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OBJECTIVES: To compare dual-energy CT (DECT) and MRI for assessing presence and extent of traumatic bone marrow edema (BME) and fracture line depiction in acute vertebral fractures. METHODS: Eighty-eight consecutive patients who underwent dual-source DECT and 3-T MRI of the spine were retrospectively analyzed. Five radiologists assessed all vertebrae for presence and extent of BME and for identification of acute fracture lines on MRI and, after 12 weeks, on DECT series. Additionally, image quality, image noise, and diagnostic confidence for overall diagnosis of acute vertebral fracture were assessed. Quantitative analysis of CT numbers was performed by a sixth radiologist. Two radiologists analyzed MRI and grayscale DECT series to define the reference standard. RESULTS: For assessing BME presence and extent, DECT showed high sensitivity (89% and 84%, respectively) and specificity (98% in both), and similarly high diagnostic confidence compared to MRI (2.30 vs. 2.32; range 0-3) for the detection of BME (p = .72). For evaluating acute fracture lines, MRI achieved high specificity (95%), moderate sensitivity (76%), and a significantly lower diagnostic confidence compared to DECT (2.42 vs. 2.62, range 0-3) (p < .001). A cutoff value of - 0.43 HU provided a sensitivity of 89% and a specificity of 90% for diagnosing BME, with an overall AUC of 0.96. CONCLUSIONS: DECT and MRI provide high diagnostic confidence and image quality for assessing acute vertebral fractures. While DECT achieved high overall diagnostic accuracy in the analysis of BME presence and extent, MRI provided moderate sensitivity and lower confidence for evaluating fracture lines. KEY POINTS: ⢠In the setting of spinal trauma, dual-energy CT (DECT) is highly accurate in the evaluation of acute vertebral fractures and bone marrow edema presence and extent. ⢠MRI provides moderate sensitivity and lower diagnostic confidence for the depiction of acute fracture lines, when compared to DECT, which might result in potentially inaccurate and underestimated severity assessment of injuries in certain cases when no fracture lines are visible on MRI. ⢠DECT may represent a valid imaging alternative to MRI in specific settings of acute spinal trauma and in follow-up examinations, especially in elderly or unstable patients and in cases of subtle or complex orientated fracture lines.
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Fracturas de la Columna Vertebral , Anciano , Médula Ósea , Edema/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Estudios Retrospectivos , Sensibilidad y Especificidad , Fracturas de la Columna Vertebral/diagnóstico por imagen , Tomografía Computarizada por Rayos XRESUMEN
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.
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Isquemia Encefálica , Procedimientos Endovasculares , Accidente Cerebrovascular Isquémico , Accidente Cerebrovascular , Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/terapia , Humanos , Angiografía por Resonancia Magnética/métodos , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/terapiaRESUMEN
Pompe disease is a rare hereditary metabolic disorder caused by α-glucosidase (GAA) deficiency. The late-onset form of the disease (LOPD) is considered a multisystemic disorder which could involve vascular system with cerebrovascular abnormalities such as intracranial aneurysms or dolichoectasia. Intracranial aneurysm rupture may represent a life-threatening emergency. A possible treatment of unruptured intracranial aneurysms (UIAs) should consider both aneurysm-related (aneurysmal size, shape, localization, numbers and hemodynamic factors) and patient-related risk factors (patient's age and sex, hypertension, smoke exposure). Moreover, UIAs management of LOPD patients needs also to take into account the altered blood vessels integrity and elasticity, whose consistency is likely weakened by the deficient GAA activity as a further potential risk factor. We herein present our approach for of UIAs management in three patients with LOPD. Among them, only one patient with a left saccular UIA of the anterior communicating artery, after careful consideration of risk factors, underwent the endovascular treatment. The other two patients were scheduled for a 1-year follow-up, according to radiological, clinical, and risk evaluation features. Finally, we would like to suggest some general recommendations for UIAs management. In particular, if no risk factors are identified, a cautious yearly follow-up is suggested; otherwise, if risk factors are present, endovascular treatment should be considered.
