Is Diffusion Tensor Imaging a Good Biomarker for Early Parkinson's Disease?

Objectives: To assess white matter abnormalities in Parkinson's disease (PD). Methods: A hundred and thirty-two patients with PD (mean age 60.93 years; average disease duration 7.8 years) and 137 healthy controls (HC; mean age 57.8 years) underwent the same MRI protocol. Patients were assessed by clinical scales and a complete neurological evaluation. We performed a TBSS analysis to compare patients and controls, and we divided patients into early PD, moderate PD, and severe PD and performed an ROI analysis using tractography. Results: With TBSS we found lower FA in patients in corpus callosum, internal and external capsule, corona radiata, thalamic radiation, sagittal stratum, cingulum and superior longitudinal fasciculus. Increased AD was found in the corpus callosum, fornix, corticospinal tract, superior cerebellar peduncle, cerebral peduncle, internal and external capsules, corona radiata, thalamic radiation and sagittal stratum and increased RD were seen in the corpus callosum, internal and external capsules, corona radiata, sagittal stratum, fornix, and cingulum. Regarding the ROIs, a GLM analysis showed abnormalities in all tracts, mainly in the severe group, when compared to HC, mild PD and moderate PD. Conclusions: Since major abnormalities were found in the severe PD group, we believe DTI analysis might not be the best tool to assess early alterations in PD, and probably, functional and other structural analysis might suit this purpose better. However it can be used to differentiate disease stages, and as a surrogate marker to assess disease progression, being an important measure that could be used in clinical trials. HIGHLIGHTS DTI is not the best tool to identify early PDDTI can differentiate disease stagesDTI analysis may be a useful marker for disease progression.

Effect of pulsed electromagnetic field on the consolidation of posterolateral arthrodeses in the lumbosacral spine: a prospective, double-blind, randomized study / Efeito do campo eletromagnético pulsado na consolidação das artrodeses posterolaterais lombossacras: estudo prospectivo, duplo-cego e randomizado / Efecto del campo electromagnético pulsado en la consolidación de artrodesis posterolaterales en la columna lumbosacral: estudio prospectivo, doble ciego, randomizado

ABSTRACT Objective: To assess the effect of pulsed electromagnetic field (PEMF) on the consolidation of instrumented lumbar posterolateral arthrodeses in patients who have been surgically treated for degenerative spine disease. Methods: Forty cases were recruited from 163 consecutive patients undergoing lumbar arthrodesis at the same center. The patients were randomized into two groups of 20 patients: Active Group, who were exposed to PEMF for 4 hours a day for 90 days after surgery, and Inactive Group, who received an identical device, with the same instructions for use but without the ability to generate PEMF. The patients underwent computed tomography scans at 45, 90, 180 and 360 days after surgery to check for the occurrence of arthrodesis at each operated spinal level. Results: In the course of the study, two patients were excluded from each group. There were no significant differences between the groups with respect to age, gender, smoking habit, or the number of vertebral levels included in the arthrodesis. The percentage of consolidation of the vertebral levels increased at 90, 180 and 360 days compared to 45 days (p<0.001) in both groups. The Active Group had a 276% greater chance of consolidation in the vertebral levels (OR = 3.76; 95% CI: 1.39-10.20), regardless of the time of evaluation. Patients in the Active Group presented 16% more consolidation than patients in the inactive group (p=0.018). Conclusions: Post-operative exposure to PEMF following instrumented arthrodesis of the lumbar spine for degenerative spine disease increased consolidation in the first year after surgery.

