<p>Background Accurate and precise methods to predict growth remain lacking. Diffusion tensor imaging (DTI) depicts the columnar structure of the physis and metaphyseal spongiosa and provides measures of tract volume and length that may help predict growth. Purpose To validate physeal DTI metrics as predictors of height velocity (1-year height gain from time of MRI examination) and total height gain (height gain from time of MRI examination until growth stops) and compare the prediction accuracy with bone age-based models. Materials and Methods Femoral DTI studies ( values = 0 and 600 sec/mm; directions = 20) of healthy children who underwent MRI of the knee between February 2012 and December 2016 were retrospectively analyzed. Children with height measured at MRI and either 1 year later (height velocity) or after growth cessation (total height gain, mean = 34 months from MRI) were included. Physeal DTI tract volume and length were correlated with height velocity and total height gain. Multilinear regression was used to assess the potential of DTI metrics in the prediction of both parameters. Bland-Altman plots were used to compare root mean square error (RMSE) and bias in height prediction using DTI versus bone age methods. Results Eighty-nine children (mean age, 13 years ± 3 [SD]; 47 boys) had height velocity measured, and 70 (mean age, 14 years ± 1; 36 girls) had total height gain measured. Tract volumes correlated with height velocity ( = 0.49) and total height gain ( = 0.46) ( &lt; .001 for both) after controlling for age and sex. Tract volume was the strongest predictor for height velocity and total height gain. An optimal multilinear model including tract volume improved prediction of height velocity ( = 0.63, RMSE = 1.7 cm) and total height gain ( = 0.59, RMSE = 1.8 cm) compared with bone age-based methods (height velocity: = 0.32, RMSE = 2.9 cm; total height gain: = 0.42, RMSE = 5.0 cm). Conclusion Models using tract volume derived from diffusion tensor imaging may perform better than bone age-based models in children for the prediction of height velocity and total height gain. © RSNA, 2022.</p>

<p><strong>BACKGROUND: </strong>Survival from paediatric high-risk neuroblastoma (HR-NBL) has increased, but cis-retinoic acid (cis-RA), the cornerstone of HR-NBL therapy, can cause osteoporosis and premature physeal closure and is a potential threat to skeletal structure in HR-NBL survivors. Sarcopenia is associated with increased morbidity in survivors of paediatric malignancies. Low muscle mass may be associated with poor prognosis in HR-NBL patients but has not been studied in these survivors. The study objective was to assess bone density, body composition and muscle strength in HR-NBL survivors compared with controls.</p>

<p><strong>METHODS: </strong>This prospective cross-sectional study assessed areal bone mineral density (aBMD) of the whole body, lumbar spine, total hip, femoral neck, distal 1/3 and ultradistal radius and body composition (muscle and fat mass) using dual-energy X-ray absorptiometry (DXA) and lower leg muscle strength using a dynamometer. Measures expressed as sex-specific standard deviation scores (Z-scores) included aBMD (adjusted for height Z-score), bone mineral apparent density (BMAD), leg lean mass (adjusted for leg length), whole-body fat mass index (FMI) and ankle dorsiflexion peak torque adjusted for leg length (strength-Z). Muscle-specific force was assessed as strength relative to leg lean mass. Outcomes were compared between HR-NBL survivors and controls using Student's t-test or Mann-Whitney U test. Linear regression models examined correlations between DXA and dynamometer outcomes.</p>

<p><strong>RESULTS: </strong>We enrolled 20 survivors of HR-NBL treated with cis-RA [13 male; mean age: 12.4&nbsp;±&nbsp;1.6&nbsp;years; median (range) age at therapy initiation: 2.6 (0.3-9.1) years] and 20 age-, sex- and race-matched controls. Height-Z was significantly lower in HR-NBL survivors compared with controls (-1.73&nbsp;±&nbsp;1.38 vs. 0.34&nbsp;±&nbsp;1.12, P&nbsp;&lt;&nbsp;0.001). Areal BMD-Z, BMAD-Z, FMI-Z, visceral adipose tissue and subcutaneous adipose tissue were not significantly different in HR-NBL survivors compared with controls. Compared with controls, HR-NBL survivors had lower leg lean mass-Z (-1.46&nbsp;±&nbsp;1.35 vs. -&nbsp;0.17&nbsp;±&nbsp;0.84, P&nbsp;&lt;&nbsp;0.001) and strength-Z (-1.13&nbsp;±&nbsp;0.86 vs. -&nbsp;0.15&nbsp;±&nbsp;0.71, P&nbsp;&lt;&nbsp;0.001). Muscle-specific force was lower in HR-NBL survivors compared with controls (P&nbsp;&lt;&nbsp;0.05).</p>

