Biventricular Morphology and Function Reference Values Derived From a Large Sample of Healthy Chinese Adults by Magnetic Resonance Imaging

Cardiovascular MRI Reference Ranges for Heart, Aorta, and Pulmonary Artery in Healthy Chinese Children

BACKGROUND

Cardiovascular magnetic resonance (cardiac MR) reference ranges in Chinese children are lacking.

PURPOSE

To establish age- and sex-specific reference ranges for cardiac MR parameters in a cohort of healthy Chinese children.

STUDY TYPE

Retrospective.

SUBJECTS

One hundred ninety-six healthy children (mean age 9.5 ± 3.6 years, 111 boys).

FIELD STRENGTH/SEQUENCE

1.5 T; balanced steady-state free precession.

ASSESSMENT

Biventricular volume and ejection fractions (EF), left atrial (LA) volume, right atrial (RA) area, left ventricular (LV) mass and thickness, aortic root (AR), and main pulmonary artery (MPA) dimensions were measured. Parameters were compared between age groups and sex. The relationships between parameters and age, body mass index (BMI) and body surface area (BSA) were investigated.

STATISTICAL TESTS

Independent-samples t tests; Pearson's correlation. A P value <0.05 was considered statistically significant.

RESULTS

Generally, boys exhibited greater absolute measurements of LV volume (end-diastolic: 94.4 ± 29.5 vs. 81.3 ± 31.0 mL), LA volume (end-diastolic: 42.6 ± 13.4 vs. 38.0 ± 13.3 mL), RA area (end-diastolic: 11.6 ± 2.5 vs. 10.8 ± 2.6 cm2), LV thickness (base: 4.4 ± 1.1 vs. 3.8 ± 0.9 mm), AR dimensions (annuls: 16.3 ± 2.7 vs. 15.0 ± 2.8 mm), and MPA dimensions (14.3 ± 2.3 vs. 13.1 ± 2.4 mm) than girls did. However, these differences were not observed when the measurements were normalized to BSA (LV volume: 75.3 ± 11.7 vs. 71.9 ± 12.3 mL/m2, P = 0.052; LA volume: 34.8 ± 8.9 vs. 34.5 ± 7.6 mL/m2, P = 0.783; RA area: 9.7 ± 2.3 vs. 10.2 ± 2.3 cm2/m2, P = 0.107; LV thickness: 3.6 ± 0.7 vs. 3.6 ± 0.9 mm/m2, P = 0.990; AR: 13.6 ± 2.7 vs. 14.3 ± 3.4 mm/m2, P = 0.108; MPA: 11.9 ± 2.3 vs. 12.4 ± 2.4 mm/m2, P = 0.118). Boys had greater RV volume (end-diastolic: 98.7 ± 33.5 vs. 82.7 ± 33.1 mL) and LV mass (52.6 ± 20.2 vs. 41.4 ± 16.0 g) compared to girls, irrespective of whether the values were indexed or not for BSA. Additionally, there were significant associations between age, BMI, and BSA with biventricular volume, LA volume, RA area, LV mass and thickness, AR and MPA dimensions in both boys and girls.

DATA CONCLUSION

This study suggests reference ranges at 1.5 T for Chinese children.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Reference Ranges of Ventricular Morphology and Function in Healthy Chinese Adults: A Multicenter 3 T MRI Study

BACKGROUND

Magnetic resonance imaging (MRI) reference ranges for ventricular morphology and function in the Chinese population are lacking.

PURPOSE

To establish the MRI reference ranges of left and right ventricular (LV and RV) morphology and function based on a large multicenter cohort.

STUDY TYPE

Prospective.

POPULATION

One thousand and twelve healthy Chinese Han adults.

FIELD STRENGTH/SEQUENCE

Balanced steady-state free procession cine sequence at 3.0 T.

ASSESSMENT

Biventricular end-diastolic, end-systolic, stroke volume, and ejection fraction (EDV, ESV, SV, and EF), LV mass (LVM), end-diastolic and end-systolic dimension (LVEDD and LVESD), anteroseptal wall thickness (AS), and posterolateral wall thickness (PL) were measured. Body surface area (BSA) and height were used to index biventricular parameters. Parameters were compared between age groups and sex.

