict outcome and VTAs. RESULTS: Patients were followed up for 1497 days (interquartile range 697-2237 days). Forty-seven patients (21%) received appropriate therapy during follow-up. Patients with appropriate ICD therapy had smaller core scar (31.5% ± 8.5% vs 36.8% ± 8.9%; P = .0004) but larger peri-infarct scar (12.4% ± 2.6% vs 10.5% ± 2.9%; P = .0001) than did patients without appropriate therapy. In multivariate Cox regression analysis, peri-infarct scar (hazard ratio 1.15; 95% confidence interval 1.07-1.24; P = .0001) was independently and significantly associated with VTAs whereas left ventricular ejection fraction, right ventricular ejection fraction, core scar, and left atrial ejection fraction were not. CONCLUSION: Scar extent of peri-infarct border zone was significantly associated with appropriate ICD therapy. Thus, LGE-CMR parameters can identify a subgroup of patients with ICM and an increased risk of life-threatening VTAs.

Arterial Stiffness Is Associated With Increased Symptom Burden in Patients With Atrial Fibrillation.

BACKGROUND: Increased arterial stiffness (AS) has been described as a predictor of atrial fibrillation (AF). This study was performed to assess whether increased AS leads to a higher symptom burden in patients with AF. METHODS: One hundred sixty-two consecutive patients (104 male, 58 female) with diagnosed AF (paroxysmal or persistent) were enrolled. Symptoms most likely attributable to AF were quantified according to the Canadian Cardiovascular Society Severity of Atrial Fibrillation (SAF) scale. AS indices (aortic distensibility, cyclic circumferential strain, and aortic compliance) were characterized using transoesophageal echocardiography. RESULTS: The cohort was divided into asymptomatic to oligosymptomatic (SAF scale 0-1, n = 78 [48.1%]) and symptomatic (SAF scale ≥ 2, n = 84 [51.9%]) patients. Symptomatic patients tended to be younger (median, 75 [interquartile range (IQR) 67-80] vs 71 [65-79]; P = 0.047) and were more likely to be female (22 [28.2%] vs 36 [42.9%]; P = 0.052). Hypertension was more frequent in symptomatic patients. Aortic compliance indices each were reduced in symptomatic patients, most pronounced for aortic compliance (median, 0.05 [IQR 0.03-0.06] vs 0.04 [0.03-0.05] cm/mm Hg; P = 0.01) followed by cyclic circumferential strain (median, 0.09 [IQR 0.07-0.11] vs 0.07 [0.04-0.10]; P = 0.02) and aortic distensibility (10-3 mm Hg-1, median, 1.74 [IQR 1.34-2.24] vs 1.54 [1.12-2.08]; P = 0.03). Multivariable analysis revealed aortic compliance as an independent predictor for symptoms in patients with AF with an odds ratio of 2.6 (95% confidence interval, 1.2-3.4; P = 0.003). CONCLUSIONS: AS contributes to a high symptom burden in patients with AF, emphasizing the prognostic role of AS in the early detection and prevention in patients with AF.

Extent of Late Gadolinium Enhancement Predicts Thromboembolic Events in Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: Thromboembolic complications such as ischemic stroke or peripheral arterial thromboembolism are known complications in hypertrophic cardiomyopathy (HCM). We sought to assess the clinical and cardiovascular magnetic resonance (CMR) characteristics of patients with HCM suffering from thromboembolic events and analyzed the predictors of these unfavorable outcomes.Methods and Results:The 115 HCM patients underwent late gadolinium enhanced (LGE) CMR and were included in the study. Follow-up was 5.6±3.6 years. The primary endpoint was the occurrence of thromboembolic events (ischemic stroke or peripheral arterial thromboembolism). It occurred in 17 (14.8%) patients (event group, EG), of whom 64.7% (11) were men. During follow-up, 10 (8.7%) patients died. Patients in the EG showed more comorbidities, such as heart failure (EG 41.2% vs. NEG (non-event group) 14.3%, P<0.01) and atrial fibrillation (AF: EG 70.6% vs. NEG 36.7%, P<0.01). Left atrial end-diastolic volume was significantly higher in the EG (EG 73±24 vs. NEG 50±33 mL/m2, P<0.01). Both the presence and extent of LGE were enhanced in the EG (extent% EG 23±15% vs. NEG 8±9%, P<0.0001). No patient without LGE experienced a thromboembolic event. Multivariate analysis revealed AF and LGE extent as independent predictors. CONCLUSIONS: LGE extent (>14.4%) is an independent predictor for thromboembolic complications in patients with HCM and might therefore be considered as an important risk marker. The risk for thromboembolic events is significantly elevated if accompanied by AF.

