Cardiac MRI: technical basis

Higher hemoglobin levels are associated with impaired left ventricular global strains in metabolic syndrome: a 3.0 T CMR feature tracking study

BACKGROUND

Metabolic syndrome (MetS) is a known contributor to increased cardiovascular risk and all-cause mortality. Recent literatures suggested that higher hemoglobin (Hb) levels were associated with Mets, left ventricular (LV) dysfunction and adverse events in general population. This study aimed to assess the associations between Hb levels and LV global strains in patients with MetS.

METHODS

A retrospective analysis included 254 patients with MetS and 78 sex-, age-, and Hb-matched controls. The MetS patients were stratified into five groups based on Hb levels: anemia, low-normal Hb, moderate-normal Hb, high-normal Hb, and high Hb. LV global radial, circumferential, and longitudinal strains (LVGRS, LVGCS, and LVGLS, respectively) were measured using the cardiac magnetic resonance feature tracking technique. Associations between Hb levels and LV global strains were evaluated using multiple linear regression, restricted cubic spline (RCS), and subgroup analyses.

RESULTS

After full adjustment, the LV global strains from three directions in the high Hb groups (LVGRS: β = -  4.943, 95% CI -  7.673 to - 2.213; LVGCS: β = -  2.341, 95% CI - 3.608 to - 1.074; LVGLS: β = -2.797, 95% CI - 4.049 to - 1.546, all p < 0.05) were significantly reduced than those in their respective moderate-normal Hb groups. Full adjusted RCS plots revealed inverted L-shaped associations between Hb levels and LV global strains, with significant reductions observed above 143 g/L (all p for nonlinearity < 0.05). Subgroup analyses indicated that the associations were more pronounced in MetS patients with obesity (LVGRS: β = -  0.005 [95% CI - 0.087 to 0.097] versus -0.087 [95% CI - 0.145 to - 0.030]; LVGCS: β = -0.006 [95% CI - 0.045 to 0.034] versus -0.048 [95% CI - 0.075 to - 0.021]; LVGLS: β = -0.011 [95% CI -  0.053 to 0.032] versus -0.063 [95% CI - 0.089 to - 0.036] for non-obese and obese patients; all p for interaction < 0.05).

CONCLUSIONS

Higher Hb levels are significantly associated with more severe LV dysfunction in MetS patients, particularly in those with obesity. Targeted monitoring and management of higher Hb levels in MetS patients may help mitigate further deterioration of cardiac function.

Non-invasive Assessment of Coronary Artery Disease: The Role of AI in the Current Status and Future Directions

Coronary artery disease (CAD) remains a significant public health concern due to its high morbidity and mortality rates. Early detection and timely evaluation are crucial for improving patient outcomes. While both invasive and non-invasive methods are available for assessing CAD risk, non-invasive approaches minimize the complications associated with invasive procedures. Over the past two decades, advancements in artificial intelligence (AI), particularly machine learning techniques such as deep learning and natural language processing, have revolutionized cardiology. These technologies enhance diagnostic accuracy and clinical efficiency in non-invasive CAD evaluation. However, the broader adoption of AI faces critical challenges, including ethical concerns such as data privacy, high computational costs, and resource allocation disparities. This article explores the current landscape of non-invasive CAD assessment, highlighting the transformative potential and associated challenges of AI integration.

Deep Transfer Learning for Classification of Late Gadolinium Enhancement Cardiac MRI Images into Myocardial Infarction, Myocarditis, and Healthy Classes: Comparison with Subjective Visual Evaluation

Background/Objectives: To develop a computer-aided diagnosis (CAD) method for the classification of late gadolinium enhancement (LGE) cardiac MRI images into myocardial infarction (MI), myocarditis, and healthy classes using a fine-tuned VGG16 model hybridized with multi-layer perceptron (MLP) (VGG16-MLP) and assess our model's performance in comparison to various pre-trained base models and MRI readers. Methods: This study included 361 LGE images for MI, 222 for myocarditis, and 254 for the healthy class. The left ventricle was extracted automatically using a U-net segmentation model on LGE images. Fine-tuned VGG16 was performed for feature extraction. A spatial attention mechanism was implemented as a part of the neural network architecture. The MLP architecture was used for the classification. The evaluation metrics were calculated using a separate test set. To compare the VGG16 model's performance in feature extraction, various pre-trained base models were evaluated: VGG19, DenseNet121, DenseNet201, MobileNet, InceptionV3, and InceptionResNetV2. The Support Vector Machine (SVM) classifier was evaluated and compared to MLP for the classification task. The performance of the VGG16-MLP model was compared with a subjective visual analysis conducted by two blinded independent readers. Results: The VGG16-MLP model allowed high-performance differentiation between MI, myocarditis, and healthy LGE cardiac MRI images. It outperformed the other tested models with 96% accuracy, 97% precision, 96% sensitivity, and 96% F1-score. Our model surpassed the accuracy of Reader 1 by 27% and Reader 2 by 17%. Conclusions: Our study demonstrated that the VGG16-MLP model permits accurate classification of MI, myocarditis, and healthy LGE cardiac MRI images and could be considered a reliable computer-aided diagnosis approach specifically for radiologists with limited experience in cardiovascular imaging.

