Cardiac MRI-Update 2020

Camera-on-tip endoscope for in vivo cardiovascular diagnostics and surgical guidance

Cardiovascular imaging with camera-on-tip endoscopes has the potential to provide physiologically relevant data on the tissue state and device placement that can improve clinical outcomes. In this work, we review the unmet clinical need for image-based in vivo cardiovascular diagnostics and guidance for minimally invasive procedures. We present a 7 Fr camera-on-tip endoscope with fibre-coupled multispectral illumination that includes methods for imaging in a blood-filled field of view (FOV). We demonstrate that the endoscope can be navigated from the femoral artery to cardiac regions such as the left atrium and left ventricle in a porcine model, where in vivo images of the cardiac walls are recorded. We further show that physiologically relevant parameters such as heart rate and respiration can be extracted from the images and that changes to tissue state can be inferred from the imaging data. Finally, a methodology for merging the imaging data with diffuse reflection spectroscopy (DRS) recorded through the optical fibre is outlined.

Barriers to cardiovascular magnetic resonance imaging scan performance and reporting by cardiologists: a systematic literature review

Aims

Cardiovascular magnetic resonance (CMR) imaging plays a pivotal role in diagnosing and managing cardiovascular diseases. Its use has shown sustained growth over the past years. However, there is considerable variability in the use and reporting of CMR scans worldwide. This review provides synthesis of evidence on the barriers and challenges to performing CMR scans by cardiologists and gain insights into the variations in CMR scan practices across different countries.

Methods and results

We systematically reviewed the literature from 1 January 2003 up to 13 November 2023. We searched four databases (Ovid Medline, Embase, Web of Science, and Scopus) and hand-searched the references in the included articles, complemented by expert feedback. Articles were double screened against pre-defined inclusion and exclusion criteria. We conducted risk of bias using the JBI critical appraisal tool, and we analysed information using a narrative synthesis of results. We identified 14 857 articles, with 13 articles meeting the inclusion criteria. The key barriers were the limited availability of CMR scanners, resulting in extended waiting times, the high service cost, and limited training opportunities and the lack of a structured curriculum. The main practice variations identified were geographical disparities in CMR use. Worldwide, the majority of CMR training programmes are situated in radiology departments.

Conclusion

Barriers to CMR use by cardiologists range from access to scanners and prohibitive costs to disparities in familiarity with CMR technology. Geographic variations and heterogeneity in training programmes underscore the influence of systemic factors such as healthcare infrastructure, reimbursement policies, and unstandardized training curricula.

Recent Progress of Cardiac MRI for Nuclear Medicine Professionals

Recent technical innovation enables faster and more reliable cardiac magnetic resonance (CMR) imaging than before. Artificial intelligence is used in improving image resolution, fast scanning, and automated analysis of CMR. Fast CMR techniques such as compressed sensing technique enable fast cine, perfusion, and late gadolinium-enhanced imaging and improve patient throughput and widening CMR indications. CMR feature-tracking technique gives insight on diastolic function parameters of ventricles and atria with prognostic implications. Myocardial parametric mapping became to be included in the routine CMR protocol. CMR fingerprinting enables simultaneous quantification of myocardial T1 and T2. These parameters may give information on myocardial alteration in the preclinical stages in various myocardial diseases. Four-dimensional flow imaging shows hemodynamic characteristics in or through the cardiovascular structures visually and gives quantitative values of vortex, kinetic energy, and wall-shear stress. In conclusion, CMR is an essential modality in the diagnosis of various cardiovascular diseases, especially myocardial diseases. Recent progress in CMR techniques promotes more widespread use of CMR in clinical practice. This review summarizes recent updates in CMR technologies and clinical research.

Update on cardiac imaging: A critical analysis

Imaging is instrumental in diagnosing and directing the management of atherosclerosis. In 1958 the first diagnostic coronary angiography (CA) was performed, and since then further development has led to new methods such as coronary CT angiography (CTA), optical coherence tomography (OCT), positron tomography (PET), and intravascular ultrasound (IVUS). Currently, CA remains powerful for visualizing coronary arteries; however, recent studies show the benefits of using other non-invasive techniques. This review identifies optimum imaging techniques for diagnosing and monitoring plaque stability. This becomes even direr now, given the rapidly rising incidence of atherosclerosis in society today. Many acute coronary events, including acute myocardial infarctions and sudden deaths, are attributable to plaque rupture. Although fatal, these events can be preventable. We discuss the factors affecting plaque integrity, such as increased inflammation, medications like statins, and increased lipid content. Some of these precipitating factors are identifiable through imaging. However, we also highlight significant complications arising in some modalities; in CA this can include ventricular arrhythmia and even death. Extending this, we elucidated from the literature that risk can also vary based on the location of arteries and their plaques. Promisingly, there are less invasive methods being trialled for assessing plaque stability, such as Cardiac Magnetic Resonance Imaging (CMR), which is already in use for other cardiac diseases like cardiomyopathies. Therefore, future research focusing on using imaging modalities in conjunction may be sensible, to bridge between the effectiveness of modalities, at the expense of increased complications, and vice versa.

