Point-Of-Care low-field MRI in acute Stroke (POCS): protocol for a multicentric prospective open-label study evaluating diagnostic accuracy.

INTRODUCTION: Fast and accurate diagnosis of acute stroke is crucial to timely initiate reperfusion therapies. Conventional high-field (HF) MRI yields the highest accuracy in discriminating early ischaemia from haemorrhages and mimics. Rapid access to HF-MRI is often limited by contraindications or unavailability. Low-field (LF) MRI (<0.5T) can detect several types of brain injury, including ischaemic and haemorrhagic stroke. Implementing LF-MRI in acute stroke care may offer several advantages, including extended applicability, increased safety, faster administration, reduced staffing and costs. This multicentric prospective open-label trial aims to evaluate the diagnostic accuracy of LF-MRI, as a tool to guide treatment decision in acute stroke. METHODS AND ANALYSIS: Consecutive patients accessing the emergency department with suspected stroke dispatch will be recruited at three Italian study units: Azienda Sanitaria Locale (ASL) Abruzzo 1 and 2, Istituto di Ricerca e Cura a Carattere Scientifico (IRCCS) Humanitas Research Hospital. The estimated sample size is 300 patients. Anonymised clinical and LF-MRI data, along with conventional neuroimaging data, will be independently assessed by two external units: Marche Polytechnic University and 'G. Martino' Polyclinic University Hospital. Both units will independently adjudicate the best treatment option, while the latter will provide historical HF-MRI data to develop artificial intelligence algorithms for LF-MRI images interpretation (Free University of Bozen-Bolzano). Agreement with conventional neuroimaging will be evaluated at different time points: hyperacute, acute (24 hours), subacute (72 hours), at discharge and chronic (4 weeks). Further investigations will include feasibility study to develop a mobile stroke unit equipped with LF-MRI and cost-effectiveness analysis. This trial will provide necessary data to validate the use of LF-MRI in acute stroke care. ETHICS AND DISSEMINATION: The study was approved by the Research Ethics Committee of the Abruzzo Region (CEtRA) on 11 May 2023 (approval code: richyvgrg). Results will be disseminated in peer-reviewed journals and presented in academic conferences. TRIAL REGISTRATION NUMBER: NCT05816213; Pre-Results.

Factors associated with hemorrhagic transformation after endovascular treatment despite early recanalization.

PURPOSE: To identify new factors associated with hemorrhagic transformation (HT) despite early recanalization in patients with acute ischemic stroke treated with mechanical thrombectomy. METHODS: We retrospectively included patients with known onset of large vessel occlusion treated with mechanical thrombectomy +/- intravenous thrombolysis. Non-contrast CT was performed at 24 +/- 12 h from endovascular procedure. We collected data on patient characteristics, risk factors, radiological and treatment features, stroke severity on admission and discharge, carotid intima-media thickness (CIMT), Neutrophils-to-Lymphocytes ratio (NLR), white matter hyperintensities measured according to the Fazekas score on FLAIR MRI data. The main outcome measures were the incidence of HT and factors associated with it. Secondary outcome measures were symptomatic intracerebral hemorrhage and parenchymal hematoma. RESULTS: Of 874 patients, 472 met the inclusion criteria, 211 (44.7%) had HT. Factors significantly associated with increased risk of HT included onset-to-recanalization time, CIMT (normal/mild), ASPECT-MRI < 6, and a higher NLR. We found that beyond 7.67 h from onset-to-recanalization, the risk of HT increases and exceeds 50%. ASPECT-MRI, NLR, and CIMT independently predict HT despite early recanalization. CONCLUSIONS: We identified novel factors associated with HT in patients with acute ischemic stroke of known onset treated with mechanical thrombectomy. We found that at 7.67 h from onset to recanalization, the risk of HT is >50%, and we identified factors responsible for HT despite early recanalization.

Mechanical thrombectomy in young patients with large vessel occlusion-related ischemic stroke: Data from the Italian Registry of Endovascular Treatment in Acute Stroke.

