Reference Values for Cardiac and Aortic Magnetic Resonance Imaging in Healthy, Young Caucasian Adults

Cardiovascular Magnetic Resonance Reference Ranges From the Healthy Hearts Consortium

BACKGROUND

The absence of population-stratified cardiovascular magnetic resonance (CMR) reference ranges from large cohorts is a major shortcoming for clinical care.

OBJECTIVES

This paper provides age-, sex-, and ethnicity-specific CMR reference ranges for atrial and ventricular metrics from the Healthy Hearts Consortium, an international collaborative comprising 9,088 CMR studies from verified healthy individuals, covering the complete adult age spectrum across both sexes, and with the highest ethnic diversity reported to date.

METHODS

CMR studies were analyzed using certified software with batch processing capability (cvi42, version 5.14 prototype, Circle Cardiovascular Imaging) by 2 expert readers. Three segmentation methods (smooth, papillary, anatomic) were used to contour the endocardial and epicardial borders of the ventricles and atria from long- and short-axis cine series. Clinically established ventricular and atrial metrics were extracted and stratified by age, sex, and ethnicity. Variations by segmentation method, scanner vendor, and magnet strength were examined. Reference ranges are reported as 95% prediction intervals.

RESULTS

The sample included 4,452 (49.0%) men and 4,636 (51.0%) women with average age of 61.1 ± 12.9 years (range: 18-83 years). Among these, 7,424 (81.7%) were from White, 510 (5.6%) South Asian, 478 (5.3%) mixed/other, 341 (3.7%) Black, and 335 (3.7%) Chinese ethnicities. Images were acquired using 1.5-T (n = 8,779; 96.6%) and 3.0-T (n = 309; 3.4%) scanners from Siemens (n = 8,299; 91.3%), Philips (n = 498; 5.5%), and GE (n = 291, 3.2%).

CONCLUSIONS

This work represents a resource with healthy CMR-derived volumetric reference ranges ready for clinical implementation.

Preclinical Aortic Atherosclerosis in Adolescents With Chronic Disease

Background

Adolescents with chronic disease are often exposed to inflammatory, metabolic, and hemodynamic risk factors for early atherosclerosis. Since postmortem studies have shown that atherogenesis starts in the aorta, the CDACD (Cardiovascular Disease in Adolescents with Chronic Disease) study investigated preclinical aortic atherosclerosis in these adolescents.

Methods and Results

The cross‐sectional CDACD study enrolled 114 adolescents 12 to 18 years old with chronic disorders including juvenile idiopathic arthritis, cystic fibrosis, obesity, corrected coarctation of the aorta, and healthy controls with a corrected atrial septal defect. Cardiovascular magnetic resonance was used to assess aortic pulse wave velocity and aortic wall thickness, as established aortic measures of preclinical atherosclerosis. Cardiovascular magnetic resonance showed a higher aortic pulse wave velocity, which reflects aortic stiffness, and higher aortic wall thickness in all adolescent chronic disease groups, compared with controls ( P <0.05). Age (β=0.253), heart rate (β=0.236), systolic blood pressure (β=−0.264), and diastolic blood pressure (β=0.365) were identified as significant predictors for aortic pulse wave velocity, using multivariable linear regression analysis. Aortic wall thickness was predicted by body mass index (β=0.248) and fasting glucose (β=0.242), next to aortic lumen area (β=0.340). Carotid intima‐media thickness was assessed using ultrasonography, and was only higher in adolescents with coarctation of the aorta, compared with controls ( P <0.001).

Conclusions

Adolescents with chronic disease showed enhanced aortic stiffness and wall thickness compared with controls. The enhanced aortic pulse wave velocity and aortic wall thickness in adolescents with chronic disease could indicate accelerated atherogenesis. Our findings underscore the importance of the aorta for assessment of early atherosclerosis, and the need for tailored cardiovascular follow‐up of children with chronic disease.

