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Background: Pseudoprogression (PsP) is a recognized phenomenon after radiotherapy (RT) for high-grade glioma but is poorly characterized for low-grade glioma (LGG). We sought to characterize PsP for pediatric LGG patients treated with RT, with particular focus on the role of RT modality using photon-based intensity-modulated RT (IMRT) or proton beam therapy (PBT)., Methods: Serial MRI scans from 83 pediatric LGG patients managed at 2 institutions between 1998 and 2017 were evaluated. PsP was scored when a progressive lesion subsequently decreased or stabilized for at least a year without therapy., Results: Thirty-two patients (39%) were treated with IMRT, and 51 (61%) were treated with PBT. Median RT dose for the cohort was 50.4 Gy(RBE) (range, 45-59.4 Gy[RBE]). PsP was identified in 31 patients (37%), including 8/32 IMRT patients (25%) and 23/51 PBT patients (45%). PBT patients were significantly more likely to have post-RT enlargement (hazard ratio [HR] 2.15, 95% CI: 1.06-4.38, P = 0.048). RT dose >50.4 Gy(RBE) similarly predicted higher rates of PsP (HR 2.61, 95% CI: 1.20-5.68, P = 0.016). Multivariable analysis confirmed the independent effects of RT modality (P = 0.03) and RT dose (P = 0.01) on PsP incidence. Local progression occurred in 10 patients: 7 IMRT patients (22%) and 3 PBT patients (6%), with a trend toward improved local control for PBT patients (HR 0.34, 95% CI: 0.10-1.18, P = 0.099)., Conclusions: These data highlight substantial rates of PsP among pediatric LGG patients, particularly those treated with PBT. PsP should be considered when assessing response to RT in LGG patients within the first year after RT., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Background and Purpose: Embryonal tumor with multilayered rosettes (ETMR), C19MC-altered, is a recently described, rare central nervous system tumor. To our knowledge, the imaging findings of this tumor have not been systematically evaluated in the neuroradiology literature. We present here the clinical, radiological, and pathological correlation of a case series of this very rare tumor, including the full range of anatomic compartment presentations (supratentorial, infratentorial, and spinal)., Methods: We retrospectively analyzed 7 (4M, 3F) pathologically-proven cases of ETMR referred to our institution between 2007 and 2017. We demonstrate the imaging characteristics of this tumor on CT and MRI with advanced imaging., Results: All of the patients are children (ages 1-12). On MR imaging of ETMR, contrast enhancement is often heterogeneous and minimal if any, and there is no significant surrounding T2 fluid-attenuated inversion recovery (FLAIR) hyperintensity to suggest edema. The lesions were often expansile with no evidence of infiltration of the fiber tracks that were displaced by the tumor mass. Diffusion-weighted imaging often demonstrated restricted diffusion within ETMRs. On magnetic resonance spectroscopy (MRS), the choline/creatine (Cho/Cr) ratio is increased, with low N-acetylaspartate (NAA) or NAA/Cho ratio, typical of high-grade tumors., Conclusion: We demonstrate the conventional and advanced imaging characteristics of ETMR, including MRS and diffusion tensor imaging, which, to our knowledge, have not been systematically evaluated in the radiology literature. The knowledge gained may potentially impact patient management, especially in inoperable cases and in locations where it is risky to perform a biopsy., (© 2018 by the American Society of Neuroimaging.)

Purpose: Nuclear medicine studies have previously been utilized to assess for blockage of cerebrospinal fluid (CSF) flow prior to intraventricular chemotherapy infusions. To assess CSF flow without nuclear medicine studies, we obtained cine phase-contrast MRI sequences that assess CSF flow from the fourth ventricle down to the sacrum., Methods: In three clinical trials, 18 patients with recurrent malignant posterior fossa tumors underwent implantation of a ventricular access device (VAD) into the fourth ventricle, either with or without simultaneous tumor resection. Prior to infusing therapeutic agents into the VAD, cine MRI phase-contrast CSF flow sequences of the brain and total spine were performed. Velocity encoding (VENC) of 5 and 10 cm/s was used to confirm CSF flow from the fourth ventricular outlets to the cervical, thoracic, and lumbar spine. Qualitative CSF flow was characterized by neuroradiologists as present or absent., Results: All 18 patients demonstrated CSF flow from the outlets of the fourth ventricle down to the sacrum with no evidence of obstruction. One of these patients, after disease progression, subsequently showed obstruction of CSF flow. No patient required a nuclear medicine study to assess CSF flow prior to initiation of infusions. Fourteen patients have received infusions to date, and none has had neurological toxicity., Conclusions: CSF flow including the fourth ventricle and the total spine can be assessed noninvasively with phase-contrast MRI sequences. Advantages over nuclear medicine studies include avoiding both an invasive procedure and radiation exposure.

