Cerebellar mutism syndrome caused by bilateral cerebellar hemorrhage in adults: a case report and review of the literature.

Cerebellar mutism syndrome (CMS) is a frequent complication of surgical intervention on posterior fossa in children. It has been only occasionally reported in adults and its features have not been fully characterized. In children and in young adults, medulloblastoma is the main reason for neurosurgery. A single case of postsurgical CMS is presented in an adult patient with a cerebellar hemorrhage and a systematic review of the published individual cases of CMS in adults was done. Literature review of individual cases found 30 patients, 18/30 (60%) males, from 20 to 71 years at diagnosis. All but one case was post-surgical, but in one of the post-surgical cases iatrogenic basilar artery occlusion was proposed as cause for CMS. The causes were: primary tumors of the posterior fossa in 16/22 (72.7%) metastasis in 3/30 (10%), ischemia in 3/30 (10%) cerebellar hemorrhage in 3/30 (10%), and benign lesions in 2/30 (6.7%) patients. 8/30 patients (26.7%) were reported as having persistent or incomplete resolution of CMS within 12 months. CMS is a rare occurrence in adults and spontaneous cerebellar hemorrhage has been reported in 3/30 (10%) adult patients. The generally accepted hypothesis is that CMS results from bilateral damage to the dentate nucleus or the dentate-rubro-thalamic tract, leading to cerebro-cerebellar diaschisis. Several causes might contribute in adults. The prognosis of CMS is slightly worse in adults than in children, but two thirds of cases show a complete resolution within 6 months.

The Contribution of Vessel Wall Magnetic Resonance Imaging to the Diagnosis of Primary and Secondary Central Nervous System Vasculitis.

BACKGROUND: To describe high-resolution brain vessel wall MRI (VW-MRI) patterns and morphological brain findings in central nervous system (CNS) vasculitis patients. METHODS: Fourteen patients with confirmed CNS Vasculitis from two tertiary centers underwent VW-MRI using a 3T scanner. The images were reviewed by two neuroradiologists to assess vessel wall enhancement characteristics and locations. RESULTS: Fourteen patients were included (six females; average age 48 ± 19 years). Diagnoses included primary CNS vasculitis (PCNSV) in six patients and secondary CNS vasculitis (SCNSV) in eight, half of which were infection-related. Thirteen patients showed vessel wall enhancement, which was intense in eleven patients (84.6%) and concentric in twelve (92.3%), affecting the anterior circulation in nine patients (69.2%), posterior in two patients (15.4%), and both circulations in two patients (15.4%). The enhancement patterns were similar across different CNS vasculitis types. DWI changes corresponded with areas of vessel wall enhancement in 77% of patients. Conclusions: CNS vasculitis is often associated with intense, concentric vessel wall enhancement in VW-MRI, especially in the anterior circulation. The consistent presence of DWI alterations in affected territories suggests a possible link to microembolization or hypoperfusion. These imaging findings complement parenchymal brain MRI and MRA/DSA data, potentially increasing the possibility of a clinical diagnosis of CNS vasculitis.

Persistent intracranial steno-occlusion from calcified embolism: a treatment challenge.

INTRODUCTION: Calcified arterial cerebral embolism is a rare occurrence among large and medium vessel occlusions causing ischemic stroke and its diagnosis and treatment is a challenge. The sources of calcified embolism might be a calcific atheroma from the aortic arch and carotid artery, but also heart valve disease has been reported in the literature. Calcified embolism is frequently simultaneous on multiple vascular territories. The prognosis of patients is usually poor, including patients treated by using endovascular thrombectomy (EVT) and this diagnosis could be easily missed in the acute phase. In addition, the optimal secondary prevention has not been yet fully stated. METHODS: We are presenting two cases of acute stroke due to calcified embolism in the middle cerebral artery (MCA) coming from a complicated carotid atheroma, non-stenosing in the first case (a 49 years old man) and stenosing in the second case (a 71 years old man) without clinical indications to intravenous thrombolysis and/or EVT, extensively investigated in the acute phase and followed-up for over 12 months with a favorable clinical course and the persisting steno-occlusion in the involved MCA. In both cases, antiplatelet treatment and targeting of vascular risk factors were done without recurrences in the follow-up period. DISCUSSION: Cerebral calcified embolism has been reported in 5.9% of cases of acute ischemic stroke in a single center series and only in 1.2% of a large retrospective cohort of EVT-treated patients. In both series the prognosis was poor and only one third of EVT-treated patients had functional independence at 3-months follow-up. The natural history of these subtype of ischemic stroke is relatively poorly understood and both etiological diagnosis and treatment have not yet defined. It is possible that some cases might be underdiagnosed and underreported. CONCLUSIONS: Calcified cerebral embolism is a rare cause of stroke, but it is largely underreported and both acute phase and secondary preventive treatment have to be defined.

