• Title/Summary/Keyword: CT

Search Result 8,757, Processing Time 0.046 seconds

The Influence of Attachment Type on the Distribution of Occlusal Force in Implant Supported Overdentures (하악 임플란트 오버덴쳐에서 어태치먼트 종류에 따른 응력분포)

  • Sung, Chai-Ryun;Cho, In-Ho
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.25 no.4
    • /
    • pp.375-390
    • /
    • 2009
  • Statement of problem: Implant supported overdenture is accepted widely as a way to restore edentulous ridge providing better retention and support of dentures. Various types of attachment for overdenture have been developed. Purpose: The purpose of this study was to investigate the influence of attachment type in implant overdentures on the biomechanical stress distribution in the surrounding bone, prosthesis and interface between implant and bone. Material and methods: Finite element analysis method was used. Average CT image of mandibular body(Digital $Korea^{(R)}$, KISTI, Korea) was used to produce a mandibular model. Overdentures were placed instead of mandibular teeth and 2mm of mucosa was inserted between the overdenture and mandible. Two implants($USII^{(R)}$, Osstem, Korea) were placed at both cuspid area and 4 types of overdenture were fabricated ; ball and socket, Locator, magnet and bar type. Load was applied on the from second premolar to second molar tooth area. 6 times of finite element analyses were performed according to the direction of the force $90^{\circ}$, $45^{\circ}$, $0^{\circ}$ and unilateral or bilateral force applied. The stress at interface between implants and bone, and prosthesis and the bone around implants ware compared using von Mises stress. The results were explained with color coded graphs based on the equivalent stress to distinguish the force distribution pattern and the site of maximum stress concentration. Results: Unilateral loading showed that connection area between implant fixture and bar generated maximum stress in bar type overdentures. Bar type produced 100 Mpa which means the most among 4 types of attachments. Bilateral loading, however, showed that bar type was more stable than other implants(magnet, ball and socket). 26 Mpa of bar type was about a half of other types on overdenture under $90^{\circ}$ bilateral loading. Conclusions: In any directions of stress, bar type was proved to be the most vulnerable type in both implants and overdentures. Interface stress did not show any significant difference in stress distribution pattern.

A Comparative Study of Stenting versus Surgical Bypass in Gastric Outlet Obstruction Caused by Gastric Cancer (위암 날문부 폐쇄 환자에게 시행한 치료의 비교고찰: 위-공장 우회술과 금속성 자가팽창성 스텐트 삽입술)

  • Jo, Seung-Jin;Yoon, Ki-Young;Choi, Kyung-Hyun;Park, Moo-In;Park, Seun-Ja;Ko, Ji-Ho;Lee, Sang-Ho
    • Journal of Gastric Cancer
    • /
    • v.7 no.2
    • /
    • pp.82-87
    • /
    • 2007
  • Purpose: In gastric cancer patients with gastric outlet obstruction, there are several complications such as malnutrition and vomiting. Palliative enteral stenting is a less invasive procedure as compared with a gastrojejunostomy. The aim of this study was to determine whether there was a significant difference between patients that undergone palliative enteral slanting and patients that had received a bypass gastrojejunostomy. Materials and Methods: One hundred patients underwent palliative entering stenting and 3f patients were subjected to a surgical bypass gastrojejunostomy. We reviewed the medical records of the patients with gastric outlet obstruction secondary to far advanced gastric cancer that were diagnosed using a gastrofibroscope, UGI and abdominal CT, and were admitted to our institution between January 2000 and August 2006. The outcome of stent placement for gastric outlet obstruction was compared with palliative gastrojejunostomy during the same period. We excluded patients with recurrent gastric cancer and double cancer from this study. Results: There were significant differences between the group of patients that underwent slanting and the group of patients that received a gastrojejunostomy regarding the age of patients ($67{\pm}12$ vs. $57{\pm}9$, P<0.001) but not between the sex of the patients (M : F, 2 : 1 vs. 2 :1, P=0.637). The most common complication of stenting was tumor ingrowth (16/100, 16%) and the second most common complication was stent migration (14/100). Failure of the procedure occurred in only three patients. Twenty-three patients underwent re-slanting and one patient required open conversion with a gastrojejunostomy. The median time to the first meal was $4{\pm}2$ days in the stent group of patients and $6{\pm}2$ days in the gastrojejunostomy group of patients (P=0.001). The median postoperative hospital stays were 9 days in the stent group of patients and 15 days in the gastrojejunostomy group of patients (P=0.003). The mean survival periods were 11 months in the stent group of patients and 10 months in the gastrojejunostomy group of patients (P=0.937). Conclusion: There were no significant differences In the mean survival rates. An earlier first meal and a shorter hospitalization stay were found in the slanting group of patients compared to the bypass gastrojejunostomy group of patients. However, re-slanting was a concern due to tumor ingrowth and stent migration.