Advancements in Artificial Intelligence in Noninvasive Cardiac Imaging: A Comprehensive Review

BACKGROUND

Technological advancements in artificial intelligence (AI) are redefining cardiac imaging by providing advanced tools for analyzing complex health data. AI is increasingly applied across various imaging modalities, including echocardiography, magnetic resonance imaging (MRI), computed tomography (CT), and nuclear imaging, to enhance diagnostic workflows and improve patient outcomes.

HYPOTHESIS

Integrating AI into cardiac imaging enhances image quality, accelerates processing times, and improves diagnostic accuracy, enabling timely and personalized interventions that lead to better health outcomes.

METHODS

A comprehensive literature review was conducted to examine the impact of machine learning and deep learning algorithms on diagnostic accuracy, the detection of subtle patterns and anomalies, and key challenges such as data quality, patient safety, and regulatory barriers.

RESULTS

Findings indicate that AI integration in cardiac imaging enhances image quality, reduces processing times, and improves diagnostic precision, contributing to better clinical decision-making. Emerging machine learning techniques demonstrate the ability to identify subtle cardiac abnormalities that traditional methods may overlook. However, significant challenges persist, including data standardization, regulatory compliance, and patient safety concerns.

CONCLUSIONS

AI holds transformative potential in cardiac imaging, significantly advancing diagnosis and patient outcomes. Overcoming barriers to implementation will require ongoing collaboration among clinicians, researchers, and regulatory bodies. Further research is essential to ensure the safe, ethical, and effective integration of AI in cardiology, supporting its broader application to improve cardiovascular health.

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.

Prognostic value of enhanced cine cardiac MRI-based radiomics in dilated cardiomyopathy

BACKGROUND

Early precise identification of high-risk dilated cardiomyopathy (DCM) phenotype is essential for clinical decision-making and patient surveillance. The aim of the study was to assess the prognostic value of enhanced cine cardiac magnetic resonance (CMR)-based radiomics in DCM.

METHODS

We prospectively enrolled 401 (training set: 281; test set: 120) DCM patients. Radiomic features were extracted from enhanced cine images of entire left ventricular wall and selected by the least absolute shrinkage and selection operator. Different predictive models were built using logistic regression classifier to predict all-cause mortality and heart transplantation. Model performances were compared with the area under the receiver operating characteristic curves (AUCs). Kaplan-Meier curves, log-rank test, and Cox regression were used for survival analysis.

RESULTS

Endpoint events occurred in 65 patients over a median follow-up period of 25.4 months. 13 radiomic features were finally selected. The Rad_Combined model integrating clinical characteristics, CMR parameters and radiomics features achieved the best performance with an AUC of 0.836 and 0.835 in the training and test sets, respectively. High-risk groups with endpoint events defined by the Rad_Combined model had significantly shorter survival time than low-risk group in both the training [Hazard Ratio (HR) = 7.74, P < 0.001] and test sets (HR = 4.84, P < 0.001).

CONCLUSION

The Rad_Combined model might serve as an effective tool to help risk stratification and clinical decision-making for patients with DCM.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800017058 by the ethics committee of West China hospital,Sichuan University.

Changes in the Structure, Function, and Fat Content of the Heart in Patients with Obesity After Bariatric Surgery-A Prospective Magnetic Resonance Imaging Study

BACKGROUND

Changes in myocardial fat in addition to changes in cardiac structure and function have not been accurately evaluated in obese patients following surgery.

MATERIALS AND METHODS

Forty-four obese patients who underwent sleeve gastrectomy and completed preoperative and postoperative cardiac magnetic resonance imaging (CMR) before surgery and at 1, 3, and 6 months after surgery were enrolled, and their clinical and laboratory data were collected. The differences and correlations between clinical, laboratory, and CMR parameters between the preoperative and postoperative groups were analysed.

RESULTS

The left ventricular mass (LVM), left ventricle cardiac output (LVCO), pericardial adipose tissue volume (PATV), and myocardial proton density fat fraction (M-PDFF) decreased after surgery (all P < 0.05). The left ventricle global longitudinal strain increased at 6 months after surgery (P = 0.004). A decrease in BMI was positively correlated with the LVCO (r = 0.58, P < 0.001) at 3 months after surgery and was positively correlated with the LVM and PATV (r = 0.54, P < 0.05) at 6 months after surgery. Six months after surgery, the changes in PATV were positively correlated with the changes in triglycerides (r = 0.61, P < 0.01). There was a moderately positive correlation between the decrease in the LVM and PATV (r = 0.54 ~ 0.71, P < 0.02) after surgery.

CONCLUSION

After surgery, the cardiac structure and function of obese patients significantly improved, the PATV and M-PDFF decreased, and there was a correlation between the structure and function of the heart and several clinical and laboratory indicators.

Efficacy and safety of Qishen Yiqi dropping pills combined with modern medicine for coronary heart disease with ischemic heart failure: A systematic review and meta-analysis

BACKGROUND

Qishen Yiqi dropping pills combined with modern medicine have been widely used as a treatment for coronary heart disease with ischemic heart failure. Currently, there have been no robust studies addressing the efficacy and safety of Qishen Yiqi dropping pills combined with modern medicine for coronary heart disease with ischemic heart failure. Therefore, this systematic review and meta-analysis are conducted to fill in the gaps mentioned above.

