RESUMEN
Occlusion of a ventriculoperitoneal shunt system is a potentially life-threatening complication in patients suffering from hydrocephalus. However, there is no imaging established as standard approach in this acute setting. In the present study, we evaluate the use of superb microvascular imaging for investigation of the patency of ventriculoperitoneal shunt systems. Simulation of low flow rates of cerebrospinal fluid through a small diameter CSF shunt system was performed in a dedicated phantom in order to proof the principle of superb microvascular imaging (SMI) being feasible for the measurement of slow CSF flow through the dedicated CSF shunt system. SMI is able to detect low flow rates in CSF shunt systems effectively and fast. Visualization of a Duplex ultrasound flow and Doppler wave pattern in the VP shunt system after the reservoir has been pressed confirms patency. SMI is an effective method for evaluating CSF shunt patency and diagnosing shunt obstruction. This bears the potential to facilitate evaluation of clinically symptomatic VP shunt patients in an acute setting. Further evaluation of ultrasound flow patterns is granted.
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Hidrocefalia , Derivación Ventriculoperitoneal , Humanos , Derivación Ventriculoperitoneal/efectos adversos , Hidrocefalia/diagnóstico por imagen , Hidrocefalia/cirugía , Hidrocefalia/etiología , Angiografía , Simulación por ComputadorRESUMEN
BACKGROUND AND PURPOSE: Functional connectivity studies revealed alterations within thalamic, salience, and default mode networks in restless legs syndrome patients. METHODS: Eighty-two patients with restless legs syndrome (untreated, n = 30; on dopaminergic medication, n = 42; on alpha-2-delta ligands as mono- or polytherapy combined with dopaminergic medication, n = 10), and 82 individually age- and gender-matched healthy controls were studied with resting-state functional magnetic resonance imaging. Connectivity of 12 resting-state networks was investigated with independent component analysis, and network topology was studied with graph methods among 410 brain regions. RESULTS: Patients with restless legs syndrome showed significantly higher connectivity within salience (p = 0.029), executive (p = 0.001), and cerebellar (p = 0.041) networks, as well as significantly lower (p < 0.05) cerebello-frontal communication compared to controls. In addition, they had a significantly higher (p < 0.05) clustering coefficient and local efficiency in motor and frontal regions; lower clustering coefficient in the central sulcus; and lower local efficiency in the central opercular cortex, temporal, parieto-occipital, cuneus, and occipital regions compared to controls. Untreated patients had significantly lower (p < 0.05) cerebello-parietal communication compared to healthy controls. Connectivity between the thalamus and frontal regions was significantly increased (p < 0.05) in patients on dopaminergic medication compared to untreated patients and controls. CONCLUSIONS: Networks with higher intranetwork connectivity (i.e., salience, executive, cerebellar) and lower cerebello-frontal connectivity in the restless legs syndrome patients, as well as lower cerebello-parietal connectivity in untreated patients, correspond to regions associated with attention, response inhibitory control, and processing of sensory information. Intact cerebello-parietal communication and increased thalamic connectivity to the prefrontal regions in patients on dopaminergic medication suggests a treatment effect on thalamus.
