Current cardiac imaging techniques for detection of left ventricular mass

Enhanced classification of left ventricular hypertrophy in cardiac patients using extended Siamese CNN

Objective.Left ventricular hypertrophy (LVH) is the thickening of the left ventricle wall of the heart. The objective of this study is to develop a novel approach for the accurate assessment of LVH) severity, addressing the limitations of traditional manual grading systems.Approach.We propose the Multi-purpose Siamese Weighted Euclidean Distance Model (MSWED), which utilizes convolutional Siamese neural networks and zero-shot/few-shot learning techniques. Unlike traditional methods, our model introduces a cutoff distance-based approach for zero-shot learning, enhancing accuracy. We also incorporate a weighted Euclidean distance targeting informative regions within echocardiograms.Main results.We collected comprehensive datasets labeled by experienced echocardiographers, including Normal heart and various levels of LVH severity. Our model outperforms existing techniques, demonstrating significant precision enhancement, with improvements of up to 13% for zero-shot and few-shot learning approaches.Significance.Accurate assessment of LVH severity is crucial for clinical prognosis and treatment decisions. Our proposed MSWED model offers a more reliable and efficient solution compared to traditional grading systems, reducing subjectivity and errors while providing enhanced precision in severity classification.

Association Between Major Adverse Cardiovascular Events and Left Ventricular Mass Index in Patients Who Have Undergone Coronary Computed Tomography Angiography: From the FU-CCTA Registry

Background

Left ventricular mass (LVM) is a predictor of future cardiovascular risk. We determined the association between LVM measured by coronary computed tomography angiography (CCTA) and the prognosis in patients who have undergone CCTA for screening of coronary artery disease (CAD).

Methods

We performed a prospective cohort study. Five hundred twenty consecutive patients who underwent CCTA at Fukuoka University Hospital (FU-CCTA registry) were enrolled. They were clinically suspected of having CAD or had at least one cardiovascular risk factor, and were a follow-up of up to 5 years. Equal to more than 50% of coronary stenosis as assessed by CCTA was diagnosed as CAD. Using CCTA, LVM index (LVMI), LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV) and LV end-systolic volume were measured. The primary endpoint was major adverse cardiovascular events (MACEs: including all causes of death, ischemic stroke, acute myocardial infarction and coronary revascularization). The patients were divided into non-MACEs and MACEs groups.

Results

The non-MACEs and MACEs groups consisted of 478 and 42 patients, respectively. Percent of CAD in the MACEs group was significantly higher than that in the non-MACEs group. The MACEs group showed significantly higher LVMI and tended to have a lower LVEF and LVEDV than the non-MACEs group. Although LVMI was not associated with MACEs in all patients, LVMI was independently associated with MACEs in males (odd ratio: 1.018, 95% confidence interval: 1.002 - 1.035, P = 0.030), but not females.

Conclusions

Evaluation of LVMI by CCTA may be useful for predicting MACEs in males.

An Overview of Deep Learning Methods for Left Ventricle Segmentation

Cardiac health diseases are one of the key causes of death around the globe. The number of heart patients has considerably increased during the pandemic. Therefore, it is crucial to assess and analyze the medical and cardiac images. Deep learning architectures, specifically convolutional neural networks have profoundly become the primary choice for the assessment of cardiac medical images. The left ventricle is a vital part of the cardiovascular system where the boundary and size perform a significant role in the evaluation of cardiac function. Due to automatic segmentation and good promising results, the left ventricle segmentation using deep learning has attracted a lot of attention. This article presents a critical review of deep learning methods used for the left ventricle segmentation from frequently used imaging modalities including magnetic resonance images, ultrasound, and computer tomography. This study also demonstrates the details of the network architecture, software, and hardware used for training along with publicly available cardiac image datasets and self-prepared dataset details incorporated. The summary of the evaluation matrices with results used by different researchers is also presented in this study. Finally, all this information is summarized and comprehended in order to assist the readers to understand the motivation and methodology of various deep learning models, as well as exploring potential solutions to future challenges in LV segmentation.

