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.

Measuring External Rotation of the Fibula and Fibular Length in Bilateral Computed Tomography Scans: How Reliable Is This Method?

OBJECTIVES

During ankle fracture surgery, goals include accurate reduction and fixation of the fibula regarding rotation and fibular length. Bilateral postoperative computed tomography (CT) can be performed to assess fibular rotation using the talar dome angle, and fibular length. The aim of this study was to compare side-to-side differences of the fibular rotation and fibular length using bilateral CT scans of uninjured ankles.

METHODS

DESIGN

Retrospective.

SETTING

Single center, Level I Academic Trauma Center.

PATIENT SELECTION CRITERIA

Patients with bilateral CT scans of uninjured ankles.

OUTCOME MEASURES AND COMPARISONS

External rotation using the Nault talar dome method and fibular length using the coronal method of Prior et al. The average, difference, and ratio (injured side/healthy side) and interobserver variability were calculated.

RESULTS

There were 83 patients included (166 ankles, mean age 47 years, 77.1% male). A random set of 66 ankles (33 CT scans) were used to measure interobserver variability. The mean degrees of external rotation ranged from 6.6 to 7.7, mean difference ranged from 1.4 to 3.4 degrees, mean ratio ranged from 1.1 to 1.5, and interobserver variability ranged from 0.27 to 0.65. For fibular length, the mean ranged from 24.6 to 25.8 mm, mean difference in fibular length ranged from 0.5 to 2.1 mm, mean ratio ranged from 1.0 to 1.1 mm, and interobserver variability ranged from 0.45 to 0.73.

CONCLUSIONS

Using bilateral ankle CT scans, mean differences in fibular rotation using the Nault talar dome method were 1.4-3.4 degrees. The distal fibular length had a mean difference between both sides of 0.5-2.1 mm. Although the intraclass correlation's were low, the interleg differences between patients were small, making them useful for clinical practice.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Unravelling the intricacies of left ventricular haemodynamic forces: age and gender-specific normative values assessed by cardiac MRI in healthy adults

AIMS

Haemodynamic forces (HDFs) provided a feasible method to early detect cardiac mechanical abnormalities by estimating the intraventricular pressure gradients. The novel advances in assessment of HDFs using routine cardiac magnetic resonance (CMR) cines shed new light on detection of preclinical dysfunction. However, definition of normal values for this new technique is the prerequisite for application in the clinic.

METHODS AND RESULTS

A total of 218 healthy volunteers [38.1 years ± 11.1; 111 male (50.9%)] were recruited and underwent CMR examinations with a 3.0T scanner. Balanced steady state free precession breath hold cine images were acquired, and HDF assessments were performed based on strain analysis. The normal values of longitudinal and transversal HDF strength [root mean square (RMS)] and ratio of transversal to longitudinal HDF were all evaluated in overall population as well as in both genders and in age-specific groups. The longitudinal RMS values (%) of HDFs were significantly higher in women (P < 0.05). Moreover, the HDF amplitudes significantly decreased with ageing in entire heartbeat, systole, diastole, systolic/diastolic transition, and diastolic deceleration, while increased in atrial thrust. In multivariable linear regression analysis, age, heart rate, and global longitudinal strain emerged as independent predictors of the amplitudes of longitudinal HDFs in entire heartbeat and systole, while left ventricular end-diastole volume index was also independently associated with longitudinal HDFs in diastole and diastolic deceleration (P < 0.05 for all).

CONCLUSION

Our study provided comprehensive normal values of HDF assessments using CMR as well as presented with specific age and sex stratification. HDF analyses can be performed with excellent intra- and inter-observer reproducibility.

Cardiac T1ρ Mapping Values Affected by Age and Sex in a Healthy Chinese Cohort

BACKGROUND

To facilitate the clinical use of cardiac T1ρ, it is important to understand the impact of age and sex on T1ρ values of the myocardium.

PURPOSE

To investigate the impact of age and gender on myocardial T1ρ values.

STUDY TYPE

Cross-sectional.

POPULATION

Two hundred ten healthy Han Chinese volunteers without cardiovascular risk factors (85 males, mean age 34.4 ± 12.5 years; 125 females, mean age 37.9 ± 14.8 years).

FIELD STRENGTH/SEQUENCE

1.5 T; T1ρ-prepared steady-state free precession (T1ρ mapping) sequence.

ASSESSMENT

Basal, mid, and apical short-axis left ventricular T1ρ maps were acquired. T1ρ maps acquired with spin-lock frequencies of 5 and 400 Hz were subtracted to create a myocardial fibrosis index (mFI) map. T1ρ and mFI values across different age decades, sex, and slice locations were compared.

STATISTICAL TESTS

Shapiro-Wilk test, Student's t test, Mann-Whitney U test, linear regression analysis, one-way analysis of variance and intraclass correlation coefficient.

SIGNIFICANCE

P value <0.05.

RESULTS

Women had significantly higher T1ρ and mFI values than men (50.3 ± 2.0 msec vs. 47.7 ± 2.4 msec and 4.7 ± 1.0 msec vs. 4.3 ± 1.1 msec, respectively). Additionally, in males and females combined, there was a significant positive but weak correlation between T1ρ values and age (r = 0.27), while no correlation was observed between the mFI values and age (P = 0.969).

DATA CONCLUSION

We report potential reference values for cardiac T1ρ by sex, age distribution, and slice location in a Chinese population. T1ρ was significantly correlated with age and sex, while mFI was only associated with sex.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 1.

Normative Reference Equations for Breathlessness Intensity during Incremental Cardiopulmonary Cycle Exercise Testing

Rationale: Cardiopulmonary exercise testing (CPET) is the gold standard to evaluate exertional breathlessness, a common and disabling symptom. However, the interpretation of breathlessness responses to CPET is limited by a scarcity of normative data. Objectives: We aimed to develop normative reference equations for breathlessness intensity (Borg 0-10 category ratio) response in men and women aged ⩾40 years during CPET, in relation to power output (watts), oxygen uptake, and minute ventilation. Methods: Analysis of ostensibly healthy people aged ⩾40 years undergoing symptom-limited incremental cycle CPET (10 W/min) in the CanCOLD (Canadian Cohort Obstructive Lung Disease) study. Participants had smoking histories <5 pack-years and normal lung function and exercise capacity. The probability of each Borg 0-10 category ratio breathlessness intensity rating by power output, oxygen uptake, and minute ventilation (as an absolute or a relative value [percentage of predicted maximum]) was predicted using ordinal multinomial logistic regression. Model performance was evaluated by fit, calibration, and discrimination (C statistic) and externally validated in an independent sample (n = 86) of healthy Canadian adults. Results: We included 156 participants (43% women) from CanCOLD; the mean age was 65 (range, 42-91) years, and the mean body mass index was 26.3 (standard deviation, 3.8) kg/m2. Reference equations were developed for women and men separately, accounting for age and/or body mass. Model performance was high across all equations, including in the validation sample (C statistic for men = 0.81-0.92, C statistic for women = 0.81-0.96). Conclusions: Normative reference equations are provided to compare exertional breathlessness intensity ratings among individuals or groups and to identify and quantify abnormal breathlessness responses (scores greater than the upper limit of normal) during CPET.

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.

Normalized Echocardiographic Values From Guideline-Directed Dedicated Views for Cardiac Dimensions and Left Ventricular Function

BACKGROUND

Continuous technologic development and updated recommendations for image acquisitions creates a need to update the current normal reference ranges for echocardiography. The best method of indexing cardiac volumes is unknown.

OBJECTIVES

The authors used 2- and 3-dimensional echocardiographic data from a large cohort of healthy individuals to provide updated normal reference data for dimensions and volumes of the cardiac chambers as well as central Doppler measurements.

METHODS

In the fourth wave of the HUNT (Trøndelag Health) study in Norway 2,462 individuals underwent comprehensive echocardiography. Of these, 1,412 (55.8% women) were classified as normal and formed the basis for updated normal reference ranges. Volumetric measures were indexed to body surface area and height in powers of 1 to 3.

RESULTS

Normal reference data for echocardiographic dimensions, volumes, and Doppler measurements were presented according to sex and age. Left ventricular ejection fraction had lower normal limits of 50.8% for women and 49.6% for men. According to sex-specific age groups, the upper normal limits for left atrial end-systolic volume indexed to body surface area ranged from 44 mL/m2 to 53 mL/m2, and the corresponding upper normal limit for right ventricular basal dimension ranged from 43 mm to 53 mm. Indexing to height raised to the power of 3 accounted for more of the variation between sexes than indexing to body surface area.

CONCLUSIONS

The authors present updated normal reference values for a wide range of echocardiographic measures of both left- and right-side ventricular and atrial size and function from a large healthy population with a wide age-span. The higher upper normal limits for left atrial volume and right ventricular dimension highlight the importance of updating reference ranges accordingly following refinement of echocardiographic methods.

Normal reference values for mitral annular plane systolic excursion by motion-mode and speckle tracking echocardiography: a prospective, multicentre, population-based study

AIMS

Mitral annular plane systolic excursion (MAPSE) is a simple and reliable index for evaluating left ventricular (LV) systolic function, particularly in patients with poor image quality; however, the lack of reference values limits its widespread use. This study aimed to establish the normal ranges for MAPSE measured using motion-mode (M-mode) and two-dimensional speckle tracking echocardiography (2D-STE) and to explore its principal determinants.