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Aneurisma Roto , Enfermedad del Almacenamiento de Glucógeno Tipo II , Aneurisma Intracraneal , Enfermedad del Almacenamiento de Glucógeno Tipo II/complicaciones , Enfermedad del Almacenamiento de Glucógeno Tipo II/terapia , Humanos , Aneurisma Intracraneal/complicaciones , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/terapia , Factores de Riesgo , alfa-GlucosidasasRESUMEN
BACKGROUND AND PURPOSE: To evaluate outcome and safety of endovascular treatment beyond 6 hours of onset of ischemic stroke due to large vessel occlusion in the anterior circulation, in routine clinical practice. METHODS: From the Italian Registry of Endovascular Thrombectomy, we extracted clinical and outcome data of patients treated for stroke of known onset beyond 6 hours. Additional inclusion criteria were prestroke modified Rankin Scale score ≤2 and ASPECTS score ≥6. Patients were selected on individual basis by a combination of CT perfusion mismatch (difference between total hypoperfusion and infarct core sizes) and CT collateral score. The primary outcome measure was the score on modified Rankin Scale at 90 days. Safety outcomes were 90-day mortality and the occurrence of symptomatic intracranial hemorrhage. Data were compared with those from patients treated within 6 hours. RESULTS: Out of 3057 patients, 327 were treated beyond 6 hours. Their mean age was 66.8±14.9 years, the median baseline National Institutes of Health Stroke Scale 16, and the median onset to groin puncture time 430 minutes. The most frequent site of occlusion was middle cerebral artery (45.1%). Functional independence (90-day modified Rankin Scale score, 0-2) was achieved by 41.3% of cases. Symptomatic intracranial hemorrhage occurred in 6.7% of patients, and 3-month case fatality rate was 17.1%. The probability of surviving with modified Rankin Scale score, 0-2 (odds ratio, 0.58 [95% CI, 0.43-0.77]) was significantly lower in patients treated beyond 6 hours as compared with patients treated earlier No differences were found regarding recanalization rates and safety outcomes between patients treated within and beyond 6 hours. There were no differences in outcome between people treated 6-12 hours from onset (278 patients) and those treated 12 to 24 hours from onset (49 patients). CONCLUSIONS: This real-world study suggests that in patients with large vessel occlusion selected on the basis of CT perfusion and collateral circulation assessment, endovascular treatment beyond 6 hours is feasible and safe with no increase in symptomatic intracranial hemorrhage.
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Isquemia Encefálica/cirugía , Hemorragias Intracraneales/cirugía , Accidente Cerebrovascular/cirugía , Trombectomía , Anciano , Angiografía Cerebral/métodos , Procedimientos Endovasculares/métodos , Femenino , Humanos , Isquemia/cirugía , Masculino , Persona de Mediana Edad , Arteria Cerebral Media/fisiopatología , Arteria Cerebral Media/cirugía , Trombectomía/métodos , Factores de TiempoRESUMEN
Brain arteriovenous malformation (bAVM) is a congenital defect affecting brain microvasculature, characterized by a direct shunt from arterioles to venules. Germline mutations in several genes related to transforming growth factor beta (TGF-ß)/BMP signaling are linked to both sporadic and hereditary phenotypes. However, the low incidence of inherited cases makes the genetic bases of the disease unclear. To increase this knowledge, we performed a whole exome sequencing on five patients, on DNA purified by peripheral blood. Variants were filtered based on frequency and functional class. Those selected were validated by Sanger sequencing. Genes carrying selected variants were prioritized to relate these genes with those already known to be linked to bAVM development. Most of the prioritized genes showed a correlation with the TGF-ßNotch signaling and vessel morphogenesis. However, two novel pathways related to cilia morphogenesis and ion homeostasis were enriched in mutated genes. These results suggest novel insights on sporadic bAVM onset and confirm its genetic heterogeneity. The high frequency of germline variants in genes related to TGF-ß signaling allows us to hypothesize bAVM as a complex trait resulting from the co-existence of low-penetrance loci. Deeper knowledge on bAVM genetics can improve personalized diagnosis and can be helpful with genotype-phenotype correlations.
