Bone mineral density in MPS IV A (Morquio syndrome type A).

Mucopolysaccharidosis IV A (MPS IV A), Morquio A, is caused by deficiency in lysosomal enzyme N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which is responsible for the catabolism of the glycosaminoglycans (GAGs) keratan sulfate (KS) and chondroitin 6-sulfate (C6S). Accumulation of GAGs results in disrupted cartilage formation and skeletal dysplasia. In this prospective cross-sectional study, bone mineral density (BMD) of the whole body (WB), lumbar spine (LS), and lateral distal femur (LDF) was acquired by dual-energy X-ray absorptiometry (DXA) on patients with MPS IV A. Functional abilities, medical history, Tanner score, and laboratory results were reviewed. Age and sex-matched norms were used to calculate Z-scores. Participants included 18 patients (13 females; 16 were unrelated) with a mean age of 21.4years (3.3 to 40.8years). While every patient was able to bear weight, 9 were full-time ambulators. Whole-body DXA could be obtained on only 6 patients (5 full-time ambulators) because of respiratory compromise caused by the position, presence of hardware, or positioning difficulties. Mean WB Z-score was -2.0 (range-0.3 to -4.1). Technical issues invalidating LS DXA in 8 patients included kyphosis at the thoracolumbar junction resulting in overlap of vertebrae in the posterior-anterior view. Mean LS BMD Z-score in full-time ambulators was -3.4 (range-1.6 to -5.0) and in the non-/partial ambulator was -4.0 (-3.7 to -4.2). Lateral distal femur BMD was acquired on every patient, and average Z-scores were -2 or less at all sites; full-time ambulators exhibited higher BMD. In conclusion, the LDF proved to be the most feasible site to measure in patients with MPS IV A. The higher LDF values in ambulators suggest this should be a consideration in promoting bone health for this group.

Common and expected postmortem CT observations involving the brain: mimics of antemortem pathology.

BACKGROUND AND PURPOSE: Postmortem imaging with CT or MR is emerging as an effective technique to augment forensic autopsy. Expected findings on postmortem imaging of the brain may mimic pathologic processes in the living brain, leading to potential misdiagnosis. The purpose of this study is to describe the array of CT findings that can be expected to be present within the brain after death. MATERIALS AND METHODS: A retrospective review was performed using an anonymized data base of 33 postmortem head CTs with no evidence of trauma to the face or scalp. Head CTs were assessed for 1) loss of gray-white differentiation, 2) effacement of the ventricles and cisterns, 3) postmortem intravascular blood distribution, 4) presence of intracranial or intravascular air, and 5) an irregular appearance of the falx. Imaging findings were correlated with autopsy findings. RESULTS: Visualization of the basal ganglia was noted in 30 (91%) subjects, and the cortical ribbon was appreciated in 14 (42%). The ventricles and cisterns were effaced in 19 (58%) cases. An "expected postmortem blood distribution" was seen in 27 (82%) instances. Intravascular air was present in 14 cases (42%). A "lumpy" falx was present in 20 cases (61%). In 4 cases of subdural or subarachnoid hemorrhage noted on autopsy, but not on CT, retrospective review confirmed that a true discrepancy between the radiology and pathology findings persisted. CONCLUSIONS: Recognition of expected postmortem patterns is required before pathology can be accurately diagnosed. A limitation of CT virtual autopsy is the possibility of missing small blood collections.

Imaging in the surgical management of developmental dislocation of the hip.

UNLABELLED: Although the use of ultrasound in the diagnosis and early treatment of developmental dysplasia of the hip (DDH) has reduced the number of patients diagnosed late and decreased the number of operative procedures, surgical treatment is still needed in some patients. Late cases continue to occur as a result of missing the screening examination, being normal at initial screening and missing followup. Dysplasia may persist despite appropriate nonoperative or operative treatment. Many of these patients subsequently undergo closed or open reduction and femoral or acetabular reconstruction. Ultrasound of the hips is generally used up to 6 or 8 months of age, during which time the hips are largely cartilaginous, and radiographs after that time when bony development is more complete. Options to supplement ultrasound and radiography include arthrography, computed tomography, and magnetic resonance imaging. Several advances have been made in the imaging of DDH and its complications including acetabular labral pathology and of femoroacetabular impingement (FAI). We review imaging techniques other than ultrasound used in the management of DDH. LEVEL OF EVIDENCE: Level V, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Infant shoulder sonography: technique, anatomy, and pathology.

