Inflammatory risk and cardiovascular events in patients without obstructive coronary artery disease: the ORFAN multicentre, longitudinal cohort study.

BACKGROUND: Coronary computed tomography angiography (CCTA) is the first line investigation for chest pain, and it is used to guide revascularisation. However, the widespread adoption of CCTA has revealed a large group of individuals without obstructive coronary artery disease (CAD), with unclear prognosis and management. Measurement of coronary inflammation from CCTA using the perivascular fat attenuation index (FAI) Score could enable cardiovascular risk prediction and guide the management of individuals without obstructive CAD. The Oxford Risk Factors And Non-invasive imaging (ORFAN) study aimed to evaluate the risk profile and event rates among patients undergoing CCTA as part of routine clinical care in the UK National Health Service (NHS); to test the hypothesis that coronary arterial inflammation drives cardiac mortality or major adverse cardiac events (MACE) in patients with or without CAD; and to externally validate the performance of the previously trained artificial intelligence (AI)-Risk prognostic algorithm and the related AI-Risk classification system in a UK population. METHODS: This multicentre, longitudinal cohort study included 40 091 consecutive patients undergoing clinically indicated CCTA in eight UK hospitals, who were followed up for MACE (ie, myocardial infarction, new onset heart failure, or cardiac death) for a median of 2·7 years (IQR 1·4-5·3). The prognostic value of FAI Score in the presence and absence of obstructive CAD was evaluated in 3393 consecutive patients from the two hospitals with the longest follow-up (7·7 years [6·4-9·1]). An AI-enhanced cardiac risk prediction algorithm, which integrates FAI Score, coronary plaque metrics, and clinical risk factors, was then evaluated in this population. FINDINGS: In the 2·7 year median follow-up period, patients without obstructive CAD (32 533 [81·1%] of 40 091) accounted for 2857 (66·3%) of the 4307 total MACE and 1118 (63·7%) of the 1754 total cardiac deaths in the whole of Cohort A. Increased FAI Score in all the three coronary arteries had an additive impact on the risk for cardiac mortality (hazard ratio [HR] 29·8 [95% CI 13·9-63·9], p<0·001) or MACE (12·6 [8·5-18·6], p<0·001) comparing three vessels with an FAI Score in the top versus bottom quartile for each artery. FAI Score in any coronary artery predicted cardiac mortality and MACE independently from cardiovascular risk factors and the presence or extent of CAD. The AI-Risk classification was positively associated with cardiac mortality (6·75 [5·17-8·82], p<0·001, for very high risk vs low or medium risk) and MACE (4·68 [3·93-5·57], p<0·001 for very high risk vs low or medium risk). Finally, the AI-Risk model was well calibrated against true events. INTERPRETATION: The FAI Score captures inflammatory risk beyond the current clinical risk stratification and CCTA interpretation, particularly among patients without obstructive CAD. The AI-Risk integrates this information in a prognostic algorithm, which could be used as an alternative to traditional risk factor-based risk calculators. FUNDING: British Heart Foundation, NHS-AI award, Innovate UK, National Institute for Health and Care Research, and the Oxford Biomedical Research Centre.

Cardiovascular disease in women: insights from magnetic resonance imaging.

The presentation and identification of cardiovascular disease in women pose unique diagnostic challenges compared to men, and underrecognized conditions in this patient population may lead to clinical mismanagement.This article reviews the sex differences in cardiovascular disease, explores the diagnostic and prognostic role of cardiovascular magnetic resonance (CMR) in the spectrum of cardiovascular disorders in women, and proposes the added value of CMR compared to other imaging modalities. In addition, this article specifically reviews the role of CMR in cardiovascular diseases occurring more frequently or exclusively in female patients, including Takotsubo cardiomyopathy, connective tissue disorders, primary pulmonary arterial hypertension and peripartum cardiomyopathy. Gaps in knowledge and opportunities for further investigation of sex-specific cardiovascular differences by CMR are also highlighted.