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Síndrome de las Piernas Inquietas , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Estudios de Casos y Controles , Corteza Cerebral , Humanos , Imagen por Resonancia Magnética , Síndrome de las Piernas Inquietas/diagnóstico por imagen , Síndrome de las Piernas Inquietas/tratamiento farmacológico , Tálamo/diagnóstico por imagenRESUMEN
OBJECTIVES: We aimed to evaluate the ability of feed-forward neural networks (fNNs) to predict the neurodevelopmental outcome (NDO) of very preterm neonates (VPIs) at 12 months corrected age by using biomarkers of cerebral MR proton spectroscopy (1H-MRS) and diffusion tensor imaging (DTI) at term-equivalent age (TEA). METHODS: In this prospective study, 300 VPIs born before 32 gestational weeks received an MRI scan at TEA between September 2013 and December 2017. Due to missing or poor-quality spectroscopy data and missing neurodevelopmental tests, 173 VPIs were excluded. Data sets consisting of 103 and 115 VPIs were considered for prediction of motor and cognitive developmental delay, respectively. Five metabolite ratios and two DTI characteristics in six different areas of the brain were evaluated. A feature selection algorithm was developed for receiving a subset of characteristics prevalent for the VPIs with a developmental delay. Finally, the predictors were constructed employing multiple fNNs and fourfold cross-validation. RESULTS: By employing the constructed fNN predictors, we were able to predict cognitive delays of VPIs with 85.7% sensitivity, 100% specificity, 100% positive predictive value (PPV) and 99.1% negative predictive value (NPV). For the prediction of motor delay, we achieved a sensitivity of 76.9%, a specificity of 98.9%, a PPV of 90.9% and an NPV of 96.7%. CONCLUSION: FNNs might be able to predict motor and cognitive development of VPIs at 12 months corrected age when employing biomarkers of cerebral 1H-MRS and DTI quantified at TEA. KEY POINTS: ⢠A feed-forward neuronal network is a promising tool for outcome prediction in premature infants. ⢠Cerebral proton magnetic resonance spectroscopy and diffusion tensor imaging can be used for the construction of early prognostic biomarkers. ⢠Premature infants that would most benefit from early intervention services can be spotted at the time of optimal neuroplasticity.
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Encéfalo/diagnóstico por imagen , Discapacidades del Desarrollo/diagnóstico , Imagen de Difusión Tensora/métodos , Interpretación de Imagen Asistida por Computador/métodos , Enfermedades del Prematuro/diagnóstico , Espectroscopía de Resonancia Magnética/métodos , Redes Neurales de la Computación , Encéfalo/fisiopatología , Discapacidades del Desarrollo/fisiopatología , Femenino , Humanos , Lactante , Recién Nacido , Recien Nacido Prematuro , Enfermedades del Prematuro/fisiopatología , Masculino , Valor Predictivo de las Pruebas , Pronóstico , Estudios Prospectivos , Sensibilidad y EspecificidadRESUMEN
OBJECTIVES: To quantitatively assess carpal tunnel syndrome (CTS) with DTI by evaluating two approaches to determine cut-off values. METHODS: In forty patients with CTS diagnosis confirmed by nerve conduction studies (NCs) and 14 healthy subjects (mean age 58.54 and 57.8 years), cross-sectional area (CSA), apparent diffusion coefficient (ADC) and fractional anisotropy (FA) at single and multiple levels with intraobserver agreement were evaluated. RESULTS: Maximum and mean CSA and FA showed significant differences between healthy subjects and patients (12.85 mm2 vs. 28.18 mm2, p < 0.001, and 0.613 vs. 0.524, p=0.007, respectively) (10.12 mm2 vs. 19.9 mm2, p<0.001 and 0.617 vs. 0.54, p=0.003, respectively), but not maximum and mean ADC (p > 0.05). For cut-off values, mean and maximum CSA showed the same sensitivity and specificity (93.3 %). However, mean FA showed better sensitivity than maximum FA (82.6 % vs. 73.9 %), but lower specificity (66.7 % vs. 80 %), and significant correlation for maximum CSA, 97 % (p < 0.01), with good correlation for maximum ADC and FA, 84.5 % (p < 0.01) and 62 % (p=0.056), respectively. CONCLUSIONS: CSA and FA showed significant differences between healthy subjects and patients. Single measurement at maximum CSA is suitable for FA determination. Key Points ⢠DTI showed that FA is stronger than ADC for CTS diagnosis. ⢠Single- and multiple-level approaches were compared to determine FA and ADC. ⢠Single-level evaluation at the thickest MN cross-sectional area is sufficient.