METHODS

This systematic review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Relevant studies published from inception to April 17, 2023, in the 5 electronic databases: PubMed, The Cochrane Library, EMBASE, CNKI, and the Wanfang database were comprehensively searched. Weighted mean difference was used as the effect size for the continuous variables. Pooled odd ratios are presented if the results are binary variables. Additionally, we performed subgroup and sensitivity analyses to examine the source of heterogeneity. The funnel plot and the Egger test were used to estimate publication bias.

RESULTS

This meta-analysis included 46 studies involving 5843 participants. There is a significant difference in clinical efficacy, the 6-minute walk test (weighted mean difference = 50.10; 95% CI 28.19 to 72.02; I2 = 98.9%, P = .000), the indexes of ultrasonic cardiogram, blood biochemical indexes, and adverse effects (odds ratios = 0.46; 95% CI 0.29 to 0.75; I2 = 35.9%, P = .142). The sensitivity analysis and publication bias have demonstrated the robustness of the results (P = .702).

CONCLUSION

Qishen Yiqi dropping pills combined with modern medicine could significantly improve clinical efficacy without incasement adverse effects. Further studies are required to identify the more comprise efficacy and safety results.

Beyond genomic studies of congenital heart defects through systematic modelling and phenotyping

Congenital heart defects (CHDs), the most common congenital anomalies, are considered to have a significant genetic component. However, despite considerable efforts to identify pathogenic genes in patients with CHDs, few gene variants have been proven as causal. The complexity of the genetic architecture underlying human CHDs likely contributes to this poor genetic discovery rate. However, several other factors are likely to contribute. For example, the level of patient phenotyping required for clinical care may be insufficient for research studies focused on mechanistic discovery. Although several hundred mouse gene knockouts have been described with CHDs, these are generally not phenotyped and described in the same way as CHDs in patients, and thus are not readily comparable. Moreover, most patients with CHDs carry variants of uncertain significance of crucial cardiac genes, further complicating comparisons between humans and mouse mutants. In spite of major advances in cardiac developmental biology over the past 25 years, these advances have not been well communicated to geneticists and cardiologists. As a consequence, the latest data from developmental biology are not always used in the design and interpretation of studies aimed at discovering the genetic causes of CHDs. In this Special Article, while considering other in vitro and in vivo models, we create a coherent framework for accurately modelling and phenotyping human CHDs in mice, thereby enhancing the translation of genetic and genomic studies into the causes of CHDs in patients.

Impact of systemic lupus erythematosus on cardiovascular morphologic and functional phenotypes: a Mendelian randomization analysis

Background

Previous studies have established a correlation between systemic lupus erythematosus (SLE) and cardiovascular health, but the potential causal effects of SLE on heart function and structure remain poorly understood. Cardiovascular magnetic resonance imaging (CMR), a novel non-invasive technique, provides a unique assessment of cardiovascular structure and function, making it an essential tool for evaluating the risk of heart disease. In this study, we performed a Mendelian randomization analysis to determine the causal relationship between SLE and CMR traits.

Methods

Genetic variants independently linked to SLE were selected from a genome-wide association study (GWAS) containing 5,201 cases and 9,066 controls as instrumental variables. A set of 82 CMR traits was obtained from a recent GWAS, serving as preclinical indicators and providing preliminary insights into the morphology and function of the four cardiac chambers and two aortic segments. Primary analysis employed a two-sample Mendelian randomization study using the inverse-variance weighted method. Heterogeneity testing, sensitivity analyses, and instrumental variable strength assessments confirmed the robustness of the findings.

Results

SLE exhibited a correlation with increased stroke volume (βLVSV = 0.007, P = 0.045), regional peak circumferential strain (βEcc_AHA_9 = 0.013, P = 0.002; βEcc_AHA_12 = 0.009, P = 0.043; βEcc_AHA_14 = 0.013, P = 0.006), and global peak circumferential strain of the LV (βEcc_global = 0.010, P = 0.022), as well as decreased regional radial strain (βErr_AHA_11 = -0.010, P = 0.017).

Conclusions

This research presents evidence of a potential causal association between traits of SLE and alterations in cardiac function, guiding cardiac examinations and disease prevention in lupus patients.

Predictors of anxiety in patients undergoing magnetic resonance imaging scans: a multicenter cross-sectional study

BACKGROUND

Magnetic resonance imaging (MRI) is a noninvasive diagnostic tool that is commonly used to visualize soft tissues and anatomical structures. Many patients who undergo MRI scans experience anxiety. This multicenter study was conducted to assess anxiety levels experienced by patients who underwent MRI scans in the Palestinian radiology departments and identify the risk factors associated with higher levels of anxiety experienced by the patients.

METHODS

This multicenter cross-sectional study was conducted in the radiology departments of different hospitals in the West Bank of Palestine using a questionnaire. The questionnaire collected different demographic data of the patients. A 100-mm visual analog scale (VAS) was used to assess the level of anxiety experienced by the patients who received MRI scans. The data were analyzed using SPSS version 28.