BACKGROUND: In the infant, shoulder injury due to birth trauma and infection in joint and bone may be difficult to detect radiographically. Shoulder ultrasound provides a dynamic, noninvasive method of evaluation. OBJECTIVE: To develop a technique to evaluate the infant shoulder and to successfully demonstrate pathology. MATERIALS AND METHODS: Using a multiplanar, dynamic technique, 24 normal and 12 symptomatic infants (age range, 3 days to 9 months) were examined (49 shoulders). RESULTS: Sonographic findings were normal in 41 shoulders and abnormal in 8 shoulders. Abnormalities included subluxation, fracture, abnormal cartilage, soft-tissue mass, and inflammatory collections, including effusion. CONCLUSION: Ultrasound can be used successfully to evaluate the infant shoulder for instability, fracture, and infection.

Experimental epiphysiodesis: magnetic resonance imaging evaluation with histopathologic correlation.

We performed an experimental epiphysiodesis on the tibia in 16 immature New Zealand white rabbits. The purpose was to study the process of trauma-induced growth plate closure. The animals were killed at weekly intervals over 8 weeks. We correlated the histological findings with serial magnetic resonance images. The undamaged, central part of the growth plate became histologically abnormal within 1 week. Mature bone bridge formation in the area of the epiphysiodesis was seen after 3 to 4 weeks. The study suggests that growth arrest starts before the bone bridge formation. Factors regulating cartilage growth may also play a role.

Ultrasonographic evaluation of hip morphology in osteochondrodysplasias.

The developing hip in children with osteochondrodysplasias has not been well-described because of delayed ossification and limitations of conventional radiologic techniques. Twenty-four children with various osteochondrodysplasias were evaluated by ultrasonography. Variation in the configuration of the acetabulum included a horizontal acetabular roof owing to delayed iliac development and a notched acetabular roof with lateral bone deficiency. All children had thickened acetabular cartilage except for one child with osteogenesis imperfecta. Coxa vara was a common finding. All neonates displayed a very small beta angle (mean, 42 degrees) because the labrum lay more vertically, secondary to deep engagement of the femoral head in the acetabulum. Proximal femoral ossification was delayed in most children, which allows use of ultrasonography at a later age than is possible in the normal pediatric population. Hip ultrasonography in children with skeletal dysplasias can aid in early diagnosis and is useful in assessing hip morphology and development.

Pediatric hip sonography. Diagnosis and differential diagnosis.

As with any sonographic study, the accuracy of the examination is related to the skill and experience of the examiner. In this review of pediatric hip sonography, we have reviewed pitfalls and differential diagnoses for the infant suspected of DDH and for the older child presenting with a painful hip. The learning process for DDH evaluation is prolonged and more difficult than learning to assess the hip for effusion.

Effects of Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis.

BACKGROUND: To determine the extent and effects of increased metabolic demand represented by Pseudomonas colonization on body composition and resting energy expenditure in children with cystic fibrosis (CF). METHODS: The study comprised 18 stable children with CF, of whom 10 (6 male/4 female) were colonized with Pseudomonas species and 8 (4 male/4 female) were not. The groups were of similar age range and genotype. Measured resting energy expenditure (REE) was performed by open circuit indirect calorimetry and compared with predicted REE calculated from standard equations. Body composition was determined by dual-energy x-ray absorptiometry, including lean body mass (LBM), fat mass (FM), bone mineral density (BMD), and anterior-posterior spine density (APS); these were compared using z-scores. Routine pulmonary function testing assessed forced vital capacity, forced expiratory volume in 1 second (FEV1), and forced expiratory flow over middle half of vital capacity (FEF25% to 75%); these were compared as percent predicted. RESULTS: As expected, results of pulmonary function testing showed significant deterioration among the children colonized with Pseudomonas species when compared with the children who were not, while standard anthropometry showed no differences in weight, height, or weight-for-height percentile and respective z-scores. Although a trend of lower LBM was noted among the children colonized with Pseudomonas species, no significant differences were found between these children and children who were not colonized with Pseudomonas species when z-scores for LBM, FM, BMD, or APS were compared during body composition analysis. In addition, neither REE as kilocalories per day (kcal/d) nor REE expressed as a percent predicted by standard equations discriminated between subgroups of children colonized with Pseudomonas species and children who were not. However, metabolic demand, expressed as resting energy expenditure in kilocalories per kilogram (kcal/kg) of LBM (REE/LBM), revealed significant differences between children colonized with Pseudomonas species and children who were not (75.4+/-4.4 vs 58.6+/-2.9 kcal/kg, p < .05). CONCLUSIONS: The effect of Pseudomonas colonization on metabolic demand in children with CF can be accurately assessed by expressing resting energy expenditure as kilocalorie per kilogram of LBM, the active metabolic component of the body. The 50% increase in REE/LBM seen in the children colonized with Pseudomonas species represents the metabolic demand from the inflammatory burden and work of breathing resulting from the effects of the Pseudomonas colonization. The trend of a lower LBM in the children colonized with Pseudomonas species makes this finding even more dramatic.

