MR Imaging of Pediatric Neuroblastoma: Is Gadolinium Enhancement Necessary for Evaluation of Image-Defined-Risk Factors?

Background: Pre-treatment stratification and outcomes of neuroblastoma patients often depend on the assessment of image-defined risk factors (IDRFs) on MR Imaging, usually using Gadolinium-contrast materials which are cautioned in pediatrics. We aimed to address whether gadolinium contrast-enhanced sequences are necessary to identify the presence/absence of IDRFs. Methods: Patients with neuroblastoma with MR imaging were retrospectively identified from 2005 to 2021. Ninety confirmed IDRFs were evaluated in 23 patients. Corresponding MR studies were anonymized, randomized, and independently evaluated by 3 fellowship-trained pediatric radiologists. Each radiologist assessed the studies twice. At the first reading, all enhanced sequences were omitted, while in the second reading, the full study with enhanced sequences were included. Consensus reading was obtained among readers. Inter- and intra-rater agreements using Kappa statistics (κ) as well as the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of non-enhanced MR in assessing IDRFs with respect to enhanced MR were calculated. Results: There were substantial (ĸ: 0.64-0.73) intra-reader agreements, and moderate to substantial (ĸ: 0.57-0.62) inter-reader agreements among radiologists in identifying IDRFs using non-enhanced MR. Non-enhanced MR had a sensitivity of 87.8% (95% CI [79-94]), specificity of 93% (89-96), PPV of 82.3 (73-89), NPV of 95.4 (92-98), and accuracy of 91.6 (88-94) in identifying IDRFs. However, 5/23 patients (21.7%) had a change in staging with the inclusion of contrast sequences. Conclusion: Although contrast sequences have a role in IDRF assessment, the majority can be adequately assessed on MR without gadolinium-contrast enhancement. Validation in a larger cohort is an important next step.

Systematic review of diffuse hemispheric glioma, H3 G34-mutant: Outcomes and associated clinical factors.

Background: A comprehensive review and description of the clinical features that impact prognosis for patients with diffuse hemispheric glioma, H3 G34-mutant (G34-DHG) is needed. Understanding survival and prognostic features is paramount for clinical advancements and patient care. Methods: PubMed, Embase, and Google Scholar were searched for English articles published between January 1, 2012 and June 30, 2021. Eligible studies included patient(s) of any age diagnosed with an H3 G34-mutant brain tumor with at least one measure of survival or progression. Patient-level data were pooled for analyses. This study was prospectively registered in PROSPERO (CRD42021267764) and Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Results: Twenty-seven studies met the criteria with a total of 135 patients included. Median age at diagnosis was 15.8 years (interquartile range [IQR]: 13.3-22.0) with 90% having localized disease. Co-occurring alterations included ATRX mutation in 93%, TP53 mutation in 88%, and MGMT promoter methylation in 70%. Median time-to-progression was 10.0 months (IQR: 6.0-18.0) and median overall survival was 17.3 months (95% CI: 15.0 to 22.9). The median time from progression to death was 5.0 months (IQR: 3.0-11.7). Factors associated with survival duration were age, as patients ≥18 y/o demonstrated longer survival (hazard ratio [HR] =2.05, 95% CI: 1.16 to 3.62), and degree of upfront resection, as near or gross-total resection demonstrated longer survival compared to those with less than near-total resection (HR = 3.75, 95% CI: 2.11 to 6.62). Conclusion: This systematic review highlights available clinical data for G34-DHG demonstrating poor outcomes and important prognostic features, while serving as a baseline for future research and clinical trials.

Response assessment in paediatric high-grade glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group.

Response criteria for paediatric high-grade glioma vary historically and across different cooperative groups. The Response Assessment in Neuro-Oncology working group developed response criteria for adult high-grade glioma, but these were not created to meet the unique challenges in children with the disease. The Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group, consisting of an international panel of paediatric and adult neuro-oncologists, clinicians, radiologists, radiation oncologists, and neurosurgeons, was established to address issues and unique challenges in assessing response in children with CNS tumours. We established a subcommittee to develop response assessment criteria for paediatric high-grade glioma. Current practice and literature were reviewed to identify major challenges in assessing the response of paediatric high-grade gliomas to various treatments. For areas in which scientific investigation was scarce, consensus was reached through an iterative process. RAPNO response assessment recommendations include the use of MRI of the brain and the spine, assessment of clinical status, and the use of corticosteroids or antiangiogenics. Imaging standards for brain and spine are defined. Compared with the recommendations for the management of adult high-grade glioma, for paediatrics there is inclusion of diffusion-weighted imaging and a higher reliance on T2-weighted fluid-attenuated inversion recovery. Consensus recommendations and response definitions have been established and, similar to other RAPNO recommendations, prospective validation in clinical trials is warranted.