RESULTS

A total of 383 patients participated in this study. Of the patients, 255 (66.6%) reported experiencing low, moderate, or high anxiety levels during the MRI scan. The median anxiety was 20.0 with an interquartile range (IQR) of 0.0-50.0 as measured using the 100-mm VAS. Higher anxiety levels were reported by the patients who were female (p-value < 0.001), unemployed (p-value = 0.009), and did not receive an MRI scan before (p-value = 0.001). In addition, the patients who received pelvis scans reported higher levels of anxiety compared to those who received scans for upper extremities (p-value = 0.031), abdomen (p-value = 0.033), pelvis (p-value = 0.043), and lower extremities (p-value = 0.016). In addition, the patients who received scans for the head/neck reported higher levels of anxiety compared to the patients who received scans for the lower extremities (p-value = 0.021).

CONCLUSION

The findings of this study showed that a considerable proportion of the patients who received MRI scans in Palestinian hospitals experience anxiety. Radiologists and other decision-makers in the healthcare system should design effective measures to reduce anxiety and improve the experiences of patients who are female, unemployed, and those who are scheduled to receive MRI scans for the first time. Moreover, these interventions should particularly focus on the patients who are scheduled to receive scans for the pelvis and head/neck.

Changes of cardiac function: cardiac adaptation in patients with hypothyroidism assessed by cardiac magnetic resonance-a meta-analysis

Objective

The meta-analysis aimed to explore the cardiac adaptation in hypothyroidism patients by cardiac magnetic resonance.

Research methods and procedures

Databases including PubMed, Cochrane Library, Embase, CNKI, and Sinomed for clinical studies of hypothyroidism on cardiac function changes. Databases were searched from the earliest data to 15 June 2023. Two authors retrieved studies and evaluated their quality. Review Manager 5.4.1 and Stata18 were used to analyze the data. This study is registered with the International Platform of Registered Systematic Review and Meta-analysis Protocols (INPLASY), 202440114.

Results

Six studies were selected for further analysis. Five of them reported differences in cardiac function measures between patients with hypothyroidism and healthy controls, and three studies reported cardiac function parameters after treatment in patients with hypothyroidism. The fixed-effect model combined WMD values for left ventricular ejection fraction (LVEF) had a pooled effect size of -1.98 (95% CI -3.50 to -0.44], P=0.01), implying that LVEF was lower in patients with hypothyroidism than in healthy people. Analysis of heterogeneity found moderate heterogeneity (P = 0.08, I² = 50%). WMD values for stroke volume (SV), cardiac index (CI), left ventricular end-diastolic volume index(LVEDVI), left ventricular end-systolic volume (LESVI), and left ventricular mass index(LVMI) were also analyzed, and pooled effect sizes showed the CI and LVEDVI of patients with hypothyroidism ware significantly decrease (WMD=-0.47, 95% CI [-0.93 to -0.00], P=0.05, WMD=-7.99, 95%CI [-14.01 to -1.96], P=0.009, respectively). Patients with hypothyroidism tended to recover cardiac function after treatment [LVEF (WMD = 6.37, 95%CI [2.05, 10.69], P=0.004), SV (WMD = 7.67, 95%CI [1.61, 13.74], P=0.01), CI (WMD = 0.40, 95%CI [0.01, 0.79], P=0.05)], and there was no difference from the healthy controls.

Conclusion

Hypothyroidism could affect cardiac function, although this does not cause significant heart failure. It may be an adaptation of the heart to the hypothyroid state. There was a risk that this adaptation may turn into myocardial damage. Cardiac function could be restored after treatment in patients with hypothyroidism. Aggressive levothyroxine replacement therapy should be used to reverse cardiac function.

Systematic review registration

https://inplasy.com, identifier (INPLASY202440114).

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.

Evaluation of the relationship between left atrial stiffness, left ventricular stiffness, and left atrioventricular coupling index in type 2 diabetes patients: a speckle tracking echocardiography study

BACKGROUND

Cardiovascular complications are a leading cause of mortality and disability in individuals with diabetes mellitus (DM). Moreover, DM can directly impact the structure and function of cardiac muscle. We conducted a study to evaluate cardiac stiffness in DM patients in both the left atrium (LA) and left ventricle (LV), as well as to assess the impact of DM on the synchronization of the LA and LV, particularly within the Vietnamese population, utilizing speckle tracking echocardiography (STE).

METHODS

We studied 111 research subjects divided into two groups comprising 52 patients with DM and 59 healthy individuals. All the subjects provided relevant clinical information, and echocardiography was performed to assess the indices of LA stiffness, LV stiffness, and left atrioventricular coupling index (LACI).

RESULTS

Our study indicated that DM patients exhibited greater LA and LV stiffness than control patients. The LACI (%) in the DM group was also greater than that in the control group (17.12% ± 6.72% vs. 12.28% ± 3.96%, respectively; p < 0.001). The LACI was positively correlated with the LA and LV stiffness indices. Decreased levels of LV GLS, adjusted for age, sex, blood pressure, and BMI, have emerged as identified risk factors for DM.