RESUMO Objetivo: Avaliar o efeito do campo eletromagnético pulsado (CEMP) na consolidação de artrodeses posterolaterais lombares instrumentadas em pacientes que foram tratados cirurgicamente de doença degenerativa da coluna vertebral. Métodos: Quarenta casos foram recrutados de 163 pacientes consecutivos submetidos à artrodese lombar no mesmo centro. Os pacientes foram randomizados em dois grupos de 20 pacientes: Grupo Ativo, que foi exposto a CEMP por 4 horas por dia durante 90 dias após a cirurgia e Grupo Inativo, que recebeu um dispositivo idêntico, com as mesmas instruções de uso, mas sem a capacidade de gerar CEMP. Os pacientes foram submetidos a exames de tomografia computadorizada aos 45, 90, 180 e 360 dias após a cirurgia para verificar a ocorrência de artrodese em cada nível espinhal operado. Resultados: No decorrer do estudo, dois pacientes foram excluídos de cada grupo. Não houve diferenças significativas entre os grupos com relação à idade, sexo, tabagismo ou número de níveis vertebrais incluídos na artrodese. A percentagem de consolidação dos níveis vertebrais aumentou aos 90, 180 e 360 dias em comparação com 45 dias (p < 0,001) em ambos os grupos. O Grupo Ativo teve uma chance de consolidação 276% maior nos níveis vertebrais (OR = 3,76; IC 95%: 1,39-10,20), independentemente do momento da avaliação. Os pacientes do Grupo Ativo apresentaram 16% mais consolidação do que os pacientes no grupo inativo (p = 0,018). Conclusões: A exposição pós-operatória ao CEMP após artrodese instrumentada da coluna lombar na doença degenerativa da coluna vertebral aumentou a consolidação no primeiro ano após a cirurgia.

RESUMEN Objetivo: Evaluar el efecto del campo electromagnético pulsado (CEMP) en la consolidación de la artrodesis posterolateral lumbar instrumentada en pacientes tratados quirúrgicamente por enfermedad degenerativa de la columna vertebral. Métodos: Cuarenta casos fueron reclutados de 163 pacientes consecutivos sometidos a artrodesis lumbar en el mismo centro. Los pacientes fueron asignados al azar a dos grupos de 20 pacientes: Grupo Activo, que fue expuesto a CEMP durante 4 horas al día durante 90 días después de la cirugía y Grupo Inactivo, que recibió un dispositivo idéntico, con las mismas instrucciones de uso pero sin la capacidad de generar CEMP. Los pacientes fueron sometidos a tomografía computarizada a los 45, 90, 180 y 360 días después de la cirugía para comprobar la presencia de artrodesis en cada nivel operado de la columna. Resultados: En el curso del estudio, dos pacientes fueron excluidos de cada grupo. No hubo diferencias significativas entre los grupos con respecto a la edad, el sexo, el tabaquismo o el número de niveles vertebrales incluidos en la artrodesis. El porcentaje de consolidación de los niveles vertebrales aumentó a los 90, 180 y 360 días en comparación con 45 días (p < 0,001) en ambos grupos. El Grupo Activo tenía una probabilidad 276% mayor de consolidación en los niveles vertebrales (OR = 3,76; IC del 95%: 1,39-10,20), independientemente del momento de la evaluación. Los pacientes del Grupo Activo presentaron 16% más de consolidación que los pacientes del Grupo Inactivo (p = 0,018). Conclusiones: La exposición postoperatoria a CEMP después de la artrodesis instrumentada de la columna lumbar en la enfermedad degenerativa de la columna vertebral aumentó la consolidación en el primer año después de la cirugía.

Exploratory structural assessment in craniocervical dystonia: Global and differential analyses.