Stroke-Induced Secondary Neurodegeneration of the Corticospinal Tract-Time Course and Mechanisms Underlying Signal Changes in Conventional and Advanced Magnetic Resonance Imaging.

Secondary neurodegeneration refers to the final result of several simultaneous and sequential mechanisms leading to the loss of substance and function in brain regions connected to the site of a primary injury. Stroke is one of the most frequent primary injuries. Among the subtypes of post-stroke secondary neurodegeneration, axonal degeneration of the corticospinal tract, also known as Wallerian degeneration, is the most known, and it directly impacts motor functions, which is crucial for the motor outcome. The timing of its appearance in imaging studies is usually considered late (over 4 weeks), but some diffusion-based magnetic resonance imaging (MRI) techniques, as diffusion tensor imaging (DTI), might show alterations as early as within 7 days from the stroke. The different sequential pathological stages of secondary neurodegeneration provide an interpretation of the signal changes seen by MRI in accordance with the underlying mechanisms of axonal necrosis and repair. Depending on the employed MRI technique and on the timing of imaging, different rates and thresholds of Wallerian degeneration have been provided in the literature. In fact, three main pathological stages of Wallerian degeneration are recognizable-acute, subacute and chronic-and MRI might show different changes: respectively, hyperintensity on T2-weighted sequences with corresponding diffusion restriction (14-20 days after the injury), followed by transient hypointensity of the tract on T2-weighted sequences, and by hyperintensity and atrophy of the tract on T2-weighted sequences. This is the main reason why this review is focused on MRI signal changes underlying Wallerian degeneration. The identification of secondary neurodegeneration, and in particular Wallerian degeneration, has been proposed as a prognostic indicator for motor outcome after stroke. In this review, the main mechanisms and neuroimaging features of Wallerian degeneration in adults are addressed, focusing on the time and mechanisms of tissue damage underlying the signal changes in MRI.

Tumor-like Lesions in Primary Angiitis of the Central Nervous System: The Role of Magnetic Resonance Imaging in Differential Diagnosis.

Primary Angiitis of the Central Nervous System (PACNS) is a rare disease and its diagnosis is a challenge for several reasons, including the lack of specificity of the main findings highlighted in the current diagnostic criteria. Among the neuroimaging pattern of PACNS, a tumefactive form (t-PACNS) is a rare subtype and its differential diagnosis mainly relies on neuroimaging. Tumor-like mass lesions in the brain are a heterogeneous category including tumors (in particular, primary brain tumors such as glial tumors and lymphoma), inflammatory (e.g., t-PACNS, tumefactive demyelinating lesions, and neurosarcoidosis), and infectious diseases (e.g., neurotoxoplasmosis). In this review, the main features of t-PACNS are addressed and the main differential diagnoses from a neuroimaging perspective (mainly Magnetic Resonance Imaging-MRI-techniques) are described, including conventional and advanced MRI.

The Prepetrous Segment of the Internal Carotid Artery as a Neglected Site of Symptomatic Atherosclerosis: A Single-Center Series.