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Síndrome del Túnel Carpiano/diagnóstico por imagen , Imagen de Difusión Tensora/métodos , Adulto , Anciano , Anisotropía , Estudios de Casos y Controles , Femenino , Humanos , Interpretación de Imagen Asistida por Computador/métodos , Masculino , Nervio Mediano/diagnóstico por imagen , Persona de Mediana Edad , Conducción Nerviosa , Variaciones Dependientes del Observador , Sensibilidad y EspecificidadAsunto(s)
Neoplasias Encefálicas/diagnóstico por imagen , Encéfalo/efectos de la radiación , Neoplasias de Cabeza y Cuello/radioterapia , Traumatismos por Radiación/diagnóstico por imagen , Encéfalo/patología , Neoplasias Encefálicas/patología , Humanos , Magnetoterapia , Necrosis/diagnóstico por imagenRESUMEN
METHOD: Functional magnetic resonance imaging (fMRI) is a non-invasive method that has become one of the major tools for understanding human brain function and in recent years has also been developed for clinical applications. PERFORMANCE: Changes in hemodynamic signals correspond to changes in neuronal activity with good spatial and temporal resolution in fMRI. Using high-field MR systems and increasingly dedicated statistics and postprocessing, activated brain areas can be detected and superimposed on anatomical images. Currently, fMRI data are often combined in multimodal imaging, e. g. with diffusion tensor imaging (DTI) sequences. This method is helping to further understand the physiology of cognitive brain processes and is also being used in a number of clinical applications. In addition to the blood oxygenation level-dependent (BOLD) signals, this article deals with the construction of fMRI investigations, selection of paradigms and evaluation in the clinical routine. Clinically, this method is mainly used in the planning of brain surgery, analyzing the location of brain tumors in relation to eloquent brain areas and the lateralization of language processing. PRACTICAL RECOMMENDATIONS: As the BOLD signal is dependent on the strength of the magnetic field as well as other limitations, an overview of recent developments is given. Increases of magnetic field strength (7 T), available head coils and advances in MRI analytical methods have led to constant improvement in fMRI signals and experimental design. Especially the depiction of eloquent brain regions can be done easily and quickly and has become an essential part of presurgical planning.
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Encefalopatías/diagnóstico por imagen , Encefalopatías/fisiopatología , Mapeo Encefálico/tendencias , Encéfalo/fisiopatología , Circulación Cerebrovascular , Imagen de Difusión Tensora/tendencias , Animales , Velocidad del Flujo Sanguíneo , Humanos , Aumento de la Imagen/métodos , Consumo de OxígenoRESUMEN
PURPOSE: Magnetic resonance imaging (MRI) is one of the most important methods for the diagnosis and therapy monitoring of various diseases. Today, magnets up to 3 T are standard. This review will give an overview of the clinical perspectives of ultra-high field MRI, meaning mainly 7 T. METHODS: Literature review with focus on clinical applications of 7 T imaging in neuroscience combined with examples of own studies and perspectives. RESULTS: This high-resolution technique offers the potential to improve certain tissue contrasts and signal in functional (fMRI) and metabolic (MRS) imaging. This overview demonstrates already existing potentials and advantages of the ultra-high magnetic field for central nervous system (CNS) diseases. CONCLUSIONS: Although there are still some technical challenges for brain and spine imaging at 7 T, the method has clear benefit in selected structural, functional, and metabolic imaging.
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Encefalopatías/patología , Encefalopatías/fisiopatología , Encéfalo/patología , Encéfalo/fisiopatología , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Humanos , Aumento de la Imagen/métodos , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
BACKGROUND AND PURPOSE: Dual-energy CT features the opportunity to differentiate among up to 3 different materials because the absorption of x-rays depends on the applied tube voltage and the atomic number of the material. For example, it is possible to distinguish between blood-brain barrier disruption and an intracerebral hemorrhage following treatment for a stroke. The aim of this study was to evaluate whether dual-energy CT is capable of distinguishing intra-arterial contrast agent from residually clotted vessels immediately after endovascular stroke therapy. MATERIALS AND METHODS: Sixteen patients (9 women, 7 men; mean age, 63.6 ± 13.09 years) were examined. Measurements were made on the postinterventional dual-energy CT virtual noncontrast, iodine map, and "weighted" brain window (weighted dual-energy) series. Postinterventional conventional angiography was used as the criterion standard method. RESULTS: A residual clot was found in 10 patients. On the virtual noncontrast series, the Hounsfield attenuation of the clotted arteries was higher than that in the corresponding perfused contralateral arteries (53.72 ± 9.42 HU versus 41.64 ± 7.87 HU; P < .05). The latter had higher absorption values on the weighted dual-energy series than on the virtual noncontrast series (49.37 ± 7.44 HU versus 41.64 ± 7.87 HU; P < .05). The sensitivity for the detection of a residual clot was 90%; the specificity was 83.3%, and the accuracy was 87.5%. Interrater agreement was good (κ = 0.733). CONCLUSIONS: Dual-energy CT may be valuable in the detection of clot persistence or early re-thrombosis without the necessity of additional contrast administration. However, its relevance for the prediction of outcomes remains to be determined in further studies.