INTRODUCTION: Our goal was to investigate the cortical thickness and subcortical volume in subjects with craniocervical dystonia and its subgroups. METHODS: We studied 49 subjects, 17 with cervical dystonia, 18 with blepharospasm or oromandibular dystonia, and 79 healthy controls. We performed a whole group analysis, followed by a subgroup analysis. We used Freesurfer software to measure cortical thickness, subcortical volume and to perform a primary exploratory analysis in the craniocervical dystonia group, complemented by a region of interest analysis. We also performed a secondary analysis, with data generated from Freesurfer for subgroups, corrected by false discovery rate. We then performed an exploratory generalized linear model with significant areas for the previous steps using clinical features as independent variables. RESULTS: The primary exploratory analysis demonstrated atrophy in visual processing regions in craniocervical dystonia. The secondary analysis demonstrated atrophy in motor, sensory, and visual regions in blepharospasm or oromandibular dystonia, as well as in limbic regions in cervical dystonia. Cervical dystonia patients also had greater cortical thickness than blepharospasm or oromandibular dystonia patients in frontal pole and medial orbitofrontal regions. Finally, we observed an association between precuneus, age of onset of dystonia and age at the MRI exam, in craniocervical dystonia; between motor and limbic regions and age at the exam, clinical score and time on botulinum toxin in cervical dystonia and sensory regions and age of onset and time on botulinum toxin in blepharospasm or oromandibular dystonia. CONCLUSIONS: We detected involvement of visual processing regions in craniocervical dystonia, and a pattern of involvement in cervical dystonia and blepharospasm or oromandibular dystonia, including motor, sensory and limbic areas. We also showed an association of cortical thickness atrophy and younger onset age, older age at the MRI exam, higher clinical score and an uncertain association with longer time on botulinum toxin.

Is cerebral microbleed prevalence relevant as a biomarker in amnestic mild cognitive impairment and mild Alzheimer's disease?

Introduction The search for a reliable neuroimaging biomarker in Alzheimer's disease is a matter of intense research. The presence of cerebral microbleeds seems to be a potential biomarker. However, it is not clear if the presence of microbleeds has clinical usefulness to differentiate mild Alzheimer's disease and amnestic mild cognitive impairment from normal aging. We aimed to verify if microbleed prevalence differs among three groups: mild Alzheimer's disease, amnestic mild cognitive impairment due to Alzheimer's disease, and normal controls. Moreover, we studied whether microbleeds were associated with apolipoprotein E allele ɛ4 status, cerebrospinal fluid amyloid-beta, total and phosphorylated tau protein levels, vascular factors, and cognition. Methods Twenty-eight mild Alzheimer's disease patients, 34 with amnestic mild cognitive impairment and 36 cognitively normal elderly subjects underwent: magnetic resonance imaging with a susceptibility-weighted imaging sequence on a 3T scanner, apolipoprotein E genotyping and a full neuropsychological evaluation. Only amnestic mild cognitive impairment and mild Alzheimer's disease underwent cerebrospinal fluid analysis. We compared the groups and verified if microbleeds were predicted by all other variables. Results Mild Alzheimer's disease presented a higher prevalence of apolipoprotein E allele ɛ4 in relation to amnestic mild cognitive impairment and control group. No significant differences were found between groups when considering microbleed presence. Logistic regression tests failed to find any relationship between microbleeds and the variables. We performed three different regression models using different independent variables: Model 1 - amyloid-beta, phosphorylated tau protein, total tau, apolipoprotein E allele ɛ4 status, age, and sex; Model 2 - vascular risk factors, age, and sex; Model 3 - cognitive scores sex, age, and education. Conclusion Although microbleeds might be related to the Alzheimer's disease process, their presence is not a good candidate for a neuroimaging biomarker of the disease, especially in its early phases.

Cerebellar Gray Matter Alterations in Huntington Disease: A Voxel-Based Morphometry Study.

Neuropathological and neuroimaging studies in Huntington disease (HD) have suggested a role for the cerebellum. Our goal was to perform a detailed evaluation of cerebellar morphology. We performed the Unified HD rating scale (UHDRS) and Montreal cognitive assessment (MOCA) in 26 HD patients and 26 healthy controls. We created a two-sample test to analyze cerebellar gray matter (GM) differences between groups and another to correlate GM alterations with UHDRS and MOCA, corrected for age, expanded cytosine-adenine-guanine repeats, and disease duration using the spatially unbiased atlas template (SUIT)-SPM-toolbox which preserves anatomical detailing. We found increased GM density in the anterior cerebellum compared to controls. Higher GM density in the postero-superior lobe correlated with mood symptoms. Worse motor function and better cognitive function correlated with GM changes in the posterior cerebellum (false discovery rate (FDR) correction p < 0.05 and k > 100 voxels). In this detailed study of the in vivo cerebellar morphology in HD, we observed GM changes in regions involved in sensorimotor integration, motor planning, and emotional processing, supporting cerebellar involvement in the neuropathological process of HD.