STATISTICAL TESTS

Independent-samples t-tests or Mann-Whitney U test to compare mean values between sexes; ANOVA or Kruskal-Wallis test to compare mean values among age groups; linear regression to assess the relationships between cardiac parameters and age (correlation coefficient, r). A P value <0.05 was considered statistically significant.

RESULTS

The biventricular volumes, LVM, LVEDD, RVEDV/LVEDV ratio, LVESD, AS, and PL were significantly greater in males than in females, even after indexing to BSA or height, while LVEF and RVEF were significantly lower in males than in females. For both sexes, age was significantly negatively correlated with biventricular volumes (male and female: LVEDV [r = -0.491; r = -0.373], LVESV [r = -0.194; r = -0.184], RVEDV [r = -0.639; r = -0.506], RVESV [r = -0.270; r = -0.223]), with similar correlations after BSA normalization. LVEF (r = 0.043) and RVEF (r = 0.033) showed a significant correlation with age in females, but not in males (P = 0.889; P = 0.282).

DATA CONCLUSION

MRI reference ranges for biventricular morphology and function in Chinese adults are presented and show significant associations with age and sex.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 2.

Healthy Adult Left and Right Ventricular Torsion and Torsion Rates With MR-Feature Tracking

BACKGROUND

The clinical value of myocardial torsion quantification in prognostic assessment and risk stratification of various cardiovascular diseases is gradually being recognized. However, normal values of left and right ventricular (LV and RV) torsion and torsion rates (TRs) have not been fully determined, and their correlation with age and gender has not been well studied.

PURPOSE

To establish normal ranges of biventricular torsion, peak systolic and diastolic TRs using magnetic resonance feature tracking (MR-FT) technique based on a large sample of healthy adults, and further investigate their relationship with age and gender.

STUDY TYPE

Retrospective.

POPULATION

566 Healthy adults (312 males, aged 43 ± 10 years; 254 females, aged 43 ± 11 years).

FIELD STRENGTH/SEQUENCE

1.5T/gradient echo.

ASSESSMENT

Biventricular torsion, peak systolic, and diastolic TRs.

STATISTICAL TESTS

Shapiro-Wilk test, Student's t-test, Mann-Whitney-U test, linear regression, intraclass correlation coefficient, Bland-Altman analysis. Differences were regarded as statistically significant at P < 0.05.

RESULTS

Women demonstrated greater magnitudes of left ventricle (LV) torsion (1.23 ± 0.44 vs. 1.00 ± 0.42°/cm), peak systolic TR (9.69 ± 3.70 vs. 8.27 ± 3.73°/cm*sec), peak diastolic TR (-7.78 ± 2.82 vs. -6.06 ± 2.44°/cm*sec), and RV torsion (2.20 ± 1.23 vs. 1.65 ± 1.11°/cm*sec), peak systolic TR (16.07 ± 8.18 vs. 12.62 ± 7.08°/cm*sec), peak diastolic TR (-15.39 ± 6.53 vs. -11.70 ± 6.03°/cm*sec). For both genders, the magnitudes of LV and RV torsion, peak systolic, and diastolic TRs increased linearly with age. All the measurements of biventricular torsion, peak systolic and diastolic TRs achieved good to excellent intraobserver and interobserver reproducibility, with all intraclass correlation coefficients >0.70.

