Susan A. Connolly

Vesicoureteral Reflux in Children: Incidence and Severity in Siblings

PURPOSE We attempted to determine the incidence of vesicoureteral reflux in asymptomatic siblings of children with reflux at different ages and assess the incidence of renal damage in asymptomatic siblings with reflux. MATERIALS AND METHODS We reviewed radionuclide cystograms of 482 consecutively referred siblings of children with vesicoureteral reflux, including 295 girls and 187 boys 2 weeks to 12.8 years old (mean age 2.8 years). Ultrasonograms and renal cortical scintigrams of children with reflux were evaluated. All siblings were considered asymptomatic by the referring physicians. RESULTS The overall incidence of vesicoureteral reflux was 36.5%, and the incidence in girls and boys was 39.3 and 32.1%, respectively. Children 24 months old or younger had the highest incidence (45.7%) and the highest risk of bilateral reflux. From ages 25 to 72 months the incidence of reflux was 33.1% and in siblings older than 72 months it was 7%. Reflux of urine to the level of the renal pelvis was detected in 28.6% of all referred siblings. Renal damage was observed on sonography or scintigraphy in 4.7% of the siblings with reflux. CONCLUSIONS The high incidence of vesicoureteral reflux through age 72 months indicates that it is important to screen siblings of children with reflux at an early age to prevent renal damage, which can occur in the absence of symptomatic urinary tract infection.

Fetal brain volumetry through MRI volumetric reconstruction and segmentation.

PurposeFetal MRI volumetry is a useful technique but it is limited by a dependency upon motion-free scans, tedious manual segmentation, and spatial inaccuracy due to thick-slice scans. An image processing pipeline that addresses these limitations was developed and tested.Materials and methodsThe principal sequences acquired in fetal MRI clinical practice are multiple orthogonal single-shot fast spin echo scans. State-of-the-art image processing techniques were used for inter-slice motion correction and super-resolution reconstruction of high-resolution volumetric images from these scans. The reconstructed volume images were processed with intensity non-uniformity correction and the fetal brain extracted by using supervised automated segmentation.ResultsReconstruction, segmentation and volumetry of the fetal brains for a cohort of twenty-five clinically acquired fetal MRI scans was done. Performance metrics for volume reconstruction, segmentation and volumetry were determined by comparing to manual tracings in five randomly chosen cases. Finally, analysis of the fetal brain and parenchymal volumes was performed based on the gestational age of the fetuses.ConclusionThe image processing pipeline developed in this study enables volume rendering and accurate fetal brain volumetry by addressing the limitations of current volumetry techniques, which include dependency on motion-free scans, manual segmentation, and inaccurate thick-slice interpolation.

Rib stress fractures.

The ribs are an uncommon site of stress fracture. Typical locations are the first rib anterolaterally, the fourth through ninth ribs laterally and posterolaterally, and the posteromedial upper ribs. Muscular forces are predominantly responsible for these fractures. This article reviews the mechanisms of injury in various activities and illustrates the scintigraphic appearance of rib stress fractures.

MRI for Detection of Abscess in Acute Osteomyelitis of the Pelvis in Children

OBJECTIVE We analyzed our experience with MRI of pelvic acute hematogenous osteomyelitis (AHO) to address the following questions: What does MRI reveal about bone involvement? How often are fluid collections indicative of abscess shown? Are clinical parameters predictive of the cases in which MRI would be more beneficial? MATERIALS AND METHODS We retrospectively reviewed the imaging studies and medical records from the past 5 years of 38 children ranging in age from 25 to 211 months who were diagnosed with pelvic osteomyelitis using MRI. Statistical analysis of demographic and clinical variables was compared between patients with an abscess (n = 21) and those without (n = 17) who were identified on MRI. RESULTS Osteomyelitis involved metaphyseal equivalent sites in every case (n = 38), with single bone involvement in 24 (63%) and contiguous bone involvement in the remaining 14 (37%). Fluid collections indicative of an abscess were seen in 21 cases (55%), and abscess drainage was performed in 10 (26%). Univariate analysis of demographic and clinical variables between patients with and without an abscess indicated no significant differences for any variable except erythrocyte sedimentation rate (ESR) (74 +/- 19 vs 56 +/- 24 mm/h; p< 0.05, Students t test). CONCLUSION Childhood pelvic AHO is relatively uncommon and produces variable signs and symptoms that are often attributed to another process. The results of our study show the ability of MRI to provide additional information that affected patient management in cases of pelvic abscess. We therefore advocate the use of MRI as the imaging technique of choice for any child suspected of having pelvic AHO.

