• 한국멀티미디어학회논문지
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• 제8권4호
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• pp.492-501
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• 2005

본 논문에서는 스테레오 안저 영상에서 시각신경원반의 깊이 값을 고려하는 시각신경원반과 시각신경패임 영역의 새로운 분할방법을 제안하였다. 스테레오 안저 영상에서 스테레오 정합을 수행할 때 발생할 수 있는 오류의 요인들을 분석하여 보정 방법들을 구현하였다. 또한, 시각신경원반과 시각신경패임 영역을 정확하게 추출하기 위하여 시각신경원반의 3차원 깊이 정보를 이용하는 새로운 동적 윤곽선 모델을 제안하였다. 다양한 스테레오 안저 영상을 대상으로 한 실험결과, 제안한 방법이 시각신경원반과 시각신경패임을 효과적으로 분할 할 수 있음을 확인하였다.

• Biomolecules & Therapeutics
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• 제3권2호
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• pp.149-153
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• 1995

Nitric oxide (NO) has been regarded as one of the neurotransmitters of nonadrenergic, noncholinergic (NANC) nerve stimulation in rabbit corpus cavernosum, rat gastric fundus and human intestine. PIANO (photo-induced adequate nitric oxide) is a very useful tool to investige the role of NO in various smooth muscles where NO is a mediator. The present study was undertaken to compare the physiological responses of the rat gastric smooth muscle in response to NANC nerve stimulation and to PIANO. Photolysis of L-NAME, D-NAME and streptozotocin (572) by UV light in the bathing medium caused relaxation of rat gastric fungus that contracted with carbachol, but was resistant to tetrodotoxin (TTX, 1 $\mu$M). Electrical stimulation (20 V, 2~32 Hz, 0.2 msec, 10s) of the gastric fundus, in the presence of atropine and guanethidine, induced frequency-dependent, TTX-sensitive relaxation. Sodium nitroprusside (1 nM-10 $\mu$M), a NO donor, mimicked the relaxations observed after NANC-stimulation or PIANO. Furthermore, PIANO caused UV light exposure time-dependent increase of CGMP in rat gastric fungus strips. These results provide another evidence indirectly that NO is one of the mediators of the NANC inhibitory nerve stimulation in the rat gastric fundus.

• 대한의용생체공학회:의공학회지
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• 제16권2호
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• pp.121-128
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• 1995

Information about retinal blood vessels can be used in grading disease severity or as part of the process of automated diagnosis of diseases with ocular menifestations. In this paper, we address the problem of detecting retinal blood vessels and optic disk (papilla) in eye-fundus images. We introduce an algorithm for feature extraction based on Fuzzy Clustering algorithm (fuzzy c-means). A method of finding the optic disk (papilla) is proposed in the eye-fundus images. Additionally, the inrormations such as position and area of the optic disk are extracted. The results are compared to those obtained from other methods. The automatic detection of retinal blood vessels and optic disk in the eye-rundus images could help physicians in diagnosing ocular diseases.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.636-638
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• 2022

본 논문은 의료진단 검출 분야에서 혈관, 신경조직, 망막 손상 그리고 다양한 심혈관계 질환과 치매까지 진단하는 데 유용하게 사용하고 있는 안저 영상에 CNN(Convolution Neural Network) 알고리즘을 적용하고 녹내장 병변을 검출하기 위한 연구를 진행한다. 실험을 위하여 정상 안저 영상과 녹내장 병변이 있는 안저 영상으로 구성된 데이터 세트를 AlexNet으로 분류하고 그 성능을 확인하였다.