  • PDF

Interleukin-4 and -8 Gene Polymorphisms and Risk of Gastric Cancer in a Population in Southwestern China

  • Pan, Xiong-Fei;Wen, Ying;Loh, Marie;Wen, Yuan-Yuan;Yang, Shu-Juan;Zhao, Zhi-Mei;Tian, Zhi;Huang, He;Lan, Hui;Chen, Feng;Soong, Richie;Yang, Chun-Xia
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.15 no.7
    • /
    • pp.2951-2957
    • /
    • 2014
  • Background: Gastric carcinogenesis is a complicated process that involves environmental and genetic factors like interleukin-4 (IL-4) and IL-8. Single nucleotide polymorphisms in their genes are associated with changed levels of gene expression. Here, we investigated the association between IL4-590 C>T and IL8-251T>A and gastric cancer (GC) risk in Sichuan of Southwestern China. Materials and Methods: We surveyed the research subjects using a self-designed questionnaire with questions on demographic factors and putative risk factors. Approximately 2-5ml of whole blood was collected after field survey to analyze IL4-590 C>T and IL8-251T>A genotypes using MALDI-TOF MS. Results: Our study recruited 308 pairs of GC patients and controls, including 224 (72.7%) men and 84 (27.3%) women in each group. There were 99 cardia and 176 noncardia GC patients in the case group. The case and control groups had an average age of $57.7{\pm}10.6$ ($mean{\pm}SD$) and $57.6{\pm}11.1$ years. GC patients reported a significantly greater proportion of family history of cancer (29.9% vs 10.7%, p<0.01) and drinking (54.6% vs 43.2%, p<0.01) than did controls. Variant genotypes of IL-4-590 C>T and IL-8-251 T>A were not associated with overall GC risk (adjusted OR, 0.89; 95%CI, 0.61-1.28 for CT or CC vs TT; adjusted OR, 1.14; 95%CI, 0.86-1.79 for TA or AA vs TT). Stratification analysis of two SNPs for risk by subsites only found that variant IL-8-251 TA or AA genotype was associated with increased noncardia GC risk (adjusted OR, 2.58; 95%CI, 1.19-5.57). We did not observe interactions between the IL-8-251 T>A genotype and smoking (adjusted OR, 0.38; 95%CI, 0.08-1.79) or drinking (adjusted OR, 0.36; 95%CI, 0.08-1.65) for risk of noncardia GC. Conclusions: Our data indicate no association between the two SNPs of IL-4-590 and IL-8-251 with overall GC risk, while the IL-8-251 TA or AA genotype conferred risk of cardia GC. Our findings contribute to the evidence body for risk of SNPs associated with the development of gastric cancer in this region.

