Jeannette M. Perez-Rossello

Prevalence of Vitamin D Deficiency Among Healthy Infants and Toddlers

OBJECTIVES To determine the prevalence of vitamin D deficiency and to examine whether 25-hydroxyvitamin D (25OHD) concentration varies as a function of skin pigmentation, season, sun exposure, breastfeeding, and vitamin D supplementation. DESIGN Cross-sectional sample. SETTING Urban primary care clinic. PARTICIPANTS Healthy infants and toddlers (N = 380) who were seen for a routine health visit. OUTCOME MEASURES Primary outcomes were serum 25OHD and parathyroid hormone levels; secondary measures included data on sun exposure, nutrition, skin pigmentation, and parental health habits. Wrist and knee radiographs were obtained for vitamin D-deficient participants. RESULTS The prevalence of vitamin D deficiency (< or =20 ng/mL) was 12.1% (44 of 365 participants), and 146 participants (40.0%) had levels below an accepted optimal threshold (< or =30 ng/mL). The prevalence did not vary between infants and toddlers or by skin pigmentation. There was an inverse correlation between serum 25OHD and parathyroid hormone levels (infants: r = -0.27, P < .001; toddlers: r = -0.20, P = .02). In multivariable models, breastfeeding without supplementation among infants and lower milk intake among toddlers were significant predictors of vitamin D deficiency. In vitamin D-deficient participants, 3 participants (7.5%) exhibited rachitic changes on radiographs, whereas 13 (32.5%) had evidence of demineralization. CONCLUSIONS Suboptimal vitamin D status is common among otherwise healthy young children. Predictors of vitamin D status vary in infants vs toddlers, information that is important to consider in the care of these young patients. One-third of vitamin D-deficient participants exhibited demineralization, highlighting the deleterious skeletal effects of this condition.

Evaluating children with fractures for child physical abuse

Fractures are common injuries caused by child abuse. Although the consequences of failing to diagnose an abusive injury in a child can be grave, incorrectly diagnosing child abuse in a child whose fractures have another etiology can be distressing for a family. The aim of this report is to review recent advances in the understanding of fracture specificity, the mechanism of fractures, and other medical diseases that predispose to fractures in infants and children. This clinical report will aid physicians in developing an evidence-based differential diagnosis and performing the appropriate evaluation when assessing a child with fractures.

Skeletal Trauma in Child Abuse: Detection with 18F-NaF PET

PURPOSE To evaluate the sensitivity of fluorine 18-labeled sodium fluoride ((18)F-NaF) positron emission tomography (PET) for assessment of skeletal trauma in pediatric patients suspected of having been abused and to compare the diagnostic performance of this examination with that of high-detail skeletal survey. MATERIALS AND METHODS The institutional review board approved this retrospective study and determined that it was in accordance with regulations of HIPAA privacy rule 45, Code of Federal Regulations parts 160 and 164, and that the criteria for waived patient authorization were met. The baseline skeletal survey and PET images obtained in 22 patients younger than 2 years between September 2007 and January 2009 were reviewed. Fourteen patients also underwent follow-up skeletal survey. The PET images were interpreted by two pediatric nuclear medicine physicians. The initially obtained skeletal survey images were interpreted blindly by a pediatric radiologist. A second pediatric radiologist interpreted the follow-up skeletal survey images in conjunction with the baseline survey images and rendered a final interpretation for the 14 patients in whom both baseline and follow-up skeletal survey data were available, which served as the reference standard. RESULTS A total of 156 fractures were detected at baseline skeletal survey, and 200 fractures were detected at PET. Compared with the reference standard (findings in the 14 patients who underwent baseline and follow-up skeletal survey), PET had sensitivities of 85% for the detection of all fractures, 92% for the detection of thoracic fractures (ribs, sternum, clavicle, and scapula), 93% for the detection of posterior rib fractures, and 67% for the detection of classic metaphyseal lesions (CMLs), defined as a series of microfractures across the metaphysis. Compared with the reference standard, baseline skeletal survey had sensitivities of 72% for the detection of all fractures, 68% for the detection of thoracic fractures, 73% for the detection of posterior rib fractures, and 80% for the detection of CMLs. CONCLUSION (18)F-NaF PET had greater sensitivity in the overall detection of fractures related to child abuse than did baseline skeletal survey. (18)F-NaF PET was superior in the detection of rib fractures in particular. Thus, (18)F-NaF PET is an attractive choice for evaluation of suspected child abuse, an application in which high sensitivity is desirable. Because of the lower sensitivity of PET in the detection of CMLs, a characteristic fracture in child abuse, initial radiographic evaluation remains necessary.