BACKGROUND AND PURPOSE: The weight of outcome predictors in acute ischemic stroke (AIS) patients older than 60 years is not necessarily mirrored in the younger population, posing the question of whether outcome determinants specific for the latter might vary. Very few data are available on predictors of outcome in young AIS patients receiving endovascular treatment (EVT). METHODS: We analyzed data for patients aged between 16 and 55 years from the Italian Registry of Endovascular Treatment in Acute Stroke. We divided our population into patients <45 years old and patients aged between 45 and 55 years. After testing the differences between groups in terms of 90-day modified Rankin Scale (mRS) 0-2, mortality, and symptomatic intracranial hemorrhage, we looked for predictors of poor outcome (mRS 3-6), death, and symptomatic intracerebral hemorrhage in the two groups. RESULTS: A total of 438 patients younger than 45 years and 817 aged 45-55 years were included; 284 (34.8%) patients aged 45-55 years and 112 (25.6%) patients younger than 45 years old showed poor 90-day functional outcome (p = 0.001). Predictors of poor outcome in the older group were baseline National Institutes of Health Stroke Scale (NIHSS; p < 0.001), diabetes (p = 0.027), poor collateral status (p = 0.036), and groin puncture-to-recanalization time (p = 0.010), whereas Thrombolysis in Cerebral Infarction (TICI) 2b-3 had an inverse association (p < 0.001). Predictors of poor outcome in patients younger than 45 years were baseline NIHSS (p < 0.001) and groin puncture-to-recanalization time (p = 0.015), whereas an inverse association was found for baseline Alberta Stroke Program Early CT Score (p = 0.010) and TICI 2b-3 (p < 0.001). CONCLUSIONS: Approximately one third of young adults treated with EVT do not reach a good functional outcome. Fast and successful recanalization, rather than common risk factors, has a major role in determining clinical outcome.

Predictors for hemorrhagic transformation and cerebral edema in stroke patients with first-pass complete recanalization.

BACKGROUND: Predictors of radiological complications attributable to reperfusion injury remain unknown when baseline setting is optimal for endovascular treatment and procedural setting is the best in stroke patients with large vessel occlusion (LVO). AIMS: To identify clinical and radiological/procedural predictors for hemorrhagic transformation (HT) and cerebral edema (CED) at 24 hr in patients obtaining complete recanalization in one pass of thrombectomy for ischemic stroke ⩽ 6 h from symptom onset with intra-cranial anterior circulation LVO and ASPECTS ⩾ 6. METHODS: We conducted a cohort study on prospectively collected data from 1400 patients enrolled in the Italian Registry of Endovascular Treatment in Acute Stroke. RESULTS: HT was reported in 248 (18%) patients and early CED was reported in 260 (19.2%) patients. In the logistic regression model including predictors from a first model with clinical variables and from a second model with radiological/procedural variables, diabetes mellitus (odds ratio (OR) = 1.832, 95% confidence interval (CI) = 1.201-2.795), higher National Institutes of Health Stroke Scale (NIHSS) (OR = 1.076, 95% CI = 1.044-1.110), lower Alberta Stroke Program Early CT (ASPECTS) (OR = 0.815, 95% CI = 0.694-0.957), and longer onset-to-groin time (OR = 1.005, 95% CI = 1.002-1.007) were predictors of HT, whereas general anesthesia was inversely associated with HT (OR = 0.540, 95% CI = 0.355-0.820). Higher NIHSS (OR = 1.049, 95% CI = 1.021-1.077), lower ASPECTS (OR = 0.700, 95% CI = 0.613-0.801), intravenous thrombolysis (OR = 1.464, 95% CI = 1.061-2.020), longer onset-to-groin time (OR = 1.002, 95% CI = 1.001-1.005), and longer procedure time (OR = 1.009, 95% CI = 1.004-1.015) were predictors of early CED. After repeating a fourth logistic regression model including also good collaterals, the same variables remained predictors for HT and/or early CED, except diabetes mellitus and thrombolysis, while good collaterals were inversely associated with early CED (OR = 0.385, 95% CI = 0.248-0.599). CONCLUSIONS: Higher NIHSS, lower ASPECTS, and longer onset-to-groin time were predictors for both HT and early CED. General anesthesia and good collaterals were inversely associated with HT and early CED, respectively. Longer procedure time was predictor of early CED.

Mechanical thrombectomy in patients with heart failure: the Italian registry of Endovascular Treatment in Acute Stroke.

