Advanced MRI imaging techniques in pediatric brain tumors.

There is a diverse array of pediatric brain tumors with considerable associated morbidity. Like adult brain tumors, MRI serves as the primary imaging modality for pediatric brain tumors. In addition to standard sequences, more advanced MRI techniques can enhance the precision of diagnosis and assist in prognostication, and treatment planning. This paper discusses these various advanced techniques categorizing them into those that assist in identifying tissue characteristics, and those that evaluate the functional impact of tumors to aid in treatment planning.

IDH mutation, glioma immunogenicity, and therapeutic challenge of primary mismatch repair deficient IDH-mutant astrocytoma PMMRDIA: a systematic review.

In 2021, Suwala et al. described Primary Mismatch Repair Deficient IDH-mutant Astrocytoma (PMMRDIA) as a distinct group of gliomas. In unsupervised clustering, PMMRDIA forms distinct cluster, separate from other IDH-mutant gliomas, including IDH-mutant gliomas with secondary mismatch repair (MMR) deficiency. In the published cohort, three patients received treatment with an immune checkpoint blocker (ICB), yet none exhibited a response, which aligns with existing knowledge about the decreased immunogenicity of IDH-mutant gliomas in comparison to IDH-wildtype. In the case of PMMRDIA, the inherent resistance to the standard-of-care temozolomide caused by MMR deficiency is an additional challenge. It is known that a gain-of-function mutation of IDH1/2 genes produces the oncometabolite R-2-hydroxyglutarate (R-2-HG), which increases DNA and histone methylation contributing to the characteristic glioma-associated CpG island methylator phenotype (G-CIMP). While other factors could be involved in remodeling the tumor microenvironment (TME) of IDH-mutant gliomas, this systematic review emphasizes the role of R-2-HG and the subsequent G-CIMP in immune suppression. This highlights a potential actionable pathway to enhance the response of ICB, which might be relevant for addressing the unmet therapeutic challenge of PMMRDIA.

Diagnostic Performance of a Staged Pathway for Imaging Acute Appendicitis in Children.

INTRODUCTION: The objective of this work is to assess the performance of our staged diagnostic pathway in the evaluation of suspected appendicitis cases in children. The pathway consisted of clinical assessment by the emergency physician, performing initial ultrasound (US), consultation, and clinical reevaluation by the surgery team followed by a repeat focused US scan in inconclusive cases. Computed tomography (CT) was limited to cases where the repeat US remained inconclusive and the clinical reassessment indicated persistent concerns for appendicitis. METHOD: Retrospective review of the electronic medical records of 206 consecutive children who presented to our emergency department with acute abdominal pain and underwent US examination for suspected appendicitis. The imaging findings, management plan, and surgical outcome (in those who underwent surgery) were reviewed. The diagnostic performance of the initial US, repeat US, and the full imaging protocol were evaluated including the negative appendectomy rate (NAR) and the number of CT scans performed. RESULTS: Of the 206 cases, 73 (35.4%) had appendicitis. Computed tomography was performed in 9 (4.3%) of 206 cases. The US/CT ratio was 23:1. Our approach showed a diagnostic accuracy of 95.6% (197/206), sensitivity of 97.3% (73/75), specificity of 93.7% (124/133), positive predictive value of 89.0% (73/82), and negative predictive value of 98.7% (82/95). The NAR was 2.7% (2/72). The accuracy of the protocol is higher than that of the initial US alone (61.2%; 126/206) and that of the repeat US (84.2%; 16/19). CONCLUSION: The strategy of repeating limited focused US followed by CT scan in cases that remain inconclusive has good diagnostic accuracy and reasonable NAR and decreases the number of CT scans.

Epidemiology of neonatal stroke: A population-based study.

OBJECTIVE: The goal of this study was to obtain population-based data on the incidence, clinical presentation, management, imaging features, and long-term outcomes of patients with all types of neonatal stroke (NS). METHODS: Full-term neonates with NS born between January 2007 and December 2013 were identified through the Nova Scotia Provincial Perinatal Follow-up Program Database. Perinatal data and neonatal course were reviewed. Neurodevelopmental outcomes were assessed at 18 and 36 months of age using standardized testing. RESULTS: Twenty-nine neonates with NS were identified during the study period, giving an incidence of 47 per 100,000 live births in Nova Scotia. Arterial ischemic stroke was the most common stroke type (76%), followed by neonatal hemorrhagic stroke (17%), then cerebral sinovenous thrombosis (7%). The majority of neonates presented with seizures (86%) on the first day of life (76%). At 36 months of age, 23 (79%) of the children had a normal outcome, while 3 (10%) were diagnosed with cerebral palsy (2 with neonatal arterial stroke and one with neonatal hemorrhagic stroke) and 3 (10%) had recurrent seizures (1 patient from each stroke subtype group). CONCLUSION: The incidence of NS in Nova Scotia is higher than what has been reported internationally in the literature. However, the neurodevelopmental outcomes at 3 years of age are better. Further studies are required to better understand the reasons for these findings.