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Arterias Cerebrales/patología , Embolia Intracraneal/terapia , Trombosis Intracraneal/terapia , Radiografía Intervencional/métodos , Accidente Cerebrovascular/terapia , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/diagnóstico por imagen , Arterias Cerebrales/diagnóstico por imagen , Hemorragia Cerebral/diagnóstico por imagen , Procedimientos Endovasculares , Femenino , Humanos , Embolia Intracraneal/patología , Trombosis Intracraneal/patología , Masculino , Persona de Mediana Edad , Accidente Cerebrovascular/diagnóstico por imagenRESUMEN
BACKGROUND: In Friedreich's ataxia (FA) the genetically decreased expression of the mitochondrial protein frataxin leads to disturbance of the mitochondrial iron metabolism. Within the cerebellum the dentate nuclei (DN) are primarily affected. Histopathological studies show atrophy and accumulation of mitochondrial iron in DN. Dentate iron content has been suggested as a biomarker to measure the effects of siderophores/antioxidant treatment of FA. We assessed the iron content and the volume of DN in FA patients and controls based on ultra-high-field MRI (7 Tesla) images. METHODS: Fourteen FA patients (mean age 38.1 yrs) and 14 age- and gender-matched controls participated. Multi-echo gradient echo and susceptibility weighted imaging (SWI) sequences were acquired on a 7 T whole-body scanner. For comparison SWI images were acquired on a 1.5 T MR scanner. Volumes of the DN and cerebellum were assessed at 7 and 1.5 T, respectively. Parametric maps of T2 and T2* sequences were created and proton transverse relaxation rates were estimated as a measure of iron content. RESULTS: In FA, the DN and the cerebellum were significantly smaller compared to controls. However, proton transverse relaxation rates of the DN were not significantly different between both groups. CONCLUSIONS: Applying in vivo MRI methods we could demonstrate significant atrophy of the DN in the presence of normal iron content. The findings suggest that relaxation rates are not reliable biomarkers in clinical trials evaluating the potential effect of FA therapy.
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Núcleos Cerebelosos/metabolismo , Núcleos Cerebelosos/patología , Ataxia de Friedreich/diagnóstico , Ataxia de Friedreich/metabolismo , Hierro/metabolismo , Adulto , Atrofia/metabolismo , Atrofia/patología , Cerebelo/metabolismo , Cerebelo/patología , Imagen Eco-Planar/métodos , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: We explored sex differences in the neural mechanisms mediating placebo analgesia in an established visceral pain model involving painful rectal distensions in healthy volunteers. METHODS: N = 15 men and N = 15 women underwent three consecutive functional magnetic resonance imaging sessions during which cued painful rectal distensions were delivered. After an adaptation session, positive expectations were induced with deceptive instructions regarding administration of an analgesic drug (placebo session). In the other session (control), truthful information about an inert substance was given. Sex differences in placebo-induced modulation of neural activation during anticipation and pain were analyzed along with ratings of expected and perceived pain intensity. KEY RESULTS: Placebo-induced reductions in pain ratings were comparable between men and women. At the level of the brain, group comparisons with respect to differences between the placebo and control conditions revealed greater modulation of the posterior insula (regions-of-interest analysis: pFWE < 0.05) and dorsolateral prefrontal cortex (whole-brain analysis: p < 0.001, uncorrected) during pain anticipation in women. During pain, placebo-induced down-regulation of the insula was altered in women compared to men (ROI analysis: pFWE < 0.05). CONCLUSIONS & INFERENCES: Our data provide first evidence supporting sex differences in pain-induced neural modulation during visceral placebo analgesia despite similar placebo-induced reductions in perceived pain intensity. These preliminary findings might contribute to elucidating mechanisms mediating placebo effects in clinical conditions associated with chronic abdominal pain such as in irritable bowel syndrome.