Clinical Utility of Prominent Hypointense Signals in the Draining Veins on Susceptibility-Weighted Imaging in Acute Cerebral Infarct: As a Marker of Penumbra and a Predictor of Prognosis (급성 뇌경색에서 자화율강조영상에서 보이는 현저한 유출정맥 저신호 강도의 임상적 유용성: Penumbra 및 예후 예측인자로서 가능성)

  • Lee, Hyun Sil;Ahn, Kook Jin;Choi, Hyun Seok;Jang, Jin Hee;Jung, So Lyung;Kim, Bum Soo;Yang, Dong Won
    • Investigative Magnetic Resonance Imaging
    • /
    • v.18 no.4
    • /
    • pp.332-340
    • /
    • 2014
  • Purpose : A relative increase in deoxyhemoglobin levels in hypoperfused tissue can cause prominent hypointense signals in the draining veins (PHSV) within areas of impaired perfusion in susceptibility-weighted imaging (SWI). The purpose of this study is to evaluate the usefulness of SWI in patients with acute cerebral infarction by evaluating PHSV within areas of impaired perfusion and to investigate the usefulness of PHSV in predicting prognosis of cerebral infarction. Materials and Methods: In 18 patients with acute cerebral infarction who underwent brain MRI with diffusion-weighted imaging and SWI and follow-up brain MRI or CT, we reviewed the presence and location of the PHSV within and adjacent to areas of cerebral infarction qualitatively and measured the signal intensity difference ratio of PHSVs to contralateral normal appearing cortical veins quantitatively on SWI. The relationship between the presence of the PHSV and the change in the extent of infarction in follow-up images was analyzed. Results: Of the 18 patients, 10 patients showed progression of the infarction, and 8 patients showed little change on follow- up imaging. On SWI, of the 10 patients with progression 9 patients showed peripheral PHSV and the newly developed infarctions corresponded well to area with peripheral PHSV on initial SWI. Only one patient without peripheral PHSV showed progression of the infarct. The patients with infarction progression revealed significantly higher presence of peripheral PHSV (p=0.0001) and higher mean signal intensity difference ratio (p=0.006) comparing to the patients with little change. Conclusion: SWI can demonstrate a peripheral PHSV as a marker of penumbra and with this finding we can predict the prognosis of acute infarction. The signal intensity difference of PHSV to brain tissue on SWI can be used in predicting prognosis of acute cerebral infarction.

How to Reflect Sustainable Development, exemplified by the Equator Principles, in Overseas Investment (해외투자(海外投資)와 지속가능발전 원칙 - 프로젝트 파이낸스의 적도원칙(赤道原則)을 중심으로 -)