Resolution of Middle Fossa Arachnoid Cyst after Minor Head Trauma - Stages of Resolution on MRI: Case Report and Literature Review.

Arachnoid cysts (ACs) are frequently encountered in pediatric neurosurgical practice. Their natural history and optimum treatment are not well determined. The authors describe a resolution of asymptomatic middle fossa AC after trivial head trauma in a 7-year-old child. Intracystic bleeding was noticed on interval MRI. Serial MRI follow-up demonstrates stages of resolution of the AC that did not require surgical intervention. Few cases of nonsurgical AC disappearance have been reported, much fewer with trauma as a triggering factor. Here, we present the stages of resolution in images.

Doppler Parameters of the Hepatic Artery as Predictors of Graft Status in Pediatric Liver Transplantation.

OBJECTIVE: The purpose of this article is to determine whether hepatic artery (HA) Doppler parameters can be used to predict pediatric liver graft status in the immediate postoperative (< 10 days) period and in the first year after transplant. MATERIALS AND METHODS: A retrospective review of the liver transplant database was performed to review operative, clinical, laboratory, histopathologic, and ultrasound findings at three time points after surgery: 3 days, 3 months, and 1 year. The association between HA velocity and resistive index (RI) with graft status was assessed. RESULTS: Of 120 children (54 girls and 66 boys; mean age, 3 years 2 months) enrolled, 70 had satisfactory graft status at the 1-year follow-up examination. HA velocity of 50-200 cm/s at 3 days was associated with normal graft status during the immediate postoperative period (p = 0.003), at 3 months (p = 0.0653), and at the 1-year follow-up examination (p = 0.0268). Vascular and biliary complications in the immediate postoperative period were more frequent at an HA velocity of 201-300 cm/s (p = 0.0024). There was a significant association between RI at 3 days and graft status in the immediate postoperative period (p = 0.0308), with an RI less than 0.5 associated with vascular complications (p = 0.0116). CONCLUSION: An RI less than 0.5 is associated with vascular complications. An HA velocity of 50-200 cm/s and an RI of 0.5-0.8 are associated with normal graft status in children within the first year after transplant. Values outside this range, or in this range along with a constellation of other ultrasound findings and clinical status, support the initiation of additional more-specific investigations that may help in early treatment to prevent complications.

Atypical Teratoid Rhabdoid Tumor Diagnosis after Partial Resection of Dysembryoplastic Neuroepithelial Tumor: Case Report and Review of the Literature.

Dysembryoplastic neuroepithelial tumors (DNETs) are generally considered benign, slow-growing epilepsy-associated lesions. While rare cases of malignant transformation of DNET to high-grade glial tumors have been reported, to our knowledge there have been no reports of transformation/emergence of DNET to atypical teratoid rhabdoid tumor (AT/RT), a highly aggressive embryonal brain tumor. Here, we report the case of an 8-year-old boy who presented with an incidental finding of a small right insular lesion which grew slowly over 3 years. The patient first underwent surgery with subtotal tumor resection at age 11. Pathology was consistent with DNET. Following surgery, further tumor growth was evident, requiring fractionated radiotherapy and eventually chemotherapy, but continued tumor growth was witnessed. Three years after radiation, imaging showed dramatic further tumor growth, and the patient underwent a second debulking surgery. The pathology revealed a malignant tumor with BAF47-negative cells, suggestive of AT/RT. This report adds to our knowledge about the poorly understood behavior and natural history of DNETs and emphasizes the importance of lifelong clinical and neuroimaging follow-up of these lesions.

Bowel Sonography and MR Enterography in Children.

OBJECTIVE: The objective of this study was to assess the diagnostic agreement between bowel sonography and MR enterography in children with suspected or confirmed inflammatory bowel disease (IBD). SUBJECTS AND METHODS: We prospectively studied 33 children undergoing clinically indicated MR enterography. Bowel sonography was performed within 2 hours before MR enterography. The reliability of each modality was assessed by computing the interreader kappa agreement on nine inflammatory markers in eight bowel segments and the interreader intraclass correlation coefficients (ICC) in each bowel segment. The agreement between both modalities in each bowel segment was also calculated using the Kendall coefficient of concordance (KCC) in addition to the sensitivity and specificity of sonography using those of MR enterography as the reference standard. RESULTS: Sonographic readings are substantially reliable in the colon and terminal and distal ileum (ICC = 0.79-0.88) but are highly unreliable in the mid and proximal small bowel. MR enterography has moderate to almost perfect reliability for all bowel segments (ICC = 0.43-0.96). Sonography was in substantial agreement with MR enterography in most of the large bowel (KCC = 0.67-0.83) and terminal and distal ileum (KCC = 0.75) and in moderate agreement in the remaining bowel segments (KCC = 0.45-0.48). Sonographic findings are specific for disease using MR enterography as the reference standard in all bowel segments (0.83-1.00), but sensitivity markedly varies according to disease location. CONCLUSION: Sonography is highly specific and shows substantial agreement with MR enterography in detecting inflammatory and damage changes in the colon and terminal and distal ileum, the segments most likely to be affected by IBD. Therefore, sonography can be a good complement to MR enterography in evaluations of patients with known or suspected IBD, particularly if MR enterography access is limited.