Recurrence of Atrial Fibrillation in Dependence of Left Atrial Volume Index.

BACKGROUND/AIM: Despite advances in the treatment strategies of patients with atrial fibrillation (AF), the risk of AF recurrences is still over 50%. An increased left atrial volume index (LAVI) reflects left ventricular diastolic dysfunction (DD) and deterioration of the LA function. This study aims to determine AF recurrence following cardioversion (CV) or catheter ablation for AF (pulmonary vein isolation; PVI) in dependence of DD and LAVI. PATIENTS AND METHODS: One hundred and sixty-two patients with paroxysmal or persistent AF in whom either CV or PVI were performed were included and followed over a mean of 22.9±3.8 months. Recurrence was defined as any recurrence of AF that occurred 3 months following the procedure. DD and LAVI were assessed using transthoracic echocardiography (TTE). RESULTS: Recurrent AF occurred in 100 (61.7%) patients, predominantly following CV [CV 41 (76.2%) vs. PVI 59 (54.6%), p<0.0001]. Both DD and an increased LAVI were more common in the recurrence-group [DD 46.0% vs. 14.5%, p=0.0001; LAVI (ml/m2) 49.0±18.6 vs. 26.3±7.0, p<0.0001]. ROC analysis revealed LAVI>36 ml/m2 as cut-off (p<0.0001, AUC=0.92, 95%CI=0.87-0.97, sensitivity=76%, specificity=94%). In the multivariate analysis, DD (HR=1.6, 95%CI=1.3-2.1, p=0.04) and LA enlargement (defined as LAVI>36 ml/m2 with HR=2.1, 95%CI=1.8-2.7, p<0.0001) could be identified as independent predictors of AF recurrence after attempting to control the heart rhythm. CONCLUSION: LA enlargement and DD are independent risk factors associated with AF recurrence after initial successful rhythm control attempt. These findings have implications for timing of either ablation or CV.

Correlation of machine learning computed tomography-based fractional flow reserve with instantaneous wave free ratio to detect hemodynamically significant coronary stenosis.

BACKGROUND: Fractional flow reserve based on coronary CT angiography (CT-FFR) is gaining importance for non-invasive hemodynamic assessment of coronary artery disease (CAD). We evaluated the on-site CT-FFR with a machine learning algorithm (CT-FFRML) for the detection of hemodynamically significant coronary artery stenosis in comparison to the invasive reference standard of instantaneous wave free ratio (iFR®). METHODS: This study evaluated patients with CAD who had a clinically indicated coronary computed tomography angiography (cCTA) and underwent invasive coronary angiography (ICA) with iFR®-measurements. Standard cCTA studies were acquired with third-generation dual-source computed tomography and analyzed with on-site prototype CT-FFRML software. RESULTS: We enrolled 40 patients (73% males, mean age 67 ± 12 years) who had iFR®-measurement and CT-FFRML calculation. The mean calculation time of CT-FFRML values was 11 ± 2 min. The CT-FFRML algorithm showed, on per-patient and per-lesion level, respectively, a sensitivity of 92% (95% CI 64-99%) and 87% (95% CI 59-98%), a specificity of 96% (95% CI 81-99%) and 95% (95% CI 84-99%), a positive predictive value of 92% (95% CI 64-99%), and 87% (95% CI 59-98%), and a negative predictive value of 96% (95% CI 81-99%) and 95% (95% CI 84-99%). The area under the receiver operating characteristic curve for CT-FFRML on per-lesion level was 0.97 (95% CI 0.91-1.00). Per lesion, the Pearson's correlation between the CT-FFRML and iFR® showed a strong correlation of r = 0.82 (p < 0.0001; 95% CI 0.715-0.920). CONCLUSION: On-site CT-FFRML correlated well with the invasive reference standard of iFR® and allowed for the non-invasive detection of hemodynamically significant coronary stenosis.

