• Title/Summary/Keyword: Oblique view

Search Result 86, Processing Time 0.045 seconds

Accurate Localization of Metal Electrodes Using Magnetic Resonance Imaging (자기공명영상을 이용한 금속전극의 정확한 위치 결정)

  • Joe, Eun-Hae;Ghim, Min-Oh;Ha, Yoon;Kim, Dong-Hyun
    • Investigative Magnetic Resonance Imaging
    • /
    • v.15 no.1
    • /
    • pp.11-21
    • /
    • 2011
  • Purpose : Localization using MRI is difficult due to susceptibility induced artifacts caused by metal electrodes. Here we took an advantage of the B0 pattern induced by the metal electrodes by using an oblique-view imaging method. Materials and Methods : Metal electrode models with various diameters and susceptibilities were simulated to understand the aspect of field distortion. We set localization criteria for a turbo spin-echo (TSE) sequence usingconventional ($90^{\circ}$ view) and $45^{\circ}$ oblique-view imaging method through simulation of images with various resolutions and validated the criteria usingphantom images acquired by a 3.0T clinical MRI system. For a gradient-refocused echo (GRE) sequence, which is relatively more sensitive to field inhomogeneity, we used phase images to find the center of electrode. Results : There was least field inhomogeneity along the $45^{\circ}$ line that penetrated the center of the electrode. Therefore, our criteria for the TSE sequence with $45^{\circ}$ oblique-view was coincided regardless of susceptibility. And with $45^{\circ}$ oblique-view angle images, pixel shifts were bidirectional so we can detect the location of electrodes even in low resolution. For the GRE sequence, the $45^{\circ}$ oblique-view anglemethod madethe lines where field polarity changes become coincident to the Cartesian grid so the localization of the center coordinates was more facilitated. Conclusion : We suggested the method for accurate localization of electrode using $45^{\circ}$ oblique-view angle imaging. It is expected to be a novelmethodto monitoring an electrophysiological brain study and brain neurosurgery.

A Study on the Thyroid Scan Images by Different Radionuclides ($^{99m}Tc$ pertechnetate and $^{131}I$) and Multiple Views (사용핵종(使用核種) 및 주사방향(走査方向)에 따른 갑상선주사상(甲狀腺走査像)의 차이(差異)에 관한 연구(硏究))

  • Whang, Il-Yong;Chung, Soon-Il;Kim, Dong-Soo
    • The Korean Journal of Nuclear Medicine
    • /
    • v.20 no.1
    • /
    • pp.53-58
    • /
    • 1986
  • Thyroid scans using $Na^{131}I\;and\;^{99m}TcO_4^-$ in two (anterior and anterior oblique) projections were done simultaneously in 50 patients with single palpable nodule and in euthyroid state(nodular nontoxic goiter) and 20 normal subjects to evaluate the imaging ability of each radionuclide and the necessity of oblique view. In detection of a nodule as a cold or cool area, $^{99m}TcO_4^-$ was slightly superior to $^{131}I$(82 % to 78% with anterior view alone, 92% to 84% when oblique view is added in detectability), with addition of an oblique view, 5 more cold or cool area in $^{99m}Tc$ scan and 3 more $^{131}I$ scan were detected. In normal subjects $^{99m}TcO_4^-$ scan was significantly superior to $^{131}I$ scan(90% to 70%) in getting normal pattern of tracer uptake in the glands. For routine imaging study of the thyroid, $^{99m}Tc$ pertechnetate scan with multiple projection is considered to be a preferable method.