Cardiac magnetic resonance imaging in systemic sclerosis: Heart involvement in high-resolution

Cardiac magnetic resonance imaging (CMR) is the gold-standard non-invasive method of assessing cardiac structure and function, including tissue characterisation. In systemic sclerosis (SSc), heart involvement (SHI) is a leading cause of mortality yet remains poorly understood. SHI is underestimated by conventional echocardiography, and CMR provides an important opportunity to better identify and quantify subtle myocardial changes including oedema and fibrosis. This review summarises current CMR techniques, the role of CMR in SSc and SHI, and the opportunities to further our understanding of its pathogenesis and management.

Intra-bin correction and inter-bin compensation of respiratory motion in free-running five-dimensional whole-heart magnetic resonance imaging

BACKGROUND

Free-running cardiac and respiratory motion-resolved whole-heart five-dimensional (5D) cardiovascular magnetic resonance (CMR) can reduce scan planning and provide a means of evaluating respiratory-driven changes in clinical parameters of interest. However, respiratory-resolved imaging can be limited by user-defined parameters which create trade-offs between residual artifact and motion blur. In this work, we develop and validate strategies for both correction of intra-bin and compensation of inter-bin respiratory motion to improve the quality of 5D CMR.

METHODS

Each component of the reconstruction framework was systematically validated and compared to the previously established 5D approach using simulated free-running data (N = 50) and a cohort of 32 patients with congenital heart disease. The impact of intra-bin respiratory motion correction was evaluated in terms of image sharpness while inter-bin respiratory motion compensation was evaluated in terms of reconstruction error, compression of respiratory motion, and image sharpness. The full reconstruction framework (intra-acquisition correction and inter-acquisition compensation of respiratory motion [IIMC] 5D) was evaluated in terms of image sharpness and scoring of image quality by expert reviewers.

RESULTS

Intra-bin motion correction provides significantly (p < 0.001) sharper images for both simulated and patient data. Inter-bin motion compensation results in significant (p < 0.001) lower reconstruction error, lower motion compression, and higher sharpness in both simulated (10/11) and patient (9/11) data. The combined framework resulted in significantly (p < 0.001) sharper IIMC 5D reconstructions (End-expiration (End-Exp): 0.45 ± 0.09, End-inspiration (End-Ins): 0.46 ± 0.10) relative to the previously established 5D implementation (End-Exp: 0.43 ± 0.08, End-Ins: 0.39 ± 0.09). Similarly, image scoring by three expert reviewers was significantly (p < 0.001) higher using IIMC 5D (End-Exp: 3.39 ± 0.44, End-Ins: 3.32 ± 0.45) relative to 5D images (End-Exp: 3.02 ± 0.54, End-Ins: 2.45 ± 0.52).

CONCLUSION

The proposed IIMC reconstruction significantly improves the quality of 5D whole-heart MRI. This may be exploited for higher resolution or abbreviated scanning. Further investigation of the diagnostic impact of this framework and comparison to gold standards is needed to understand its full clinical utility, including exploration of respiratory-driven changes in physiological measurements of interest.

Cardiac MRI: An Overview of Physical Principles With Highlights of Clinical Applications and Technological Advancements

The purpose of this review is to serve as a concise learning tool for clinicians interested in quickly learning more about cardiac magnetic resonance imaging (CMR) and its physical principles. There is heavy coverage of the basic physical fundamentals of CMR as well as updates on the history, clinical indications, cost-effectiveness, role of artificial intelligence in CMR, and examples of common late gadolinium enhancement (LGE) patterns. This literature review was performed by searching the PubMed database for the most up-to-date literature regarding these topics. Relevant, less up-to-date articles, covering the history and physics of CMR, were also obtained from the PubMed database. Clinical indications for CMR include adult congenital heart disease, cardiac ischemia, cardiomyopathies, and heart failure. CMR has a projected cost-benefit ratio of 0.58, leading to potential savings for patients. Despite its utility, CMR has some drawbacks including long image processing times, large space requirements for equipment, and patient discomfort during imaging. Artificial intelligence-based algorithms can address some of these drawbacks by decreasing image processing times and may have reliable diagnostic capabilities. CMR is quickly rising as a high-resolution, non-invasive cardiac imaging modality with an increasing number of clinical indications. Thanks to technological advancements, especially in artificial intelligence, the benefits of CMR often outweigh its drawbacks.