Background: The treatment for childhood intracranial ependymoma includes maximal surgical resection followed by involved-field radiotherapy, commonly in the form of intensity-modulated radiation therapy (IMRT). Proton-beam radiation therapy (PRT) is used at some centers in an effort to decrease long-term toxicity. Although protons have the theoretical advantage of a minimal exit dose to the surrounding uninvolved brain tissue, it is unknown whether they have the same efficacy as photons in preventing local recurrence., Methods: A retrospective review of medical records from September 2000 to April 2013 was performed. Seventy-nine children with newly diagnosed localized intracranial ependymomas treated with either IMRT (n = 38) or PRT (n = 41) were identified, and progression-free survival (PFS) was analyzed with Kaplan-Meier and Cox multivariate analyses., Results: The median age at diagnosis was 3.7 years for all patients (range, 0.4-18.7 years). There were 54 patients with infratentorial tumors (68% of the total population). Patients treated with PRT were younger (median age, 2.5 vs 5.7 years; P = .001) and had a shorter median follow-up (2.6 vs 4.9 years; P < .0001). Gross total resection (GTR) was achieved in 67 patients (85%) and was more frequent in the PRT group versus the IMRT group (93% vs 76%; P = .043). The 3-year PFS rates were 60% and 82% with IMRT and PRT, respectively (P = .031)., Conclusions: Children with localized ependymomas treated with PRT have a 3-year PFS rate comparable to that of children treated with IMRT. This analysis suggests that local control is not compromised by the use of PRT. The data also support GTR as the only prognostic factor for PFS. Cancer 2017;123:2570-78. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

Objective: Diffuse intrinsic pontine gliomas (DIPGs) are highly aggressive tumors and have a poor prognosis. Nearly all patients experience disease progression after definitive treatment, accompanied by severe neurologic deficits and morbidity. Here, we report a series of patients treated with reirradiation for palliation of symptoms., Methods: Six patients received reirradiation for progressive DIPG at MD Anderson Cancer Center from 2007 to 2009. Progression after initial chemoradiation and salvage chemotherapy had been confirmed clinically and by magnetic resonance imaging. Each case was discussed at a multidisciplinary conference before reirradiation., Results: Interval between the initial radiation therapy and reirradiation was 8 to 28 months. The initial radiation therapy dose was 54 to 55.8 Gy. Time to initial progression was 4 to 18 months. All of the patients had further progression on salvage chemotherapy. Reirradiation was given with concurrent chemotherapy to a dose of 20 Gy (n=4) or 18 Gy (n=1); 1 patient withdrew care after a single 2-Gy fraction. Four patients had substantial clinical improvement in symptoms, with improvement in speech (n=3), ataxia (n=3), and swallowing (n=2). Three patients showed renewed ability to ambulate after reirradiation. Four patients had decreased tumor size on posttreatment magnetic resonance imaging. The median clinical progression-free survival time was 5 months. Acute radiation-related toxicities were fatigue (n=2), alopecia (n=2), and decreased appetite (n=1). No grade 3 or 4 toxicities were reported., Conclusions: Reirradiation with chemotherapy may be feasible to improve symptoms and delay progression with minimal toxicity. Patients who are most likely to benefit may be those with prolonged response to initial therapy and a long interval since initial radiation.