  • PDF

Platform Calibration of an Aerial Multi-View Camera System (항공용 다각사진 카메라 시스템의 플랫폼 캘리브레이션)

  • Lee, Chang-No;Kim, Chang-Jae;Seo, Sang-Il
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.28 no.3
    • /
    • pp.369-375
    • /
    • 2010
  • Since multi-view images can be utilized for 3D visualization and surveying as well, a system calibration is an essential procedure. The cameras in the system are mounted to the holder and their locations and attitudes are relatively fixed. Therefore, the locations and the attitudes of the perspective centers of the four oblique looking cameras can be calculated using the location and attitude of the nadir looking camera and the boresight values between the cameras. In this regard, this research is focusing on the analysis of the relative location and attitude between the nadir and oblique looking cameras based on the results of the exterior orientation parameters after the aerial triangulation of the real multiview images. We acquired high standard deviations of the relative locations between the nadir and oblique cameras. Standard deviations of the relative attitudes between the cameras were low when only the exterior orientations of the oblique looking cameras were allowed to be adjusted. Moreover, low standard deviations of the relative attitudes came when we considered not all the exterior orientations of the cameras but the attitudes of them only.

Comparison of the Surface Dose of the Thyroid according to AP versus PA Positioning in Cervical Spine Oblique View (경추 사방향 검사에서 전후면과 후전면 자세에 따른 갑상선 표면선량 비교)

  • Park, Jeong-Ho;Yang, Sung-Gyu;Kim, Ki-Jeong;Joo, Young-Cheol;Hong, Dong-Hee;Lim, Woo-Taek
    • Journal of radiological science and technology
    • /
    • v.40 no.4
    • /
    • pp.543-548
    • /
    • 2017
  • The aim of this study was to evaluate anteroposterior oblique(RPO, LPO) and posteroanterior oblique(LAO, RAO) projections of the cervical spine, at various kVp and mA s increments, in order to compare thyroid surface dose. Using Rando phantom, dosimeter was attached to the Cervical spine 4~5 to measure the surface dose in the same thyroid position. As a result, the surface dose was $595.08{\pm}215.01{\mu}Gy$ for anteroposterior oblique(RPO, LPO) projections and $64.21{\pm}33.49{\mu}Gy$ for posteroanterior oblique(LAO, RAO) projections by changing kVp increment. The surface dose was $445.20{\pm}230.90{\mu}Gy$ for anteroposterior oblique(RPO, LPO) projections and $44.51{\pm}22.77{\mu}Gy$ for posteroanterior oblique(LAO, RAO) projections by changing mAs increment. The posteroanterior oblique method could reduce about 90% the surface dose than the anteroposterior oblique method. There were statistically significant differences among the examinations(p<0.001). Change the direction of position to reduce the surface dose at oblique projection of cervical spine. Therefore, we consider posteroanterior oblique projections than anteroposterior oblique projections of cervical spine examination in other to reduce patient surface dose.

Research on The Utility of Acquisition of Oblique Views of Bilateral Orbit During the Dacryoscintigraphy (눈물길 조영검사 시 양측 안 와 사위 상 획득의 유용성에 대한 연구)

