• Investigative Magnetic Resonance Imaging
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• 제3권1호
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• pp.13-19
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• 1999

MRI imaging provides many benefits such as noninvasive, 3-dimensional imaging capabilities. But it has relatively serious drawback that is the long data collection time, compared with other imaging modality. Many studies have been performed for fast MR imaging. But EPI and SEPI (4-6) are required to expensive hardware. In this paper, we introduce to Burst imaging technique. It can reduce imaging time by use of a mulitple RF excitation technique. Further it is easily implemented to the normal MRI system. But a pixel profile in the conventional burst sequence is so poor that excited area by burst sequence is a small portion of a pixel. This causes poor signal to noise ratio in burst image. therefore frequency sweeping of RF pulse for burst imaging sequence is proposed to improve pixel profile. A burst pulse train is shaped by liner or nonlinear frequency sweeping function so that all the spins within a pixel are excited, thereby improving the signal to noise ratio. It also shows that the pixel profiles are dependent on how frequency sweep is made. Computer simulations with Bloch equation and experimental results obtained using a 1.0 T NMR imaging system are presented.

• Nuclear Medicine and Molecular Imaging
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• 제43권3호
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• pp.179-195
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• 2009

Scince $^{201}$TI was introduced as a myocardial perfusion imaging agent in the early 1970s, scintigraphic evaluation of myocardial perfusion for the diagnosis of coronary artery disease is a valuable noninvasive diagnostic imaging modality. Stress radionuclide myocardial perfusion imaging is widely accepted to have high diagnostic and prognostic use in the assessment of patients with known or suspected coronary artery disease. With wise use of this nonivasive imaging technique, more patients are referred for stress perfusion imaging. Until now various protocols for stress testing and myocardial imaging were developed and used in worldwide. This article presented various protocols of stress testing and myocardial imaging for clinical use.

• Current Optics and Photonics
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• 제7권5호
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• pp.537-544
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• 2023

Differential phase contrast (DPC) microscopy, a central quantitative phase imaging (QPI) technique in cell biology, facilitates label-free, real-time monitoring of intrinsic optical phase variations in biological samples. The existing DPC imaging theory, while important for QPI, is grounded in paraxial diffraction theory. However, this theory lacks accuracy when applied to high numerical aperture (NA) systems that are vital for high-resolution cellular studies. To tackle this limitation, we have, for the first time, formulated a nonparaxial DPC imaging equation with a transmission cross-coefficient (TCC) for high NA DPC microscopy. Our theoretical framework incorporates the apodization of the high NA objective lens, nonparaxial light propagation, and the angular distribution of source intensity or detector sensitivity. Thus, our TCC model deviates significantly from traditional paraxial TCCs, influenced by both NA and the angular variation of illumination or detection. Our nonparaxial imaging theory could enhance phase retrieval accuracy in QPI based on high NA DPC imaging.

• Imaging Science in Dentistry
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• 제53권4호
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• pp.335-344
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• 2023

Purpose: This bibliometric analysis aimed to provide a comprehensive overview of the characteristics, trends, and level of diagnostic efficacy of studies on cone-beam computed tomography (CBCT) published in Imaging Science in Dentistry (ISD) from 2011 to 2022. Materials and Methods: Publications related to CBCT identified in the electronic collection of ISD were selected according to eligibility criteria by 2 independent reviewers who collected data on the characteristics of the articles (year, authors, and country). The type and topic of studies were analyzed using VOSviewer v.1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, Netherlands). The research articles were classified according to the hierarchical scale of diagnostic efficacy. Results: Of the 236 articles included, most were from South Korea and Brazil. Bong-Hae Cho and Yun-Hoa Jung were the most prolific authors on the topic of CBCT. The most frequently published types of studies were cross-sectional and laboratory-based. The most popular topics WERE related to the diagnosis of pathologies and/or alterations, as well as anatomical variations. On the diagnostic efficacy scale, most studies were rated level 1 (technical efficacy) or 2 (diagnostic accuracy efficacy). Conclusion: A steady increase was observed in publications related to CBCT, which are of both clinical and academic interest. The trends in these publications were analyzed, revealing that most are cross-sectional studies primarily exploring the capabilities of CBCT in diagnosing pathologies and/or changes in the oral and maxillofacial complex. These studies were typically classified as level 1 or 2 on the diagnostic efficacy scale.

• Imaging Science in Dentistry
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• 제47권4호
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• pp.233-239
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• 2017

Purpose: This study was performed to quantify the repeat rate of imaging acquisitions based on different clinical examinations, and to assess the prevalence of error types in intraoral bitewing and periapical imaging using a digital complementary metal-oxide-semiconductor(CMOS) intraoral sensor. Materials and Methods: A total of 8,030 intraoral images were retrospectively collected from 3 groups of undergraduate clinical dental students. The type of examination, stage of the procedure, and reasons for repetition were analysed and recorded. The repeat rate was calculated as the total number of repeated images divided by the total number of examinations. The weighted Cohen's kappa for inter- and intra-observer agreement was used after calibration and prior to image analysis. Results: The overall repeat rate on intraoral periapical images was 34.4%. A total of 1,978 repeated periapical images were from endodontic assessment, which included working length estimation (WLE), trial gutta-percha (tGP), obturation, and removal of gutta-percha (rGP). In the endodontic imaging, the highest repeat rate was from WLE (51.9%) followed by tGP (48.5%), obturation (42.2%), and rGP (35.6%). In bitewing images, the repeat rate was 15.1% and poor angulation was identified as the most common cause of error. A substantial level of intra- and inter-observer agreement was achieved. Conclusion: The repeat rates in this study were relatively high, especially for certain clinical procedures, warranting training in optimization techniques and radiation protection. Repeat analysis should be performed from time to time to enhance quality assurance and hence deliver high-quality health services to patients

• 대한핵의학회지
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• 제38권2호
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• pp.131-139
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• 2004

Small animal models are extensively utilized in the study of biomedical sciences. Current animal experiments and analysis are largely restricted to in vitro measurements and need to sacrifice animals to perform tissue or molecular analysis. This prevents researchers from observing in vivo the natural evolution of the process under study. Imaging techniques can provide repeatedly in vivo anatomic and molecular information noninvasively. Small animal imaging systems have been developed to assess biological process in experimental animals and increasingly employed in the field of molecular imaging studies. This review outlines the current developments in nuclear medicine imaging instrumentations including fused multi-modality imaging systems for small animal imaging.

