Soroosh Mahboubi

Height Adjustment in Assessing Dual Energy X- Ray Absorptiometry Measurements of Bone Mass and Density in Children

CONTEXT In children, bone mineral content (BMC) and bone mineral density (BMD) measurements by dual-energy x-ray absorptiometry (DXA) are affected by height status. No consensus exists on how to adjust BMC or BMD (BMC/BMD) measurements for short or tall stature. OBJECTIVE The aim of this study was to compare various methods to adjust BMC/BMD for height in healthy children. DESIGN Data from the Bone Mineral Density in Childhood Study (BMDCS) were used to develop adjustment methods that were validated using an independent cross-sectional sample of healthy children from the Reference Data Project (RDP). SETTING We conducted the study in five clinical centers in the United States. PARTICIPANTS We included 1546 BMDCS and 650 RDP participants (7 to 17 yr of age, 50% female). INTERVENTION No interventions were used. MAIN OUTCOME MEASURES We measured spine and whole body (WB) BMC and BMD Z-scores for age (BMC/BMD(age)), height age (BMC/BMD(height age)), height (BMC(height)), bone mineral apparent density (BMAD(age)), and height-for-age Z-score (HAZ) (BMC/BMD(haz)). RESULTS Spine and WB BMC/BMD(age)Z and BMAD(age)Z were positively (P < 0.005; r = 0.11 to 0.64) associated with HAZ. Spine BMD(haz) and BMC(haz)Z were not associated with HAZ; WB BMC(haz)Z was modestly associated with HAZ (r = 0.14; P = 0.0003). All other adjustment methods were negatively associated with HAZ (P < 0.005; r = -0.20 to -0.34). The deviation between adjusted and BMC/BMD(age) Z-scores was associated with age for most measures (P < 0.005) except for BMC/BMD(haz). CONCLUSIONS 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.

Revised Reference Curves for Bone Mineral Content and Areal Bone Mineral Density According to Age and Sex for Black and Non-Black Children: Results of the Bone Mineral Density in Childhood Study

CONTEXT Deficits in bone acquisition during growth may increase fracture risk. Assessment of bone health during childhood requires appropriate reference values relative to age, sex, and population ancestry to identify bone deficits. OBJECTIVE The objective of this study was to provide revised and extended reference curves for bone mineral content (BMC) and areal bone mineral density (aBMD) in children. DESIGN The Bone Mineral Density in Childhood Study was a multicenter longitudinal study with annual assessments for up to 7 yr. SETTING The study was conducted at five clinical centers in the United States. PARTICIPANTS Two thousand fourteen healthy children (992 males, 22% African-Americans) aged 5-23 yr participated in the study. INTERVENTION There were no interventions. MAIN OUTCOME MEASURES Reference percentiles for BMC and aBMD of the total body, lumbar spine, hip, and forearm were obtained using dual-energy x-ray absorptiometry for Black and non-Black children. Adjustment factors for height status were also calculated. RESULTS Extended reference curves for BMC and aBMD of the total body, total body less head, lumbar spine, total hip, femoral neck, and forearm for ages 5-20 yr were constructed relative to sex and age for Black and non-Black children. Curves are similar to those previously published for 7-17 year olds. BMC and aBMD values were greater for Black vs. non-Black children at all measurement sites. CONCLUSIONS 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.

Fibrodysplasia ossificans progressiva

Abstract 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 4 q 27–31.

Effect of Lateral Positioning on Upper Airway Size and Morphology in Sedated Children