CONCLUSIONS

LA stiffness, LV stiffness, and the LACI are greater in DM patients than in normal individuals.

Developing and evaluating a chronic ischemic cardiomyopathy in swine model by rest and stress CMR

A large animal model of chronic coronary artery disease (CAD) is crucial for the understanding the underlying pathophysiological processes of chronic CAD and consequences for cardiac structure and function. The goal of this study was to develop a chronic model of CAD in a swine model and to evaluate the changes of myocardial structure, myocardial motility, and myocardial viability during coronary stenosis. A total of 30 swine (including 24 experimental animals and 6 controls) were enrolled. The chronic ischemia model was constructed by using Ameroid constrictor in experimental group. The 24 experimental animals were further divided into 4 groups (6 animals in each group) and were sacrificed at 1, 2, 3 and 4 weeks after operation for pathological examination, respectively. Cardiac magnetic resonance (CMR) was performed preoperatively and weekly postoperatively until sacrificed both in experimental and control group. CMR cine images, rest/adenosine triphosphate (ATP) stress myocardial contrast perfusion and LGE were performed and analyzed. The rest wall thickening (WT) score was calculated from rest cine images. The MPRI (myocardial perfusion reserve index) and MPR (myocardial perfusion reserve) were calculated based on rest and stress perfusion images. Pathology staining including triphenyltetrazolium chloride, HE and picrosirus red staining were performed after swine were sacrificed and collagen volume fraction (CVF) was calculated. The time to formation of ischemic, hibernating, and infarcted myocardium was recorded. In experimental group, from 1w to 4w after surgery, the rest WT score decreased gradually from 35.2 ± 2.0%, 32.0 ± 2.9% to 30.5 ± 3.0% and finally 29.06 ± 1.78%, p < 0.001. Left ventricular ejection fraction was gradually impaired after modeling (58.9 ± 12.6%, 56.3 ± 10.1%, 55.3 ± 9.0%, 53.8 ± 9.9%, respectively). And the MPR and MPRI also decreased stepwise with extent of surgery time (MPRI dropped from 2.1 ± 0.4, 2.0 ± 0.2 to 1.8 ± 0.3 and finally 1.7 ± 0.1, p = 0.004; MPR dropped from 2.3 ± 0.4, 2.1 ± 0.2 to 1.9 ± 0.4 and finally 1.8 ± 0.1, p < 0.001). Stronger associations between MPR, MPRI and CVF were paralleled lower wall thickening scores in fibrosis-affected areas. The ischemic myocardium was first appeared in the first week after surgery (involving ten segments), hibernated myocardium was first appeared in the second week after surgery (involving seventeen segments). LGE was first appeared in eight swine in the third weeks after surgery (16 segments). At 4w after surgery, average 9.6 g scar tissue was found among 6 swine. At the same time, histological analysis established the presence of fibrosis and ongoing apoptosis in the infarcted area. In conclusion, our study provided valuable insights into the pathophysiological processes of chronic CAD and its consequences for cardiac structure and function in a large animal model through combining myocardial motion and stress perfusion.

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.

Coronary Artery Fistula: A Diagnostic Dilemma

Coronary artery fistula (CAF), although one of the rare coronary anomalies, is becoming increasingly more detectable in the recent years due to advancements in cardiac diagnostic imaging. Its long-term prognostic implications and importance for the cardiovascular system remain a dilemma for cardiologists and patients. Based on a variety of haemodynamic symptoms and complications, cardiologists must be aware of the characteristics of CAF and the diagnostic importance of multi-slice CT in evaluation, pre-procedural management and follow-up. Both surgical and percutaneous options are available for symptomatic patients or those with complications, while management of asymptomatic CAF remains a viable alternative.

Three-Dimensional Bioprinting in Cardiovascular Disease: Current Status and Future Directions

Three-dimensional (3D) printing plays an important role in cardiovascular disease through the use of personalised models that replicate the normal anatomy and its pathology with high accuracy and reliability. While 3D printed heart and vascular models have been shown to improve medical education, preoperative planning and simulation of cardiac procedures, as well as to enhance communication with patients, 3D bioprinting represents a potential advancement of 3D printing technology by allowing the printing of cellular or biological components, functional tissues and organs that can be used in a variety of applications in cardiovascular disease. Recent advances in bioprinting technology have shown the ability to support vascularisation of large-scale constructs with enhanced biocompatibility and structural stability, thus creating opportunities to replace damaged tissues or organs. In this review, we provide an overview of the use of 3D bioprinting in cardiovascular disease with a focus on technologies and applications in cardiac tissues, vascular constructs and grafts, heart valves and myocardium. Limitations and future research directions are highlighted.