Objective: Rosai-Dorfman disease is a rare disorder characterized histologically by lymphatic sinus dilatation due to histiocyte proliferation. Our goal was to describe the CT, MRI, and (18)F-FDG (FDG) PET findings in a series of patients with this diagnosis., Materials and Methods: We retrospectively reviewed the imaging studies of 10 patients with pathologically confirmed Rosai-Dorfman disease who were treated in our institution between January 2004 and December 2007., Results: We found the following areas of general involvement: three intracranial, seven head and neck, and three spinal, with some patients having more than one site. Specific sites of involvement included the following: intracranial meninges, n = 2; pituitary, n = 2; lacrimal gland, n = 1; paranasal sinus, n = 3; neck lymph nodes, n = 6; salivary gland, n = 3; tonsil, n = 1; skin, n = 1; spinal meninges, n = 2; vertebral body, n = 1; and thymus, n = 1. The MRI characteristics of the involved areas were generally T1 isointense, T2 isointense, diffusion isointense to gray matter, and intensely enhancing with gadolinium chelate contrast agents. CT images generally showed the lesions were hyperdense to gray matter and intensely enhancing. FDG PET showed variable uptake, with nodal and lacrimal disease generally being FDG avid and other sites not., Conclusion: Rosai-Dorfman disease has a protean imaging appearance but most frequently presents as neck lymphadenopathy. The disease is frequently multifocal, and a diagnosis in one area should prompt suspicion that other sites may be involved also.

Meningioangiomatosis (MA) is an uncommon brain tumor. The role of imaging techniques is underscored in cases where the tumor location makes resection (or even biopsy) dangerous. We report the case of a child with an MA tumor located deep in the right sylvian fissure. A computed tomography (CT) scan showed calcifications in a highly vascular lesion with surrounding edema. Magnetic resonance spectroscopy (MRS) showed a distinct choline (Cho) peak, which usually suggests a proliferating tumor. Fluorodeoxyglucose positron emission tomography (FDG-PET) showed the lesion lacked hypermetabolic features. These radiological features should put MA in the differential diagnosis.

Imaging of the pediatric brain is challenging. Knowledge of the normal anatomy and appearance of the developing brain at a given age is critical in identifying abnormalities. Brain malformations had been in the domain of the neuropathologist, but with advanced neuroimaging they can be defined in vivo. Phacomatoses have a similar tendency to produce manifestations in the central nervous system and many other tissues. The inborn errors of metabolism are a heterogeneous group of rare diseases with diverse imaging findings. In addition to anatomical magnetic resonance (MR) imaging, metabolic imaging with MR spectroscopy is established in many brain disorders, such as tumors, leukodystrophies, and metabolic conditions. Even though catheter angiography remains the gold standard, MR and computed tomography angiography provide rapid and noninvasive alternatives to evaluate children with vascular lesions. This article presents the classic imaging findings in pediatric neurology, including the commonly seen malformations, metabolic disorders, and trauma in addition to some rarer diseases.

Purpose: To demonstrate the technical feasibility and reliability of a multi-center study characterizing regional levels of the brain metabolite ratios choline (Cho)/creatine (Cr) and myoinositol (MI)/Cr, markers of glial cell activity, and N-acetyl aspartate (NAA)/Cr, a marker of mature neurons, in subjects with AIDS dementia complex (ADC)., Materials and Methods: Using an automated protocol (GE PROBE-P), short echo time spectra (TE = 35 msec) were obtained at eight sites from uniformly prepared phantoms and from three brain regions (frontal white matter, basal ganglia, and parietal cortex) of normal volunteers and ADC and HIV-negative subjects., Results: A random-effects model of the phantom and volunteer data showed no significant inter-site differences. Feasibility of a multi-center study was further validated by detection of significant differences between the metabolite ratios of ADC subjects and HIV-negative controls. ADC subjects exhibited significantly higher Cho/Cr and MI/Cr in the basal ganglia and significantly reduced NAA/Cr and significantly higher MI/Cr in the frontal white matter. These results are consistent with the predominantly subcortical distribution of the pathologic abnormalities associated with ADC., Conclusion: This is the first study to ascertain and validate the reliability and reproducibility of a short echo time (1)H-MRS acquisition sequence from multiple brain regions in a multi-center setting. It should now be possible to examine the regional effects of HIV infection in the brain in a large number of subjects and to study the metabolic effects of new therapies for the treatment of ADC in a clinical trial setting., (Copyright 2003 Wiley-Liss, Inc.)

