Cross-Sectional Area In Children Research Articles

Nerve ultrasound reference values in children and adolescents: Echogenicity and influence of anthropometric factors including hand volume.

Nerve cross-sectional area (CSA) reference values in high-resolution ultrasound for children and adolescents are influenced by demographic and anthropometric factors such as age, height and weight. The influence of hand volume as an additional morphometric factor was evaluated and nerve echogenicity was analyzed in a prospective cross-sectional study. CSA were measured in 30 healthy children and adolescents from 2 to 17years in the median, ulnar, radial, tibial, peroneal and sural nerves. Height, weight, age, handedness and gender were recorded, the volume of the hands was measured using the water displacement method. The intra-nerve CSA variability (INV), left/right ratios and absolute differences were calculated. Age groups were compared by the Kruskal-Wallis test. The influence of demographic factors was analyzed using Spearman correlation and multiple linear regression. Echogenicity and fraction of black were determined for each nerve segment. Nerve CSA values were consistently lower than those reported for adults and correlated in all measured nerve sites with age, height, weight and hand volume. Weight showed the highest correlation coefficient (R = .95) with the best fitting model predicting CSA. Correlation coefficients were higher in a linear than in a logarithmic model. Ratios were stable, the absolute differences increased with age and were significantly different between age groups. Most nerves showed a mixed or hypoechogenic pattern in echogenicity analysis, hyperechogenicity is less frequently observed. Nerve CSA in children and adolescents is lower than in adults and increases proportionally during growth with a constant INV and left/right ratio in different age groups. Weight and age are predominant anthropometric factors predicting nerve size. Hand volume is correlated with nerve size, but does not predict CSA independently. Echogenicity can provide additional information on nerve structure.

Effects of Local Warming on the Peripheral Vein Cross-Sectional Area in Children Under Sedation

PurposePeripheral venous catheterization is challenging in small children. The local warming technique has been used to increase the peripheral vein cross-sectional area (CSA) and improve the success rate. However, there is limited evidence on the effect of local warming on venous CSA in children under sedation. DesignA pilot randomized controlled trial. MethodsEligible children aged 1 to 4 years undergoing ambulatory surgery were enrolled. At the bedside in the ambulatory surgery center, they were routinely sedated with 1 mcg/kg of intranasal dexmedetomidine. Through a computer allocation program, children were randomized into either a control group or a local warming group. Cephalic vein and basilic vein at 1 cm proximal to cubital fossa were scanned with ultrasound to measure venous CSA. Children in the control group received no intervention; those in the local warming group had a prepared hot pack of ~40°C applied to the target area on the arm for 5 minutes. A second ultrasound measurement was undertaken in both groups. FindingsA total of 35 from 40 children were analyzed. Cephalic vein CSA and basilic vein CSA increased significantly vs the first measurement within the local warming group (P < .05 for both) but not in the control group (P > .05 for both). Cephalic vein CSA was significantly different between groups at the second measurement (P < .05) but not at the first measurement (P > .05). Basilic vein CSA was significantly different between groups neither at the first measurement nor at the second measurement (P > .05 for both). The application of local warming resulted in an average of 34% increase (from 4.1 to 5.5 mm2) in cephalic vein CSA and an average of 21% increase (from 4.8 to 5.8 mm2) in basilic vein CSA. ConclusionsThe application of local warming induced mild venodilation in cephalic vein with an increase in CSA by 34% and had little venodilation effect on the basilic vein with an increase in CSA by only 21%.