BACKGROUND: Heart failure (HF) is the second most important cardiac risk factor for stroke after atrial fibrillation (AF). Few data are available on mechanical thrombectomy (MT) in acute ischemic stroke (AIS) patients with HF. METHODS: The source of data is the multicentre Italian Registry of Endovascular Treatment in Acute Stroke (IRETAS). All AIS patients ≥ 18 years receiving MT were categorised in two groups: HF and no-HF. Baseline clinical and neuroradiological findings on admission were analysed. RESULTS: Of 8924 patients, 642 (7.2%) had HF. Compared to the no-HF group, HF patients had higher prevalence of cardiovascular risk factors. Rate of complete recanalisation (TICI 2b-3) was 76.9% in HF vs 78.1% in no-HF group (p = 0.481). Rate of symptomatic intracerebral haemorrhage at 24-h non-contrast computed tomography (NCCT) was 7.6% in HF vs 8.3% in no-HF patients (p = 0.520). At 3 months, 36.4% of HF patients and 48.2% of no-HF patients (p < 0.001) had mRS 0-2, and mortality was, respectively, 30.7% and 18.5% (p < 0.001). In multivariate logistic regression, HF was independently associated with mortality at 3 months (OR 1.53, 1.24-1.88 95% CI, p < 0.001). In multivariate ordinal regression, HF patients had a probability of transitioning to a higher mRS level of 1.23 (1.05-1.44 95% CI, p = 0.012). The propensity score analysis of two groups matched for age, sex, and NIHSS at admission yielded the same results. CONCLUSION: MT is safe and effective in HF patients with AIS. Patients with HF and AIS suffered from higher 3-month mortality and unfavourable outcome regardless of acute treatments.

Three-Dimensional Constructive Interference in Steady State (3D CISS) Imaging and Clinical Applications in Brain Pathology.

Three-dimensional constructive interference in steady state (3D CISS) is a steady-state gradient-echo sequence in magnetic resonance imaging (MRI) that has been used in an increasing number of applications in the study of brain disease in recent years. Owing to the very high spatial resolution, the strong hyperintensity of the cerebrospinal fluid signal and the high contrast-to-noise ratio, 3D CISS can be employed in a wide range of scenarios, ranging from the traditional study of cranial nerves, the ventricular system, the subarachnoid cisterns and related pathology to more recently discussed applications, such as the fundamental role it can assume in the setting of acute ischemic stroke, vascular malformations, infections and several brain tumors. In this review, after briefly summarizing its fundamental physical principles, we examine in detail the various applications of 3D CISS in brain imaging, providing numerous representative cases, so as to help radiologists improve its use in imaging protocols in daily clinical practice.

Magnetic Resonance Angiography and Cisternography fused images in acute ischemic stroke may save time during endovascular procedure revealing vessel anatomy.

Background and purpose: Endovascular treatment (EVT) is a time-dependent procedure that aims to remove the arterial blood flow obstruction in brain vessels in acute ischemic stroke. In our center, the MRI patient selection protocol in acute ischemic stroke is performed with DWI, FLAIR, MR angiography (MRA) and MR cisternography (MRC) sequences. MRA and MRC are promptly and automatically fused in order to have a clear detection of vessel anatomy, before and during EVT.Our study aim is to evaluate if the fusion process between MRA and MRC could be considered time-safe and could influence EVT duration or outcome. Materials and methods: 45 patients were retrospectively selected for the study and divided into 2 groups according to the presence of MRC sequence fused with MRA (Group 1) or not (Group 2 - controls). Results: MRA and MRC fusion was able to depict vessel anatomy in all subjects of Group 1 (22 patients, 12 females; age 75.59 years ± 10.87). Group 1 presented EVT time reduction (p < 0.05; p = 0.040) (51.59 min ± 30.94) when compared to Group 2 (23 patients, 13 females; age 75.04 years ± 12.12) (71.96 min ± 34.55) of 20.37 min average. No differences between groups were detected evaluating: NIHSS at admission (p = 0.49) and discharge (p = 0.67), pre-stroke mRS (p = 0.89), mRS at 90 days (p = 0.62), ASPECT (p = 0.98) and ASPECT-DWI scores (p = 0.93), time from symptom onset to groin puncture (p = 0.80), thromboaspiration vs combined technique (p = 0.67), EVT success (p = 0.63). Conclusion: Fusion of MRA and MRC is a safe and promising technique in promptly revealing vascular anatomy beyond vessel obstruction, and can play a role in EVT duration reduction.

Carotid free-floating thrombus during COVID-19 vaccine era: causality or not?

