Journal of Yeungnam Medical Science

Sang Ho Ahn

3 Articles

Transcallosal Fibers from the Corticospinal Tract in Adults with Brain Injury: Sung Ho Jang, Sang Ho Ahn, Yun Woo Cho; Yeungnam Univ J Med. 2007;24(2 Suppl):S424-429. Published online December 31, 2007; DOI: https://doi.org/10.12701/yujm.2007.24.2S.S424

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Background
：Diffusion tensor image tractography (DTT) can visualize white matter tracts and provide us with a powerful vehicle for investigating the neuralpathway at the subcortical level. Using DTT, we attempted to demonstrate abnormal transcallosal fibers from the corticospinal tract in patients with brain injury. Materials and Methods：Four adults with brain injury (2 patients: stroke, 1 patient: brain tumor with hemorrhage, 1 patient: diffuse axonal injury) and 14 normal control subjects were enrolled in this study. DTT was performed using 1.5-T with a Synergy-L Sensitivity Encoding head coil. Three-dimensional reconstructions of the fiber tracts were obtained with FA<3.0, and an angle change >45o as termination criteria.
Results
：Transcallosal fibers were observed in two of 14 normal controls, and ascended to the cortex leaving the corpus callosum. All four patients showed transcallosal fibers which stemmed from the corticospinal tract of the unaffected hemisphere, and descended to or around the lesion at the subcortical area.
Conclusion
：It seems that transcallosal fibers which arise from the corticospinal tract of the unaffected hemisphere may act as pathological fibers for motor deficit compensation.

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Usefulness of DTI-based three dimensional corticospinal tractography in children with hemiplegic cerebral palsy
Ji Hyun Yeo, Su Min Son, Eun Sil Lee, Han Ku Moon
Korean Journal of Pediatrics.2009; 52(1): 99. CrossRef

Evidence of Cortical Reorganization in a Monoparetic Patient with Cerebral Palsy Detected by Combined Functional MRI and TMS.: Yong Hyun Kwon, Sung Ho Jang, Mi Young Lee, Woo Mok Byun, Yoon Woo Cho, Sang Ho Ahn; Yeungnam Univ J Med. 2005;22(1):96-103. Published online June 30, 2005; DOI: https://doi.org/10.12701/yujm.2005.22.1.96

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Abstract PDF: The motor recovery mechanism of a 21-year-old male monoparetic patient with cerebral palsy, who had complained of a mild weakness on his right hand since infancy, was examined using functional Magnetic Resonance Imaging (fMRI) and Transcranial Magnetic Stimulation (TMS). The patient showed mild motor impairment on the right hand. MRI located the main lesion on the left precentral knob of the brain. fMRI was performed on this patient as well as 8 control subjects using the Blood Oxygen Level Dependent technique at 1.5 T with a standard head coil. The motor activation task consisted of finger flexion- extension exercises at 1 Hz cycles. TMS was carried out using a round coil. The anterior portion of the coil was applied tangentially to the scalp at a 1.0 cm separation. Magnetic stimulation was carried out with the maximal output. The Motor Evoked Potentials (MEPs) from both Abductor Pollicis Brevis muscles (APB) were obtained simultaneously. fMRI revealed that the unaffected (right) primary sensori-motor cortex (SM1), which was centered on precentral knob, was activated by the hand movements of the control subjects as well as by the unaffected (left) hand movements of the patient. However, the affected (right) hand movements of the patient activated the medial portion of the injured precentral knob of the left SM1. The optimal scalp site for the affected (right) APB was located at 1 cm medial to that of the unaffected (left) APB. When the optimal scalp site was stimulated, the MEP characteristics from the affected (right) APB showed a delayed latency, lower amplitude, and a distorted figure compared with that of the unaffected (left) APB. Therefore, the motor function of the affected (right) hand was shown to be reorganized in the medial portion of the injured precentral knob.

Microsurgical DREZotomy for treatment of intractable central pain in patient with spinal cord injury.: Zee Ihn Lee, Seong Ho Kim, Sang Ho Ahn, Sung Ho Jang; Yeungnam Univ J Med. 2002;19(1):49-54. Published online June 30, 2002; DOI: https://doi.org/10.12701/yujm.2002.19.1.49

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Abstract PDF: The central pain in patient with spinal cord injury is a common and disabling sequelae. The microsurgical DREZ(Dorsal Root Entry Zone)otomy is a surgical procedure effective in the treatment of intractable pain and spasticity in spinal cord injured patients. It consists of a microsurgical lesions performed in the ventrolateral region of the dorsal root entry zone at the selected levels. This report presents one case with incomplete paraplegia patient, who had chronic central neuropathic pain ineffective to many conservative treatments in bilateral T10 and right T11 segments and both lower extremities, is relieved from the pain after microsurgical DREZotomy. In conclusion, microsurgical DREZotomy is one method of effective treatments for spinal cord injured patients with intractable central neuropathic pain.

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