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.

Total body bone mineral density in young children: influence of head bone mineral density.

Dual-energy X-ray absorptiometry (DXA) with its short scan time, low radiation dose, and high precision and accuracy have made this technique particularly suitable for measuring total body bone mineral density (TBMD) in children. Other published reports have related TBMD to age in children 2-18 years of age. However, in young normal children aged 2-9 years (51 girls, 43 boys), we found that regression equations for TBMD with age as the predictor did not explain enough of the variance to warrant their use for predicting TBMD (adjusted R2 0.47, females; 0.41, males). Subtotal BMD (TBMD-head BMD) is predicted better by age because of a possibly invalid adult algorithm for head BMD (adjusted R2 0.73, females; 0.71, males).

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%.

Scintigraphic manifestations of infraction of the second metatarsal (Freiberg's disease).

Two patients with Freiberg's infraction of the second metatarsal are presented. The scintigraphic pattern of a photopenic defect with hyperactive collar is demonstrated as evidence of the existence of avascular necrosis or infarction in this entity. The photopenia was appreciated only on pinhole collimator images in our first patient. The later revascularization phase of avascular necrosis with diffuse increase in uptake is demonstrated scintigraphically in the second patient.

Postprandial blush in multiphase bone scanning.

The presence of transient soft-tissue activity in the left side and the lower midportion of the abdomen on the early phases of the multiphase bone scan represents postprandial physiologic hyperemia of the small intestine. The bowel uptake was present in all 33 patients ingesting food between 15 min and 3.5 hr before scanning. In those patients who had not eaten within 4 hr of the study, only 25% demonstrated bowel activity. The observation of bowel uptake is important in differentiating a physiologic phenomenon from pathologic accumulations of activity. Pathology should be ruled out when bowel activity is not located in the usual left flank and lower mid-abdomen, or is present in a fasting individual.

Uterine blush in multiphase bone imaging.

Uterine visualization was found as a transient finding in the early phases of the biphasic and triphasic bone scans in 29 of 29 postmenarchial adolescent and young adult females studied regardless of phase of the menstrual cycle. This observation differs from reports of uterine uptake in Meckel's scanning where visualization occurred only in the menstrual or secretory phases of the cycle. None of 12 control patients (six males and six premenarchial females) showed intrapelvic activity on the blood-pool images. The accumulation of radiotracer in the uterus should be expected as a normal transient physiologic phenomenon in young women after menarche.

Sternal infarction in sickle-cell anemia: concise communication.

Bone scintigraphy in six children with sickle-cell anemia has demonstrated infarction of bony segments of the sternum. Anterior oblique views of the thorax provided best visualization of the infarcts which were seen as areas of decreased bone tracer accumulation.

SPECT imaging of para-axial neurofibromatosis with technetium-99m DTPA.

Single photon emission computed tomography (SPECT) was used to study uptake of technetium-99m diethylenetriaminepentaacetic acid ([99mTc]DTPA) by para-axial neurofibromas in 13 patients. SPECT imaging led to better resolution of uptake in nine instances and detection of 12 lesions unsuspected on planar imaging (PI). Two false-positive instances and one false-negative instance of uptake are described. The planning of the surgical approach and placement of graft material for spinal fusion was assisted by SPECT in two patients. One patient with disability secondary to recurring abdominal pain had detection of the causative lesion by SPECT and subsequent relief of her symptoms following excision of the tumor. SPECT imaging of soft-tissue tumors of neurofibromatosis appears to have potential use in preplanning surgery on structural or cosmetic lesions, in the detection of occult lesions, and the monitoring of patients with neurofibromatosis at regular intervals.

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.

Detection of talocalcaneal coalitions by magnification bone scintigraphy.

Fibrocartilaginous talocalcaneal coalitions are very difficult to identify on plain radiography in symptomatic children and adolescents before gross ossification occurs. Computed tomography (CT) has been successful in identifying osseous and some fibro-osseous coalitions. In this series, magnification imaging of the tarsus on bone scintigraphy in the medial-lateral projection correctly identified talocalcaneal coalitions, seven of the nine bars were fibrous or fibro-osseous. Three of the fibrous lesions were equivocal or normal on conventional radiography and CT. Physiologic accumulations of activity in the growing hind foot are also presented from a control pediatric population. Magnification scintigraphy of the hind foot is offered as an adjunct to plain radiography and CT in the diagnosis of elusive nonosseous subtalar bars.