Nerve ultrasound in the assessment of cross-sectional area in healthy children

Introduction. Nerve ultrasound continues to progress due to improved technical equipment and knowledge, but so far not enough research has been done to determine the normative values of the cross-sectional area in children, and the obtained results differ between laboratories and researchers.Aim of the study. To determine the normative values of peripheral nerves» cross-sectional area in children 5–18 years old.Materials and methods. High resolution nerve ultrasound of brachial plexus, median, ulnar, radial, femoral, sciatic, tibial and peroneal nerves was performed in 30 children in real time. Nerve trunks were visualized throughout the limb from both sides. The cross-sectional area of the nerves was measured by a manual tracing method with the rounding of the hypoechogenic contours of the nerve trunk. Nerves’ crosssectional area was measured at distal and proximal sites. The obtained data were statistically processed using Excel and Statistica 10.Results. No bilateral cross-sectional area’s differences were found in children. Boys had significantly thicker nerves compared to girls, older age group (13–17 years old) compared to younger ones. There was a significant correlation between cross-sectional area of the median nerve at the level of the wrist, sciatic nerve and children’ height and weight.Conclusions. The normal values of cross-sectional area in children can be used in the practical work of a neurologists, neurophysiologists and ultrasound technicians.

MRI Measurement of Upper Cervical Spinal Cord Cross-Sectional Area in Children.

Neurological and neurodegenerative diseases can affect the spinal cord (SC) of pediatric patients. Magnetic resonance imaging (MRI) allows for in vivo quantification of SC atrophy via cross-sectional area (CSA). The study of CSA values in the general population is important to disentangle disease-related changes from intersubject variability. This study aimed at providing normative values for cervical CSA in children, extending our previous work performed with adults. Seventy-eight children (age 7-17 years) were selected from a Developmental Dyslexia study. All subjects underwent a 3T brain MRI session and any incidental findings were reported on the scans. A sagittal 1 mm3 3-dimensional T1 -weighted brain acquisition extended to the upper cervical cord was used to measure CSA at C2-C3, as well as spinal canal area and skull volume (V-scale). These three metrics were linearly fitted as a function of age to extract trends and percentage annual changes. Sex differences of CSA were assessed using least squares regression analyses, adjusting for age. We tested normalization strategies proven to be effective in reducing the intersubject variability of adults' CSA. CSA changed as a function of age at a faster rate when compared with skull volume (CSA: 1.82% increase, V-scale: .60% reduction). Sex had a statistically significant effect on CSA. Normalization methods based on canal area and skull volume reduced the CSA intersubject variability up to 16.84%. We present CSA normative values in a large cohort of children, reporting on sources of intersubject variability and how to reduce them applying normalization methods previously developed.

A novel approach using volumetric dynamic airway computed tomography to determine positive end-expiratory pressure (PEEP) settings to maintain airway patency in ventilated infants with bronchopulmonary dysplasia.

Positive end-expiratory pressure (PEEP) is a key mechanical ventilator setting in infants with bronchopulmonary dysplasia (BPD). Excessive PEEP can result in insufficient carbon dioxide elimination and lung damage, while insufficient PEEP can result in impaired gas exchange secondary to airway and alveolar collapse. Determining PEEP settings based on clinical parameters alone is challenging and variable. The purpose of this study was to describe our experience using dynamic airway CT to determine the lowest PEEP setting sufficient to maintain expiratory central airway patency of at least 50% of the inspiratory cross-sectional area in children with BPD requiring long-term ventilator support. We retrospectively identified all infants with BPD who underwent volumetric CT with a dynamic airway protocol for PEEP optimization from December 2014 through April 2019. Sixteen infants with BPD underwent 17 CT exams. Each CT exam consisted of acquisitions spanning the trachea and mainstem bronchi. We measured cross-sectional area of the trachea and mainstem bronchi and qualitatively assessed the amount of atelectasis. We documented changes in management as a result of the CT exam. The average effective dose was 0.1-0.8mSv/scan. Of 17 CT exams, PEEP was increased in 9, decreased in 3 and unchanged after 5 exams. Dynamic airway CT shows promise to assist the clinician in determining PEEP settings to maintain airway patency in infants with BPD requiring long-term ventilator support. Further evaluation of the impact of this maneuver on gas exchange, cardiac output and other physiological measures is needed.