Radiomics applications in cardiac imaging: a comprehensive review

Radiomics is a new emerging field that includes extraction of metrics and quantification of so-called radiomic features from medical images. The growing importance of radiomics applied to oncology in improving diagnosis, cancer staging and grading, and improved personalized treatment, has been well established; yet, this new analysis technique has still few applications in cardiovascular imaging. Several studies have shown promising results describing how radiomics principles could improve the diagnostic accuracy of coronary computed tomography angiography (CCTA) and magnetic resonance imaging (MRI) in diagnosis, risk stratification, and follow-up of patients with coronary heart disease (CAD), ischemic heart disease (IHD), hypertrophic cardiomyopathy (HCM), hypertensive heart disease (HHD), and many other cardiovascular diseases. Such quantitative approach could be useful to overcome the main limitations of CCTA and MRI in the evaluation of cardiovascular diseases, such as readers' subjectiveness and lack of repeatability. Moreover, this new discipline could potentially overcome some technical problems, namely the need of contrast administration or invasive examinations. Despite such advantages, radiomics is still not applied in clinical routine, due to lack of standardized parameters acquisition, inconsistent radiomic methods, lack of external validation, and different knowledge and experience among the readers. The purpose of this manuscript is to provide a recent update on the status of radiomics clinical applications in cardiovascular imaging.

Imaging of metabolic and overload disorders in tissues and organs

Metabolic and overload disorders are a heterogeneous group of relatively uncommon but important diseases. While imaging plays a key role in the early detection and accurate diagnosis in specific organs with a pivotal role in several metabolic pathways, most of these diseases affect different tissues as part of a systemic syndromes. Moreover, since the symptoms are often vague and phenotypes similar, imaging alterations can present as incidental findings, which must be recognized and interpreted in the light of further biochemical and histological investigations. Among imaging modalities, MRI allows, thanks to its multiparametric properties, to obtain numerous information on tissue composition, but many metabolic and accumulation alterations require a multimodal evaluation, possibly using advanced imaging techniques and sequences, not only for the detection but also for accurate characterization and quantification. The purpose of this review is to describe the different alterations resulting from metabolic and overload pathologies in organs and tissues throughout the body, with particular reference to imaging findings.

Practical Guide to Interpreting Cardiac Magnetic Resonance in Patients with Cardiac Masses

It is common for a cardiac mass to be discovered accidentally during an echocardiographic examination. Following the relief of a cardiac mass, being able to evaluate and characterize it using non-invasive imaging methods is critical. Echocardiography, computed tomography (CT), cardiac magnetic resonance imaging (CMR), and positron emission tomography (PET) are the main imaging modalities used to evaluate cardiac masses. Although multimodal imaging often allows for a better assessment, CMR is the best technique for the non-invasive characterization of tissues, as the different MR sequences help in the diagnosis of cardiac masses. This article provides detailed descriptions of each CMR sequence employed in the evaluation of cardiac masses, underlining the potential information it can provide. The description in the individual sequences provides useful guidance to the radiologist in performing the examination.

Investigating the effect of oblique image acquisition on the accuracy of QSM and a robust tilt correction method

PURPOSE

Quantitative susceptibility mapping (QSM) is used increasingly for clinical research where oblique image acquisition is commonplace, but its effects on QSM accuracy are not well understood.

THEORY AND METHODS

The QSM processing pipeline involves defining the unit magnetic dipole kernel, which requires knowledge of the direction of the main magnetic fieldB ^ 0 $$ {\hat{\boldsymbol{B}}}_{\mathbf{0}} $$ with respect to the acquired image volume axes. The direction ofB ^ 0 $$ {\hat{\boldsymbol{B}}}_{\mathbf{0}} $$ is dependent on the axis and angle of rotation in oblique acquisition. Using both a numerical brain phantom and in vivo acquisitions in 5 healthy volunteers, we analyzed the effects of oblique acquisition on magnetic susceptibility maps. We compared three tilt-correction schemes at each step in the QSM pipeline: phase unwrapping, background field removal and susceptibility calculation, using the RMS error and QSM-tuned structural similarity index.

RESULTS

Rotation of wrapped phase images gave severe artifacts. Background field removal with projection onto dipole fields gave the most accurate susceptibilities when the field map was first rotated into alignment withB ^ 0 $$ {\hat{\boldsymbol{B}}}_{\mathbf{0}} $$ . Laplacian boundary value and variable-kernel sophisticated harmonic artifact reduction for phase data background field removal methods gave accurate results without tilt correction. For susceptibility calculation, thresholded k-space division, iterative Tikhonov regularization, and weighted linear total variation regularization, all performed most accurately when local field maps were rotated into alignment withB ^ 0 $$ {\hat{\boldsymbol{B}}}_{\mathbf{0}} $$ before susceptibility calculation.

CONCLUSION

For accurate QSM, oblique acquisition must be taken into account. Rotation of images into alignment withB ^ 0 $$ {\hat{\boldsymbol{B}}}_{\mathbf{0}} $$ should be carried out after phase unwrapping and before background-field removal. We provide open-source tilt-correction code to incorporate easily into existing pipelines: https://github.com/o-snow/QSM_TiltCorrection.git.

Recent technologies in cardiac imaging

Cardiac imaging allows physicians to view the structure and function of the heart to detect various heart abnormalities, ranging from inefficiencies in contraction, regulation of volumetric input and output of blood, deficits in valve function and structure, accumulation of plaque in arteries, and more. Commonly used cardiovascular imaging techniques include x-ray, computed tomography (CT), magnetic resonance imaging (MRI), echocardiogram, and positron emission tomography (PET)/single-photon emission computed tomography (SPECT). More recently, even more tools are at our disposal for investigating the heart's physiology, performance, structure, and function due to technological advancements. This review study summarizes cardiac imaging techniques with a particular interest in MRI and CT, noting each tool's origin, benefits, downfalls, clinical application, and advancement of cardiac imaging in the near future.