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Percepción del Dolor/efectos de los fármacos , Efecto Placebo , Caracteres Sexuales , Dolor Visceral/psicología , Adulto , Analgesia , Analgésicos/farmacología , Encéfalo/efectos de los fármacos , Encéfalo/fisiología , Femenino , Voluntarios Sanos , Humanos , Imagen por Resonancia Magnética , Masculino , Dimensión del Dolor , Percepción del Dolor/fisiología , Umbral del Dolor , PlacebosRESUMEN
CLINICAL/METHODICAL ISSUE: Cost-intensive measures and procedures, such as also employed in radiology, have far-reaching economic implications in respect to increasing expenditure with limited resources. STANDARD RADIOLOGICAL METHODS: Health technology assessment (HTA) describes the systematic evaluation of medical procedures and technologies which in recent years has been introduced by many countries into healthcare politics. ASSESSMENT: In many cases HTA analyses can be directly implemented into practice as shown by the examples given in this article; however, in the current form of HTA the practical implementation for radiology often presents the problem that the cost-benefit ratio does not yet have a comprehensive view in the HTA report but is limited to a subsection, e.g. current costs versus sensitivity of a method. Since its inception radiology has had a high power of innovation and new developments will also substantially determine the future years. These procedures must not only be evaluated with respect to feasibility but also in the sense of the HTA in the total concept. PRACTICAL RECOMMENDATIONS: In radiology there are also a large number of possibilities for radiologists not only as passive consumers of HTA reports but also to become active participants in this process, an opportunity which should be taken advantage of.
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Tecnología Biomédica/economía , Análisis Costo-Beneficio/métodos , Costos de la Atención en Salud , Modelos Económicos , Radiología/economía , Evaluación de la Tecnología Biomédica/economía , Evaluación de la Tecnología Biomédica/métodos , AlemaniaRESUMEN
PURPOSE: In 2 institutions exposure values were evaluated and compared with the 2010 updated diagnostic reference levels (DRL) and possibilities for decreasing the dose assessed. MATERIALS AND METHODS: Mean exposure values obtained during a 3-month period were calculated for all modalities (X-ray: imaging plate system and digital detector; dual-source 64- and 16- slice spiral CT) as well as examination types were compared to old diagnostic reference levels in addition to DRLs introduced in 2010. Then 10 examinations of all modalities and types were accompanied by a medical physicist and optimized stepwise if necessary. RESULTS: The mean values of X-ray examinations were above DRL. All accompanied examinations were beyond DRL except lateral lumbar spine (LSP) and lateral thoracic X-ray, which were elevated due to statistical outliers from morbidly obese patients or patients with metallic implants. For a-p LSP tube voltage was increased. While image quality was maintained, dose area product (DAP) was reduced by 50% to 123â±â61 cGyâ·âcm² for LSP a-p and 30% for lateral LSP to 229â±â116 cGyâ·âcm². For CT examinations, dose was below DRL. Accompanied examinations of the lumbar spine performed on a 16-slice spiral CT demonstrated a result 68% above DRL with dose length product (DLP) of 840â±â252 cGyâ·âcm. For optimization, pitch and tube voltage were stepwise increased and DLP reduced below DRL. CONCLUSION: Systematic analysis of our internal exposure values on the occasion of adaptation of DRL is crucial for prompt detection of exceeded values independently from assessment by the responsible authority and initiation of proper measures for decreasing exposure dose. Hereby active dose management is attained. KEY POINTS: ⺠Analysis of exposure values for high data volumes obtained from the Radiology Information System (RIS) is possible independent of weight. ⺠Summation of small groups of patients with different weights might result in high exposure values (DRL 70 âkg). ⺠If high exposure values are observed in small groups of patients, individual analysis of examinations is mandatory. ⺠Active dose management can be obtained by an analysis of average exposure of all examinations obtained during a specific observation period. ⺠Potential for optimization of exposure values might be possible even they fall below DRL.
