• Title/Summary/Keyword: tensor

Search Result 1,319, Processing Time 0.029 seconds

The Effect of Tensor Fasciea Latae Length on the Rotation of Pelvic during One Leg Stance (대퇴근막장근의 길이가 한발서기 시 골반의 회전에 미치는 영향)

  • Kim, Byoung-Kon;Son, Jung-Hee
    • The Journal of Korean Academy of Orthopedic Manual Physical Therapy
    • /
    • v.15 no.2
    • /
    • pp.63-68
    • /
    • 2009
  • Purpose : The purpose of this study was to investigate the effect of tensor fasciae latae length on the rotation of pelvis during one leg stance. Methods : 41 healthy adults participated in this study. The movement of the pelvis and trunk was measured using 3-dimensional motion analyzer, during one leg stance. The movement of the pelvis and trunk was collected lateral shift, rotation, side bending, and flexion-extension. Tensor fasciae latae length of subjects was measured in sidelying positon with neutral position of hip joint and flexion $90^{\circ}$ of knee. Also, the range of motion of hip exteral and interal rotaion were measured in prone position wih lexion $90^{\circ}$ of knee. The subjects were separated 2 groups that more pelvic rotation group(n=15) and less pelvic rotation group(n=15) according to the degree of pelvic rotation. Results : The more pelvic rotation group was showed significantly higher in the ROM of hip external rotation than less pelvic rotation group(p<0.05). The difference of tensor fasciae latae length not showed significant difference between groups. During one leg stance, The movement of the shifting and flexion-extension of trunk and pelvis were not showed significant difference. But the side bending and the rotation of pelvis and trunk showed significant difference between groups. Conclusion : The difference of tensor fasciae latae length not showed significantly in more pelvic rotation group and less pelvic rotation group. But, this study suggests that the pelvis instability brings the instability of the trunk during one leg stance.

  • PDF

Significance of Preoperative Nerve Reconstruction Using Diffusion Tensor Imaging Tractography for Facial Nerve Protection in Vestibular Schwannoma

  • Yuanlong Zhang;Hongliang Ge;Mingxia Xu;Wenzhong Mei
    • Journal of Korean Neurosurgical Society
    • /
    • v.66 no.2
    • /
    • pp.183-189
    • /
    • 2023
  • Objective : The facial nerve trace on the ipsilateral side of the vestibular schwannoma was reconstructed by diffusion tensor imaging tractography to identify the adjacent relationship between the facial nerve and the tumor, and to improve the level of intraoperative facial nerve protection. Methods : The clinical data of 30 cases of unilateral vestibular schwannoma who underwent tumor resection via retrosigmoid approach were collected between January 2019 and December 2020. All cases underwent magnetic resonance imaging examination before operation. Diffusion tensor imaging and anatomical images were used to reconstruct the facial nerve track of the affected side, so as to predict the course of the nerve and its adjacent relationship with the tumor, to compare the actual trace of the facial nerve during operation, verify the degree of coincidence, and evaluate the nerve function (House-Brackmann grade) after surgery. Results : The facial nerve of 27 out of 30 cases could be displayed by diffusion tensor imaging tractography, and the tracking rate was 90% (27/30). The intraoperative locations of facial nerve shown in 25 cases were consistent with the preoperative reconstruction results. The coincidence rate was 92.6% (25/27). The facial nerves were located on the anterior middle part of the tumor in 14 cases, anterior upper part in eight cases, anterior lower part in seven cases, and superior polar in one case. Intraoperative facial nerve anatomy was preserved in 30 cases. Among the 30 patients, total resection was performed in 28 cases and subtotal resection in two cases. The facial nerve function was evaluated 2 weeks after operation, and the results showed grade I in 12 cases, grade II in 16 cases and grade III in two cases. Conclusion : Preoperative diffusion tensor imaging tractography can clearly show the trajectory and adjacent position of the facial nerve on the side of vestibular schwannoma, which is beneficial to accurately identify and effectively protect the facial nerve during the operation, and is worthy of clinical application and promotion.

Multi-slice Multi-echo Pulsed-gradient Spin-echo (MePGSE) Sequence for Diffusion Tensor Imaging MRI: A Preliminary Result (일회 영상으로 확산텐서 자기공명영상을 얻을 수 있는 다편-다에코 펄스 경사자장 스핀에코(MePGSE) 시퀀스의 초기 결과)

  • Jahng, Geon-Ho;Pickup, Stephen
    • Progress in Medical Physics
    • /
    • v.18 no.2
    • /
    • pp.65-72
    • /
    • 2007
  • An echo planar imaging (EPI)-based spin-echo sequence Is often used to obtain diffusion tensor imaging (DTI) data on most of the clinical MRI systems, However, this sequence is confounded with the susceptibility artifacts, especially on the temporal lobe in the human brain. Therefore, the objective of this study was to design a pulse sequence that relatively immunizes the susceptibility artifacts, but can map diffusion tensor components in a single-shot mode. A multi-slice multi-echo pulsed-gradient spin-echo (MePGSE) sequence with eight echoes wasdeveloped with selective refocusing pulses for all slices to map the full tensor. The first seven echoes in the train were diffusion-weighted allowing for the observation of diffusion in several different directions in a single experiment and the last echo was for crusher of the residual magnetization. All components of diffusion tensor were measured by a single shot experiment. The sequence was applied in diffusive phantoms. The preliminary experimental verification of the sequence was illustrated by measuring the apparent diffusion coefficient (ADC) for tap water and by measuring diffusion tensor components for watermelon. The ADC values in the series of the water phantom were reliable. The MePGSE sequence, therefore, may be useful in human brain studies.

  • PDF

CONFORMAL CHANGE OF THE TENSOR Sλμν IN 5-DIMENSIONAL g-UFT

  • Cho, Chung Hyun
    • Korean Journal of Mathematics
    • /
    • v.6 no.2
    • /
    • pp.213-220
    • /
    • 1998
  • We investigate change of the torsion tensor induced by the conformal change in 5-dimensional $g$-unified field theory. These topics will be studied for the second class in 5-dimensional case.

  • PDF

KAEHLER SUBMANIFOLDS WITH RS=0 IN A COMPLEX PROJECTIVE SPACE

  • Hyun, Jong-Ik
    • Communications of the Korean Mathematical Society
    • /
    • v.12 no.3
    • /
    • pp.685-690
    • /
    • 1997
  • Our study focuses on the condition under which a subspace of complex projective space can become an Einstein space. We prove that a subspace becomes an Einstein space if it's codimension is less than n-1 and its curvature tensor and Ricci tensor satisfies Ryan's condition.

  • PDF

A SOLUTION OF EINSTEIN'S UNIFIED FIELD EQUATIONS

  • Lee, Jong-Woo;Chung, Kyung-Tae
    • Communications of the Korean Mathematical Society
    • /
    • v.11 no.4
    • /
    • pp.1047-1053
    • /
    • 1996
  • In this paper, we obtain a solution of Einstein's unified field equations on a generalized n-dimensional Riemannian manifold $X_n$.

  • PDF