• 대한자기공명의과학회:학술대회논문집
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• 대한자기공명의과학회 2003년도 제8차 학술대회 초록집
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• pp.37-37
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• 2003

To assess the merits and demerits of postcontrast fat-suppressed (FS) brain MR imaging in children in the evaluation of various enhancing lesions, compared with postcontrast conventional or Magnetization Transfer (MT) imaging. 대상 및 방법： We reviewed patients with enhancing lesion on brain MR imaging who underwent both FS imaging and one of conventional or MT imaging as a postcontrast T1-weighted brain MR imaging. Inclusion criteria of our study were as follows： MR studies should be peformed within one-year interval and showed no significant interval change of imaging findings. Thirty-four patients (21 male, 13 female; mean age, 8 years) with 43 enhancing lesions (19 intra-axial, 19 extra-axial, and 5 orbital location) were included in this study, Twenty-one pairs of FS and conventional imaging, and 15 pairs of FS and MT imaging were available. Two radiologists visually assessed the lesion conspicuity and the presence of flow or susceptibility artifacts in a total of 36 pairs of MR imaging by consensus. For 21 measurable lesions (19 pairs of FS and conventional imaging, 5 pairs of FS and MR imaging), contrast ratio between the lesion and the normal brain( ［SIlesion-SIwater］/[SInormal brain-SIwater]) were calculated and compared.

• 대한한방부인과학회지
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• 제33권3호
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• pp.80-94
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• 2020

Objectives: The purpose of this review is to analyze the domestic study trends of clinical use of Digital Infrared Thermal Imaging (DITI) as a diagnosis instrument on obstetrics and gynecological diseases in Korean literature. Methods: We searched for clinical studies using DITI in the journal of Korean obstetrics & gynecology, National Digital Science Library, Research Information Sharing Service, Korean Medical Database up to May 2020. After searching studies, we selected studies and analyzed according to disease. Results: 18 clinical studies were published in two kinds of academic journals. There were 4 studies about dysmenorrhea and menopausal symptoms, 2 studies about postpartum disease and hypercryalgesia, 1 study about amenorrhea, premenstrual syndrome, leukorrhea, infertility, polycystic ovary syndrome and hot flush. Conception vessel was frequently used for DITI measurement, followed by stomach meridian. The temperatures of abdomen (CV4, CV12), face (HN3), upper and lower limb (PC8, LU4, LR3, ST32) were commonly measured. Conclusions: This study shows that DITI could be one of effective diagnosis instrument for obstetrics and gynecological diseases. More well-designed clinical studies using DITI will be needed.

• 대한불안의학회지
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• 제3권2호
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• pp.91-96
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• 2007

Panic disorder is a common psychiatric illness that causes considerable morbidity. However, the biological basis of panic disorder remains unclear. In this report, we present and summarize the current literature on functional neuroimaging studies related to the neurobiology of panic disorder. The findings were summarized and divided into six groups : (1) known brain structures related to anxiety, especially panic disorder ; (2) structural results ; (3) functional imaging studies at rest ; (4) functional imaging studies with challenge testing ; (5) neuroreceptor studies ; and (6) changes in the treatment of panic disorder. Based on the findings of these neuroimaging studies, it seems as though panic disorder involves the hippocampal and parahippocampal areas, including the amygdala, as well as some cortical regions, such as the temporal and prefrontal cortices. Panic disorder is known to be associated with an imbalance between the right and left hemispheres of the brain at rest or during panic attacks. During a panic attack, patients with panic disorder are likely to experience an increase in local activity in the cingulate, insula, midbrain, and so on. On the other hand, a widespread reduction in the cortical areas has also been reported in most provocation studies. Thus, panic disorder may be related to the excess activation of the fear networks in response to subtle environmental cues and insufficient inhibition from higher cortical control areas ; however ; further studies are recommended in order to fully understand the neurobiology of panic disorder.

• 대한정형외과 초음파학회지
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• 제1권1호
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• pp.40-49
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• 2008

고관절은 인체에서 가장 깊이 위치라는 관절인데다가 고관절에 생긴 병변에 의한 증상은 대부분 모호하고 혼란스럽다. 이러한 이유로 고관절의 영상검사에 대한 연구와 개발은 매우 활발하게 진행되었다. 그 결과 현재는 단순 방사선 사진으로부터 복잡한 자기공명관절조영술에 이르기까지 다양한 방법이 사용되고 있다. 이 간단한 글에서 저자는 각 영상 검사법의 장단점과 흔한 고관절 질환의 영상 진단에 대해 다루고자 한다. 이러한 고관절의 영상 검사법의 중요성은 그것이 임상적인 연관이 있을 때뿐이다. 만일 우리가 각 검사법과 해당 질환들의 특성을 잘 알고 있다면 환자에 대한 가장 이상적인 접근이 가능할 것이지만 그렇지 못하다면 비싼 영상 검사는 의미 없는 그림에 지나지 않을 것이기 때문이다.