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Aumento de la Imagen/métodos , Interpretación de Imagen Asistida por Computador/métodos , Vértebras Lumbares/diagnóstico por imagen , Dosis de Radiación , Vértebras Torácicas/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Humanos , Aumento de la Imagen/instrumentación , Interpretación de Imagen Asistida por Computador/instrumentación , Valores de Referencia , Tomografía Computarizada Espiral/métodos , Tomografía Computarizada por Rayos X/instrumentaciónRESUMEN
PURPOSE: The purpose of this study was to evaluate the benefits of CT myelography in the DE technique in patients with lumbar osteosynthesis. MATERIALS AND METHODS: In 30 patients a DE-CT scan of the spine with tube voltages of 80âkV and 140âkV was performed and a virtual monochromatic series of 120âkV was generated after intrathecal contrast injection. The impact of metal artifacts on the spinal canal and the spinal foramina was evaluated. The visualization of nerve roots was compared between a VRT series of the dural sac and conventional myelography. RESULTS: With tube voltages of 140âkV, the artifacts were least pronounced. As no overlay disturbance was present, VRT visualization of the nerve roots was more reliable than conventional myelography. CONCLUSION: In patients after osteosynthesis, CT in the DE technique provides minimal artifact disturbance using a tube voltage of 140âkV. "Virtual myelography" seems to be superior to conventional myelography for the evaluation of nerve roots. This could reduce additional conventional radiography, may shorten the entire examination and radiation time and diminish unnecessary painful movements for the patient.
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Fijación Interna de Fracturas/métodos , Mielografía/métodos , Dosis de Radiación , Imagen Radiográfica por Emisión de Doble Fotón/métodos , Estenosis Espinal/diagnóstico por imagen , Estenosis Espinal/cirugía , Tomografía Computarizada por Rayos X/métodos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/cirugía , Masculino , Persona de Mediana Edad , Pronóstico , Protección Radiológica/métodos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Resultado del TratamientoAsunto(s)
Anticuerpos Monoclonales Humanizados/efectos adversos , Encéfalo/efectos de los fármacos , Encéfalo/patología , Leucoencefalopatía Multifocal Progresiva/inducido químicamente , Leucoencefalopatía Multifocal Progresiva/patología , Imagen por Resonancia Magnética/métodos , Espectroscopía de Resonancia Magnética/métodos , Adulto , Anticuerpos Monoclonales Humanizados/uso terapéutico , Femenino , Humanos , Leucoencefalopatía Multifocal Progresiva/terapia , NatalizumabRESUMEN
Baló's concentric sclerosis (BCS) is an inflammatory demyelinating disease related to multiple sclerosis; its underlying pathology remains unclear. At 7 T MRI in a 19-year-old female BCS patient, microhaemorrhages and ectatic veins were found in T2 hyperintense regions, features which have not been previously reported in conjunction with BCS, and these findings may support the view that vascular pathology plays a role in BCS. MRS data suggest that neuron loss and lipid turnover still took place months after a remission. Plasma exchange was effective in treating a relapse with severe motor deficits, and the off-label use of natalizumab was successful in maintaining remission in this patient.
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Esclerosis Cerebral Difusa de Schilder/patología , Imagen por Resonancia Magnética/métodos , Anticuerpos Monoclonales Humanizados/uso terapéutico , Encéfalo/patología , Femenino , Humanos , Factores Inmunológicos/uso terapéutico , Natalizumab , Adulto JovenRESUMEN
Sequelae in children following cerebellar tumor removal surgery are well defined, and predictors for poor recovery include lesions of the cerebellar nuclei and the inferior vermis. Dynamic reorganization is thought to promote functional recovery in particular within the first year after surgery. Yet, the time course and mechanisms of recovery within this critical time frame are elusive and longitudinal studies are missing. Thus, a group of children and adolescents (n = 12, range 6-17 years) were followed longitudinally after cerebellar surgery and compared to age- and gender-matched controls (n = 11). Patients were examined (1) within the first days, (2) 3 months, and (3) 1 year after surgery. Each time behavioral tests of balance and upper limb motor function, ataxia rating, and a MRI scan were performed. Data were used for subsequent lesion-symptom mapping of cerebellar function. Behavioral improvements continued beyond 3 months, but were not complete in all patients after 1 year. At that time, remaining deficits were mild. Within the first 3 months, cerebellar lesion volumes were notably reduced by vanishing edema. Reduction in edema affecting the deep cerebellar nuclei but not reduction of total cerebellar lesion volume was a major predictor of early functional recovery. Persistent impairment in balance and upper limb function was linked to permanent lesions of the inferior vermis and the deep cerebellar nuclei.