Study Design: Retrospective., Objectives: To determine the incidence, clinical presentation, diagnostic laboratory values, imaging characteristics, and optimal treatment of hematogenous pyogenic facet joint infections., Summary of Background Data: There are 27 documented cases of hematogenous pyogenic facet joint infections. Data regarding incidence, clinical presentation, diagnosis, and treatment response are incomplete because of the paucity of reported cases., Methods: This is a retrospective study of all cases of hematogenous pyogenic facet joint infection treated at one institution. Data from previous publications were combined with the present series to identify pertinent clinical characteristics and response to treatment., Results: A total of six cases (4%) of hematogenous pyogenic facet joint infection were identified of 140 cases of hematogenous pyogenic spinal infection at our institution. Combining all reported cases reveals the following: The average patient age is 55 years. Ninety-seven percent of cases occur in the lumbar spine. Epidural abscess formation complicates 25% of the cases of which 38% develop severe neurologic deficit. Erythrocyte sedimentation rate and C-reactive protein are elevated in all cases. Staphylococcus aureus is the most common infecting organism. Magnetic resonance imaging is accurate in identifying the septic joint and associated abscess formation. Percutaneous drainage of the involved joint has a higher rate of success (85%) than treatment with antibiotics alone (71%), but the difference is not significant (P = 0.37)., Conclusions: Hematogenous pyogenic facet joint infection is a rare but underdiagnosed clinical entity. Facet joint infections may be complicated by abscess formation in the epidural space or in the paraspinal muscles. Uncomplicated cases treated with percutaneous drainage and antibiotics may fare better than those treated with antibiotics alone. Cases complicated by an epidural abscess and severe neurologic deficit should undergo immediate decompressive laminectomy.

Age-related white matter injury has been recognized increasingly with the improvement of brain imaging technology. Arteriosclerosis and venous collagenosis, which occur with aging, result in a spectrum of white matter changes that range from periventricular to subcortical and deep white matter hyperintensities best seen on T2 weighted magnetic resonance imaging. These white matter changes are associated not only with aging, but with hypertension and silent infarctions. Loss of brain volume and accumulation of iron in putamen occur with normal, healthy aging. This article discusses the imaging appearance of healthy aging and pathological correlates of similar appearing alterations. The imaging findings of the most common neurodegenerative disorders, Alzheimer's and Parkinson's disease, are highlighted.

Magnetic resonance imaging (MRI) is the method of choice to detect cerebral cavernous angiomas. Specifically tailored MRI studies are necessary to evaluate patients with cerebral cavernous angiomas. The patient described here, for whom serial MRIs performed on different scanners falsely suggested rapid disease progression, illustrates the point.

Eight patients with hypertensive encephalopathy from diverse etiologies developed cerebral edema in the vertebrobasilar distribution which resolved after blood pressure was lowered. Parietal occipital edema is a recognized feature of hypertensive encephalopathy. The explanation for this regional pathological variation in hypertensive encephalopathy remains undefined. Some evidence suggests that sympathetic innervation of the anterior cerebral vasculature may be protective, and conversely, the relative lack of sympathetic innervation in the vertebrobasilar vasculature may predispose the parietal occipital region to the development of cerebral edema in hypertensive encephalopathy.

Purpose: To report the MR and CT findings in a hereditary disease, infantile-onset spinocerebellar ataxia (IOSCA)., Methods: We studied the brains of 17 patients with infantile-onset spinocerebellar ataxia with CT and/or MR to determine the presence of cerebellar and brain stem atrophy and parenchymal lesions., Results: Cerebellar cortical atrophy was seen in 13 patients. The degree of atrophy correlated with increasing age and clinical deterioration. Brain stem atrophy was seen in 8 patients. It was never severe, and the basis pontis was not flattened even in the most severe cases. Hyperintense lesions were noted within the white matter of cerebellum, in the dentate nuclei, and in the middle cerebellar peduncles in 3 patients. The upper cervical cord was seen in 9 patients and showed mild to moderate atrophy in 4. The basal ganglia and cerebral hemispheres were normal, except in 2 patients transient cortical and subcortical lesions developed during episodes of status epilepticus; mild cortical brain atrophy subsequently developed., Conclusion: The brain MR and CT findings of patients with infantile-onset spinocerebellar ataxia correspond to the neuropathologic entities of cerebellar cortical atrophy, olivopontocerebellar atrophy, and spinocerebellar atrophy. The appearance of the findings followed a uniform time sequence from cerebellar cortical atrophy in the early stage of the disease to olivopontocerebellar atrophy and spinocerebellar atrophy in the later stage. The severity of atrophy correlated with clinical deterioration.