Measurement of myocardium at risk with cardiovascular MR: comparison of techniques for edema imaging.

PURPOSE: To determine variability and agreement for detecting myocardial edema with T2-weighted short-tau inversion recovery (STIR), acquisition for cardiac unified T2 edema (ACUT2E), T2 mapping, and early gadolinium enhancement (EGE) after successfully reperfused ST-segment-elevation myocardial infarction (STEMI) and diagnostic accuracy of each sequence to predict infarct-related artery (IRA). MATERIALS AND METHODS: Local ethics committee approved the study, with patient informed written consent. On day 2 after successful primary angioplasty for STEMI, 53 patients were prospectively enrolled; 40 patients (mean age, 60 years) completed study. Two sets of cardiac magnetic resonance (MR) images were obtained on same day 6 hours apart. Basal, midcavity, and apical sections were obtained with each sequence. Interobserver, intraobserver, and interimage variability (1 minus intraclass correlation coefficient) and agreement (Bland-Altman method) were assessed. RESULTS: Size of myocardial edema significantly differed. Mean size of myocardium at risk was similar between T2-weighted STIR (18.2 g) and T2 mapping (17.3 g) (P = .54). Mean size differed between T2-weighted STIR (18.2 g) and ACUT2E (14.0 g) (P = .01) and between T2-weighted STIR (18.2 g) and EGE (14.2 g) (P = .003). T2 mapping and EGE had best agreement (interobserver bias: T2-weighted STIR, -0.9 [mean difference] ± 9.6 [standard deviation]; ACUT2E, -2.5 ± 6.9; T2 mapping, -3.8 ± 4.7; EGE, -5.3 ± 5.9; interimage bias: T2-weighted STIR, 1.5 ± 5.8; ACUT2E, -0.8 ± 4.9; T2 mapping, 3.1 ± 4.0; EGE, 1.1 ± 4.9; intraobserver bias: T2-weighted STIR, 1.4 ± 5.8; ACUT2E, 0.6 ± 4.7; T2 mapping, 2.2 ± 3.1; EGE, 1.7 ± 2.9). Variability was lowest for T2 mapping (intraobserver, 0.05; interobserver, 0.09; interimage, 0.1) followed by EGE (intraobserver, 0.03; interobserver, 0.14; interimage, 0.14), with improved detection of territory of IRA versus ACUT2E (intraobserver, 0.11; interobserver, 0.22; interimage, 0.12) and T2-weighted STIR (intraobserver, 0.1; interobserver, 0.32; interimage, 0.1). CONCLUSION: Cardiac MR methods to detect and quantify infarct myocardial edema are not interchangeable; T2 mapping is the most reproducible method, followed by EGE, ACUT2E, and T2-weighted STIR. Clinical trial registration no. NCT01468662

Cost-effectiveness of a novel AI technology to quantify coronary inflammation and cardiovascular risk in patients undergoing routine Coronary Computed Tomography Angiography.

AIMS: Coronary Computed Tomography Angiography (CCTA) is a first line investigation for chest pain in patients with suspected obstructive coronary artery disease (CAD). However, many acute cardiac events occur in the absence of obstructive CAD. We assessed the lifetime cost-effectiveness of integrating a novel artificial intelligence-enhanced image analysis algorithm (AI-Risk) that stratifies the risk of cardiac events by quantifying coronary inflammation, combined with the extent of coronary artery plaque and clinical risk factors, by analysing images from routine CCTA. METHODS AND RESULTS: A hybrid decision-tree with population cohort Markov model was developed from 3,393 consecutive patients who underwent routine CCTA for suspected obstructive CAD and followed up for major adverse cardiac events over a median(IQR) of 7.7(6.4-9.1) years. In a prospective real-world evaluation survey of 744 consecutive patients undergoing CCTA for chest pain investigation, the availability of AI-Risk assessment led to treatment initiation or intensification in 45% of patients. In a further prospective study of 1,214 consecutive patients with extensive guideline recommended cardiovascular risk profiling, AI-Risk stratification led to treatment initiation or intensification in 39% of patients beyond the current clinical guideline recommendations. Treatment guided by AI-Risk modelled over a lifetime horizon could lead to fewer cardiac events (relative reductions of 4%, 4%, 11%, and 12% for myocardial infarction, ischaemic stroke, heart failure and cardiac death, respectively). Implementing AI-Risk classification in routine interpretation of CCTA is highly likely to be cost-effective (Incremental cost-effectiveness ratio £1,371-3,244), both in scenarios of current guideline compliance or when applied only to patients without obstructive CAD. CONCLUSIONS: Compared with standard care, the addition of AI-Risk assessment in routine CCTA interpretation is cost effective, by refining risk guided medical management.