Carotid free-floating thrombus (FFT) is very rarely diagnosed in patients with acute ischemic stroke. It is a real clinical emergency due to the significant risk of death associated with thromboembolic complications. Herein, we present three patients with ischemic stroke caused by carotid FFT after less than 20 days from administration of mRNA vaccine BNT162b1 (Pfizer/BioNTech) for Severe Acute Respiratory Syndrome-CoronaVirus 2 (SARS-CoV-2). To our knowledge, these are the first cases reporting carotid FTT following SARS-CoV-2 vaccination.

Cisternostomy for malignant middle cerebral artery infarction: proposed pathophysiological mechanisms and preliminary results.

BACKGROUND: The ischaemic stroke of the territory of the middle cerebral artery represents an event burdened by high mortality and severe morbidity. The proposed medical treatments do not always prove effective. Decompressive craniectomy allows the ischaemic tissue to shift through the surgical defect rather than to the unaffected regions of the brain, thus avoiding secondary damage due to increased intracranial pressure. In this study, we propose a novel treatment for these patients characterised by surgical fenestration of the cisterns of the skull base. METHODS: We have treated 16 patients affected by malignant middle cerebral artery ischaemia and treated with cisternostomy between August 2018 and December 2019. The clinical history, neurological examination findings and neuroradiological studies (brain CT, CT angiography, MRI) were performed to diagnose stroke. Clinical examination was recorded on admission and preoperatively using the Glasgow Coma Scale and the National Institutes of Health Stroke Scale. RESULTS: The study included 16 patients, 10 males and 6 females. The mean age at surgery was 60.1 years (range 19-73). Surgical procedure was performed in all patients. The patients underwent immediate postoperative CT scan and were in the early hours evaluated in sedation window. In total, we recorded two deaths (12.5%). A functional outcome between mRS 0-3, defined as favourable, was observed in 9 (64.2%) patients 9 months after discharge. A functional outcome between mRS 4-6, defined as poor, was observed in 5 (35.7%) patients 9 months after discharge. CONCLUSIONS: The obtained clinical results appear, however, substantially overlapping to decompressive craniectomy. Cisternostomy results in a favourable functional outcome after 9 months. This proposed technique permits that the patient no longer should be undergone cranioplasty thus avoiding the possible complications related to this procedure. The results are certainly interesting but higher case numbers are needed to reach definitive conclusions.

Fusion of magnetic resonance angiography and cisternography in acute ischemic stroke reveals the vessel anatomy ahead of the clot: a technical note to see beyond obstacles.

We describe how the fusion process between magnetic resonance angiography (MRA) and cisternography (MRC) promptly reveals vessel anatomy ahead of the clot, in patients affected by acute anterior circulation large vessel occlusion. This technique showed in 100% of subjects (n = 22) a clear tracing of vessel anatomy before and beyond the clot. The duration of the whole process is short and could be considered safe since no outcome differences have been found when compared with a control group (n = 23). This technique could play a relevant role in guiding endovascular therapy, especially in unexpected unfavorable anatomical arteries configurations.

Moyamoya Vasculopathy: Cause, Clinical Manifestations, Neuroradiologic Features, and Surgical Management.

In moyamoya disease, the progressive occlusion of the distal portion of the internal carotid artery and its major branches is typically responsible for the formation of an extensive network of collateral vessels at the base of the brain. When moyamoya collateral network develops in association with various systemic or acquired diseases, the term moyamoya syndrome is used to denote this phenomenon. Sudden changes in the supraclinoid internal carotid artery and middle cerebral artery can be recognized with noninvasive neurovascular imaging techniques, which also allow a differential diagnosis with similar diseases such as degenerative steno-occlusive disease, cerebral vasculitis, and twig-like middle cerebral artery. Once the diagnosis is established, the definitive treatment for moyamoya disease is surgical revascularization, with the goal of increasing cerebral blood flow and preventing recurrent stroke. We provide a comprehensive review of the clinical and radiologic features in moyamoya vasculopathy along with its surgical management.

Ischemic stroke and reperfusion therapies in diabetic patients.

