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Gordon H Baltuch - One of the best experts on this subject based on the ideXlab platform.

Y A Chung - One of the best experts on this subject based on the ideXlab platform.

  • a new reference line for the brain ct the tuberculum sellae occipital protuberance line is parallel to the anterior Posterior Commissure line
    American Journal of Neuroradiology, 2009
    Co-Authors: Y A Chung
    Abstract:

    BACKGROUND AND PURPOSE: CT and MR imaging of the brain have diverged reference lines. Modified Talairach anterior/Posterior Commissure (ACPC) line is widely accepted as the standard for clinical brain MR imaging, while orbitomeatal line (OML) is used for CT. This study sought to determine an appropriate reference line for brain CT parallel to the ACPC line. MATERIALS AND METHODS: We measured the angles between the ACPC line and the OML, the line connecting the tuberculum sellae and the internal occipital protuberance (TS-IOP line), and the line connecting the tuberculum sellae and the external occipital protuberance (TS-EOP line) on midsagittal brain MR images of 223 patients. In addition, with the hard palate as the basis, the angles to the ACPC line in the brain MR images and new reference line on the brain CT images from the same patient were measured, and the difference between the 2 angles was calculated in 30 patients. In the same method, the angles to the OML in the brain CT images and the ACPC line on the brain MR images were measured, and their difference was calculated in 30 patients. Then the 2 difference values were compared with verification of the new reference line. RESULTS: The angles between the ACPC line and both the TS-IOP line (0.0° ± 4.0°) and the TS-EOP line (0.8° ± 3.2°) were significantly smaller than the angles between the ACPC line and the OML (–12.6° ± 4.2°; P CONCLUSIONS: TS-OP lines are nearly parallel to the ACPC line.

  • ORIGINAL RESEARCH A New Reference Line for the Brain CT: The Tuberculum Sellae-Occipital Protuberance Line is Parallel to the Anterior/Posterior Commissure Line
    2009
    Co-Authors: Y. I. Kim, Y A Chung, K. J. Ahn, B. S. Kim
    Abstract:

    BACKGROUND AND PURPOSE: CT and MR imaging of the brain have diverged reference lines. Modified Talairach anterior/Posterior Commissure (ACPC) line is widely accepted as the standard for clinical brain MR imaging, while orbitomeatal line (OML) is used for CT. This study sought to determine an appropriate reference line for brain CT parallel to the ACPC line. MATERIALS AND METHODS: We measured the angles between the ACPC line and the OML, the line connecting the tuberculum sellae and the internal occipital protuberance (TS-IOP line), and the line connecting the tuberculum sellae and the external occipital protuberance (TS-EOP line) on midsagittal brain MR images of 223 patients. In addition, with the hard palate as the basis, the angles to the ACPC line in the brain MR images and new reference line on the brain CT images from the same patient were measured, and the difference between the 2 angles was calculated in 30 patients. In the same method, the angles to the OML in the brain CT images and the ACPC line on the brain MR images were measured, and their difference was calculated in 30 patients. Then the 2 difference values were compared with verification of the new reference line. RESULTS: The angles between the ACPC line and both the TS-IOP line (0.0° 4.0°) and the TS-EOP line (0.8° 3.2°) were significantly smaller than the angles between the ACPC line and the OML (–12.6° 4.2°; P .05). In actual scanned images, the angle differences between the TS-OP (TS-IOP TS-EOP) line and the ACPC line (0.3° 4.5°) were statistically smaller than the angles between the OML and the ACPC line (–6.6° 3.9°; P .05). CONCLUSIONS: TS-OP lines are nearly parallel to the ACPC line.

Robert G Grossman - One of the best experts on this subject based on the ideXlab platform.

Jesús M. Grondona - One of the best experts on this subject based on the ideXlab platform.

  • the subcommissural organ and the development of the Posterior Commissure
    International Review of Cell and Molecular Biology, 2012
    Co-Authors: Jesús M. Grondona, P Fernandezllebrez, Carolina Hoyobecerra, Rick Visser, Maria Dolores Lopezavalos
    Abstract:

    Abstract Growing axons navigate through the developing brain by means of axon guidance molecules. Intermediate targets producing such signal molecules are used as guideposts to find distal targets. Glial, and sometimes neuronal, midline structures represent intermediate targets when axons cross the midline to reach the contralateral hemisphere. The subcommissural organ (SCO), a specialized neuroepithelium located at the dorsal midline underneath the Posterior Commissure, releases SCO-spondin, a large glycoprotein belonging to the thrombospondin superfamily that shares molecular domains with axonal pathfinding molecules. Several evidences suggest that the SCO could be involved in the development of the PC. First, both structures display a close spatiotemporal relationship. Second, certain mutants lacking an SCO present an abnormal PC. Third, some axonal guidance molecules are expressed by SCO cells. Finally, SCO cells, the Reissner's fiber (the aggregated form of SCO-spondin), or synthetic peptides from SCO-spondin affect the neurite outgrowth or neuronal aggregation in vitro.