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Células Endoteliales/metabolismo , Mutación de Línea Germinal , Homeostasis , Malformaciones Arteriovenosas Intracraneales/diagnóstico , Malformaciones Arteriovenosas Intracraneales/genética , Transducción de Señal , Biología Computacional/métodos , Ontología de Genes , Estudios de Asociación Genética , Predisposición Genética a la Enfermedad , Humanos , Reproducibilidad de los Resultados , Análisis de Secuencia de ADN , Secuenciación del ExomaRESUMEN
BACKGROUND AND PURPOSE: Wide-necked brain aneurysms therapy remains a challenge for neurointerventionalists, mainly for the high recurrence rate. Low-profile stents make feasible the treatment of these aneurysms. In our multicenter series we analyzed clinical and angiographic results of Neuroform Atlas stent-assisted coiling. MATERIALS AND METHODS: From January 2016 to March 2017, 113 wide-necked aneurysms were discovered with CTA, MRA and DSA. The Atlas stent-assisted coiling procedures were performed under general anesthesia with sequential or jailing techniques. Six months follow-up DSA was performed to assess the recurrence rate through the modified Raymond-Roy occlusion scale (RROC). Moreover, patients were evaluated clinically to analyse the degree of disability according to the mRS. MRI was performed at 12 months evaluating both the cerebral tissue and the vessels. RESULTS: In all the procedures it was feasible to navigate the Neuroform Atlas to the goal vessel and deploy the stent across the aneurysmal neck. Intra-procedural complications account for the 6.2% (7/113). The immediate occlusion rate was RROC 1 in 88%, 2 in 9% and 3 in 3% of cases. The 6 months clinical data showed mRS Score 0-1 in 96.5% of patients; 3 patients died of complications related to SAH. The 12 months follow-up showed RROC of 1 in 82%, 2 in 13% and 3 in 5% of cases. No aneurysm has been retreated. CONCLUSIONS: In our multicenter experience the Neuroform Atlas stent assisted-coiling has shown to be a safe and effective technique for the treatment of wide-necked intracranial aneurysms with encouraging clinical and angiographic results.
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Embolización Terapéutica/métodos , Aneurisma Intracraneal/diagnóstico por imagen , Aneurisma Intracraneal/terapia , Stents , Adulto , Anciano , Anciano de 80 o más Años , Angiografía de Substracción Digital , Angiografía Cerebral , Angiografía por Tomografía Computarizada , Femenino , Humanos , Italia , Angiografía por Resonancia Magnética , Masculino , Persona de Mediana Edad , Inhibidores de Agregación Plaquetaria/administración & dosificación , Sistema de Registros , Estudios RetrospectivosRESUMEN
Posterior reversible encephalopathy syndrome (PRES) is an encephalopathy characterized by a rapid onset of symptoms including headache, seizures, confusion, blurred vision, and nausea associated with a typical magnetic resonance imaging appearance of reversible subcortical vasogenic edema prominent and not exclusive of parieto-occipital lobes. Vasogenic edema is caused by a blood-brain barrier leak induced by endothelial damage or a severe arterial hypertension exceeding the limits of cerebral blood flow autoregulation. Although the exact pathophysiological mechanism is still unclear, frequent conditions that may induce PRES include severe hypertension, eclampsia/pre-eclampsia, acute kidney diseases and failure, immunosuppressive therapy, solid organ, or bone marrow transplantation. Conversely to other conditions, which may induce PRES, the link between severe infection or sepsis and PRES, often associated with gram-positive bacteria, is still poorly understood and less well known. Clinicians from multiple disciplines, such as neurologists and internists, may encounter during their profession patients with severe infection or sepsis and should consider the possible association between PRES and these conditions. We systematically reviewed the literature about this association in order to provide a helpful clinical insight of such complex pathophysiological mechanism, highlighting the importance of recognizing PRES in such a complex clinical scenario.
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Infecciones/fisiopatología , Síndrome de Leucoencefalopatía Posterior/fisiopatología , HumanosRESUMEN
Pseudoaneurysm is an abnormal dilation of an artery that could be caused either by iatrogenic or traumatic events and it is associated with high rupture risk. Pseudoaneurysm rarely involves internal maxillary artery. Computed tomography angiography and digital subtraction angiography are essential tools to perform a proper diagnosis and treatment of pseudoaneurysms. The authors described 2 different cases of internal maxillary artery pseudoaneurysm, treated by different embolization approaches. The first case was treated by a well-known arterial catheterism technique, whereas the second one was performed by an uncommon approach with a direct percutaneous puncture.