The Use and Efficacy of FFR-CT: Real-World Multicenter Audit of Clinical Data With Cost Analysis.

BACKGROUND: Fractional flow reserve-computed tomography (FFR-CT) is endorsed by UK and U.S. chest pain guidelines, but its clinical effectiveness and cost benefit in real-world practice are unknown. OBJECTIVES: The purpose of this study was to audit the use of FFR-CT in clinical practice against England's National Institute for Health and Care Excellence guidance and assess its diagnostic accuracy and cost. METHODS: A multicenter audit was undertaken covering the 3 years when FFR-CT was centrally funded in England. For coronary computed tomographic angiograms (CCTAs) submitted for FFR-CT analysis, centers provided data on symptoms, CCTA and FFR-CT findings, and subsequent management. Audit standards included using FFR-CT only in patients with stable chest pain and equivocal stenosis (50%-69%). Diagnostic accuracy was evaluated against invasive FFR, when performed. Follow-up for nonfatal myocardial infarction and all-cause mortality was undertaken. The cost of an FFR-CT strategy was compared to alternative stress imaging pathways using cost analysis modeling. RESULTS: A total of 2,298 CCTAs from 12 centers underwent FFR-CT analysis. Stable chest pain was the main symptom in 77%, and 40% had equivocal stenosis. Positive and negative predictive values of FFR-CT were 49% and 76%, respectively. A total of 46 events (2%) occurred over a mean follow-up period of 17 months; FFR-CT (cutoff: 0.80) was not predictive. The FFR-CT strategy costs £2,102 per patient compared with an average of £1,411 for stress imaging. CONCLUSIONS: In clinical practice, the National Institute for Health and Care Excellence criteria for using FFR-CT were met in three-fourths of patients for symptoms and 40% for stenosis. FFR-CT had a low positive predictive value, making its use potentially more expensive than conventional stress imaging strategies.

Low-Dose Alteplase During Primary Percutaneous Coronary Intervention According to Ischemic Time.

BACKGROUND: Microvascular obstruction affects one-half of patients with ST-segment elevation myocardial infarction and confers an adverse prognosis. OBJECTIVES: This study aimed to determine whether the efficacy and safety of a therapeutic strategy involving low-dose intracoronary alteplase infused early after coronary reperfusion associates with ischemic time. METHODS: This study was conducted in a prospective, multicenter, parallel group, 1:1:1 randomized, dose-ranging trial in patients undergoing primary percutaneous coronary intervention. Ischemic time, defined as the time from symptom onset to coronary reperfusion, was a pre-specified subgroup of interest. Between March 17, 2016, and December 21, 2017, 440 patients, presenting with ST-segment elevation myocardial infarction within 6 h of symptom onset (<2 h, n = 107; ≥2 h but <4 h, n = 235; ≥4 h to 6 h, n = 98), were enrolled at 11 U.K. hospitals. Participants were randomly assigned to treatment with placebo (n = 151), alteplase 10 mg (n = 144), or alteplase 20 mg (n = 145). The primary outcome was the amount of microvascular obstruction (MVO) (percentage of left ventricular mass) quantified by cardiac magnetic resonance imaging at 2 to 7 days (available for 396 of 440). RESULTS: Overall, there was no association between alteplase dose and the extent of MVO (p for trend = 0.128). However, in patients with an ischemic time ≥4 to 6 h, alteplase increased the mean extent of MVO compared with placebo: 1.14% (placebo) versus 3.11% (10 mg) versus 5.20% (20 mg); p = 0.009 for the trend. The interaction between ischemic time and alteplase dose was statistically significant (p = 0.018). CONCLUSION: In patients presenting with ST-segment elevation myocardial infarction and an ischemic time ≥4 to 6 h, adjunctive treatment with low-dose intracoronary alteplase during primary percutaneous coronary intervention was associated with increased MVO. Intracoronary alteplase may be harmful for this subgroup. (A Trial of Low-Dose Adjunctive Alteplase During Primary PCI [T-TIME]; NCT02257294).