INTRODUCTION: The study aimed to identify the main prognostic factors in diabetic patients with ischemic stroke undergoing reperfusion therapies (RT). METHODS: This retrospective study included 170 diabetic patients: 62 treated with intravenous thrombolysis (IVT) alone and 108 with mechanical thrombectomy (MT). Among MT patients, 29 underwent IVT. We collected clinical, laboratory, and radiological data. The outcomes were 3-month functional impairment (measured by modified Rankin scale, mRs), discharge neurological severity (measured by National Institutes of Health Stroke Scale score, NIHSS), 3-month mortality, intracranial hemorrhage (ICH), and symptomatic intracranial hemorrhage (SICH). We performed a general analysis for all RT and sub-group analyses for IVT and MT. RESULTS: A lower mRs was associated with lower glycemia and admission NIHSS (aNIHSS) in all RT and MT; lower aNIHSS and younger age in IVT. Mortality increased with hyperglycemia, aNIHSS, and age in all RT; age and aNIHSS in IVT; hyperglycemia and systolic pressure in MT. A lower discharge NIHSS was related with lower aNIHSS, thrombolysis, and no thrombectomy in all RT; lower aNIHSS in IVT; lower aNIHSS and thrombolysis in MT. ICH was associated with elevated aNIHSS, older age, and lower platelets in all RT; lower platelets and older age in IVT; higher aNIHSS in MT. SICH depended on longer thrombectomy duration in all RT; no metformin use in IVT; higher weight in MT. CONCLUSION: The study shed light on diabetic patients and stroke RT highlighting the protective effect of metformin in IVT and the role of glycemia, weight, and combined treatment in MT.

Repeated reperfusion treatment in recurrent ischemic stroke: A retrospective single-center case series.

Data regarding repeated reperfusion therapy (rRT) in acute ischemic stroke (AIS), including intravenous thrombolysis and endovascular treatment (EVT), are quite poor. To date, there are only few case reports and five larger studies on repeated EVT. We aimed to report our single-center experience and describe different clinical scenarios of recurrent AIS with emergent large vessel occlusion (LVO), for which the decision-making process could be challenging in the emergency setting. We retrospectively reviewed 765 consecutive AIS patients with LVO, who underwent reperfusion procedures at our comprehensive stroke center, from 2014 to 2020, and identified rRT patients. We identified and reviewed the medical records of eight patients (1.05%), who repeated reperfusive treatment for recurrent stroke within 30 days (early arterial reocclusion, EAR) and after 30 days (late arterial reocclusion, LAR). We assigned collected data to three clinical scenarios, each divided into EAR and LAR cases. All patients had recurrent emergent LVO in the same vessel territory previously affected, both in EAR and LAR patients. A good clinical outcome has been achieved in EAR patients (modified Rankin Score ≤ 2). Artery-to-artery embolic mechanism was more common in the EAR group, while LAR was more frequently associated with cardioembolic source. RRT appears to be an effective treatment option for recurrent LVO, and it should not be withheld in carefully selected patients. EVT should be considered, including aspiration-only and stenting procedures in patients with AIS and recurrent LVO after previous reperfusive treatments, even after a very short time.

Microvascular imaging ultrasound (MicroV) and power Doppler vascularization analysis in a pediatric population with early scrotal pain onset.

INTRODUCTION: The power Doppler is a useful tool in the evaluation of pediatric acute scrotal pain. Nonetheless, it may have some inherent limitations in scrotal vascularization analysis, potentially causing unnecessary surgery. The microvascular imaging ultrasound (MicroV) is an innovative Doppler technique able to improve the detection of very low flow. This retrospective study aims to compare both power Doppler and MicroV in the evaluation of a pediatric population with early-stage scrotal pain onset, first in testis vascularization analysis, and second in their diagnostic performances. MATERIALS AND METHODS: 69 patients met the following inclusion criteria, age < 18-year-old, a clinical diagnosis of acute scrotal disease, pain onset ≤ 6 h, ultrasound examination (including B-mode, power Doppler, and MicroV), 3-months follow-up. For both power Doppler and MicroV, through a defined vascularization scale, it was evaluated the agreement in vascularization detection, and the sensitivity and specificity in US diagnostic abilities. RESULTS: Retrospective diagnoses were of 8 testicular torsion, 15 orchi-epididymitis, and 46 children with other scrotal conditions. Power Doppler provided inconclusive US evaluation in 37.68% of the cases, while MicroV only in the 1.45% (p < 0.0001). Testicular torsion and orchi-epididymitis were identified, respectively, with MicroV in 100% (sensitivity, specificity, PPV, NPV, and accuracy of 100%) and 80% of patients (80% sensitivity, 100% specificity and PPV, 94.73% NPV, 95.65% accuracy); with power Doppler the identification was, respectively, of 87.5% (87.5% sensitivity, 100% specificity and PPV, 98.38% NPV and accuracy) and of 73.3% (73.33% sensitivity, 98.14% specificity, 91.66% PPV, 92.98% NPV, 92.75% accuracy). CONCLUSIONS: Our findings indicate that MicroV is a reliable technique in vascularization detection of pediatric testes, being able also to detect vascularization in healthy testicles with no-flow at power Doppler examination. Moreover, MicroV could be a valuable ally in the US diagnostic of children with early-stage scrotal pain onset.

