Spectral Signal Density of Carotid Plaque Using Dual-Energy Computed Tomography.

BACKGROUND AND PURPOSE: Plaque characterization using virtual monochromatic imaging derived from dual-energy computed tomography (CT) angiography requires the determination of normal signal density values of each plaque component. We sought to explore the signal density values of carotid plaque components using dual-energy compared to conventional single-energy CT angiography (CTA), and to establish the energy level with the largest differences between plaque components. METHODS: The present prospective study involved consecutive patients referred for carotid artery evaluation by CTA. Two scans (single-energy and dual-energy CTA) were performed in all patients, and a single radiologist analyzed the data. Single-source dual-energy CTA allowed the generation of virtual monochromatic images from 40 to 140 keV. RESULTS: A total of 35 internal carotid artery lesions were examined in 20 symptomatic patients. The mean age was 72.3 ± 6.7 years, and 9 (45%) patients were male. Internal carotid artery geometrical variables including lumen area (P = .96), vessel area (P = .97), and percent area stenosis (P = .99) did not differ between groups (single-energy CTA, and dual-energy CTA at 40, 70, 100, and 140 keV). Differences between signal densities of different tissues were largest at 40 keV (calcium/lumen, P < .0001; fat/noncalcified, P < .0001). CONCLUSIONS: In the present pilot investigation, virtual monochromatic imaging at low-energy levels derived from dual-energy CTA allowed the largest differences in attenuation levels between tissues, without affecting vessel or plaque geometry.

[Crossed cerebellar diaschisis. Study of a patient by magnetic resonance imaging and positron emission tomography]. / Diasquisis cerebelosa cruzada. Estudio de una paciente con resonancia magnetica y tomografia por emision de positrones.

INTRODUCTION: Crossed cerebellar diaschisis is a functional deficit in an area that is remote from that of a supratentorial brain lesion, although the two are anatomically and functionally connected. Deactivation of the contralateral cerebellar hemisphere occurs and is believed to be caused by a transneuronal metabolic depression of the cortico-ponto-cerebellar pathway. A reduction in the blood flow in the brain takes place and this gives rise to a diminished oxygenation of the cerebellar hemisphere. This finding can be evaluated by different functional imaging methods. CASE REPORT: A 32-year-old female, without any relevant events in her personal history, presented an extensive supra-tentorial ischaemic lesion on the right-hand side. An MR angiography scan was performed, in which the homolateral middle cerebral artery and internal carotid artery were not identified. With no specific causation and suspecting a probable case of vasculitis (two days after the first ischaemic episode, the patient suffered another one in the left-hand occipital area, although this time it was smaller and clinically asymptomatic), a positron emission tomography/computerised tomography (PET/CT) scan was performed. The results revealed hypoenhancement of the radiotracer in the contralateral cerebellar hemisphere, which was interpreted as hypometabolism. CONCLUSIONS: Determined by a possible prognostic value in the presence of crossed cerebellar diaschisis in supratentorial vascular episodes, with respect to the final clinical outcome of the patients, it is interesting to take this possibility into account when evaluating patients with an acute cerebrovascular accident, either by means of PET/CT, MR imaging (perfusion) or CT (perfusion).

Diasquisis cerebelosa cruzada. Estudio de una paciente con resonancia magnética y tomografía por emisión de positrones / Crossed cerebellar diaschisis. Study of a patient by magnetic resonance imaging and positron emission tomography

La diasquisis cerebelosa cruzada es una deficiencia funcional en un área remota a la de una lesión cerebral supratentorial, pero anatómica y funcionalmente conectadas. Se produce una desactivación del hemisferio cerebeloso contralateral, y se considera que la causa una depresión metabólica transneuronal de la vía corticopontocerebelosa. Existe una reducción del flujo sanguíneo cerebral y, por consiguiente, de la oxigenación del hemisferio cerebeloso. Este hallazgo puede evaluarse a través de diferentes métodos de imágenes funcionales. Caso clínico. Mujer de 32 años, sin antecedentes personales relevantes, que presentó una extensa lesión isquémica supratentorial derecha. Se estudió mediante angiorresonancia, en la que no se identificaron la arteria cerebral media y la arteria carótida interna homolaterales. Sin etiología específica, pensando en una probable vasculitis (dos días después del inicial, la paciente sufrió otro episodio isquémico en el área occipital izquierda, de menor tamaño y clínicamente asintomático), se realizó una tomografía por emisión de positrones/tomografía computarizada (PET/TC) y se observó hipocaptación del radiotrazador del hemisferio cerebeloso contralateral, interpretado como hipometabolismo. Conclusión. En función de un posible valor pronóstico en la presencia de diasquisis cerebelosa cruzada en episodios vasculares supratentoriales, con respecto al resultado clínico final de los pacientes, es interesante tener presente esta posibilidad en la evaluación de pacientes con accidente cerebrovascular agudo, ya sea mediante PET/TC, resonancia magnética (perfusión) o TC (perfusión) (AU)