Cardiovascular risk assessment in inflammatory bowel disease with coronary calcium score

The interplay between inflammatory bowel disease (IBD) and atherosclerotic cardiovascular disease (ASCVD) underscores the intricate connections between chronic inflammation and cardiovascular health. This review explores the multifaceted relationship between these conditions, highlighting the emerging significance of the coronary calcium score as a pivotal tool in risk assessment and management. Chronic inflammation, a hallmark of IBD, has far-reaching systemic effects that extend to the cardiovascular system. Shared risk factors and mechanisms, such as endothelial dysfunction, lipid dysfunction, and microbiome dysregulation, contribute to the elevated ASCVD risk observed in individuals with IBD. Amidst this landscape, the coronary calcium score emerges as a means to quantify calcified plaque within coronary arteries, offering insights into atherosclerotic burden and potential risk stratification. The integration of the coronary calcium score refines cardiovascular risk assessment, enabling tailored preventive strategies for individuals with IBD. By identifying those at elevated risk, healthcare providers can guide interventions, fostering informed shared decision-making. Research gaps persist, prompting further investigation into mechanisms linking IBD and ASCVD, particularly in the context of intermediate mechanisms and early atherosclerotic changes. The potential of the coronary calcium score extends beyond risk assessment-it holds promise for targeted interventions. Randomized trials exploring the impact of IBD-modifying therapies on ASCVD risk reduction can revolutionize preventive strategies. As precision medicine gains prominence, the coronary calcium score becomes a beacon of insight, illuminating the path toward personalized cardiovascular care for individuals living with IBD. Through interdisciplinary collaboration and rigorous research, we embark on a journey to transform the paradigm of preventive medicine and enhance the well-being of this patient population.

Cardiac Magnetic Resonance Imaging Findings in Patients With Chronic Kidney Disease and End-Stage Kidney Disease: A Systematic Review and Meta-Analysis

In this systematic review and meta-analysis, we explored the utilization of cardiac magnetic resonance imaging (CMR) to detect fibrotic changes secondary to uremic cardiomyopathy during the early stages of chronic kidney disease (CKD) and in patients with end-stage kidney disease (ESKD). Uremic myocardial fibrosis can lead to arrhythmia and heart failure, and it is important to detect these changes. CMR offers a noninvasive way to characterize the severity of cardiac remodeling. A comprehensive search of multiple electronic databases was conducted. Studies were divided according to scanner field strength (1.5 or 3 Tesla). The random effects model was used to calculate the pooled mean, 95% confidence interval (CI), standard error, and standardized mean difference (SMD). The I2 statistic was used to assess the heterogeneity between study-specific estimates. The search retrieved 779 studies. From these, 20 studies met the inclusion criteria and had 642 CKD patients (mean age of 56.8 years; 65.2% males; mean estimated glomerular filtration rate (eGFR) of 33 mL/min/1.73 m2) and 658 ESKD patients on dialysis (mean age of 55.6 years; 63.3% males; mean dialysis duration of 3.47 years). CKD patients had an increased left ventricular mass index (LVMi) compared to controls, with an SMD of 0.37 (95% CI: 0.20-0.54; I2 0%; p-value <0.05). ESKD patients also had increased LVMi compared to controls, SMD 0.88 (95% CI: 0.35-1.41; I2 79.1%; p-value 0.001). Myocardial fibrosis assessment using T1 mapping showed elevated values; the SMD of native septal T1 values between CKD and controls was 1.099 (95% CI: 0.73-1.46; I2 33.6%; p-value <0.05), and the SMD of native septal T1 values between ESKD patients and controls was 1.12 (95% CI: 0.85-1.38; I2 33.69%; p-value <0.05). In conclusion, patients with CKD and ESKD with preserved left ventricular ejection fraction (LVEF) have higher LVMi and T1 values, indicating increased mass and fibrosis. T1 mapping can be used for the early detection of cardiomyopathy and as a risk stratification tool. Large, randomized trials are needed to confirm these findings and determine the effect of long-term dialysis on cardiac fibrosis.

Cardiac Involvement in LAMA2-Related Muscular Dystrophy and SELENON-Related Congenital Myopathy: A Case Series

Background

LAMA2-related muscular dystrophy (LAMA2-MD) and SELENON-related myopathy (SELENON-RM) are two rare neuromuscular diseases characterized by proximal and axial muscle weakness, scoliosis, spinal rigidity, low bone quality and respiratory impairment. Cardiac involvement has previously been described in retrospective studies and case reports, but large case series and prospective studies in unselected cohorts are lacking.

Objective

The objective of this study is to conduct prevalence estimations, perform cardiac phenotyping, and provide recommendations for clinical care.