DATA CONCLUSION

The present study systematically provided age- and sex-stratified reference values for LV and RV torsion and TRs using MR-FT technique. Women and aging are associated with greater magnitudes of biventricular torsion, peak systolic, and diastolic TRs.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Optimization of Intraventricular Radioactive Concentration for 13N ammonia PET with Time-of-Flight Scanner: Simplified Phantom Study with Noise Equivalent Count Rate Analysis

Background: Myocardial blood flow quantification (MBF) is one of the distinctive features for cardiac positron emission tomography. The MBF calculation is mostly obtained by estimating the input function from the time activity curve in dynamic scan. However, there is a substantial risk of count-loss because the high radioactivity pass through the left ventricular (LV) cavity within a short period. We aimed to determine the optimal intraventricular activity using the noise equivalent count rate (NECR) analysis with simplified phantom model. Methods: Positron emission tomography computed tomography scanner with LYSO crystal and time of flight was used for phantom study. 150 MBq/mL of 13N was filled in 10 mL of syringe, placed in neck phantom to imitate end-systolic small LV. 3D list-mode acquisition was repeatedly performed along radioactive decay. Net true and random count rate were calculated and compared to the theoretical activity in the syringe. NECR curve analysis was used to determine the optimal radioactive concentration. Result: The attenuation curves showed good correlation to the theoretical activity between 20 to 370, and 370 to 740 MBq (r2=1.0 ± 0.0001, p<0.0001; r2=0.99 ± 0.0001, p<0.0001 for 20 to 370, and 370 to 740, respectively), while did not over 740 MBq (p=0.62). NECR analysis revealed that the peak rate was at 2.9 Mcps, there at the true counts were significantly suppressed. The optimal radioactive concentration was determined as 36 MBq/mL. Conclusion: Simulative analysis for high-dose of 13N using the phantom imitating small LV confirmed that the risk of count-loss was increased. The result can be useful information in assessing the feasibility of MBF quantification in clinical routine.

Age- and sex-specific reference values of biventricular strain and strain rate derived from a large cohort of healthy Chinese adults: a cardiovascular magnetic resonance feature tracking study

BACKGROUND

As a noninvasive tool, myocardial deformation imaging may facilitate the early detection of cardiac dysfunction. However, normal reference ranges of myocardial strain and strain rate (SR) based on large-scale East Asian populations are still lacking. This study aimed to provide reference values of left ventricular (LV) and right ventricular (RV) strain and SR based on a large cohort of healthy Chinese adults using cardiovascular magnetic resonance (CMR) feature tracking (FT).

METHODS

Five hundred and sixty-six healthy Chinese adults (55.1% men) free of hypertension, diabetes, and obesity were included. On cine CMR, biventricular global radial, circumferential, and longitudinal strain (GRS, GCS, and GLS), and the peak radial, circumferential, and longitudinal systolic, and diastolic SRs (PSSRR, PSSRC, PSSRL, PDSRR, PDSRC, and PDSRL), and regional radial and circumferential strain at the basal, mid-cavity, and apical levels were measured. Associations of global and regional biventricular deformation indices with age and sex were investigated.

RESULTS

Women demonstrated greater magnitudes of LV GRS (37.6 ± 6.1% vs. 32.1 ± 5.3%), GCS (- 20.7 ± 1.9% vs. - 18.8 ± 1.9%), GLS (- 17.8 ± 1.8% vs. - 15.6 ± 1.8%), RV GRS (25.1 ± 7.8% vs. 22.1 ± 6.7%), GCS (- 14.4 ± 3.6% vs. - 13.2 ± 3.2%), GLS (- 22.4 ± 5.2% vs. - 20.2 ± 4.6%), and biventricular peak systolic and diastolic SR in all three coordinate directions (all P < 0.05). For the LV, aging was associated with increasing amplitudes of GRS, GCS, and decreasing amplitudes of PDSRR, PDSRC, PDSRL (all P < 0.05). For the RV, aging was associated with an increase in the magnitudes of GRS, GCS, GLS, PSSRR, PSSRC, PSSRL, and a decrease in the magnitude of PDSRR, PDSRC (all P < 0.05). Biventricular radial and circumferential strain measurements at the basal, mid-cavity, and apical levels were all significantly related to age and sex in both sexes (all P < 0.05).

CONCLUSIONS

We provide age- and sex-specific normal values of biventricular strain and SR based on a large sample of healthy Chinese adults with a broad age range. These results may be served as a reference standard for cardiac function assessment, especially for the Chinese population.