Introduction. Crossed cerebellar diaschisis is a functional deficit in an area that is remote from that of a supratentorial brain lesion, although the two are anatomically and functionally connected. Deactivation of the contralateral cerebellar hemisphere occurs and is believed to be caused by a transneuronal metabolic depression of the cortico-ponto-cerebellar pathway. A reduction in the blood flow in the brain takes place and this gives rise to a diminished oxygenation of the cerebellar hemisphere. This finding can be evaluated by different functional imaging methods. Case report. A 32-year-old female, without any relevant events in her personal history, presented an extensive supratentorial ischaemic lesion on the right-hand side. An MR angiography scan was performed, in which the homolateral middle cerebral artery and internal carotid artery were not identified. With no specific causation and suspecting a probable case of vasculitis (two days after the first ischaemic episode, the patient suffered another one in the left-hand occipital area, although this time it was smaller and clinically asymptomatic), a positron emission tomography/computerised tomography (PET/CT) scan was performed. The results revealed hypoenhancement of the radiotracer in the contralateral cerebellar hemisphere, which was interpreted as hypometabolism. Conclusions. Determined by a possible prognostic value in the presence of crossed cerebellar diaschisis in supratentorial vascular episodes, with respect to the final clinical outcome of the patients, it is interesting to take this possibility into account when evaluating patients with an acute cerebrovascular accident, either by means of PET/CT, MR imaging (perfusion) or CT (perfusion) (AU)

White matter relapsing remitting disease: "Susac's syndrome"-An underdiagnosed entity.

Susac's syndrome is a treatable microangiopathy of unknown etiology affecting arterioles of the brain, retina, and cochlea. The typical clinical manifestation is the triad of encephalopathy, visual loss, and sensorineural hearing loss. One or more of these features may not be present at onset and therefore Susac's syndrome's diagnosis may be difficult. We describe the clinical presentation, diagnostic tests, and treatment of three cases diagnosed and treated at our institution.

Cuantificación del signo de la arteria cerebral media hiperdensa con TCMD / Quantification of hyperdense middle cerebral artery sign by multidetector computed tomography (MDCT).

Objetivos. Obtener una cuantificación absoluta y relativa de la densidad en el signo de la arteria cerebral media (ACM) con el fin de lograr un valor objetivo para el diagnóstico temprano de isquemia cerebral aguda con TCMD. Materiales y Métodos. Se incluyeron 40 pacientes, 20 con sospecha de isquemia cerebral aguda (edad media 73,4 años) y 20 pacientes controles (edad media 71,2 años, p=0,63), que se realizaron TC cerebral con un equipo de 64 filas de detectores. La cuantificación absoluta se realizó midiendo la densidad en UH en el segmento de la ACM visualmente de mayor densidad. También se midió la densidad en el mismo segmento de la ACM contralateral para calcular la diferencia entre ambas arterias (cuantificación relativa). Resultados. En pacientes casos, la densidad media de la ACM afectada (62,5 UH, IC 99%: 46,2-78,7) fue mayor que la de la ACM contralateral (39,3 UH, IC 99%: 33,3-45,3) (p=0,0004) y también fue mayor en comparación con la ACM en pacientes controles (44,7 UH, IC 99%: 37,4-52) (p=0,0045). En la cuantificación relativa, la diferencia media entre la densidad de la ACM afectada y la de ACM contralateral en los pacientes casos fue de 23,2 UH (IC 95%: 11,7-34,7), mientras que, en pacientes controles, la diferencia media entre la densidad de la ACM derecha y la ACM izquierda fue 5,2 UH (IC 95%: 2,4-8,4) (diferencia: 17,8 UH, p=0,0032, IC 95%: 6,8-28,8). Conclusión. Mostramos diferencias significativas (absolutas y relativas) en la densidad de la ACM en pacientes con sospecha de isquemia cerebral aguda en comparación con sujetos normales.