Differential Pattern of Cerebellar Atrophy in Tremor-Predominant and Akinetic/Rigidity-Predominant Parkinson's Disease.

Parkinson's disease (PD) is an akinetic-rigid disorder characterized by basal ganglia dysfunction and a possible cerebello-thalamo-cortical circuit involvement. This study aims to investigate the pattern of cerebellar involvement in PD and to assess whether it correlates with clinical parameters. MRI scans were acquired from 50 healthy controls (HC) and 63 patients; 44 were classified as tremor-predominant-PD (PDT) and 19 as akinetic/rigidity-predominant-PD (PDAR). We designed an analysis of covariance including the three groups and contrasted as follows: (1) all 63 PD vs HC, (2) PDT vs HC, (3) PDAR vs HC, and (4) PDT vs PDAR. For a precise evaluation of the cerebellum, we used the SUIT tool for voxel-based morphometry. Applying p = 0.001 and extent threshold = 20 voxels, the overall PD group vs HC showed decreased gray matter (GM) in the left lobules VI and crus I. The PDT group showed decreased cerebellar GM when compared with HC at left lobules VI, VIIb, and VIIIa; at right lobules Crus I, VIIb, and VIIIb; and vermal lobules VI and VIIIa. When compared with PDAR, PDT also showed a decrease in the left lobules VIIIa (p < 0.001). There were small clusters of both positive and negative correlation between disease duration and PDT group. The PDAR group showed no cerebellar changes. Our findings support the growing evidence of cerebellar involvement in the pathogenesis of the resting tremor.

Clinical and Imaging Evaluation of Transuncus Selective Amygdalohippocampectomy.

BACKGROUND: Various reports have described the transuncus (TU) approach as a selective route to the amygdala and hippocampus, but this approach has not yet been submitted to solid postoperative imaging analysis. The objective of this study was to evaluate the anatomy, surgical technique, postoperative imaging analysis, and outcome in a series of patients with temporal lobe epilepsy who underwent selective amigdalohippocampectomy via a TU approach. METHODS: This was a prospective study of 25 consecutive patients who underwent selective amigdalohippocampectomy through a TU approach. The temporal stem and temporal pole were evaluated through different modalities of 3-Tesla magnetic resonance imaging, including tractography of optic radiation (OR), uncinate fascicle, and inferior fronto-occipital fascicle. Visual field analysis was performed with automated perimetry. RESULTS: The mean age was 40 ± 8.21 years, and mean follow-up was 26.44 + 12.58 months. Postoperatively, 21 patients (84%) were classified as Engel I (good seizure control). Diffusion tensor imaging (DTI) data showed that 78.2% of patients had some structural damage to the temporal stem and fibers of the uncinate fascicle were identified postoperatively in only 3 patients (13.04%). The inferior fronto-occipital fascicle was identified in 18 patients (78.3%); however, subsequent DTI analysis of the remaining fibers showed them to be damaged. Integrity of the OR did not differ between these 2 groups. CONCLUSIONS: A TU approach is a feasible and efficient approach to selective amigdalohippocampectomy for surgical treatment of temporal lobe epilepsy. Postoperative DTI analysis suggests that a TU approach results in more injury to the temporal stem and its associated white matter fiber tracts than expected by previous anatomic studies; however, it was efficient in preserving OR.

