Myocardial Magnetic Resonance Research Articles

Germline HAVCR2/TIM-3 Checkpoint Inhibitor Receptor Deficiency in Recurrent Autoinflammatory Myocarditis

Myocarditis can be caused by viral infection, drug reaction or general inflammatory condition. To provide understanding on inflammatory myocarditis, we describe clinical, genetic, and immunological properties of a young male patient who suffered from recurrent myocarditis episodes since the age of four years. Electrocardiography, troponin I/T, echocardiography, myocardial magnetic resonance imaging and histological findings were consistent with recurrent myocarditis episodes. Homozygous c.245 A > G p.Tyr82Cys pathogenic variant in Hepatitis A Virus Cellular Receptor 2 (HAVCR2) gene encoding T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) receptor was found. Peripheral blood mononuclear cells were collected when the patient was asymptomatic; CD4+ and CD8+ T lymphoblasts, CD56+ natural killer cells and CD14+ monocytes were negative for surface TIM-3 expression. In vitro, TLR4 mediated interleukin-1β (IL-1β) response was high after LPS/ATP stimulation. Clinical symptoms responded to IL-1 receptor antagonist anakinra. TIM-3 p.Tyr82Cys CD4+ and CD8+ T cell proliferation in vitro was unrestrained. Findings on IL-2, interferon gamma, regulatory T cells, signal transducer and activator of transcription (STAT) 1, 3 and 4 phosphorylation, and PD-1 and LAG-3 checkpoint inhibitor receptor analyses were comparable to controls. We conclude that TIM-3 deficiency due to homozygous HAVCR2 c.245 A > G p.Tyr82Cys pathogenic variant in the patient described here is associated with autoinflammatory symptoms limited to early onset recurrent febrile myocarditis. Excessive IL-1β production and defective regulation of T cell proliferation may contribute to this clinical condition responsive to anakinra treatment.

Heart failure with preserved ejection fraction in post myocardial infarction patients: a myocardial magnetic resonance (MR) tissue tracking study.

This study aimed to explore the value of cardiac magnetic resonance tissue tracking (CMR-TT) technology in evaluating heart failure with preserved ejection fraction (HFpEF) in patients with chronic myocardial infarction (CMI). Between June 2016 and March 2022, we included a consecutive series of 92 patients with CMI and 40 healthy controls in this retrospective study. The CMI patients enrolled were divided into different subgroups [HFpEF-CMI group (n=54) and non- heart failure (HF)-CMI group (n=38)] according to the Heart Failure Association (HFA)-PEFF (step 1: P, pre-test assessment; step 2: E, echocardiography and natriuretic peptide score; step 3: F1, functional testing; step 4: F2, final aetiology) diagnostic algorithm. CMR scan was performed at the First Hospital of China Medical University. Quantitative measurements of myocardial damage, such as myocardial strain parameters of both ventricles derived by CMR-TT and infarct size and transmurality by late gadolinium enhancement (LGE), were assessed. One-way analysis of variance, independent samples t-test, and rank sum test were used to compare myocardial impairment among groups. Pearson or Spearman correlation coefficient was used to measure correlations between left ventricular (LV) strains and clinical and functional parameters. Logistic regression analysis and receiver operating characteristic (ROC) curve were performed to identify the best parameter for diagnosing HFpEF-CMI. HFpEF-CMI patients demonstrated significantly impaired LV strains and strain rates in all of the three directions (radial, circumferential and longitudinal) compared to non-HF-CMI patients and healthy controls (P<0.001 for all), whereas only global longitudinal strain (GLS) was significantly impaired in HFpEF-CMI patients vs. controls for right ventricular strain parameters (P<0.001). LV strains showed moderate correlation with N-terminal pro-brain natriuretic peptide (radial, circumferential and longitudinal strain, R=-0.401, R=0.408, R=0.407, respectively, P<0.001 for all). LV strains in the three directions (radial, circumferential and longitudinal) [area under ROC curve (AUC) =0.707, 95% confidence interval (CI): 0.603-0.797; AUC =0.708, 95% CI: 0.604-0.798; AUC =0.731, 95% CI: 0.628-0.818; respectively, P<0.01 for all] were discriminators for HFpEF-CMI and non-HF-CMI. LV strains and myocardial infarction volume were independent factors in multi-logistic regression analysis after adjusting for body mass index, age, and sex (P<0.05 for all). CMR-TT provides clinicians with useful additional imaging parameters to facilitate the assessment of CMI patients with HFpEF. LV strain parameters can detect early cardiac insufficiency in patients with HFpEF-CMI and have potential value for discriminating between HFpEF and non-HF patients post-CMI.