  • The subcommissural organ and the development of the Posterior Commissure in chick embryos
    Cell and Tissue Research, 2010
    Co-Authors: Carolina Hoyo-becerra, Rick Visser, Maria Dolores López-Ávalos, Manuel Cifuentes, Pedro Fernández-llebrez, Jesús M. Grondona
    Abstract:

    The subcommissural organ (SCO) is an ependymal differentiation located in the diencephalon under the Posterior Commissure (PC). SCO-spondin, a glycoprotein released by the SCO, belongs to the thrombospondin superfamily and shares molecular domains with axonal pathfinding molecules. Several lines of evidence suggest a relationship between the SCO and the development of the PC in the chick: (1) their close location to each other, (2) their differentiation at the same developmental stage in the chick, (3) the abnormal PC found in null mutants lacking an SCO and (4) the release by the SCO of SCO-spondin. By application of DiI crystals in the PC of chick embryos, we have identified the neurons that give rise to the PC. Labelling is confined to the magnocellular nucleus of the PC (MNPC). To gain insight into the role of the SCO in PC development, coculture experiments of explants of the MNPC region (MNPCr) from embryos at embryonic day 4 (E4) with SCO explants from E4 or E13 embryos have been performed and the neurite outgrowth from the MNPCr explants has been analysed. In the case of coculture of E4 MNPCr with E4 SCO, the number of neurites growing from the MNPCr is higher at the side facing the SCO. However, when E4 MNPCr and E13 SCO are cocultured, the neurites grow mostly at the side opposite to the SCO. These data suggest that, at early stages of development, the SCO releases some attractive or permissive molecule(s) for the growing of the PC, whereas at later stages, the SCO has a repulsive effect over neurites arising from MNPCr.

  • msx1 deficient mice fail to form prosomere 1 derivatives subcommissural organ and Posterior Commissure and develop hydrocephalus
    Journal of Neuropathology and Experimental Neurology, 2004
    Co-Authors: P Fernandezllebrez, Jesús M. Grondona, Juan Perez, M F Lopezaranda, Guillermo Estivilltorrus, Pedro Llebrezzayas, Eduardo Soriano, Casto Ramos, Yvan Lallemand, Antoine Bach
    Abstract:

    : Msx1 is a regulatory gene involved in epithelio-mesenchymal interactions in limb formation and organogenesis. In the embryonic CNS, the Msx1 gene is expressed along the dorsal midline. Msx1 mutant mice have been obtained by insertion of the nlacZ gene in the Msx1 homeodomain. The most important features of homozygous mutants that we observed were the absence or malformation of the Posterior Commissure (PC) and of the subcommissural organ (SCO), the collapse of the cerebral aqueduct, and the development of hydrocephalus. Heterozygous mutants developed abnormal PC and reduced SCO, as revealed by specific antibodies against SCO secretory glycoproteins. About one third of the heterozygous mutants also showed hydrocephalus. Other defects displayed by homozygous mutants were ependymal denudation, subventricular cavitations and edema, and underdevelopment of the pineal gland and subfornical organ. Some homozygous mutants developed both SCO and PC, probably as a consequence of genetic redundancy with Msx2. However, these mutants did not show SCO-immunoreactive glycoproteins and displayed obstructive hydrocephalus. This suggests that Msx1 is necessary for the synthesis of SCO glycoproteins, which would then be required for the maintenance of an open aqueduct.

  • Pax6 and Msx1, two homeobox genes involved in the development of the subcommissural organ
    The International Journal of Developmental Biology, 2001
    Co-Authors: Guillermo Estivill-torrús, Jesús M. Grondona, Eduardo Soriano, Casto Ramos, Antoine Bach, M. F. López-aranda, Benoît Robert, Tania Vitalis, David J. Price, Pedro Fernández-llebrez
    Abstract:

    During mouse central nervous system (CNS) development, the homeobox -containing genes Pax6 and Msx1, have a spatial and temporal restricted expression in the CNS and craniofacial skeleton. Both genes are highly expressed in the glial secretory cells that forms the subcommissural organ (SCO), a circumventricular organ located at the forebrain-midbrain boundary, in the pretectal dorsal midline neuroepithelium beneath the Posterior Commissure. Pax6 (Small eye, Sey/Sey) and Msx1 (-/-) null mutants homozygous fall to develop the SCO and a normal Posterior Commissure. Pineal gland is also absent in Small eye mice. Analysis of Small eye heterozygotes demonstrated specific Pax6 defects in the developing SCO, with an important reduction in the secretory basal cell processes, in accordance with the dosage effect of Pax6. Also for Msx1, a gene-dosage effect was found since heterozygous showed a reduced (about one half) SCO. In both mutants, homozygotes and sometimes heterozygotes develop hydrocephalus. This suggests a causal relationship between the development of the SCO and of the Posterior Commissure, and between the absence of a normal SCO and the development of hydrocephalus.

