Nontraumatic Pediatric Head and Neck Emergencies: Resource for On-Call Radiologists.

The vast array of acute nontraumatic diseases encountered in the head and neck of pediatric patients can be intimidating for radiologists in training in a fast-paced emergency setting. Although there is some overlap of pediatric and adult diseases, congenital lesions and developmental variants are much more common in the pediatric population. Furthermore, the relative incidences of numerous infections and neoplasms differ between pediatric and adult populations. Young patients and/or those with developmental delays may have clinical histories that are difficult to elicit or nonspecific presentations, underscoring the importance of imaging in facilitating accurate and timely diagnoses. It is essential that radiologists caring for children be well versed in pediatric nontraumatic head and neck emergency imaging. The authors provide an on-call resource for radiology trainees, organized by anatomic location and highlighting key points, pearls, pitfalls, and mimics of many acute nontraumatic diseases in the pediatric head and neck. ©RSNA, 2024 Supplemental material is available for this article.

Spontaneous splenic rupture in a neonate: a case report and literature review.

Splenic rupture in a neonate is a rare but potentially fatal condition that may trigger evaluation for child abuse. It is a diagnosis of exclusion that has been reported in the surgical literature but may be underrecognized by pediatric radiologists. We report a case of a newborn with an unremarkable prenatal, delivery, and nursery course who presented with anemia, abdominal distension, and lethargy. Abdominal ultrasound with Doppler and computed tomography (CT) of the head, cervical spine, chest, abdomen, and pelvis without contrast showed findings of splenic rupture and anoxic brain injury. An extensive workup for traumatic, infectious, coagulopathic, and congenital etiologies was unrevealing, leading to a presumptive diagnosis of spontaneous splenic rupture in a neonate.

Diagnosis and Follow-up of Incidental Liver Lesions in Children.

ABSTRACT: Incidental liver lesions are identified in children without underlying liver disease or increased risk of hepatic malignancy in childhood. Clinical and imaging evaluation of incidental liver lesions can be complex and may require a multidisciplinary approach. This review aims to summarize the diagnostic process and follow-up of incidental liver lesions based on review of the literature, use of state-of-the-art imaging, and our institutional experience. Age at presentation, gender, alpha fetoprotein levels, tumor size, and imaging characteristics should all be taken into consideration to optimize diagnosis process. Some lesions, such as simple liver cyst, infantile hemangioma, focal nodular hyperplasia (FNH), and focal fatty lesions, have specific imaging characteristics. Recently, contrast-enhanced ultrasound (CEUS) was Food and Drug Administration (FDA)-approved for the evaluation of pediatric liver lesions. CEUS is most specific in lesions smaller than 3 cm and is most useful in the diagnosis of infantile hemangioma, FNH, and focal fatty lesions. The use of hepatobiliary contrast in MRI increases specificity in the diagnosis of FNH. Recently, lesion characteristics in MRI were found to correlate with subtypes of hepatocellular adenomas and associated risk for hemorrhage and malignant transformation. Biopsy should be considered when there are no specific imaging characteristics of a benign lesion. Surveillance with imaging and alpha fetoprotein (AFP) should be performed to confirm the stability of lesions when the diagnosis cannot be determined, and whenever biopsy is not feasible.

Evidence that ubiquinone is a required intermediate for rhodoquinone biosynthesis in Rhodospirillum rubrum.

Rhodoquinone (RQ) is an important cofactor used in the anaerobic energy metabolism of Rhodospirillum rubrum. RQ is structurally similar to ubiquinone (coenzyme Q or Q), a polyprenylated benzoquinone used in the aerobic respiratory chain. RQ is also found in several eukaryotic species that utilize a fumarate reductase pathway for anaerobic respiration, an important example being the parasitic helminths. RQ is not found in humans or other mammals, and therefore inhibition of its biosynthesis may provide a parasite-specific drug target. In this report, we describe several in vivo feeding experiments with R. rubrum used for the identification of RQ biosynthetic intermediates. Cultures of R. rubrum were grown in the presence of synthetic analogs of ubiquinone and the known Q biosynthetic precursors demethylubiquinone, demethoxyubiquinone, and demethyldemethoxyubiquinone, and assays were monitored for the formation of RQ(3). Data from time course experiments and S-adenosyl-l-methionine-dependent O-methyltransferase inhibition studies are discussed. Based on the results presented, we have demonstrated that Q is a required intermediate for the biosynthesis of RQ in R. rubrum.