A comparison of myocardial magnetic resonance extracellular volume mapping at 3 T against histology of tissue collagen in severe aortic valve stenosis and obstructive hypertrophic cardiomyopathy

ObjectiveQuantitative extracellular volume fraction (ECV) mapping with MRI is commonly used to investigate in vivo diffuse myocardial fibrosis. This study aimed to validate ECV measurements against ex vivo histology of myocardial tissue samples from patients with aortic valve stenosis or hypertrophic cardiomyopathy.Materials and methodsSixteen patients underwent MRI examination at 3 T to acquire native T1 maps and post-contrast T1 maps after gadobutrol administration, from which hematocrit-corrected ECV maps were estimated. Intra-operatively obtained myocardial tissue samples from the same patients were stained with picrosirius red for quantitative histology of myocardial interstitial fibrosis. Correlations between in vivo ECV and ex vivo myocardial collagen content were evaluated with regression analyses.ResultsSeptal ECV was 30.3% ± 4.6% and correlated strongly (n = 16, r = 0.70; p = 0.003) with myocardial collagen content. Myocardial native T1 values (1206 ± 36 ms) did not correlate with septal ECV (r = 0.41; p = 0.111) or with myocardial collagen content (r = 0.32; p = 0.227).DiscussionWe compared myocardial ECV mapping at 3 T against ex vivo histology of myocardial collagen content, adding evidence to the notion that ECV mapping is a surrogate marker for in vivo diffuse myocardial fibrosis.

BMAnet: Boundary Mining With Adversarial Learning for Semi-Supervised 2D Myocardial Infarction Segmentation.

Automatic segmentation of myocardial infarction (MI) regions in late gadolinium-enhanced cardiac magnetic resonance images is an essential step in the computed diagnosis of myocardial infarction. Most of the current myocardial infarction region segmentation methods are based on fully supervised deep learning. However, cardiologists' annotation of myocardial infarction regions in cardiac magnetic resonance images during the diagnosis process is time-consuming and expensive. This paper proposes a semi-supervised myocardial infarction segmentation. It consists of two models: 1) a boundary mining model and 2) an adversarial learning model. The boundary mining model can solve the boundary ambiguity problem by enlarging the gap between the foreground and background features, thus segmenting the myocardial infarction region accurately. The adversarial learning model can make the boundary mining model learn from additional unlabeled data by evaluating the segmentation performance and providing pseudo supervision, which significantly increases the robustness of the boundary mining model. We conduct extensive experiments on an in-house myocardial magnetic resonance dataset. The experimental results on six evaluation metrics demonstrate that our method achieves excellent results in myocardial infarction segmentation and outperforms the state-of-the-art semi-supervised methods.

Myocarditis following administration of COVID-19 Vaccine: Should we be worried?