(1) Background: Non-stenotic complicated plaques are a neglected cause of stroke, in particular in young patients. Atherosclerosis has some preferential sites in extracranial arteries and the prepetrous segment of the internal carotid artery has been rarely described as site of atheroma in general and of complicated atheroma in stroke patients. The aim of this study is to describe the rate of the prepetrous internal carotid artery's (ICA) involvement in a single-center case series of young stroke patients. (2) Methods: All patients < 50 years old with acute ischemic stroke admitted to a single-center Stroke Unit during two time periods (the first one from 1 January 2018 to 31 December 2019, and the second one from 1 January 2021 to 30 June 2022), were prospectively investigated as part of a screening protocol of the Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO) study [ClinicalTrials.gov ID NCT01934725], including extracranial vascular examination by using computed tomography (CT) or magnetic resonance imaging (MRI). (3) Results: Two out of ninety-three consecutive patients (2.15%) had a complicated atheroma in the prepetrous ICA as the cause of stroke and both CT angiography and high-resolution vessel wall MRI were applied to document the main features of positive remodeling, cap rupture, ulceration, intraplaque hemorrhage, and a transient thrombus superimposed on the atheroma. The two patients had a different evolution of healing in the first case and a persisting ulceration at 12 months in the second case. (4) Conclusions: The prepetrous ICA is a rarely described location of complicated atheroma in stroke patients at all ages and it represents roughly 2% of causes of acute stroke in this single-center case series in young people.

Prediction of diabetes insipidus occurrence after endoscopic endonasal removal of sellar lesions using MRI-based radiomics and machine learning.

BACKGROUND: Pituitary adenomas and craniopharyngiomas are the most common lesions of the sellar region. These tumors are responsible for invasion or compression of crucial neurovascular structures. The involvement of the pituitary stalk warrants high rates of both pre- and post- operative diabetes insipidus. The aim of our study was to assess the accuracy of machine learning analysis from preoperative MRI of pituitary adenomas and craniopharyngiomas for the prediction of DI occurrence. METHODS: All patients underwent MRI exams either on a 1.5- or 3-T MR scanner from two Institutions, including coronal T2-weighted (T2-w) and contrast-enhanced T1-weighted (CE T1-w) Turbo Spin Echo sequences. Feature selection was carried out as a multi-step process, with a threshold of 0.75 to identify robust features. Further feature selection steps included filtering based on feature variance (threshold >0.01) and pairwise correlation (threshold <0.80). A Bayesian Network model was trained with 10-fold cross validation employing SMOTE to balance classes exclusively within the training folds. RESULTS: Thirty patients were included in this study. In total 2394 features were extracted and 1791 (75%) resulted stable after ICC analysis. The number of variant features was 1351 and of non-colinear features was 125. Finally, 10 features were selected by oneR ranking. The Bayesian Network model showed an accuracy of 63% with a precision of 77% for DI prediction (0.68 area under the precision-recall curve). CONCLUSIONS: We assessed the accuracy of machine learning analysis of texture-derived parameters from preoperative MRI of pituitary adenomas and craniopharyngiomas for the prediction of DI occurrence.

The impact of radiomics for human papillomavirus status prediction in oropharyngeal cancer: systematic review and radiomics quality score assessment.

PURPOSE: Human papillomavirus (HPV) status assessment is crucial for decision making in oropharyngeal cancer patients. In last years, several articles have been published investigating the possible role of radiomics in distinguishing HPV-positive from HPV-negative neoplasms. Aim of this review was to perform a systematic quality assessment of radiomic studies published on this topic. METHODS: Radiomics studies on HPV status prediction in oropharyngeal cancer patients were selected. The Radiomic Quality Score (RQS) was assessed by three readers to evaluate their methodological quality. In addition, possible correlations between RQS% and journal type, year of publication, impact factor, and journal rank were investigated. RESULTS: After the literature search, 19 articles were selected whose RQS median was 33% (range 0-42%). Overall, 16/19 studies included a well-documented imaging protocol, 13/19 demonstrated phenotypic differences, and all were compared with the current gold standard. No study included a public protocol, phantom study, or imaging at multiple time points. More than half (13/19) included feature selection and only 2 were comprehensive of non-radiomic features. Mean RQS was significantly higher in clinical journals. CONCLUSION: Radiomics has been proposed for oropharyngeal cancer HPV status assessment, with promising results. However, these are supported by low methodological quality investigations. Further studies with higher methodological quality, appropriate standardization, and greater attention to validation are necessary prior to clinical adoption.