No abstract available.
Pyramidal Tracts*

Diffusion tensor tractorgraphy which is based on line propagation method with brute force approach is implemented and the vector correlation function is proposed in addition to the conventional fractional anisotrophy value as a criterion to select seed points. For the whole tractography, the proposed method used 41% less seed points than the conventional brute force approach for FA > or =0.3 and most of the fiber tracks in the outer region of white matter were removed. For the corticospinal tract passing through region of interest, the proposed method has produced similar results with 50% less seed points than conventional one.
Diffusion ; Pyramidal Tracts

According to the anatomical pathways of the corticobulbar tract, it is known that the responsible lesion site of central facial palsy is at the level of the midpons or the more rostral portion. In rare cases, central facial palsy is found in medullary lesions. We report two cases of medullary infarctions which presented as central facial palsy. These cases suggested that the hypothesis that part of the pathway of the facial corticobulbar fibers descend ipsilaterally to the lower medulla before decussating and ascending contralaterally to the facial nucleus.
Facial Paralysis* ; Infarction* ; Pyramidal Tracts

No abstract available.
Brain ; Muscle Spasticity ; Paraparesis, Spastic ; Pyramidal Tracts

PURPOSE: Diffusion tensor imaging (DTI) data must be analyzed by an analyzer after data processing. Hence, the analyzed data of DTI might depend on the analyzer, making it a major limitation. This paper reviewed previous DTI studies reporting the repeatability and reproducibility of data from the corticospinal tract (CST), one of the most actively researched neural tracts on this topic. MATERIALS AND METHODS: Relevant studies published between January 1990 and December 2018 were identified by searching PubMed, Google Scholar, and MEDLINE electronic databases using the following keywords: DTI, diffusion tensor tractography, reliability, repeatability, reproducibility, and CST. As a result, 15 studies were selected. RESULTS: Measurements of the CSTs using region of interest methods on 2-dimensional DTI images generally showed excellent repeatability and reproducibility of more than 0.8 but high variability (0.29 to 1.00) between studies. In contrast, measurements of the CST using the 3-dimensional DTT method not only revealed excellent repeatability and reproducibility of more than 0.9 but also low variability (repeatability, 0.88 to 1.00; reproducibility, 0.82 to 0.99) between studies. CONCLUSION: Both 2-dimensional DTI and 3-dimensional DTT methods appeared to be reliable for measuring the CST but the 3-dimensional DTT method appeared to be more reliable.
Diffusion Tensor Imaging ; Diffusion ; Methods ; Pyramidal Tracts

No abstract available.
Diffusion ; Leukoencephalopathies ; Pyramidal Tracts ; Sepsis ; Sepsis-Associated Encephalopathy

Opalski syndrome is a rare lateral medullary infarction variant presenting with ipsilateral motor deficits known to be caused by involvement of the post-decussating pyramidal tract. Here, we report two rare cases of Opalski syndrome presenting as ipsilateral sensorimotor deficits in cerebral infarction.
Cerebral Infarction ; Infarction ; Lateral Medullary Syndrome ; Pyramidal Tracts

We report the clinical usefulness of elucidating the state of the corticospinal tract (CST) by the use of diffusion tensor image tractography (DTT) in hemiparetic stroke patients. DTT was performed using 1.5 T magnetic resonance imaging. DTT demonstrated that the CST of the affected hemisphere was preserved in the medial portion of the hematoma in patient 1, but was interrupted by a hematoma in patient 2. DTT seems to be useful for elucidating the status of the CST in hemiparetic stroke patients.
Diffusion ; Hematoma ; Humans ; Magnetic Resonance Imaging ; Pyramidal Tracts ; Stroke

Diffusion tensor imaging (DTI) allows to isolate the corticospinal tract (CST) area from adjacent structures. Using DTI, we investigated the characteristics of the CST areas according to the pontine level in the normal human brain. We recruited 33 healthy subjects and DTIs were acquired using a sensitivity-encoding head coil on a 1.5-T Philips Gyroscan Intera. We measured the size and fractional anisotropy (FA) value of the CST area at the upper, middle, and lower pons. The size of the CST area in the lower pons was smaller than those of the mid-pons and upper pons, and the size of the CST area in the mid-pons was smallerthan that of the upper pons (p<0.05). FA values of the lower pons were larger than those of the mid-pons and upper pons, and the FA value of the mid-pons was also larger than that of the upper pons (p<0.05). In summary, we found a smaller size and higher FA value of the CST area from rostral to caudal direction in the pons. These results suggest a more compact neural structure of CST areas from rostral to caudal direction in the pons.
Adult ; Brain/*anatomy & histology ; Diffusion Tensor Imaging ; Female ; Humans ; Male ; Middle Aged ; Pyramidal Tracts/*anatomy & histology

Intracranial gliomas were found more commonly in childhood(70 to 80%) than in adulthood(40 to 45%). The common infratentorial tumors in children were cerebellar astrocytoma(26.9%), medulloblastoma(18.5%) and brain stem glioma(10.5%). Brain stem gliomas were infiltrating type of tumor and frequently involved the pons and medulla. An almost pathognomic syndrome of the brain stem gliomas consists in the presences of multiple bilateral cranial nerve abnormalities in combination with involving signs of pyramidal tract and cerebro-dentato-rubro-thalamic tract in the absence signs of increased ICP, especially in the early stage. These tumors take grave course because of clinical malignancy and lack of definite therapy. Once diagnosed, radiation therapy was at best palliative treatment. Sometimes surgical therapy could be attempted to find out curable cysts. We have been experienced in a case of brain stem glioma recently that was confirmed with an autopsy;astrocytoma grade II to III, microscopically.
Brain Stem* ; Brain* ; Child ; Cranial Nerves ; Glioma* ; Humans ; Infratentorial Neoplasms ; Palliative Care ; Pons ; Pyramidal Tracts