<p><strong>CONCLUSIONS: </strong>Bone mineral density and adiposity are not severely impacted in HR-NBL survivors with growth failure, but significant sarcopenia persists years after treatment. Future studies are needed to determine if sarcopenia improves with muscle-specific interventions in this population of cancer survivors.</p>

<p><strong>BACKGROUND: </strong>Current methods to predict height and growth failure are imprecise. MRI measures of physeal cartilage are promising biomarkers for growth.</p>

<p><strong>PURPOSE: </strong>In the physis, to assess how 3D MRI volume measurements, and diffusion tensor imaging (DTI) measurements (tract volume and length) correlate with growth parameters and detect differences in growth. We compared patients exposed to cis-retinoic acid, which causes physeal damage and growth failure, with normal subjects.</p>

<p><strong>STUDY TYPE: </strong>Case-control.</p>

<p><strong>POPULATION: </strong>Twenty pediatric neuroblastoma survivors treated with cis-retinoic acid and 20 age- and sex-matched controls.</p>

<p><strong>FIELD STRENGTH/SEQUENCE: </strong>3T; DTI and 3D double-echo steady-state (DESS) sequences.</p>

<p><strong>ASSESSMENT: </strong>On distal femoral MR studies, physeal 3D volume and DTI tract measurements were calculated and compared to height.</p>

<p><strong>STATISTICAL TESTS: </strong>We used partial Spearman correlation, analysis of covariance, logistic regression, Wald test, and the intraclass correlation coefficient (ICC).</p>

<p><strong>RESULTS: </strong>The height percentile correlated most strongly with DTI tract volumes (r = 0.74), followed by mean tract length (r = 0.53) and 3D volume (r = 0.40) (all P &lt; 0.02). Only tract volumes and lengths correlated with annualized growth velocity. Relative to controls, patients showed smaller tract volumes (8.00 cc vs. 13.71 cc, P &lt; 0.01), shorter tract lengths (5.92 mm vs 6.99 mm, P = 0.03), and smaller ratios of 3D cartilage volume to tract length; but no difference (4.51 cc vs 4.85 cc) in 3D MRI volumes. The 10 patients with the lowest height percentiles had smaller tract volumes (5.07 cc vs. 10.93 cc, P &lt; 0.01), but not significantly different 3D MRI volumes. Tract volume is associated with abnormal growth, with an accuracy of 75%.</p>

<p><strong>DATA CONCLUSION: </strong>DTI tract volume of the physis/metaphysis predicts abnormal growth better than physeal cartilage volumetric measurement and correlates best with height percentile and growth velocity.</p>

<p><strong>EVIDENCE LEVEL: </strong>2 TECHNICAL EFFICACY: Stage 2.</p>

<p><strong>BACKGROUND: </strong>The survival of patients with high-risk neuroblastoma has increased with multimodal therapy, but most survivors demonstrate growth failure.</p>

<p><strong>OBJECTIVE: </strong>To assess physeal abnormalities in children with high-risk neuroblastoma in comparison to normal controls by using diffusion tensor imaging (DTI) of the distal femoral physis and adjacent metaphysis.</p>

<p><strong>MATERIALS AND METHODS: </strong>We prospectively obtained physeal DTI at 3.0&nbsp;T in 20 subjects (mean age: 12.4&nbsp;years, 7 females) with high-risk neuroblastoma treated with high-dose cis-retinoic acid, and 20 age- and gender-matched controls. We compared fractional anisotropy (FA), normalized tract volume (cm/cm) and tract concentration (tracts/cm) between the groups, in relation to height Z-score and response to growth hormone therapy. Tractography images were evaluated qualitatively.</p>

<p><strong>RESULTS: </strong>DTI parameters were significantly lower in high-risk neuroblastoma survivors compared to controls (P&lt;0.01), particularly if the patients were exposed to both cis-retinoic acid and total body irradiation (P&lt;0.05). For survivors and controls, DTI values were respectively [mean ± standard deviation]: tract concentration (tracts/cm), 23.2±14.7 and 36.7±10.5; normalized tract volume (cm/cm), 0.44±0.27 and 0.70±0.21, and FA, 0.22±0.05 and 0.26±0.02. High-risk neuroblastoma survivors responding to growth hormone compared to non-responders had higher FA (0.25±0.04 and 0.18±0.03, respectively, P=0.02), and tract concentration (tracts/cm) (31.4±13.7 and 14.8±7.9, respectively, P&lt;0.05). FA, normalized tract volume and tract concentration were linearly related to height Z-score (R&gt;0.31; P&lt;0.001). Qualitatively, tracts were nearly absent in all non-responders to growth hormone and abundant in all responders (P=0.02).</p>