METHODS AND RESULTS

This multicentre, prospective, cross-sectional study included 1952 healthy participants [840 men (43%); age range, 18-80 years] from 55 centres. MAPSE was measured using M-mode echocardiography and 2D-STE. The results showed that women had a higher MAPSE than men and MAPSE decreased with age. The age- and sex-specific reference values for MAPSE were established for these two methods. Multiple linear regression analyses revealed that MAPSE on M-mode echocardiography correlated with age and MAPSE on 2D-STE with age, blood pressure (BP), heart rate, and LV volume. Moreover, MAPSE measured by 2D-STE correlated more strongly with global longitudinal strain compared with that measured using M-mode echocardiography.

CONCLUSION

Normal MAPSE reference values were established based on age and sex. BP, heart rate, and LV volume are potential factors that influence MAPSE and should be considered in clinical practice. Normal values are useful for evaluating LV longitudinal systolic function, especially in patients with poor image quality, and may further facilitate the use of MAPSE in routine assessments.

Establishing Sex-Dependent Reference Intervals for KL-6 in Danish Adults

Krebs von den Lungen-6 (KL-6) is a promising biomarker for the diagnosis and prognosis of interstitial lung disease. However, reference intervals in Northern Europeans remain to be established using a latex-particle-enhanced turbidimetric immunoassay. The participants were Danish blood donors subjected to strict health requirements. Analyses were performed using the Nanopia KL-6 reagent on the cobas 8000 module c502. Sex-partitioned reference intervals were determined using a parametric quantile approach according to the Clinical and Laboratory Standards Institute guideline EP28-A3c. The study included 240 participants-121 females and 119 males. The common reference interval was 59.4-398.5 U/mL (95% confidence intervals (CI) for the lower and upper limits were 47.3-71.9 and 369.5-430.1, respectively). For females, the reference interval was 56.8-324.0 U/mL (95% CIs for the lower and upper limits were 36.1-77.6 and 303.3-344.7, respectively). For males, the reference interval was 51.5-448.7 U/mL (95% CIs for the lower and upper limits were 32.8-71.2 and 397.3-508.1, respectively). These results emphasize the importance of sex partitioning when evaluating KL-6 reference intervals. The reference intervals increase the clinical applicability of the KL-6 biomarker and provide a basis for future scientific studies of its utility in patient management.

The Very Low IgE Producer: Allergology, Genetics, Immunodeficiencies, and Oncology

Opposite to other immunoglobulin (Ig) classes and subclasses, there is no consensus on the definition of normal levels of serum total IgE. However, longitudinal studies on birth cohorts produced growth charts of total IgE levels in helminth-free and never atopic children and defining the normal ranges of total serum IgE concentration at the individual, rather than population, level. Accordingly, very 'low IgE producers' (i.e., children whose tIgE level belong to the lowest percentiles) became atopic while keeping their total IgE levels in a range considered 'normal' if compared to the general age-matched population but 'abnormally high' if projected on the tIgE growth chart against the trajectory of that child's own percentile levels. In 'low IgE producers', the IgE-specific activity, i.e., the ratio between allergen-specific and total IgE, is more important than the absolute specific IgE levels to confirm causality between allergen exposure and allergic symptoms. Patients with allergic rhinitis or peanut anaphylaxis but low or undetectable allergen-specific IgE levels must therefore be reconsidered considering their total IgE levels. Low IgE producers have been also associated with common variable immunodeficiency, lung diseases, and malignancies. A few epidemiological studies have shown a higher risk of malignancies in very low IgE producers, leading to a debated hypothesis proposing a novel, evolutionistic-relevant function for IgE antibodies for antitumor immune surveillance.

Normal Values of 3D Right Ventricular Size and Function Measurements: Results of the World Alliance of Societies of Echocardiography Study

BACKGROUND

Normal values for 3D right ventricular (RV) size and function are not well established, as they originate from small studies that involved predominantly white North American and European populations, did not use RV-focused views and relied on older 3D RV analysis software . The World Alliance of Societies of Echocardiography (WASE) study was designed to generate reference ranges for normal subjects around the world. In this study, we sought to assess the world-wide capability of 3D imaging of the right ventricle and report size and function measurements, including their dependency on age, sex and ethnicity.

METHODS

Healthy subjects free of cardiac, pulmonary and renal disease were prospectively enrolled at 19 centers in 15 countries, including 6 continents. 3D wide-angle RV datasets were obtained and analyzed using dedicated RV software (Tomtec) to measure end-diastolic and end-systolic volumes (EDV, ESV), stroke volume (SV) and ejection fraction (EF). Results were categorized by sex, age (18-40, 41-65 and >65 years) and ethnicity.

RESULTS

Of the 2007 subjects with attempted 3D RV acquisitions, 1051 had adequate image quality for confident measurements. Upper and lower limits for BSA-indexed EDV (mL/m²) and ESV (mL/m²) and EF (%) were [48, 95], [19, 43] and [44, 58] for men and [42, 81], [16, 36] and [46, 61] for women. Men had significantly larger EDV, ESV and SV (even after BSA indexing) and lower EF than women (p<0.05). EDV and ESV did not show any meaningful differences between age groups. 3D RV volumes were smallest in Asians.

CONCLUSIONS

Reliability of 3D RV acquisition is low worldwide underscoring the importance for future improvements in imaging techniques. Sex and race must be taken into consideration in the assessment of both RV volumes and EF.

Normative values of the aortic valve area and Doppler measurements using two-dimensional transthoracic echocardiography: results from the Multicentre World Alliance of Societies of Echocardiography Study

AIMS

Aortic valve area (AVA) used for echocardiographic assessment of aortic stenosis (AS) has been traditionally interpreted independently of sex, age and race. As differences in normal values might impact clinical decision-making, we aimed to establish sex-, age- and race-specific normative values for AVA and Doppler parameters using data from the World Alliance Societies of Echocardiography (WASE) Study.

METHODS AND RESULTS

Two-dimensional transthoracic echocardiographic studies were obtained from 1903 healthy adult subjects (48% women). Measurements of the left ventricular outflow tract (LVOT) diameter and Doppler parameters, including AV and LVOT velocity time integrals (VTIs), AV mean pressure gradient, peak velocity, were obtained according to ASE/EACVI guidelines. AVA was calculated using the continuity equation. Compared with men, women had smaller LVOT diameters and AVA values, and higher AV peak velocities and mean gradients (all P < 0.05). LVOT and AV VTI were significantly higher in women (P < 0.05), and both parameters increased with age in both sexes. AVA differences persisted after indexing to body surface area. According to the current diagnostic criteria, 13.5% of women would have been considered to have mild AS and 1.4% moderate AS. LVOT diameter and AVA were lower in older subjects, both men and women, and were lower in Asians, compared with whites and blacks.

CONCLUSION

WASE data provide clinically relevant information about significant differences in normal AVA and Doppler parameters according to sex, age, and race. The implementation of this information into clinical practice should involve development of specific normative values for each ethnic group using standardized methodology.

Sex- and age-specific normal values for automated quantitative pixel-wise myocardial perfusion cardiovascular magnetic resonance

AIMS

Recently developed in-line automated cardiovascular magnetic resonance (CMR) myocardial perfusion mapping has been shown to be reproducible and comparable with positron emission tomography (PET), and can be easily integrated into clinical workflows. Bringing quantitative myocardial perfusion CMR into routine clinical care requires knowledge of sex- and age-specific normal values in order to define thresholds for disease detection. This study aimed to establish sex- and age-specific normal values for stress and rest CMR myocardial blood flow (MBF) in healthy volunteers.

METHODS AND RESULTS

A total of 151 healthy volunteers recruited from two centres underwent adenosine stress and rest myocardial perfusion CMR. In-line automatic reconstruction and post processing of perfusion data were implemented within the Gadgetron software framework, creating pixel-wise perfusion maps. Rest and stress MBF were measured, deriving myocardial perfusion reserve (MPR) and were subdivided by sex and age. Mean MBF in all subjects was 0.62 ± 0.13 mL/g/min at rest and 2.24 ± 0.53 mL/g/min during stress. Mean MPR was 3.74 ± 1.00. Compared with males, females had higher rest (0.69 ± 0.13 vs. 0.58 ± 0.12 mL/g/min, P < 0.01) and stress MBF (2.41 ± 0.47 vs. 2.13 ± 0.54 mL/g/min, P = 0.001). Stress MBF and MPR showed significant negative correlations with increasing age (r = -0.43, P < 0.001 and r = -0.34, P < 0.001, respectively).

CONCLUSION

Fully automated in-line CMR myocardial perfusion mapping produces similar normal values to the published CMR and PET literature. There is a significant increase in rest and stress MBF, but not MPR, in females and a reduction of stress MBF and MPR with advancing age, advocating the use of sex- and age-specific reference ranges for diagnostic use.

Pediatric Cardiac Magnetic Resonance Reference Values for Biventricular Volumes Derived From Different Contouring Techniques

BACKGROUND

Measurement of ventricular volumes and function using MRI is an important tool in pediatric congenital heart disease. However, normal values for children are sparce and analysis methods are inconsistent.

PURPOSE

To propose biventricular reference values in children for two MRI postprocessing (contouring) techniques.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 154 children from two institutions (13.9 ± 2.8 years; 101 male) that were referred for a clinical MRI study.

FIELD STRENGTH/SEQUENCE

1.5 T; balanced steady-state free precession (bSSFP) sequence.

ASSESSMENT

Left ventricular (LV) and right ventricular (RV) end-diastolic and end-systolic volumes (LVEDV, LVESV, RVEDV, RVESV) and end-diastolic and end-systolic myocardial mass (LVEDMM, LVESMM, RVEDMM, RVESMM) were measured from short-axis images using two contouring techniques: 1) papillary muscles, trabeculations and the moderator band were included in the ventricular blood volume and excluded from the myocardial mass, 2) papillary muscles, trabeculations and the moderator band were excluded from the ventricular volume and included in the ventricular mass.