  • Park, Whon-Il
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
    • /
    • v.31
    • /
    • pp.27-56
    • /
    • 2006
  • Today's financial institutions usually take environmental issues seriously into consideration as they could not evade lender liability in an increasing number of cases. On the international scene, a brand-new concept of the "Equator Principles" in the New Millenium has driven more and more international banks to adopt these Principles in project financing. Sustainable development has been a key word in understanding new trends of the governments, financial institutions, corporations and civic groups in the 21st century. The Equator Principles are a set of voluntary environmental and social guidelines for sustainable finance. These Principles commit bank officers to avoid financial support to projects that fail to meet these guidelines. The Principles were conceived in 2002 on an initiative of the International Finance Corporation(IFC), and launched in June 2003. Since then, dozens of major banks, accounting for up to 80 percent of project loan market, have adopted the Principles. Accordingly, the Principles have become the de facto standard for all banks and investors on how to deal with potential social and environmental issues of projects to be financed. Compliance with the Equator Principles facilitates for endorsing banks to participate in the syndicated loan and help them to manage the risks associated with large-scale projects. The Equator Principles call for financial institutions to provide loans to projects under the following circumstances: - The risk of the project is categorized in accordance with internal guidelines based upon the environmental and social screening criteria of the IFC. - For Category A and B projects, borrowers or sponsors are required to conduct a Social and Environmental Assessment, the preparation of which must meet certain requirements and satisfactorily address key social and environmental issues. - The Social and Environmental Assessment report should address baseline social and environmental conditions, requirements under host country laws and regulations, sustainable development, and, as appropriate, IFC's Environmental, Health and Safety Guidelines, etc. - Based on the Social and Environmental Assessment, Equator banks then make agreements with borrowers on how they mitigate, monitor and manage the risks through a Social and Environmental Management System. Compliance with the plan is included in the covenant clause of loan agreements. If the borrower doesn't comply with the agreed terms, the bank will take corrective actions. The Equator Principles are not a mere declaration of cautious banks but a full commitment of lenders. A violation of the Principles in the process of project financing, which led to an unexpected damage to the affected community, would not give rise to any specific legal remedies other than ordinary lawsuits. So it is more effective for banks to ensure consistent implementation of the Principles and to have them take responsible measures to solve social and environmental issues. Public interests have recently mounted up with respect to environmental issues on the occasion of the Supreme Court's decision (2006Du330) on the fiercely debated reclamation project at Saemangeum. The majority Justices said that the expected environmental damages like probable pollution of water and soil were not believed so serious and that the Administration should continue to implement the project seeking ways to make it more environment friendly. In this case, though the Category A Saemangeum Project was carried out by a government agency, the Supreme Court behaved itself as a signal giver to approve or stop the environment-related project like an Equator bank in project financing. At present, there is no Equator bank in Korea in contrast to three big banks in Japan. Also Korean contractors, which are aggressively bidding for Category A-type projects in South East Asia and Mideast, might find themselves in a disadvantageous position because they are generally ignorant of the environmental assessment associated with project financing. In this regard, Korean banks and overseas project contractors should care for the revised Equator Principles and the latest developments in project financing more seriously. It's because its scope has expanded to the capital cost of US$10 million or more across all industry sectors regardless of developing countries or not. It should be noted that, for a Korean bank, being an Equator bank is more or less burdensome in a short-term period, but it must be conducive to minimizing risks and building up good reputation in the long run.

  • PDF

Serum Carbohydrate Antigen 19-9 as an Indicator of Liver Metastasis in Colorectal Carcinoma Cases

  • Dong, Hang;Tang, Jie;Li, Long-Hao;Ge, Jun;Chen, Xin;Ding, Jing;Men, Hai-Tao;Luo, Wu-Xia;Du, Yang;Li, Cong;Zhao, Feng;Chen, Ye;Cheng, Ke;Liu, Ji-Yan
    • Asian Pacific Journal of Cancer Prevention
    • /
    • v.14 no.2
    • /
    • pp.909-913
    • /
    • 2013
  • Purpose: The liver is the organ to which colorectal carcinomas (CRCs) most commonly metastasize, and surgical resection has been established as the most effective and potentially curative treatment for CRC with liver metastasis (LM). Therefore, surveillance of LM is vital for improvement of prognosis of CRC patients. In this study, we aimed to explore the potential value of carbohydrate antigen 19-9 (CA 19-9), carcinoembryonic antigen (CEA), and marker enzymes in indicating LM with CRC. Methods: Three groups of eligible patients with metastatic cancers were retrospectively included: CRC patients with LM (CRC-LM) or without LM (CRC-NLM), and non-CRC patients with LM (NCRC-LM). All metastatic lesions were identified by CT or MRI. Data on characteristics of the patients, the primary site, the locations of metastasis, CA 19-9, CEA, and biochemical parameters were collected for analysis. Results: A total of 493 patients were retrospectively included. More alcohol consumption was found in CRC-LM than CRC-NLM. Some biochemical enzymes were found to be significantly higher in groups with LM than without (CRC-LM or NCRC-LM v.s CRC-NLM). Both CEA and CA 19-9 were much higher in CRC-LM than CRC-NLM or NCRC-LM. For CRC patients, CA 19-9, ${\gamma}$-glutamyl transpeptidase, CEA and alcohol consumption were identified as independent factors associated with LM. Conclusion: Our analysis suggested the CA 19-9 might be a potential valuable indicator for LM of CRC in the clinic.