The COVID-19 vaccines have raised scepticism surrounding their accelerated approval due to their suspected adverse side effects.(1) Recently emerging clinical cases such as flu, fever, tachycardia, Bell’s palsy, and swelling of the lymph nodes have further heightened public distrust. Interestingly, the United States Food and Drug Administration has recently announced an inflammatory heart disease, Myocarditis, as a potential risk of the Pfizer-BioNTech COVID-19 vaccine. In efforts to find an association between the Pfizer vaccine and Myocarditis, researchers recently carried out extensive clinical trials; two new studies tracked cases having biomarker evidence of myocardial injury and Cardiac Magnetic Resonance Imaging.(2,3) Moreover, the United States Centers for Disease Control and Prevention (CDC) has recorded 323 confirmed cases of myocarditis, most documented within a week after each patient had received the Pfizer-BioNTech COVID-19 vaccine.(4) A recent emergent theory suggests a cytokine response as the leading cause of myocarditis; the immune system identifies the mRNA in the vaccine as an antigen, leading to the activation of proinflammatory cascades and immunological pathways. The expression of cytokines and activation markers is due to the exposure of the dendritic cells to mRNA, which eventually causes inflammation of the heart muscle.(4) Furthermore, according to the CDC, the myocarditis is mainly observed in male adolescents and young adults, more often after getting the second dose of the COVID-19 vaccine. A week after administrating the vaccine, symptoms such as chest pain, shortness of breath, and tachycardia may appear, which tend to resolve following conservative treatment with nonsteroidal anti-inflammatory drugs.(3) Despite the previously mentioned occurrences of myocarditis after administration of the Pfizer-BioNtech vaccine, we would like to highlight the results of a large-scale cohort study in Israel with 2.5 million participants, where the estimated incidence of myocarditis after the administration of the Pfizer vaccine was only 2.13 cases per 100,000 persons.(5) These statistics allow us to draw the readers’ attention towards the benefits of the COVID-19 vaccination, which outweigh potential adverse risks such as Myocarditis. The Pfizer-BioNtech vaccine has proven to be 95% effective and to keep track of other possible complications, patients are advised to report to the Vaccine Adverse Event Reporting System (VAERS) to document any unusual side effects.(4) Despite the few reported complications, we would further like to emphasize the importance of population- wide vaccination to overcome the COVID-19 pandemic with a minimum mortality rate.

Sulfonylureas Use Is Not Associated With Increased Infarct Size in Patients With Type 2 Diabetes and ST-Segment Elevation Myocardial Infarction.

Aims: This retrospective study assessed the association between sulfonylureas use and infarct size in patients with type 2 diabetes (T2DM) and ST-segment elevation myocardial infarction (STEMI) by myocardial enzymology indexes and cardiac magnetic resonance (CMR) imaging.Methods: Patients presenting STEMI between July 2013 and August 2019 were included in a retrospective database at our institution. Antidiabetic agents used before STEMI were recorded. Patients with maximum recorded troponin I (max cTNI) and creatine phosphokinase isoenzyme (CK-MB) within the first 72 h of chest pain onset were selected. Infarct size was quantified by CMR imaging, and cardiovascular outcomes were also obtained at 30 days and 6 months follow-up. Multivariable regression models explored potential risk factors associated with infarct size and clinical outcomes.Results: A total of 254 T2DM and STEMI patients were included, with 101 sulfonylurea users and 153 non-users. Sulfonylureas users were not associated with higher max cTnI and max CK-MB compared to non-users. Among 65 CMR patients, no significant differences in infarct size were detected between sulfonylureas users and non-users. Whereas, the incidence of microvascular obstruction (MVO) was higher in patients receiving sulfonylureas than those taking non-sulfonylureas (88.0 vs. 62.5%, p = 0.023). No higher cardiovascular events of sulfonylureas users vs. non-users were observed, except for heart failure events (24.0 vs. 2.5% at 30 days, p = 0.011; 28.0 vs. 2.5% at 6 months, p = 0.004). Multivariable regression analyses verified that sulfonylureas users increased the risks of MVO.Conclusions: Sulfonylureas use did not associate with larger infarct size in patients with T2DM and STEMI. A potentially higher incidence of MVO in sulfonylurea users was found. Notably, since most patients presented after a relatively long period of ischemia and glibenclamide was not used by the included patients in this observational study, the results of this study should not be extrapolated to clinical settings with short periods of ischemia or to patients using glibenclamide.

Comparison of Magnetic Resonance Imaging T2 Results in Beta-Thalassemia Patients Treated by Deferasirox or Combination of Deferoxamine and Deferiprone