STATISTICAL TESTS

Univariable and multivariable linear regression models were used to evaluate relationships between sex, weight, height, body surface area (BSA) and age and volumetric results. Reference graphs and tables were created with the LMS-method. Contouring techniques were compared by intraclass correlation, regression analysis and Bland-Altman plots. A P value < 0.05 was considered statistically significant.

RESULTS

Height and BSA were significantly associated with LVESV (method 1) and with LVEDV and RVEDV (method 2). LVESV (method 2), RVESV (both methods), RVEDV (method 1), and LVEDMM and RVEDMM (both methods), showed significant associations with height and weight. LVSV and RVSV (both methods) were significantly associated with BSA and weight. RVESV (method 1) was significantly associated with age. Gender showed significant associations for all parameters.

DATA CONCLUSION

The proposed pediatric reference values can be used in the diagnosis and follow-up of congenital or acquired heart disease and for research purposes.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Turning lung clearance index on its head. Reference data for SF6 multiple-breath washout derived ventilation distribution efficiency

Cystic fibrosis (CF) lung disease is characterized by increased ventilation inhomogeneity (VI), as measured by multiple-breath washout (MBW). Lung clearance index (LCI) is the most reported VI outcome. This study aimed to evaluate historically published reference equations for sulfur hexafluoride (SF6) MBW outcomes, to data collected using updated commercial SF6MBW equipment, and to produce device-specific equations if necessary. SF6MBW was performed in 327 healthy children aged 0.1-18.4 yr [151 (46%) girls], 191 (58.4%) <3 yr. z-Scores were calculated from published reference equations (FRC and LCI) and multivariate linear regression was performed to produce device-specific reference equations. Due to increasing residual standard deviations with increasing LCI values, investigation of methods for improvement were investigated, based on the relationship between VI and dead space ventilation (VD/VT; dead space volume/tidal volume) in a cohort of 59 healthy children, 26 children with CF (n = 138 test occasions), and 49 adults with lung disease. Historical SF6MBW reference equations were unsuitable for EXHALYZER D data. In contrast to LCI and log10(LCI), 1/LCI (ventilation distribution efficiency; VDE) was linearly related to VD/VT, with z-scores linearly related to its absolute values. Reference equations were reported for VDE and log10(FRC). Significant predictors for VDE and log10(FRC), respectively, were log10(age) and sex, and log10(height), sex, and posture. VDE is potentially a better index of VI than LCI, particularly in more advanced CF lung disease and also for longitudinal monitoring. Further confirmatory clinical studies, particularly longitudinal imaging studies of structural or ventilatory changes, are warranted.NEW & NOTEWORTHY Lung clearance index (LCI) is the most used outcome from the multiple-breath washout test. As known for decades, the LCI is not linearly related to dead space ventilation, giving difficulties interpreting changes over time and in clinical trials. We present a new and improved outcome based on LCI, the ventilation distribution efficiency (VDE), which solves this problem by being linearly related to dead space ventilation. A pediatric age range reference equation for VDE is presented.

Reference Intervals and Percentiles for Hematologic and Serum Biochemical Values in Captive Bred Rhesus (Macaca mulatta) and Cynomolgus Macaques (Macaca fascicularis)

Several physiological characteristics and housing conditions are known to affect hematologic and serum biochemical values in macaques. However, the studies that have been conducted either report values calculated based on a small number of animals, were designed specifically to document the effect of a particular condition on the normal range of hematologic and serum biochemical values, or used parametric assumptions to calculate hematologic and serum biochemical reference intervals. We conducted a retrospective longitudinal cohort study to estimate reference intervals for hematologic and serum biochemical values in clinically healthy macaques based on observed percentiles without parametric assumptions. Data were obtained as part of the Biomedical Primate Research Centre (Rijswijk, The Netherlands) health monitoring program between 2018 and 2021. In total, 4009 blood samples from 1475 macaques were analyzed with a maximum of one repeat per year per animal. Data were established by species, gender, age, weight-for-height indices, pregnancy, sedation protocol, and housing conditions. Most of the parameters profoundly affected just some hematologic and serum biochemical values. A significant glucose difference was observed between the ketamine and ketamine-medetomidine sedation protocols. The results emphasize the importance of establishing uniform experimental groups with validated animal husbandry and housing conditions to improve the reproducibility of the experiments.

The Population Comparison Index: An Intuitive Measure to Calibrate the Extent of Impairments in Patient Cohorts in Relation to Healthy and Diseased Populations

We assume that a specific health constraint, e.g., a certain aspect of bodily function or quality of life that is measured by a variable X, is absent (or irrelevant) in a healthy reference population (Ref0), and it is materially present and precisely measured in a diseased reference population (Ref1). We further assume that some amount of this constraint of interest is suspected to be present in a population under study (SP). In order to quantify this issue, we propose the introduction of an intuitive measure, the population comparison index (PCI), that relates the mean value of X in population SP to the mean values of X in populations Ref0 and Ref1. This measure is defined as PCI[X] = (mean[X|SP] - mean[X|Ref0])/(mean[X|Ref1] - mean[X|Ref0]) × 100[%], where mean[X|.] is the average value of X in the respective group of individuals. For interpretation, PCI[X] ≈ 0 indicates that the values of X in the population SP are similar to those in population Ref0, and hence, the impairment measured by X is not materially present in the individuals in population SP. On the other hand, PCI[X] ≈ 100 means that the individuals in SP exhibit values of X comparable to those occurring in Ref1, i.e., the constraint of interest is equally present in populations SP and Ref1. A value of 0 < PCI[X] < 100 indicates that a certain percentage of the constraint is present in SP, and it is more than in Ref0 but less than in Ref1. A value of PCI[X] > 100 means that population SP is even more affected by the constraint than population Ref1.

Normal Values of Distal Radioulnar Joint Kinematics during a Dynamic Press Test

Background  Measurement of in vivo distal radioulnar joint (DRUJ) pathomechanics during simple activities can represent the disability experienced by patients and may be useful in diagnostics of DRUJ instability. A first step is to describe the physiological normal limits for DRUJ kinematics in a reproducible and precise test setup, which was the aim of this study. Methods  DRUJ kinematics were evaluated in 33 participants with dynamic radiostereometry (RSA) while performing a standardized press test examination. AutoRSA software was used for image analyses. Computed tomography (CT) forearm bone models were generated, and standardized anatomical axes were applied to estimate kinematic outcomes including, DRUJ translation, DRUJ position ratio, and changes in ulnar variance. Repeatability of dynamic RSA press test double examinations was evaluated to estimate the precision and intraclass correlation coefficient (ICC) test-retest agreement. Results  The maximum force during the press test was 6.0 kg (95% confidence interval [CI]: 5.1-6.9), which resulted in 4.7 mm (95% CI: 4.2-5.1) DRUJ translation, DRUJ position ratio of 0.40 (95% CI: 0.33-0.44), and increase in ulnar variance of 1.1 mm (95% CI: 1.0-1.2). The mean maximum DRUJ translation leveled off after a 5 kg force application. The DRUJ translation ICC coefficient was 0.93 within a prediction interval of ± 0.53mm. Conclusions  This clinical study demonstrates the normal values of DRUJ kinematics and reports excellent agreement and high precision of the press tests examination using an automated noninvasive dynamic RSA imaging method based on patient-specific CT bone models. The next step is the application of the method in patients with arthroscopic verified triangular fibrocartilage complex injuries. Level of Evidence  This is a Level IV, case series study.

Comparing a knowledge-based 3D reconstruction algorithm to TomTec 3D echocardiogram algorithm in measuring left cardiac chamber volumes in the pediatric population

BACKGROUND

Three-dimensional echocardiography (3DE) is an emerging method for volumetric cardiac measurements; however, few vendor-neutral analysis packages exist. Ventripoint Medical System Plus (VMS3.0+) proprietary software utilizes a validated Magnetic resonance imaging (MRI) database of normal ventricular and atrial morphologies to calculate chamber volumes. This study aimed to compare left ventricular (LV) and atrial (LA) volumes obtained using VMS3.0+ to Tomtec echocardiography analysis software.

METHODS

Healthy controls (n = 98) aged 0-18 years were prospectively recruited and 3D DICOM datasets focused on the LV and LA acquired. LV and LA volumes and ejection fractions were measured using TomTec Image Arena 3D LV analysis package and using VMS3.0+. Pearson correlation coefficients, Bland-Altman's plots, and intraclass coefficients (ICC) were calculated, along with analysis time.

RESULTS

There was a very good correlation between Ventripoint Medical System (VMS) and Tomtec LV systolic (r²  = .88, ICC .89 [95% CI .81, .94]), and diastolic (r²  = .88, ICC .90 [95% CI .77, .95]) volumes, and between VMS and Tomtec LA diastolic (r²  = .75, ICC .89 [95% CI .81, .93]) and systolic (r²  = .88, ICC .91 [95% CI .78, .96]) volumes on linear regression models. Natural log transformations eliminated heteroscedasticity, and power transformations provided the best fit. The time (mins) to analyze volumes using VMS were less than using Tomtec (LV VMS 2.3 ± .5, Tomtec 3.3 ± .8, p < .001; LA: VMS 1.9 ± .4, Tomtec 3.4 ± 1.0, p < .001).