Evaluation of Left Ventricular Mass in Different Cardiac Geometry Using Three-Dimensional Contrast-Enhanced Echocardiography

A total of 69 patients were enrolled in the study, including 23 patients with hypertrophic cardiomyopathy (HCM), 26 patients with Left Ventricle (LV) enlargement comprising 16 dilated cardiomyopathy (DCM) patients and 10 ischemic cardiomyopathy (ICM) patients, and 20 control subjects. All patients underwent 2DE, contrast-enhanced 2DE (Contrast-2DE), 3DE, Contrast-3DE, and single photon emission computed tomography (SPECT) examinations. The 2DE-AL and 3DE methods measured the left ventricular mass (LVM). The results were compared with those measured by SPECT. The measured LVM of the 69 patients was systematically overestimated by 2DE-AL (177.4 ± 56.2 g), Contrast-2DE-AL (174.5 ± 55.5 g), 3DE (167.3 ± 59.2 g), and Contrast-3DE (154.2 ± 46.7 g) when compared with SPECT (148.5 ± 52.4 g) (P < 0.05), while Contrast-3DE provided the best agreement with SPECT in LVM measurement (r = 0.898, P < 0.001) and had the smallest deviation (5.7 ± 23.1 g). 3DE overestimated LVM more compared to Contrast-3DE in LV hypertrophy group (165.5 ± 37.9 g versus 153.5 ± 27.6 g, P = 0.003) and LV enlargement group (204.5 ± 69.3 g versus 183.5 ± 53.5 g, P = 0.006). For 2DE methods, there was no significant difference between the LVM obtained with or without contrast enhancement in control group (132.3 ± 23.6 g versus 128.4 ± 23.3 g), LV hypertrophy group (177.7 ± 38.6 versus 178.3 ± 30.9 g, P = 0.889), and LV enlargement group (211.9 ± 63.2 g versus 206.5 ± 66.0 g, P = 0.386). The difference between LVM measured by 2DE-AL and SPECT was the greatest (27.9 ± 34.0 g), especially in LV hypertrophy group and LV enlargement group (LV hypertrophy group 39.7 ± 26.0 g; LV enlargement group 24.2 ± 42.8 g). To conclude, Contrast-3DE and SPECT show greater consistency in LVM measurement, especially in cardiomyopathy, when compared with 2DE. Administering contrast can effectively reduce the overestimation of LVM by non-contrast DE.

Micro-CT scan with virtual dissection of left ventricle is a non-destructive, reproducible alternative to dissection and weighing for left ventricular size

Micro-CT scan images enhanced by iodine staining provide high-resolution visualisation of soft tissues in laboratory mice. We have compared Micro-CT scan-derived left ventricular (LV) mass with dissection and weighing. Ex-vivo micro-CT scan images of the mouse hearts were obtained following staining by iodine. The LV was segmented and its volume was assessed using a semi-automated method by Drishti software. The left ventricle was then dissected in the laboratory and its actual weight was measured and compared against the estimated results. LV mass was calculated multiplying its estimated volume and myocardial specific gravity. Thirty-five iodine-stained post-natal mouse hearts were studied. Mice were of either sex and 68 to 352 days old (median age 202 days with interquartile range 103 to 245 days) at the time of sacrifice. Samples were from 20 genetically diverse strains. Median mouse body weight was 29 g with interquartile range 24 to 34 g. Left Ventricular weights ranged from 40.0 to 116.7 mg. The segmented LV mass estimated from micro-CT scan and directly measured dissected LV mass were strongly correlated (R² = 0. 97). Segmented LV mass derived from Micro-CT images was very similar to the physically dissected LV mass (mean difference = 0.09 mg; 95% confidence interval − 3.29 mg to 3.1 mg). Micro-CT scanning provides a non-destructive, efficient and accurate visualisation tool for anatomical analysis of animal heart models of human cardiovascular conditions. Iodine-stained soft tissue imaging empowers researchers to perform qualitative and quantitative assessment of the cardiac structures with preservation of the samples for future histological analysis.