Stress Patterns in the Reconstructed Double Bundles of the Anterior Cruciate Ligament in Response to an Anterior Tibial Load and Rotatory Load: an Analysis using a 3-Dimensional Finite Element Model (삼차원 유한 요소 모델을 이용한 전방십자인대 이중다발 재건술 후 전방 전위 및 회전 부하에 따른 이식건 응력 양상 분석)

  • Seo, Young-Jin;Song, Si Young;Ahn, Jung Tae;Kim, Yoon-Sang;Ko, Jun Ho;Jang, Seong-Wook;Yoo, Yon-Sik
    • Journal of the Korean Arthroscopy Society
    • /
    • v.16 no.2
    • /
    • pp.160-166
    • /
    • 2012
  • Purpose: The aim of this study was to determine the patterns of the stress distribution within the reconstructed anterior cruciate ligament (ACL) double bundles in response to an anterior tibial load and rotatory load at $45^{\circ}$ flexed knee model by use of a 3-dimensional finite element analysis (FEM). Materials and Methods: The $0^{\circ}$ and $45^{\circ}$ flexed 3-D knee model were reconstructed based on the high resolution computed tomography (CT) images from the right knee of a healthy male subject. To simulate double bundle ACL reconstruction, in $0^{\circ}$ analytic model, four 7 mm diameter tunnels were created at the center of each anteromedial (AM) and posterolateral (PL) footprints on the femur and tibia. The grafts were inserted into the corresponding bone tunnels and then reconstructed knee model was flexed to $45^{\circ}$. As a next step, the 5 mm anterior tibial load and internal rotational load of $10^{\circ}$ were applied on the final Computer aided design (CAD) model. And then stress patterns of each bundle were assessed using a finite element analysis. Results: In response to the 5 mm of anterior tibial load, the AM bundle showed increased stresses around the tibial and femoral attachment sites; especially in the anterior aspect of the bundle. In the PL bundle, the highest stress concentration was also noticed on the anterior aspect of the bundle. Under $10^{\circ}$ internal rotational load, the stress concentration was predominant around the anterior aspect of the tibial attachment site within the AM bundle. The PL bundle also showed highest stress concentration on the anterior aspect of the bundle. Conclusion: Although the stress patterns were not identical among the AM and PL bundle, there were common trends in the stress distribution. The stress concentration was predominant on the anterior aspect of both bundles in response to the anterior tibial load and rotatory load.

  • PDF

The Effect of Antifibrinolytic Therapy in Prevention of Rebleeding before Early Aneurysm Surgery (뇌동맥류의 조기수술 전 재출혈 방지를 위한 항섬유소용해제 투여의 효과)

  • Lee, Chang Young;Yim, Man Bin;Lee, Jang Chull;Son, Eun Ik;Kim, Dong Won;Kim, In Hong
    • Journal of Korean Neurosurgical Society
    • /
    • v.30 no.9
    • /
    • pp.1065-1071
    • /
    • 2001
  • Object : This study was conducted to evaluate whether short-term intravenous infusion of tranexamic acid (AMCA) was able to improve the management outcome by preventing rebleeding without increasing vasospasm and hydrocephalus associated with the long-term administration of this agent in the patients with aneurysmal subarachnoid hemorrhage(SAH) who were planned for the early surgery. Methods : During the period from June, 1996 to May, 1998, 137 patients admitted within 3 days of their SAH and planned for early surgical intervention were subject to study population. Of these, 60 patients who had been treated with AMCA were classified as AMCA treated group and 77 patients without AMCA treatment as AMCA untreated group. Initially, prognostic factors for rebleeding, vasospasm, hydrocephalus and outcome following SAH including age, sex, clinical grade, CT grade, site of ruptured aneurysms, admission day after SAH, surgery day after SAH, number of aneurysms and hypertension history, were analyzed and compared between AMCA treated group and untreated group. Secondly, the incidence of rebleeding, symptomatic vasospasm and hydrocephalus were compared between the two groups. Also, the management outcome of the patients was compared between the two groups. Results : There were no significant differences in prognostic factors between the two groups. The rebleeding rate was 0% in the AMCA treated group whereas the rate was 7.8% in the untreated group. This difference was statistically significant. The incidences of symptomatic vasospasm and hydrocephalus were found not to be significantly different between the two groups. Of the treated group, 31.7% of patients developed hydrocephalus compared to 32.5% of those at the untreated group. Fourteen(23.3%) patients in treated group developed symptomatic vasospasm and 6 of them(10%) suffered stroke whereas incidences of these in untreated group were 25.9% and 11.7%, respectively. The AMCA treated group showed more favorable outcome than that of untreated group. There was no case of death by rebleeding in the AMCA treated group while one of the main causes of death in the untreated group was rebleeding. Conclusion : Short-term high-dose AMCA administration is considered beneficial in improving outcome and diminishing the risk of rebleeding in the patients who suffer from an aneurysmal SAH prior to early surgical intervention.