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Aneurisma Falso/terapia , Embolización Terapéutica/métodos , Arteria Maxilar , Adolescente , Adulto , Aneurisma Falso/diagnóstico por imagen , Aneurisma Falso/etiología , Angiografía de Substracción Digital , Humanos , MasculinoRESUMEN
INTRODUCTION: Eligibility for endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) depends, amongst other factors, on CT- or MR-based scores. The aim of this study was to investigate the role of Alberta Stroke Program Early CT score based on diffusion weighted imaging (MR-ASPECT) in the assessment of brain damage pre-EVT, patient selection for EVT and outcome. MATERIALS AND METHODS: We included in this study patients with National Institute of Health stroke score (NIHSS) at admission ≥ 8, MR-ASPECT ≥ 5 and anterior AIS, who were treated with EVT in our hospital. All patients were clinically evaluated at admission, post-EVT, discharge and at 3-month follow-up. We used MR-ASPECT to establish infarct core extension at admission. We evaluated ASPECT score at admission (CT-ASPECT-IN), 24 h after EVT and at discharge, NIHSS, modified Ranking Scale (mRS), Thrombolysis in Cerebral Infarction scale (TICI), onset-to-intervention-delay (OTID) and Collateral Circulation Score (CCS). RESULTS: 68 patients (mean age 78 ± 11.9 years) were included in this study. 54.4 and 64.7% of patients had strong clinical improvement after 24 h from EVT and at discharge, respectively. NIHSS evaluated 24 h after EVT correlated with CCS, TICI and OTID. We observed a favourable outcome (mRS 0-2) in 52.9% of patients at 3-month follow-up. MR-ASPECT score correlated with post-EVT outcome better than CT-ASPECT-IN scores. CONCLUSION: MR-ASPECT score based on diffusion weighted imaging is useful for the selection of patients with AIS that can have a favourable outcome from EVT. A prompt EVT has huge impact on patient outcome.
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Isquemia Encefálica/diagnóstico por imagen , Isquemia Encefálica/cirugía , Imagen de Difusión por Resonancia Magnética/métodos , Procedimientos Endovasculares/métodos , Selección de Paciente , Accidente Cerebrovascular/diagnóstico por imagen , Accidente Cerebrovascular/cirugía , Trombectomía/métodos , Tomografía Computarizada por Rayos X/métodos , Anciano , Femenino , Humanos , Masculino , Resultado del TratamientoRESUMEN
BACKGROUND AND OBJECTIVES: Pompe disease is a rare metabolic disorder due to lysosomal alpha-glucosidase (GAA) deficiency. It is considered as a multi-systemic disease since, although glycogen accumulation is largely prominent in heart, skeletal and respiratory muscles, other organs can also be affected. As regards the vascular system, few reports have documented cerebrovascular malformations in Pompe patients. The aim of this study was to define the presence and type of intracranial arterial abnormalities in a cohort of late onset Pompe disease (LOPD) patients. METHODS: We have studied 21 LOPD patients with cerebral CT angiography (CTA), using maximum intensity projection and volume rendering technique for 3D-image reconstruction. RESULTS: We found intracranial arterial abnormalities in 13/21 patients (62 %), of whom: 2/21 patients (9.5 %) showed an unruptured intracranial aneurysm (respectively 2 and 4 mm), 10/21 (47 %) had a vertebrobasilar dolichoectasia (VBD) and 1/21 a basilar artery fenestration. Signs of lacunar encephalopathy (insular, capsular and frontal subcortical lesions) were detected in 13/21 patients (62 %) and this correlated with the presence of respiratory impairment (p = 0.017). CONCLUSIONS: These findings differ from what has been previously observed in healthy, aged-matched populations and confirm that cerebral arteries abnormalities, mainly involving the posterior circle, are not so rare in LOPD patients and are often accompanied by a lacunar encephalopathy that might represent a hypoxic-ischemic origin. A CTA or an MRA is recommended, in LOPD patients, for early detection of cerebrovascular malformations as they could lead to life-threatening events such as sub-arachnoid haemorrhage or brainstem compression.