Native T1 mapping to detect extent of acute and chronic myocardial infarction: comparison with late gadolinium enhancement technique.

Investigate whether native-T1 mapping can assess the transmural extent of myocardial infarction (TEI) thereby differentiating viable from non-viable myocardium without the use of gadolinium-contrast in both acute and chronic myocardial infarction (aMI and cMI). Sixty patients (30 cMI > 1 year and 30 aMI day 2 STEMI) and 20 healthy-controls underwent 1.5 T CMR to assess left ventricular function (cine), native-T1 mapping (MOLLI sequence 5(3)3, motion-corrected) and the presence and TEI from late gadolinium enhancement (LGE) images. Segments with TEI > 75% was considered non-viable. Gold-standard LGE-TEI was compared with corresponding segmental native-T1. Segmental native-T1 correlated significantly with TEI (R = 0.74, p < 0.001 in cMI and R = 0.57, p < 0.001 in aMI). Native-T1 differentiated segments with no LGE (1031 ± 31 ms), LGE positive but viable (1103 ± 57 ms) and LGE positive but non-viable (1206 ± 118 ms) in cMI (p < 0.01). It also differentiated segments with no LGE (1054 ± 65 m), LGE positive but viable (1135 ± 73 ms) and LGE positive but non-viable (1168 ± 71 ms) in aMI (p < 0.01). ROC analysis demonstrated excellent accuracy of native-T1 mapping compared to LGE-TEI (AUC - 0.88, p < 0.001 in cMI, vs AUC - 0.83, p < 0.001 in aMI). Native-T1 performed better in cMI than aMI (p < 0.01). In cMI a segmental T1 threshold of 1085 ms differentiated viable from non-viable segments with a sensitivity 88% and specificity of 88% whereas a T1 of 1110 ms differentiated viable from nonviable with 79% sensitivity and 79% specificity in aMI. Native-T1 mapping correlates significantly with TEI thereby differentiating between normal, viable, and non-viable myocardium with distinctive T1 profiles in aMI and cMI. Native T1-mapping to detect MI performed better in cMI compared to aMI due to absence of myocardial oedema. Native-T1 mapping holds promise for viability assessment without the need for gadolinium-contrast agent.

Cangrelor versus Ticagrelor in Patients Treated with Primary Percutaneous Coronary Intervention: Impact on Platelet Activity, Myocardial Microvascular Function and Infarct Size: A Randomized Controlled Trial.