Kim J. Burchiel - One of the best experts on this subject based on the ideXlab platform.

  • safety of anterior Commissure Posterior Commissure based target calculation of the subthalamic nucleus in functional stereotactic procedures
    Stereotactic and Functional Neurosurgery, 2007
    Co-Authors: Feridun Acar, Jonathan P Miller, Mehmet C Berk, Gregory J Anderson, Kim J. Burchiel
    Abstract:

    The subthalamic nucleus (STN) is a common target of functional stereotactic surgeries. High-field magnetic resonance imaging and sophisticated computer systems provide precise identification of the nucleus location in stereotactic space. However, it is unclear what additional benefit these techniques provide over traditional anterior Commissure-Posterior Commissure (AC-PC)-based standard atlas coordinate calculation methods based on the AC-PC plane. The accuracy of AC-PC-based standard atlas coordinate targeting of the STN using 1.5-tesla images compared with direct visualization of the nucleus on fused 3-tesla images was examined. A retrospective examination of stereotactic images from 20 patients (40 STN targets) who underwent deep brain stimulation for Parkinson’s disease was undertaken at our institution. Two methods were used to identify the STN stereotactic coordinates: (1) an AC-PC-based standard atlas coordinate calculation obtained by a series of measurements using 1.5-tesla images, and (2) a computer workstation calculation using fused 3-tesla and 1.5-tesla images. Euclidean distances between two sets of coordinates of the same target were calculated in three dimensions. Differences along individual X, Y, and Z axes were analyzed to determine whether there was a greater difference in one direction than in another. Data from the right and left sides were pooled to increase the sample power. The anterior-Posterior and lateral frame tilts were compared to X, Y, and Z differences to find a correlation using linear regression. Statistical analyses were performed. The accuracy of the position of the STN calculated with state-of-the-art imaging systems was not significantly better than that obtained using traditional AC-PC-based standard atlas coordinate calculation if the frame was aligned with the AC-PC plane. The mean difference was 0.45 mm, 0.72 mm, and 0.98 mm in the X, Y, and Z axes, respectively. Therefore, it is possible to effectively target the STN for stereotactic treatment of Parkinson’s disease, for instance in a situation where expensive advanced technology is unavailable.

  • ALIGNMENT CORRECTION ALGORITHM FOR TRANSFORMATION OF STEREOTACTIC ANTERIORCommissure/Posterior Commissure-BASED COORDINATES INTO FRAME COORDINATES FO R IMAGE-GUIDED FUNCTIONAL NEUROSURGERY. AUTHOR'S REPLY
    Neurosurgery, 1998
    Co-Authors: Joachim K Krauss, David E King, Robert G Grossman, R. R. Tasker, Robert J. Maciunas, Kim J. Burchiel, Patrick J. Kelly, Roy A.e. Bakay
    Abstract:

    OBJECTIVE: The goal was to describe an alignment correction algorithm for the transformation of stereotactic atlas-derived anterior Commissure/Posterior Commissure-based coordinates into frame coordinates for image-guided functional stereotactic neurosurgery. TECHNIQUE: The algorithm was developed for the calculation of targets that are referenced to the intercommissural line. It corrects for deviations of the axis of the intercommissural line in relation to the stereotactic frame (x, y, and z coordinates). The algorithm is easily implemented on a personal computer with a spreadsheet program. The calculation is fast and effective. CONCLUSION: The procedure is universally applicable for functional stereotactic neurosurgery, and it can be used with different stereotactic frames, different imaging techniques, and different workstations.

  • alignment correction algorithm for transformation of stereotactic anteriorCommissure Posterior Commissure based coordinates into frame coordinates fo r image guided functional neurosurgery author s reply
    Neurosurgery, 1998
    Co-Authors: Joachim K Krauss, David E King, Robert G Grossman, R. R. Tasker, Robert J. Maciunas, Kim J. Burchiel, Patrick J. Kelly, Roy A.e. Bakay
    Abstract:

    OBJECTIVE: The goal was to describe an alignment correction algorithm for the transformation of stereotactic atlas-derived anterior Commissure/Posterior Commissure-based coordinates into frame coordinates for image-guided functional stereotactic neurosurgery. TECHNIQUE: The algorithm was developed for the calculation of targets that are referenced to the intercommissural line. It corrects for deviations of the axis of the intercommissural line in relation to the stereotactic frame (x, y, and z coordinates). The algorithm is easily implemented on a personal computer with a spreadsheet program. The calculation is fast and effective. CONCLUSION: The procedure is universally applicable for functional stereotactic neurosurgery, and it can be used with different stereotactic frames, different imaging techniques, and different workstations.