ANA TEREZA DI LORENZO ALHO
Projetos de Pesquisa
Unidades Organizacionais
LIM/44 - Laboratório de Ressonância Magnética em Neurorradiologia, Hospital das Clínicas, Faculdade de Medicina
7 resultados
Resultados de Busca
Agora exibindo 1 - 7 de 7
- Magnetic resonance diffusion tensor imaging for the pedunculopontine nucleus: proof of concept and histological correlation(2017) ALHO, A. T. D. L.; HAMANI, C.; ALHO, E. J. L.; SILVA, R. E. da; SANTOS, G. A. B.; NEVES, R. C.; CARREIRA, L. L.; ARAUJO, C. M. M.; MAGALHAES, G.; COELHO, D. B.; ALEGRO, M. C.; MARTIN, M. G. M.; GRINBERG, L. T.; PASQUALUCCI, C. A.; HEINSEN, H.; FONOFF, E. T.; AMARO JR., E.The pedunculopontine nucleus (PPN) has been proposed as target for deep brain stimulation (DBS) in patients with postural instability and gait disorders due to its involvement in muscle tonus adjustments and control of locomotion. However, it is a deep-seated brainstem nucleus without clear imaging or electrophysiological markers. Some studies suggested that diffusion tensor imaging (DTI) may help guiding electrode placement in the PPN by showing the surrounding fiber bundles, but none have provided a direct histological correlation. We investigated DTI fractional anisotropy (FA) maps from in vivo and in situ postmortem magnetic resonance images (MRI) compared to histological evaluations for improving PPN targeting in humans. A post-mortem brain was scanned in a clinical 3T MR system in situ. Thereafter, the brain was processed with a special method ideally suited for cytoarchitectonic analyses. Also, nine volunteers had in vivo brain scanning using the same MRI protocol. Images from volunteers were compared to those obtained in the post-mortem study. FA values of the volunteers were obtained from PPN, inferior colliculus, cerebellar crossing fibers and medial lemniscus using histological data and atlas information. FA values in the PPN were significantly lower than in the surrounding white matter region and higher than in areas with predominantly gray matter. In Nissl-stained histologic sections, the PPN extended for more than 10 mm in the rostro-caudal axis being closely attached to the lateral parabrachial nucleus. Our DTI analyses and the spatial correlation with histological findings proposed a location for PPN that matched the position assigned to this nucleus in the literature. Coregistration of neuroimaging and cytoarchitectonic features can add value to help establishing functional architectonics of the PPN and facilitate neurosurgical targeting of this extended nucleus.
- Use of computational fluid dynamics for 3D fiber tract visualization on human high-thickness histological slices: histological mesh tractography(2021) ALHO, Eduardo Joaquim Lopes; FONOFF, Erich T.; ALHO, Ana Tereza Di Lorenzo; NAGY, Jozsef; HEINSEN, HelmutUnderstanding the intricate three-dimensional relationship between fiber bundles and subcortical nuclei is not a simple task. It is of paramount importance in neurosciences, especially in the field of functional neurosurgery. The current methods for in vivo and post mortem fiber tract visualization have shortcomings and contributions to the field are welcome. Several tracts were chosen to implement a new technique to help visualization of white matter tracts, using high-thickness histology and dark field images. Our study describes the use of computational fluid dynamic simulations for visualization of 3D fiber tracts segmented from dark field microscopy in high-thickness histological slices (histological mesh tractography). A post mortem human brain was MRI scanned prior to skull extraction, histologically processed and serially cut at 430 mu m thickness as previously described by our group. High-resolution dark field images were used to segment the outlines of the structures. These outlines served as basis for the construction of a 3D structured mesh, were a Finite Volume Method (FVM) simulation of water flow was performed to generate streamlines representing the geometry. The simulations were accomplished by an open source computer fluid dynamics software. The resulting simulation rendered a realistic 3D impression of the segmented anterior commissure, the left anterior limb of the internal capsule, the left uncinate fascicle, and the dentato-rubral tracts. The results are in line with clinical findings, diffusion MR imaging and anatomical dissection methods.