Background: Iron extra load is an anticipated and lethal consequence of chronic blood transfusion in major beta-thalassemia patients; therefore it is necessary to use an efficient iron chelator drug to stimulate the evacuation of the surplus iron from the body. This trial was performed to compare myocardial and hepatic magnetic resonance imaging T2 (MRI T2*) results of beta-thalassemia patients treated by Deferasirox or combination of Deferoxamine and Deferiprone.&#x0D; Material and Methods: In this clinical trial, 44 patients who were on combination therapy with Deferiprone and Deferoxamine and complied with the inclusion criteria were randomized to either case (Deferasirox) or control (combined therapy) groups. Twenty-two patients in the case group received Deferasirox. For 22 patients in the control group, prior treatment with Deferiprone and Deferoxamine was continued. Myocardial and hepatic MRI T2* results were assessed before and after the study. Moreover, serum ferritin level (SFL) was evaluated every 3 months.&#x0D; Results: SFL at the start of the study did not differ significantly in two groups (2158.1± 1012.2 μg/L in the control group vs. 2145.5±1121.4 μg/L in the case group) (P=0.08). SFL at the end of the study did not differ significantly in two groups (2204.4±1143.5 μg/L in the control group vs. 2347.2±1236.6 μg/L in the case group), either (P=0.12). In each group, myocardial and hepatic MRI T2 at the start and at the end of the trial did not differ significantly (P&gt;0.1).&#x0D; Conclusion: Myocardial and hepatic MRI T2*results were better in the control (combination therapy) group than those in the case (Deferasirox) group. Major beta-thalassemia patients replied to combined treatment better than Deferasirox.

Native myocardial T1 time can predict development of subsequent anthracycline-induced cardiomyopathy.

AimsThis study aims to assess subclinical changes in functional and morphological myocardial magnetic resonance parameters very early into an anthracycline treatment, which may predict subsequent development of anthracycline‐induced cardiomyopathy (aCMP).Methods and resultsThirty sarcoma patients with planned anthracycline‐based chemotherapy (360–400 mg/m2 doxorubicin‐equivalent) were recruited. Median treatment time was 19.1 ± 2.1 weeks. Enrolled individuals received three cardiovascular magnetic resonance studies (before treatment, 48 h after first anthracycline treatment, and upon completion of treatment). Native T1 mapping (modified Look–Locker inversion recovery 5s(3s)3s), T2 mapping, and extracellular volume maps were acquired in addition to a conventional cardiovascular magnetic resonance with steady‐state free precession cine imaging at 1.5 T. Patients were given 0.2 mmol/kg gadoteridol for extracellular volume quantification and late gadolinium enhancement imaging. Development of relevant aCMP was defined as drop of left ventricular ejection fraction (LVEF) by >10%. For analysis, 23 complete data sets were available. Nine patients developed aCMP with LVEF reduction >10% until end of chemotherapy. Baseline LVEF was not different between patients with and without subsequent aCMP. When assessed 48 h after first dose of antracyclines, patients with subsequent aCMP had significantly lower native myocardial T1 times compared with before therapy (1002.0 ± 37.9 vs. 956.5 ± 29.2 ms, P < 0.01) than patients who did not develop aCMP (990.9 ± 56.4 vs. 978.4 ± 57.4 ms, P > 0.05). Patients with aCMP had decreased left ventricular mass upon completion of therapy (86.9 ± 24.5 vs. 81.1 ± 22.3 g; P = 0.02), while patients without aCMP did not show a change in left ventricular mass (81.8 ± 21.0 vs. 79.2 ± 18.1 g; P > 0.05). No patient developed new myocardial scars or compact myocardial fibrosis under chemotherapy.ConclusionsEarly decrease of T1 times 48 h after first treatment with anthracyclines can predict the development of subsequent aCMP after completion of chemotherapy.

Automatic localization of anatomical landmarks in cardiac MR perfusion using random forests

Abstract Automatic localization of anatomical landmarks in myocardial perfusion magnetic resonance (MR) data is considered to be a preliminary step toward fully automatic quantification of regional upslope or blood flow in the myocardium. The goal of this work is to develop an automatic method based on supervised learning and detect anatomical landmarks with high accuracy from myocardial perfusion MR data. Dynamic contrast enhanced myocardial MR perfusion data were acquired using a standard perfusion sequence. To effectively extract characteristic features for left ventricle (LV) center point and anterior right ventricle (RV) insertion point, we performed feature extraction of the two landmarks independently from an LV enhancement frame and an RV enhancement frame. Feature extraction of pixel intensity, Sobel gradient, and Haar-like features was performed. Cross-validation from training data was used to build a random forests classifier. We used 38 subjects’ data as training datasets and 21 subjects’ data as test datasets. The proposed method provided high accuracy in localization of the LV center point and anterior RV insertion point. The mean (±SD) localization errors of the proposed method were 3.38 (±2.36) mm for the LV center point and 4.23 (±1.97) mm for the anterior RV insertion point. The proposed method shows the potential to automatically localize anatomical landmarks for the segmental analysis of myocardial perfusion in MRI.