Methods

In this case series including two time points, we conducted comprehensive assessments with electrocardiography (ECG) and transthoracic echocardiography (TTE). ECGs were systematically assessed for a large subset of variables. TTE included left and right ventricular ejection fraction (LVEF/RVEF) and left ventricular global longitudinal strain (GLS), the latter being a more early and sensitive marker of left ventricular dysfunction.

Results

21 LAMA2-MD (M = 5; 20±14 years) and 10 SELENON-RM patients (M = 7; 18±12 years) were included. In most patients, QRS fragmentation and Q waves, markers of heterogeneous ventricular activation, were present both at baseline and at follow-up. GLS was abnormal (age specific in children, > -18% in adults) in 33% of LAMA2-MD and 43% of SELENON-RM patients at baseline. Reduced LVEF (<52% in males, <54% in females and <55% in pediatric population) was observed in three LAMA2-MD patients at baseline and in none of the SELENON-RM patients. GLS and LVEF did not change between baseline and follow-up. RVEF was normal in all patients.

Conclusion

ECG abnormalities and abnormal GLS are prevalent in LAMA2-MD and SELENON-RM, yet abnormal LVEF was only seen in LAMA2-MD patients. One LAMA2-MD patient had a clinically relevant deterioration in LVEF during 1.5-year follow-up. We advise routine screening of all patients with LAMA2-MD or SELENON-RM with ECG and echocardiography at diagnosis, minimally every two years from second decade of life and if new cardiac signs arise.

Diagnostic accuracy of coronary artery stenosis and thrombosis assessment using unenhanced multiplanar 3D post-mortem cardiac magnetic resonance imaging

BACKGROUND

A 3D sequence was introduced to unenhanced post-mortem cardiac magnetic resonance imaging (PMCMR) to enable multiplanar coronary artery image analysis and to investigate its diagnostic accuracy for the diagnosis of coronary artery stenosis and thrombosis.

MATERIALS AND METHODS

N = 200 forensic cases with suspected coronary artery pathology underwent 3 Tesla PMCMR (sequence used: T2 weighted transversal 3D turbo spin echo) before autopsy. Main coronary artery stenosis and thrombosis were assessed in PMCMR by multiplanar image analysis by two observers. Coronary artery histology was determined as the gold standard and compared to PMCMR. Sensitivity, specificity, negative (NPV) and positive predictive values (PPV) with 95% confidence intervals were calculated.

RESULTS

For all coronary arteries combined, sensitivity was 75% (PPV 73%) for the diagnosis of stenosis and 72% (PPV 71%) for the diagnosis of thrombosis. Specificity was 92% (NPV 90%) for correct diagnosis of non-existing stenosis and 97% (NPV 97%) for non-existing thrombosis. Sensitivity for correct diagnosis of different degrees of stenosis ranged between 67% and 80% (PPVs 67-82%); specificity ranged between 96% and 99% (NPVs 96-99%).

CONCLUSION

Multiplanar PMCMR coronary artery stenosis and thrombosis assessment based on an unenhanced T2 weighted 3D sequence provide moderate sensitivity and high specificity for the diagnosis of coronary artery stenosis and/or thrombosis. Hence, 3D T2w PMCMR cannot reliably detect existing coronary artery stenosis and thrombosis but may be particularly useful for the exclusion of stenosis or thrombosis of the main coronary arteries.

Cardiac MRI-Based Assessment of Myocardial Injury in Asymptomatic People Living With Human Immunodeficiency Virus: Correlation With nadir CD4 Count

BACKGROUND

There are known cardiac manifestations of HIV, but the findings in asymptomatic subjects are still not fully explored.

PURPOSE

To evaluate for the presence of subclinical myocardial injury in asymptomatic people living with human immunodeficiency virus (PLWH) by cardiac MRI and to explore the possible association between subclinical myocardial injury and HIV-related clinical characteristics.

STUDY TYPE

Cross-sectional.

POPULATION

A total of 80 asymptomatic PLWH (age: 53 years [47-56 years]; 90% male) and 50 age- and sex-matched healthy participants.

FIELD STRENGTH/SEQUENCE

A 3-T, cine sequence, T1, T2, and T2* mapping.

ASSESSMENT

Function analysis was derived from short axis, two-, three-, and four-chamber cine images by feature tracking. Regions of interest were manually selected in the midventricular septum T1, T2, and T2* mapping sequences. PLWH were evaluated for T1 increment (△T1 mapping = native T1 - cutoff values) and HIV-related clinical characteristics, particularly the nadir CD4 count. And PLWH were stratified into two groups according to the cutoff value of native T1: elevated native T1 and normal.

STATISTICAL TESTS

T test, Wilcoxon rank-sum test, Chi-square test, Spearman rank correlation, and logistic regression. P <0.05 indicated statistical significance.