- Peduncolopontine DBS improves balance in progressive supranuclear palsy: Instrumental analysis(2016) SOUZA, Carolina de Oliveira; LIMA-PARDINI, Andrea Cristina de; COELHO, Daniel Boari; MACHADO, Rachael Brant; ALHO, Eduardo Joaquim Lopes; ALHO, Ana Tereza Di Lorenzo; TEIXEIRA, Luis Augusto; TEIXEIRA, Manoel Jacobsen; BARBOSA, Egberto Reis; FONOFF, Erich Talamoni
- High thickness histological sections as alternative to study the three-dimensional microscopic human sub-cortical neuroanatomy(2018) ALHO, Eduardo Joaquim Lopes; ALHO, Ana Tereza Di Lorenzo; GRINBERG, Lea; AMARO JR., Edson; SANTOS, Glaucia Aparecida Bento dos; SILVA, Rafael Emidio da; NEVES, Ricardo Caires; ALEGRO, Maryana; COELHO, Daniel Boari; TEIXEIRA, Manoel Jacobsen; FONOFF, Erich Talamoni; HEINSEN, HelmutStereotaxy is based on the precise image-guided spatial localization of targets within the human brain. Even with the recent advances in MRI technology, histological examination renders different (and complementary) information of the nervous tissue. Although several maps have been selected as a basis for correlating imaging results with the anatomical locations of sub-cortical structures, technical limitations interfere in a point-to-point correlation between imaging and anatomy due to the lack of precise correction for post-mortem tissue deformations caused by tissue fixation and processing. We present an alternative method to parcellate human brain cytoarchitectural regions, minimizing deformations caused by post-mortem and tissue-processing artifacts and enhancing segmentation by means of modified high thickness histological techniques and registration with MRI of the same specimen and into MNI space (ICBM152). A three-dimensional (3D) histological atlas of the human thalamus, basal ganglia, and basal forebrain cholinergic system is displayed. Structure's segmentations were performed in high-resolution dark-field and light-field microscopy. Bidimensional non-linear registration of the histological slices was followed by 3D registration with in situ MRI of the same subject. Manual and automated registration procedures were adopted and compared. To evaluate the quality of the registration procedures, Dice similarity coefficient and normalized weighted spectral distance were calculated and the results indicate good overlap between registered volumes and a small shape difference between them in both manual and automated registration methods. High thickness high-resolution histological slices in combination with registration to in situ MRI of the same subject provide an effective alternative method to study nuclear boundaries in the human brain, enhancing segmentation and demanding less resources and time for tissue processing than traditional methods.
conferenceObject Magnetic resonance diffusion tensor imaging for the pedunculopontine nucleus: Correlation between neuroimaging and cytoarchitectonic features(2016) ALHO, A. T. D. L.; HAMANI, C.; ALHO, E. J. L.; SILVA, R. E. da; SANTOS, G. A. B. dos; NEVES, R. C.; ARAUJO, C. M. M.; MAGALHAES, G.; GRINBERG, L. T.; HEINSEN, H.; FONOFF, E. T.; AMARO-JUNIOR, E.- The Ansa Subthalamica: A Neglected Fiber Tract(2020) ALHO, Eduardo Joaquim Lopes; ALHO, Ana Tereza Di Lorenzo; HORN, Andreas; MARTIN, Maria da Graca M.; EDLOW, Brian L.; FISCHL, Bruce; NAGY, Jozsef; FONOFF, Erich T.; HAMANI, Clement; HEINSEN, Helmut
- Pedunculopontine Nucleus Microstructure Predicts Postural and Gait Symptoms in Parkinson's Disease(2020) CRAIG, Chesney E.; JENKINSON, Ned J.; BRITTAIN, John-Stuart; GROTHE, Michel J.; ROCHESTER, Lynn; SILVERDALE, Monty; ALHO, Ana T. D. L.; ALHO, Eduardo J. L.; HOLMES, Paul S.; RAY, Nicola J.Background There is an urgent need to identify individuals at risk of postural instability and gait difficulties, and the resulting propensity for falls, in Parkinson's disease. Objectives Given known relationships between posture and gait and degeneration of the cholinergic pedunculopontine nucleus, we investigated whether metrics of pedunculopontine nucleus microstructural integrity hold independent utility for predicting future postural instability and gait difficulties and whether they could be combined with other candidate biomarkers to improve prognostication of these symptoms. Methods We used stereotactic mapping of the pedunculopontine nucleus and diffusion tensor imaging to extract baseline pedunculopontine nucleus diffusivity metrics in 147 participants with Parkinson's disease and 65 controls enrolled in the Parkinson's Progression Markers Initiative. We also recorded known candidate markers of posture and gait changes: loss of caudate dopamine and CSF beta-amyloid 1-42 levels at baseline; as well as longitudinal progression motor symptoms over 72-months. Results Survival analyses revealed that reduced dopamine in the caudate and increased axial diffusivity in the pedunculopontine nucleus incurred independent risk of postural instability and gait difficulties. Binary logistic regression and receiver operating characteristics analysis in 117 participants with complete follow-up data at 60 months revealed that only pedunculopontine nucleus microstructure provided more accurate discriminative ability for predicting future postural instability and gait difficulties than clinical and demographic variables alone. Conclusion Dopaminergic and cholinergic loss incur independent risk for future postural instability and gait difficulties, and pedunculopontine nucleus microstructure can be used to prognosticate these symptoms from early Parkinson's disease stages. (c) 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.