Correlation between quality of life and osteolysis around lumbar pedicle screws / Relação entre qualidade de vida e osteólise em torno de parafusos pediculares lombares / Correlación entre calidad de vida y osteólisis alrededor de tornillos pediculares lumbares

ABSTRACT Objective: To evaluate whether the presence of osteolysis around the pedicle screws affects the quality of life of patients who underwent posterolateral arthrodesis of the lumbosacral spine. Methods: A retrospective study of patients undergoing lumbar posterolateral or lumbosacral arthrodesis due to spinal degenerative disease. CT scans of the operated segments were performed at intervals of 45, 90, 180, and 360 postoperatively. In these tests, the presence of a peri-implant radiolucent halo was investigated, which was considered present when greater than 1mm in the coronal section. Concurrently with the completion of CT scans, the participants completed the questionnaire Oswestry Disability Index (ODI) to assess the degree of disability of the patients. Results: A total of 38 patients were evaluated, and 14 (36.84%) of them showed some degree of osteolysis around at least one pedicle screw at the end of follow-up. Of the 242 analyzed screws, 27 (11.15%) had osteolysis in the CT coronal section, with the majority of these occurrences located at the most distal level segment of the arthrodesis. There was no correlation between the presence of the osteolysis to the quality of life of patients. The quality of life has significantly improved when comparing the preoperative results with the postoperative results at different times of application of ODI. This improvement in ODI maintains linearity over time. Conclusion: There is no correlation between the presence of peri-implant osteolysis to the quality of life of patients undergoing lumbar or posterolateral lumbosacral arthrodesis in the follow-up period up to 360 days. The quality of life in postoperative has significantly improvement when compared to the preoperative period.

RESUMO Objetivo: Avaliar se a presença de osteólise em torno dos parafusos pediculares influencia a qualidade de vida de pacientes submetidos à artrodese posterolateral da coluna lombossacral. Métodos: Estudo retrospectivo com pacientes submetidos à artrodese posterolateral lombar ou lombossacral por doença espinal degenerativa. Foram realizadas tomografias computadorizadas dos segmentos operados em intervalos de 45, 90, 180 e 360 dias de pós-operatório. Nesses exames, foi pesquisado a presença de um halo radiolucente peri-implante, que foi considerado presente quando maior que 1 mm no corte coronal. Concomitantemente à realização dos exames de TC foi aplicado o questionário Oswestry Disability Index (ODI) para avaliar o grau de incapacidade dos pacientes. Resultados: Foram avaliados 38 pacientes e 14 (36,84%) deles apresentavam algum grau de osteólise ao redor de pelo menos um parafuso pedicular ao final do seguimento. Dos 242 parafusos analisados, 27 (11,15%) apresentaram osteólise no corte coronal da TC, sendo a maioria dessas ocorrências no nível mais distal do segmento com artrodese. Não se observou relação da presença dessa osteólise com a qualidade de vida dos pacientes. A qualidade de vida tem melhora significativa quando se compara o resultado pré-operatório com os resultados pós-operatórios nos diversos momentos de aplicação do ODI. Essa melhora no ODI mantém a linearidade de melhora com o passar do tempo. Conclusão: Não há relação da presença da osteólise peri-implante com a qualidade de vida dos pacientes submetidos à artrodese lombar ou lombossacral posterolateral no período de seguimento até os 360 dias. A qualidade de vida pós-operatória tem melhora significativa quando comparada ao momento pré-operatório.

