• Imaging Science in Dentistry
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• v.54 no.3
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• pp.276-282
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• 2024

Purpose: This study aimed to assess the performance of 2-dimensional (2D) imaging with microscopy coils in delineating teeth and periodontal tissues compared with conventional 3-dimensional(3D) imaging on a 3 T magnetic resonance imaging (MRI) unit. Materials and Methods: Twelve healthy participants (4 men and 8 women; mean age: 25.6 years; range: 20-52 years) with no dental symptoms were included. The left mandibular first molars and surrounding periodontal tissues were examined using the following 2 sequences: 2D proton density-weighted (PDw) images and 3D enhanced T1 high-resolution isotropic volume excitation (eTHRIVE) images. Two-dimensional MRI images were taken using a 3 T MRI unit and a 47 mm microscopy coil, while 3D MRI imaging used a 3 T MRI unit and head-neck coil. Oral radiologists assessed dental and periodontal structures using a 4-point Likert scale. Inter- and intra-observer agreement was determined using the weighted kappa coefficient. The Wilcoxon signed-rank test was used to compare 2D-PDw and 3D-eTHRIVE images. Results: Qualitative analysis showed significantly better visualization scores for 2D-PDw imaging than for 3D-eTHRIVE imaging (Wilcoxon signed-rank test). 2D-PDw images provided improved visibility of the tooth, root dental pulp, periodontal ligament, lamina dura, coronal dental pulp, gingiva, and nutrient tract. Inter-observer reliability ranged from moderate agreement to almost perfect agreement, and intra-observer agreement was in a similar range. Conclusion: Two-dimensional-PDw images acquired using a 3 T MRI unit and microscopy coil effectively visualized nearly all aspects of teeth and periodontal tissues.

• International Journal of Stem Cells
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• v.16 no.4
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• pp.363-375
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• 2023

Stem cells are the foundational cells for every organ and tissue in our body. Cell-based therapeutics using stem cells in regenerative medicine have received attracting attention as a possible treatment for various diseases caused by congenital defects. Stem cells such as induced pluripotent stem cells (iPSCs) as well as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and neuroprogenitors stem cells (NSCs) have recently been studied in various ways as a cell-based therapeutic agent. When various stem cells are transplanted into a living body, they can differentiate and perform complex functions. For stem cell transplantation, it is essential to determine the suitability of the stem cell-based treatment by evaluating the origin of stem, the route of administration, in vivo bio-distribution, transplanted cell survival, function, and mobility. Currently, these various stem cells are being imaged in vivo through various molecular imaging methods. Various imaging modalities such as optical imaging, magnetic resonance imaging (MRI), ultrasound (US), positron emission tomography (PET), and single-photon emission computed tomography (SPECT) have been introduced for the application of various stem cell imaging. In this review, we discuss the principles and recent advances of in vivo molecular imaging for application of stem cell research.

• Investigative Magnetic Resonance Imaging
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• v.23 no.1
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• pp.26-33
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• 2019

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.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.75-83
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• 2007

Elasticity is an important physical property of biological tissues. Differences in elasticity can help facilitate the diagnosis of tumors and their extent. Magnetic Resonance Elastography (MRE) tries to visualize images of tissue elasticity by externally applying shear stress on the surface of an imaging object. Applied shear stress induces internal displacements that can be measured from MR phase images. In order to conduct MRE imaging experiments, we need to first develop a vibrator. We found that there does not exist enough technical information to design the MRE vibrator. In this paper, we describe the theory, design and construction of an MRE vibrator. We report the performance of the developed vibrator using two different test methods. We found that the vibrator successfully induces enough internal displacements that can be imaged using an MRI scanner. We suggest future studies of numerous MRE imaging experiments using the vibrator.

• Journal of Sensor Science and Technology
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• v.26 no.4
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• pp.245-250
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• 2017

A novel method to implement a birdcage-type receiving coil sensor for use in a magnetic resonance imaging(MRI) system has been demonstrated employing a flexible printed circuit board (FPCB) fabrication technique. Unlike the conventional methods, the two-dimensional shape of the coil sensor is first implemented as a FPCB and then it is attached to the surface of a cylindrical supporting structure to implement the three-dimensional birdcage-type coil sensor. The proposed method is very effective to implement object-specific MRI coil sensors especially for small animal measurements in research and preclinical applications since the existing well-developed FPCB-based techniques can easily meet the requirements on accuracies and costs during coil implement process. The performances of the coil sensor verified through $^1H$ 1.5T MRI measurements for small animals and it showed excellent characteristics by providing a high spatial precision and a high signal-to-noise ratio.

• Dementia and Neurocognitive Disorders
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• v.16 no.2
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• pp.48-53
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• 2017

Background and Purpose Torrance Tests of Creative Thinking (TTCT) is a well-known and commonly used measure of creativity. However, the TTCT-induced creative hemodynamic brain activity is rarely revealed. The purpose of this study is to elucidate the neural correlates of creative thinking in the setting of a modified version of the figural TTCT adapted for an functional magnetic resonance imaging (fMRI) experiment. Methods We designed a blocked fMRI experiment. Twenty-five participants (11 males, 14 females, mean age $19.9{\pm}1.8$) were asked to complete the partially presented line drawing of the figural TTCT (creative drawing imagery; creative). As a control condition, subjects were asked to keep tracking the line on the screen (line tracking; control). Results Compared to the control condition, creative condition revealed greater activation in the distributed and bilateral brain regions including the left anterior cingulate, bilateral frontal, parietal, temporal and occipital regions as shown in the previous creativity studies. Conclusions The present revealed the neural basis underlying the figural TTCT using fMRI, providing an evidence of brain areas encompassing the figural TTCT. Considering the significance of a creativity test for dementia patients, the neural correlates of TTCT elucidated by this study may be valuable to evaluate the brain function of patients in the clinical field.