CONCLUSIONS

There was a very good correlation between knowledge-based (VMS3.0+) and 3D (Tomtec) algorithms when measuring 3D echocardiography-derived LA and LV volumes in pediatric patients. VMS was slightly faster than Tomtec in analyzing volumetric measurements.

Normal Values for Myocardial Work Indices Derived From Pressure-Strain Loop Analyses: From the CCHS

BACKGROUND

Pressure-strain loop analyses is a noninvasive technique capable of evaluating myocardial work. Reference values are needed to benchmark these myocardial work indices for clinical practice.

METHODS

Healthy participants from a general population study were used to establish reference values for global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) measured by pressure-strain loop analyses. The relation to age and sex was examined. We furthermore examined the proportion of abnormal work indices according to low, intermediate, and high cardiovascular risk by the Framingham risk score.

RESULTS

The healthy sample consisted of 1827 participants (median age, 45 years; 39% men). Lower reference values were GWI, 1576 mm Hg%; GCW, 1708 mm Hg%; and GWE, 93.0% and upper reference value for GWW was 159 mm Hg%. Women exhibited significantly higher GWI, GCW, and GWW and lower GWE. Sex significantly modified the association between all indices and age (P for interaction: 0.001 for GWI, 0.009 for GCW, 0.003 for GWW, and 0.009 for GWE). For men, only GCW increased with age, whereas the other indices did not change with age. For women, GCW increased linearly with increasing age, whereas GWI, GWW, and GWE changed in a curvilinear fashion with age such that GWI increased in younger participants, GWW increased in elderly, and GWE declined concordantly. Abnormalities in myocardial work indices became more frequent with increasing Framingham risk score category (abnormal GWI: 2% versus 4% versus 5%, P=0.001; abnormal GCW: 2% versus 3% versus 4%, P=0.006; abnormal GWW: 3% versus 6% versus 11%, P<0.001; abnormal GWE: 3% versus 4% versus 11%, P<0.001).

CONCLUSIONS

Myocardial work indices differ between sexes and change with age in a sex-dependent manner. Accordingly, we established age- and sex-specific reference values from a general population sample. Abnormal work indices become more frequent with higher clinical risk.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02993172.

Dynamic Mediolateral Patellar Translation Is a Sex- and Size-Independent Parameter of Adult Proximal Patellar Tracking Using Dynamic 3 Tesla Magnetic Resonance Imaging

PURPOSE

To provide normal values for physiological patellofemoral tracking in a representative group of healthy individuals, as well as sex differences, using real-time 3T-magnetic resonance imaging (MRI) and to test for the reliability of the presented technique.

METHODS

One hundred knees of healthy individuals with no history of patellofemoral symptoms were scanned with dynamic MRI sequences, during repetitive cycles of flexion (40°) and full extension. Within a 30-seconds time-frame, three simultaneous, transverse slices were acquired. Dynamic mediolateral patellar translation (dMPT) and dynamic patellar tilt (dPT) were measured on two occasions by two independent examiners. Common radiological parameters were measured using static MRI, and correlations were calculated.

RESULTS

100 knees (53 right, 47 left; age: 26.7 ± 4.4 years; BMI: 22.5 ± 3.1) of 57 individuals (27 females, 30 males) were included. Mean height was 170.1 ± 7.7 cm in women and 181.8 ± 6.4 cm in men. Average patella diameter was 37.9 ± 2.7 (95% CI 37.1-38.7) mm in women and 42.4 ± 3.2 (95% CI 41.5-43.3) mm in men. In females, the patellar diameters and intercondylar distances were significantly smaller than in males (P < .001). Radiological parameters for patellar maltracking were within the normal range. During the range of motion, mean dMPT was 1.7 ± 2.4 (95% CI .9-2.5) mm in females and 1.8 ± 2.7 (95% CI 1.1-2.6) mm in males (P = .766). Mean dPT was 1.3 ± 2.9° (95% CI .4-2.1°) in females and -0.2 ± 3.8° (95% CI -1.2-.9°) in males (P = .036). Neither dMPT nor dPT was correlated with height, BMI, or patellar diameter. Intercondylar distance correlated weakly with dPT (r = -.241; P = .041). Intra- and interrater reliability were excellent for dMPT and dPT.

CONCLUSION

Dynamic mediolateral patellar translation is a size- and sex-independent parameter for proximal patellar tracking. In healthy individuals without patellofemoral abnormalities normal dMPT proximal to the trochlea groove was 1.7 ± 2.5 (1.2-2.2) mm, independent of size or sex. Normal dPT showed a dependency on sex and was 1.3 ± 2.9 (.4-2.1)° in women and -0.2 ± 3.8 (-1.2-0.9)° in men.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Diaphragmatic excursion by ultrasound: reference values for the normal population; a cross-sectional study in Egypt

Background

Measurement of diaphragmatic motion by ultrasound is being utilized in different aspects of clinical practice. Defining reference values of the diaphragmatic excursion is important to identify those with diaphragmatic motion abnormalities. This study aimed to define the normal range of diaphragmatic motion (reference values) by Mmode ultrasound for the normal population.

Methods

Healthy volunteers were included in this study. Those with comorbidities, skeletal deformity, acute or chronic respiratory illness were excluded. Diaphragmatic ultrasound in the supine position was performed using a lowfrequency probe. The B-mode was applied for diaphragmatic identification, and the M-mode was employed for the recording of the amplitude of diaphragm contraction during quiet breathing, deep breathing and sniffing.

Results

The study included 757 healthy subjects [478 men (63.14%) and 279 women (36.86%)] with normal spirometry and negative history of previous or current respiratory illness. Their mean age and BMI were 45.17 ±14.84 years and 29.36±19.68 (kg/m²). The mean right hemidiaphragmatic excursion was 2.32±0.54, 5.54±1.26 and 2.90±0.63 for quiet breathing, deep breathing and sniffing, respectively, while the left hemidiaphragmatic excursion was 2.35±0.54, 5.30±1.21 and 2.97±0.56 cm for quiet breathing, deep breathing and sniffing, respectively. There was a statistically significant difference between right and left diaphragmatic excursion among all studied subjects. The ratio of right to left diaphragmatic excursion during quiet breathing was (1.009±0.19); maximum 181% and minimum 28%. Only 19 cases showed a right to left ratio of less than 50% (5 men and 14 women). The diaphragmatic excursion was higher in males than females. There was a significant difference in diaphragmatic excursion among age groups. Age, sex and BMI significantly affected the diaphragmatic motion.

Conclusions

Diaphragmatic excursion values presented in this study can be used as reference values to detect diaphragmatic dysfunction in clinical practice. Diaphragmatic motion is affected by several factors including age, sex and body mass index.

Global and Regional Gastric Emptying Parameters: Establishment of Reference Values and Comparison of Different Camera View Methods

PURPOSE OF THE STUDY

The purpose of the study is to establish the reference values of global and regional gastric emptying parameters (GEPs) using a standard vegetarian meal acceptable to the Indian population and compare the values derived on different camera view methods.

MATERIALS AND METHODS

Thirty-six consecutive healthy subjects with age ≥18 years underwent gastric emptying scintigraphy using anterior, posterior, and left anterior oblique (LAO) views. GEP was derived based on decay corrected counts in regions of interest defined on the whole and proximal stomach. Counts in the anterior and posterior view images were used to derive GEP based on geometric mean (GM) method. Comparison of GEP among different camera view methods was done with Friedman test and post hoc Wilcoxon signed-rank test after Bonferroni correction. Reference values were derived based on percentiles.

RESULTS

Rapid gastric emptying based on GM method was defined as percent retention <20% at 1 h while delayed emptying as percent retention >40% and >5% at 2 h and 4 h, respectively. The reference range of half-time of gastric emptying was 23-109 min. The reference value of intragastric meal distribution at time t = 0 was >64%, while the reference range of retention index was 0.7-1.3. Although the overall distribution of GEP derived on different camera view methods could be statistically significant (P < 1.00), the small differences in the derived reference values are likely to be of no clinical significance.

CONCLUSION

The reference values of GEPs established in this study can be generalized for the Indian population and may be applied to aid in clinical decision making. We recommend the GM method as the preferred method, although single view method (LAO preferred over anterior) can also be an acceptable alternative.

Sex, Age and Race Related Normal Values of Right Ventricular Diastolic Function Parameters: Data from the World Alliance of Societies of Echocardiography Study

BACKGROUND

Though the assessment of right ventricular (RV) diastolic function is feasible, it has garnered far less momentum for use compared to its left ventricular counterpart. The scarcity of data defining normative RV diastolic function and the fact that implications of RV diastolic dysfunction in different disease states on outcomes are less well known, both hinder integration into routine clinical assessment. We sought to establish normal values of RV diastolic parameters stratified by sex, age and race using data from the World Alliance of Societies of Echocardiography (WASE) Study.

METHODS

We analyzed a subset of 888 normal subjects from the WASE database, including measurements of tricuspid valve (TV) inflow E- and A-wave velocities, E-wave deceleration time, TV annular tissue Doppler e' and a' velocities. Additionally, right atrial (RA) maximal volume and RA peak reservoir strain were measured. Patients were grouped by age (<40, 41-65, >65 years), and stratified by sex and race. Differences were analyzed using unpaired t-tests.

RESULTS

When compared to men, women had significantly higher TV e', E-wave and A-wave velocities, though differences were modest. Increasing age was associated with stepwise lower TV E-wave, e' velocities and TV E/A, higher a' velocities and E/e' ratios. RA peak reservoir strain was also lower and RA ESV trended towards being smaller for older age groups. Asian subjects demonstrated significantly higher a' velocities, lower E-wave, smallest RA ESV and lowest RA peak strain values, compared to whites of both sexes.