RESULTS

Asymptomatic PLWH revealed significantly higher native myocardial T1 values (1241 ± 29 msec vs. 1189 ± 21 msec), T2 values (40.7 ± 1.5 msec vs. 37.9 ± 1.4 msec), and lower LVGRS (30.2% ± 6.2% vs. 35.8% ± 6.4%), LVGCS (-18.0% ± 2.5% vs. -19.5% ± 2.0%), and LVGLS (-16.0% ± 3.8% vs. -17.9% ± 2.6%) but showed no difference in T2* values (17.3 msec [16.3-19.1 msec] vs. 18.3 msec [16.5-19.3 msec], P = 0.201). A negative correlation between the native T1 increment in PLWH with subclinical myocardial injury and the nadir CD4 count (u = -0.316). Nadir CD4 count <500 cells/mm3 was associated with higher odds of elevated native T1 myocardial values (odds ratio, 6.12 [95% CI, 1.07-34.91]) in PLWH.

DATA CONCLUSION

Subclinical myocardial inflammation and dysfunction were present in asymptomatic PLWH, and a lower nadir CD4 count may be a risk factor for subclinical myocardial injury.

EVIDENCE LEVEL

1.

TECHNICAL EFFICACY

Stage 2.

Development of an Expert-Level Right Ventricular Abnormality Detection Algorithm Based on Deep Learning

PURPOSE

Studies relating to the right ventricle (RV) are inadequate, and specific diagnostic algorithms still need to be improved. This essay is designed to make exploration and verification on an algorithm of deep learning based on imaging and clinical data to detect RV abnormalities.

METHODS

The Automated Cardiac Diagnosis Challenge dataset includes 20 subjects with RV abnormalities (an RV cavity volume which is higher than 110 mL/m2 or RV ejection fraction which is lower than 40%) and 20 normal subjects who suffered from both cardiac MRI. The subjects were separated into training and validation sets in a ratio of 7:3 and were modeled by utilizing a nerve net of deep-learning and six machine-learning algorithms. Eight MRI specialists from multiple centers independently determined whether each subject in the validation group had RV abnormalities. Model performance was evaluated based on the AUC, accuracy, recall, sensitivity and specificity. Furthermore, a preliminary assessment of patient disease risk was performed based on clinical information using a nomogram.

RESULTS

The deep-learning neural network outperformed the other six machine-learning algorithms, with an AUC value of 1 (95% confidence interval: 1-1) on both training group and validation group. This algorithm surpassed most human experts (87.5%). In addition, the nomogram model could evaluate a population with a disease risk of 0.2-0.8.

CONCLUSIONS

A deep-learning algorithm could effectively identify patients with RV abnormalities. This AI algorithm developed specifically for right ventricular abnormalities will improve the detection of right ventricular abnormalities at all levels of care units and facilitate the timely diagnosis and treatment of related diseases. In addition, this study is the first to validate the algorithm's ability to classify RV abnormalities by comparing it with human experts.

Epicardial Adipose Tissue: A Piece of The Puzzle in Pediatric Hypertension

Background and purpose: Epicardial adipose tissue (EAT) is a metabolically active tissue located on the surface of the myocardium, which might have a potential impact on cardiac function and morphology. The aim of this study was to evaluate whether EAT is associated with essential arterial hypertension (AH) in children and adolescents. Methods: Prospective cardiovascular magnetic resonance (CMR) study and clinical evaluation were performed on 72 children, 36 of whom were diagnosed with essential AH, and the other 36 were healthy controls. The two groups were compared in volume and thickness of EAT, end-diastolic volume, end-systolic volume, stroke volume, left ventricular (LV) ejection fraction, average heart mass, average LV myocardial thickness, peak filling rate, peak filling time and clinical parameters. Results: Hypertensive patients have a higher volume (16.5 ± 1.9 cm3 and 10.9 ± 1.5 cm3 (t = −13.815, p < 0.001)) and thickness (0.8 ± 0.3 cm and 0.4 ± 0.1 cm, (U = 65.5, p < 0.001)) of EAT compared to their healthy peers. The volume of EAT might be a potential predictor of AH in children. Conclusions: Our study indicates that the volume of EAT is closely associated with hypertension in children and adolescents.

Application of deep learning-based super-resolution to T1-weighted postcontrast gradient echo imaging of the chest

OBJECTIVES

A deep learning-based super-resolution for postcontrast volume-interpolated breath-hold examination (VIBE) of the chest was investigated in this study. Aim was to improve image quality, noise, artifacts and diagnostic confidence without change of acquisition parameters.

MATERIALS AND METHODS

Fifty patients who received VIBE postcontrast imaging of the chest at 1.5 T were included in this retrospective study. After acquisition of the standard VIBE (VIBES), a novel deep learning-based algorithm and a denoising algorithm were applied, resulting in enhanced images (VIBEDL). Two radiologists qualitatively evaluated both datasets independently, rating sharpness of soft tissue, vessels, bronchial structures, lymph nodes, artifacts, cardiac motion artifacts, noise levels and overall diagnostic confidence, using a Likert scale ranging from 1 to 4. In the presence of lung lesions, the largest lesion was rated regarding sharpness and diagnostic confidence using the same Likert scale as mentioned above. Additionally, the largest diameter of the lesion was measured.