Management of infiltrating spinal epidural angiolipoma.

Angiolipomas of the spine are rare benign tumors commonly presenting with compressive myelopathy. The present report describes a case of spinal angiolipoma with thoracic mediastinal extension in a 50-year-old woman. She presented with a long-standing history of mid-back pain with progressive lower extremities weakness. An MRI showed a heterogeneously enhancing mass located in the posterior epidural space of the thoracic spine with mediastinal extension. Histopathological examination demonstrated features consistent with spinal angiolipoma. This report emphasizes the diagnosis and therapeutic management options of infiltrating spinal angiolipomas.

Medulloblastoma invading the transverse sinus: case report.

Medulloblastoma is a highly malignant brain tumor of childhood. Although craniospinal dissemination within the subarachnoid space is common, invasion of the dural sinuses is rare. Here, the authors report on a 15-year-old girl who presented with a right cerebellar mass, obstructive hydrocephalus, and radiographic evidence of tumor invasion into the right transverse-sigmoid sinus junction. The patient underwent posterior fossa craniotomy, gross-total resection of the intraparenchymal component of the right cerebellar tumor, and coagulation of the tumor invading the transverse sinus. After pathological confirmation of anaplastic medulloblastoma, the patient underwent craniospinal radiation therapy and high-dose chemotherapy. At 2 years posttreatment, the child was neurologically intact with no radiographic evidence of residual disease or recurrence. The implications for disease prognosis and management are discussed.

The premature brain: developmental and lesional anatomy.

INTRODUCTION: Neurodevelopmental outcome in prematures who suffer from a neonatal brain injury depends on the lesion itself, and on how the lesion interferes with the still developing functional anatomy. METHODS: Most of the neuronal migration is completed by midgestation. The second part of the gestation corresponds to the development of the connectivity and sulcation, of the maturation of the oligodendrocytic lineage and of the microglia, and of the vascular bed in the parenchyma beyond the germinal matrix. RESULTS: In this paper, the main processes of the developmental anatomy of the premature brain are reviewed, and are correlated with the findings in a prospective series of 105 premature infants born between 24 and 32 weeks of gestation, and serially examined with MR imaging at birth, at term-equivalent age, at 2 years, and at 4 years. Special emphasis was placed (1) on the intraventricular hemorrhage because of the resulting destruction of the germinal matrix and its impact on the late cellular production, (2) on the periventricular venous hemorrhagic infarction because of the selective destruction of the intermediate zone which is associated, and (3) on the apparently perivenous punctate lesions of the white matter because they involve the intermediate zone also, because they have no convincing explanation yet, and because the microglia seems to be associated with their pathogenesis. CONCLUSION: These deep venous injuries appear to preserve the subplate zone, which is likely to be a significant element to consider in the perspective of the neurodevelopmental outcome.

Descriptive epidemiological analysis, MRI signals intensity and histopathological correlations of meningiomas.

OBJECTIVES: To present our experience in operated meningioma cases regarding their prevalence, anatomical location, multiplicity, presenting signs and symptoms, and the possible correlation between MRI signal intensity and histological grades to set criteria for radio-pathological diagnosis. METHODS: In this retrospective study, operated meningioma cases in the Department of Neurosurgery, Jordan University Hospital (JUH), Amman, Jordan between January 1997 and January 2007 were reviewed. Our study included 90 cases, and their medical records, histopathological reports, and neuroimages were analyzed thoroughly. RESULTS: Meningioma was more common in females than males with a ratio of 2.2:1. Para-sagittal meningiomas were the most common (23.3%). Multiple intracranial meningiomas were found in 4.4% of the cases. Most cases were of benign histopathology and exhibited iso-intense signals on T1 and T2, and appeared with hyper-intense signals on FLAIR with vivid enhancement. CONCLUSION: The prevalence of meningioma among genders and its anatomical location at JUH corresponds to the published medical literature worldwide. There was no correlation between signal intensities (as seen on T1WI, T2WI, and FLAIR sequences), enhancement pattern on one side, and histological grades on the other side.