Normal right and left ventricular volumes prospectively obtained from cardiovascular magnetic resonance in awake, healthy, 0- 12 year old children

Abstract

Introduction: Pediatric z scores are necessary to describe size and structure of the heart in growing children, however, development of an accurate z score calculator requires robust normal datasets, which are difficult to obtain with cardiovascular magnetic resonance (CMR) in children. Motion-corrected (MOCO) cines from re-binned, reconstructed real-time cine offer a free-breathing, rapid acquisition resulting in cines with high spatial and temporal resolution. In combination with child-friendly positioning and entertainment, MOCO cine technique allows for rapid cine volumetry in patients of all ages without sedation. Thus, our aim was to prospectively enroll normal infants and children birth-12 years for creation and validation of a z score calculator describing normal right ventricular (RV) and left ventricular (LV) size.

Methods: With IRB approval and consent/assent, 149 normal children successfully underwent a brief noncontrast CMR on a 1.5 T scanner including MOCO cines in the short axis, and RV and LV volumes were measured. 20% of scans were re-measured for interobserver variability analyses. A general linear modeling (GLM) framework was employed to identify and properly represent the relationship between CMR-based assessments and anthropometric data. Scatter plots of model fit and Akaike's information criteria (AIC) results were used to guide the choice among alternative models.

Results: A total of 149 subjects aged 22 days-12 years (average 5.1 ± 3.6 years), with body surface area (BSA) range 0.21-1.63 m2 (average 0.8 ± 0.35 m2) were scanned. All ICC values were > 95%, reflecting excellent agreement between raters. The model that provided the best fit of volume measure to the data included BSA with higher order effects and gender as independent variables. Compared with earlier z score models, there is important additional growth inflection in early toddlerhood with similar z score prediction in later childhood.

Conclusions: Free-breathing, MOCO cines allow for accurate, reliable RV and LV volumetry in a wide range of infants and children while awake. Equations predicting fit between LV and RV normal values and BSA are reported herein for purposes of creating z scores.

Trial registration: clinicaltrials.gov NCT02892136, Registered 7/21/2016.

Keywords: Motion correction cine; Pediatric cardiology; Volumetry; Z scores.

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1

Example of positioning approach for a infant subjects using the “feed and bundle” approach, and b young children using the parents’ arms encircling them underneath the coil

Fig. 2

Contours of the right ventricle (RV) and left ventricle (LV) at end-diastole (left panel) and end-systole (right panel) demonstrating contouring strategy. Papillary muscle and trabeculations are included in the blood pool by tracing the blood pool-endocardial border of each ventricle in both phases

Fig. 3

Flow diagram of enrollment for pediatric normal data project, noting exclusions where appropriate

Fig. 4

Bland-Altman analyses for each of the 5 measured endpoints (LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), LV mass, RV end-diastolic volume (RVEDV), RV end-systolic volume (RVESV) for each of the 3 observers (LO, RC, YL)

Fig. 5

Scatterplots of LVEDV, LVESV, LV mass, LVEF and LV cardiac output (LVCO) with sample best fit lines, and Z = + 2, Z = -2 lines for the enrolled pediatric normal cohort

Fig. 6

Scatterplots of RVEDV, RVESV, RVEF and RV cardiac output (RVCO) with sample best fit lines, and Z = + 2, Z = -2 lines for the enrolled pediatric normal cohort

Fig. 7

Graph depicting the relationship between the previously published Buechel z score equations (mean, +2SD, − 2SD) and our z score equations (mean, +2SD, − 2SD) for LVEDV vs. body surface area (BSA) and RVEDV vs. BSA