RESUMEN Objetivo: Evaluar si la presencia de osteólisis alrededor de los tornillos pediculares afecta la calidad de vida de los pacientes que fueron sometidos a artrodesis posterolateral de la columna lumbosacra. Métodos: Estudio retrospectivo de pacientes sometidos a artrodesis lumbar posterolateral o lumbosacra debido a enfermedad degenerativa de la columna vertebral. Se realizaron tomografías computarizadas de los segmentos operados en intervalos de 45, 90, 180 y 360 días después de la cirugía. En estas pruebas, fue investigada la presencia de un halo radiotransparente alrededor del implante, que se consideró presente cuando era mayor que 1 mm en corte coronal. Simultáneamente con la realización de las tomografías se aplicó el cuestionario Oswestry Disability Index (ODI) para evaluar el grado de discapacidad de los pacientes. Resultados: Se evaluaron 38 pacientes y 14 (36,84%) de ellos tenían algún grado de osteólisis alrededor de al menos un tornillo pedicular al final del seguimiento. De los 242 tornillos analizados, 27 (11,15%) tenían osteólisis en el corte coronal de la tomografía, estando la mayoría de estas ocurrencias, en el nivel más distal de la artrodesis. No hubo correlación entre la presencia de la osteólisis a la calidad de vida de los pacientes. La calidad de vida ha mejorado de manera significativa al comparar los resultados preoperatorios con los resultados postoperatorios en sus distintos momentos del ODI. Esta mejora en el ODI mantiene linealidad de mejoría con el tiempo. Conclusión: No existe correlación entre la presencia de osteólisis alrededor del implante a la calidad de vida de los pacientes sometidos a artrodesis posterolateral lumbar o lumbosacra en el período de seguimiento de hasta 360 días. La calidad de vida postoperatoria ha mejorado significativamente en comparación con el período preoperatorio.

Does Side of Onset Influence the Pattern of Cerebral Atrophy in Parkinson's Disease?

BACKGROUND: Imaging studies have revealed widespread neurodegeneration in Parkinson's disease (PD), but only a few considered the issue of asymmetrical clinical presentations. OBJECTIVE: To investigate if the side of onset influences the pattern of gray matter (GM) atrophy in PD. METHODS: Sixty patients (57.87 ± 10.27 years) diagnosed with idiopathic PD according to the U.K. Brain Bank criteria, 26 with right-sided disease onset (RDO) and 34 with left-sided disease onset (LDO), were compared to 80 healthy controls (HC) (57.1 ± 9.47 years). We acquired T1-weighted images on a 3 T scanner. Images were processed and analyzed with VBM8 (SPM8/Dartel) on Matlab R2012b platform. Statistic assessments included a two-sample test (family-wise error p < 0.05) with extent threshold of 20 voxels. RESULTS: Compared to HC, LDO patients had GM atrophy in the insula, putamen, anterior cingulate, frontotemporal cortex, and right caudate, while the RDO group showed atrophy at the anterior cingulate, insula, frontotemporal, and occipital cortex. CONCLUSION: This study revealed widespread GM atrophy in PD, predominantly in the left hemisphere, regardless of the side of onset. Future investigations should also consider handedness and side of onset to better characterize cerebral involvement and its progression in PD.

Pattern of Reduced Functional Connectivity and Structural Abnormalities in Parkinson's Disease: An Exploratory Study.

BACKGROUND: MRI brain changes in Parkinson's disease (PD) are controversial. OBJECTIVES: We aimed to describe structural and functional changes in PD. METHODS: Sixty-six patients with PD (57.94 ± 10.25 years) diagnosed according to the UK Brain Bank criteria were included. We performed a whole brain analysis using voxel-based morphometry (VBM-SPM 8 software), cortical thickness (CT) using CIVET, and resting-state fMRI using the Neuroimaging Analysis Kit software to compare patients and controls. For VBM and CT we classified subjects into three groups according to disease severity: mild PD [Hoehn and Yahr scale (HY) 1-1.5], moderate PD (HY 2-2.5), and severe PD (HY 3-5). RESULTS: We observed gray matter atrophy in the insula and inferior frontal gyrus in the moderate PD and in the insula, frontal gyrus, putamen, cingulated, and paracingulate gyri in the severe groups. In the CT analysis, in mild PD, cortical thinning was restricted to the superior temporal gyrus, gyrus rectus, and olfactory cortex; in the moderate group, the postcentral gyrus, supplementary motor area, and inferior frontal gyrus were also affected; in the severe PD, areas such as the precentral and postentral gyrus, temporal pole, fusiform, and occipital gyrus had reduced cortical thinning. We observed altered connectivity at the default mode, visual, sensorimotor, and cerebellar networks. CONCLUSION: Subjects with mild symptoms already have cortical involvement; however, further cerebral involvement seems to follow Braak's proposed mechanism. Similar regions are affected both structurally and functionally. We believe the combination of different MRI techniques may be useful in evaluating progressive brain involvement and they may eventually be used as surrogate markers of disease progression.