Comparison of aspiration versus combined technique as first-line approach in terminal internal carotid artery occlusion: a multicenter experience.

BACKGROUND: There is no consensus on the most effective endovascular technique to use in patients with acute ischemic stroke due to terminal internal carotid artery (ICA) occlusion. The aim of this study was to compare safety and efficacy of the aspiration technique (AT) and combined technique (CT) as first-line approach in terminal ICA occlusions. METHODS: We performed a retrospective analysis of prospectively collected databases from seven Italian stroke centers. Patients were divided into two subgroups according to the first-line approach: AT group or CT group. We followed the STROBE guidelines for cohort studies. We used Chi-square test, one-way and multivariate ANOVA analysis, together with contrast analysis and post hoc tests, logistic regression and Pearson's bivariate correlation for the statistical analyses. RESULTS: Between January 2018 and August 2020, 353 patients were treated for a terminal ICA occlusion, with either AT or CT. CT was associated with a higher Thrombolysis in Cerebral Infarction (TICI) 2B-3 after the first pass (51.0% vs 26.9%) and at the end of the procedure (84% vs 73.3%) and with an improved clinical outcome at discharge (modified Rankin Scale (mRs) 0-2 of 47.8% vs 34.0%) and at 3 months' follow-up (mRs 0-2 of 56.5% vs 38.9%) compared with AT. CONCLUSION: Thrombectomy of terminal ICA occlusions obtained using CT as first-line approach demonstrated better technical and functional outcomes in comparison with AT.

Mechanical thrombectomy in acute ischemic stroke due to large vessel occlusion in the anterior circulation and low baseline National Institute of Health Stroke Scale score: a multicenter retrospective matched analysis.

BACKGROUND AND PURPOSE: The benefit of mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO) and baseline mild neurological symptoms remains unclear. The purpose of this study was to evaluate the effectiveness of MT in this subgroup of patients. METHODS: The databases of 9 high-volume Italian stroke centers were retrospectively screened for patients with LVO in the anterior circulation and a baseline National Institute of Health Stroke Scale (NIHSS) score ≤ 5 that received either immediate MT or best medical management (BMM) with the possibility of rescue MT upon neurological worsening. Primary outcome measure was a modified Rankin Scale score of 0-1 at 90 days. Propensity score matching (PSM) analysis was used to estimate the treatment effect of immediate MT compared to BMM/rescue MT. RESULTS: Two hundred and seventy-two patients received immediate MT (MT group). The BMM/rescue MT group included 41 patients. The primary outcome was achieved in 78.6% (n = 246) of overall patients, with a higher proportion in the MT group (80.5% vs. 65.9%, p = 0.03) in unadjusted analysis. After PSM, patients in the MT group had a 19.5% higher chance of excellent outcome at 90 days compared to the BMM/Rescue MT group with a similar risk of death from any cause. CONCLUSIONS: Our experience is in favor of a potential benefit of MT also in patients with LVO and a NIHSS score ≤ 5 at the time of groin puncture. Nonetheless, this issue waits for a clear-cut recommendation in a dedicated clinical trial.

Magnetism of materials: theory and practice in magnetic resonance imaging.

All substances exert magnetic properties in some extent when placed in an external magnetic field. Magnetic susceptibility represents a measure of the magnitude of magnetization of a certain substance when the external magnetic field is applied. Depending on the tendency to be repelled or attracted by the magnetic field and in the latter case on the magnitude of this effect, materials can be classified as diamagnetic or paramagnetic, superparamagnetic and ferromagnetic, respectively. Knowledge of type and extent of susceptibility of common endogenous and exogenous substances and how their magnetic properties affect the conventional sequences used in magnetic resonance imaging (MRI) can help recognize them and exalt or minimize their presence in the acquired images, so as to improve diagnosis in a wide variety of benign and malignant diseases. Furthermore, in the context of diamagnetic susceptibility, chemical shift imaging enables to assess the intra-voxel ratio between water and fat content, analyzing the tissue composition of various organs and allowing a precise fat quantification. The following article reviews the fundamental physical principles of magnetic susceptibility and examines the magnetic properties of the principal endogenous and exogenous substances of interest in MRI, providing potential through representative cases for improved diagnosis in daily clinical routine.