CONCLUSIONS

This study provides normal values for parameters used in the assessment of RV diastolic function stratified by race, sex and age. Our results demonstrate significant differences in RV diastolic parameters between age groups, which manifest in both the individual parameters and composite ratios of TV inflow and annular velocities. While limited sex- and race-related differences were also noted, age appears to have the most significant impact on RV diastolic parameters. These findings may aid in refining the current normative values.

Values of left ventricular diastolic function assessed by left atrial volumes and Doppler echocardiography in healthy Angolans: Effect of age and gender: A pilot study

INTRODUCTION

Studies about the reference values of conventional and tissue Doppler echocardiography in African populations are limited.

OBJECTIVES

To evaluate the effect of aging and gender in left ventricular diastolic function assessed by conventional and tissue Doppler echocardiography in healthy Angolans.

METHODS

Cross-sectional study involving healthy adult participants attending a diagnostic center in Luanda, Angola. Two-dimensional transthoracic B-mode and Doppler echocardiography were performed according to the Guidelines of the American Society of Echocardiography and the European Association of Cardiovascular Imaging.

RESULTS

A total of 103 men (47.5%) (mean age: 39.5 ± 10.8) and 114 women (52.5%) (mean age: 43.0 ± 12.5 years) were included. Women were older (p = 0.025) and showed smaller body surface area (p < 0.001) than men. Mitral E velocity and E/e' ratio were higher in women than in men. While DT of mitral E velocity was longer in men than in women (p = 0.041), E velocity, E/A ratio, and average e' velocity showed a negative significant correlation with increasing age (r - 0.33; p ≤ 0.001; r - 0.48; p ≤ 0.001 and r - 0.41; p ≤ 0.0001, respectively). Conversely, A wave velocity showed a significant positive correlation with age (r 0.47; p < 0.001).

CONCLUSIONS

In a healthy Angolan adult population, the variables of left ventricular diastolic function declined with age, reflecting a normal aging process. This must be taken into account when assessing diastolic function at different age categories.

Is nuchal translucency measurement feasible in early pregnancy?

BACKGROUND

To investigate whether early nuchal translucency measurement at 7+0 to 9+0 weeks (NT7-9w) is feasible, obtain normal values for different crown-rump lengths (CRL) in the above weeks and create percentile tables.

METHODS

A prospective study was conducted in the Obstetrics and Gynecology Department of the University Hospital of Ioannina, including data from women with singleton pregnancies, examined in the early pregnancy unit between November 2010 and May 2015 at a CRL of 10-27 mm. The early pregnancy scan was performed vaginally, and the NT7-9w, CRL, fetal heart rate, and mean yolk sac diameter were measured. Demographic data, including body mass index and smoking, were recorded.

RESULTS

NT7-9w was measured successfully in 192 fetuses out of 210 (91.4 %), with a CRL ranging from 10-27 mm. The median maternal age was 31 (range 18-43) years, and the median CRL was 19.9 (range 10.0-27.0) mm. Considering the above measurements, we created normal values and percentiles tables of NT at 7+0 to 9+0 weeks in relation to the corresponding CRL measurement.

CONCLUSION

According to the literature, this is the first attempt to measure NT in such weeks of pregnancy. NT measurement as early as 7+0 to 9+0 is feasible and normal values can be created and correlated with CRL measurements. HIPPOKRATIA 2021, 25 (4):151-155.

Determination of Reference Values of the Masseter Muscle Stiffness in Healthy Adults Using Shear Wave Elastography

Shear wave elastography (SWE) is an objective and reliable method for the assessment of muscles and internal organs. Every organ exhibits its own stiffness characteristics and hence requires individual reference values. We aimed to determine the reference values of stiffness of the masseter muscle in healthy adult individuals using SWE. We analyzed the data of 140 participants (74 men, 66 women) with a median age of 50 years. The overall mean elasticity was 10.67 ± 1.77 kPa. The average values were lower by 2.25 kPa (9.15%) in women compared to men (9.48 ± 1.47 kPa vs. 11.73 ± 1.27 kPa; p < 0.0001). The values of stiffness increased with age, with a correlation coefficient of about 0.35 and a p < 0.0001. Age was a significant influencing factor of masseter muscle stiffness. The left and right masseters had similar stiffness. We conclude that stiffness values are significantly lower in women than in men with a difference of 9%. Age significantly influences the stiffness of masseter muscle, and the values of stiffness increase significantly with age, particularly in men. However, further studies are required to determine the precise ranges of stiffness accounting for age and sex in healthy subjects and people with disorders and conditions of the masticatory system.

Determinants of dynamic inspiratory muscle strength in healthy trained elderly

BACKGROUND

The S-Index assessed by means of electronic devices is a measure of Inspiratory Muscle Strength (IMS) that highly correlates with the maximal inspiratory pressure (MIP). The variables involved when using regression models for the prediction of IMS/MIP depend on both the sample characteristics and the device or protocol used. In light of the scarce information on the influence of physical activity (PA) on IMS in healthy older adults (OA), together with the incorporation of new assessment devices, the objectives of this research are: 1) to determine which factors influence the IMS in a group of trained OA, using a portable electronic device; and 2) to propose a regression model to improve its assessment and training.

METHODS

One hundred and fifty-nine individuals were assessed for body composition, lung capacity, IMS, and PA. A total of 92 individuals (72.73 ± 4.99 years) were considered for the final sample.

RESULTS

Using age, sex, and weight as control variables, forced expiratory volume in the first second (FEV₁) is the variable which is most likely to be included in the model (80%), without physical fitness appearing to be decisive. In the absence of spirometric variables, cardiorespiratory fitness (6MWT) takes on this role in a predictive model (16%).

CONCLUSIONS

This is the first study proposing IMS predictive formulas considering spirometry and/or physical fitness results for a Spanish, healthy, and trained OAs population. A predictive formula including also the spirometric variables (mainly the FEV₁) might better predict the inspiratory muscle strength. In addition, physical and respiratory functions confirm to be different, so it is necessary for the inspiratory muscles to be trained in a specific way.

Relationships of Reference Points, Planes and Skull Symmetry on Posterior-anterior Cephalograms in Healthy Young Adults

BACKGROUND

Radiological cephalometry is an important diagnostic tool for analyzing the shape and proportions of the skull. Standardized teleradiography of the skull in posterior-anterior (PA) projection provides orientation data on the symmetry and vertical relations of the skull. The comparison of individual findings with normal values places high demands on the selection of a control group. The aim of this study was to characterize a group to be used as a standard for cephalometric comparisons.

PATIENTS AND METHODS

PA teleradiographs of 23 healthy young adults were analyzed. Distances from reference measuring points to the median sagittal plane and the orbital horizontal plane were made. All individuals showed ideal occlusion. None of the participants had been subjected to orthodontic therapy or craniomaxillofacial surgery.

RESULTS

The measurement results showed a high degree of lateral symmetry of the skeletal reference points and planes. Comparison of the vertical reference lines confirmed the symmetrical constitution of the facial skeleton.

CONCLUSION

The study group is suitable for comparison with the cephalometric evaluations of other study groups.

Revising nerve conduction reference limits

INTRODUCTION/AIMS

Our electrodiagnostic laboratory uses reference limits (RL) that have been handed down for four decades. With changes in instrumentation and technique, we wish to know if our RL should be modified. It is also useful to have RL based on patient demographics.

METHODS

Latency and velocity data from motor nerve conduction studies of 740 adult patients studied over an 8 mo period were tabulated. RL were derived using both extrapolated reference value (ERef) and multi-variable extrapolated reference value (MeRef) methods.

RESULTS

Distal latency values showed a significant but weak correlation with age and/or height. ERef limits for the median and ulnar nerve latency (3.96 and 3.45 ms, respectively) were very similar to current laboratory limits (3.9 and 3.3 ms, respectively). ERef limits for the tibial and fibular nerve latency (5.1 and 4.95 ms, respectively) were slightly shorter. Ulnar velocity did not depend on age or height. The ERef limit was the same as our present laboratory limit (50 m/s). Median and tibial velocity limits decreased with age (R²  > 0.25). Fibular motor nerve conduction limits decreased with age and height (R²  = 0.39).

DISCUSSION

ERef and MeRef were useful to validate and revise our latency and velocity RL. We will use ERef limits for tibial and fibular latency. MeRef generated linear regression equations based on age and/or height will be used for conduction velocity analysis of median, fibular, and tibial nerves. This will increase the specificity of our values.

Reference Values for Ventricular Volumes and Pulmonary Artery Dimensions in Pediatric Patients with Transposition of the Great Arteries After Arterial Switch Operation

BACKGROUND

Pulmonary artery (PA) anatomy in patients with transposition of the great arteries (TGA) after arterial switch operation (ASO) with Lecompte manoeuvre is different compared to healthy subjects, and stenoses of the PA are common. Magnetic resonance imaging (MRI) is an excellent imaging modality to assess PA anatomy in TGA patients. However, disease-specific reference values for PA size are scarce.

PURPOSE

To establish disease-specific reference ranges for PA dimensions and for biventricular volumes and mass.

STUDY TYPE

Retrospective.

SUBJECTS

A total of 69 pediatric patients with TGA after ASO (median age 12.6 years; range 5-17.8 years; 13 females and 56 males).