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Arterias/anomalías , Arterias/patología , Enfermedad del Almacenamiento de Glucógeno Tipo II/diagnóstico por imagen , Enfermedad del Almacenamiento de Glucógeno Tipo II/patología , Enfermedades Vasculares/diagnóstico , Enfermedades Vasculares/patología , Adolescente , Adulto , Edad de Inicio , Anciano , Arterias/metabolismo , Femenino , Enfermedad del Almacenamiento de Glucógeno Tipo II/metabolismo , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Vasculares/metabolismo , Adulto Joven , alfa-Glucosidasas/metabolismoRESUMEN
INTRODUCTION: The need to improve surgical efficacy in patients affected by high-grade gliomas has led to development of advanced pre-surgical MRI-based techniques such as tractography. This study investigates pre-surgical planning of optic radiations (ORs) in patients affected by occipito-temporo-parietal high-grade gliomas, by means of constrained spherical deconvolution (CSD) and diffusion tensor imaging (DTI) tractography. METHODS: Twelve patients with occipito-temporo-parietal high-grade gliomas were recruited and analyzed using a 3 T MRI scanner. Diffusion-weighted imaging (DWI) was conducted with 64 gradient diffusion directions. OR alterations were assessed qualitatively and quantitatively to evaluate the effectiveness of CSD- and DTI-based pre-surgical planning. RESULTS: CSD-based tractography provided better qualitative evaluation of affected white matter tracts when compared to DTI; by thresholding tractographic probabilistic maps coming from all reconstructions, we detected, at the highest cutoff level, OR involvement in 75 % of patients (vs 41.67 % of patients with probabilistic DTI). Quantitative analysis of diffusion parameters revealed a statistically significant decrease in fractional anisotropy (FA) in the affected side following CSD-based reconstructions; on the contrary, DTI-based reconstructions did not show any significant quantitative alteration. CONCLUSION: Our results showed improvement in pre-surgical planning of high-grade gliomas involving ORs with use of CSD-based tractography. This technique provided more useful information regarding the white matter spatial relationship with brain neoplasm and its involvement in the glioma, when compared to DTI. Using CSD model for OR evaluation may optimize safe surgical resection margins, helping to reduce risk of post-operative visual deficits.
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Neoplasias Encefálicas/diagnóstico por imagen , Neoplasias Encefálicas/patología , Imagen de Difusión Tensora/métodos , Glioma/diagnóstico por imagen , Glioma/patología , Vías Visuales/diagnóstico por imagen , Vías Visuales/patología , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Imagenología Tridimensional/métodos , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
The purpose of this study is to describe our series of nine unclippable and uncoilable ruptured aneurysms in eight patients treated by microsurgical wrapping with autologous muscle. Records were retrospectively reviewed for rebleeding rate, morbidity and mortality, changes in size or the aneurysm's configurations, and inflammatory reaction. We conducted a Medline search in the post-microsurgical era, excluding patients in whom wrapping was part of the aneurysm treatment in combination with clipping or coiling. The surgically related morbidity was 12.5%. Global mortality rate was 25% due to vasospasm (one case) and rebleeding (one case). Six patients are still alive. Rebleeding rate was 14.3% within 6 months; then, it was zero. Glasgow outcome scale (GOS) score at discharge was 1 and 4 in one patient, respectively, and 5 in the remaining six. Mean clinical follow-up was 126 months. GOS at last follow-up was 4 and 5 in 50% of patients, respectively. Mean mRS score was 0.8 at 2 months, and 2.4 at 12 months. Follow-up MR demonstrated persistence of the aneurysm's sac, without changes in size and configuration. Patients did not describe or exhibit symptoms attributable to complications inherent to the use of muscle. Microsurgical muscle-wrapping of ruptured intracranial aneurysm is safe, is associated with a low rate of acute and delayed postoperative complications and rebleeding, and could be a valid alternative for unclippable and non-amenable to endovascular procedure ruptured aneurysms.
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Aneurisma Roto/cirugía , Procedimientos Endovasculares/métodos , Aneurisma Intracraneal/cirugía , Microcirugia/métodos , Músculo Liso Vascular/trasplante , Procedimientos Neuroquirúrgicos/métodos , Adulto , Anciano , Anciano de 80 o más Años , Aneurisma Roto/mortalidad , Imagen Eco-Planar , Femenino , Estudios de Seguimiento , Escala de Consecuencias de Glasgow , Humanos , Aneurisma Intracraneal/mortalidad , Angiografía por Resonancia Magnética , Masculino , Persona de Mediana Edad , Prevención Secundaria , Hemorragia Subaracnoidea/mortalidad , Hemorragia Subaracnoidea/cirugía , Análisis de Supervivencia , Resultado del TratamientoRESUMEN
We report the CT and MR characteristics of a newborn with a rare, complex malformation characterised by a large rhinopharyngeal and oropharyngeal enterogenous cyst, associated with an osseous defect of the basiocciput, called canalis basilaris medianus (CBM). A partial herniation of the bulb was demonstrated through the bony defect on the midline. The enterogenous cyst occupied the rhinopharynx and oropharynx, narrowing the pharyngeal lumen and making it difficult for the introduction of an orotracheal tube.