We describe a case of duplication of the left internal carotid artery from a point 1 cm distal to the origin to the proximal petrous segment where the vessel reunites. Duplication and fenestration of the internal carotid artery are discussed. A review of embryologic development is presented. Identification of these entities is important, especially in patients who require surgical intervention involving the internal carotid artery.

A 52-year-old man developed a severe anaphylactic reaction after a wasp sting. Slurred speech and left hemiparesis were noted a few hours later. Three-and-one-half weeks later, he became acutely obtunded and quadriparetic. Angiographic studies demonstrated complete and near-complete occlusions of the right and left internal carotid arteries, respectively. A mechanism is suggested for delayed ischemic stroke after wasp sting anaphylaxis that involves cerebrovascular sympathetic innervation.

A 38-year-old man, stung repeatedly by wasps on the left face and neck, had his left internal carotid artery occluded 2 days later. A mechanism for ischemic stroke involving the sympathetic innervation of cerebral vasculature is suggested.

Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive childhood disorder characterized by severe motor and mental deterioration. The disease has been divided into 3 main types and further subdivided into several subtypes based on age of onset and symptoms. Initial clinical findings and magnetic resonance imaging (MRI) with several follow-up scans are presented to identify the order and extent of white matter involvement and developing brain atrophy in a child with the floppy infant variant of Krabbe disease. When the patient's clinical condition proceeded to stage 2, MRI disclosed severe involvement of the deep white matter around the atria and posterior limbs of the internal capsules. At the same time there was progression of normal myelination around the frontal horns. At age 32 months, the patient's clinical condition proceeded to stage 3; she did not interact with her environment. MRI revealed a significant decrease of white matter volume, generalized atrophy, and abnormal high signal in all white matter areas except the anterior limbs of the internal capsules. At the same time the volume of the central gray nuclei was decreased and also demonstrated abnormal high signal. Despite its sensitivity, MRI could not differentiate the findings of this variant of Krabbe disease from the classic form; therefore, subclassifications of Krabbe disease should be made on clinical grounds because they cannot be distinguished by biochemical or radiologic (MRI) criteria.

The exponential growth in the number of computed tomography scanners in the United States between 1975 and 1977 was associated with a transient increase (11.9 and 14.4% for men and women, respectively) in annual crude mortality rates for primary malignant brain tumor from 1976 through 1978. This transient increase in mortality appears to have been an artifactual epiphenomenon associated with the introduction of a new technology.

Six patients presenting with new neurological deficits underwent magnetic resonance imaging (MRI) that displayed mass lesions leading to diagnoses of tumor or abscess. Biopsy revealed demyelinating lesions.

We evaluated the images of 60 carotid artery bifurcations in 31 patients suspected to have carotid artery disease who underwent invasive carotid angiography and combined two-dimensional, phase-sensitive and a gradient-echo magnetic resonance angiography. The phase scans consisted of seven serial projections that were obtained at 20 degrees intervals (11.0 minutes) around the carotid bifurcation; the gradient-echo (GRASS) scans were composed of 11 axial images (2.4 minutes) acquired through the bifurcation. The two magnetic resonance angiographic techniques yielded complementary pieces of information and were used together to compare magnetic resonance angiography with invasive angiography. Comparison of magnetic resonance and invasive angiograms of the 60 carotid arteries shows that the sensitivity (86%) and specificity (92%) of the magnetic resonance angiographic techniques we used to diagnose clinically significant carotid stenosis approach but do not reach those of invasive angiography.