A semiautomatic method for rapid segmentation of velocity-encoded myocardial magnetic resonance imaging data.

To develop a semiautomatic method for rapid segmentation of myocardial tissue phase mapping (TPM) data. Manual segmentation of the myocardium was performed at end-diastole and end-systole. The points in both user-defined masks were then automatically tracked over the entire cardiac cycle using temporal integration of the velocity field. Paths that failed to visit both masks at the expected times were excluded, after which masks for all time points were generated automatically from the accepted paths. Midventricular and basal phase contrast TPM slices from 12 rats were segmented using the proposed method and fully manual segmentation. The results were compared using Dice's metric and Bland-Altman analysis, and interobserver variability was assessed. The semiautomatic method reduced the average user input time from 21 min to 1 min per slice. The Dice metrics between the methods were 0.88 ± 0.03 (midventricular) and 0.83 ± 0.06 (basal), and Bland-Altman limits of agreement of peak systolic and diastolic regional velocities were: midventricular: 0.05 ± 0.65 cm/s, -0.02 ± 0.42 cm/s, and -0.03 ± 0.40 cm/s (radial, tangential, longitudinal); basal: -0.04 ± 0.73 cm/s, 0.03 ± 0.60 cm/s, and -0.04 ± 0.48 cm/s (radial, tangential, longitudinal). Interobserver variability following semiautomatic segmentation was lower than for manual segmentation. The proposed method reduced the segmentation time substantially and exhibited well-preserved data quality and excellent interobserver limits of agreement. Magn Reson Med 78:1199-1207, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Patient-specific coronary blood supply territories for quantitative perfusion analysis

Myocardial perfusion imaging, coupled with quantitative perfusion analysis, provides an important diagnostic tool for the identification of ischaemic heart disease caused by coronary stenoses. The accurate mapping between coronary anatomy and under-perfused areas of the myocardium is important for diagnosis and treatment. However, in the absence of the actual coronary anatomy during the reporting of perfusion images, areas of ischaemia are allocated to a coronary territory based on a population-derived 17-segment (American Heart Association) AHA model of coronary blood supply. This work presents a solution for the fusion of 2D Magnetic Resonance (MR) myocardial perfusion images and 3D MR angiography data with the aim to improve the detection of ischaemic heart disease. The key contribution of this work is a novel method for the mediated spatiotemporal registration of perfusion and angiography data and a novel method for the calculation of patient-specific coronary supply territories. The registration method uses 4D cardiac MR cine series spanning the complete cardiac cycle in order to overcome the under-constrained nature of non-rigid slice-to-volume perfusion-to-angiography registration. This is achieved by separating out the deformable registration problem and solving it through phase-to-phase registration of the cine series. The use of patient-specific blood supply territories in quantitative perfusion analysis (instead of the population-based model of coronary blood supply) has the potential of increasing the accuracy of perfusion analysis. Quantitative perfusion analysis diagnostic accuracy evaluation with patient-specific territories against the AHA model demonstrates the value of the mediated spatiotemporal registration in the context of ischaemic heart disease diagnosis.

BEST ORAL ABSTRACTS1575Extracellular volume associates with outcomes more strongly than native or post-contrast myocardial T11507Cardiac Magnetic Resonance measured Extracellular Volume Independently Predicts Adverse Outcome in Heart Failure with Preserved Ejection Fraction1457Cardiac MRI Under Percussive Ventilation: A New Promising Technique1644Histological Validation of Cardiac Magnetic Resonance for the Evaluation of Myocardial Fibrosis after Heart Transplantation in Children1493First Pass Perfusion Reserve Index in

BEST ORAL ABSTRACTS1575Extracellular volume associates with outcomes more strongly than native or post-contrast myocardial T11507Cardiac Magnetic Resonance measured Extracellular Volume Independently Predicts Adverse Outcome in Heart Failure with Preserved Ejection Fraction1457Cardiac MRI Under Percussive Ventilation: A New Promising Technique1644Histological Validation of Cardiac Magnetic Resonance for the Evaluation of Myocardial Fibrosis after Heart Transplantation in Children1493First Pass Perfusion Reserve Index in