• Investigative Magnetic Resonance Imaging
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• v.23 no.3
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• pp.220-227
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• 2019

Purpose: To evaluate the usefulness of wash-in color map in detecting early enhancement of prostate focal lesion compared to whole dynamic contrast-enhanced MRI (DEC MRI) images. Materials and Methods: This study engaged 50 prostate cancer patients who underwent multiparametric MRI and radical prostatectomy as subjects. An expert [R1] and a trainee [R2] independently evaluated early enhancement and recorded the time needed to review 1) a wash-in color map and 2) whole DCE MRI images. Results: The review of whole DCE images by R1 showed fair agreement with color map by R1, whole images by R2, and color map by R2 (weighted kappa values = 0.59, 0.44, and 0.58, respectively). Both readers took a significantly shorter time to review the color maps as compared to whole images (P < 0.001). Conclusion: A trainee could achieve better agreement with an expert when using wash-in color maps than when using whole DCE MRI images. Also, color maps took a significantly shorter evaluation time than whole images.

• Journal of International Academy of Physical Therapy Research
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• v.10 no.1
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• pp.1725-1733
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• 2019

Background: In some clinical guidelines followed in clinical practice, nonsurgical treatments are recommended as the primary intervention for patients with lumbar disc herniation (LDH). However, the effect of a therapeutic exercise program based on stabilization of the lumbar spine for treatment of multilevel LDH has not been evaluated thoroughly. Objective: To investigate the effects of therapeutic exercise on pain, physical function, and magnetic resonance imaging (MRI) findings in a patient with multilevel LDH. Design: Case Report Methods: A 43-year-old female presented with low back pain, radicular pain and multilevel LDH (L3-L4, L4-L5, L5-S1). The therapeutic exercise program was conducted. in 40-min sessions, three times a week, for 12 weeks. Low back and radicular pain, lumbar disability, and physical function were measured before and after 6 and 12 weeks of the exercise program. MRI was performed before and after 12 weeks of the program. Results: After 6 and 12 weeks of the therapeutic exercise, low back and radicular pain and lumbar disability had decreased, and lumbar range of motion (ROM) was improved bilaterally, compared with the initial values. Also improved at 6 and 12 weeks were isometric lumbar strength and endurance, and the functional movement screen score. The size of disc herniations was decreased on MRI obtained after 12 weeks of therapeutic exercise than on the pre-exercise images. Conclusions: We observed that therapeutic exercise program improved spinal ROM, muscle strength, functional capacity, and size of disc herniation in LDH patient.

• Journal of radiological science and technology
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• v.44 no.1
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• pp.31-37
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• 2021

This study aim of quantitative assessment of Noise Power Spectrum(NPS) and image characteristics of by acquired the optimal image for noise characteristics and quality assurance by using magnetic resonance imaging(MRI). MRI device was (MAGNETOM Vida 3.0T MRI; Siemense healthcare system; Germany) used and the head/neck shim MR receive coil were 20 channels coil and a diameter 200 mm hemisphere phantom. Frequency signal could be acquired the K-space trajectory image and white image for NPS. The T2 image highest quantitatively value for NPS finding of showed the best value of 0.026 based on the T2 frequency of 1.0 mm-1. The NPS acquired of showed that the T1 CE turbo image was 0.077, the T1 CE Conca2 turbo image was 0.056, T1 turbo image was 0.061, and the T1 Conca2 turbo image was 0.066. The assessment of NPS image characteristics of this study were to that could be used efficiently of the MRI and to present the quantitative evaluation methods and image noise characteristics of 3.0T MRI.

• Investigative Magnetic Resonance Imaging
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• v.24 no.3
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• pp.154-161
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• 2020

Purpose: A CT angiography spot sign (CTA-spot) is a significant predictor of the early expansion of an intracerebral hemorrhage (ICH-Ex). Dynamic-susceptibility-contrast magnetic resonance imaging (DSC-MRI) can track the real-time leaking of contrast agents. It may be able to indicate active bleeding, like a CTA-spot. Materials and Methods: From September 2014 to February 2017, we did non-contrast CT, CTA, and DSC-MRI examinations of seven patients with acute ICH. We investigated the time from symptom onset to the first contrast-enhanced imaging. We evaluated the time course of the contrast leak within the ICH at the source image of the DSC-MRI and the volume change of ICH between non-contrast CT and DSC-MRI. We compared the number of slices showing CTA-spots and DSC-MRI leaks. Results: The CTA-spot and DSC-MRI leak-sign were present in four patients, and two patients among those showed ICH-Ex. The time from the symptom onset to CTA or DSC-MRI was shorter for those with a DSC-MRI leak or CTA-spot than for three patients without either (70-130 minutes vs. 135-270 minutes). The leak-sign began earlier, lasted longer, and spread to more slices in the patients with ICH-Ex than in those without ICH-Ex. The number of slices of the DSC-MRI leak and the number of the CTA-spot were well correlated. Conclusion: DSC-MRI can demonstrate the leakage of GBCA within hyperacute ICH, showing the good contrast between hematoma and contrast. The DSC-MRI leakage sign could be related to the hematoma expansion in patients with ICH.