BACKGROUND: Oral P2Y12 inhibitors take more than 2 hours to achieve full effect in healthy subjects and this action is further delayed in patients with acute myocardial infarction. Intravenous P2Y12 inhibition might lead to more timely and potent anti-platelet effect in the context of emergency primary angioplasty, improving myocardial recovery. OBJECTIVES: This article compares the efficacy of intravenous cangrelor versus ticagrelor in a ST-elevation myocardial infarction (STEMI) population treated with primary percutaneous coronary intervention (PPCI). MATERIALS AND METHODS: In an open-label, prospective, randomized controlled trial, 100 subjects with STEMI were assigned 1:1 to intravenous cangrelor or oral ticagrelor. The co-primary endpoints were platelet P2Y12 inhibition at infarct vessel balloon inflation time, 4 and 24 hours. Secondary endpoints included indices of coronary microcirculatory function: index of microvascular resistance (IMR), initial infarct size (troponin at 24 hours) and final infarct size at 12 weeks (cardiac magnetic resonance). Secondary endpoints included indices of coronary microcirculatory function (index of microvascular resistance [IMR]), initial infarct size (troponin at 24 hours), final infarct size at 12 weeks (cardiac magnetic resonance), corrected thrombolysis in myocardial infarction (TIMI) frame count, TIMI flow grade, myocardial perfusion grade, and ST-segment resolution (ClinicalTrials.gov NCT02733341). RESULTS: P2Y12 inhibition at first balloon inflation time was significantly greater in cangrelor-treated patients (cangrelor P2Y12 reaction unit [PRU] 145.2 ± 50.6 vs. ticagrelor 248.3 ± 55.1). There was no difference in mean PRU at 4 and 24 to 36 hours post-dosing. IMR, final infarct size, angiographic and electrocardiographic measures of reperfusion were all similar between groups. CONCLUSION: Cangrelor produces more potent P2Y12 inhibition at the time of first coronary balloon inflation time compared with ticagrelor. Despite this enhanced P2Y12 inhibition, coronary microvascular function and final infarct size did not differ between groups.

A Multicenter, Scan-Rescan, Human and Machine Learning CMR Study to Test Generalizability and Precision in Imaging Biomarker Analysis.

BACKGROUND: Automated analysis of cardiac structure and function using machine learning (ML) has great potential, but is currently hindered by poor generalizability. Comparison is traditionally against clinicians as a reference, ignoring inherent human inter- and intraobserver error, and ensuring that ML cannot demonstrate superiority. Measuring precision (scan:rescan reproducibility) addresses this. We compared precision of ML and humans using a multicenter, multi-disease, scan:rescan cardiovascular magnetic resonance data set. METHODS: One hundred ten patients (5 disease categories, 5 institutions, 2 scanner manufacturers, and 2 field strengths) underwent scan:rescan cardiovascular magnetic resonance (96% within one week). After identification of the most precise human technique, left ventricular chamber volumes, mass, and ejection fraction were measured by an expert, a trained junior clinician, and a fully automated convolutional neural network trained on 599 independent multicenter disease cases. Scan:rescan coefficient of variation and 1000 bootstrapped 95% CIs were calculated and compared using mixed linear effects models. RESULTS: Clinicians can be confident in detecting a 9% change in left ventricular ejection fraction, with greater than half of coefficient of variation attributable to intraobserver variation. Expert, trained junior, and automated scan:rescan precision were similar (for left ventricular ejection fraction, coefficient of variation 6.1 [5.2%-7.1%], P=0.2581; 8.3 [5.6%-10.3%], P=0.3653; 8.8 [6.1%-11.1%], P=0.8620). Automated analysis was 186× faster than humans (0.07 versus 13 minutes). CONCLUSIONS: Automated ML analysis is faster with similar precision to the most precise human techniques, even when challenged with real-world scan:rescan data. Assessment of multicenter, multi-vendor, multi-field strength scan:rescan data (available at www.thevolumesresource.com) permits a generalizable assessment of ML precision and may facilitate direct translation of ML to clinical practice.

Microvascular dysfunction determines infarct characteristics in patients with reperfused ST-segment elevation myocardial infarction: The MICROcirculation in Acute Myocardial Infarction (MICRO-AMI) study.