• The Korean Journal of Physiology and Pharmacology
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• 제14권5호
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• pp.317-324
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• 2010

We elucidated the distribution of interstitial cells of Cajal (ICC) in human stomach, using cryosection and $c-Kit$ immunohistochemistry to identify $c-Kit$ positive ICC. Before $c-Kit$ staining, we routinely used hematoxylin and eosin (HE) staining to identify every structure of human stomach, from mucosa to longitudinal muscle. HE staining revealed that the fundus greater curvature (GC) had prominent oblique muscle layer, and $c-Kit$ immunostaining $c-Kit$ positive ICC cells were found to have typical morphology of dense fusiform cell body with multiple processes protruding from the central cell body. In particular, we could observe dense processes and ramifications of ICC in myenteric area and longitudinal muscle layer of corpus GC. Interestingly, $c-Kit$ positive ICC-like cells which had morphology very similar to ICC were found in gastric mucosa. We could not find any significant difference in the distribution of ICC between fundus and corpus, except for submucosa where the density of ICC was much higher in gastric fundus than corpus. Furthermore, there was no significant difference in the density of ICC between each area of fundus and corpus, except for muscularis mucosa. Finally, we also found similar distribution of ICC in normal and cancerous tissue obtained from a patient who underwent pancreotomy and gastrectomy. In conclusion, ICC was found ubiquitously in human stomach and the density of ICC was significantly lower in the muscularis mucosa of both fundus/corpus and higher in the submucosa of gastric fundus than corpus.

• 대한안과학회지
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• 제59권12호
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• pp.1160-1165
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• 2018

목적: 증상이 있는 후유리체박리 환자에서 망막열공을 진단하기 위한 초광각안저촬영기의 눈방향전환 촬영술의 유용성을 알아보고자 하였다. 대상과 방법: 비문증 또는 광시증으로 내원하여 후유리체박리를 진단받은 환자의 의무기록을 후향적으로 조사하였다. 초광각안저촬영술의 눈방향전환 촬영 사진 4장을 이용하여 독립적으로 망막열공을 확인하였고, 눈방향전환 초광각안저촬영술의 망막열공 진단에 대한 민감도와 특이도를 구하였다. 결과: 총 94명의 94안이 연구에 포함되었다. 산동 후 시행한 안저검사에서 42안(45%)이 망막열공을 진단받았다. 망막열공 진단에 대한 눈방향전환 초광각안저촬영술의 민감도는 98% (95% 신뢰구간 88-100%), 특이도는 98% (95% 신뢰구간 90-100%)였다. 전체 망막열공 58개 중에 눈방향전환 초광각안저촬영술에서 상측 28개(97%)와 하측 10개(100%), 비측 6개(100%), 이측 13개(100%)의 망막열공이 확인되었다. 결론: 눈방향전환 초광각안저촬영술은 증상이 있는 후유리체박리 환자에서 망막열공을 진단하는 데 유용하다. 그렇지만 모든 증례에서 산동 후 안저검사를 대체할 수는 없었다.

• 대한의용생체공학회:의공학회지
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• 제24권2호
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• pp.91-97
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• 2003

본 논문에서는 안저 영상에서 시신경유두의 계층적인 검출 방법을 제안하였다. 혈관 정보. 영상의 복잡성 등을 포함하는 안저의 해부학적 지식에 기반한 선행 정보를 이용함으로써 시신경유두의 윤곽선을 검출하였다. 전체적인 처리과정은 크게 3 단계로 나누어진다. 먼저, 처리 과정을 단순화하기 위한 선행 지식으로 이용되는 시신경유두의 근사적인 크기와 위치를 계산하기 위하여 시신경유두를 포함하는 관심영역을 설정하였다. 그런 다음. 설정된 관심영역 내에서 watershed알고리듬을 이용하여 안저 영상을 분할하였고 분할된 영역을 병합함으로써 시신경유두의 초기 윤곽선을 검출하였다. 최종적으로 정확한 윤곽선을 검출하기 위하여 혈관의 심한 간섭 등으로 인해 손상된 윤곽선 부분들을 탐색하고 이들을 제거 및 보정하였다.