RESULTS

The sharpness of soft tissue, vessels, bronchial structures and lymph nodes as well as the diagnostic confidence, the extent of artifacts, the extent of cardiac motion artifacts and noise levels were rated superior in VIBEDL (all P < 0.001). There was no significant difference in the diameter or the localization of the largest lung lesion in VIBEDL compared to VIBES. Lesion sharpness as well as detectability was rated significantly better by both readers with VIBEDL (both P < 0.001).

CONCLUSION

The application of a novel deep learning-based super-resolution approach in T1-weighted VIBE postcontrast imaging resulted in an improvement in image quality, noise levels and diagnostic confidence as well as in a shortened acquisition time.

Application of postmortem MRI for identification of medulla oblongata contusion as a cause of death: a case report

Whiplash injury is common in traffic accidents, and severe whiplash is characterized by cervical spinal cord injuries with cervical dislocation or fracture, that can be diagnosed by postmortem computed tomography (PMCT), postmortem magnetic resonance (PMMR), or conventional autopsy. However, for cervical spinal cord injury without fracture and dislocation, PMMR can be more informative because it provides higher resolution of soft tissues. We report the case of a 29-year-old male who died immediately following a traffic accident, in which the vehicle hit an obstacle at a high speed, causing deformation of the bumper and severe damage of the vehicle body. PMCT indicated no significant injuries or diseases related to death, but PMMR showed patchy abnormal signals in the medulla oblongata, and the lower edge of the cerebellar tonsil was herniated out of the foramen magnum. The subsequent pathological and histological results confirmed that death was caused by medulla oblongata contusion combined with cerebellar tonsillar herniation. Our description of this case of a rare but fatal whiplash injury in which there was no fracture or dislocation provides a better understanding of the potentially fatal consequences of cervical spinal cord whiplash injury without fracture or dislocation and of the underlying lethal mechanisms. Compared with PMCT, PMMR provides important diagnostic information in forensic practice for the identification of soft tissue injuries, and is therefore an important imaging modality for diagnosis of whiplash injury when there is no fracture or dislocation.

Chagas Heart Disease: Beyond a Single Complication, from Asymptomatic Disease to Heart Failure

Chagas cardiomyopathy (CC), caused by the protozoan Trypanosoma cruzi, is an important cause of cardiovascular morbidity and mortality in developing countries. It is estimated that 6 to 7 million people worldwide are infected, and it is predicted that it will be responsible for 200,000 deaths by 2025. The World Health Organization (WHO) considers Chagas disease (CD) as a Neglected Tropical Disease (NTD), which must be acknowledged and detected in time, as it remains a clinical and diagnostic challenge in both endemic and non-endemic regions and at different levels of care. The literature on CC was analyzed by searching different databases (Medline, Cochrane Central, EMBASE, PubMed, Google Scholar, EBSCO) from 1968 until October 2022. Multicenter and bioinformatics trials, systematic and bibliographic reviews, international guidelines, and clinical cases were included. The reference lists of the included papers were checked. No linguistic restrictions or study designs were applied. This review is intended to address the current incidence and prevalence of CD and to identify the main pathogenic mechanisms, clinical presentation, and diagnosis of CC.

Ferumoxytol-Enhanced Cardiac Magnetic Resonance Angiography and 4D Flow: Safety and Utility in Pediatric and Adult Congenital Heart Disease

Cardiac magnetic resonance imaging and angiography have a crucial role in the diagnostic evaluation and follow up of pediatric and adult patients with congenital heart disease. Although much of the information required of advanced imaging studies can be provided by standard gadolinium-enhanced magnetic resonance imaging, the limitations of precise bolus timing, long scan duration, complex imaging protocols, and the need to image small structures limit more widespread use of this modality. Recent experience with off-label diagnostic use of ferumoxytol has helped to mitigate some of these barriers. Approved by the U.S. FDA for intravenous treatment of anemia, ferumoxytol is an ultrasmall superparamagnetic iron oxide nanoparticle that has a long blood pool residence time and high relaxivity. Once metabolized by macrophages, the iron core is incorporated into the reticuloendothelial system. In this work, we aim to summarize the evolution of ferumoxytol-enhanced cardiovascular magnetic resonance imaging and angiography and highlight its many applications for congenital heart disease.