White Matter Microstructure in Idiopathic Craniocervical Dystonia.

BACKGROUND: Dystonias are hyperkinetic movement disorders characterized by involuntary muscle contractions resulting in abnormal torsional movements and postures. Recent neuroimaging studies in idiopathic craniocervical dystonia (CCD) have uncovered the involvement of multiple areas, including cortical ones. Our goal was to evaluate white matter (WM) microstructure in subjects with CCD using diffusion tensor imaging (DTI) analysis. METHODS: We compared 40 patients with 40 healthy controls. Patients were then divided into subgroups: cervical dystonia, blepharospasm, blepharospasm + oromandibular dystonia, blepharospasm + oromandibular dystonia + cervical dystonia, using tract-based spatial statistics. We performed a region of interest-based analysis and tractography as confirmatory tests. RESULTS: There was no significant difference in the mean fractional anisotropy (FA) and mean diffusivity (MD) between the groups in any analysis. DISCUSSION: The lack of DTI changes in CCD suggests that the WM tracts are not primarily affected.

Reproducibility of tomographic evaluation of posterolateral lumbar arthrodesis consolidation / Reprodutibilidade da avaliação tomográfica da consolidação de artrodeses posterolaterais lombares / Reproducibilidad de la evaluación tomográfica de la consolidación de artrodesis posterolaterales lumbares

To evaluate interobserver agreement of Glassman classification for posterolateral lumbar spine arthrodesis.

Avaliar a concordância interobservadores da classificação de Glassman para artrodese posterolateral da coluna lombar.

Evaluar la concordancia entre observadores de la clasificación de Glassman para artrodesis posterolateral de la columna lumbar.

Temporal stem anatomy applied to epilepsy surger / Anatomia do tronco temporal aplicada à epilepsia / Anatomía del tronco temporal aplicada a la epilepsia

This study aims to provide a brief anatomical review of the temporal stem and its white matter fiber tracts related to temporal lobe epilepsy (TLE) surgery, and review the tractography strategies to access these white matter fiber tracts using Diffusion Tensor Image (DTI) techniques. The pertinent literature about the temporal stem anatomy and function was reviewed. DTI techniques used at our neuroimaging facility were presented, as well as the tractography strategies to find the main white matter tracts coursing through the temporal stem. The knowledge of the temporal stem anatomy and the DTI techniques are important tools to analyze the white matter fiber tracts involved in TLE surgery. Such analysis is considered to be important for further evaluating the clinical role of TS and its preservation as well as to propose more selective approaches to TLE.

Este estudo tem por objetivo proporcionar uma breve revisão anatômica do tronco temporal e dos tratos de fibras de substância branca relacionados com a cirurgia da epilepsia do lobo temporal (ELT) e revisar as estratégias de tractografia para ter acesso a esses tratos de fibras de substância branca usando técnicas de imagem de tensor de difusão (ITD). A literatura pertinente sobre a anatomia do tronco temporal e sua função foi analisada. As técnicas de ITD usadas em nossas instalações de neuroimagem foram apresentadas, assim como as estratégias de tractografia para encontrar os principais tratos de substância branca que fazem trajeto através do tronco temporal. O conhecimento da anatomia do tronco temporal e as técnicas de ITD são ferramentas importantes para analisar os tratos de fibras de substância branca envol- vidos na cirurgia da ELT. Essa análise é considerada importante para melhor avaliar o papel clínico do tronco temporal e sua preservação, bem como para propor abordagens mais seletivas para a ELT.