320-row CT transcatheter aortic valve replacement planning with a single reduced contrast media bolus injection.

OBJECTIVE: To reduce the iodine load required for CT Transcatheter Aortic Valve Replacement (TAVR) planning on a 320-row scanner by acquiring the two CT TAVR steps (ECG-gated aortic root CTA and non-gated aorto-ilio-femoral CTA) within a single contrast media bolus injection. METHODS: 50 consecutive patients (82.6±6.9 years; 56% female) were prospectively enrolled and underwent a TAVR planning using a 320-row CT, with ECG-gated aortic root CTA immediately followed by a non-gated aorto-iliac acquisition, all within a single bolus of 40-70mL of Iohexol 350mgI/mL. The Iodine load, image quality, SNR, CNR and radiation dose were compared using a Mann-Whitney test to that of 24 consecutive patients (84.3±4.8 years, 58% female) previously imaged on a 64-row scanner with a conventional two-step protocol. RESULTS: Iodine load was reduced by 44%. All examinations were of diagnostic quality, with improvement of the aortic root CTA image quality (4.9±0.3 versus 4.6±0.5, p<0.01) and a non-significant decrease of the aorto-iliac CTA image quality (4.7±0.6 versus 4.9±0.3, p = 0.07). SNR and CNR were significantly improved in the aortic root CTA (14.0±5.3 and 10.4±4.5 versus 10.3±4.2 and 6.8±3.3, p<0.01 for both) and non-significantly higher in the aorto-iliac CTA (16.5±8.0 and 14.1±7.9 versus 14.7±5.5 and 12.5±5.0, p = 0.42 and p = 0.66). Total radiation dose was reduced by 32%. CONCLUSION: 320-row CT scanner enables a 44% reduction of iodine load in TAVR planning, while maintaining excellent aorto-ilio-femoral arterial enhancement and lowering radiation dose.

Arachnoid cysts with spontaneous intracystic hemorrhage and associated subdural hematoma: Report of management and follow-up of 2 cases.

Arachnoid cysts are one of the most frequently encountered intracranial space-occupying lesions in daily neurosurgery and neuroradiology practice. Majority of arachnoid cysts, particularly those of smaller sizes, have a benign uneventful lifetime course. Certain symptoms may indicate serious complications related to underlying arachnoid cysts. Hemorrhage is one of the most fearsome complications of arachnoid cysts and almost all reported cases in the literature have undergone surgical correction. In this study, we aimed to present clinical and radiologic follow-up findings in two adult cases of intracranial arachnoid cyst with spontaneous intracystic hemorrhage and associated subdural hematoma, one of which was successfully treated conservatively. In addition, we broadly summarized and discussed pertinent studies in the English literature.

Differential patterns of metastatic dissemination across medulloblastoma subgroups.

OBJECTIVE Metastatic dissemination is a major treatment challenge and cause of death in patients with medulloblastoma. However, the influence of molecular biology on the pattern of metastatic dissemination at diagnosis is not known. In this study, the authors sought to define the location, pattern, and imaging characteristics of medulloblastoma metastases across subgroups at diagnosis. METHODS A consecutive cohort of patients with metastatic medulloblastoma at The Hospital for Sick Children and the University Hospital Motol, who underwent up-front MRI of the craniospinal axis, was assembled and allocated to subgroups using NanoString limited gene-expression profiling. Radiological characteristics (including location, morphology, size, diffusion restriction, and contrast enhancement) were discerned through a retrospective review. RESULTS Forty metastatic medulloblastomas were identified with up-front neuroimaging of the craniospinal axis: 5 sonic hedgehog (SHH), 16 Group 3, and 19 Group 4 metastases. Significant subgroup-specific differences were observed, particularly with respect to tumor location, size, and morphology. Group 3 metastases were most frequently laminar compared with a more nodular pattern in Group 4 (14 of 16 in Group 3 vs 8 of 19 in Group 4; p = 0.0004). Laminar metastases were not observed in patients with SHH medulloblastoma. Suprasellar metastases are highly specific to Group 4 (p = 0.016). Two of the 5 SHH cases had multifocal lesions in the cerebellum, raising the possibility that these were in fact synchronous primary tumors and not true metastases. A minority of patients with Group 4 metastases harbored metastatic deposits that did not enhance on MRI after contrast administration, often in patients whose primary tumor did not enhance. CONCLUSIONS The location, morphology, and imaging characteristics of metastatic medulloblastoma differ across molecular subgroups, with implications for diagnosis and management. This suggests that the biology of leptomeningeal dissemination differs among medulloblastoma subgroups.