The Merits, Limitations, and Future Directions of Cost-Effectiveness Analysis in Cardiac MRI with a Focus on Coronary Artery Disease: A Literature Review

Cardiac magnetic resonance (CMR) imaging has a wide range of clinical applications with a high degree of accuracy for many myocardial pathologies. Recent literature has shown great utility of CMR in diagnosing many diseases, often changing the course of treatment. Despite this, it is often underutilized possibly due to perceived costs, limiting patient factors and comfort, and longer examination periods compared to other imaging modalities. In this regard, we conducted a literature review using keywords “Cost-Effectiveness” and “Cardiac MRI” and selected articles from the PubMed MEDLINE database that met our inclusion and exclusion criteria to examine the cost-effectiveness of CMR. Our search result yielded 17 articles included in our review. We found that CMR can be cost-effective in quality-adjusted life years (QALYs) in select patient populations with various cardiac pathologies. Specifically, the use of CMR in coronary artery disease (CAD) patients with a pretest probability below a certain threshold may be more cost-effective compared to patients with a higher pretest probability, although its use can be limited based on geographic location, professional society guidelines, and differing reimbursement patterns. In addition, a stepwise combination of different imaging modalities, with conjunction of AHA/ACC guidelines can further enhance the cost-effectiveness of CMR.

A Systematic Quality Scoring Analysis to Assess Automated Cardiovascular Magnetic Resonance Segmentation Algorithms

Background

The quantitative measures used to assess the performance of automated methods often do not reflect the clinical acceptability of contouring. A quality-based assessment of automated cardiac magnetic resonance (CMR) segmentation more relevant to clinical practice is therefore needed.

Objective

We propose a new method for assessing the quality of machine learning (ML) outputs. We evaluate the clinical utility of the proposed method as it is employed to systematically analyse the quality of an automated contouring algorithm.

Methods

A dataset of short-axis (SAX) cine CMR images from a clinically heterogeneous population (n = 217) were manually contoured by a team of experienced investigators. On the same images we derived automated contours using a ML algorithm. A contour quality scoring application randomly presented manual and automated contours to four blinded clinicians, who were asked to assign a quality score from a predefined rubric. Firstly, we analyzed the distribution of quality scores between the two contouring methods across all clinicians. Secondly, we analyzed the interobserver reliability between the raters. Finally, we examined whether there was a variation in scores based on the type of contour, SAX slice level, and underlying disease.

Results

The overall distribution of scores between the two methods was significantly different, with automated contours scoring better than the manual (OR (95% CI) = 1.17 (1.07–1.28), p = 0.001; n = 9401). There was substantial scoring agreement between raters for each contouring method independently, albeit it was significantly better for automated segmentation (automated: AC2 = 0.940, 95% CI, 0.937–0.943 vs manual: AC2 = 0.934, 95% CI, 0.931–0.937; p = 0.006). Next, the analysis of quality scores based on different factors was performed. Our approach helped identify trends patterns of lower segmentation quality as observed for left ventricle epicardial and basal contours with both methods. Similarly, significant differences in quality between the two methods were also found in dilated cardiomyopathy and hypertension.

Conclusions

Our results confirm the ability of our systematic scoring analysis to determine the clinical acceptability of automated contours. This approach focused on the contours' clinical utility could ultimately improve clinicians' confidence in artificial intelligence and its acceptability in the clinical workflow.

Role of cardiac magnetic resonance imaging in the diagnosis and management of COVID-19 related myocarditis: Clinical and imaging considerations

There is a growing evidence of cardiovascular complications in coronavirus disease 2019 (COVID-19) patients. As evidence accumulated of COVID-19 mediated inflammatory effects on the myocardium, substantial attention has been directed towards cardiovascular imaging modalities that facilitate this diagnosis. Cardiac magnetic resonance imaging (CMRI) is the gold standard for the detection of structural and functional myocardial alterations and its role in identifying patients with COVID-19 mediated cardiac injury is growing. Despite its utility in the diagnosis of myocardial injury in this population, CMRI’s impact on patient management is still evolving. This review provides a framework for the use of CMRI in diagnosis and management of COVID-19 patients from the perspective of a cardiologist. We review the role of CMRI in the management of both the acutely and remotely COVID-19 infected patient. We discuss patient selection for this imaging modality; T1, T2, and late gadolinium enhancement imaging techniques; and previously described CMRI findings in other cardiomyopathies with potential implications in COVID-19 recovered patients.

Cardiac sequelae after coronavirus disease 2019 recovery: a systematic review

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been implicated in a wide spectrum of cardiac manifestations following the acute phase of the disease.

OBJECTIVES

To assess the range of cardiac sequelae after COVID-19 recovery.

DATA SOURCES

PubMed, Embase, Scopus (inception through 17 February 2021) and Google scholar (2019 through 17 February 2021).

STUDY ELIGIBILITY CRITERIA

Prospective and retrospective studies, case reports and case series.