Diagnostic Accuracy of Myocardial Magnetic Resonance Perfusion to Diagnose Ischemic Stenosis With Fractional Flow Reserve as Reference: Systematic Review and Meta-Analysis

ObjectivesThis paper systematically analyzed the performance of magnetic resonance (MR) perfusion to diagnose coronary artery disease (CAD) with fractional flow reserve (FFR) as the reference standard. BackgroundMyocardial MR perfusion has passed the stage of a research technique and has demonstrated the ability to detect functional or ischemic stenosis of coronary arteries. However, the evidence is limited to single-center studies and small sample sizes. MethodsWe searched PubMed and Embase databases for all published studies that evaluated the accuracy of MR perfusion to diagnose CAD versus FFR. We used an exact binomial rendition of the bivariate mixed-effects regression model with test type as a random-effects covariate to synthesize the available data. Based on Bayes’ theorem, the post-test probability was calculated to guide MR perfusion’s clinical utility. ResultsWe identified 14 studies evaluating 1,073 arteries and 650 patients. The pooled sensitivity and specificity were 0.90 (95% confidence interval [CI]: 0.86 to 0.93) and 0.87 (95% CI: 0.82 to 0.90) at the patient level and 0.89 (95% CI: 0.83 to 0.92) and 0.86 (95% CI: 0.77 to 0.92) at the artery and territory levels, respectively. The area under the summary receiver-operating characteristic at the patient level was 0.95 (95% CI: 0.92 to 0.96) and 0.93 (95% CI: 0.91 to 0.95) at the artery and territory levels, respectively. MR perfusion could increase the post-test probability of CAD >80% in patients with a pre-test probability of >37% and can decrease post-test probability of CAD <20% with a pre-test probability of <72%. ConclusionsWith FFR as the reference standard, the diagnostic ability of MR perfusion to detect ischemic CAD is high.

Current international guidelines for the investigation of patients with suspected coronary artery disease

Patients suspected of having coronary artery disease (CAD) who present with new onset chest pain can be investigated by numerous diagnostic modalities. National and international guidelines have been drawn up to assist cardiologists in selecting the most appropriate investigation(s). Here, we summarize and compare three current guidelines and discuss the differences between them. The UK National Institute for Health and Care Excellence (NICE) published its guidelines in 2010.1 The guidelines recommend that patients are categorized into ‘low’ or ‘high’ risk of CAD groups, depending on whether they have a cardiovascular risk factor (diabetes, smoking, and hyperlipidaemia). Patients are assigned a pre-test probability (PTP) score of having CAD based on risk category, age, gender, and typicality of chest pain. The guidance then suggests that patients with a PTP of 400), a functional imaging test or invasive coronary angiography (ICA) is recommended. Patients with an intermediate PTP of 30–60% are recommended to have a functional imaging test; i.e. myocardial perfusion scintigraphy (MPS), stress echocardiography, or stress cardiac magnetic resonance imaging. Patients with a high PTP of 61–90% are recommended to undergo ICA, and patients with a PTP of >90% are assumed to have CAD without requiring further testing to make the diagnosis. The assessment of prognosis and management of patients diagnosed …

A spatially-distributed computational model to quantify behaviour of contrast agents in MR perfusion imaging.