Cost-effective imaging approach to the nonbilious vomiting infant.

OBJECTIVE: To develop a cost- and time-effective algorithm for differentiating hypertrophic pyloric stenosis (HPS) from other medical causes of emesis in infants referred from community-based pediatricians and family practitioners to the imaging department of a tertiary children's care facility. METHODS: Eighty-nine vomiting infants (22 females, 67 males) between the ages of 11 and 120 days (mean, 43.5 days) had received nothing by mouth for at least 1 hour before the study. Each child was assessed for duration of vomiting, status of body weight, time and volume of last ingestion, and time of last emesis. A #8 French (Sherwood Medical, St Louis, MO) nasogastric feeding tube was placed in the child's stomach. The contents were aspirated and measured to determine likelihood of HPS. An aspirated volume >/=5 mL implicated gastric outlet obstruction, and ultrasonography (US) was performed. If this study was positive for HPS, the patient was referred for surgery. If US was negative, an upper gastrointestinal series (UGI) was performed. An aspirated stomach contents volume <5 mL suggested a medical cause for the emesis, and UGI was performed. Pediatric surgeons with no knowledge of the volume results palpated the abdomens of 73 of 89 infants (82%). RESULTS: Twenty-three of 89 patients (25%) had HPS. The aspirate criteria for HPS had a sensitivity of 91%, a specificity of 88%, and an accuracy of 89%. Of the false-positive studies (total = 8), six were related to recent significant ingestion (within 2 hours of the study), and two were attributable to antral dysmotility. The surgeons palpated the mass in 10 of 19 patients (53%). Sensitivity and specificity were 53% and 93%, respectively. Only 6 of 89 infants (7%) required both US and UGI to determine the etiology of the nonbilious vomiting. By performing the UGI in 66 patients, it was also found that 14% had slow gastric emptying and 79% had gastroesophageal reflux. Eighty-one percent of the gastroesophageal reflux was significant. CONCLUSION: The volumetric method of determining the proper imaging study is cost- and time-effective in the evaluation of the nonbilious vomiting infant for pyloric stenosis. If US was performed initially in all patients referred for imaging, two studies would have been performed in 68 of 89 patients (76%) to define the etiology of the emesis. Because we used the volumetric method, 62 fewer imaging studies were performed, representing a savings of $4464 and 30 hours of physician time. If children are given nothing by mouth for 3 to 4 hours before gastric aspiration, the specificity of the volumetric method improves to 94%, and the accuracy improves to 96%.

Growth disturbance of the sternum and pectus deformities: imaging studies and clinical correlation.

BACKGROUND: Radiologic reports of "normal" chest are not uncommon when there clearly are irregularities of sternal ossification and maturation. Analysis of imaging studies of sternal deformities for growth disturbances is not common in the literature and is addressed in this manuscript. OBJECTIVE: To determine the influence of sternal growth on development of pectus deformities and correlate imaging studies with clinical aspects of different types of these deformities. MATERIAL AND METHODS: One hundred forty-one children and adolescents with pectus deformities were evaluated. Sternal growth was estimated through the development of radiographic indices that were available for 57 patients with pectus deformities and for 71 controls. Magnetic resonance imaging of the sternum was performed in two patients to correlate with radiographic information. RESULTS: Radiographic indices of the sternum suggested growth disturbances in three basic types of pectus carinatum deformities: superior, inferior and lateral, and in the localized type of pectus excavatum. CONCLUSION: Sternal growth seems to have an important influence on the development of carinatum superior; partial influence on carinatum inferior, carinatum lateral, and excavatum localized; and no influence on excavatum wide pectus deformities. The endochondral growth of the sternum and costal arches is an important concept that aids in the interpretation of imaging studies and the orthopedic approach to management of these deformities in children and adolescents.