Ultrasound Versus Computerized Tomography for Evaluating Urolithiasis

PURPOSE We prospectively evaluated the precision of ultrasound and computerized tomography to diagnose urinary stones in children and determined whether these differences in radiological findings have any impact on clinical management. MATERIALS AND METHODS A total of 50 consecutive patients with suspected urolithiasis underwent computerized tomography and ultrasound. Two radiologists reviewed each study independently in blinded fashion. When a difference in findings was detected, 8 pediatric urologists reviewed the case. Clinical management was based on the results of each radiological test independently. Statistical analysis was performed using Fishers exact test. RESULTS Compared to computerized tomography ultrasound had 76% sensitivity and 100% specificity. In 8 patients stone(s) seen on computerized tomography was not seen on ultrasound. The average size of missed stones was 2.3 mm. In 7 patients computerized tomography showed stones bilaterally but stone was seen on only 1 side on ultrasound. When evaluating the clinical impact, the ultrasound/computerized tomography discrepancy did not result in any significant change in clinical management except in 4 cases. In these cases ultrasound findings suggested that additional imaging was required and, thus, stone(s) in the distal ureter would have been identified on subsequent imaging. CONCLUSIONS Although computerized tomography is more sensitive for detecting urolithiasis than ultrasound, the difference in usefulness between the 2 radiological tests may not be clinically significant. Given concerns for the potentially harmful cumulative long-term effect of radiation, ultrasound should be considered the first imaging test in children with suspected urolithiasis.

Prevalence of the classic metaphyseal lesion in infants at low versus high risk for abuse.

OBJECTIVE The purpose of this article is to determine the relative likelihood of encountering a classic metaphyseal lesion in infants at low and high risk for abuse. MATERIALS AND METHODS This 10-year retrospective study compared the prevalence of the classic metaphyseal lesion on high-detail American College of Radiology-standardized skeletal surveys in infants at low and high risk for abuse. Low-risk infants met all of the following criteria: skull fracture without significant intracranial injury on CT, history of a fall, and no other social risk factors for abuse. High-risk infants met all of the following criteria: significant intracranial injury, retinal hemorrhages, and skeletal injuries (excluding classic metaphyseal lesions and skull fractures). Differences between the two groups were calculated using the Fisher exact test. RESULTS There were 42 low-risk infants (age range, 0.4-12 months; mean age, 4.4 months) and 18 high-risk infants (age range, 0.8-10.3 months; mean age, 4.6 months). At least one classic metaphyseal lesion was identified in nine infants (50%) in the high-risk category. No classic metaphyseal lesions were identified in the low-risk group. The relative prevalence of classic metaphyseal lesions in the low-risk group (0/42) versus that in the high-risk group (9/18) was statistically significant (p < 0.0001; 95% CI, 0-8% to 29-76%). CONCLUSION Classic metaphyseal lesions are commonly encountered in infants at high risk for abuse and are rare in infants with skull fractures associated with falls, but no other risk factors. The findings support the view that the classic metaphyseal lesion is a high-specificity indicator of infant abuse.