Osteofibrous dysplasia and adamantinoma in children and adolescents: a clinicopathologic reappraisal.

Osteofibrous dysplasia (OFD) and adamantinoma are rare and most commonly arise in the tibia of young individuals. Although OFD has typical histopathologic features, areas resembling OFD have often been noted at the periphery of otherwise classic adamantinomas, and some have suggested that OFD may be either a precursor to or a regressive phase of adamantinoma. The so-called OFD-like adamantinoma encompasses some features of both OFD and adamantinoma. We studied the clinical, imaging, histopathologic, immunohistochemical, ultrastructural, and molecular features of 16 OFD and 8 adamantinomas (5 OFD-like and 3 classic) in an attempt to further define their morphology, clinical course, and relationship. Patients with OFD were generally younger than those with adamantinoma. Osteoblastic and osteoclastic activity was more prominent in OFD than in OFD-like adamantinoma. In addition to the inconspicuous small clusters of epithelial cells in OFD-like adamantinoma, isolated keratin-positive cells with a unique ultrastructural hybrid fibroblastic-epithelial phenotype were found in the stroma of all OFD and OFD-like adamantinomas. Fluorescence in situ hybridization analysis revealed trisomies 7, 8, and/or 12 in the spindle cell stroma of OFD, OFD-like, and classic adamantinoma, supporting a neoplastic origin of OFD and a common histogenesis for all 3 lesions. Trisomies were not observed in osteoblasts or osteoclasts suggesting that the osseous component is reactive and non-neoplastic. Of the 11 OFD patients with follow-up (median, 4.5 y), all 3 who underwent incisional biopsy had persistent, nonprogressive disease and 2 of 8 who underwent curettage or wide excision had recurrence; none developed adamantinoma. All 6 adamantinoma patients with follow-up (3 classic and 3 OFD-like) were treated with wide excision. One with classic adamantinoma died of pulmonary metastases 9 years after presentation; the other 5 were free of disease with a median follow-up of 12 years. None of the classic adamantinomas evolved into OFD-like adamantinoma or OFD. Although the histopathology, immunohistochemistry, ultrastructure, and cytogenetics indicate that these lesions are closely related, our data and the literature suggest that only classic adamantinoma has malignant potential. OFD, OFD-like adamantinoma, and classic adamantinoma appear to show a progressive complexity of cytogenetic aberrations, perhaps indicative of a multistep neoplastic transformation.

IMAGING OF SPORTS INJURIES IN CHILDREN AND ADOLESCENTS

Imaging plays an important role in the diagnosis and management of sports injuries of childhood and adolescence. The injuries discussed are typical of those seen in the skeletally immature athlete. Imaging specialists must be able to apply the full range of imaging modalities when evaluating the injured young athlete.

Post-closed reduction perfusion magnetic resonance imaging as a predictor of avascular necrosis in developmental hip dysplasia: a preliminary report.

Introduction: Avascular necrosis (AVN) of the femoral head remains a major complication in the treatment of developmental dysplasia of the hip (DDH) in infants. We performed a retrospective analysis to look at the predictive ability of postclosed reduction contrast-enhanced magnetic resonance imaging (MRI) for AVN after closed reduction in DDH. Methods: Twenty-eight hips in 27 infants (aged 1-11 months) with idiopathic hip dislocations who had failed brace treatment underwent closed reduction ± adductor tenotomy and spica cast application under general anesthesia. Magnetic resonance imaging of the hips after intravenous gadolinium contrast injection for evaluation of epiphyseal perfusion was obtained immediately after cast application. Patients were followed with serial radiographs for a minimum of 1 year after closed reduction. Presence of AVN was determined by the presence of any one of the 5 Salter criteria by 2 readers. Magnetic resonance imaging was graded as normal, asymmetric enhancement, focal decreased enhancement, or global decreased enhancement by 2 radiologists. Results: Six (21%) of 28 hips showed evidence of clinically significant AVN on follow-up radiographs. Fifty percent of the hips with AVN, but only 2 of 22 hips without AVN, showed a global decreased MRI enhancement (P < 0.05, Fisher exact test). Multivariate logistic regression indicated that a global decreased enhancement was associated with a significantly higher risk of developing AVN (P < 0.01), independently of age at reduction (P = 0.02) and abduction angle. Conclusions: In addition to accurate anatomical assessment of a closed reduction in DDH, gadolinium-enhanced MRI provides information about femoral head perfusion that may be predictive for future AVN. At present, it is premature to use the perfusion information for routine clinical use. However, it opens the door to studies looking at repositioning or alternative reduction methods that may reduce the risk of AVN in this higher risk group.