Injury to the growth plate after Pemberton osteotomy.

The Pemberton osteotomy involves cutting directly into the iliopubic and ilioischial limbs of the triradiate cartilage of the acetabulum. Complete closure of the triradiate cartilage after this osteotomy has been described in case reports. The present experimental study was performed to determine whether physeal osseous bars formed after Pemberton osteotomy. Eight Pemberton osteotomies were performed in six piglets. The animals were killed, and the acetabula were studied with use of radiography, computed tomography, and histological analysis for evidence of physeal injury. Plain anteroposterior radiographs of the pelvis did not clearly demonstrate the formation of osseous bars. However, Bucholz radiographs, made with the acetabulum placed directly on the cassette, showed osseous bars in three of the four specimens that were studied in this manner. Histological sections of the eight specimens of triradiate cartilage demonstrated five osseous bars in the iliopubic limb and four in the ilioischial limb. In two specimens, there was disruption of the cartilage without osseous bridging. Only two of the eight specimens had normal histological findings in both the iliopubic and the ilioischial limb of the triradiate cartilage.

Ultrasonography and developmental dysplasia of the infant hip.

Hip sonography has been developed, refined, and critiqued for over 18 years. It is now widely accepted as a highly sensitive and useful technique for both the diagnosis and management of developmental dysplasia of the infant hip. Controversy continues surrounding the issue of when and how often hip sonography should be performed. Currently, clinical screening of newborns is the standard of care in the United States, with sonography employed selectively based on clinical findings. Universal ultrasound screening has been used in some countries and is under consideration by many investigators, using a variety of algorithms. This review will focus on recent reports dealing with issues of screening for developmental dysplasia of the infant hip and also will highlight techniques suggested for use in the treatment of development dysplasia of the infant hip.

Legg-Calvé-Perthes disease in girls. A comparison of the results with those seen in boys.

We reviewed the records and roentgenograms of all patients with Legg-Calvé-Perthes disease who had been seen at our institution between 1940 and 1996. One hundred and five girls (122 hips) and 470 boys (531 hips) were identified. Thus, 18 per cent of the 575 patients in the present series were girls. Seventeen (16 per cent) of the girls and sixty-one (13 per cent) of the boys had bilateral involvement. Although more girls than boys had severe involvement of the femoral head and the lateral pillar, we could not detect a significant difference between the two groups with respect to the distribution of the involvement of the hips according to the system of Catterall or the lateral pillar classification (p > 0.05, beta = 0.99). Serial roentgenograms that showed all four stages of the disease according to the system of Waldenström were available for fifty-two hips in girls and 184 hips in boys. A review of these roentgenograms revealed that the average ages of the girls at the stages of necrosis, fragmentation, reossification, and remodeling were 6.8, 7.3, 7.9, and 9.5 years, respectively, whereas the average ages of the boys were 6.8, 7.3, 7.9, and 9.9 years, respectively. Girls, however, had closure of the affected proximal femoral physis at an average age of 12.9 years, whereas boys had closure at an average age of 15.8 years. Therefore, girls had a shorter potential period for remodeling of the femoral head (average, 3.4 years) compared with boys (average, 5.9 years). Sixty-four girls (seventy-eight hips) and 363 boys (416 hips) had reached skeletal maturity by the time of the latest follow-up and were evaluated according to the system of Stulberg et al.; we could not detect a significant difference between boys and girls with respect to the distribution of the hips according to this system (p > 0.05, beta = 0.99). Although the numbers were too small for statistical analysis, our findings suggest that boys and girls who have the same Catterall or lateral pillar classification at the time of the initial evaluation can be expected to have similar outcomes according to the classification system of Stulberg et al.

Bone scintigraphy in the detection of chronic recurrent multifocal osteomyelitis.