<p><strong>CONCLUSION: </strong>DTI shows physeal abnormalities that correlate with short stature in high-risk neuroblastoma survivors and demonstrates response to growth hormone treatment.</p>

<p><strong>OBJECTIVE: </strong>To evaluate the distribution of enthesitis and the accuracy of physical examination with a dolorimeter for the detection of enthesitis in children, using ultrasound (US) assessment as the reference standard.</p>

<p><strong>METHODS: </strong>We performed a prospective cross-sectional study of 30 patients with enthesitis-related arthritis (ERA) and 30 control subjects. The following tendon insertion sites were assessed by standardized physical examination with a dolorimeter and US: common extensor on the lateral humeral epicondyle, common flexor on the medial humeral epicondyle, quadriceps at the superior patella, patellar ligament at the inferior patella, Achilles, and plantar fascia at the calcaneus.</p>

<p><strong>RESULTS: </strong>Abnormal findings on US were detected most commonly at the insertion of the quadriceps (30% [18 of 60 sites]), common extensor (12% [7 of 60]), and Achilles (10% [6 of 60]) tendons. The intrarater reliability of US (kappa statistic) was 0.78 (95% confidence interval [95% CI] 0.63-0.93), and the interrater reliability was 0.81 (95% CI 0.67-0.95). Tenderness as detected by standardized dolorimeter examination had poor positive predictive value for US-confirmed enthesitis. In comparison to controls, patients with ERA reported more pain and had lower pain thresholds at every site, including control sites (P &lt; 0.001 for all comparisons). The interrater reliability of dolorimeter examination for detection of enthesitis was low (κ = 0.49 [95% CI 0.33-0.65]).</p>

<p><strong>CONCLUSION: </strong>Compared to US, standardized dolorimeter examination for the detection of enthesitis in children has poor accuracy and reliability. The decreased pain threshold of ERA patients likely contributed to the limited accuracy of the physical examination findings. Further research regarding the utility of US for identifying enthesitis at diagnosis of juvenile idiopathic arthritis, accurately predicting disease progression, and guiding therapeutic decisions is warranted.</p>

<p><strong>BACKGROUND: </strong>Tendon insertion pathologies such as enthesitis and apophysitis in children can result from trauma, overuse syndrome and arthritis. Knowledge of the US appearance of normal joints by age might aid diagnosis of pathologies.</p>

<p><strong>OBJECTIVE: </strong>We describe the age-related sonographic features of the elbows, knees and feet in healthy children, providing a reference for the normal appearance of tendon insertions, apophyseal cartilage and bursae.</p>

<p><strong>MATERIALS AND METHODS: </strong>This is a prospective cross-sectional study of 30 healthy children. Children were grouped according to age: group 1 (4-9&nbsp;years, n = 11), group 2 (10-13&nbsp;years, n = 9) and group 3 (14-18&nbsp;years, n = 10). Children completed pain and function questionnaires and underwent a standardized joint examination by a pediatric rheumatologist. The common extensor, common flexor, quadriceps, patellar and Achilles tendons and plantar fascia insertions were evaluated with gray-scale and power Doppler ultrasound. The anterior elbow, suprapatellar and retrocalcaneal bursae were evaluated for fluid. We measured the apophyseal cartilage thickness at the enthesis. Correlation analyses examined associations between age and tendon thickness. We used ANOVA, with location as a repeated measure, to test for gender differences in cartilage thickness.</p>

<p><strong>RESULTS: </strong>Children had a median age of 12.4&nbsp;years and 55% were boys. All 360 entheses appeared normal on gray-scale imaging. There was a strong linear relationship between tendon thickness and age. Tendon vascularity was only present in young children (group 1), in 7/22 (32%) quadriceps tendons. Peri-tendinous power Doppler signal was seen at seven sites: two patellar, four quadriceps and one common flexor tendon, and all these children were in group 2. Suprapatellar bursal fluid &lt;3&nbsp;mm was detected in 9/60 (15%) knees. Of the children in group 1, boys had thicker apophyseal cartilage than girls at the medial epicondyle, patellar poles and os calcis (P &lt; 0.05).</p>

<p><strong>CONCLUSION: </strong>Tendon vascularity may be a normal finding in young children, and mild peri-tendinous vascularity is not uncommon in children 10-13&nbsp;years of age. Tendon thickness has a linear relationship with age; however cartilage thickness varies across sites and also differs as a function of gender.</p>