Imaging approach to pediatric calvarial bulges.

Palpable calvarial lesions in children may require multi-modality imaging for adequate characterization due to non-specific clinical features. Causative lesions range from benign incidental lesions to highly aggressive pathologies. While tissue sampling may be required for some lesions, others have a typical imaging appearance, and an informed imaging approach facilitates diagnosis. This review illustrates imaging findings of common and clinically important focal pediatric calvarial bulges to aid the radiologist in narrowing the differential diagnosis and directing appropriate referral. We focus on birth-related lesions, congenital abnormalities, and modeling disturbances (i.e., those that produce a change in calvarial contour early in development), normal variants, and neoplastic lesions with their mimics.

Pediatric orbital lesions: neoplastic extraocular soft-tissue lesions.

Pediatric neoplastic extraocular soft-tissue lesions in the orbit are uncommon. Early multimodality imaging work-up and recognition of the key imaging features of these lesions allow narrowing of the differential diagnoses in order to direct timely management. In this paper, the authors present a multimodality approach to the imaging work-up of these lesions and highlight the use of ocular ultrasound as a first imaging modality where appropriate. We will discuss vascular neoplasms (congenital hemangioma, infantile hemangioma), optic nerve lesions (meningioma, optic nerve glioma), and other neoplastic lesions (plexiform neurofibroma, teratoma, chloroma, rhabdomyosarcoma, infantile fibrosarcoma, schwannoma).

Pediatric orbital lesions: ocular pathologies.

Orbital pathologies can be broadly classified as ocular, extra-ocular soft-tissue (non-neoplastic and neoplastic), osseous, and traumatic. In part 1 of this orbital series, the authors will discuss the differential diagnosis and key imaging features of pediatric ocular pathologies. These include congenital and developmental lesions (microphthalmos, anophthalmos, persistent fetal vasculature, coloboma, morning glory disc anomaly, retinopathy of prematurity, Coats disease), optic disc drusen, infective and inflammatory lesions (uveitis, toxocariasis, toxoplasmosis), and ocular neoplasms (retinoblastoma, retinal hamartoma, choroidal melanoma, choroidal nevus). This pictorial review provides a practical approach to the imaging work-up of these anomalies with a focus on ocular US as the first imaging modality and additional use of CT and/or MRI for the evaluation of intracranial abnormalities. The characteristic imaging features of the non-neoplastic mimics of retinoblastoma, such as persistent fetal vasculature and Coats disease, are also highlighted.

Pediatric orbital lesions: bony and traumatic lesions.

Orbital pathologies can be broadly classified as ocular lesions, extraocular soft-tissue pathologies (non-neoplastic and neoplastic), and bony and traumatic lesions. In this paper, we discuss the key imaging features and differential diagnoses of bony and traumatic lesions of the pediatric orbit and globe, emphasizing the role of CT and MRI as the primary imaging modalities. In addition, we highlight the adjunctive role of ocular sonography in the diagnosis of intraocular foreign bodies and discuss the primary role of sonography in the diagnosis of traumatic retinal detachment.

Pediatric orbital lesions: non-neoplastic extraocular soft-tissue lesions.

Orbital pathologies can be broadly classified as ocular, extraocular soft-tissue (non-neoplastic and neoplastic), osseous, and traumatic. In this paper, we discuss the key imaging features and differential diagnoses of congenital and developmental lesions (dermoid cyst, dermolipoma), infective and inflammatory pathologies (pre-septal cellulitis, orbital cellulitis, optic neuritis, chalazion, thyroid ophthalmopathy, orbital pseudotumor), and non-neoplastic vascular anomalies (venous malformation, lymphatic malformation, carotid-cavernous fistula), emphasizing the key role of CT and MRI in the imaging work-up. In addition, we highlight the adjunctive role of ocular ultrasound in the diagnosis of dermoid cyst and chalazion, and discuss the primary role of ultrasound in the diagnosis of vascular malformations.

Properties of ultrasound-rapid MRI clinical diagnostic pathway in suspected pediatric appendicitis.

OBJECTIVE: to determine diagnostic accuracy of an US-MRI clinical diagnostic pathway to detect appendicitis in the emergency department (ED). STUDY DESIGN: prospective cohort study of 624 previously healthy children 4-17 years old undergoing US for suspected appendicitis and clinical re-assessment. Children with non-diagnostic USs and persistent appendicitis concern/conclusive US-reassessment discrepancies underwent ultra-rapid MRI (US-MRI pathway), interpreted as positive, negative or non-diagnostic. Cases with missed appendicitis, negative appendectomies, and CT utilization were considered clinically diagnostically inaccurate. Primary outcome was the proportion of accurate diagnoses of appendicitis/lack thereof by the pathway. RESULTS: 150/624 (24%) children had appendicitis;255 USs (40.9%) were non-diagnostic. Of 139 US-MRI pathway children (after 117 non-diagnostic and 22 conclusive USs), 137 [98.6%; 95% CI 0.96-1.00] had clinically accurate outcomes (1 CT, 1 negative appendectomy): sensitivity 18/18 [100%], specificity 119/121 [98.3%], positive predictive value 18/20 [90.5%], negative predictive value 119/119 [100%]. MRI imaging accuracy was 134/139 (96.4%); 3 MRIs were non-diagnostic (no appendicitis). In the overall algorithm, 616/624 [98.7% (0.97-0.99)] patients had accurate outcomes: 147/150 (98.0%) appendicitis cases had confirmatory surgeries (3 CTs) and 469/474 (98.9%) appendicitis-negative children had no surgery/CT. CONCLUSION: this study demonstrated high clinical accuracy of the US-rapid-MRI pathway in suspected pediatric appendicitis after non-diagnostic US.