UNLABELLED: In this study, we describe the importance of the whole-body bone scan in diagnosing the multifocality of chronic recurrent multifocal osteomyelitis (CRMO) and in distinguishing it from unifocal acute hematogenous osteomyelitis. MATERIALS: The medical records and two-phase, whole-body bone scans of 14 patients (mean age 10.5 yr) with the diagnosis of CRMO, were retrospectively reviewed. The diagnosis of CRMO was based on bone biopsy in 9 patients and clinical course/laboratory findings in 5. Bone scans were evaluated for geographic and anatomic locations of their lesions. Correlative radiographs of areas of abnormal uptake were performed to assess the radiographic appearance of the lesions. RESULTS: The presentation of the disease was localized to one painful, tender and swollen periarticular site 86% of the time. The number of lesions detected by bone scan varied from 1-18 (mean 6). Most lesions were metaphyseal, proximal or distal tibial lesions. Purely sclerotic or mixed (sclerosis and lysis) lesions were found on radiographs. Bilateral lesions were seen in 64% of patients. Biopsies were negative for organisms in all patients and exhibited subacute or chronic histologic changes in most instances. Complications of chronic hyperemia included marked overgrowth (5), diffuse demineralization (1), angular deformity (1) and length discrepancy (1). CONCLUSION: The identification of the multifocal configuration of the disease process by two-phase (soft-tissue and delayed) whole-body bone scintigraphy results in appropriate diagnosis and therapy of CRMO. Additional sites for possible bone biopsy become apparent for exclusion of other diagnoses. Supportive (nonsteroidal, anti-inflammatory medication) instead of antimicrobial therapy can be initiated with significant cost savings.

Computed tomography for femoral and tibial torsion in children with clubfoot.

Forty-seven children with 70 clubfeet had computed tomography studies performed to determine the degree of femoral, tibial, and total limb torsion in both lower limbs. The total limb torsion angle (angle between the axis of the femoral neck and the axis of the ankle), which describes the relationship between femoral and tibial torsion, was used to evaluate the whole rotational deformity of the lower limb. The children were between the ages of 2 and 10 years (mean, 5 years) at the time of the computed tomography study. The mean femoral torsion was 25 degrees in the limbs with a clubfoot and 23 degrees in the contralateral limbs of patients with a unilateral clubfoot. The mean tibial torsion was 25 degrees in the limbs with a clubfoot and 24 degrees in the contralateral limb of patients with a unilateral clubfoot. The authors observed decreases of anterior femoral torsion corresponding to increases in age, consistent with the observations made by other authors of studies of children without clubfoot. External tibial torsion increased with age, with similar values in limbs with and without clubfoot. Ten limbs (nine with clubfoot, one without clubfoot) had femoral torsion greater than the means plus one standard deviation and 12 limbs (eight with clubfoot, four without clubfoot) had tibial torsion less than the means minus one standard deviation. The authors found four limbs (all with clubfoot) in three patients with lower than the mean minus one standard deviation of the total limb torsion angle (intoeing). Overall, there was no appreciable difference in the amount of femoral or tibial torsion in limbs with and without a clubfoot.

Lateral femoral scan: an alternative method for assessing bone mineral density in children with cerebral palsy.

BACKGROUND: Children with cerebral palsy (CP), often nonambulatory and/or on anticonvulsants, are at increased risk for fractures. Bone mineral density (BMD) measured by the conventional techniques of dual-energy X-ray absorptiometry (DXA) often cannot be reliably or easily measured in these patients. OBJECTIVE: To find an alternative site to whole body, spine and hip that can be conveniently used to measure BMD in CP patients. MATERIALS AND METHODS: Having observed that CP patients prefer to lie on their sides, we explored measuring BMD at the distal femur in the lateral projection. A total of 92 scans were performed without sedation in 34 children and adolescents with CP, aged 4-19 years. Four femoral shaft subregions were created: two trabecular and two cortical. RESULTS: The coefficients of variation (CV %) were generally higher for opposite-side comparisons (n = 12 patients) than for same-side comparisons (n = 16 patients). For intra- and interobserver analyses, CV % were higher for cortical regions than for trabecular regions. Overall, the CV % were similar to those for hip and spine. CONCLUSION: This peripheral site in the femur should be considered as an alternative for patients with CP when whole-body, hip and spine DXA are not practical.