Este estudio tiene por objetivo proporcionar una breve revisión anatómica del tronco temporal y de los tractos de fibras de sustancia blanca relacionados con la cirugía de la epilepsia del lóbulo temporal (ELT) y revisar las estrategias de tractografía para tener acceso a esos tractos de fibras de sustancia blanca usando técnicas de imagen de tensor de difusión (ITD). Fue analizada la literatura pertinente sobre la anatomía del tronco temporal y su función. Fueron presentadas las técnicas de ITD usadas en nuestras instalaciones de neuroimagen, así como las estrategias de tractografía para encontrar los principales tractos de sustancia blanca que hacen el trayecto a través del tronco temporal. El conocimiento de la anatomía del tronco temporal y las técnicas de ITD son herramientas importantes para analizar los tractos de fibras de sustancia blanca involucrados en la cirugía de ELT. Ese análisis es considerado importante para evaluar mejor el papel clínico del tronco temporal y su preservación, bien como para proponer abordajes más selectivos para la ELT.

Infratentorial gray matter atrophy and excess in primary craniocervical dystonia.

BACKGROUND: Primary craniocervical dystonia (CCD) is generally attributed to functional abnormalities in the cortico-striato-pallido-thalamocortical loops, but cerebellar pathways have also been implicated in neuroimaging studies. Hence, our purpose was to perform a volumetric evaluation of the infratentorial structures in CCD. METHODS: We compared 35 DYT1/DYT6 negative patients with CCD and 35 healthy controls. Cerebellar volume was evaluated using manual volumetry (DISPLAY software) and infratentorial volume by voxel based morphometry of gray matter (GM) segments derived from T1 weighted 3 T MRI using the SUIT tool (SPM8/Dartel). We used t-tests to compare infratentorial volumes between groups. RESULTS: Cerebellar volume was (1.14 ± 0.17) × 10(2) cm(3) for controls and (1.13 ± 0.14) × 10(2) cm(3) for patients; p = 0.74. VBM demonstrated GM increase in the left I-IV cerebellar lobules and GM decrease in the left lobules VI and Crus I and in the right lobules VI, Crus I and VIIIb. In a secondary analysis, VBM demonstrated GM increase also in the brainstem, mostly in the pons. CONCLUSION: While gray matter increase is observed in the anterior lobe of the cerebellum and in the brainstem, the atrophy is concentrated in the posterior lobe of the cerebellum, demonstrating a differential pattern of infratentorial involvement in CCD. This study shows subtle structural abnormalities of the cerebellum and brainstem in primary CCD.

Diffuse decreased gray matter in patients with idiopathic craniocervical dystonia: a voxel-based morphometry study.

BACKGROUND: Recent studies have addressed the role of structures other than the basal ganglia in the pathophysiology of craniocervical dystonia (CCD). Neuroimaging studies have attempted to identify structural abnormalities in CCD but a clear pattern of alteration has not been established. We performed whole-brain evaluation using voxel-based morphometry (VBM) to identify patterns of gray matter (GM) changes in CCD. METHODS: We compared 27 patients with CCD matched in age and gender to 54 healthy controls. VBM was used to compare GM volumes. We created a two-sample t-test corrected for subjects' age, and we tested with a level of significance of p < 0.001 and false discovery rate (FDR) correction (p < 0.05). RESULTS: Voxel-based morphometry demonstrated significant reductions of GM using p < 0.001 in the cerebellar vermis IV/V, bilaterally in the superior frontal gyrus, precuneus, anterior cingulate and paracingulate, insular cortex, lingual gyrus, and calcarine fissure; in the left hemisphere in the supplementary motor area, inferior frontal gyrus, inferior parietal gyrus, temporal pole, supramarginal gyrus, rolandic operculum, hippocampus, middle occipital gyrus, cerebellar lobules IV/V, superior, and middle temporal gyri; in the right hemisphere, the middle cingulate and precentral gyrus. Our study did not report any significant result using the FDR correction. We also detected correlations between GM volume and age, disease duration, duration of botulinum toxin treatment, and the Marsden-Fahn dystonia scale scores. CONCLUSION: We detected large clusters of GM changes chiefly in structures primarily involved in sensorimotor integration, motor planning, visuospatial function, and emotional processing.