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Intraoperative Optical Guidance for Neurosurgery
Published in Yu Chen, Babak Kateb, Neurophotonics and Brain Mapping, 2017
Chia-Pin Liang, Cha-Min Tang, Yu Chen
The images of the human basal ganglia ex vivo illustrate the potential for neurosurgical guidance. Figure 21.8 shows a camera image of human brain tissue and the full-track reconstructed OCT image. In the camera image of brain tissue, note the white appearance of fiber tracts surrounding the GM nuclei and the striation of white fiber bundles within the PUT. The reconstructed OCT track was obtained by pushing the probe from right to left 2 mm below and parallel to the surface of the brain slice. This figure illustrates the high degree of contrast between GM and WM generated by OCT. The transition between the thin white fiber capsule, the GM PUT, and the lamina to the globus pallidus externa (GPe) can be clearly identified. These OCT-detectable structures are useful anatomic landmarks that can be used in stereotactic surgery (Jafri et al., 2005, 2009; Jeon et al., 2006). The structures identified in this passage include extreme capsule (ex), claustrum (Cl), external capsule (ec), PUT, and lateral medullary lamina (lml). The WM typically has much higher intensity with shallower penetration depth. Also, the characteristic WM striations in the PUT display high contrast and can be easily identified. Because the needle was inserted 2 mm below and parallel to the surface of the brain slice, the number and the size of the fiber tracts in the camera image are different from the fiber tracks in OCT image. Reconstruction of the full-track OCT image allows better identification of the probe location. This information can assist in the guidance of therapeutic tools to deep brain targets with micrometer precision.
The impact of phonological versus semantic repetition training on generalisation in chronic stroke aphasia reflects differences in dorsal pathway connectivity
Published in Neuropsychological Rehabilitation, 2018
Rachel Holland, Sasha L. Johns, Anna M. Woollams
Although independent, the ventral and dorsal streams are highly interactive. Rolheiser, Stamatakis, and Tyler (2011) considered 24 chronic stroke patients’ performance across 10 tests involving key aspects of language production and comprehension and how this related to the results of diffusion weighted imaging. Phonological processing was found to load most heavily on the arcuate fascicle, implicated in the dorsal stream (Hickok & Poeppel, 2007). Conversely, semantic tasks were found to load on the extreme capsule, which was implicated in the ventral stream (Hickok & Poeppel, 2007). Importantly, whole-brain correlations showed that only performance on tasks loading strongly on either phonology or semantics fitted into this dual-stream model, whereas complex linguistic functions of syntax and morphology required integrity of both pathways (Rolheiser et al., 2011).
3.0 Tesla MRI scanner evaluation of supratentorial major white matter tracts and central core anatomical structures of postmortem human brain hemispheres fixed by Klingler method
Published in British Journal of Neurosurgery, 2021
Murat Atar, Ceren Kizmazoglu, Ismail Kaya, Nevin Aydin, Ufuk Corumlu, Gulden Sozer, Hasan Emre Aydin, Orhan Kalemci, Nuri Karabay, Nurullah Yuceer
Figure 1 shows the axial image obtained with the 3.0 Tesla MRI scanner shows the insular structure and basal nuclei in the left hemisphere. The distinction between claustrum, extreme capsule, and external capsule is very clear. In addition, the lateral and medial parts of the globus pallidus can be clearly distinguished on the other hand the white matter tracts in the T2 axial left hemisphere image obtained with 3.0 Tesla MRI scanner in a healthy person cannot be clearly identified.