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MultiBand SENSE를 사용한 Corticospinal tract Diffusion Tensor Imaging의 유용성 평가
김혁,지창룡,김세영,김윤국,박순규 대한자기공명기술학회 2018 대한자기공명기술학회 학술대회 Vol.2018 No.04
Purpose:In this study to evaluate the clinical usefulness of diffusion tensor imaging(DTI) using Multiband(MB) SENSE, which is a technique for simultaneous excitation and acquisition of multiple slices, in the corticospinal tract. Object and method:We obtained images in two ways: conventional-DTI and MB SENSE DTI (MB factor : 2, 3) in 7 healthy adult volunteers (male: 6, female: 1, mean age: 33).The ROI was set in the pyramidal tract of the pons and the posterior limb of the internal capsule, and the tracking of the corticospinal tract through the two ROIs was performed. For quantitative analysis, fractional anisotropy (FA), apparent diffusivity coefficient (ADC), length of the tracked fiber, and number of white matter fibers were measured by two radiology technologists. For qualitative analysis, The accuracy of the pyramidal tract, the posterior limb of the internal capsule and the tracked white matter fibers were evaluated by 5 person who work at MRI over 5 years that were classified as grade 4 ;poor (1), fair (2), good (3), excellent (4) Result:The FA of the pyramidal tract of the pons was 0.508 ± 0.165 for conventional DTI, 0.486 ± 0.140 for MBf2, and 0.433 ± 0.150 for MBf3. The ADC values were measured as 0.783 ± 0.194, 0.825 ± 0.197 and 1.022 ± 0.228 in conventional DTI, MBf2 and MBf3, respectively. The FA of internal capsule was 0.521 ± 0.185for conventional DTI, 0.538 ± 0.175 for MBf2, and and 0.506 ± 0.161 for MBf3. ADC values were measured as 0.719 ± 0.119, 0.730 ± 0.105 and 0.865 ± 0.172 respectively in conventional DTI, MBf2 and MBf3. There was no significant difference between conventional DTI and MBf2 in FA and ADC. The mean lengths (mm) of the white matter fibers measured in the corticospinal tract were 124.486 ± 18.523, 115.493 ± 19.568, and 100.224 ± 18.368 for conventional DTI, MBf2 and MBf3. The number of tracked white matter fibers was 1294.3, 1090.6, 123.3. for conventional DTI, MBf2 and MBf3. As MBf increased, the length and number of white fibers decreased. In MBf3, the number of white fibers decreased sharply. In the qualitative evaluation, the accuracy of the pyramidal tract was 3.86 ± 0.14, 3.83 ± 0.06 and 2.71 ± 0.49 for conventional DTI, MBf2 and MBf3. MBf2 was similar to conventional image, but MBf3 was remarkably low. The accuracy of the internal capsule was 3.94 ± 0.09, 3.91 ± 0.09and 3.4 ± 0.01for conventional DTI, MBf2 and MBf3.The number of tracked white matter fibers was 3.94±0.09, 3.91±0.1 and 2.54±0.26. for conventional DTI, MBf2 and MBf3. When the number of white matter fibers was visually observed, there was no significant difference between conventional and MBf2 images. Conclusion:MB SENSE is a method that enables simultaneous excitation and acquisition of multiple volumes in a sing shot EPI sequence. The main advantage of the diffusion image using MB SENSE is that the acquisition time of the image is reduced by about 40% when MBf2 is used. Quantitative and qualitative evaluation of images showed little difference between conventional and MBf2 DTI. Therefore, diffusion tensor imaging using MBf2 may be helpful for patients with severe motion or discomfort during long examination time.
