Valentina Lolli

PURPOSE: Posterior fossa ring-enhancing lesions (PFREL) in the adult immunocompetent hosts pose a diagnostic challenge. We aimed to evaluate the spectrum of PFREL etiologies and propose a diagnostic algorithm. METHODS: This study involved a retrospective analysis of PFREL cases from our institution (January 2023 to April 2024) and a systematic literature review conducted using Embase and PubMed databases following the PRISMA 2020 guidelines. Clinical and radiological features from these cases formed the basis of a diagnostic algorithm, which was further refined via an additional comprehensive literature review, and finally validated on an independent set of PFREL cases. RESULTS: The systematic review (467 studies, 56 selected after inclusion/exclusion criteria) revealed that PFREL etiology was infectious in 52%, tumoral in 38% and inflammatory in 2% of cases. At initial presentation, mean age was 48 years and 36% of patients had multiple PFREL. Headache was the most common symptom (46%). Among those with reported outcomes, 36% showed complete resolution of symptoms, 29% showed improvement with residual symptoms, and 16% died. The diagnostic algorithm was created from a total of 116 PFREL cases (10 from our institutional series, 56 from the systematic literature review and 50 supplementary cases found in the literature) and included 29 possible PFREL etiologies. In the validation set (16 patients), the algorithm provided the correct diagnosis in each case. CONCLUSION: PFREL in immunocompetent adults encompass a broad differential diagnosis. Our algorithm integrates clinical and radiologic data to assist in identifying the underlying cause of PFREL, potentially reducing the need for neurosurgical biopsy. This approach aims to enhance diagnostic accuracy, leading to better treatment decisions and improved patient outcomes. ABBREVIATIONS: ADEM = acute disseminated encephalomyelitis; CLL = chronic lymphocytic leukemia; CSF = cerebrospinal fluid; DLBCL: diffuse large B cell lymphoma; FLAIR = fluid attenuated inversion recovery; MeSH = medical subject headings; MRI = magnetic resonance imaging; NIHSS = National Institutes of Health Stroke Scale; NMOSD = neuromyelitis optic spectrum disorder; PFREL = posterior fossa ring enhancing lesion; PRISMA = Preferred Reporting Items for Systematic reviews and Meta-Analyses; SUV max = maximum standardized uptake value.

CT perfusion (CTP) images can be easily and rapidly obtained on all modern CT scanners and have become part of the routine imaging protocol of patients with aneurysmal subarachnoid haemorrhage (aSAH). There is a growing body of evidence supporting the use of CTP imaging in these patients, however, there are significant differences in the software packages and methods of analysing CTP. In. addition, no quantitative threshold values for tissue at risk (TAR) have been validated in this patients’ population. Here we discuss the contribution of the technique in the identification of patients at risk of aSAH-related delayed cerebral ischemia (DCI) and in the assessment of the response to endovascular rescue therapy (ERT). We also address the limitations and pitfalls of automated CTP postprocessing that are specific to aSAH patients as compared to acute ischemic stroke (AIS).

Purpose Task-based BOLD fMRI and DTI-fiber tracking have become part of the routine presurgical work-up of brain tumor patients in many institutions. However, their potential impact on both surgical treatment and neurologic outcome remains unclear, in despite of the high costs and complex implementation. Methods We retrospectively investigated whether performing fMRI and DTI-ft preoperatively substantially impacted surgical planning and patient outcome in a series of brain tumor patients. We assessed (i) the quality of fMRI and DTI-ft results, by using a scale of 0–2 (0 = failed mapping; 1 = intermediate confidence; 2 = good confidence), (ii) whether functional planning substantially contributed to defining the surgical strategy to be undertaken (i.e., no surgery, biopsy, or resection, with or without ESM), the surgical entry point and extent of resection, and (iii) the incidence of neurological deficits post-operatively. Results Twenty-seven patients constituted the study population. The mean confidence rating was 1.9/2 for fMRI localization of the eloquent cortex and lateralization of the language function and 1.7/2 for DTI-ft results. Treatment strategy was altered in 33% (9/27) of cases. Surgical entry point was modified in 8% (2/25) of cases. The extent of resection was modified in 40% (10/25). One patient (1/25, 4%) developed one new functional deficit post-operatively. Conclusion Functional MR mapping — which must not be considered an alternative to ESM — has a critical role preoperatively, potentially modifying treatment strategy or increasing the neurosurgeons’ confidence in the surgical approach hypothesized based on conventional imaging.