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Quistes/diagnóstico , Quistes/etiología , Hueso Occipital/anomalías , Hueso Occipital/diagnóstico por imagen , Enfermedades Faríngeas/diagnóstico , Enfermedades Faríngeas/etiología , Diagnóstico Diferencial , Femenino , Humanos , Recién Nacido , Hueso Occipital/patología , RadiografíaRESUMEN
PURPOSE: The aim of this study was to evaluate the advantages and limits of virtual magnetic resonance techniques in planning surgery for microvascular decompression in patients with neurovascular conflict. MATERIALS AND METHODS: Between December 2010 and December 2011, we prospectively observed 32 patients (30 with trigeminal neuralgia and two with hemifacial spasm), with a suspected clinical diagnosis of neurovascular conflict. To assess the contact between nerve and vessel, magnetic resonance imaging (MRI) by three-dimensional (3D) constructive interference in steady state (CISS) and high-resolution MR angiography (MRA) were performed in all cases. Moreover, we performed presurgical simulation of microvascular decompression using MR two-dimensional image fusion and virtual cisternography. The neuroradiological findings were compared with the surgical findings. RESULTS: In all cases, we demonstrated the anatomical relations between cranial nerves and offending vessels with an optimal correlation between radiological and surgical patterns. CONCLUSIONS: Advanced virtual MRI techniques, such as image fusion and virtual cisternography, are able to depict the complex anatomical relationships between neural and vascular structures within the cisternal spaces of the skull base. These techniques can be considered an optimal presurgical tool to support traditional MRI evaluation of this region.
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Nervios Craneales/anatomía & histología , Espasmo Hemifacial/cirugía , Interpretación de Imagen Asistida por Computador/métodos , Imagen por Resonancia Magnética/métodos , Cirugía Asistida por Computador/métodos , Neuralgia del Trigémino/cirugía , Interfaz Usuario-Computador , Adulto , Anciano , Descompresión Quirúrgica , Femenino , Humanos , Imagenología Tridimensional , Angiografía por Resonancia Magnética , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Resultado del TratamientoRESUMEN
On general regular simplicial partitions T of bounded polytopal domains ΩâRd, d∈{2,3}, we construct exact neural network (NN) emulations of all lowest order finite element spaces in the discrete de Rham complex. These include the spaces of piecewise constant functions, continuous piecewise linear (CPwL) functions, the classical "Raviart-Thomas element", and the "Nédélec edge element". For all but the CPwL case, our network architectures employ both ReLU (rectified linear unit) and BiSU (binary step unit) activations to capture discontinuities. In the important case of CPwL functions, we prove that it suffices to work with pure ReLU nets. Our construction and DNN architecture generalizes previous results in that no geometric restrictions on the regular simplicial partitions T of Ω are required for DNN emulation. In addition, for CPwL functions our DNN construction is valid in any dimension d≥2. Our "FE-Nets" are required in the variationally correct, structure-preserving approximation of boundary value problems of electromagnetism in nonconvex polyhedra ΩâR3. They are thus an essential ingredient in the application of e.g., the methodology of "physics-informed NNs" or "deep Ritz methods" to electromagnetic field simulation via deep learning techniques. We indicate generalizations of our constructions to higher-order compatible spaces and other, non-compatible classes of discretizations, in particular the "Crouzeix-Raviart" elements and Hybridized, Higher Order (HHO) methods.
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Redes Neurales de la Computación , Simulación por ComputadorRESUMEN
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.