Vascular Ageing in Youth: A Call to Action

Extensive evidence shows that risk factors for cardiovascular disease (CVD) begin to develop early in life. Childhood obesity and elevated blood pressure (BP) have become overwhelmingly challenging, with 57% of today's children predicted to be obese by the age of 35 years, and global rates of hypertension in children and adolescents increasing by 75% from 2000 to 2015. Thus, there is an urgent need for tools that can assess early CVD risk in youth, which may lead to better risk stratification, preventative intervention, and personalised medicine. Vascular ageing (the deterioration in vascular structure and function) is a pivotal progenitor of health degeneration associated with elevated BP. Exposure to adverse environmental and genetic factors from fetal life promotes the development and accumulation of subclinical vascular changes that direct an individual towards a trajectory of early vascular ageing (EVA)-an independent predictor of target organ damage in the heart, brain, and kidneys. Therefore, characterising vascular ageing from youth may provide a window into cardiovascular risk later in life. However, vascular ageing measurements only have value when techniques are accurate/validated and when reliable thresholds are available for defining normal ranges and ranges that signal increased risk of disease. The aim of this paper is to summarise current evidence on the importance of vascular ageing assessment in youth and the impact of interventions to prevent or delay EVA, to highlight the need for standardisation and validation of measurement techniques in children and adolescents, and the importance of establishing reference values for vascular ageing measures in this population.

Age-related values of aortic pulse wave velocity in healthy subjects measured by Doppler echocardiography

Aortic pulse wave velocity (aPWV) is a measure of aortic stiffness, which is an indicator of vascular aging and prognostic marker for cardiovascular complications. aPWV can be measured with various methods, but with different reference values depending on the technique used. Therefore, we decided to evaluate age-related values of aPWV, measured by Doppler echocardiography. We included 134 healthy adults (mean age 44.1 ± 13.2 years, 54% of females) divided into five groups based on age decades (D1 21-30 years, n = 29; D2 31-40 years, n = 24; D3 41-50 years, n = 34; D4 51-60 years, n = 25; and D5 61-70 years, n = 22). With the use of a cardiac probe and ECG tracing, ten Doppler waveforms were sequentially recorded, first in the distal aortic arch, and than in the left external iliac artery. Transit time was measured as a delay of the foot of the Doppler waveform in the distal, relative to the proximal location. The distance was measured over the body surface. aPWV was calculated as distance/transit time. Median aPWV in the whole group was 5.05 m/s [4.55-5.99] and did not differ according to sex (females, 5.28 m/s [4.50-6.1] vs. males, 4.95 m/s [4.59-5.77], p = 0.46). Mean aPWV values with 95% confidence intervals (95% CI) for each decade were as follows: D1, 4.54 m/s (4.37-4.72), D2, 4.61 m/s (4.36-4.87), D3, 5.11 m/s (4.89-5.33), D4, 6.04 m/s (5.63-6.45), and D5, 6.77 m/s (6.35-7.19). We report age-related values of aPWV, in a healthy population, measured by Doppler echocardiography. This may be helpful in future research exploring the associations between aortic stiffness, cardiac function, and cardiovascular risk.

Reference ranges ("normal values") for cardiovascular magnetic resonance (CMR) in adults and children: 2020 update

Cardiovascular magnetic resonance (CMR) enables assessment and quantification of morphological and functional parameters of the heart, including chamber size and function, diameters of the aorta and pulmonary arteries, flow and myocardial relaxation times. Knowledge of reference ranges ("normal values") for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. Compared to the previous version of this review published in 2015, we present updated and expanded reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques. Further, databases and references for deep learning methods are included.

MRI-derived aortic characteristics after pregnancy: The AMBITYON study

OBJECTIVES

Pregnancy and pregnancy complications have been associated with increased arterial stiffness even at young age. In this study we assessed the impact of parity on CMR-derived aortic characteristics as early markers of atherosclerosis and arterial stiffness in healthy women between 25 and 35 years.

STUDY DESIGN

We studied 68 women who participated in the AMBITYON study, a prospective population-based cohort study for assessment of atherosclerotic burden by MRI and traditional CVD risk factors in healthy, young adults. Of these women, 40 (58.8%) were nulliparous, 13 (19.1%) were primiparous and 15 (22.1%) were multiparous.

MAIN OUTCOME MEASURES

Descending thoracic aortic wall thickness (AWT) and pulse wave velocity (PWV) were measured using 3.0T CMR.