Guideline Values for Minimum Nasal Cross-Sectional Area in Children.

The purpose was to determine age-specific values of the minimum cross-sectional area of the nasal airway in children without cleft lip or palate and to assess whether gender differences occur with growth in order to develop guidelines for assessment in children with clefts. All schoolchildren aged 8 to 17 years who met the research criteria were studied during rest breathing using the pressure-flow technique. The children came from a rural area of 3800 inhabitants. Consecutive age cohorts were used for comparisons. Nasal cross-sectional area increased in females from 0.38 cm2 in 8-year-olds to 0.58 cm2 in 17-year-olds. There was a decrease in size at ages 10 to 11 and 14 to 15 years. In males, the area increased from 0.40 to 0.68 cm2 and decreased slightly from 9 to 10 and 14 to 15 years. The annual changes were statistically significant in females between 8 and 9 and 11 to 13 years of age, and in males from 11 to 12, 13 to 14, and 15 to 17 years of age. Across gender, the only significant difference occurred at age 16. Our results indicate that the increase in nasal airway size is not consistent during growth. Nasal airway size showed almost equal values for both genders in young children but was systematically larger in boys from 14 years of age on. The results refer that by 17 years of age nasal airway may not have reached adult size in males.

Effects of the Trendelenburg Position and Positive End-Expiratory Pressure on the Internal Jugular Vein Cross-Sectional Area in Children With Simple Congenital Heart Defects.

Catheterization of the internal jugular vein (IJV) remains difficult in pediatric populations. Increasing the cross-sectional area (CSA) of the IJV facilitates cannulation and decreases complications. We aimed to evaluate the Trendelenburg position and the levels of positive end-expiratory pressure (PEEP) at which the maximum increase of CSA of the IJV occurred in children undergoing cardiac surgery.In this prospective study, the CSA of the right IJV was assessed using ultrasound in 47 anesthetized pediatric patients with simple congenital heart defects. The baseline CSA was obtained in response to a supine position with no PEEP and compared with 5 different randomly ordered maneuvers, that is, a PEEP of 5 and 10 cm H2O in a supine position and of 0, 5, and 10 cm H2O in a 10° Trendelenburg position. Hemodynamic variables, including blood pressure and heart rate, maximum and minimum diameters, and CSA, were measured.All maneuvers increased the CSA of the right IJV with respect to the control condition. In the supine position, the CSA was increased by 9.4% with a PEEP of 5 and by 19.5% with a PEEP of 10 cm H2O. The Trendelenburg tilt alone increased the CSA by 19.0%, and combining the 10° Trendelenburg with a 10 cm H2O PEEP resulted in the largest IJV CSA increase (33.3%) compared with the supine position with no PEEP. Meanwhile, vital signs remained relatively steady during the experiment.The application of the Trendelenburg position and a 10 cm H2O PEEP thus significantly increases the CSA of the right IJV, perhaps improving the chances of successful cannulation in pediatric patients with simple congenital heart defects.

Normative MDCT Cross-Sectional Data Estimation of Superior Vena Cava and Innominate Vein in Growing Children Using Age as a Predictor

This retrospective study aimed to determine the superior vena cava (SVC) and left innominate vein (INV) normative cross-sectional area in children noninvasively using age as a predictor and also to compare the correlation of the area measured with the diameter on multidetector computed tomography (MDCT). Analysis of the SVC-INV cross-sectional area was performed for 73 consecutive patients. The cross-sectional area of the SVC-INV was manually estimated. A regression analysis was performed for the cross-sectional area and age separately, and regression equations were compared. One-way analysis of variance (ANOVA) was performed to evaluate significant differences in the area means according to age groups. Regression analysis showed that age can be a predictor for the area of the SVC (50.6 mm(2) + 1.01 × age), te INV (48.3 mm(2) + 0.93 × age), and the left SVC-INV junction (47.2 mm(2) + 0.92 × age), with respective R(2) values of 93, 88 and 94%. The comparative evaluation of the cross-sectional area and the diameter measurement of SVC showed that the cross-sectional area was more closely associated with the increasing age of the cohort (R(2) of 68 vs. 61%) than the measured diameter. For a cohort of patients without congenital or acquired heart disease, MDCT can be used as a complementary test for a normative cross-sectional normogram area database of SVC-INV using age as a predictor.