Background:Lateral positioning decreases upper airway obstruction in paralyzed, anesthetized adults and in individuals with sleep apnea during sleep. The authors hypothesized that lateral positioning increases upper airway cross-sectional area and total upper airway volume when compared with the supine position in sedated, spontaneously breathing children. Methods:Children aged 2–12 yr requiring magnetic resonance imaging examination of the head or neck region using deep sedation with propofol were studied. Exclusion criteria included any type of anatomical or neurologic entity that could influence upper airway shape or size. T1 axial scans of the upper airway were obtained in the supine and lateral positions, with the head and neck axes maintained neutral. Using software based on fuzzy connectedness segmentation (3D-VIEWNIX; Medical Imaging Processing Group, University of Pennsylvania, Philadelphia, PA), the magnetic resonance images were processed and segmented to render a three-dimensional reconstruction of the upper airway. Total airway volumes and cross-sectional areas were computed between the nasal vomer and the vocal cords. Two-way paired t tests were used to compare airway sizes between supine and lateral positions. Results:Sixteen of 17 children analyzed had increases in upper airway total volume. The total airway volume (mean ± SD) was 6.0 ± 2.9 ml3 in the supine position and 8.7 ± 2.5 ml3 in the lateral position (P < 0.001). All noncartilaginous areas of the upper airway increased in area in the lateral compared with the supine position. The region between the tip of the epiglottis and vocal cords demonstrated the greatest relative percent change. Conclusions:The upper airway of a sedated, spontaneously breathing child widens in the lateral position. The region between the tip of the epiglottis and the vocal cords demonstrates the greatest relative percent increase in size.

Effective Radiation Dose from Radiologic Studies in Pediatric Trauma Patients

Evaluation of the pediatric trauma patient frequently requires radiologic studies. Although low-dose radiation from diagnostic radiology is considered safe, lifetime risks per unit dose of radiation are increased in children compared to adults. The total effective dose of radiation to a typical pediatric trauma patient is unknown. We sought to estimate the total effective dose of radiation related to the radiologic assessment of injured children admitted to a pediatric Level I trauma center. We reviewed the radiology records of all children admitted directly to a trauma center in 2002 and tabulated all plain films, computed tomograms, angiographic/fluoroscopic studies, and nuclear medicine studies. Using age-adjusted effective doses (which incorporate biologic effects of radiation), we computed each patient’s total effective dose of radiation. Of 506 admitted patients, 394 (78%) underwent at least one radiologic study. The mean total effective dose per patient was 14.9 mSv (median: 7.2 mSv; interquartile range: 2.2–27.4 mSv). On average, computed tomography accounted for 97.5% of total effective dose. Age and injury severity score did not predict total effective dose. We conclude that in pediatric trauma patients, the estimated total effective dose of radiation varied widely. Computed tomography contributed virtually the entire total effective dose. Regarding radiographic evaluation of pediatric trauma patients, the risks and benefits of current practices should continue to be evaluated critically, because lifetime risks associated with radiation exposure are inversely proportional to age at exposure.

Computed tomography in the evaluation of pediatric neck infections.

In children, infections involving both the superficial and deep neck spaces are common. Children so affected typically present with fever, neck mass, neck stiffness, and, occasionally, airway compromise. Radiologic modalities used in the evaluation of neck infections include plain lateral neck radiography, ultrasound, computed tomography, and magnetic resonance imaging. All these modalities have proved useful in the treatment of such infections, specifically the decision to perform incision and drainage. The charts of 66 patients—33 with superficial and 33 with deep neck infections—were analyzed with respect to symptoms, signs, computed tomography findings, and need for surgical intervention. Computed tomography was not particularly helpful in superficial neck infections with regard to the decision to perform surgical drainage; however, it did localize and demonstrate the extent of infection. In deep neck infections we found a 92% correlation between computed tomographic evidence of an abscess and surgical confirmation of one. Contrast-enhanced computed tomography remains an excellent tool in the treatment of neck infections in children.

Postoperative evaluation of pulmonary arteries in congenital heart surgery by magnetic resonance imaging: Comparison with echocardiography

Palliative and corrective operations for the treatment of cyanotic congenital heart disease frequently involve or potentially influence the size of the pulmonary arteries. Echocardiography and magnetic resonance imaging (MRI) are two noninvasive imaging techniques currently used to assess morphologic abnormalities of the pulmonary arteries. The purpose of this study was to evaluate the role of MRI in comparison with echocardiography for defining morphologic changes of the pulmonary arteries after congenital heart surgery. The MRI scans and echocardiograms of 33 patients with surgery involving or affecting the pulmonary arteries were compared. The pulmonary outflow tract, pulmonary confluence, right and left pulmonary arteries, and surgical shunts were separately evaluated. Cineangiography and surgical reports were used to confirm findings. MRI and echocardiography were equivalent for demonstrating abnormalities of the right ventricular outflow tract, main pulmonary artery, and a variety of pulmonary shunts. MRI was superior to echocardiography in demonstrating abnormalities of the right and left pulmonary arterial branches (p < 0.001). MRI is effective for monitoring pulmonary arterial status after surgery and is superior to echocardiography for the evaluation of the right and left pulmonary arteries.

