We provide here dual-energy x-ray absorptiometry reference data on a well-characterized cohort of 2012 children and adolescents. These reference curves provide the most robust reference values for the assessment and monitoring of bone health in children and adolescents in the literature to date.

Most methods to adjust BMC/BMD Z-scores for height were biased by age and/or HAZ. Adjustments using HAZ were least biased relative to HAZ and age and can be used to evaluate the effect of short or tall stature on BMC/BMD Z-scores.

Context: Low bone mass may increase risk of fracture. Several chronic medical conditions, medications, and lifestyle factors affect bone mineral accrual. Appropriate reference values are essential for identification of children with bone deficits.Objective: Our objective was to establish reference curves for bone mineral content (BMC) and density (BMD) in children. Design and Setting:The Bone Mineral Density in Childhood Study is an ongoing longitudinal study in which measurements are obtained annually at five clinical centers in the United States.Participants: Participants included 1554 healthy children (761 male, 793 female), ages 6 -16 yr, of all ethnicities. Main Outcome Measures:Scans of the whole body, lumbar spine, hip, and forearm were obtained using dual-energy x-ray absorptiometry. Percentile curves based on three annual measurements were generated using the LMS statistical procedure.Results: BMC of the whole body and lumbar spine and BMD of the whole body, lumbar spine, total hip, femoral neck, and forearm are given for specific percentiles by sex, age, and race (Black vs. nonBlack). BMC and BMD were higher for Blacks at all skeletal sites (P Ͻ 0.0001). BMC and BMD increased with age, and a plateau was not evident by age 16 (girls) or age 17 (boys). The variation in BMC and BMD also increased with age.Conclusions: Age-, race-, and sex-specific reference curves can be used to help identify children with bone deficits and for monitoring changes in bone in response to chronic diseases or therapies. (J Clin Endocrinol Metab

The anatomical relationships between lymphoid, bony, and other tissues affecting the shape of the upper airway in children with obstructive sleep apnea syndrome (OSAS) have not been established. We therefore compared the upper airway structure in 18 young children with OSAS (age 4.8 +/- 2.1 yr; 12 males and 6 females) and an apnea index of 4.3 +/- 3.9, with 18 matched control subjects (age, 4.9 +/- 2.0 yr; 12 males and 6 females). All subjects underwent magnetic resonance imaging under sedation. Axial and sagittal T1- and T2-weighted sequences were obtained. Images were analyzed with image-processing software to obtain linear, area, and volumetric measurements of the upper airway and the tissues comprising the airway. The volume of the upper airway was smaller in subjects with OSAS in comparison with control subjects (1.5 +/- 0.8 versus 2.5 +/- 1.2 cm(3); p < 0.005) and the adenoid and tonsils were larger (9.9 +/- 3.9 and 9.1 +/- 2.9 cm(3) versus 6.4 +/- 2.3 and 5.8 +/- 2.2 cm(3); p < 0.005 and p < 0.0005, respectively). Volumes of the mandible and tongue were similar in both groups; however, the soft palate was larger in subjects with OSAS (3.5 +/- 1.1 versus 2.7 +/- 1.2 cm(3); p < 0.05). We conclude that in children with moderate OSAS, the upper airway is restricted both by the adenoid and tonsils; however, the soft palate is also larger in this group, adding further restriction.

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare and disabling genetic disorder of connective tissue. The condition is characterized by congenital malformation of the great toes and by progressive heterotopic ossification of the tendons, ligaments, fasciae, and striated muscles. Fibrodysplasia ossificans progressiva occurs sporadically and is transmitted as a dominant trait with variable expression and complete penetrance. Reproductive fitness is low. There are fewer than 150 known patients with the disorder in the United States. A point prevalence of one affected patient in every 2 million of population has been observed. There is no sexual, racial, or ethnic predilection. The disease presents in early life; its course is unavoidably progressive. Most patients are confined to a wheelchair by the third decade of life and often succumb to pulmonary complications in the 5th/6th decade of life. At present there is no effective prevention or treatment. The recent discovery of overproduction of bone morphogenetic protein-4 in lesional cells and lymphocytic cells of affected patients provides a clue to both the underlying pathophysiology and potential therapy. The FOP gene has recently been mapped to human chromosome 4q 27-31.

Fetal chest masses had characteristic MR imaging appearances. MR imaging was accurate for distinguishing congenital diaphragmatic hernia from CCAM and was useful for less common diagnoses and determination of the origin of very large chest tumors. Prenatal diagnosis was changed in some patients owing to MR results and affected treatment and counseling of parents. MR imaging is a valuable adjunct to US for prenatal diagnosis of fetal chest masses.

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The distalmost location of the intussusception mass and presence of the dissecting sign on images obtained during contrast enema have a higher positive predictive value for failed reduction. Screening ultrasound decreases the number of unnecessary contrast enemas performed; however, classic pathologic lead points, such as Burkitt lymphoma and Meckel diverticulum, may be difficult to diagnose with the use of ultrasound. Laparotomy and laparoscopy are equally safe and efficacious in reducing intussusception, with the length of the hospital stay after laparoscopy significantly shorter than that noted after laparotomy. Most failed enema reductions are idiopathic, and pathologic lead points are noted in 25% of cases.