Brain metastasis (BM) is a frequent complication of systemic cancer usually associated with poor prognosis. Survival depends on numerous factors, which complicates prognosis and treatment. It has been suggested that BM growing from previously dormant disseminated tumour cells (DTCs) may exhibit a milder phenotype than BM derived from continuously progressing metastatic cells; however, to the best of our knowledge, the prognosis of patients presenting with BM from dormant DTCs is unknown. The present study retrospectively compared survival data, collected from a single neurosurgical centre, between patients presenting with BM from previously dormant DTCs and patients with non‑dormant BM. A total of 262 medical records were reviewed. In the univariate Cox regression analysis, the median survival of the dormant BM group was statistically longer than that of the non‑dormant group (P=0.048); a trend towards a longer survival persisted after correcting for age, presence of breast cancer and treatment options (P=0.057), which are all factors known to influence outcome. The improved outcome of these patients could be considered in models for prognostication. Moreover, the development of therapies able to eradicate dormant DTCs could provide a new promising strategy to prolong the survival of patients with a favourable prognosis.

Post-operative intracranial bleeding at a distance from the surgical site is a rare complication of both cranial and spinal surgeries and is referred to as remote intracranial hemorrhage (RIH). Bleeding typically occurs in the cerebellum. Simultaneous hemorrhages in different cranial compartments have been rarely observed. We herein report two cases of RIH, which showed different imaging patterns and clinical signs and symptoms. RIH are typically self-limiting and do not usually require treatment. Physicians must be aware of this benign entity which needs not be misdiagnosed with other conditions.

Background: The central vein sign (CVS) is an imaging biomarker able to differentiate multiple sclerosis (MS) from other conditions causing similar appearance lesions on magnetic resonance imaging (MRI), including cerebral small vessel disease (CSVD). However, the impact of vascular risk factors (VRFs) for CSVD on the percentage of CVS positive (CVS⁺) lesions in MS has never been evaluated. Objective: To investigate the association between different VRFs and the percentage of CVS⁺ lesions in MS. Methods: In 50 MS patients, 3T brain MRIs (including high-resolution 3-dimensional T2*-weighted images) were analyzed for the presence of the CVS and MRI markers of CSVD. A backward stepwise regression model was used to predict the combined predictive effect of VRF (i.e. age, hypertension, diabetes, obesity, ever-smoking, and hypercholesterolemia) and MRI markers of CSVD on the CVS. Results: The median frequency of CVS⁺ lesions was 71% (range: 35%–100%). In univariate analysis, age ( p < 0.0001), hypertension ( p < 0.001), diabetes ( p < 0.01), obesity ( p < 0.01), smoking ( p < 0.05), and the presence of enlarged-perivascular-spaces on MRI ( p < 0.005) were all associated with a lower percentage of CVS⁺ lesions. The stepwise regression model showed that age and arterial hypertension were both associated with the percentage of CVS⁺ lesions in MS (adjusted R² = 0.46; p < 0.0001 and p = 0.01, respectively). Conclusion: The proportion of CVS⁺ lesions significantly decreases in older and hypertensive MS patients. Although this study was conducted in patients with an already established MS diagnosis, the diagnostic yield of the previously proposed 35% CVS proportion-based diagnostic threshold appears to be not affected. Overall these results suggest that the presence of VRF for CSVD should be taken into account during the CVS assessment.

Acute hyperammonemic encephalopathy is a rare but life-threatening condition that might complicate liver disease as well as non-hepatic conditions. It can lead to coma and death, secondary to brain edema and intracranial hypertension. We present three cases of acute hyperammonemic encephalopathy of different etiologies and the observed brain MRI findings. Symmetrical extensive cortical signal abnormalities, typically involving the insular and cingulate cortices, often showing restricted diffusion, are commonly described. These specific imaging features should be recognized by the radiologist since prompt treatment of the condition is paramount.