FIELD STRENGTH/SEQUENCE

3.0 T, steady-state free precession (SSFP) and gradient echo cine sequences and four-dimensional time-resolved magnetic resonance angiography with keyhole.

ASSESSMENT

Right and left PA (RPA, LPA) were each measured at three locations during its course around the aorta. Ventricular volumes, mass, and ejection fraction were measured from a stack of short axis cine images.

STATISTICAL TESTS

The lambda-mu-sigma (LMS) method of Cole and Green, univariate and multivariate linear models, and t-test.

RESULTS

Centile graphs and tables for PA dimensions, biventricular volumes, mass, and ejection fraction were created. Univariate linear analysis showed significant associations (P < 0.05) between body surface area (BSA), height, and weight with systolic MPA and RPA diameter. In multivariate linear analysis, only BSA remained a strong predictor for main PA and RPA diameters. For biventricular volumes, the univariate linear model revealed a strong influence of BSA, height, weight, and age (all P < 0.05). On multivariate linear analysis, only body height remained associated.

DATA CONCLUSION

Uni- and multivariate linear analyses showed a strong association between BSA and PA diameters, as well as between height and biventricular volumes, and therefore, centile tables and graphs are presented accordingly. Our data may improve MR image interpretation and may serve as a reference in future studies.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY STAGE: 2.

Age- and sex-based normal values of layer-specific longitudinal and circumferential strain by speckle tracking echocardiography: the Copenhagen City Heart Study

AIMS

Technical advancements in 2D-speckle tracking echocardiography (2DSTE) have allowed for quantification of layer-specific global longitudinal strain (GLS) and circumferential strain (GCS) of the left ventricle (LV). The aim of this study was to establish age- and sex-based reference ranges of peak systolic layer-specific GLS and GCS and to assess normal values of regional strain.

METHODS AND RESULTS

We performed 2DSTE analysis of 1997 members of the general population from the fifth round of the Copenhagen City Heart Study, who were free of cardiovascular disease and risk factors. The mean age was 46 ± 16 years (range 21-97) and 62% were female. Mean values for peak systolic whole wall GLS (GLSWW.Sys), endomycardial (GLSEndo.Sys), and epimyocardial (GLSEpi.Sys) were 19.9 ± 2.1% (prediction interval [PI]: 15.8-24.0%), 23.5 ± 2.5% (PI: 18.6-28.4%), and 17.3 ± 1.9% (PI: 13.6-21.1%), respectively. Mean peak systolic whole wall GCS (GCSWW.Sys), was 21.6 ± 3.7% (PI: 14.3-28.9%), endomyocardial (GCSEndo.Sys) was 31.9 ± 4.7% (PI: 22.7-41.1%), and epimyocardial (GCSEpi.Sys) was 14.3 ± 3.8% (PI: 6.8-21.8%). A significant discrepancy in normal strain values between males and females was observed. Men had lower mean values and lower reference limits for all strain parameters. Furthermore, GLS and GCS changed differently with age in males and females. Finally, regional LS decreased from the apical to the basal LV region in both sexes, and regional CS varied significantly by LV segment.

CONCLUSION

In this study, we reported age- and sex-based reference ranges of layer-specific GLS and GCS. These reference ranges varied significantly with sex and age.

MeRef: Multivariable extrapolated reference values in motor nerve conduction studies

INTRODUCTION

In this study we describe a method called "multivariable extrapolated reference values" (MeRef) that derives reference values (RVs) using patient data and includes the dependence of these variables on multiple patient demographic variables, such as age and height.

METHODS

Computer simulations were used to generate "normal" and "patient" nerve conduction data. Median, ulnar, and tibial motor nerve conduction data from 500 patients studied were tabulated. Data were analyzed using the MeRef method.

RESULTS

The simulations showed great similarity between RVs obtained from MeRef of "patient" data and traditional analysis of "normal" data. In the real patient data, MeRef gave RVs as regression equations based on patient age and/or height.

DISCUSSION

MeRef can provide RVs by including patient demographic data and does not require subject grouping. It provides parameters of multivariable linear regression and standard deviation, and requires a few hundred patient studies to define reference values.

Quantitative magnetic resonance imaging measures of three-dimensional aortic morphology in healthy aging and hypertension

Automated segmentation of three-dimensional (3D) aortic magnetic resonance imaging (MRI) renders a possible retrospective selection of any location to perform quantification of aortic caliber perpendicular to its centerline and provides regional and global 3D biomarkers such as length, diameter, or volume. However, normative age-related values of such measures are still lacking. The aim of this study was to provide normal values for 3D aortic morphological measures and investigate their changes in aging and hypertension. This was a retrospective study, in which 119 healthy controls (HC: 48 ± 14 years, 61 men) and 82 hypertensive patients (HT: 60 ± 14 years, 43 men) were enrolled. 1.5 and 3 T/3D steady state free precession or spoiled gradient echo were used. Automated 3D aortic segmentation provided aortic length, diameter, volume for the ascending (AAo), and descending aorta (DAo), along with cross-sectional diameters at three aortic landmarks. Age, sex, body surface area (BSA), smoking, and blood pressures were recorded. Both groups were divided into two subgroups (≤50 years, >50 years). Statistical tests performed were linear regression for age-related normal values and confidence intervals, Wilcoxon rank sum test for differences between groups (HC or HT), and multivariate analysis to identify main determinants of aortic morphological changes. In HC, linear regression revealed an increase in the AAo (respectively DAo) length by 2.84 mm (7.78 mm), maximal diameter by 1.36 mm (1.29 mm), and volume by 4.28 ml (8.71 ml) per decade. AAo morphological measures were higher in HT patients than in HC both ≤50 years but did not reach statistical significance (length: +2 mm, p = 0.531; diameter: +1.4 mm, p = 0.2936; volume:+6.8 ml, p = 0.1857). However, length (+6 mm, p = 0.003), maximal diameter (+4 mm, p < 0.001) and volume (+12 ml, p < 0.001) were significantly higher in HT patients than in HC, both >50 years. In a multivariate analysis, age, sex, and BSA were the major determinants of aortic morphology, irrespective of the presence of hypertension. Global and segmental aortic length, volume, and diameters at specific landmarks were automatically measured from 3D MRI to serve as normative measures of 3D aortic morphology. Such indices increased significantly with age and hypertension among the elderly subjects. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY STAGE: 3.

Are ECG changes in heart-healthy individuals of various ages related to cardiac disease 20 years later?

BACKGROUND

This research study aimed at assessing the electrocardiographic (ECG) changes caused by ageing in a cohort of healthy subjects with normal echocardiographic examinations.

METHODS

A total of 219 healthy individuals (119 males and 100 females) were evaluated for possible arrhythmias with a standard 12-lead resting ECG and 24-h Holter ECG. As the recordings were performed between 1998 and 2000, a 20-year follow-up study was carried out by assessing the local medical records to investigate whether the subjects had experienced any cardiovascular health complications or disease since the baseline assessment.

RESULTS

Eighty-three subjects (45 males and 38 females) presented with pathological ECG findings at baseline. The most common finding on analysis of Holter ECG recordings was premature atrial contractions, and the most severe pathological finding was episodes of ventricular tachycardia (eight subjects). Regarding the analysis of the standard 12-lead ECG, the most common finding was left ventricular hypertrophy, and the most severe pathological findings were ST-T changes and prolongation of the QT interval. Despite other cardiac examinations performed on these patients showing normal results, in combination with a strict inclusion criterion, this study showed that 28% of all subjects had pathological resting 12-lead ECGs at rest and 35% had pathological heart rhythms when assessed by 24-h Holter ECG. At follow-up, 21% of females and 43% of males had presented with ECG abnormalities, and 30% of females and 36% of males had cardiovascular disease. There was hypertension in 45% of females and in 58% of males. However, no association was found between the follow-up findings and ECG changes seen at baseline.

CONCLUSION

Although most ECG changes found at baseline could be considered as a normal variation, they may progress to more severe heart complications as the subject ages. The results of this study also validate ECG findings of previous studies and underline that diagnostic criteria should be based on gender and age.

Normative Cardiopulmonary Exercise Test Responses at the Ventilatory Threshold in Canadian Adults 40 to 80 Years of Age

BACKGROUND

Physiologic and symptom responses at the ventilatory threshold (Tvent) during incremental cardiopulmonary exercise testing (CPET) can provide important prognostic information.

RESEARCH QUESTION

This study aimed to develop an updated normative reference set for physiologic and symptom responses at Tvent during cycle CPET (primary aim) and to evaluate previously recommended reference equations from a 1985 study for predicting Tvent responses (secondary aim).

STUDY DESIGN AND METHODS

Participants were adults 40 to 80 years of age who were free of clinically relevant disease from the Canadian Cohort Obstructive Lung Disease. Rate of oxygen consumption (V˙O₂) at Tvent was identified by two independent raters; physiologic and symptom responses corresponding to V˙O₂ at Tvent were identified by linear interpolation. Reference ranges (5th-95th percentiles) for responses at Tvent were calculated according to participant sex and age for 29 and eight variables, respectively. Prediction models were developed for nine variables (oxygen pulse, V˙O₂, rate of CO₂ production, minute ventilation, tidal volume, inspiratory capacity, end-inspiratory lung volume [in liters and as percentage of total lung capacity], and end-expiratory lung volume) using quantile regression, estimating the 5th (lower limit of normal), 50th (normal), and 95th (upper limit of normal) percentiles based on readily available participant characteristics. The two one-sided test of equivalence for paired samples evaluated the measured and 1985-predicted V˙O₂ at Tvent for equivalence.