Non-invasive measurement of hemodynamic response to postural stress using inert gas rebreathing.

In postural stress, an increased preload volume leads to higher stroke volume (SV) according to the Frank-Starling law of the heart. The present study aimed to evaluate the hemodynamic response to postural stress using non-invasive inert gas rebreathing (IGR) in patients with normal as well as impaired left ventricular function. Hemodynamic measurements were performed in 91 patients undergoing cardiac magnetic resonance imaging (CMR). Mean cardiac output and SV determined by IGR were 4.4±1.3 l/min and 60±19 ml in the upright position, which increased significantly to 5.0±1.2 l/min and 75±23 ml in the supine position (P<0.01). Left ventricular systolic function was normal [ejection fraction (EF) ≥55%] in 42 patients as determined by CMR. In 21 patients, EF was mildly abnormal (45-54%), in 16 patients moderately abnormal (30-44%) and in 12 patients severely abnormal (<30%). An overall trend for a lower percentage change in SV (%ΔSV) was indicated with increasing impairment of ejection fraction. In patients with abnormal EF in comparison to those with normal EF, the %ΔSV was significantly lower (13% vs. 22%; P=0.03). Non-invasive measurement of cardiac function using IGR during postural changes may be feasible and detected significant difference in %ΔSV in patients with normal and impaired EF according to the Frank-Starling law of the heart. Several clinical scenarios including cases of heart rhythm disturbances or pulmonary or congenital heart disease are worthy of further investigation.

Saturation-Recovery Myocardial T1-Mapping during Systole: Accurate and Robust Quantification in the Presence of Arrhythmia.

Myocardial T1-mapping, a cardiac magnetic resonance imaging technique, facilitates a quantitative measure of fibrosis which is linked to numerous cardiovascular symptoms. To overcome the problems of common techniques, including lack of accuracy and robustness against partial-voluming and heart-rate variability, we introduce a systolic saturation-recovery T1-mapping method. The Saturation-Pulse Prepared Heart-rate independent Inversion-Recovery (SAPPHIRE) T1-mapping method was modified to enable imaging during systole. Phantom measurements were used to evaluate the insensitivity of systolic T1-mapping towards heart-rate variability. In-vivo feasibility and accuracy were demonstrated in ten healthy volunteers with native and post-contrast T1-mappping during systole and diastole. To show benefits in the presence of RR-variability, six arrhythmic patients underwent native T1-mapping. Resulting systolic SAPPHIRE T1-values showed no dependence on arrhythmia in phantom (CoV < 1%). In-vivo, significantly lower T1 (1563 ± 56 ms, precision: 84.8 ms) and ECV-values (0.20 ± 0.03) than during diastole (T1 = 1580 ± 62 ms, p = 0.0124; precision: 60.2 ms, p = 0.03; ECV = 0.21 ± 0.03, p = 0.0098) were measured, with a strong correlation of systolic and diastolic T1 (r = 0.89). In patients, mis-triggering-induced motion caused significant imaging artifacts in diastolic T1-maps, whereas systolic T1-maps displayed resilience to arrythmia. In conclusion, the proposed method enables saturation-recovery T1-mapping during systole, providing increased robustness against partial-voluming compared to diastolic imaging, for the benefit of T1-measurements in arrhythmic patients.

Correction to: High sensitivity troponin T and I reflect mitral annular plane systolic excursion being assessed by cardiac magnetic resonance imaging.

Following publication of the original article [1], the authors reported that there was a mistake in the Methods section â†’ Measurements of biomarkers (page 6, line 3): 2000g should read 2500g. So, the correct sentence should be "All samples were obtained by venipuncture into serum monovettes® and centrifuged at 2500g for 10 min at 20 °C."