Non-Hodgkin Lymphoma Imaging Spectrum in Children, Adolescents, and Young Adults.

In children, adolescents, and young adults (CAYA), non-Hodgkin lymphoma (NHL) is characterized by various age-related dissimilarities in tumor aggressiveness, prevailing pathologic subtypes, and imaging features, as well as potentially different treatment outcomes. Understanding the imaging spectrum of NHL in CAYA with particular attention to children and adolescents is critical for radiologists to support the clinical decision making by the treating physicians and other health care practitioners. The authors discuss the currently performed imaging modalities including radiography, US, CT, MRI, and PET in the diagnosis, staging, and assessment of the treatment response. Familiarity with diagnostic imaging challenges during image acquisition, processing, and interpretation is required when managing patients with NHL. The authors describe potentially problematic and life-threatening scenarios that require prompt management. Moreover, the authors address the unprecedented urge to understand the imaging patterns of possible treatment-related complications of the therapeutic agents used in NHL clinical trials and in practice. Online supplemental material is available for this article. ©RSNA, 2022.

Posttransplant Lymphoproliferative Disorder in Children: A 360-degree Perspective.

An earlier incorrect version of this article appeared online. This article was corrected on December 17, 2019.

Correction to: FDG uptake in cervical lymph nodes in children without head and neck cancer.

The original version of this article unfortunately contained a mistake. Author name Alaa Bakkari was incorrect. The correct spelling is given above.

The clinical impact of 18F-FDG PET/CT in extracranial pediatric germ cell tumors.

BACKGROUND: Extracranial germ cell tumors are an uncommon pediatric malignancy with limited information on the clinical impact of 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) in the literature. OBJECTIVE: The purpose of this study was to evaluate and compare the clinical impact on management of 18F-FDG PET/CT with diagnostic computed tomography (CT) in pediatric extracranial germ cell tumor. MATERIALS AND METHODS: The list of 18F-FDG PET/CT performed for extracranial germ cell tumor between May 2007 and November 2015 was obtained from the nuclear medicine database. 18F-FDG PET/CT and concurrent diagnostic CT were obtained and independently reviewed. Additionally, the patients' charts were reviewed for duration of follow-up and biopsy when available. The impact of 18F-FDG PET/CT compared with diagnostic CT on staging and patient management was demonstrated by chart review, imaging findings and follow-up studies. RESULTS: During the study period, 9 children (5 males and 4 females; age range: 1.6-17 years, mode age: 14 years) had 11 18F-FDG PET/CT studies for the evaluation of germ cell tumor. Diagnostic CTs were available for comparison in 8 patients (10 18F-FDG PET/CT studies). The average interval between diagnostic CT and PET/CT was 7.2 days (range: 0-37 days). In total, five lesions concerning for active malignancy were identified on diagnostic CT while seven were identified on PET/CT. Overall, 18F-FDG PET/CT resulted in a change in management in 3 of the 9 patients (33%). CONCLUSION: 18F-FDG PET/CT had a significant impact on the management of pediatric germ cell tumors in this retrospective study. Continued multicenter studies are required secondary to the rarity of this tumor to demonstrate the benefit of 18F-FDG PET/CT in particular clinical scenarios.

FDG uptake in cervical lymph nodes in children without head and neck cancer.

BACKGROUND: Reactive cervical lymphadenopathy is common in children and may demonstrate increased 18F-fluoro-deoxyglucose (18F-FDG) uptake on positron emission tomography/computed tomography (PET/CT). OBJECTIVE: We sought to evaluate the frequency and significance of 18F-FDG uptake by neck lymph nodes in children with no history of head and neck cancer. MATERIALS AND METHODS: The charts of 244 patients (114 female, mean age: 10.4 years) with a variety of tumors such as lymphoma and post-transplant lymphoproliferative diseases (PTLD), but no head and neck cancers, who had undergone 18F-FDG PET/CT were reviewed retrospectively. Using the maximum standardized uptake value (SUVmax), increased 18F-FDG uptake by neck lymph nodes was recorded and compared with the final diagnosis based on follow-up studies or biopsy results. RESULTS: Neck lymph node uptake was identified in 70/244 (28.6%) of the patients. In 38 patients, the lymph nodes were benign. In eight patients, the lymph nodes were malignant (seven PTLD and one lymphoma). In 24 patients, we were not able to confirm the final diagnosis. Seven out of the eight malignant lymph nodes were positive for PTLD. The mean SUVmax was significantly higher in malignant lesions (4.2) compared with benign lesions (2.1) (P = 0.00049). CONCLUSION: 18F-FDG uptake in neck lymph nodes is common in children and is frequently due to reactive lymph nodes, especially when the SUVmax is <3.2. The frequency of malignant cervical lymph nodes is higher in PTLD patients compared with other groups.