Contrast agent enhanced magnetic resonance (MR) perfusion imaging provides an early, non-invasive indication of defects in the coronary circulation. However, the large variation of contrast agent properties, physiological state and imaging protocols means that optimisation of image acquisition is difficult to achieve. This situation motivates the development of a computational framework that, in turn, enables the efficient mapping of this parameter space to provide valuable information for optimisation of perfusion imaging in the clinical context. For this purpose a single-compartment porous medium model of capillary blood flow is developed which is coupled with a scalar transport model, to characterise the behaviour of both blood-pool and freely-diffusive contrast agents characterised by their ability to diffuse through the capillary wall into the extra-cellular space. A parameter space study is performed on the nondimensionalised equations using a 2D model for both healthy and diseased myocardium, examining the sensitivity of system behaviour to Peclet number, Damköhler number (Da), diffusivity ratio and fluid porosity. Assuming a linear MR signal response model, sample concentration time series data are calculated, and the sensitivity of clinically-relevant properties of these signals to the model parameters is quantified. Both upslope and peak values display significant non-monotonic behaviour with regard to the Damköhler number, with these properties showing a high degree of sensitivity in the parameter range relevant to contrast agents currently in use. However, the results suggest that signal upslope is the more robust and discerning metric for perfusion quantification, in particular for correlating with perfusion defect size. Finally, the results were examined in the context of nonlinear signal response, flow quantification via Fermi deconvolution and perfusion reserve index, which demonstrated that there is no single best set of contrast agent parameters, instead the contrast agents should be tailored to the specific imaging protocol and post-processing method to be used.

Assessment of myocardial reactivity to controlled hypercapnia with free-breathing T2-prepared cardiac blood oxygen level-dependent MR imaging.

To examine whether controlled and tolerable levels of hypercapnia may be an alternative to adenosine, a routinely used coronary vasodilator, in healthy human subjects and animals. Human studies were approved by the institutional review board and were HIPAA compliant. Eighteen subjects had end-tidal partial pressure of carbon dioxide (PetCO2) increased by 10 mm Hg, and myocardial perfusion was monitored with myocardial blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging. Animal studies were approved by the institutional animal care and use committee. Anesthetized canines with (n = 7) and without (n = 7) induced stenosis of the left anterior descending artery (LAD) underwent vasodilator challenges with hypercapnia and adenosine. LAD coronary blood flow velocity and free-breathing myocardial BOLD MR responses were measured at each intervention. Appropriate statistical tests were performed to evaluate measured quantitative changes in all parameters of interest in response to changes in partial pressure of carbon dioxide. Changes in myocardial BOLD MR signal were equivalent to reported changes with adenosine (11.2% ± 10.6 [hypercapnia, 10 mm Hg] vs 12% ± 12.3 [adenosine]; P = .75). In intact canines, there was a sigmoidal relationship between BOLD MR response and PetCO2 with most of the response occurring over a 10 mm Hg span. BOLD MR (17% ± 14 [hypercapnia] vs 14% ± 24 [adenosine]; P = .80) and coronary blood flow velocity (21% ± 16 [hypercapnia] vs 26% ± 27 [adenosine]; P > .99) responses were similar to that of adenosine infusion. BOLD MR signal changes in canines with LAD stenosis during hypercapnia and adenosine infusion were not different (1% ± 4 [hypercapnia] vs 6% ± 4 [adenosine]; P = .12). Free-breathing T2-prepared myocardial BOLD MR imaging showed that hypercapnia of 10 mm Hg may provide a cardiac hyperemic stimulus similar to adenosine.

Myocardial dynamic contrast-enhanced Mr: vascular diseases and beyond.

Contrast-enhanced cardiac magnetic resonance imaging allows the evaluation of both myocardial perfusion and myocardial tissue characteristics. This paper reviews different microvascular and non-vascular conditions that can cause abnormal findings on contrast-enhanced myocardial magnetic resonance imaging. Knowledge of their characteristics can avoid misinterpretation and avoid inappropriate referral for further invasive imaging in patients suspected of myocardial vascular disease.

Quantitative myocardial perfusion analysis using multi-row detector CT in acute myocardial infarction

ObjectiveTo assess the feasibility of quantitative myocardial perfusion imaging (MPI) in acute myocardial infarction (AMI), using multi-row detector CT (MDCT) with a model-based deconvolution method.Design, setting, patients and interventionsFifteen normal...