Modified Differential Renal Function Measurement Revised by Renal Cross Sectional Area in Children with Ureteropelvic Junction Obstruction

PurposeDiuretic 99mTc-diethylenetriaminepentaacetic acid (Tc-DTPA) renal scans may show false-negative or false-positive results in children with ureteropelvic junction obstruction (UPJO). We evaluated whether modified differential renal function (DRF) revised by the renal cross-sectional area on imaging study may be a more valuable predictor than conventional DRF on a renal scan for deciding on a proper interventional time.Materials and MethodsBetween September 2001 and January 2008, we reviewed the diuretic renal scan results of 29 pediatric patients who underwent pyeloplasty due to unilateral UPJO. Diuretic renal scans using the standard 99mTc-DTPA protocol and imaging studies for renal unit measurement area were done. Conventional DRF measurement and modified calculation of DRF per unit area were done. Conventional DRF was classified into group I (below 40%) and group II (above 40%).ResultsThe mean age of all patients was 42.6±52.6 months (range, 3-198 months). The mean cross-sectional areas of the UPJO kidney and of the normal contralateral kidney were 62.1±29.2 cm2 and 41.3±22.5 cm2, respectively (p<0.01). The conventional and modified DRF of the UPJO kidney were 45.2±9.2% and 35.2±9.5%, respectively (p<0.01). Thirteen children (62%) in group II (n=21) were classified in group I by the modified DRF measurement.ConclusionsThe modified DRF measurement calculated according to cross-sectional area showed fewer false-negative results and may be a valuable method for deciding on pyeloplasty under equivocal circumstances.

Dorsiflexor muscle-group thickness in children with cerebral palsy: Relation to cross-sectional area

If the thickness and cross-sectional area of the dorsiflexor muscle group are related in children with cerebral palsy, measurements of muscle thickness may be used to monitor changes in muscle size due to training or immobilisation in these patients. We assessed the validity and reliability of measurements of dorsiflexor muscle-thickness using the cross-sectional area of the muscle group as the criterion-related muscle-size variable. Muscle thickness was measured using ultrasound, and cross-sectional area using MRI in nine children with spastic cerebral palsy (eight with hemiplegia). Test-retest reliability of the muscle-thickness measurements was assessed in six healthy subjects. All measurements were made on both legs at 35% lower leg length. In the children with cerebral palsy, dorsiflexor muscle-thickness and cross-sectional area were well correlated (r(2) = 0.778, P < 0.001), and the reliability of the muscle-thickness measurements was high in the healthy subjects (ICC(2.1) = 0.94, standard error of measurement = 0.04 cm). The dorsiflexor muscle-thickness was 22% less in the affected compared to the non-affected leg in children with hemiplegic cerebral palsy (P < 0.001). Accordingly, the dorsiflexor cross-sectional area was 32% less in the affected compared to the non-affected leg (P = 0.002). Measurements of dorsiflexor muscle-thickness can be reliably obtained, and they reflect dorsiflexor cross-sectional area in children with cerebral palsy.

