Brown adipose tissue 18F-FDG uptake in pediatric PET/CT imaging.

Positron emission tomography (PET) using [F-18]2-fluoro-2-deoxyglucose (FDG) fused with CT ((18)F-FDG PET/CT) has been widely adopted in oncological imaging. However, it is known that benign lesions and other metabolically active tissues, such as brown adipose tissue (BAT), can accumulate (18)F-FDG, potentially resulting in false-positive interpretation. Previous studies have reported that (18)F-FDG uptake in BAT is more common in children than in adults. We illustrate BAT FDG uptake in various anatomical locations in children and adolescents. We also review what is known about the effects of patient-related physical attributes and environmental temperatures on BAT FDG uptake, and discuss methods used to reduce BAT FDG uptake on (18)F-FDG PET.

Value of postmortem thoracic CT over radiography in imaging of pediatric rib fractures.

BACKGROUND: Studies have reported that thoracic CT may provide greater sensitivity compared with radiography in detection of pediatric rib fractures and fracture healing. The additional sensitivity afforded by thoracic CT may have medicolegal implications where abuse is suspected. OBJECTIVE: To determine the additional value of postmortem thoracic CT compared with radiography in detecting pediatric rib fractures, and fracture healing, using autopsy findings as a gold standard. MATERIALS AND METHODS: We retrospectively reviewed 56 coroner's cases with postmortem radiography and CT thoracic survey. All studies underwent primary interpretation by one or two radiologists. The study radiologist independently reviewed all images from 13 patients with positive findings on radiography, CT or autopsy. Sensitivity and specificity between observers and imaging modalities were compared. RESULTS: Primary interpretation: Fractures were recognized on radiography in 5/12 patients who had fractures found at autopsy, and on CT in 8/12 patients. In total, 29% (24/83) of fractures were reported on radiography, and 51% (52/101) of fractures were reported on CT. Study radiologist: Fractures were recognized on radiography in 7/12 patients who had fractures found at autopsy, and on CT in 11/12 patients. In total, 46% (38/83) of fractures were reported on radiography, and 85% (86/101) of fractures were reported on CT. CONCLUSION: Postmortem thoracic CT provides greater sensitivity than radiography in detecting pediatric rib fractures, most notably in anterior and posterior fractures. However, the degree of improvement in sensitivity provided by CT might depend on observer experience.

Whole-body MR angiography: initial experience in imaging pediatric vasculopathy.

Radiological assessment of vasculopathy in children is typically undertaken with ultrasonography, echocardiography, conventional angiography, computed tomography and, more recently, positron emission tomography. Drawbacks of these modalities include radiation exposure or, in the case of ultrasonography, the dependence on operator skills and sufficient acoustic windows. With advancements in MR technology, which have improved sensitivity and shortened scan times, whole-body magnetic resonance angiography (WB-MRA) lends itself as a potential "one-stop shop" for vascular imaging. Currently, WB-MRA is primarily used in adult patients with atherosclerosis or multifocal regional vasculopathy. WB-MRA has not been employed in the routine assessment of pediatric vascular disease. The purpose of this article is to describe and illustrate our WB-MRA imaging technique for evaluation of pediatric vasculopathy.

Osteonecrosis in an adolescent with non-Hodgkin lymphoma resembling a new metastatic lesion on (18)F-FDG PET/CT.

Osteonecrosis may result from complications in a variety of pediatric diseases and, in the early stages of healing, may be characterized by inflammation and hyperemia. While traditionally assessed by bone scintigraphy, osteonecrosis may also present upon [F-18]2-fluoro-2-deoxyglucose PET/CT. Differentiation of osteonecrosis from metastatic lesions is important to ensure accurate disease staging and to avoid unnecessary imaging and biopsy. Osteonecrosis typically presents at the interface of weight-bearing joints after prolonged chemotherapy with corticosteroid administration, although prevalence is greater in adults than in children. We describe a case of unilateral osteonecrosis in the tibia of an adolescent lymphoma patient, which first presented on FDG-PET/CT imaging after 2 months of combination chemotherapy with corticosteroid administration. This report should aid in recognizing rapid-onset osteonecrosis with atypical sites of involvement in pediatric patients.