PARTICIPANTS

Adult patients assessed for cardiac manifestations after COVID-19 recovery.

EXPOSURE

Severe acute respiratory syndrome coronavirus 2 infection diagnosed by PCR.

METHODS

Systematic review.

RESULTS

Thirty-five studies (fifteen prospective cohort, seven case reports, five cross-sectional, four case series, three retrospective cohort and one ambidirectional cohort) evaluating cardiac sequelae in 52 609 patients were included. Twenty-nine studies used objective cardiac assessments, mostly cardiac magnetic resonance imaging (CMR) in 16 studies, echocardiography in 15, electrocardiography (ECG) in 16 and cardiac biomarkers in 18. Most studies had a fair risk of bias. The median time from diagnosis/recovery to cardiac assessment was 48 days (1-180 days). Common short-term cardiac abnormalities (<3 months) included increased T1 (proportion: 30%), T2 (16%), pericardial effusion (15%) and late gadolinium enhancement (11%) on CMR, with symptoms such as chest pain (25%) and dyspnoea (36%). In the medium term (3-6 months), common changes included reduced left ventricular global longitudinal strain (30%) and late gadolinium enhancement (10%) on CMR, diastolic dysfunction (40%) on echocardiography and elevated N-terminal proB-type natriuretic peptide (18%). In addition, COVID-19 survivors had higher risk (risk ratio 3; 95% CI 2.7-3.2) of developing heart failure, arrythmias and myocardial infarction.

CONCLUSIONS

COVID-19 appears to be associated with persistent/de novo cardiac injury after recovery, particularly subclinical myocardial injury in the earlier phase and diastolic dysfunction later. Larger well-designed and controlled studies with baseline assessments are needed to better measure the extent of cardiac injury and its clinical impact.

Global and Regional Test-Retest Reproducibility of Native T1 and T2 Mapping in Cardiac Magnetic Resonance Imaging

BACKGROUND

Mapping of T1 and T2 relaxation times in cardiac MRI is an invaluable tool for the diagnosis and risk stratification of a wide spectrum of cardiac diseases.

PURPOSE

To investigate the global and regional reproducibility of native T1 and T2 mapping and to analyze the influence of demographic factors, physiological parameters, slice position, and myocardial regions on reproducibility.

STUDY TYPE

Prospective single-center cohort-study.

POPULATION

Fifty healthy volunteers (29 female, 21 male) with a mean age of 39.4 ± 13.7 years.

FIELD STRENGTH/SEQUENCE

Each volunteer was investigated twice at 1.5 T using a modified look-locker inversion-recovery (MOLLI) sequence (T1 mapping) and a T2-prepared steady-state free precession (SSFP) sequence (T2 mapping).

ASSESSMENT

Global T1 and T2 values were quantified for the entire left ventricle in three short-axis slices. Regional T1 and T2 values were measured for each myocardial segment and for myocardial segments grouped by slice position and anatomical region.

STATISTICAL TESTS

Test-retest reproducibility was assessed using intraclass correlation coefficient (ICC) and Bland-Altman statistics. A P value < 0.05 was considered statistically significant.

RESULTS

Reproducibility was good for global T1 values (ICC 0.88) and excellent for global T2 values (ICC 0.91). Reproducibility of T1 values was excellent (ICC 0.91) for midventricular slice and good for apical (ICC 0.86) and basal slice (ICC 0.81). Reproducibility of T1 mapping values was highest in the septum (ICC 0.90) compared to the anterior (0.81), lateral (0.86), and inferior (0.86) wall. For T2 mapping, reproducibility was good for all slice positions (ICC 0.86 for midventricular, 0.83 for basal, and 0.80 for apical slice). Reproducibility of T2 mapping was significantly lower for the inferior wall (ICC 0.58) than for septum (0.89), anterior (0.85), and lateral (0.87) wall.

DATA CONCLUSION

Native T1 and T2 mapping has good to excellent reproducibility with significant regional differences.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

[Cardiac magnetic resonance imaging : Trends and developments]

BACKGROUND

In its almost 25 years of clinical use, cardiac magnetic resonance imaging (CMR) has been developed for a wide range of indications due to the development of robust techniques and their comprehensive validation. CMR-based assessment of cardiac volumes and systolic ventricular function as well as the characterization of focal myocardial scars belongs today to standard cardiac imaging. More recently, the introduction of accelerated acquisition techniques, quantitative myocardial T1- and T2-mapping methods and 4‑dimensional (4D) flow measurements as well as new postprocessing techniques such as myocardial feature tracking have attracted attention.

METHODS

This review is based on a comprehensive literature search in the PubMed database on new CMR techniques and their clinical application.

RESULTS AND CONCLUSION

This article provides an overview of the latest technical developments in the field of CMR and their possible applications based on the most important clinical MR issues.