The use of magnetic resonance imaging to predict ACL graft structural properties

Magnetic resonance imaging (MRI) could potentially be used to non-invasively predict the strength of an ACL graft after ACL reconstruction. We hypothesized that the volume and T2 relaxation parameters of the ACL graft measured with MRI will predict the graft structural properties and anteroposterior (AP) laxity of the reconstructed knee. Nine goats underwent ACL reconstruction using a patellar tendon autograft augmented with a collagen or collagen-platelet composite. After 6 weeks of healing, the animals were euthanized, and the reconstructed knees were retrieved and imaged on a 3T scanner. AP laxity was measured prior to dissecting out the femur-graft-tibia constructs which were then tested to tensile failure to determine the structural properties. Regression analysis indicated a statistically significant relationship between the graft volume and the failure load (r(2)=0.502; p=0.049). When graft volume was normalized to the T2 relaxation time, the relationship was even greater (r(2)=0.687; p=0.011). There was a significant correlation between the graft volume and the linear stiffness (r(2)=0.847; p<0.001), which remained significant with T2 normalization (r(2)=0.764; p=0.002). For AP laxity at 30° flexion, there was not a significant correlation with graft volume, but there was a significant correlation with volume normalized by the T2 relaxation time (r(2)=0.512; p=0.046). These results suggest that MRI volumetric measures combined with graft T2 properties may be useful in predicting the structural properties of ACL grafts.

Rachitic Changes, Demineralization, and Fracture Risk in Healthy Infants and Toddlers with Vitamin D Deficiency

PURPOSE To examine radiographic findings in children with vitamin D deficiency in comparison with biochemical marker levels and prevalence of fractures. MATERIALS AND METHODS The parents or guardians of all participants provided written informed consent at the time of enrollment. The institutional review board approved the protocol, and HIPAA guidelines were followed. From a prospective sample of children seen for routine clinical care, 40 children with vitamin D deficiency (25-hydroxyvitamin D [25-OHD] level, ≤ 20 ng/mL) were identified, and high-detail computed radiographs of the wrists and knees were obtained. The children ranged in age from 8 to 24 months. Radiographs were scored by three readers with use of the 10-point Thacher score for rachitic changes and a five-point scale for demineralization. Serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone levels were determined. Fracture history was obtained for 35 of the 40 patients (88%). RESULTS All readers identified rachitic changes at both readings in two patients (5%) and demineralization in two patients (5%). Interrater agreement was 65% for rachitic changes (κ = 0.33) and 70% for demineralization (κ = 0.37). When the majority of the raters determined that rachitic changes were absent at both readings, alkaline phosphatase levels were lower than those with other assessments (median, 267 vs 515 U/L [4.4589 vs 8.6005 μkat/L]; P = .01). When most raters determined that demineralization was present at both readings, serum 25-OHD levels were lower than those at other assessments (median, 9.0 vs 17.5 ng/mL [22.464 vs 43.68 nmol/L]; P = .02). No fractures were reported or identified radiographically. CONCLUSION In infants and toddlers with vitamin D deficiency, rachitic changes and definite demineralization are uncommon and fracture risk is low.

Young athletes with low back pain: skeletal scintigraphy of conditions other than pars interarticularis stress.

Purpose: Skeletal scintigraphy is an important method for showing evidence of stress injuries affecting the partes interarticulares of young athletes with low back pain. Other etiologies of low back pain may also cause uptake abnormalities in these patients. How often do the results of skeletal scintigraphy support diagnoses other than stress injuries to the partes interarticulares and what are these diagnoses? Materials and Methods: We retrospectively reviewed the records of 209 young patients (149 females, 60 males; age range: 8–21 years, mean: 15.7 years) with low back pain and no previously treated vertebral condition who were consecutively referred from a sports medicine clinic to skeletal scintigraphy. Results: Sites of high uptake supportive of diagnoses other than pars interarticularis stress were shown in 36 (17%) of the 209 patients. Other diagnoses supported by skeletal scintigraphy included stress at the articulation between a transitional vertebra and the sacrum, injuries to the vertebral body ring apophysis, sacral fracture, spinous process injury, and sacroiliac joint stress. Conclusion: Skeletal scintigraphy shows uptake abnormalities supportive of diagnoses other than pars interarticularis stress in a significant number of young patients with low back pain. The uptake abnormalities shown are usually stress-related in this select population.