Leonard P. Connolly

Early experience with fluorine-18 sodium fluoride bone PET in young patients with back pain.

Purpose: Skeletal positron emission tomography (PET) with fluorine-18 (18F) sodium fluoride (18F NaF) is an alternative to technetium-99m (99mTc)methylene diphosphonate (MDP) scintigraphy. Experience with pediatric PET is sparse, primarily in oncology. This study assesses the role of 18F NaF in evaluating young patients with back pain. Methods: Ninety-four 18F NaF PET scans were performed in 94 patients (27 males, 67 females; mean age, 15 years; range, 4-26 years) with back pain. Three-dimensional PET acquisition was performed 30 minutes after administration of 18F NaF (2.1 MBq/kg; maximum, 148 MBq). Radiation doses are presented for 18F NaF and 99mTc MDP. Results: 18F NaF PET revealed a possible cause of back pain in 55% (52/94). Fifteen patients had 2 or more potential sources of back pain. Diagnoses by PET were pars interarticularis/pedicle stress (34%), spinous process injury (16%), vertebral body ring apophyseal injury (14%), stress at a transitional vertebra-sacral articulation (7%), and sacroiliac joint inflammation/stress (3%). Comparing 18F NaF PET with 99mTc MDP scintigraphy, time between injection and scanning was shorter (0.5 hours vs 3 hours), radiation dosimetry was similar (3.5 mGy vs 2.8 mGy effective dose for a 55-kg patient for 18F NaF and 99mTc MDP, respectively), and cost of radiopharmaceutical was higher. Conclusions: 18F NaF bone PET can detect a variety of skeletal abnormalities in young patients with back pain. Relative to 99mTc MDP, images are of higher resolution. Total time from tracer administration to completion is shorter, and radiation dosimetry is similar. Higher cost for 18F NaF may be offset by enhanced patient throughput.

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.

Pediatric Brown Adipose Tissue: Detection, Epidemiology, and Differences from Adults

OBJECTIVES To evaluate the prevalence and factors affecting the detection of active brown adipose tissue (BAT) in children and adolescents using (18)F-fluorodeoxyglucose positron emission tomography. STUDY DESIGN A total of 385 positron emission tomography scans performed for various oncologic indications in 172 patients aged 5-21 years were reviewed. BAT activity was detected by visual inspection as present or absent in the neck, thorax, and abdomen based on its well-characterized and typical appearance and then quantified by comparing the (18)F-fluorodeoxyglucose activity in the cervical-supraclavicular depots with that measured in the liver. Clinical indices were recorded. RESULTS The BAT detection rate was not significantly different between boys and girls (43.3% vs 45.3%). BAT activity was found most often in the cervical-supraclavicular depots. The highest percentage of patients with detectable BAT and the highest BAT/liver activity were in the 13- to 14.99-year age group in both males and females (P = .005). Body mass index percentile correlated inversely with BAT activity (P = .012). BAT activity did not correlate with outdoor temperature or clinical diagnosis. CONCLUSION Under typical clinical imaging conditions, BAT is detected more frequently in children than in adults. BAT activity increases from childhood into adolescence, when it is detected in almost half of patients, and it correlates inversely with obesity, suggesting that BAT may play a prominent role in pediatric metabolism.

99mTechnetium dimercapto-succinic acid renal scintigraphy abnormalities in infants with sterile high grade vesicoureteral reflux

PURPOSE Although vesicoureteral reflux associated with bacteriuria may cause renal scarring, sterile reflux is thought not to cause renal injury. We determined the incidence and associated characteristics of renal abnormalities using 99mtechnetium(Tc) dimercapto-succinic acid (DMSA) renal scintigraphy in infants with high grade vesicoureteral reflux but no history of urinary tract infection. MATERIALS AND METHODS We retrospectively reviewed the results of 99mTc-DMSA renal scintigraphy and renal ultrasonography performed during the first 6 months of life in infants with vesicoureteral reflux detected during the postnatal evaluation of prenatal hydronephrosis or sibling reflux screening. Those with a history of urinary tract infection, or evidence of ureteropelvic junction or bladder outlet obstruction were excluded from study. RESULTS Of the 28 male and 6 female infants who met study criteria vesicoureteral reflux was bilateral in 25 and unilateral in 9. Reflux grade was IV or V, II or III and I in 38, 18 and 3 of the 59 refluxing renal units, respectively. 99mTc-DMSA renal scintigraphy revealed parenchymal abnormalities in 24 refluxing renal units (41%) in 22 patients (65%), of whom 19 (86%) were male and 15 (68%) had bilateral reflux. We noted differential uptake less than 40% with and without cortical defects in 10 and 7 refluxing units, respectively, and cortical defects only in 7. Of the 24 refluxing units with abnormalities 21 were associated with grade IV or V and 3 with grade II or III reflux. Ultrasound showed evidence of renal injury in only 7 of the 17 patients (41%) in whom 99mTc-DMSA scintigraphy was abnormal. CONCLUSIONS In our study the majority of infants with high grade reflux had decreased differential function and/or cortical defects. Parenchymal defects detected by 99mTc-DMSA renal scintigraphy were often not identified by renal ultrasound. Therefore, 99mTc-DMSA renal scintigraphy is especially useful for initially evaluating infants with high grade, sterile vesicoureteral reflux.

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.

Lingual Thyroid in Children: A Rare Clinical Entity†

Objectives/Hypothesis: To study the presentation, management, and long‐term outcome of children presenting with lingual thyroid.

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.

Natural History of Vesicoureteral Reflux in Siblings

PURPOSE We attempted to assess the natural course of vesicoureteral reflux after it was detected in asymptomatic siblings of children with reflux, and to determine predictors of and time to resolution. MATERIALS AND METHODS We reviewed the records and radionuclide cystograms of 76 girls and 32 boys 2 weeks to 103 months old (mean age 21 months) with vesicoureteral reflux detected in a sibling screening program. Predictors were determined using logistic regression and survival analysis. RESULTS Vesicoureteral reflux resolved in 52.8% of cases at a mean followup of 18.5 months. Yearly resolution rates exceeded 28%. Predictors of the likelihood of resolution were not identified. At diagnosis unilateral reflux and mild reflux were independent and univariate predictors, respectively, of more rapid resolution. CONCLUSIONS By showing that spontaneous resolution is likely for children with vesicoureteral reflux detected in a sibling screening program, this study supports nonsurgical management with annual imaging evaluation.

Applications of nuclear medicine in pediatric oncology.

&NA; Nuclear medicine is important in the diagnosis, staging, and long‐term surveillance of a number of pediatric cancers. Skeletal scintigraphy is used to evaluate primary skeletal cancers, such as osteosarcoma and Ewing sarcoma, and nonskeletal cancers such as neuroblastoma, lymphoma, medulloblastoma, rhabdomyosarcoma, and retinoblastoma. Metaiodobenzylguanidine scintigraphy is valuable in examinations of children with neuroblastoma. The therapeutic response of primary bone and brain tumors can be assessed using TI‐201 and Tc‐99m MIBI scintigraphy. Imaging strategies for staging and monitoring the therapeutic response of Hodgkins lymphoma include Ga‐67 citrate scintigraphy. Pediatric oncologic applications of positron emission tomography are being investigated extensively.

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.