BACKGROUND: In patients with reperfused ST-elevation myocardial infarction (STEMI) both invasive and non-invasive assessments of microvascular dysfunction, the index of microcirculatory resistance (IMR), and microvascular obstruction (MVO) by cardiovascular magnetic resonance (CMR), independently predict poor long-term outcomes. AIMS: The aims of this study were to investigate whether an invasive parameter (IMR), assessed at the time of primary percutaneous intervention (PPCI), could predict the extent of MVO in proportion to infarct size (MVO index). METHODS: 50 patients presenting with STEMI and TIMI flow ≤ I in the infarct related artery were prospectively recruited to the study, before undergoing PPCI. All patients underwent invasive IMR assessment at maximal hyperaemia using adenosine, and following stent insertion. CMR was performed on day 2 following STEMI, MVO was assessed both on first-pass rest perfusion (early MVO) and in the late gadolinium enhancement (LGE) images (late MVO) along with infarct size. The MVO index was calculated as the ratio of late MVO/infarct size. Differences between IMR quartiles and the MVO index were investigated. RESULTS: The median IMR was 38.5 (range 9 to 202). The median size of late MVO was 1.9% LV (range 0 to 21.0% LV). IMR predicted late MVO (p<0.01) and as IMR increased, the MVO index increased (r = 0.70, [95% CI 0.53, 0.82], p<0.001). An IMR cut-off of 40 significantly predicted the presence of late MVO on CMR (p<0.001). CONCLUSION: IMR measured at the time of PPCI in acutely reperfused STEMI is associated with the presence and severity of infarct damage as measured by the MVO index. TRIAL REGISTRATION: The Microcirculation in Acute Myocardial Infarction (MICRO-AMI). Clinicaltrials.gov NCT01552564. Registered 9th March 2012.

Formal consensus to identify clinically important changes in management resulting from the use of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway.

OBJECTIVE: To define important changes in management arising from the use of cardiovascular magnetic resonance (CMR) in patients who activate the primary percutaneous coronary intervention (PPCI) pathway. DESIGN: Formal consensus study using literature review and cardiologist expert opinion to formulate consensus statements and setting up a consensus panel to review the statements (by completing a web-based survey, attending a face-to-face meeting to discuss survey results and modify the survey to reflect group discussion and completing the modified survey to determine which statements were in consensus). PARTICIPANTS: Formulation of consensus statements: four cardiologists (two CMR and two interventional) and six non-clinical researchers. Formal consensus: seven cardiologists (two CMR and three interventional, one echocardiography and one heart failure). Forty-nine additional cardiologists completed the modified survey. RESULTS: Thirty-seven draft statements describing changes in management following CMR were generated; these were condensed into 12 statements and reviewed through the formal consensus process. Three of 12 statements were classified in consensus in the first survey; these related to the role of CMR in identifying the cause of out-of-hospital cardiac arrest, providing a definitive diagnosis in patients found to have unobstructed arteries on angiography and identifying patients with left ventricular thrombus. Two additional statements were in consensus in the modified survey, relating to the ability of CMR to identify patients who have a poor prognosis after PPCI and assess ischaemia and viability in patients with multivessel disease. CONCLUSION: There was consensus that CMR leads to clinically important changes in management in five subgroups of patients who activate the PPCI pathway.

The effect of reducing spatial resolution by in-plane partial volume averaging on peak velocity measurements in phase contrast magnetic resonance angiography.

