Dabrafenib and trametinib in Langerhans cell histiocytosis and other histiocytic disorders.

The standard treatment for Langerhans cell histiocytosis (LCH) is chemotherapy, although the failure rates are high. Since MAP-kinase activating mutations are found in most cases, BRAF- and MEK-inhibitors have been used successfully to treat patients with refractory or relapsed disease. However, data on long-term responses in children are limited and there are no data on the use of these inhibitors as first-line therapy. We treated 34 patients (26 with LCH, 2 with juvenile xanthogranuloma, 2 with Rosai-Dorfman disease, and 4 with presumed single site-central nervous system histiocytosis) with dabrafenib and/or trametinib, either as first line or after relapse or failure of chemotherapy. Sixteen patients, aged 1.3-21 years, had disease that was recurrent or refractory to chemotherapy, nine of whom had multisystem LCH with risk-organ involvement. With a median treatment duration of 4.3 years, 15 (94%) patients have sustained favorable responses. Eighteen patients, aged 0.2-45 years, received an inhibitor as first-line treatment. All of these have had sustained favorable responses, with a median treatment duration of 2.5 years. Three patients with presumed isolated central nervous system/pituitary stalk histiocytosis had stabilization or improvement of their disease. Overall, inhibitors were well tolerated. Five patients with single-system LCH discontinued therapy and remain off therapy without recurrence. In contrast, all four patients with multisystem disease who discontinued therapy had to restart treatment. Our data suggest that children suffering from histiocytoses can be treated safely and effectively with dabrafenib or trametinib. Additional studies are, however, needed to determine the long-term safety and optimal duration of therapy.

Neonatal vascular anomalies manifesting as soft-tissue masses.

The broad and heterogeneous spectrum of vascular anomalies ranges from an innocuous localized cutaneous discoloration to complex, extensive and life-threatening diagnoses. While many of these lesions are present at birth, smaller and deeper lesions might be clinically occult for months or years. Certain vascular anomalies commonly manifest in the prenatal or neonatal period and often have suggestive clinical and imaging features that can aid the radiologist in making a correct diagnosis. The characteristics of such lesions presenting very early in life, particularly those manifesting as soft-tissue masses, are the focus of this review.

Congenital hemangioma of the face-Value of fetal MRI with prenatal ultrasound.

We report the presentation, workup, and pre/perinatal management of a fetus with a large congenital hemangioma of the face. Hemangiomas are benign vascular neoplasms frequently encountered in neonates and infants. The less common congenital variant develops in utero and can present on prenatal ultrasound with diagnostic uncertainty as well as clinical implications for delivery. The differential diagnosis for these solid vascular masses when located in the head and neck includes myofibroma, kaposiform hemangioendothelioma, teratoma, and encephalocele. Potential clinical issues relate to size and location of the mass and include airway obstruction, disruption in development or compression of the globe, invasion into the cranial vault, bleeding and ulceration, and high output heart failure. Prenatal ultrasound and MRI play an important role in the diagnosis of congenital hemangiomas and planning for delivery and immediate postnatal cares.

Spaced radiology: encouraging durable memory using spaced testing in pediatric radiology.

Applied memory research in the field of cognitive and educational psychology has generated a large body of data to support the use of spacing and testing to promote long-term or durable memory. Despite the consensus of this scientific community, most learners, including radiology residents, do not utilize these tools for learning new information. We present a discussion of these parallel and synergistic learning techniques and their incorporation into a software platform, called Spaced Radiology, which we created for teaching radiology residents. Specifically, this software uses these evidence-based strategies to teach pediatric radiology through a flashcard deck system.

Non-contrast three-dimensional gradient recalled echo Dixon-based magnetic resonance angiography/venography in children.

Magnetic resonance imaging (MRI) has been considered a valuable diagnostic tool for noninvasive imaging of the vasculature in children and adults for more than two decades. While a variety of non-contrast MRI methods have been described for imaging of both arteries and veins (e.g., time-of-flight, phase contrast, and balanced steady-state free precession imaging), contrast-enhanced magnetic resonance angiography/venography are the most commonly employed vascular imaging techniques due to their high spatial and contrast resolutions and general reliability. In this technical innovation article, we describe a novel 3-D respiratory-triggered gradient recalled echo Dixon-based MR angiography/MR venography technique that provides high-resolution anatomical imaging of the vasculature of the neck, body and extremities without the need for intravenous contrast material or breath-holding.