Scintigraphic evaluation of the growth plate.

Multiphase bone scintigraphy is used to assess growth plate function in the growing skeleton. It can identify an evolving total or segmental closure by comparing an affected plate with a contralateral normal plate. Although visual interpretation is usually adequate, quantitative methods permit a more objective assessment. Total or partial closure occurs in response to trauma and infection; plate closure also may be induced surgically to prevent progressive leg length inequality. As new orthopaedic procedures for correcting early plate closure are developed, the need for accurate physiological assessment of the growth plate is critical.

A multiscintigraphic approach to imaging of lymphedema and other causes of the congenitally enlarged extremity.

Nuclear imaging in the definition of the components of the congenitally enlarged extremity is important in the design of a successful therapeutic regimen. In our series of 32 patients evaluated for primary lymphedema, 85% were determined to have abnormalities that were not purely lymphatic in origin. The multiscintigraphic approach defines the components of the lymphatic and vascular systems with the use of technetium-99m [99mTc] antimony sulfide colloid (99mTc Sb2S3) for lymphatic, 99mTc diethylenetriamine pentacetic acid (DTPA) for capillary-interstitial, and 99mTc-tagged red blood cells for venous systems.

Imaging techniques in childhood arthritis.

Technological advances in imaging have given physicians caring for children with arthritis a greater opportunity to detect abnormalities early in the course of a disease and better methods for monitoring chronic changes. Indications for using radiography, bone densitometry, nuclear medicine, ultrasound, CT scanning, and MR imaging are discussed in this article. In this era of managed care, the practicing clinician is urged more than ever to consult with the radiologist in selecting the study or sequence of studies to be used in particular case. In this way, evaluation can be limited to the most effective strategy from both the clinical and cost perspectives.

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.

Protrusio acetabuli in neurofibromatosis: nondysplastic and dysplastic forms.

Protrusio acetabuli (PA) in neurofibromatosis is not well documented in the literature. Two forms of PA, a nondysplastic and dysplastic type, are noted. Twenty-one percent of hips (13 patients) in neurofibromatosis were found to have some form of acetabular protrusion abnormality. In the control group (83 patients) without stigmata of neurofibromatosis, only 9% of hips were associated with PA. The progressive dysplastic form of PA is usually associated with contiguous soft-tissue neurofibromas and lumbar dural ectasia. The nondysplastic, nonprogressive form has less of an association with regional soft-tissue abnormalities and almost no association with dural dysplasia.

Evaluation of physeal behavior in response to epiphyseodesis with the use of serial magnetic resonance imaging.

The stages in the closure of the growth plate after percutaneous epiphyseodesis were studied in fourteen patients (eight girls and six boys) with coronal T1-weighted spin-echo images and coronal field-echo images of the knee. A total of thirty-three magnetic-resonance imaging studies of the knee were made the first week, the fourth month, the eighth month, or one year after the epiphyseodesis. A mature bridge of bone was seen at the operative sites approximately eight months after the operation. In the central undisturbed area between the operative sites, there was a progressive decrease in the width of the physeal cartilage that remained visible eight months after the operation. Growth recovery lines were not seen postoperatively in any patient, and the physis closed in all of the patients. The physis of the adjacent untreated bone served as a control bone and showed neither a change in width nor any growth recovery lines. Magnetic resonance-imaging studies provide excellent visualization of the anatomical changes that lead to closure of the physis after an epiphyseodesis, and we believe that these studies provide a method of assessment of the physis after an injury.

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.

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.

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.

Real-time ultrasound in the diagnosis of congenital dislocation and dysplasia of the hip.

A technique of examining the infant hip joint with real-time ultrasound is described. Since the cartilaginous femoral head is clearly imaged by ultrasound, anatomical structures and their relationships can be accurately determined. Dislocated hips are easily detected and subluxations also can be visualized. We report our experience with 131 examinations in 104 patients, comprising 259 single hip studies. Of 83 patients who were previously untreated, there were 178 hip studies with three false-negative and four false-positive ultrasound results. No dislocations were missed. Twenty-seven patients who were already being treated were examined to assess hip location, comprising a total of 81 hip studies. In some cases the patients were examined while in an abduction device, cast, or Pavlik harness. In one case a dislocation was not detected. The method of examination using real-time ultrasound is considered to be reliable, accurate, and a useful adjunct to radiography. The advantages are that it is non-invasive, portable, and involves no exposure to radiation.