Recent Advance of Liposome Nanoparticles for Nucleic Acid Therapy

Gene therapy, as an emerging therapeutic approach, has shown remarkable advantages in the treatment of some major diseases. With the deepening of genomics research, people have gradually realized that the emergence and development of many diseases are related to genetic abnormalities. Therefore, nucleic acid drugs are gradually becoming a new boon in the treatment of diseases (especially tumors and genetic diseases). It is conservatively estimated that the global market of nucleic acid drugs will exceed $20 billion by 2025. They are simple in design, mature in synthesis, and have good biocompatibility. However, the shortcomings of nucleic acid, such as poor stability, low bioavailability, and poor targeting, greatly limit the clinical application of nucleic acid. Liposome nanoparticles can wrap nucleic acid drugs in internal cavities, increase the stability of nucleic acid and prolong blood circulation time, thus improving the transfection efficiency. This review focuses on the recent advances and potential applications of liposome nanoparticles modified with nucleic acid drugs (DNA, RNA, and ASO) and different chemical molecules (peptides, polymers, dendrimers, fluorescent molecules, magnetic nanoparticles, and receptor targeting molecules). The ability of liposome nanoparticles to deliver nucleic acid drugs is also discussed in detail. We hope that this review will help researchers design safer and more efficient liposome nanoparticles, and accelerate the application of nucleic acid drugs in gene therapy.

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.

Course of Cardiac Magnetic Resonance Imaging Findings in Acute Myocarditis after COVID-19 mRNA Vaccination

Myocarditis is being increasingly reported as a rare complication of coronavirus disease 2019 (COVID-19) mRNA vaccines. We herein report a case of myocarditis following COVID-19 mRNA vaccination in a man. Cardiac magnetic resonance imaging (CMRI) revealed an area of high signal intensity on short T1 inversion recovery (STIR) and late gadolinium enhancement (LGE), which are characteristic of myocarditis. Follow-up CMRI performed six months later revealed improvement in the myocardial edema and LGE findings. CMRI is a useful non-invasive imaging modality for making an initial diagnosis as well as for follow-up in cases of myocarditis after COVID-19 mRNA vaccination.

Systemic Emergencies in COVID-19 Patient: A Pictorial Review

Since the first report of the outbreak in Wuhan, China in December 2019, as of 1 September 2021, the World Health Organization has confirmed more than 239 million cases of the novel coronavirus (SARS-CoV-2) infectious disease named coronavirus disease 2019 (COVID-19), with more than 4.5 million deaths. Although SARS-CoV-2 mainly involves the respiratory tract, it is considered to be a systemic disease. Imaging plays a pivotal role in the diagnosis of all manifestations of COVID-19 disease, as well as its related complications. The figure of the radiologist is fundamental in the management and treatment of the patient. The authors try to provide a systematic approach based on an imaging review of major multi-organ manifestations of this infection.

Dynamic contrast-enhanced (DCE) imaging: state of the art and applications in whole-body imaging

Dynamic contrast-enhanced (DCE) imaging is a non-invasive technique used for the evaluation of tissue vascularity features through imaging series acquisition after contrast medium administration. Over the years, the study technique and protocols have evolved, seeing a growing application of this method across different imaging modalities for the study of almost all body districts. The main and most consolidated current applications concern MRI imaging for the study of tumors, but an increasing number of studies are evaluating the use of this technique also for inflammatory pathologies and functional studies. Furthermore, the recent advent of artificial intelligence techniques is opening up a vast scenario for the analysis of quantitative information deriving from DCE. The purpose of this article is to provide a comprehensive update on the techniques, protocols, and clinical applications - both established and emerging - of DCE in whole-body imaging.

Unenhanced Cardiac Magnetic Resonance may improve detection and prognostication of an occult heart involvement in asymptomatic patients with systemic sclerosis

Systemic sclerosis (SSc) is an uncommon autoimmune disease. Aim of the study was to detect the occult cardiac involvement in asymptomatic SSc patients of recent onset (indicative of a more aggressive disease) with unenhanced Cardiac Magnetic Resonance (CMR). Our historical prospective study included naïve SSc patients of recent onset. Modified Rodnan Skin Score (mRSS) and Scleroderma Clinical Trial Consortium Damage Index (SCTC-DI) were calculated. Cardiac volumes and global myocardial strain were assessed and also compared with healthy group values. Pericardial involvement was further recorded. Thirty-one patients met inclusion criteria (54 ± 12 years; 1 M). Mean duration of disease was 6.8 years. All patients showed preserved systolic function. Higher incidence of pericardial involvement was founded in patients with disease accrual damage (OR: 9.6, p-value 0.01). Radial and longitudinal strain values resulted significantly different between healthy and SSc patients. GRS and GLS showed an independent predictive validity on damage accrual (HR: 1.22 and 1.47, respectively). Best C-index for disease progression was reached when strain values and pericardial evaluation were added to conventional risk factors (0.97, p-value: 0.0001). Strain analysis by CMR-TT may show a high capability both in identifying early cardiac involvement and stratifying its clinical aggressiveness, regardless of the standard damage indices and CMR contrast-dependent biomarker.