Effect of etelcalcetide on cardiac hypertrophy in hemodialysis patients: a randomized controlled trial (ETECAR-HD)

Background

Fibroblast growth factor 23 (FGF23) is associated with left ventricular hypertrophy (LVH) in patients with chronic kidney disease, and calcimimetic therapy reduces plasma concentrations of FGF23. It remains unknown whether treatment with the calcimimetic etelcalcetide (ETL) reduces LVH in patients on hemodialysis.

Methods/design

This single-blinded randomized trial of 12 months duration will test the effects of ETL compared with alfacalcidol on LVH and cardiac fibrosis in maintenance hemodialysis patients with secondary hyperparathyroidism. Both treatment regimens will be titrated to equally suppress secondary hyperparathyroidism while alfacalcidol treatment causes an increase and ETL a decrease in FGF23, respectively.

Patients treated thrice weekly with hemodialysis for ≥ 3 months and ≤ 3 years with parathyroid hormone levels ≥ 300 pg/ml and LVH will be enrolled in the study.

The primary study endpoint is change from baseline to 12 months in left ventricular mass index (LVMI; g/m²) measured by cardiac magnetic resonance imaging. Sample size calculations showed that 62 randomized patients will be necessary to detect a difference in LVMI of at least 20 g/m² between the two groups at 12 months. Due to the strong association of volume overload and LVH, randomization will be stratified by residual kidney function, and regular body composition monitoring will be performed to control the volume status of patients.

Study medication will be administered intravenously by the dialysis nurses after every hemodialysis session, thus omitting adherence issues.

Secondary study endpoints are cardiac parameters measured by echocardiography, biomarker concentrations of bone metabolism (FGF23, vitamin D, parathyroid hormone, calcium, phosphate, s-Klotho), cardiac markers (pro-brain natriuretic peptide, pre- and postdialysis troponin T) and metabolites of the renin–angiotensin–aldosterone cascade (angiotensin I (Ang I), Ang II, Ang-(1–7), Ang-(1–5), Ang-(1–9), and aldosterone).

Discussion

The causal inference and pathophysiology of LVH regression by FGF23 reduction using calcimimetic treatment has not yet been shown. This intervention study has the potential to discover a new strategy for the treatment of cardiac hypertrophy and fibrosis in patients on maintenance hemodialysis. It might be speculated that successful treatment of cardiac morphology will also reduce the risk of cardiac death in this population.

Trial registration

European Clinical Trials Database, EudraCT number 2017-000222-35; ClinicalTrials.gov, NCT03182699. Registered on

Cardiac left ventricular myocardial tissue density, evaluated by computed tomography and autopsy

BACKGROUND

Left ventricular mass (LVM) is an independent risk factor for the prediction of cardiac events. Its assessment is a clinically important diagnostic procedure in cardiology and may be performed by Computed Tomography (CT). The aim of this study was to assess the correlation between the cardiac left ventricular shell volume (LVShV) determined by postmortem Computed Tomography (PMCT) and the anatomic LVM obtained at autopsy and to calculate the myocardial tissue density.

METHODS

A total of 109 deceased individuals were examined with a 64-slice CT scanner and LVShV was determined. At autopsy, the left ventricle was dissected and weighted. The correlation between LVShV and the anatomic LVM was analysed. Asymmetric left ventricular (LV) hypertrophy was recorded. Inter-observer variability was evaluated, and a density value for myocardial tissue was calculated.

RESULTS

The mean age of the deceased was 55 ± 16 years, and 58% was men. We found 30 cases of asymmetric LV hypertrophy. A highly positive correlation existed between LVShV and anatomic LVM (r = 0.857; p < 0.0001), regardless of hypertrophy, asymmetric hypertrophy and gender. The mean difference in the inter-observer variability for LVShV assessment was - 4.4 ml (95% CI: -26.4; 17.6). A linear regression analysis was performed, resulting in a value of 1.265 g/ml for myocardial tissue density. Applying the hitherto used myocardial tissue density of 1.055 g/ml underestimated the anatomic LVM by 18.1% (p < 0.0001).