RESULTS

Reference ranges and equations were developed based on 96 participants (49% men) with a mean ± SD age of 63 ± 9 years. Mean V˙O₂ at Tvent was 50% of measured V˙O₂ peak; the normal range was 33% to 66%. The 1985 reference equations overpredicted V˙O₂ at Tvent: mean difference in men, -0.17 L/min (95% CI, -0.25 to -0.09 L/min); mean difference in women, -0.19 L/min (95% CI, -0.27 to -0.12 L/min).

INTERPRETATION

A contemporary reference set of CPET responses at Tvent from Canadian adults 40 to 80 years of age is presented that differs from the previously recommended and often used reference set from 1985.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00920348; URL: www.clinicaltrials.gov.

Intra-abdominal Pressure Has a Good Predictive Power for 28-Day Mortality: A Prospective Observational Study Conducted in Critically Ill Children

Objective: Elevated intra-abdominal pressure (IAP) is associated with organ dysfunction in critically ill children. Thus far, the predictive value of IAP for mortality remains unknown. Moreover, only few studies determined normal IAP values in pediatric intensive care unit (PICU) children. This study aimed to determine the predictive value of IAP for mortality and calculate normal IAP values in PICU patients. Methods: This prospective observational study was conducted in two PICUs of two tertiary care university teaching hospitals. Patients admitted to the PICU between December 2013 and November 2015 were included. IAP was determined by bladder pressure measurements performed every 8 h until 48 h or until PICU discharge. All patients (except neonatal patients) aged ≤ 14 years who were admitted to the PICUs and had no history of chemical neuromuscular blockade use, neurogenic bladder, or bladder surgery were enrolled. Binary logistic regression was used to analyze the predictive value of IAP for 28-day mortality. Receiver operating characteristic curves were generated to evaluate the prediction effect of IAP. Results: Overall, 229 patients were enrolled. IAP (hazard ratio 1.09, 95% confidence interval [CI] 1.029-1.161, P = 0.004) and lactic acid (hazard ratio 3.04, 95% CI 1.769-5.21, P < 0.001) were independent predictors of 28-day mortality. Additionally, IAP had good predictive power for 28-day mortality, with an area under the curve of 0.74. The optimal cutoff point was 12.13 mmHg (sensitivity 0.58, specificity 0.80). The Youden index was 0.38.Furthermore, 111 (48.47%) patients without high-risk factors or clinical manifestations of IAH were analyzed to determine normal IAP values, which were 7.57 ± 2.85 mmHg (range, 1.98-13.16 mmHg). There were no significant differences in normal IAP values according to different diseases, sex, age, weight, or body mass index (BMI). Conclusions: IAP has good predictive power for 28-day mortality. The optimal IAP cutoff point is 12.13 mmHg. The IAP reference range is 2.0-13.2 mmHg, which was not associated with factors such as sex, age, weight, and BMI in PICU children. We recommend that IAP be included in critical illness scoring systems in the future. IAP >12.13 mmHg may be more suitable for IAH definition in PICU patients.

Center-edge angle values in healthy children between 5 and 14 years old in Turkey

OBJECTIVE

The aim of this study was to determine the center-edge angle (CEA) values according to age, gender and side in healthy children between 5 and 14 years old in Turkey and to find out the angular limit values for mild and severe dysplasia.

METHODS

The data pool that was gathered to investigate the frequency of hip dislocation in children between 6 months and 14 years old in Turkey was used. The data pool consists of pelvis and lower abdomen radiographs obtained for reasons other than hip dysplasia. Lower abdomen/pelvis radiographies of children between 5 and 14 years old were extracted from the data pool and were evaluated. Distribution of CEA values according to age, gender and side was examined. Measurements were performed by a single investigator on computer by using a standard method. Reliability of the measurements was tested by three different investigators on randomly selected films by using the standard method.

RESULTS

CEA values of 3192 hips of 1596 children, who had no hip pathology, were measured. Mean CEA value was found as 26.2°±5.5°. The mean CEA was 26.2°±5.3° in males (%54) and 26.2°±5.7° in females (%46) (p=0.224). Mean values for the right and left hips were 25.7°±5.4° and 26.6°±5.6°, respectively. CEA value of 449 (14%) hips of 333 (20.8%) children was at the limit of mild dysplasia and CEA value of 70 (2.2%) hips of 58 (3.6%) children was at the limit of severe dysplasia. CEA values had increased by age and mild and severe dysplasia limits were determined for every age group.

CONCLUSION

The mild and severe dysplasia values that are defined according to ages in Turkish population will guide the investigators in the diagnosis, follow-up and treatment planning of developmental dysplasia.

LEVEL OF EVIDENCE

Level IV, Diagnostic Study.

The value of bronchoalveolar lavage for discrimination between healthy and diseased individuals

BACKGROUND

Bronchoalveolar lavage (BAL) is standard diagnostic procedure. Procedural recommendations have been made by pneumological societies including normal values for interpretation of BAL cytology. These normal values derive from small studies in healthy volunteers and have never been analysed for their sensitivity and specificity.

OBJECTIVES

This study aims to analyse sensitivity and specificity of these normal values by assessing lavage cell composition in healthy and diseased individuals.

METHODS

More than 6000 BAL were retrospectively analysed for their cellular distribution including BALs of 250 healthy individuals. All BALs were obtained under similar conditions.

RESULTS

Bronchoalveolar lavage cytology of healthy individuals mirrors data from previous studies with smoking being the most important manipulator of BAL cytology. Analyses of proposed normal values demonstrate specificity between 80% and 95%, whereas sensitivity ranges between 35% and 65%. Using different mathematical models, a value summing up the differences to ATS-proposed normal values of the cytological pattern was found to best discriminate between healthy and diseased individuals with a sensitivity of nearly 60% with a predefined specificity of 95%.

CONCLUSION

In summary, our analysis confirmed prior results for healthy volunteers and enlarged these findings by analysing sensitivity and specificity of lavage results in an independent validation cohort of diseased individuals. Thereby, the study may influence the acceptance of BAL in the diagnostic workup of individuals with pulmonary diseases. Additionally, the study proposes a novel value that facilitates lavage interpretation and may therefore be useful in further studies.

Developing Normative Reference Values for Nerve Conduction Studies of Commonly Tested Nerves among a Sample Pakistani Population

Introduction:

Most neurophysiology departments around the world establish their own normative data. However, ethnic differences are not taken into account. Our aim was to establish normal nerve conduction studies (NCS) data for routinely tested nerves in individuals of Pakistani (South Asian) origin and to compare with Western published data.

Materials and Methods:

One hundred healthy adults’ nerves were assessed, using standardized techniques. Individuals were grouped into age groups. Gender differences were assessed.

Results:

Of the 100 volunteers, 49 were female and 51 were male. Their mean age was 39.8 years. Findings showed statistically significant prolongation of median distal motor latency (DML) and F-wave latency with age and reduction of median, ulnar, and sural sensory amplitudes as age increased. Gender differences showed consistent difference in the normal values for median, ulnar, and peroneal DMLs and respective F-wave latencies, which were significantly shorter in females. Sensory amplitudes of tested upper extremity nerves were significantly lower in males. Comparing with available data, our findings are similar to the Saudi population but significantly different from the American and multiethnic Malaysian populations. Pakistani individuals generally have significantly higher amplitudes and faster conduction velocities with similarities to South Asian studies.

Conclusions:

We recommend normative NCS parameters for commonly tested nerves for the Pakistani population, using standardized techniques to ensure highest quality testing and outcomes.

Liver Stiffness Measured by 2-Dimensional Shear Wave Elastography: Prospective Evaluation of Healthy Volunteers and Patients With Liver Cirrhosis

OBJECTIVES

We aimed to establish normal values for liver stiffness measurement, performed by 2-dimensional shear wave elastography (LOGIQ E9; GE Healthcare, Wauwatosa, WI), in healthy volunteers, patients with nonhepatic morbidities, and patients with histologically confirmed liver cirrhosis.

METHODS

A total of 175 participants were included between July 2016 and February 2018. Three cohorts were analyzed: healthy volunteers (n = 68), patients with healthy livers but nonhepatic morbidities (n = 57), and patients with liver cirrhosis (n = 50). Liver stiffness measurement was performed by 2 observers with different levels of experience to determine interobserver agreement.

RESULTS

Of the 175 participants included, 91 were male, and the mean age ± SD was 44.4 ± 19.4 years. The success rate for 175 liver stiffness measurements was 95.4%. The number of unsuccessful measurements was significantly higher in the liver cirrhosis cohort (P = .04). The interobserver agreement was excellent (intraclass correlation coefficient, 0.87). Liver stiffness in the healthy-liver patient cohort (4.93 ± 0.83 kPa) was not significantly different from that in the healthy-volunteer cohort (5.19 ± 1.03 kPa; P = .13). Apart from male sex in the healthy-volunteer cohort, age, body mass index, mild steatosis, and nonhepatic morbidities had no significant impact on liver stiffness. Liver stiffness values in participants without liver disease (healthy volunteers and healthy-liver patients; n = 125) ranged from 3.62 to 7.02 kPa (2.5th-97.5th percentiles). Notably, there was no overlap of liver stiffness measurements between the patients without liver disease and the cirrhosis cohort (13.29 ± 3.27 kPa [7.76-19.49 kPa]).

CONCLUSIONS

Liver stiffness values in healthy individuals vary widely and are not dependent on age, body mass index, or specific nonhepatic comorbidities. Liver stiffness values within the normal range can noninvasively rule out cirrhosis, as liver stiffness is significantly higher in cirrhotic patients (P < .001). Two-dimensional shear wave elastography has excellent interobserver agreement.