5‐Fluorouracil—Induced Tako‐Tsubo—Like Syndrome

Tako-Tsubo cardiomyopathy (also known as apical ballooning syndrome) is a relatively new clinical entity characterized by reversible left ventricular dysfunction. Its clinical presentation and electrocardiographic findings are similar to acute myocardial infarction but without significant coronary artery disease. Cardiotoxicity is a major complication of various anticancer drugs; however, only a few cases of Tako-Tsubo cardiomyopathy associated with anticancer drugs, including 5-fluorouracil, have been reported. We describe a 48-year-old man who developed acute coronary syndrome, thought to be similar to Tako-Tsubo syndrome, after receiving a chemotherapy regimen consisting of 5-fluorouracil, oxaliplatin, and calcium folinate (FOLFOX protocol) for colic adenocarcinoma. Approximately 24 hours after receiving his first cycle of chemotherapy, the patient, who did not have a history of cardiovascular disease, developed chest pain, with abnormal electrocardiographic results and a mildly increased troponin T level. Coronary angiography did not show any significant coronary lesions. Echocardiography revealed marked left ventricular dysfunction (left ventricular ejection fraction [LVEF] 15%) with severe hypokinesia in all apical and median segments. The patient was stabilized with the introduction of an intraaortic balloon pump and pressor therapy. One month later, myocardial magnetic resonance imaging confirmed total recovery of left ventricular systolic function. Thus, the second chemotherapy cycle was administered at half the dose-intensity, along with ramipril and diltiazem. The chemotherapy regimen was well tolerated. Two weeks later, at the end of the third chemotherapy cycle, administered using the full-dose regimen, the patient experienced cardiac arrest, necessitating cardiopulmonary resuscitation. After transfer to the cardiology intensive care unit, acute heart failure recurred (LVEF 35%). Normal recovery of left ventricular function occurred a few days later. Chemotherapy was discontinued, and treatment with bisoprolol was started. Four months later, the patient remained completely asymptomatic of any cardiac manifestations. Use of the Naranjo adverse drug reaction probability scale indicated a probable relationship (score of 8) between the patient's development of acute coronary Tako-Tsubo-like syndrome and 5-fluorouracil. Clinicians should be aware of this potential adverse effect when monitoring patients receiving chemotherapy with 5-fluorouracil.

Abstract 4230: Comparison of Dobutamine-atropine Stress Echocardiography and Magnetic Resonance for Detection of Obstructive Coronary Artery Disease by Assessing Wall Motion and Myocardial Perfusion Abnormalities

Background: The analysis of wall motion abnormalities (WMA) with dobutamine stress echocardiography or magnetic resonance is an established method for the detection of myocardial ischemia. Contrast echocardiography has been demonstrated a useful technique for evaluating myocardial perfusion (MP). We test the hypothesis that combination of MP and WMA would improve the diagnosis of coronary artery diseasen (CAD). Objective: To compare the diagnostic accuracy of dobutamine stress real-time myocardial contrast echocardiography (RTMCE) and gadolinium-enhanced magnetic resonance imaging (G-MRI) for detecting CAD by analyzing left ventricular WMA and MP. Methods: We prospectively studied 46 patients (23 males, mean age 58±8 years) referred for coronary angiography, RTMCE and MRI within a maximum interval of two weeks. Protocol used in RTMCE and G-MRI was four-stage dobutamine protocol (10 – 40 mcg/kg/min), with injection of atropine as required to reach 85% of age-adjusted target heart rate. Patients underwent first dobutamine stress RTMCE and then G-MRI using the same doses of dobutamine and atropine. RTMCE was performed using low-mechanical index imaging combined with intravenous commercially available contrast agent (Definity, Bristol-Myers Squibb). Positivity for the stress test was defined as new or worsening WMA or reversible perfusion defects in &gt;2 contiguous segments. Quantitative coronary angiography (QCA) was performed in all patients. CAD was defined as the presence of lesion &gt;50 % in at least one coronary artery territory. Results: All patients tolerated well dobutamine stress. In five patients G-MRI was not performed (2 because of claustrofobia, 1 because patient did not fit in MRI, 2 because of extensive ischemia by dobutamine RTMCE). A total of 41 patients underwent dobutamine RTMCE, G-MRI and QCA. The sensitivity, specificity, and accuracy to detect CAD by dobutamine RTMCE were 74%, 89% and 80% for the analysis of wall motion, 83%, 89% and 85% for the analysis of MP and 65%, 83% and 73% for dobutamine stress G-MRI. C onclusion: RTMCE seems to have better performance for detecting angiographically significant CAD than G-MRI using dobutamine stress. The analysis of MP increases sensitivity to RTMCE without changing specificity.