Hendrik Juenger1, Inga K Koerte2, Marc Muehlmann3, Michael Mayinger4, Volker Mall5, Ingeborg Krägeloh-Mann6, Martha E Shenton7, Steffen Berweck8, Martin Staudt9, Florian Heinen10. 1. Department of Pediatrics, Klinikum rechts der Isar, Technical University Munich, Koelner Platz 1, 80804 Munich, Germany; Department of Pediatric Neurology and Developmental Medicine, University Children's Hospital, Tübingen, Germany. Electronic address: hendrik.juenger@lrz.tu-muenchen.de. 2. Psychiatry Neuroimaging Laboratory, Department of Radiology and Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, USA; Institute for Clinical Radiology, Ludwig-Maximilian-University, Munich, Germany; Department of Child and Adolescent Psychiatry, Psychosomatic and Psychotherapy, Ludwig-Maximilian-University, Munich, Germany. 3. Institute for Clinical Radiology, Ludwig-Maximilian-University, Munich, Germany; Psychiatry Neuroimaging Laboratory, Department of Radiology and Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, USA; Department of Child and Adolescent Psychiatry, Psychosomatic and Psychotherapy, Ludwig-Maximilian-University, Munich, Germany. 4. Institute for Clinical Radiology, Ludwig-Maximilian-University, Munich, Germany; Psychiatry Neuroimaging Laboratory, Department of Radiology and Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, USA. 5. Social Pediatrics and Developmental Medicine, Klinikum rechts der Isar, Technical University Munich, Koelner Platz 1, 80804 Munich, Germany. 6. Department of Pediatric Neurology and Developmental Medicine, University Children's Hospital, Tübingen, Germany. 7. Psychiatry Neuroimaging Laboratory, Department of Radiology and Psychiatry, Brigham and Women's Hospital, Harvard Medical School, Boston, USA; Veterans Affairs (VA) Boston Healthcare System, Brockton, MA, USA. 8. Clinic for Neuropediatrics and Neurorehabilitation, Epilepsy Center for Children and Adolescents, Krankenhausstr. 20, 83569 Vogtareuth, Germany. 9. Department of Pediatric Neurology and Developmental Medicine, University Children's Hospital, Tübingen, Germany; Clinic for Neuropediatrics and Neurorehabilitation, Epilepsy Center for Children and Adolescents, Krankenhausstr. 20, 83569 Vogtareuth, Germany. 10. Department of Pediatric Neurology and Developmental Medicine, Hauner Children's Hospital, Ludwig-Maximilian-University, Munich, Germany; German Center for Vertigo and Balance Disorders, University of Munich, Munich, Germany.
Abstract
BACKGROUND: Early unilateral brain lesions can lead to different types of corticospinal (re-)organization of motor networks. In one group of patients, the contralesional hemisphere exerts motor control not only over the contralateral non-paretic hand but also over the (ipsilateral) paretic hand, as the primary motor cortex is (re-)organized in the contralesional hemisphere. Another group of patients with early unilateral lesions shows "normal" contralateral motor projections starting in the lesioned hemisphere. AIM: We investigated how these different patterns of cortical (re-)organization affect interhemispheric transcallosal connectivity in patients with congenital hemiparesis. METHOD: Eight patients with ipsilateral motor projections (group IPSI) versus 7 patients with contralateral motor projections (group CONTRA) underwent magnetic resonance diffusion tensor imaging (DTI). The corpus callosum (CC) was subdivided in 5 areas (I-V) in the mid-sagittal slice and volumetric information. The following diffusion parameters were calculated: fractional anisotropy (FA), trace, radial diffusivity (RD), and axial diffusivity (AD). RESULTS: DTI revealed significantly lower FA, increased trace and RD for group IPSI compared to group CONTRA in area III of the corpus callosum, where transcallosal motor fibers cross the CC. In the directly neighboring area IV, where transcallosal somatosensory fibers cross the CC, no differences were found for these DTI parameters between IPSI and CONTRA. Volume of callosal subsections showed significant differences for area II (connecting premotor cortices) and III, where group IPSI had lower volume. INTERPRETATION: The results of this study demonstrate that the callosal microstructure in patients with congenital hemiparesis reflects the type of cortical (re-)organization. Early lesions disrupting corticospinal motor projections to the paretic hand consecutively affect the development or maintenance of transcallosal motor fibers.
BACKGROUND: Early unilateral brain lesions can lead to different types of corticospinal (re-)organization of motor networks. In one group of patients, the contralesional hemisphere exerts motor control not only over the contralateral non-paretic hand but also over the (ipsilateral) paretic hand, as the primary motor cortex is (re-)organized in the contralesional hemisphere. Another group of patients with early unilateral lesions shows "normal" contralateral motor projections starting in the lesioned hemisphere. AIM: We investigated how these different patterns of cortical (re-)organization affect interhemispheric transcallosal connectivity in patients with congenital hemiparesis. METHOD: Eight patients with ipsilateral motor projections (group IPSI) versus 7 patients with contralateral motor projections (group CONTRA) underwent magnetic resonance diffusion tensor imaging (DTI). The corpus callosum (CC) was subdivided in 5 areas (I-V) in the mid-sagittal slice and volumetric information. The following diffusion parameters were calculated: fractional anisotropy (FA), trace, radial diffusivity (RD), and axial diffusivity (AD). RESULTS: DTI revealed significantly lower FA, increased trace and RD for group IPSI compared to group CONTRA in area III of the corpus callosum, where transcallosal motor fibers cross the CC. In the directly neighboring area IV, where transcallosal somatosensory fibers cross the CC, no differences were found for these DTI parameters between IPSI and CONTRA. Volume of callosal subsections showed significant differences for area II (connecting premotor cortices) and III, where group IPSI had lower volume. INTERPRETATION: The results of this study demonstrate that the callosal microstructure in patients with congenital hemiparesis reflects the type of cortical (re-)organization. Early lesions disrupting corticospinal motor projections to the paretic hand consecutively affect the development or maintenance of transcallosal motor fibers.
Authors: Julia Pavaine; Julia M Young; Benjamin R Morgan; Manohar Shroff; Charles Raybaud; Margot J Taylor Journal: Neuroradiology Date: 2015-12-21 Impact factor: 2.804