Normal values of distal radioulnar translation assessed by three-dimensional C-arm scans: a cadaveric study

We investigated whether mobile C-arm cone beam computer tomography (CBCT) could be used to measure radioulnar translation. The study was conducted on 31 Thiel-fixed intact cadaver arms. Three-dimensional scans of each wrist were carried out in pronation and supination. Four established measurement methods were used (radioulnar line, subluxation ratio, epicentre and radioulnar ratio methods) to measure radioulnar translation. The intraclass correlation coefficient for inter-observer and intra-observer reliability were excellent in three of four methods (>0.94). The reference ranges for physiological radioulnar translation were between -30% and 91% (radioulnar line method), -32% and 87% (subluxation ratio method), -40% and 23% (epicentre method), and 2% and 73% (radioulnar ratio method). Our results indicate that radioulnar translation in the distal radioulnar joint can be determined reliably using mobile C-arm CBCT. The normal values provide a basis for further experimental and clinical studies.

Reference range determination for imaging biomarkers: Myocardial T1

BACKGROUND

Imaging biomarkers, such as the T₁ relaxation time of the myocardium using MRI, can be valuable in cardiac medicine if they are properly validated. Consensus statements recommend that for myocardial T₁ , each investigator should establish a reference range.

PURPOSE

To describe a statistically valid method for determining and reporting the reference range in each center, which simultaneously minimizes the twin risks of undersampling, leading to a uselessly uncertain range, and oversampling, which exposes volunteers to unnecessary scanning and wastes resources.

STUDY TYPE

Cohort.

POPULATION

In all, 278 normal human subjects without cardiac disease from two cardiac MR centers.

FIELD STRENGTH/SEQUENCE

1.5 T and 3 T; Modified Look-Locker Inversion recovery sequence.

ASSESSMENT

The T₁ relaxation time was estimated from multiple samples of tissue magnetization after inversion. A valid method for calculating a reference range was used.

STATISTICAL TESTS

Shapiro-Wilk test for normality; Tukey robust approach for identification of outliers; reference range calculation with confidence intervals.

RESULTS

Reference ranges for measurement of myocardial T₁ were calculated, with confidence intervals, enabling comparison with clinically important differences. At 3 T: 1129 to 1301 msec at site 1 (n = 21) and 1160 to 1309 msec at site 2 (n = 59), and at 1.5 T at site 2: 933 to 1020 msec (male, n = 130) and 965 to 1054 msec (female, n = 68). The 3 T reference range from site 1 was successfully benchmarked against the 3 T reference range at site 2.

DATA CONCLUSION

Myocardial T₁ reference ranges can be properly characterized, enabling clinical comparison to a valid reference range with known confidence intervals, using methodology similar to that described in this report.

LEVEL OF EVIDENCE

3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:771-778.

Atrial and ventricular ejection force of the fetal heart: Which of the four chambers is the dominant?

Background/Aim:

This study aimed to measure and compare the ejection force of the cardiac chambers in healthy singleton fetuses and to investigate the relationship of ejection force of cardiac chambers with gestational age, fetal sex, and fetal heart rate.

Patients and Methods:

A prospective study was performed on 68 singleton fetuses with a gestational age of 17–34 weeks. Atrial and ventricular ejection force was measured. Measurements were repeated in 18 of the fetuses to assess intraobserver reliability.

Results:

The right atrium had the highest ejection force of all the cardiac chambers. Ejection force of both atria and ventricles increased with gestational age.

Conclusion:

The right atrium is the dominant chamber of the fetal heart in 17–34 weeks of gestation. Comparison of our values with previous studies indicates that left atrial ejection force almost doubles in the 1^st month after birth. This study highlights the crucial role of the right atrium in the fetal cardiac function during 17–34 weeks of gestation.

Quantification of urinary sodium concentrations in term infants

BACKGROUND

Infants with gastrointestinal conditions and poor weight gain are administered sodium supplementation based on urinary sodium concentrations. However, the reference range of urinary electrolytes is unknown. The aim of this study was to ascertain the normal values of urinary electrolytes in healthy, term infants. Secondary aims were to establish the relationship between urinary electrolytes with weight velocity and feeding practices.

METHODS

Healthy, term (≥37 weeks' gestation) infants were recruited. Parental questionnaires were completed before discharge and at six weeks. Electrolytes were quantified from a urine sample at six weeks. t-Tests and Mann-Whitney U tests were conducted for parametric and non-parametric electrolytes, respectively.

RESULTS

A total of 200 infants were recruited before discharge. Twenty-nine follow-up questionnaires and urine samples were returned (nine female; mean gestational age 39 + 6 weeks [SD 9.9 days]; mean birthweight 3350 g [SD 483 g]; 17 breastfed, nine formula and three mixed; mean change in Z score for weight -0.914 [SD 0.814]). Majority (25/29) of infants had urinary sodium <20 mmo/L. Change in Z score for weight was similar between infants with sodium <20 mmol/L and >20 mmol/L ( P = 0.78). All exclusively breastfed infants had sodium <20 mmol/L, however, not statistically dissimilar to formula-fed infants ( P = 0.27).

CONCLUSION

Most term infants in this study had urinary sodium values <20 mmol/L with no identified relationship to weight velocity. Lower concentrations of sodium could be not quantified reliably because of the limitations of the analytical method that were used. More evidence is required to identify candidates for sodium supplementation.

Cornea Thermography: Optimal Evaluation of the Outcome and the Resulting Reproducibility

Purpose

The aim of the study was to establish a standardized quantitative evaluation of corneal temperature (CT) that includes anchoring reference points in the topography and minimization of artifacts. We further investigated the distribution and the short- and long-term reproducibility of the CT values, as well as the influence of the core temperatures.

Methods

The CT values in both eyes of 40 healthy subjects were measured through thermography. These examinations took place over the course of four visits within 2 consecutive weeks. At each visit, the CTs were measured twice in both eyes with intervals of 15 minutes between measurements.

Results

CT values were not significantly different between the right and left eyes and their distribution was nearly normal. The CTs increased slightly when measured twice over the 15-minute intervals (short-term reproducibility) but remained stable over a period of 2 weeks (long-term reproducibility). In addition, the CT values depended on the core temperatures.

Conclusions

Ocular surface thermography is a fast and noninvasive examination. The methods of optimized and standardized evaluation of the CT values facilitate comparisons and follow-ups.

Translational Relevance

Thermography can be used clinically and scientifically only if both the measurement and its evaluation are efficient and standardized and if the outcomes are highly reproducible.

Normal Values of Corrected Heart-Rate Variability in 10-Second Electrocardiograms for All Ages

Purpose: Heart-rate variability (HRV) measured on standard 10-s electrocardiograms (ECGs) has been associated with increased risk of cardiac and all-cause mortality, but age- and sex-dependent normal values have not been established. Since heart rate strongly affects HRV, its effect should be taken into account. We determined a comprehensive set of normal values of heart-rate corrected HRV derived from 10-s ECGs for both children and adults, covering both sexes.

Methods: Five population studies in the Netherlands (Pediatric Normal ECG Study, Leiden University Einthoven Science Project, Prevention of Renal and Vascular End-stage Disease Study, Utrecht Health Project, Rotterdam Study) provided 10-s, 12-lead ECGs. ECGs were stored digitally and analyzed by well-validated analysis software. We included cardiologically healthy participants, 42% being men. Their ages ranged from 11 days to 91 years. After quality control, 13,943 ECGs were available. Heart-rate correction formulas were derived using an exponential model. Two time-domain HRV markers were analyzed: the corrected standard deviation of the normal-to-normal RR intervals (SDNNc) and corrected root mean square of successive RR-interval differences (RMSSDc).

Results: There was a considerable age effect. For both SDNNc and RMSSDc, the median and the lower limit of normal decreased steadily from birth until old age. The upper limit of normal decreased until the age of 60, but increased markedly after that age. Differences of the median were minimal between men and women.

Conclusion: We report the first comprehensive set of normal values for heart-rate corrected 10-s HRV, which can be of value in clinical practice and in further research.

Reference values for respiratory impedance measured by the forced oscillation technique in adult men and women

INTRODUCTION

The forced oscillation technique (FOT) is a particularly useful test of the mechanical properties of the respiratory system that has an increasingly important role in lung function laboratories. There is general agreement in the literature that the determination of reference values is of utmost importance in the clinical use of the FOT.

OBJECTIVE

Our aim was to present reference values for whole-breath FOT measurements, establish which anthropometric variables were more predictive of impedance parameters, and provide all the details to adequately adopt these reference equations in individual laboratories.

METHODS

We prospectively evaluated a randomly selected non-smoking sample of the adult Brazilian population (288 subjects, 144 males and 144 females aged 20-86 years). The volunteers were separated by sex and divided into six groups based on decade of age. Sex-specific linear prediction equations were developed by multiple regression analysis using age, body mass and height as explanatory variables.

RESULTS

Age introduced a slight, but significant, reduction of resistance in men (P < .001) and women (P < .001). In general, significantly higher values of resistance were observed in females (P < .0001). Among the anthropometric variables analyzed, height was the best predictor for all parameters studied.

CONCLUSION

This study provides an original frame of reference for the FOT in Brazilian males and females aged 20-86 years. Height was the best predictor of respiratory impedance parameters. Details contributing to an adequate adoption of these reference equations elsewhere by transference and verification are also provided.