Trendelenburg Position, Simulated Valsalva Maneuver, and Liver Compression Do Not Alter the Size of the Right Internal Jugular Vein in Patients with a Bidirectional Glenn Shunt

Ultrasound is increasingly used to facilitate right internal jugular vein (RIJV) cannulation in children. In children without cardiac disease, position changes and enhancement maneuvers increase RIJV cross-sectional area (CSA) and further facilitate cannulation. We investigated the effect of these maneuvers on RIJV CSA in children with a bidirectional Glenn (BDG) shunt presenting for a Fontan procedure. The CSA (cm(2)) of the RIJV in 21 children with a BDG shunt presenting for a Fontan procedure was assessed by ultrasonic planimetry (SonoSite). Two positions, supine (S) and 15 degrees Trendelenburg (T); and two enhancements maneuvers, manual liver compression (L) and a simulated Valsalva maneuver (V) were utilized in combination. Eight separate measurements (S, S + L, S + V, S + L + V, T, T + L, T + V, T + L + V) were made in each patient. Data were analyzed using one-way analysis of variance with repeated measures and with Tukey post hoc pairwise comparison analysis. No significant change in the RIJV CSA or % change in CSA from baseline (S) was observed. Position changes and enhancement maneuvers are unlikely to facilitate RIJV cannulation in BDG shunt patients presenting for Fontan procedure because these interventions do not increase RIJV CSA.

Classical Positioning Decreases Subclavian Vein Cross-Sectional Area in Children

Recommendations for subclavian vein catheter placement in children are extrapolated from adult experience. The purpose of this study was to determine the ideal body position to optimize the size of the subclavian vein in children for percutaneous catheter placement. Children underwent ultrasound imaging of the subclavian vein in four supine body positions: head in a neutral position with the chin midline (NL) and no shoulder roll (SR); head turned 90 degrees away (TA) and no SR; head NL with an SR; and head TA with an SR. The cross-sectional area (CSA) of the subclavian vein was calculated and statistical significance was determined using the Student's t test and the Wilcoxon signed rank test. Nine children participated in the study, with a mean age of 5.3 years. The CSA of the subclavian vein was 0.39 +/- 0.24 cm2 with the head NL and no SR, compared with 0.31 +/- 0.20 cm2 with the head TA or 0.32 +/- 0.23 cm2 with the head TA and SR. This represented a significant reduction in the CSA of the subclavian vein by 22% and 18%, respectively (p < 0.05). In children, the recommended maneuvers of turning the head or turning the head and placing a posterior shoulder roll significantly reduce the cross-sectional area of the subclavian vein. Maintaining the head in a normal position with the chin midline without a shoulder roll optimizes subclavian vein size. Positioning children in this manner may serve to reduce the morbidity associated with percutaneous subclavian vein cannulation.

Effects of age, gender, and body size on nasal cross-sectional area in children

The long-term goal of this research is to define the dimensions of nasal airway adequacy in children. Nasal airway size and variables associated with growth were assessed in 138 healthy children aged 7-15 years. The pressure-flow technique (Warren, 1984) was used to calculate the smallest cross-sectional area of the nasal airway. Mean nasal area was 0.38 +/- 0.12 cm2 for 7-9-year-olds, 0.40 +/- 0.13 cm2 for 10-12-year-olds, and 0.46 +/- 0.16 cm2 for 13-15-year-old children, the effect of age being statistically significant. Nasal airway size did not vary systematically with body size nor was there any clear difference between girls and boys. We conclude that age should always be considered when assessing the status of the nasal airway in children and adolescents.

Tracheal cross-sectional area in children: CT determination.

A computer method that calculates tracheal cross-sectional area by compensating for partial volume averaging was developed and validated in a study with phantoms. The program was then used to determine the tracheal cross-sectional area of 30 normal children who ranged in age from four months to 18 years. CT-derived cross sections were correlated with age, height, weight, and body-surface area, and they were compared with findings of published clinical and post-mortem studies. CT cross-sectional areas ranged from 20-275 mm2, varied by as much as 22% at the three different tracheal levels studied, and appeared to correlate most closely with body height. CT-derived tracheal cross-sectional areas are quite similar to those in published reports of postmortem and clinical studies. Measurement of tracheal cross section by CT may prove useful in quantitating tracheal compromise by intrinsic or extrinsic causes.