  • Park, Jwa-Woo;Lee, Bum-Hee;Park, Seung-Hwan;Park, Su-Young;Jung, Chan-Wook;Ryu, Hyung-Gi;Kim, Ho-Shin
    • The Korean Journal of Nuclear Medicine Technology
    • /
    • v.18 no.1
    • /
    • pp.76-81
    • /
    • 2014
  • Purpose: Diversity and the lachrymal duct deformities and the passage inside the nasal cavity except for anterior image such as epiphora happens during the test were able to express more precisely during the dacryoscintigraphy. Also, we thought about the necessity of a method to classify the passage into the naso-lachrymal duct from epiphora. Therefore, we are to find the validity of the method to obtain both oblique views except for anterior views. Materials and Methods: The targets of this research are 78 patients with epiphora due to the blockage at the lachrymal duct from January 2013 to August 2013. Average age was $56.96{\pm}13.36$. By using a micropipette, we dropped 1-2 drops of $^{99m}TcO4^-$ of 3.7 MBq (0.1 mCi) with $10{\mu}L$ of each drop into the inferior conjunctival fold, then we performed dynamic check for 20 minutes with 20 frames of each minute. In case of we checked the passage from both eyes to nasal cavity immediately after the dynamic check, we obtained oblique view immediately. If we didn't see the passage in either side of the orbit, we obtained oblique views of the orbit after checking the frontal film in 40 minutes. The instrument we used was Pin-hole Collimator with Gamma Camera(Siemens Orbiter, Hoffman Estates, IL, USA). Results: Among the 78 patients with dacryoscintigraphy, 35 patients were confirmed with passage into the nasal cavity from the anterior view. Among those 35 patients, 15 patients were confirmed with passage into the nasal cavity on both eyes, and it was able to observe better passage patterns through oblique view with a result of 8 on both eyes, 2 on left eye, and 1 on right eye. 20 patients had passage in left eye or right eye, among those patients 10 patients showed clear passage compared to the anterior view. 13 patients had possible passage, and 30 patients had no proof of motion of the tracer. To sum up, 21 patients (60%) among 35 patients showed clear pattern of passage with additional oblique views compared to anterior view. People responded obtaining oblique views though 5 points scale about the utility of passage identification helps make diagnoses the passage, passage delayed, and blockage of naso-lachrymal duct by showing the well-seen portions from anterior view. Also, when classifying passage to naso-lachrymal duct and flow to the skin, oblique views has higher chance of classification in case of epiphora (anterior:$4.14{\pm}0.3$, oblique:$4.55{\pm}0.4$). Conclusion: It is considered that if you obtain oblique views of the bilateral orbits in addition to anterior view during the dacryoscintigraphy, the ability of diagnose for reading will become higher because you will be able to see the areas that you could not observe from the anterior view so that you can see if it emitted after the naso-lachrymal duct and the flow of epiphora on the skin.

  • PDF

Effects of Fluid Resistance Coefficient on Wave Characteristics around Permeable Submerged Breakwater

  • Kim, Namhyeong;Woo, Sumin;Ko, Yongsu
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2014.06a
    • /
    • pp.244-245
    • /
    • 2014
  • Recently, the studies on submerged breakwater are increased due to needs considering the quality of water and the scenic view. In this paper, waves coming to permeable submerged breakwater coming with oblique angle are computed numerically by using wave pressure function. The wave pressure function throughout the analytical region including the fluid and submerged breakwaters is used. An unknown quantity expressed by the wave pressure function is simulated by boundary element method. The maximum reflection coefficient shows the tendency of decrease with the increase of oblique angle and The reflection coefficient shows the tendency of increase with the increase of the values of the linear dissipation coefficient and the added mass coefficient. It is means that the reflection coefficients are strongly dependent on the oblique angle and resistance coefficients.

  • PDF

Diagnosis and Arthroscopic Decompression of Impingement Syndrome of the Shoulder (견관절 충돌 증후군의 진단 및 관절경적 견봉 감압술)

  • Byun Ki-Yong;Kwon Soon-Tae;Lee Jang-Ik;Rhee, Kwang-Jin
    • Clinics in Shoulder and Elbow
    • /
    • v.1 no.1
    • /
    • pp.19-25
    • /
    • 1998
  • Appropriate clinical examination and imaging may lead to early diagnosis and treatment of the shoulder impingement syndrome, thus preventing progressing to a complete tear of rotator cuff. The impingement syndrome was caused by repeated entrapment and compression of supraspinatus tendon between the proximal end of humerus inferiorly, particullary its greater tuberosity. and one or m <)re component of coracoacromial arch superiorly. The purpose of this study is to critically, evaluate the result of twenty-five consecutive subacromial decompression with impingement syndrome and to assess the diagnostic accuracy of MR imaging by using oblique coronal and oblique sagittal plan. These patients were treated by arthroscopic subacromial decompression after their pains failed to improve with conservative therapy over three month. The average follow up was 25 month(range, 12 to 50). The mean age was 43 year old. The results were rated based on subjective response and the UCLA shoulder rating scale of the result. Ten patients(40%) were rated as excellent, 11patients(44%) were good. while four patients(16%) were fair. Radiologic evaluation suggested that the oblique sagittal plan of MRI can be helpful in evaluation of bony and soft-tissue structure of the coracoacromial arch and determining depth of bony resection. There were no infection or neurovascular injury. In reviewing our result, it appears that the arthroscopic subacromial decompression can be successful sugery for shoulder impingement syndrome and diagnostic accuracy of supplimentary oblique sagittal view of MRI was relatively higher than oblique coronal view alone for apprqpriate surgical plan.