CONCLUSION

PMCT is a helpful tool for the assessment of LVM, and LVShV is highly correlated with LVM as assessed by subsequent autopsy. The correlation between the two was independent of gender, hypertrophy and LV asymmetric hypertrophy. We found a higher myocardial tissue density of 1.265 g/ml compared to previous studies. We show that PMCT combined with autopsy may contribute not only to anatomical but also clinical knowledge.

Bringing Cardiovascular Comorbidities in Acromegaly to an Update. How Should We Diagnose and Manage Them?

Patients with acromegaly frequently develop cardiovascular comorbidities, which significantly affect their morbidity and contribute to an increased all-cause mortality. In this regard, the most frequent complications that these patients may encounter include hypertension, cardiomyopathy, heart valve disease, arrhythmias, atherosclerosis, and coronary artery disease. The specific underlying mechanisms involved in the pathophysiology of these comorbidities are not always fully understood, but uncontrolled GH/IGF-I excess, age, prolonged disease duration, and coexistence of other cardio-vascular risk factors have been identified as significant influencing predisposing factors. It is important that clinicians bear in mind the potential development of cardiovascular comorbidities in acromegalic patients, in order to promptly tackle them, and avoid the progression of cardiac abnormalities. In many cases, this approach may be performed using straightforward screening tools, which will guide us for further diagnosis and management of cardiovascular complications. This article focuses on those cardiovascular comorbidities that are most frequently encountered in acromegalic patients, describes their pathophysiology, and suggests some recommendations for an early and optimal diagnosis, management and treatment.

Intravital and postmortem diagnostics of myocardial hypertrophy of the left ventricle:identity or convention?

AIM

The aim of the study is to assess the compliance of the results of electrocardiographic (ECG) and echocardiographic diagnostic methods of hypertrophy of left ventricular myocardium (LVH) with the postmortem finding of measurement of left ventricular myocardium mass (LVM).

MATERIALS AND METHODS

We examined the data of intravital study of anthropometric measurements [age, height, weight, body mass index (BMI)], instrumental results [12-lead ECG, EchoCG], as well as the postmortem finding (direct measurement of LVM at autopsy) in 15 patients of general therapy department. While analyzing ECG we studied as conventional ECG criteria for the detection of LVH as well as the author's own criteria based on two models (regression and discriminant analyses), including voltage, sex and age criteria. Echocardiographic diagnostic method used to calculate LVM (according to ASE formula) and left ventricular mass index (LVMI). Postmortem finding of LVM was carried out according to the standard measurement method. According to the absence of the single conventional postmortem finding of measurement of LVH, we considered three different variants of the postmortem finding of LVH: the criterion of K. Bove et al. (CB); the criterion of A.M. Lifshitz, also called ventricular index (VI) and the criterion of P. Casale - the left ventricular mass index at autopsy (LVMI).

RESULTS

Conventional ECG criteria for the detection of LVH showed high specificity (71-100%) using any method of the postmortem finding of measurement, but were characterized by extremely low sensitivity (0-37.5%). Their overall diagnostic accuracy was higher on using K. Bove or A.M. Lifshitz criteria (40-66.7%) and low - on using the criterion of P. Casale (13.3-40%). The author's ECG criteria were less specificity (50-100%) and had higher sensitivity (54-75%), and their diagnostic accuracy remained higher and showed small dependence on the method of the postmortem finding of measurement of LVH (60-66.7%).

CONCLUSION

Usually the ECG criteria to diagnose left ventricular hypertrophy were expectedly showed low sensitivity using any method of the postmortem finding of measurement. Meanwhile, the author's own ECG criteria associated with the most sensitive electrocardiographic characteristics to LVH and sex and age-specific indexes of the examined patients exceeded the conventional ECG criteria in sensitivity and diagnostic accuracy.

Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters

Left ventricular (LV) mass is a strong predictor of cardiovascular disease (CVD) events; increased LV mass is common among US firefighters and plays a major role in firefighter sudden cardiac death. We aim to identify significant predictors of LV mass among firefighters. Cross-sectional study of 400 career male firefighters selected by an enriched randomization strategy. Weighted analyses were performed based on the total number of risk factors per subject with inverse probability weighting. LV mass was assessed by echocardiography (ECHO) and cardiac magnetic resonance, and normalized (indexed) for height. CVD risk parameters included vital signs at rest, body mass index (BMI)–defined obesity, obstructive sleep apnea risk, low cardiorespiratory fitness, and physical activity. Linear regression models were performed. In multivariate analyses, BMI was the only consistent significant independent predictor of LV mass indexes (all, p <0.001). A 1-unit decrease in BMI was associated with 1-unit (g/m^1.7) reduction of LV mass/height^1.7 after adjustment for age, obstructive sleep apnea risk, and cardiorespiratory fitness. In conclusion, after height-indexing ECHO-measured and cardiac magnetic resonance–measured LV mass, BMI was found to be a major driver of LV mass among firefighters. Our findings taken together with previous research suggest that reducing obesity will improve CVD risk profiles and decrease on-duty CVD and sudden cardiac death events in the fire service. Our results may also support targeted noninvasive screening for LV hypertrophy with ECHO among obese firefighters.

Is the Increased Septal Perfusion the Signal of Asymmetrical Septal Hypertrophy?

In this study, we have compared scintigraphic and echocardiographic data in order to investigate whether increased septal perfusion represents asymmetrical septal hypertrophy (ASH), which is a symptom followed in the scintigraphy of myocardial perfusion. The study consists of a total of 186 patients (120 females and 66 males with an average age of 59.45 ± 11.54 years) who had normal myocardial perfusion scintigraphy and echocardiography examinations. Statistical comparison of septal wall thickness measurements obtained from echocardiography and septal-to-lateral wall ratios (S/L ratio) was performed scintigraphically. Left ventricular mass values were obtained as both scintigraphic and echocardiographic data and their correlations were evaluated in order to assess the presence of left ventricular hypertrophy (LVH). In statistical analyses, the values of interventricular septal thickness in diastole (IVSd), left ventricle posterior wall thickness in diastole (LVPWd), left ventricle mass (LVM), and left ventricle mass index (LVMI) were found to be significantly higher in group 2 (S/L ratio >1) compared to group 1 (S/L ratio <1). In addition, S/L ratio is significantly correlated with echocardiographic IVSd, LVPWd, LVM, LVMI, and scintigraphic LVM (rest) values. Furthermore, echocardiographic LVM and LVMI values were significantly correlated with LVM and LVMI values obtained from scintigraphy. It should be known that increased S/L ratio that can be monitored during scintigraphic studies can be an indicator of septal hypertrophy and/or LVH, however, further examination and close follow-ups should be performed in necessary cases.

Cardiac CT assessment of left ventricular mass in mid-diastasis and its prognostic value

AIMS

To determine the influence of cardiac motion on measurements of left ventricular (LV) mass obtained with 64-slice computed tomography (CT) and to elucidate the prognostic value of LV mass on major adverse cardiac events (MACE) and all-cause mortality. Increased LV mass has been linked with MACE. Although Cardiac CT allows measurement of LV anatomy, it is susceptible to motion artefacts often requiring image acquisition during diastasis. There is a need to understand variability in LV mass measurements across phases of the cardiac cycle, and whether mid-diastolic measurements have prognostic value.

