Magnetic resonance imaging reference values for cardiac morphology, function and tissue composition in adolescents

Age-, body surface area-, and sex-specific reference values for cardiovascular magnetic resonance imaging derived ventricular and atrial size and function for Chinese healthy children

BACKGROUND

Cardiovascular magnetic resonance (CMR) is crucial for the diagnosis and prognosis of heart disease. However, normal reference values for CMR-derived morphology parameters have not been established for Chinese children. We sought to establish reference values for ventricular and atrial size and function parameters using CMR in healthy Chinese children across a broad age range.

METHODS

3T CMR scans were performed in 191 healthy children, aged 4-18 years. We used balanced steady-state free precession sequence for analyzing chamber size and function. Reference percentile curves and tables were generated using the generalized additive model for location scale and shape. A meta-analysis was conducted to compare our results with those of relevant previously published studies.

RESULTS

Boys generally had greater ventricular volumes and masses after normalization for body surface area (BSA) compared with girls. However, in the youngest age group (4-8 years), differences in volumes or masses between sexes were not found. Additionally, differences were not observed in left ventricular and right ventricular ejection fractions between sexes upon stratifying subjects based on age groups. However, after normalizing for BSA, only the maximal right atrial volume remained significantly greater in boys than that in girls. Age-specific and BSA-specific reference curves revealed non-linear relationships between age/BSA and cardiac parameters. Asian children exhibited significantly smaller chamber sizes compared to those seen in Caucasian children.

CONCLUSION

We report normative CMR ventricular and atrial volume and function in Chinese children based on BSA, age, and sex, which can serve as a reference for future studies and clinical practice.

CMR native T1 and T2 mapping in Olympic athletes: the influence of sports discipline and sex

AIMS

Cardiac magnetic resonance (CMR) has a growing role in evaluating athletes' hearts. Mapping techniques provide added value for tissue characterization, but data on athletes and sports disciplines are lacking. To describe native mapping values in a cohort of Olympic athletes and evaluate the influence of sports discipline and sex.

METHODS AND RESULTS

A group of 300 Olympic athletes (13% skill, 20% power, 25% mixed, 42% endurance, 58% male) with unremarkable cardiovascular screening and a control group of 42 sedentary subjects (52% male) underwent CMR without contrast administration. Athletes were divided based on sex and sports categories according to the ESC classification. Among athletes of different sports categories and controls, endurance presented the lowest value of T1 mapping (P < 0.001). No differences in T2 mapping were observed (P = 0.472). Female athletes had higher values of T1 native myocardial mapping compared with males (P = 0.001), while there were no differences in T2 mapping (P = 0.817). Male athletes with higher left ventricular mass indexed (LV-Massi) had lower values of T1 mapping (P = 0.006) and slightly higher values of T2 mapping, even if not significant (P = 0.150). Female athletes with higher LV-Massi did not show significant differences in T1 and T2 mapping (P = 0.053 and P = 0.438).

CONCLUSION

T1 native myocardial mapping showed significant differences related to sports disciplines and gender. Athletes with the largest LV remodelling, mostly endurance and mixed, showed the lowest values of T1 mapping. Male athletes showed lower values of T1 mapping than females. No significant differences were observed in T2 mapping related to sports disciplines and gender.

Adolescent Reference Values for MR-Derived Biventricular Strain Obtained Using Feature-Tracking and Myocardial Tagging

BACKGROUND

Myocardial strain is a promising marker for the detection of early left or right ventricular (LV or RV) dysfunction in pediatric populations. The reference standard for MR strain measurement is myocardial tagging (MT); however, MT has limited clinical utility because the additional acquisitions needed are time-consuming. In contrast, MR-feature tracking (FT) allows strain quantification from routinely acquired cine sequences. Studies providing reference values obtained with both FT and MT for adolescents are lacking.

PURPOSE

To use MR-FT and MT to define sex-specific LV and RV strain reference values for adolescents.

STUDY TYPE

Cross-sectional, prospective.

POPULATION

One hundred twenty-three adolescents aged 15-18 years (52% girls) without known cardiovascular disease.

FIELD STRENGTH/SEQUENCE

Balanced steady-state free-precession sequence for FT analysis and a spatial modulation of magnetization hybrid TFE-EPI sequence for MT acquisitions at 3.0-T.

ASSESSMENT

Segment Medviso software was used to obtain longitudinal (LS) and circumferential (CS) strain for both ventricles, and radial strain (RS) for LV.