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Astrocitoma/fisiopatología , Astrocitoma/cirugía , Neoplasias Cerebelosas/fisiopatología , Neoplasias Cerebelosas/cirugía , Recuperación de la Función , Adolescente , Astrocitoma/patología , Ataxia Cerebelosa/patología , Ataxia Cerebelosa/fisiopatología , Ataxia Cerebelosa/cirugía , Neoplasias Cerebelosas/patología , Niño , Quiste Dermoide/patología , Quiste Dermoide/fisiopatología , Quiste Dermoide/cirugía , Ependimoma/patología , Ependimoma/fisiopatología , Ependimoma/cirugía , Femenino , Glioblastoma/patología , Glioblastoma/fisiopatología , Glioblastoma/cirugía , Humanos , Estudios Longitudinales , Imagen por Resonancia Magnética , Masculino , Meduloblastoma/patología , Meduloblastoma/fisiopatología , Meduloblastoma/cirugía , Destreza Motora , Equilibrio PosturalRESUMEN
PURPOSE: The aim of this study was to demonstrate the feasibility of cranial nerve (CN II-XII) imaging with 7 Tesla magnetic resonance imaging (MRI). METHODS: In this study four sequences were evaluated in three healthy volunteers using magnetization preparation rapid gradient echo (MPRAGE), constructive interference in steady state (CISS), true fast imaging with steady state precession (TrueFISP) and proton density (PD) T2-weighted turbo spin echo (TSE) sequences. RESULTS: It was found that MPRAGE did not always provide sufficient contrast to delineate in particular small CNs but displayed an overall good identification rate. The T2 sequence was not able to adequately differentiate the small CNs but showed a very good contrast between nerves and cerebrospinal fluid (CSF). As at lower magnetic fields steady state sequences displayed a high identification rate of all CNs in the axial plane but CISS suffered from susceptibility and pulsation artifacts, furthermore it was limited as no parallel imaging could be performed. The TrueFISP technique was reliable in identifying most CNs although suffering from banding artifacts. CONCLUSIONS: The TrueFISP sequence showed superior spatial resolution and contrast in comparison to the other sequences for imaging of CNs at 7 T.
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Algoritmos , Nervios Craneales/anatomía & histología , Interpretación de Imagen Asistida por Computador/métodos , Imagen por Resonancia Magnética/métodos , Neuroimagen/métodos , Adulto , Estudios de Factibilidad , Humanos , Aumento de la Imagen/métodos , Masculino , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Adulto JovenRESUMEN
BACKGROUND: To assess effects of perceived treatment (i.e. drug vs placebo) on behavioral and neural responses to rectal pain stimuli delivered in a deceptive placebo condition. METHODS: This fMRI study analyzed the behavioral and neural responses during expectation-mediated placebo analgesia in a rectal pain model. In N = 36 healthy subjects, the blood oxygen level-dependent (BOLD) response during cued anticipation and painful stimulation was measured after participants were informed that they had a 50% chance of receiving either a potent analgesic drug or an inert substance (i.e., double-blind administration). In reality, all received placebo. We compared responses in subjects who retrospectively indicated that they received the drug and those who believed to have received placebo. KEY RESULTS: 55.6% (N = 20) of subjects believed that they had received a placebo, whereas 36.1% (N = 13) believed that they had received a potent analgesic drug. Subjects who were uncertain (8.3%, N = 3) were excluded. Rectal pain-induced discomfort was significantly lower in the perceived drug treatment group (P < 0.05), along with significantly reduced activation of the insular, the posterior and anterior cingulate cortices during pain anticipation, and of the anterior cingulate cortex during pain (all P < 0.05 in regions-of-interest analyses). CONCLUSIONS & INFERENCES: Perceived treatment constitutes an important aspect in placebo analgesia. A more refined understanding of individual treatment expectations and perceived treatment allocation has multiple implications for the design and interpretation of clinical trials and experimental studies on placebo and nocebo effects.