  • PDF

Assessment of dynamic crushing and energy absorption characteristics of thin-walled cylinders due to axial and oblique impact load

  • Baaskaran, N.;Ponappa, K.;Shankar, S.
    • Steel and Composite Structures
    • /
    • v.28 no.2
    • /
    • pp.179-194
    • /
    • 2018
  • Reliable and accurate method of computationally aided design processes of advanced thin walled structures in automotive industries are much essential for the efficient usage of smart materials, that possess higher energy absorption in dynamic compression loading. In this paper, most versatile components i.e., thin walled crash tubes with different geometrical profiles are introduced in view of mitigating the impact of varying cross section in crash behavior and energy absorption characteristics. Apart from the geometrical parameters such as length, diameter and thickness, the non-dimensionalized parameters of average forces which control the plastic bending moment for varying thickness has explored in view of quantifying its impact on the crashworthiness of the structure. The explicit finite element code ABAQUS is utilized to conduct the numerical studies to examine the effect of parametric modifications in crash behavior and energy absorption. Also the simulation results are experimentally validated. It is evident that the circular cross-sectional tubes are preferable as high collision impact shock absorbers due to their ability in withstanding axial and oblique impact loads effectively. Furthermore, the specific energy absorption (SEA), crash force efficiency (CFE), plastic bending moment, peak force responses and its impact for optimally tailoring a design to cater the crashworthiness requirements are investigated. The primary outcome of the study is to provide sufficient information on circular tubes for the use of energy absorbers where impact oblique loading is expected.

A Study on the Usefulness of the New Foot Oblique Projection (새로운 발 사방향 검사법의 유용성에 관한 연구)

  • Kim, Min-Suk;Joo, Young-Cheol;Lee, Seung-Keun
    • Journal of radiological science and technology
    • /
    • v.44 no.5
    • /
    • pp.443-449
    • /
    • 2021
  • In this study, the purpose is to present the foot inclination angle for realizing an image similar to that of the existing examination method and to present the clinical usefulness of the new examination method through comparison between the existing examination method and the newly designed standing foot oblique projection. A foot phantom was used, and the magnification of the image according to the angle was quantitatively evaluated by attaching a nut to the position of the cuboid of the phantom. The internal oblique image acquired using a 30° wedge was set as the standard image. And that image was compared with the images acquired by changing the angle of the foot from 20° to 65° at intervals of 5°. Image evaluation was performed by 3 radiological technologists, and qualitative evaluation using a Likert 5-point scale for evaluation items of true oblique view and quantitative evaluation of the value obtained by measuring the diameter of a nut in each image were performed as image evaluation. For data analysis, reliability analysis between the measure and comparative analysis of the average value for each angle were performed. The qualitative evaluation score for each image was 4.5 to 5 points for most questions in the case of the standard image. And 4 points or less for most questions in the images with a foot angle of 45° or less, and an evaluation score close to the standard image was obtained in the image of 50° or more. And in the quantitative evaluation, the diameter of the nut was measured to be 9.28~9.56 mm. The qualitative evaluation showed a reliability of 0.95~1.0 and the quantitative evaluation was 0.62. As a result of comparing and analyzing the average of the quantitative and qualitative average values for each angle image, the group with the average value most similar to the standard image was images obtained at 55° and 60°, and in the post-analysis, the images of both groups were the same group as the standard image(p<0.01). As a result of this study, it was found that the angle of inclination of the foot for realizing the image most similar to the existing image in the standing foot oblique projection is 55°~60°. In addition, if this test method is applied to the clinic, it is believed that it will help prevent safety accidents such as falls during the test and improve test efficiency by minimizing the movement of patients for the test.