Stress Perfusion Cardiac Magnetic Resonance in Long-Standing Non-Infarcted Chronic Coronary Syndrome with Preserved Systolic Function

(1) Background: The impact of imaging-derived ischemia is still under debate and the role of stress perfusion cardiac magnetic resonance (spCMR) in non-high-risk patient still needs to be clarified. The aim of this study was to evaluate the impact of spCMR in a case series of stable long-standing chronic coronary syndrome (CCS) patients with ischemia and no other risk factor. (2) Methods: This is a historical prospective study including 35 patients with history of long-standing CCS who underwent coronary CT angiography (CCTA) and additional adenosine spCMR. Clinical and imaging findings were included in the analysis. Primary outcomes were HF (heart failure) and all major cardiac events (MACE) including death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, or resuscitated cardiac arrest. (3) Results: Mean follow-up was 3.7 years (IQR: from 1 to 6). Mean ejection fraction was 61 ± 8%. Twelve patients (31%) referred primary outcomes. Probability of experiencing primary outcomes based on symptoms was 62% and increased to 67% and 91% when multivessel disease and ischemia, respectively, were considered. Higher ischemic burden was predictive of disease progression (OR: 1.59, 95%CI: 1.18–2.14; p-value = 0.002). spCMR model resulted non inferior to the model comprising all variables (4) Conclusions: In vivo spCMR-modeling including perfusion and strain anomalies could represent a powerful tool in long-standing CCS, even when conventional imaging predictors are missing.

Real-world clinical validity of cardiac magnetic resonance tissue tracking in primitive hypertrophic cardiomyopathy

OBJECTIVE

Cardiac magnetic resonance (CMR) is an uncontested diagnostic tool for identifying and assessing hypertrophic cardiomyopathy (HCM) patients. Concerning the necessity to identify valid prognosticators for predicting the individual risk of clinical evolution, this study aimed to evaluate the clinical validity of CMR tissue tracking (TT) analysis in patients affected by primitive HCM in a real-world setting.

METHODS

This historical prospective study included 33 patients. Diagnostic validity and clinical validation were assessed for strain values. CMR-TT diagnostic validity was studied comparing HCM patients with healthy control groups and phenotypic presentation of HCM. The impact of strain values and all phenotypic disease characteristics were assessed in a long-term follow-up study.

RESULTS

The inter-reading agreement was good for all strain parameters. Significant differences were observed between the control group and HCM patients. Similarly, hypertrophic and LGE + segments showed lower deformability than healthy segments. The AUC of predictive model, including conventional risk factors for MACE occurrence and all strain values, reached 98% of diagnostic concordance (95% CI .94-1; standard error: .02; p value .0001), compared to conventional risk factors only (86%; 95% CI .73-99; standard error: .07; p value .002).

CONCLUSION

In patients with primitive HCM, CMR-TT strain proves high clinical validity providing independent and non-negligible prognostic advantages over clinical features and traditional CMR markers.

Cardiac Effects of Treadmill Running at Different Intensities in a Rat Model

Purpose: In this study, we investigated the effect of treadmill exercise training on cardiac hypertrophy, collagen deposition, echo parameters and serum levels of cardiac troponin I (cTnI) in rats, and how they differ with various exercise intensities, hence exploring potential signal transduction. Methods: Male Sprague-Dawley rats were randomly divided into sedentary (SED), low-intensity running (LIR), medium-intensity running (MIR), and high-intensity running (HIR) groups. Each exercise group had 3 subgroups that were sacrificed for cardiac tissue analyses at 1, 4, and 8 weeks, respectively, and all rats participated in a daily 1 h treadmill routine 5 days per week. Echocardiographic measurements were performed 24 h after the last exercise session. Additionally, myocardium samples and blood were collected for histological and biochemical examinations. Changes in the extracellular signal-regulated kinases 1/2 (ERK1/2) signal pathway were detected by Western blotting. Results: After a week of running, ventricular myocyte size and the phosphorylation of ERK1/2 increased in the HIR group, while left ventricular (LV) diastolic diameter values and LV relative wall thickness increased in the LIR and MIR groups. In addition, we observed heart enlargement, cTnI decrease, and ERK1/2 signal activation in each of the exercise groups after 4 weeks of running. However, the HIR group displayed substantial rupture and increased fibrosis in myocardial tissue. In addition, compared with the LIR and MIR groups, 8 weeks of HIR resulted in structural damage, fiber deposition, and increased cTnI. However, there was no difference in the activation of ERK1/2 signaling between the exercise and SED groups. Conclusion: The effect of running on cardiac hypertrophy was intensity dependent. In contrast to LIR and MIR, the cardiac hypertrophy induced by 8 weeks of HIR was characterized by potential cardiomyocyte injury, which increased the risk of pathological development. Furthermore, the ERK signaling pathway was mainly involved in the compensatory hypertrophy process of the myocardium in the early stage of exercise and was positively correlated with exercise load. However, long-term exercise may attenuate ERK signaling activation.