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Long Bone 검사시 촬영 방식에 따른 영상 왜곡률 평가
박세훈(Se-Hoon Park),지창룡(Chang-Ryong Ji):윤석민(Seok-Min Yun),임재식(Jae-Sik Im):박순규(Soon-Kyu Park) 대한영상의학기술학회 2016 대한영상의학기술학회 논문지 Vol.2016 No.1
목 적 : 일반촬영에서 하지(Lower extremity)나 전 척추(Whole spine) 검사 시 검사부위가 detector에 한 번에 들어가지 않기 때문에 두 번에서 세 번에 나누어 영상을 획득한 후 영상을 합성하는 방법을 사용하고 있다. 이때 각 회사의 장비마다 영상을 획득하는 방식이 다른데, 각각의 방식이 영상에서 구간별로 어느 정도 왜곡이 생기는지 측정하여 수치화하고 왜곡이 가장 작은 방식을 알아보고자 하였다. 대상 및 방법 : 실험에는 본원에서 사용 중인 세 가지 방식을 대상으로 하였으며 첫째, CR Long cassette를 이용하는 방식(A 방식), 둘째, tube는 고정되어있고 detector만 이동하며 영상을 획득하는 방식(B 방식), 셋째, detector가 이동 할 때 tube가 tilt 되며 각도가 들어가는 방식(C 방식)을 비교하였다. 실험은 장비별로 촬영 조건을 동일하게 고정시켜 진행하였으며 검사 시 환자의 soft tissue 두께에 따른 왜곡을 고려하여 팬텀 후방에 3cm의 투과성 스티로폼을 부착 후 실험을 진행하였다. 팬텀은 3x3x5cm 사각기둥 알루미늄 5개를 18cm 간격으로 세워서 만든 자체 제작 팬텀을 이용하였으며 왜곡률은 실험의 정확도를 위해 5회 측정 후 영상에서 사각기둥 알루미늄의 길이를 이용해 구하였다. 결 과 : 각 방식의 구간별 평균 왜곡률은 중심부에서는 세가지 방식 모두 103.3%의 왜곡을 보였으며, 중심부에서 상방 18cm 지점에서는 A 방식은 118.0%, B 방식은 120.6%, C 방식은 118.6%의 왜곡률을 보였고, 36cm 지점에서는 A 방식은 128.6%, B 방식은 134.0%, C 방식은 132.6%의 왜곡률을 보였다. 또한, 중심부 기준 하방 18cm 지점에서는 A 방식은 114.6%, B 방식은 118.0%, C 방식은 116.6%의 왜곡률을 보였고, 36cm 지점에서는 A 방식은 133.3%, B 방식은 137.3%, C 방식은 136.0%의 왜곡률을 보였다. 결 론 : 실험결과 세 가지 방식중에서 DR을 이용하는 B 방식과 C 방식의 왜곡률 차이는 크지 않았으나 CR을 이용하는 A 방식이 왜곡률이 상대적으로 가장 작았다. 이는 CR을 이용하는 방식이 Flim 과 피사체 사이의 거리가 짧아, 거리에 따른 왜곡률이 작게 측정된 것으로 판단된다. Purpose : When taking general radiographs of the lower extremity or whole spine, it is customary to take it multiple times and stitch the images. The reason of doing it is that the part of body under the inspection normally does not fit into the scope of the imaging device, however, this leads to different ways of taking radiographs depending upon the device used. In this study, we aim to measure the distortion rate of different ways of taking radiographs. Materials and Methods : Three different methods are compared in this study. First we try using a CR long cassette (A). Secondly, we only use a detector with a fixed tube (C). Lastly, we make the tube tilt when the detector is moving (C). We measure the distortion rate of each method using bespoke phantoms. 5 aluminium cubes standing next to each other are used as phantoms. In order to take into account the distortion due to the width of the patents琅soft tissue, we attach 3cm thick styrofoam to the phantom. The distortion rates are obtained by measuring the length of the aluminium cube five times. Result : The average distortion rate of each section is 103.3% from the center. At the point 18cm above the center, (A) showed 118%, (B) showed 120.6, and (C) showed 118.6% of the distortion rate. At 36cm above the center, we had 128.6 for (A), 134.0% for (B), and 132.6% for (C). At the point 18cm below the center, (A) showed 114.6%, (B) showed 118.0, and (C) showed 116.6% of the distortion rate. Finally, at 36cm below the center, we obtained the distortion rate of 133.3 for (A), 137.3% for (B), and 136.0% for (C). Conclusion : Our study concludes that there is a marginal difference in the result between the method (B) and (C) while (A) produced the lowest distortion rate. This can be attributed to the fact that (A) method allows the closest distance between the film and the object of the radiograph.
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