Decreased rectal meconium signal on MRI in fetuses with open spinal dysraphism.

OBJECTIVE: To evaluate rectal meconium signal in fetuses with open spinal dysraphism and correlate findings with postnatal exam. METHODS: This is a single-institution Institutional Review Board-approved Health Insurance Portability and Accountability Act (HIPAA) compliant retrospective analysis of fetal MRIs of open spinal dysraphism from 2004 to 2016. Fetuses with diagnostic T1-weighted images and postnatal follow-up at our institution were included. RESULTS: A total of 115 fetuses (average gestational age 23.9 ± 3.6 weeks) met inclusion criteria. Of these, 80% (92/115) had T1 hyperintense rectal meconium signal. Average height of the meconium column, measured from the base of the bladder to its most inferior extent, was 9.2 ± 4.3 mm in fetuses ≥20-week gestational age and 11.1 ± 4.4 mm in fetuses ≥23-week gestational age (n = 110) . None had bowel dilation. One of 115 fetuses had a simple form of anorectal malformation allowing complete repair in the neonatal period, but this fetus had a normal meconium column height on fetal MRI of 22 mm. The remaining 23/115 fetuses with lack of normal rectal meconium signal were born without evidence of anorectal malformation. CONCLUSION: Decreased or absent T1-hyperintense rectal meconium signal in fetuses with open spinal dysraphism does not correlate with imperforate anus postnatal and may be a reflection of neurogenic bowel in this patient population.

Fowler syndrome and fetal MRI findings: a genetic disorder mimicking hydranencephaly/hydrocephalus.

Fetal ventriculomegaly is a common referral for prenatal MRI, with possible etiologies being hydrocephalus and hydranencephaly. The underlying cause of hydranencephaly is unknown, but many have suggested that the characteristic supratentorial injury is related to idiopathic bilateral occlusions of the internal carotid arteries from an acquired or destructive event. Fowler syndrome is a rare genetic disorder that causes fetal akinesia and a proliferative vasculopathy that can result in an apparent hydranencephaly-hydrocephaly complex. On prenatal imaging, the presence of significant parenchymal loss in the supratentorial and infratentorial brain is a clue to the diagnosis, which should prompt early genetic testing.

Imaging of Pediatric Growth Plate Disturbances.

The growth plates, or physes, are visible on virtually all images obtained in skeletally immature children. The proper function of these growth plates depends on an intricate balance between chondrocyte proliferation, which requires nourishment from the epiphyseal vessels, and chondrocyte death, which requires the integrity of the metaphyseal vessels. Therefore, injury to the growth plate (ie, direct insult) or vascular compromise on either side of the growth plate (ie, indirect insult) can cause growth plate dysfunction. Direct growth plate insults occur most commonly with Salter-Harris fractures, and injuries that allow the transphyseal communication of vessels are at a higher risk for subsequent transphyseal bone bridge formation. Indirect insults lead to different sequelae that are based on whether the epiphyseal blood supply or metaphyseal blood supply is compromised. Epiphyseal osteonecrosis can result in slowed longitudinal bone growth, with possible growth plate closure, and is often accompanied by an abnormal secondary ossification center. In contrast, the disruption of metaphyseal blood supply alters endochondral ossification and allows the persistence of chondrocytes within the metaphysis, which appear as focal or diffuse growth plate widening. Imaging remains critical for detecting acute injuries and identifying subsequent growth disturbances. Depending on the imaging findings and patient factors, these growth disturbances may be amenable to conservative or surgical treatment. Therefore, an understanding of the anatomy and physiologic features of the normal growth plate and the associated pathophysiologic conditions can increase diagnostic accuracy, enable radiologists to anticipate future growth disturbances, and ensure optimal imaging, with the ultimate goal of timely and appropriate intervention. ©RSNA, 2017.