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Anticipación Psicológica/fisiología , Encéfalo/efectos de los fármacos , Dolor Visceral/psicología , Adulto , Analgésicos/farmacología , Encéfalo/fisiología , Método Doble Ciego , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Masculino , Dimensión del Dolor , Efecto Placebo , Dolor Visceral/tratamiento farmacológicoRESUMEN
BACKGROUND: Functional magnetic resonance imaging (fMRI) studies are increasingly employed in different conscious states. Autogenic training (AT) is a common clinically used relaxation method. The purpose of this study was to investigate the cerebral modulation of pain activity patterns due to AT and to correlate the effects to the degree of experience with AT and strength of stimuli. METHODS: Thirteen volunteers familiar with AT were studied with fMRI during painful electrical stimulation in a block design alternating between resting state and electrical stimulation, both without AT and while employing the same paradigm when utilizing their AT abilities. The subjective rating of painful stimulation and success in modulation during AT was assessed. RESULTS: During painful electrical stimulation without AT, fMRI revealed activation of midcingulate, right secondary sensory, right supplementary motor, and insular cortices, the right thalamus and left caudate nucleus. In contrast, utilizing AT only activation of left insular and supplementary motor cortices was revealed. The paired t-test revealed pain-related activation in the midcingulate, posterior cingulate and left anterior insular cortices for the condition without AT, and activation in the left ventrolateral prefrontal cortex under AT. Activation of the posterior cingulate cortex and thalamus correlated with the amplitude of electrical stimulation. CONCLUSIONS: This study revealed an effect on cerebral pain processing while performing AT. This might represent the cerebral correlate of different painful stimulus processing by subjects who are trained in performing relaxation techniques. However, due to the absence of a control group, further studies are needed to confirm this theory.
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Entrenamiento Autogénico/métodos , Encéfalo/fisiología , Dolor Nociceptivo/terapia , Adulto , Mapeo Encefálico , Corteza Cerebral/fisiología , Estimulación Eléctrica , Femenino , Neuroimagen Funcional , Giro del Cíngulo/fisiología , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Dolor Nociceptivo/fisiopatología , Tálamo/fisiologíaRESUMEN
INTRODUCTION: We assessed sex differences in behavioural and neural responses to rectal pain stimuli in healthy subjects. METHODS: In age- and body mass index-matched healthy subjects (n = 15 men, 15 women), rectal sensory and pain thresholds were assessed with a pressure-controlled barostat device. The blood oxygen level-dependent response during cued anticipation and painful stimulation was measured using functional magnetic resonance imaging (fMRI). Retrospective pain evaluations were accomplished with visual analogue scales. For fMRI data, region-of-interest (ROI) analyses and additional whole-brain analyses were carried out. RESULTS: There were no sex differences in rectal thresholds or pain ratings. ROI analyses revealed comparable distension-induced activation of the thalamus, somatosensory cortex, insula and dorsolateral prefrontal cortex (DLPFC). Only in additional whole-brain analyses did we find increased activation in women in DLPFC and middle temporal gyrus during pain anticipation and in the cerebellum and medial frontal gyrus during pain. A significant inverse association between rectal pain threshold and distension-induced activation in virtually all ROIs was found in women. In men, pain thresholds and insula activation were positively correlated, as were pain ratings and anterior cingulate cortex activation. CONCLUSIONS: Healthy men and women do not differ in behavioural measures of visceral pain sensitivity. The pattern of neural activation is comparable in the majority of pain-processing brain regions, although women may differ in the activation of DLPFC which could reflect sex differences in cognitive-emotional pain regulation. Women with lower pain thresholds showed greater neural responses, which may be relevant in the pathophysiology of visceral hyperalgesia.