METHODS AND RESULTS

The study comprised two equally sized cohorts of patients that had undergone retrospectively gated cardiac CT: patients who had MACE and/or all-cause death at follow-up and a matched (age, sex, and risk factors) event-free cohort. LV mass was measured at mid-diastole, end-diastole, and end-systole. Correlation and agreement between phases were determined. The incremental value of mid-diastolic hypertrophy (LVH) over the National Cholesterol Education Programme (NCEP) risk was performed for LV mass indices normalized to body surface area (LVMI_BSA) or weight (LVMI_Weight). Of 166 patients, 31.3% experienced MACE and 28.9% died of any cause (follow-up 22.9 ± 13.4 months). LV mass at all cardiac phases were strongly correlated (r > 0.94). Mean mid-diastolic LVMI_BSA was higher in the cohort with events (93.7 vs. 80.7 g/m², P= 0.008) as was LVMI_Weight (2.26 vs. 1.88 g/kg, P = 0.001). LVMI_BSA and LVMI_Weight had prognostic value incremental to NCEP with 1.85 and 2.47 hazard ratios, respectively.

CONCLUSIONS

Measurement of LV mass can be obtained by cardiac CT images obtained at mid-diastasis. LV mass measurements obtained at mid-diastasis have prognostic value.

Low Frequency of Cardiomyopathy Using Cardiac Magnetic Resonance Imaging in an Acromegaly Contemporary Cohort

CONTEXT

Left ventricular hypertrophy (LVH) and myocardial fibrosis are considered common findings of the acromegaly cardiomyopathy in echocardiography studies.

OBJECTIVE

To evaluate the frequency of LVH, systolic dysfunction and myocardial fibrosis was undertaken in patients with acromegaly using cardiac magnetic resonance imaging (CMRi) before and after 12 months of octreotide long-acting repeatable treatment.

PATIENTS AND METHODS

Consecutive patients with active acromegaly submitted to biochemical analysis and CMRi before and after 12 months of treatment. Additionally, echocardiography was performed before treatment.

RESULTS

Forty consecutive patients were evaluated using CMRi at baseline and 30 patients were reevaluated after 12 months of treatment. Additionally, 29 of these patients were submitted to echocardiography. Using CMRi, the frequency of LVH was 5%. The mean left ventricular mass index (LVMi) was 61.73 ± 18.8 g/m(2). The mean left ventricular ejection fraction (LVEF) was 61.85 ± 9.2%, and all patients had normal systolic function. Late gadolinium enhancement was present in five patients (13.5%), and one patient (3.5%) had an increased extracellular volume. After treatment, 12 patients (40%) had criteria for disease control. No clinically relevant differences in cardiac variables before and after treatment were observed. Additionally, there was no difference in LVMi and LVEF among patients with and without disease control. Using echocardiography, 31% of the patients had LVH, mean LVMi was 117.8 ± 46.3 g/m(2) and mean LVEF was 67.3 ± 4.4%. All patients had normal systolic function.

CONCLUSIONS

We demonstrated by CMRi, the gold-standard method, that patients with active acromegaly might have a lower prevalence of cardiac abnormalities than previously reported.

Porcupine Quill Migration in the Thoracic Cavity of a German Shorthaired Pointer

A 7 yr old German shorthaired pointer presented with progressive respiratory distress and lethargy. Two weeks prior to presentation, the dog had porcupine quills removed from the left forepaw, muzzle, and sternal area. At the time of presentation, the dog had bounding pulses and friction rubs in the right dorsal lung field. Harsh lung sounds and decreased lung sounds were ausculted in multiple lung fields. Radiographs revealed a pneumothorax and rounding of the cardiac silhouette suggestive of pericardial effusion. Computed tomographic imaging was performed and revealed multiple porcupine quills in the thoracic cavity. Surgery was performed and quills were found in multiple lung lobes and the heart. Following surgery the dog remained hypotensive. A post-operative echocardiogram revealed multiple curvilinear soft-tissue opacities in the heart. Given the grave prognosis the dog was subsequently euthanized and a postmortem examination was performed. A single porcupine quill was discovered in the left atrium above the mitral valve annulus. The quill extended across the aortic root, impinging on the coronary artery below the level of the aortic valve. To the authors' knowledge, this is the first known report of porcupine quill migration through the heart.