STATISTICAL TESTS

The Student t-test was used for between-sex comparisons of continuous variables. Sex-specific percentiles were calculated using the weighted average method. Intraobserver and interobserver agreement was assessed in 30 randomly selected studies using intraclass correlation coefficients (ICC). A P-value <0.05 was considered statistically significant.

RESULTS

FT-derived LVLS and LVCS were significantly higher in girls than in boys (-19.8% vs. -17.8% and -22.2% vs. -21.0%, respectively), as they were with MT (LVLS: -18.1% vs. -16.8%; LVCS: -20.8% vs. -19.7%). FT-LVRS was higher in girls than in boys (44.8% vs. 35.1%), while MT-LVRS was the opposite (18.6% vs. 22.7%). FT-RVLS was higher in girls (-23.4% vs. -21.3%), but there were no between-sex differences in MT-derived RVLS or RVCS. ICC values for intraobserver agreement were ≥0.89, whereas for interobserver agreement were <0.80 for MT-LVRS and ≥0.80 for all remaining parameters.

DATA CONCLUSION

This study provides sex-specific reference biventricular strain values obtained with MR-MT and MR-FT for adolescents aged 15-18 years. MR-FT may be a valid method for obtaining strain values in pediatric populations.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 3.

Right ventricular dysfunction: pathophysiology, experimental models, evaluation, and treatment

Interest in the right ventricle has substantially increased due to advances in knowledge of its pathophysiology and prognostic implications across a wide spectrum of diseases. However, we are still far from understanding the multiple mechanisms that influence right ventricular dysfunction, its evaluation continues to be challenging, and there is a shortage of specific treatments in most scenarios. This review article aims to update knowledge about the physiology of the right ventricle, its transition to dysfunction, diagnostic tools, and available treatments from a translational perspective.

Subclinical Myocardial Fibrosis in South African Youth With HIV: Results From the CTAAC-Heart Study

Background

Few data exist on myocardial fibrosis and inflammation in youth with HIV.

Methods

We performed cardiovascular magnetic resonance (CMR) on a cross section of South African youth: youth with perinatally acquired HIV (YPHIV) undergoing antiretroviral therapy (ART), youth with nonperinatally acquired HIV (YNPHIV) receiving ART, and youth without HIV. Quantile regression models were fit to assess the association between HIV status and CMR outcomes: subclinical fibrosis (late gadolinium enhancement [LGE] mass and fraction, native T1, extracellular volume) and inflammation (native T1, T2 mapping).

Results

Of 464 youth, 287 were YPHIV, 87 were YNPHIV, and 90 were HIV seronegative. The median age was 16 years (range, 11-24). LGE mass was higher in YPHIV and YNPHIV than in youth who were HIV seronegative (1.85 vs 2.00 vs 1.41 g, respectively), as was fraction (5.8% vs 6.4% vs 4.5%); native T1 was highest in YNPHIV. In adjusted analyses, when compared with youth with HIV seronegativity, YPHIV and YNPHIV exhibited higher LGE mass (β = 0.468, P = .001; β = 0.544, P = .002) and LGE fraction (β = 1.587, P < .001; β = 1.781, P < .001). CMR outcomes were similar between YPHIV and YNPHIV.

Conclusions

Despite ART use, YPHIV and YNPHIV appear to have higher subclinical myocardial fibrosis than youth who are HIV seronegative and healthy adults in South Africa and may benefit from early screening/monitoring for cardiovascular disease.

Absence of Myocardial Involvement After SARS-CoV-2 Vaccination in Asymptomatic Adolescents

This study aimed to evaluate the presence of subclinical myocardial damage in adolescents who were vaccinated against SARS-CoV-2. One hundred twenty asymptomatic adolescents with a mean age of 16.0 ± 0.4 years (51% girls) underwent cardiac magnetic resonance (CMR) imaging. SARS-CoV-2 IgG/IgM antibody testing was performed, and self-reported dates of confirmed SARS-CoV-2 infection and/or vaccination were collected. Participants were classified according to SARS-CoV-2 status as naïve (non-infected and unvaccinated, n = 74), infected (unvaccinated, n = 23), and vaccinated (independently of past infection status, n = 23). Biventricular volumes and ejection fraction and myocardial T2 relaxation time were similar in the three groups. T1 relaxation time was slightly higher in vaccinated adolescents (1249 ± 35 ms) than in naïve and infected participants (1231 ± 30 ms and 1227 ± 29 ms, respectively; p = 0.035), although this difference was considered clinically irrelevant. This observational study found no evidence of relevant subclinical myocardial involvement after SARS-CoV-2 vaccination in asymptomatic adolescents.