Purposes. To obtain absolute and relative quantification values of density in the middle cerebral artery (MCA) sign, in order to obtain an objective value for an early diagnosis of acute ischemic stroke using MDCT. Material and Methods. Forty adult patients, 20 with suspected diagnosis of acute ischemic stroke (mean age: 73.4 years) and 20 controls (mean age: 71.2 years, p=0.63), underwent brain CT scans with a 64-row multi-detector scanner (Brilliance 64; Philips Medical Systems). Absolute quantitative analysis was assessed by tracking tissue density of the MCA segment using region of interests. For relative quantification, density in the same segment of the contra- lateral MCA was measured to calculate the difference between both arteries. Results. In cases, mean density of affected MCA (62.5 HU, 99% CI: 46.2 - 78.7) was greater than that of the contra-lateral MCA segments (39.3 HU, 99% CI: 33.3-45.3) (p<0.0004) and also greater than that of controls (44.7 HU, 99% CI: 37.4-52) (p=0.0045). In relative quantification, the mean difference between density of the affected MCA and that of contra-lateral MCA in cases was 23.2 HU (95% CI: 11.7-34.7), while in controls the mean difference between the right MCA density and the left MCA density was 5.2 HU (95% CI: 2.4-8.4) (difference: 17.8 HU, p = 0.0062, 95% CI: 6.8-28.8). Conclusion. We showed significant (relative and absolute) differences in MCA density in patients with suspected acute ischemic stroke as compared to normal subjects.

Tumores oligodendrogliales: correlación entre el genotipo tumoral e imágenes de perfusión por RM / Oligodendroglial tumors: correlation between tumor genotype and perfusion magnetic resonance imaging

Objetivo: realizar una evaluación retrospectiva respecto de la correlación entre la técnica de perfusión (PWI) por resonancia magnética (RM), el volumen sanguíneo cerebral relativo (VSCr) y el genotipo tumoral, en pacientes con neoplasias oligodendrogliales grado II. Materiales y métodos: once pacientes (7 hombres y 4 mujeres), con un rango de edad entre los 28 y 64 años, con tumores oligodendrogliales (OD) grado II, fueron estudiados con RM convencional y PWI, con la finalidad de obtener un valor de VSCr. Se realizó el análisis genético en todos los pacientes para evaluar el estado de los cromosomas 1p/19q. Resultados: cinco pacientes con tumores ODs grado II (45%) presentaron un VSCr < 1,75 y ausencia de alteraciones en 1p/19q. Tres pacientes tenían oligoastrocitomas (OA), 2 de ellos con alteraciones en 1p/19q y el restante con 1p/19q intacto. Dos de los pacientes con gliomas mixtos, uno con alteración en 1p/19q y el otro con 1p/19q intacto, presentaron un VSCr> 1,75, mientras que en el paciente restante con glioma mixto y deleción en 1p/19q, el VSCr fue de < 1,75. Dos pacientes con ODs grado II presentaron un VSCr> 1,75, uno con 1p/19q intacto y el restante con deleción en 1p/19q. El último paciente presentó un OD grado II con un VSCr< 1,75 y pérdida de 1p/19q. Conclusiones: aproximadamente el 45% de los pacientes con los cromosomas 1p/19q intactos mostró un VSCr< 1,75, lo que sugiere una neoangiogénesis tumoral limitada. Estos hallazgos podrían ser de utilidad para monitorear respuesta a agentes antiangiogénicos. Los estudios realizados en series mayores podrían proporcionar información valiosa antes de la cirugía y contribuir a un mejor manejo de estos pacientes.