RESULTS

AWT measurements were similar between nulliparous women and primi- or multiparous women (1.6 mm ± 0.2 mm vs. 1.6 mm ± 0.2 mm; p = 0.79). Correction for age and systolic blood pressure did not change these results. Applying percentile based cut-off values showed a non-significant increase in AWT in parous women. PWV measurements did not differ between nulliparous women and parous women (4.5 m/s ± 0.7 m/s vs. 4.5 m/s ± 0.8 m/s; p = 0.78). Correction for age and systolic blood pressure did not influence these results. Using percentile based cut-off values, showed an increasing likelihood of higher PWV-values in parous women, although not statistically significant.

CONCLUSIONS

Direct measurement of aortic AWT and PWV by CMR showed no difference between nulliparous and parous women, probably indicating limited effect of pregnancy on arterial stiffness and early markers of atherosclerosis.

TRIAL REGISTRATION

Netherlands Trial Register (NTR) number: 4742.

Circulating levels of P-selectin and E-selectin relate to cardiovascular magnetic resonance-derived aortic characteristics in young adults from the general population, a cross-sectional study

BACKGROUND

Although endothelial cell adhesion molecules (CAMs) are postulated to play a key role in early atherosclerosis, studies on endothelial CAMs are mainly pertained to middle-aged populations and populations with an unfavourable cardiovascular risk burden. Therefore, this study evaluated whether circulating endothelial CAMs are related to cardiovascular magnetic resonance imaging (CMR) derived indicators of arterial wall alterations in a random sample of young adults from the general population.

METHODS

This cross-sectional study is part of the general-population-based Atherosclerosis-Monitoring-and-Biomarker-measurements-In-The-YOuNg (AMBITYON) cohort study. In 131 adults (age: 25-35 years), demography, anthropometry and a lipid spectrum was acquired. Thoracic aortic wall area, wall thickness and pulse wave velocity (PWV) were measured using a 3 T CMR-system. From stored blood samples, four CAMs (E-selectin, P-selectin, vascular CAM-1 and intercellular CAM-1) were measured using dedicated methods. Linear mixed-effects regression analysis was used to evaluate the relation of these CAMs with the selected aortic characteristics.

RESULTS

Of the studied endothelial CAMs, P-selectin related to natural logarithm transformed aortic wall thickness (β = 0.18 mm/(μg/ml), [95% confidence interval: 0.04, 0.31], p = 0.01) whereas E-selectin related to natural logarithm transformed aortic PWV (β = 3.01 (m/s)/(μg/ml), [95% confidence interval: 0.08, 5.95], p = 0.04). Of note, VCAM-1 and ICAM-1 did not relate to the selected aortic characteristics.

CONCLUSIONS

In young adults from the general population, circulating P-selectin and E-selectin levels appear positively related to CMR-derived aortic wall thickness and PWV, possibly pointing towards atherogenic inflammatory arterial wall alterations inflicted by these CAMs already in young adulthood.

TRIAL REGISTRATION

Netherlands National Trial Register (NTR): NTR4742 , Registered 18 August 2014, retrospectively registered.

High-Risk Cardiovascular Conditions in Sports-Related Sudden Death: Prevalence in 5,169 Schoolchildren Screened via Cardiac Magnetic Resonance

Improving preparticipation screening of candidates for sports necessitates establishing the prevalence of high-risk cardiovascular conditions (hr-CVC) that predispose young people to sudden cardiac death (SCD). Our accurate, novel protocol chiefly involved the use of cardiac magnetic resonance (CMR) to estimate this prevalence. Middle and high school students from a general United States population were screened by means of questionnaires, resting electrocardiograms, and CMR to determine the prevalence of 3 types of hr-CVC: electrocardiographic abnormalities, cardiomyopathies, and anomalous coronary artery origin from the opposite sinus with intramural coronary course (ACAOS-IM). We examined the range of normal left ventricular size and function in the main study cohort (schoolchildren 11-14 yr old). We defined diagnostic criteria for hr-CVC and compared the cardiac measurements of these younger participants with those of older children whom we examined (age, 15-18 yr). From 5,169 completed diagnostic studies (mean participant age, 13.06 ± 1.78 yr), CMR results revealed 76 previously undiagnosed cases of hr-CVC (1.47% of the total cohort): 11 of dilated cardiomyopathy (14.5%), 3 of nonobstructive hypertrophic cardiomyopathy (3.9%), 23 ACAOS-IM cases (30.3%; 6 left-ACAOS and 17 right-ACAOS), 4 Wolff-Parkinson-White patterns (5.3%), 34 prolonged QT intervals (44.7%), and 1 Brugada pattern (1.3%). Cardiomyopathies were significantly more prevalent in the older children. Of note, we identified 959 cases (18.5%) of left ventricular noncompaction. If our estimate is accurate, only 1.47% of school-age sports participants will need focused secondary evaluations; the rest can probably be reassured about their cardiac health after one 30-minute screening study.