BACKGROUND: The aim of this study was to quantify the degree of the effect of in-plane partial volume averaging on recorded peak velocity in phase contrast magnetic resonance angiography (PCMRA). METHODS: Using cardiac optimized 1.5 Tesla MRI scanners (Siemens Symphony and Avanto), 145 flow measurements (14 anatomical locations; ventricular outlets, aortic valve (AorV), aorta (5 sites), pulmonary arteries (3 sites), pulmonary veins, superior and inferior vena cava)- in 37 subjects (consisting of healthy volunteers, congenital and acquired heart disease patients) were analyzed by Siemens Argus default voxel averaging technique (where peak velocity = mean of highest velocity voxel and four neighbouring voxels) and by single voxel technique (1.3×1.3×5 or 1.7×1.7×5.5 mm3) (where peak velocity = highest velocity voxel only). The effect of scan protocol (breath hold versus free breathing) and scanner type (Siemens Symphony versus Siemens Avanto) were also assessed. Statistical significance was defined as P<0.05. RESULTS: There was a significant mean increase in peak velocity of 7.1% when single voxel technique was used compared to voxel averaging (P<0.0001). Significant increases in peak velocity were observed by single voxel technique compared to voxel averaging regardless of subject type, anatomical flow location, scanner type and breathing command. Disabling voxel averaging did not affect the volume of flow recorded. CONCLUSIONS: Reducing spatial resolution by the use of voxel averaging produces a significant underestimation of peak velocity. While this is of itself not surprising this is the first report to quantify the size of the effect. When PCMRA is used to assess peak velocity recording pixel averaging should be disabled.

Quantification of infarct size and myocardium at risk: evaluation of different techniques and its implications.

AIMS: The aim of this study was to evaluate seven methods for quantifying myocardial oedema [2 standard deviation (SD), 3 SD, 5 SD, full width at half maximum (FWHM), Otsu method, manual thresholding, and manual contouring] from T2-weighted short tau inversion recovery (T2w STIR) and also to reassess these same seven methods for quantifying acute infarct size following ST-segment myocardial infarction (STEMI). This study focuses on test-retest repeatability while assessing inter- and intraobserver variability. T2w STIR and late gadolinium enhancement (LGE) are the most widely used cardiovascular magnetic resonance (CMR) techniques to image oedema and infarction, respectively. However, no consensus exists on the best quantification method to be used to analyse these images. This has potential important implications in the research setting where both myocardial oedema and infarct size are increasingly used and measured as surrogate endpoints in clinical trials. METHODS AND RESULTS: Forty patients day 2 following acute reperfused STEMI were scanned for myocardial oedema and infarction (LGE). All patients had a second CMR scan on the same day >6 h apart from the first one. Images were analysed offline by two independent observers using the semi-automated software. Both oedema and LGE were quantified using seven techniques (2 SD, 3 SD, 5 SD, Otsu, FWHM, manual threshold, and manual contouring). Interobserver, intraobserver and test-retest agreement and variability for both infarct size and oedema quantification were assessed. Infarct size and myocardial quantification vary depending on the quantification method used. Overall, manual contouring provided the lowest inter-, intraobserver, and interscan variability for both infarct size and oedema quantification. The FWHM method for infarct size quantification and the Otsu method for myocardial oedema quantification are acceptable alternatives. CONCLUSIONS: This study determines that, in acute myocardial infarction (MI), manual contouring has the lowest overall variability for quantification of both myocardial oedema and MI when analysed by experienced observers.

The impact of infarct size on regional and global left ventricular systolic function: a cardiac magnetic resonance imaging study.

