Magnetic resonance imaging findings of synovial sarcoma in children: location-dependent differences.

BACKGROUND: While overall survival for children is greater than that for adults, synovial sarcoma remains an aggressive neoplasm with a potentially poor prognosis, and its magnetic resonance imaging (MRI) findings in children are not well described. OBJECTIVE: We aimed to characterize the spectrum of MRI findings of synovial sarcoma in children with respect to anatomical location and outcome. MATERIALS AND METHODS: Children with histologically confirmed synovial sarcoma and preoperative MRI performed within the past 11 years (2009-2020) were included. Two radiologists retrospectively reviewed each MRI to categorize location, signal characteristics and associated findings. Chi-square and Fisher exact tests were used to assess associations with locations and outcomes. RESULTS: This study included 23 children (13 girls, 10 boys; mean age: 12.7±4.2 years) with 7 axial, 8 proximal and 8 distal appendicular lesions. Kappa ranged from 0.53 to 1. MRI findings differed significantly between locations with axial lesions measuring larger (P=0.01) and more likely to contain fluid levels (P=0.02), triple sign (P=0.02), inhomogeneous signal (T1-weighted images, P=0.003; T2-weighted images, P=0.02, contrast-enhanced images, P=0.03) with all lesions containing partially solid composition (P=0.03). At a median follow-up of 14 months (interquartile range: 7-33 months), 39% relapsed. Predictors of relapse (P<0.05) included metastasis at presentation, larger lesions, axial lesions and MRI findings of fluid level, T1-weighted hyperintensity, inhomogeneous signal (T1- and T2-weighted images) and poorly circumscribed margins. CONCLUSION: A significant association was found between location and MRI findings in our cohort of children with synovial sarcoma. Axial lesions were more likely to be larger, appear heterogeneous and be associated with a worse outcome.

Initial Institutional Experience with 18F-Fluciclovine PET-CT in Biochemical Recurrence of Prostate Cancer.

OBJECTIVES: 18F-fluciclovine (fluciclovine) is an amino acid analog approved by the Food and Drug Administration for use as a radiotracer in positron emission tomography (PET) in men with biochemical recurrence of suspected prostate cancer. The purpose of this study was to investigate the initial institutional experience with 18F-fluciclovine in the evaluation of prostate cancer with biochemical recurrence. METHODS: This study was a retrospective review of 135 patients who underwent 18F-fluciclovine PET-computed tomography (PET-CT) at a single institution from August 2018 through January 2020. Prognostic information, including prostate-specific level antigen (PSA) at the time of diagnosis, initial risk, initial Gleason score, and initial stage, was reviewed as well as the PSA level at the time of the scan. The images were reviewed by two radiologists with fellowship training in nuclear medicine and additional training to interpret the fluciclovine studies. A minority of studies were reviewed by a third fellowship-trained radiologist under the guidance of the two nuclear medicine-trained radiologists. In cases with abnormal radiopharmaceutical uptake in lymph nodes, the short-axis dimension of the lymph node or largest lymph node with abnormal uptake was noted. If CT or bone scan was performed within 4 months of the 18F-fluciclovine PET-CT, findings on the alternate imaging were compared with the results of the 18F-fluciclovine PET-CT. RESULTS: Our institutional positivity rate was 75.6%, with 64 (67.4%) patients with metastatic disease and 71 (52.6%) patients with local recurrence detected by fluciclovine. As expected, the rate of positive examinations increased with increasing PSA values measured at the time of imaging (P < 0.001). Of the 54 patients with nodal disease, 35 had nonpathologically enlarged lymph nodes measuring <1 cm in maximum short-axis dimension. In more than half of the patients in this study, with conventional imaging, fluciclovine either discovered otherwise undetectable metastatic disease or suggested the presence of local recurrence. CONCLUSIONS: Our single-institution experience with 18F-fluciclovine PET-CT has the largest number of patients to date in the literature and demonstrates the ability of fluciclovine to help guide clinical management in the detection of early recurrent disease.

Third-trimester in utero fetal brain diffusion tensor imaging fiber tractography: a prospective longitudinal characterization of normal white matter tract development.

BACKGROUND: White matter is responsible for inter-neuronal connections throughout the brain that are a driving force in cognitive development. Diffusion tensor imaging (DTI) fiber tractography has been used to evaluate white matter development in the fetal brain; however, longitudinal studies of DTI fiber tractography to assess white matter development in the third trimester are lacking. OBJECTIVE: To characterize in utero longitudinal changes in the fetal brain DTI fiber tracts of normal third-trimester fetuses. MATERIALS AND METHODS: For this single-center prospective longitudinal observational pilot study, we recruited 28 pregnant females with normal third-trimester pregnancies who had routine prenatal ultrasound. MRI of the in utero fetal brain was performed with a Siemens 1.5-tesla (T) Espree scanner at 31 weeks, 33 weeks and 36 weeks of gestation, with 14 DTI tractography parameters quantified in 7 brain regions using DTI-studio version 2.4 (Johns Hopkins University, Baltimore, MD; n=98 measurements). We used multilevel mixed models to examine the relationship between longitudinal changes in DTI measurements and between 98 DTI measurements at 31 weeks and 4 routine fetal brain anatomical biometrics (n=392 assessments). RESULTS: We observed statistically significant decreases in radial diffusivity and apparent diffusion coefficient in 13 of 14 brain regions from 31 weeks to 36 weeks of gestation (P<0.001 for all regions except the genu of the corpus callosum). Significant decreases in radial diffusivity from weeks 33 to 36 and weeks 31 to 36 were seen in the corticospinal tracts, centrum semiovale, posterior limb of the internal capsule, and crus cerebri (P<0.001 for all). When considering all possible combinations of DTI fiber tract measurements and the routine morphological fetal brain biometrics, only 6% (24/392) had a significant association (P<0.05), indicating relative independence of the DTI fiber tract measurements from anatomical biometrics. CONCLUSION: In utero longitudinal changes in fetal brain DTI fiber tractography are quantifiable in normal third-trimester fetuses and are largely independent of morphological brain changes.

A primer for pediatric radiologists on infection control in an era of COVID-19.

Pediatric radiology departments across the globe face unique challenges in the midst of the current COVID-19 pandemic that have not been addressed in professional guidelines. Providing a safe environment for personnel while continuing to deliver optimal care to patients is feasible when abiding by fundamental recommendations. In this article, we review current infection control practices across the multiple pediatric institutions represented on the Society for Pediatric Radiology (SPR) Quality and Safety committee. We discuss the routes of infectious transmission and appropriate transmission-based precautions, in addition to exploring strategies to optimize personal protective equipment (PPE) supplies. This work serves as a summary of current evidence-based recommendations for infection control, and current best practices specific to pediatric radiologists.

Liposarcoma of the glottis: A report of an unusual diagnosis in an unusual location.

Liposarcoma of the larynx is a rare entity, typically well differentiated with a good prognosis. We present a patient who presented to ENT clinic with a 3-month history of hoarseness. Contrast-enhanced computed tomography of the neck demonstrated a 2.5-cm mass of the true vocal cord, which biopsy demonstrated to be dedifferentiated liposarcoma of the larynx. The patient went on to total laryngectomy with planned adjuvant radiation therapy. The presentation and imaging findings of laryngeal liposarcoma are nonspecific, but this neoplasm should be considered in the differential of masses in the head and neck.