Prevalence and Distribution of Atherosclerosis in a Low- to Intermediate-Risk Population: Assessment with Whole-Body MR Angiography

Purpose To quantify the burden and distribution of asymptomatic atherosclerosis in a population with a low to intermediate risk of cardiovascular disease. Materials and Methods Between June 2008 and February 2013, 1528 participants with 10-year risk of cardiovascular disease less than 20% were prospectively enrolled. They underwent whole-body magnetic resonance (MR) angiography at 3.0 T by using a two-injection, four-station acquisition technique. Thirty-one arterial segments were scored according to maximum stenosis. Scores were summed and normalized for the number of assessable arterial segments to provide a standardized atheroma score (SAS). Multiple linear regression was performed to assess effects of risk factors on atheroma burden. Results A total of 1513 participants (577 [37.9%] men; median age, 53.5 years; range, 40-83 years) completed the study protocol. Among 46 903 potentially analyzable segments, 46 601 (99.4%) were interpretable. Among these, 2468 segments (5%) demonstrated stenoses, of which 1649 (3.5%) showed stenosis less than 50% and 484 (1.0%) showed stenosis greater than or equal to 50%. Vascular stenoses were distributed throughout the body with no localized distribution. Seven hundred forty-seven (49.4%) participants had at least one stenotic vessel, and 408 (27.0%) participants had multiple stenotic vessels. At multivariable linear regression, SAS correlated with age (B = 3.4; 95% confidence interval: 2.61, 4.20), heart rate (B = 1.23; 95% confidence interval: 0.51, 1.95), systolic blood pressure (B = 0.02; 95% confidence interval: 0.01, 0.03), smoking status (B = 0.79; 95% confidence interval: 0.44, 1.15), and socioeconomic status (B = -0.06; 95% confidence interval: -0.10, -0.02) (P < .01 for all). Conclusion Whole-body MR angiography identifies early vascular disease at a population level. Although disease prevalence is low on a per-vessel level, vascular disease is common on a per-participant level, even in this low- to intermediate-risk cohort. © RSNA, 2018 Online supplemental material is available for this article.

Sex, body mass index, and blood pressure are related to aortic characteristics in healthy, young adults using magnetic resonance vessel wall imaging: the AMBITYON study

Objectives

More detailed evaluation of atherosclerosis and its key determinants in young individuals is warranted to improve knowledge on the pathophysiology of its development and progression. This study evaluated associations of magnetic resonance imaging (MRI)-derived aortic wall area, wall thickness, and pulse wave velocity (PWV) with cardiovascular risk factors in asymptomatic, young adults.

Materials and methods

In 124 adults (age: 25–35 years) from the general population-based Atherosclerosis Monitoring and Biomarker Measurements in the Young study, demography, anthropometry, and blood samples were collected. The studied MRI-parameters were measured using a 3.0T MRI system. Relations between cardiovascular risk factors and aortic characteristics were assessed using multivariable linear regression analyses.

Results

Mean age was 31.8 years, 47.6% was male. Aortic wall area was positively associated with age [β = 0.01, (95% confidence interval (CI) 2.00 × 10⁻³, 0.02), p = 0.01] and BMI [β = 0.01, (0.01, 0.02), p = 0.003] and negatively associated with sex (reference: men) [β = −0.06, (−0.11, −0.01), p = 0.02]. Natural logarithm transformed (ln) aortic wall thickness was positively associated with BMI [β = 0.01, (1.00 × 10⁻³, 0.02), p = 0.02]. Ln aortic PWV was positively associated with 10 mmHg increment of SBP [β = 0.06, (0.03, 0.09), p < 0.001] and DBP [β = 0.06, (0.02, 0.09), p = 0.006]. No relations were observed for smoking and lipids.

Conclusions

Already in early adulthood, aortic wall geometry and stiffness vary by age, sex, BMI, and blood pressure.