In vivo assessment of optimal b‐value range for perfusion‐insensitive apparent diffusion coefficient imaging

PURPOSE To assess the optimal b-values range for perfusion-insensitive apparent diffusion coefficient (ADC) imaging of abdominal organs using short-duration DW-MRI acquisitions with currently available ADC estimation methods. METHODS DW-MRI data of 15 subjects were acquired with eight b-values in the range of 5-800 s∕mm(2). The reference-standard, a perfusion insensitive, ADC value (ADC(IVIM)), was computed using an intravoxel incoherent motion (IVIM) model with all acquired diffusion-weighted images. Simulated DW-MRI data was generated using an IVIM model with b-values in the range of 0-1200 s∕mm(2). Monoexponential ADC estimates were calculated using: (1) Two-point estimator (ADC(2)); (2) least squares three-point (ADC(3)) estimator and; (3) Rician noise model estimator (ADC(R)). The authors found the optimal b-values for perfusion-insensitive ADC calculations by minimizing the relative root mean square error (RRMS) between the ADC(IVIM) and the monoexponential ADC values for each estimation method and organ. RESULTS Low b-value = 300 s∕mm(2) and high b-value = 1200 s∕mm(2) minimized the RRMS between the estimated ADC and the reference-standard ADC(IVIM) to less than 5% using the ADC(3) estimator. By considering only the in vivo DW-MRI data, the combination of low b-value = 270 s∕mm(2) and high b-value of 800 s∕mm(2) minimized the RRMS between the estimated ADC and the reference-standard ADC(IVIM) to <7% using the ADC(3) estimator. For all estimators, the RRMS between the estimated ADC and the reference standard ADC correlated strongly with the perfusion-fraction parameter of the IVIM model (r = [0.78-0.83], p ≤ 0.003). CONCLUSIONS The perfusion compartment in DW-MRI signal decay correlates strongly with the RRMS in ADC estimates from short-duration DW-MRI. The impact of the perfusion compartment on ADC estimations depends, however, on the choice of b-values and estimation method utilized. Likewise, perfusion-related errors can be reduced to <7% by carefully selecting the b-values used for ADC calculations and method of estimation.

Characterization of fast and slow diffusion from diffusion-weighted MRI of pediatric Crohn's disease.

To characterize fast and slow diffusion components in diffusion‐weighted magnetic resonance imaging (DW‐MRI) of pediatric Crohns disease (CD). Overall diffusivity reduction as measured by the apparent diffusion coefficient (ADC) in patients with CD has been previously demonstrated. However, the ADC reduction may be due to changes in either fast or slow diffusion components. In this study we distinguished between the fast and slow diffusion components in the DW‐MRI signal decay of pediatric CD.

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.

Absence of Rickets in Infants with Fatal Abusive Head Trauma and Classic Metaphyseal Lesions

PURPOSE To determine if rickets is present in cases of infant homicide with classic metaphyseal lesions (CMLs) and other skeletal injuries. MATERIALS AND METHODS This study was exempt from the institutional human subjects board review because all infants were deceased. An archival review (1984-2012) was performed of the radiologic and histopathologic findings of 46 consecutive infant fatalities referred from the state medical examiners office for the evaluation of possible child abuse. Thirty infants with distal femoral histologic material were identified. Additional inclusion criteria were as follows: (a) The medical examiner determined that the infant had sustained a head injury and that the manner of death was a homicide, (b) at least one CML was evident at skeletal survey, (c) CMLs were confirmed at autopsy, and (d) non-CML fractures were also present. Nine infants (mean age, 3.9 months; age range, 1-9 months) were identified. Two pediatric radiologists independently reviewed the skeletal surveys for rachitic changes at the wrists and knees. A bone and soft tissue pathologist reviewed the distal femoral histologic slices for rickets. RESULTS There were no radiographic or pathologic features of rickets in the cohort. CONCLUSION The findings provide no support for the view that the CML is due to rickets. Rather, they strengthen a robust literature that states that the CML is a traumatic injury commonly encountered in physically abused infants.

Metaphyseal Fragmentation with Physiologic Bowing: A Finding Not to Be Confused with the Classic Metaphyseal Lesion

OBJECTIVE The purpose of this study was to describe the varied appearances of metaphyseal fragmentation associated with physiologic bowing and to estimate their frequency in children undergoing radiographic evaluation. CONCLUSION The results of this study suggest that metaphyseal fragmentation is occasionally encountered in children with physiologic bowing. Results of a systematic imaging assessment should minimize confusion of this innocent radiologic alteration with the classic metaphyseal lesion of child abuse.