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Revascularización Cerebral , Enfermedad de Moyamoya , Arteria Carótida Interna/cirugía , Angiografía Cerebral/métodos , Revascularización Cerebral/métodos , Circulación Cerebrovascular , Humanos , Enfermedad de Moyamoya/complicaciones , Enfermedad de Moyamoya/diagnóstico por imagen , Enfermedad de Moyamoya/cirugíaRESUMEN
Hypoxic ischemic encephalopathy is one of the major causes of neonatal death and neurological disability in the child, and represents the most common birth injury claim. Intrapartum asphyxia often leads to several long-term sequalae, such as cerebral palsy and/or developmental delay, epilepsy. Through the neuroimaging it's possible to identify and define the different lesioned pictures and provide useful elements to establish the moment in which the damage occurred; indeed, timing of injury is a key element in the legal arena. Magnetic resonance imaging (MRI) is emerging as one of the most important tools in identifying the etiologic of neonatal encephalopathy as well as in predicting long-term outcomes. The aim of this study is to evaluate all MRI tests performed in a group of infants and young patients with possible neonatal encephalopathy, in order to determine the role of MRI in perinatal hypoxic-ischemic damage and the specific patterns that can point towards a diagnosis of the time of the damage's onset. Another goal is to assess the role of MRI in cases subject to legal-medical ligation. Since the advent of hypothermic neuroprotection, new malpractice allegations have arisen, including the failure to initiate cooling in a timely manner. In all cases, documentation of the status of the baby at birth, including a thorough neurologic exam, can be extremely helpful to the later defence of a malpractice claim, which might occur years later.
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Medicina Legal , Hipoxia-Isquemia Encefálica/diagnóstico por imagen , Hipoxia-Isquemia Encefálica/patología , Imagen por Resonancia Magnética , Neuroimagen/métodos , Asfixia Neonatal/diagnóstico por imagen , Asfixia Neonatal/patología , Femenino , Humanos , Lactante , Recién Nacido , Italia/epidemiología , MasculinoRESUMEN
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.
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Melanosis , Síndromes Neurocutáneos , Niño , Humanos , Imagen por Resonancia Magnética , Síndromes Neurocutáneos/diagnóstico por imagen , NeuroimagenRESUMEN
(1) Although guidelines about the use of MRI sequences for Multiple Sclerosis (MS) diagnosis and follow-up are available, variability in acquisition protocols is not uncommon in everyday clinical practice. The aim of this study was to evaluate the real-world application of MS imaging guidelines in different settings to clarify the level of adherence to these guidelines. (2) Via an on-line anonymous survey, neuroradiologists (NR) were asked about MRI protocols and parameters routinely acquired when MS patients are evaluated in their center, both at diagnosis and follow-up. Furthermore, data about report content and personal opinions about emerging neuroimaging markers were also retrieved. (3) A total of 46 participants were included, mostly working in a hospital or university hospital (80.4%) and with more than 10 years of experience (47.9%). We found a relatively good adherence to the suggested MRI protocols regarding the use of T2-weighted sequences, although almost 10% of the participants routinely acquired 2D sequences with a slice thickness superior to 3 mm. On the other hand, a wider degree of heterogeneity was found regarding gadolinium administration, almost routinely performed at follow-up examination (87.0% of cases) in contrast with the current guidelines, as well as a low use of a standardized reporting system (17.4% of cases). (4) Although the MS community is getting closer to a standardization of MRI protocols, there is still a relatively wide heterogeneity among NR, with particular reference to contrast administration, which must be overcome to guarantee an adequate quality of patients' care in MS.
RESUMEN
Temozolomide (TMZ) is an alkylating chemotherapeutic agent that has recently been used in some cases as a new therapeutic tool for pituitary carcinomas and aggressive pituitary adenomas. In this report, we present the case of effective TMZ treatment in a 42-year-old man with ACTH-secreting carcinoma. The tumor grew progressively over 4 years, from 2.2 to 31.1 cm³, despite three surgical approaches and γ-knife treatment. Ki-67 increased from 2 to 18%. An intradural metastasis at the foramen magnum was detected by MRI after the third operation. Thereafter, four cycles of 5-day TMZ administration (200 mg/m²/day during the first, and 150 mg/m²/day during the following cycles) induced dramatic tumor size reduction (>90%). Clinical conditions improved progressively and, after 17 months from the beginning of TMZ administration, the patient is still alive. The treatment was well tolerated except for a transient thrombocytopenia (grade 4 WHO).