Objective: To perform a retrospective assessment of the correlation between perfusion MR imaging, relative cerebral blood volume (rCBV) and genotype in patients with grade II oligodendroglial neoplasms. Materials and methods: Eleven patients (7 men and 4 women), age range: 28-64 years, with grade II oligodendroglial tumors (OD) were studied using conventional MR and perfusion MR imaging (rCBV). Genetic analysis was carried out in all patients to assess -1p/-19q genotype status. Results: Five patients with grade II oligodendroglial tumors (45%) presented rCBV < 1.75 and intact 1p/19q. Three patients had mixed gliomas, two of them had deletion in 1p/19q, and the other presented intact 1p/19 q. rCBV was > 1.75 in two patients and < 1.75 in the other patient. Two patients with grade II oligodendroglioma had an rCBV > 1.75, one with intact 1p/19q, and the other with deletion. The last patient presented a grade II oligodendroglial tumor with rCBV < 1.75 and 1p/19q loss. Conclusions: Approximately 45% of patients with intact 1p/19q showed rCBV < 1.75, suggesting limited tumor neoangiogenesis. These findings could be important for the antiangiogenic therapy follow-up. Studies in larger series could provide valuable information prior to surgery and contribute to a better management of these patients.

Neuro-ophthalmologic complications of syringobulbia.

Syringobulbia is an uncommon condition, usually a late complication of syringomyelia. It has predilection for the dorsolateral region of the medulla leading to damage to vestibular nuclei and their connections, as well as to the descending sympathetic fibers. Oscillopsia, nystagmus, and Horner syndrome are frequent manifestations of syringobulbia. Oscillopsia may be a disturbing symptom for the patient, whereas Horner syndrome is usually an asymptomatic finding. MRI detection of syringomyelia has led to earlier treatment of syringomyelia and prevention of upward extension of the cavity. This probably explains why syringobulbia is less frequently encountered at present. We propose to describe the neuro-ophthalmologic symptoms and signs that may be observed in patients with syringobulbia and the mechanisms involved in their appearance.

Fast awakening from minimally conscious state with apomorphine.

BACKGROUND: Traumatic brain injury (TBI) can induce long-term severe disorders of consciousness. Evidence suggests an underlying dopaminergic deficit. Dopamine agonists may therefore play an important role in recovery of consciousness. OBJECTIVE: To explore the response to continuous subcutaneous administration of apomorphine in a patient who had remained in minimally conscious state for 104 days and to evaluate the anatomical substrate of the effect. DESIGN: A prospective, open-label, daily treatment, dose-escalation single case clinical study, with retrospective diffusion tensor image (DTI) evaluation. RESULTS: On the fist day of treatment, the patient was able to move his limbs on command and answer yes/no questions which had not been the case prior to apomorphine administration. Subsequently there was a full recovery of consciousness and substantial functional recovery that was sustained even after apomorphine discontinuation. At the highest dose, mild dyskinesias were observed. These resolved with a lowering of the dose. DTI demonstrated a decrease of thalamocortical and corticothalamic projections in this MCS patient compared to normal volunteers. CONCLUSION: Although this is an open-label single-patient case report, the data are consistent with the theory that a dopaminergic deficit underlies MCS and that it may be overcome with apomorphine administration.

Fiabilidad diagnóstica de la doble lectura en RM cráneoespinal: evaluación retrospectiva / Diagnostic reliability of the double reading in craniospinal MRI: retrospective evaluation

Objetivo: Evaluar en forma retrospectiva la fiabilidad diagnóstica del sistema de doble lectura en RM craneoespinal a fin de obtener datos que permitan valorar su impacto sobre la calidad del informe final. Material y Métodos: Sobre un total de 13.460 RM craneoespinales realizadas en 2007 se revisaron en forma retrospectiva y aleatoria 450 informes de RM de columna y 900 informes de RM de cráneo. Entre la primera y la segunda lectura se juzgaron unicamente cambios de fondo, es decir aquellos pasibles de modificar la interpretación de las imágenes y consecuentemente, el diagnóstico final. Resultados: Se realizaron modificaciones en 75 informes de columna (17%) y en 115 de cráneo (13%). Conclusión: el sistema de doble lectura modifica de manera significativa la calidad del informe final.

Purpose:The aim of this paper is to evaluate retrospectively the diagnostic reliability of the double reading system in Spinal and Brain MRI. Material and Methods: Along 2007, 13460 Spinal andBrain MRI were performed, we reviewed 450 reports of Spinal MRI and 900 Brain MRI reports.Between the firstand the second report we paid attention only at major modifications that can modify the final diagnosis. Results: We founded major modifications in 75 (17%) of Spinal MRI reports and in 115 (13%) of the MRI brain reports. Conclusion: The double reading system improve significatively the quality of the final report.