• 한국임상수의학회지
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• 제30권1호
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• pp.27-31
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• 2013

We investigated the effects of Ponciri Fructus (PF) and Aurantii Fructus Immaturus (AI) on the cicular and longitudinal smooth muscle of rat gastric fundus. Methanol extracts of PF (PFM) and AI (AIM), water-fractions (PFW, AIW) and chloroform-fractions (PFC, AIC) of the extracts induced relaxation in the rat fundic circular muscle pre-contracted by U46619. All extracts showed relaxation without significant differences among the extracts. In the longitudinal smooth muscle, PFM and its water fraction, PFW, showed multiphasic effects, fast relaxation and rebound contraction followed by lasting relaxation. AIM and AIW showed diphasic effects, transient contraction followed by lasting relaxation. However, PFC and AIC induced only relaxation in the rat fundic longitudinal muscle contracted by U46619. PFM showed significantly more effective relaxation compared with PFW, AIM and AIW. Hesperidin, flavonoids known as common constituent of PF and AI and it's an aglycon, hesperetin, induced relaxation in both fundic circular and longitudinal smooth muscle pre-contracted by U46619. Poncirin, known as flavonoid content of PF showed also induced relaxation in the both circular and longitudinal smooth muscle pre-contracted by U46619. These results suggest that both PF and AI has relaxing effects on the gastric fundus smooth muscle and its effects might be caused by their flavonoids constituents.

• 대한의생명과학회지
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• 제15권1호
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• pp.25-29
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• 2009

The changes on the regional distributions and frequencies of somatostatin-immunoreactive (IR) cells in the fundus and pylorus of the stomach of osteoporotic Sprague-Dawley rats induced by ovariectomy were studied by immunohistochemical methods. The experimental animals were divided into two groups, one for non-ovariectomized group (Sham) and the other for ovariectomized group (OVX). Samples were collected from the fundus and pylorus regions at the 10 th week after ovariectomy or sham-operation. Somatostatin-IR cells were observed in both regions of the stomach regardless of ovariectomy. Most of these IR cells in the mucosa of the fundus or pylorus were generally spherical or spindle in shape (open type cell) while cells found in the gastric gland regions were round in shape (close type cell). Significantly lower number (P<0.01) of somatostatin-IR cells were detected in OVX as compared with Sham in the fundus and pylorus. In the present study, the density of somatostatin in the stomach was markedly decreased. Therefore, these changes in density of somatostatin-IR cells detected in this study may support the speculation that the development of gastrointestinal symptoms in osteoporosis such as impairments of calcium and some lipids, frequently encountered in patients with postmenopausal osteoporosis because the changes in gastrointestinal endocrine density would reflect the change in the capacity of producing these hormones and regulating gut motility and digestion.

• Journal of Korean Medical Science
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• 제33권43호
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• pp.239.1-239.12
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• 2018

Background: We described a novel multi-step retinal fundus image reading system for providing high-quality large data for machine learning algorithms, and assessed the grader variability in the large-scale dataset generated with this system. Methods: A 5-step retinal fundus image reading tool was developed that rates image quality, presence of abnormality, findings with location information, diagnoses, and clinical significance. Each image was evaluated by 3 different graders. Agreements among graders for each decision were evaluated. Results: The 234,242 readings of 79,458 images were collected from 55 licensed ophthalmologists during 6 months. The 34,364 images were graded as abnormal by at-least one rater. Of these, all three raters agreed in 46.6% in abnormality, while 69.9% of the images were rated as abnormal by two or more raters. Agreement rate of at-least two raters on a certain finding was 26.7%-65.2%, and complete agreement rate of all-three raters was 5.7%-43.3%. As for diagnoses, agreement of at-least two raters was 35.6%-65.6%, and complete agreement rate was 11.0%-40.0%. Agreement of findings and diagnoses were higher when restricted to images with prior complete agreement on abnormality. Retinal/glaucoma specialists showed higher agreements on findings and diagnoses of their corresponding subspecialties. Conclusion: This novel reading tool for retinal fundus images generated a large-scale dataset with high level of information, which can be utilized in future development of machine learning-based algorithms for automated identification of abnormal conditions and clinical decision supporting system. These results emphasize the importance of addressing grader variability in algorithm developments.