The utility of the pelvic radiograph in the assessment of pediatric pelvic fractures.

BACKGROUND Computed tomographic (CT) scanning is sensitive in detecting pelvic fractures in the pediatric patient. Pelvic fractures in the pediatric population rarely require emergent intervention, thus providing time to obtain the optimal imaging study. The objective of this study was to compare pelvic radiographs and abdominal pelvic CT scans of all pediatric trauma patients with pelvic injury to determine the role of pelvic imaging in the immediate trauma resuscitation. METHODS A retrospective review was performed of pediatric patients (age < 18 years) with a pelvic fracture identified from the registry of a Level I pediatric trauma center for the period 1993 to 2001. Patients with a documented pelvic injury and both a pelvic CT scan and pelvic radiograph available for review were extracted for analysis. For this study, all films were re-reviewed by an attending pediatric radiologist, and the abnormalities were categorized by the area of injury. The data were comparatively analyzed according to the area of injury and the soft tissue findings. RESULTS For the 8-year period, 130 pediatric patients with a pelvic fracture were identified, including 103 patients with both a pelvic CT scan and radiographs. Of the 151 fractures identified by pelvic CT scan, 81 were also identified by the pelvic radiograph (54%). There were 38 soft tissue hematomas noted by pelvic CT scan and only 2 identified by the pelvic radiograph. The greatest discrepancy was noted in comparison of the sacral region (16 abnormal pelvic CT scans vs. 3 abnormal radiographs); the least discrepancy was noted in the evaluation of the hip (6 abnormal pelvic CT scans vs. 5 abnormal radiographs). CONCLUSION The pelvic radiograph lacked the sensitivity of the pelvic CT scan for detecting pelvic fractures in all anatomic areas evaluated. Pelvic CT scan also offers additional information regarding soft tissue injury not available on most pelvic radiographs. In the trauma patient that will undergo abdominopelvic CT scanning as part of the trauma evaluation, a pelvic radiograph may be superfluous. Screening pelvic radiography should be reserved for the rare unstable patient or the patient in whom an abdominopelvic CT scan is not otherwise indicated.

Malignant endobronchial lesions of adolescence

Rare primary endobronchial malignancies were diagnosed in four adolescents: atypical bronchial carcinoid, mucoepidermoid carcinoma, bronchogenic (squamous cell) carcinoma, and non-Hodgkins lymphoma. Metastatic disease was evident in each case. Three of the four patients died within one year of diagnosis. This paper describes each of these entities, illustrates their plain film and CT abnormalities (bronchial “cut-off”, hilar mass, local congestive edema, lobar collapse, hyperinflation), and discusses the utility of CT in their diagnosis.

CT diagnosis of rib anomalies, tumors, and infection in children

The computed tomography (CT) findings of 3 patients with Ewings sarcoma and 10 patients with a variety of benign rib lesions including osteomyelitis, hemangiomatosis, eosinophilic granuloma, aneurysmal bone cyst, neurofibromatosis, enchondroma, and Jarcho-Levin syndrome are presented. CT is of great value in demonstrating characteristic findings of several benign rib lesions. Also, CT accurately shows the destructive pattern of the rib lesion, the presence of pleural effusion, and the local spread of the soft tissue mass. When an aggressive rib lesion with pleural effusion is encountered in an infant or child, Ewings sarcoma must be excluded unless this lesion has characteristic radiographic findings and a strong clinical history that suggest another diagnosis. The CT findings and differential diagnosis of rib lesions are discussed. Three-dimensional CT well demonstrated the appearance of congenital rib anomalies.