The usefulness of the O-MAR algorithm in MRI skull base assessment to manage cochlear implant-related artifacts.

Objective: To assess artifact size and MRI visibility when applying the "Orthopedic-Metal Artifact Reduction" (O-MAR) algorithm for cochlear implant (CI) scanning. Methods: Two volunteers were submitted to 1.5 T MRI with an Ultra 3D CI receiver stimulator placed on their head. Four angular CI orientations were adopted: 90, 120, 135 and 160 degrees. Volunteers were scanned in each condition using T1w and T2w TSE sequences, as well as O-MAR sequences, in both axial and coronal planes. Quantitative comparisons were made of signal void and penumbra extent. Additionally, qualitative evaluations of global image quality, MRI readability with respect to 12 anatomical structures and visibility through the penumbra were undertaken. Results: After application of the O-MAR protocol, the radius of the signal void reduced from 50.76 mm to 45.43 mm and from 49.22 mm to 40.15 mm on T1w and T2w TSE axial sequences, respectively (p < 0.05). Qualitatively, sequences acquired with O-MAR produced better outcomes in terms of image quality and anatomical depiction. Despite the area of the penumbra being increased for the O-MAR protocol, visibility through penumbra was improved. Conclusions: Application of O-MAR may provide a complementary strategy to those already in use to obtain diagnostically useful MRI examinations in the presence of a CI, especially in case of skull base diseases requiring MRI monitoring.

Case report: Multiple brain intravascular papillary endothelial hyperplasia: incidence, diagnostic challenges, and management approach.

Multiple hemorrhagic brain lesions are mainly diagnosed based on clinico-radiological features integrated with histological data. Intravascular papillary endothelial hyperplasia (IPEH), or Masson's tumor, is a very rare entity, particularly when localized in the brain. In this study, we describe a case of multiple recurrent brain IPEHs and provide details on the diagnostic phase, therapeutic approaches, and related challenges. A 55-year-old woman presented with a relapsing neurological deficit. Brain magnetic resonance imaging (MRI) revealed a hemorrhagic right frontal-parietal lesion. When new neurological symptoms occurred, subsequent MRI scans detected more bleeding cerebral lesions. She underwent a series of single hemorrhagic lesion debulking. For any samples that underwent histopathological examination, the first results were not informative; the second and the third results revealed hemangioendothelioma (HE); and the fourth results led to the IPEH diagnosis. Interferon alpha (IFN-α) and subsequently sirolimus were prescribed. Both were well tolerated. Clinical and radiological features remained stable 43 months after starting sirolimus therapy and 132 months after the first diagnosis. To date, 45 cases of intracranial IPEH have been reported, mostly as single lesions without parenchymal location. They are usually treated by surgery and sometimes by radiotherapy upon recurrence. Our case is notable for two main reasons: because of the consecutive recurrent multifocal exclusively cerebral lesions and the therapeutic approach we used. Based on multifocal brain recurrence and good performance, we propose pharmacological therapy, including IFN-α and sirolimus, to stabilize IPEH.

Response assessment in paediatric intracranial ependymoma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group.

Response criteria for paediatric intracranial ependymoma vary historically and across different international cooperative groups. The Response Assessment in the Pediatric Neuro-Oncology (RAPNO) working group, consisting of an international panel of paediatric and adult neuro-oncologists, neuro-radiologists, radiation oncologists, and neurosurgeons, was established to address both the issues and the unique challenges in assessing the response in children with CNS tumours. We established a subcommittee to develop response assessment criteria for paediatric ependymoma. Current practice and literature were reviewed to identify major challenges in assessing the response of paediatric ependymoma to clinical trial therapy. For areas in which data were scarce or unavailable, consensus was reached through an iterative process. RAPNO response assessment recommendations include assessing disease response on the basis of changes in tumour volume, and using event-free survival as a study endpoint for patients entering clinical trials without bulky disease. Our recommendations for response assessment include the use of brain and spine MRI, cerebral spinal fluid cytology, neurological examination, and steroid use. Baseline postoperative imaging to assess for residual tumour should be obtained 24-48 h after surgery. Our consensus recommendations and response definitions should be prospectively validated in clinical trials.

Response assessment in diffuse intrinsic pontine glioma: recommendations from the Response Assessment in Pediatric Neuro-Oncology (RAPNO) working group.

Optimising the conduct of clinical trials for diffuse intrinsic pontine glioma involves use of consistent, objective disease assessments and standardised response criteria. The Response Assessment in Pediatric Neuro-Oncology 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. A working group was formed specifically to address response assessment in children and young adults with diffuse intrinsic pontine glioma and to develop a consensus on recommendations for response assessment. Response should be assessed using MRI of brain and spine, neurological examination, and anti-inflammatory or antiangiogenic drugs. Clinical imaging standards are defined. As with previous consensus recommendations, these recommendations will need to be validated in prospective clinical trials.