Safety and effect of Neuroform Atlas stent in the treatment of symptomatic intracranial stenosis: A single-center experience.

BACKGROUND: Vascular intracranial stenosis (IS) is a significant cause of acute ischemic stroke (AIS). This single-center study aims to show that symptomatic IS treatment by using the Neuroform Atlas stent (Stryker neurovascular, Kalamazoo, MI, USA) could be effective in reducing vessel stenosis. METHODS: Ten patients affected by AIS or TIA, in the vascular territory of high-grade intracranial atherosclerotic lesions (>70% of vessel stenosis), older than 18-year-old, were treated by implanting a Neuroform Atlas stent (diameter of 4.5mm in 80% and 4mm in 20%). 70% of the patients underwent pre-stenting intracranial angioplasty. RESULTS: Patients were between 54.8 and 83 years old (mean 68.46y ± 8.44y), 70% males and 30% females. At admission, 50% of all patients had an AIS and 50% a TIA. Restoration of the stenotic lumen was obtained after the endovascular procedure. The percentage mean of vascular stenosis was 83.7% ± 6.09% before treatment (t0), 52.2% ± 10.42% at the end of treatment (t1) and 46.2% ± 8.28% at the follow-up (t2). The IS percentage mean reduction between t0 and t1 was 31.5% ± 7.31%, and between t1 and t2 was 6% ± 5.47%, t0 and t2 of 37.5% ± 7.38%. Percentage reduction of IS was highly significant between time t0 and t1 (p = 0.005), and t0 and t2 (p = 0.005), also with a significant reduction between t1 and t2 (p = 0.012). No patient had experienced an increase of the ischemic area in the vascular territory of the target vessel at 3 months from the initial assessment. 10% of patients experienced a 3-months negative outcome (mRS = 5), 90% experienced a favorable outcome (mRS ≤2). CONCLUSIONS: Intracranial stenosis endovascular treatment with Neuroform Atlas stent provides encouraging results, with a statistically significant association between the vascular caliber improvement and the endovascular treatment.

Cerebellar amelanotic melanoma can mimic cerebellar abscess in a pediatric case of neurocutaneous melanosis.

Neurocutaneous melanosis (NCM) is a rare phakomatosis that may be associated with intracerebral masses. The differential diagnosis of intracerebral masses in NCM is often challenging and should include pigmented and nonpigmented lesions.

Imaging and Clinical Features of Neurocutaneous Melanosis in the Pediatric Population.

BACKGROUND: Neurocutaneous Melanosis (NCM) is a rare nonfamilial phakomatosis characterized by the presence of congenital melanocytic nevi and abnormal melanocyte infiltration of the leptomeninges. OBJECTIVE AND METHODS: This paper shows the importance of early diagnosis and the most important imaging features of the disease on CT and MR scans. PubMed database was searched from January 1972 to September 2020. Papers including imaging findings of NCM, clinical, follow-up, and treatment features were collected, selecting only 89 studies. DISCUSSION: NCM is a term used for the first time by van Bogaert in 1948. It refers to a condition caused by an error during morphogenesis and migration leading to leptomeningeal melanocytic accumulation. Although histological findings are the gold standard for diagnosis confirmation, neuroimaging and clinical features strongly support the suspect of NCM. Localization and extension of the lesions are predictive of neurological manifestations related to increased intracranial pressure, mass lesions, or spinal cord compression. CT demonstrates sites of increased density in the anterior temporal lobe, mainly the amygdala, thalami, cerebellum, and frontal lobes base. However, MRI is the best imaging method to diagnose central nervous system lesions, often appearing as T1-short signal areas of the cerebral parenchyma, indicative of central nervous system melanosis. MRI can also reveal associated intracranial and intraspinal abnormalities. CONCLUSION: Early imaging, when available, is helpful if NCM suspect is raised and may be of guidance in comparing later studies. NCM requires a multidisciplinary approach since it is a multisystem disease with a genetic component.