Myocardial infarction (MI) results in myocardial scarring which can have an impact on left ventricular (LV) stiffness and contractile function, ultimately leading to reduced LV systolic function and LV remodelling, However some concerns about the relation between scar extension and segmental wall motion contractility is not enough clear. Thus, the association between myocardial scar, LV regional and global function and LV remodeling should be investigated. We studied the relationship between scar extension, wall motion score index (WMSI), LV dimensions and systolic function in a group of patients with previous MI by cardiac magnetic resonance (CMR). 133 patients with previous (>6 month) MI were retrospectively enrolled in the study. Indexed end-systolic volume (ESVi), indexed end-diastolic volume (EDVi), LV ejection fraction (EF), stroke volume (SV), LV mass were measured using CMR. WMSI and sum scar score (SSS) were also measured following AHA\ACC criteria giving an arbitrary cut-off to distinguish larger from restricted late gadolinium enhancement (LGE) area. A total of 2261 segments were studied: regional wall motion abnormalities were present in 1032 segments (45%) and 724 (32%) showed presence of MI (LGE). WMSI correlated significantly with EF (r = -0.87, p < 0.0001) in all patients and in both patients with EF ≥ 40% (r = -0.77, p < 0.0001) and EF < 40% (r = -0.68, p < 0.0001). WMSI also correlated significantly with SSS (r = 0.57, p < 0.0001). The correlation between WMSI and SSS was more significant in patients with transmural MI (WMSI 2.1 ± 0.5 and SSS 17 ± 8; r = 0.55, p < 0.0001) than with non transmural MI (WMSI 1.6 ± 0.7 and SSS 6 ± 4; r = 0.34 and p = 0.02). A significant correlation was also found between EF and SSS (r = -0.55 and p < 0.0001) and between SSS and LV indexed volumes (EDVi; r = 0.44, p < 0.0001 and ESVi; r = 0.51, p < 0.0001). Infarct transmurality and extension as expressed as SSS assessed with cardiac MRI has an impact on global and regional systolic function. A multi-parametric score measuring WMSI scar transmurality and extension, could better identify an increased cardiac remodeling after coronary event.

Optimising the imaging plane for right ventricular magnetic resonance volume analysis in adult patients referred for assessment of right ventricular structure and function.

INTRODUCTION: Our aim was to evaluate the reproducibility and accuracy of using short-axis and axial (transaxial) plane for magnetic resonance imaging analysis in adult patients referred for assessment of right ventricular (RV) structure and function. METHODS: Twenty consecutive subjects (10 male, 10 female, mean age 32.2 ± 14.8 years) who were referred for RV assessment and had cardiac magnetic resonance imaging were retrospectively selected. Axial and short-axis manual contouring was performed using cine steady-state free precession sequences by three experienced imaging specialists. The reproducibility of end diastolic volumes, end systolic volumes and ejection fraction was assessed with intraclass correlation coefficients (ICCs) and paired t-tests. Left ventricular stroke volume (LVSV) and RV stroke volumes (RVSV) were compared with concordance correlation coefficients (CCCs) and t-tests to determine accuracy. RESULTS: The concordance between the RVSV and LVSV was good using both methods (axial RVSV CCC = 0.93, short-axis RVSV CCC = 0.86). Paired t-test and analysis of variance showed that the LV/RV stroke volume differences were not significant (p = 0.17). There was slight improvement in interobserver reliability with end systolic volume measurements (axial ICC = 0.92, short-axis ICC = 0.81) but this failed to reach statistical significance (p = 0.37). There was excellent intraobserver variability (ICC > 0.9). CONCLUSION: This study shows that there is no statistically significant difference in reproducibility or accuracy using the short-axis or axial orientations in RV volume analysis in adult patients being referred for RV assessment.

A Novel Cause of Acute Coronary Syndrome Due to Dynamic Extrinsic Coronary Artery Compression by a Rib Exostosis: Multimodality Imaging Diagnosis.

We report a case of acute coronary syndrome secondary to intermittent extrinsic compression of the left anterior descending coronary artery by inward-pointing rib exostosis in an 18-year-old woman during forceful repeated expiration in labour. The diagnosis was achieved using multimodality noninvasive cardiac imaging. In particular, we demonstrated the novel role of expiratory-phase cardiac computed tomography in confirming the anatomical relationship of the bony exostosis to the left anterior descending coronary artery. The case reminds us the heart and mediastinum move dynamically, relative to the bony thorax, throughout the respiratory cycle, and that changes in cardiac physiology in pregnancy may become pathological.

Diagnosing cardiac involvement in the hypereosinophilic syndrome by cardiac magnetic resonance.

Hypereosinophilic syndrome is characterized by unexplained hypereosinophilia involving different organ systems. The investigators present a patient diagnosed with hypereosinophilic syndrome in which cardiac magnetic resonance was pivotal in establishing the presence of cardiac involvement.