  • PDF

A Pressure Adjustment Protocol for Programmable Valves

  • Kim, Kyoung-Hun;Yeo, In-Seoung;Yi, Jin-Seok;Lee, Hyung-Jin;Yang, Ji-Ho;Lee, Il-Woo
    • Journal of Korean Neurosurgical Society
    • /
    • v.46 no.4
    • /
    • pp.370-377
    • /
    • 2009
  • Objective : There is no definite adjustment protocol for patients shunted with programmable valves. Therefore, we attempted to find an appropriate method to adjust the valve, initial valve-opening pressure, adjustment scale, adjustment time interval, and final valve-opening pressure of a programmable valve. Methods : Seventy patients with hydrocephalus of various etiologies were shunted with programmable shunting devices (Micro Valve with $RICKHAM^{(R)}$ Reservoir). The most common initial diseases were subarachnoid hemorrhage (SAH) and head trauma. Sixty-six patients had a communicating type of hydrocephalus, and 4 had an obstructive type of hydrocephalus. Fifty-one patients had normal pressure-type hydrocephalus and 19 patients had high pressure-type hydrocephalus. We set the initial valve pressure to $10-30\;mmH_2O$, which is lower than the preoperative lumbar tapping pressure or the intraoperative ventricular tapping pressure, conducted brain computerized tomographic (CT) scans every 2 to 3 weeks, correlated results with clinical symptoms, and reset valve-opening pressures. Results : Initial valve-opening pressures varied from 30 to $180\;mmH_2O$ (mean, $102{\pm}27.5\;mmH_2O$). In high pressure-type hydrocephalus patients, we have set the initial valve-opening pressure from 100 to $180\;mmH_2O$. We decreased the valve-opening pressure $20-30\;mmH_2O$ at every 2- or 3-week interval, until hydrocephalus-related symptoms improved and the size of the ventricle was normalized. There were 154 adjustments in 81 operations (mean, 1.9 times). In 19 high pressure-type patients, final valve-opening pressures were $30-160\;mmH_2O$, and 16 (84%) patients' symptoms had nearly improved completely. However, in 51 normal pressure-type patients, only 31 (61%) had improved. Surprisingly, in 22 of the 31 normal pressure-type improved patients, final valve-opening pressures were $30\;mmH_2O$ (16 patients) and $40\;mmH_2O$ (6 patients). Furthermore, when final valve-opening pressures were adjusted to $30\;mmH_2O$, 14 patients symptom was improved just at the point. There were 18 (22%) major complications : 7 subdural hygroma, 6 shunt obstructions, and 5 shunt infections. Conclusion : In normal pressure-type hydrocephalus, most patients improved when the final valve-opening pressure was $30\;mmH_2O$. We suggest that all normal pressure-type hydrocephalus patients be shunted with programmable valves, and their initial valve-opening pressures set to $10-30\;mmH_2O$ below their preoperative cerebrospinal fluid (CSF) pressures. If final valve-opening pressures are lowered in 20 or $30\;mmH_2O$ scale at 2- or 3-week intervals, reaching a final pressure of $30\;mmH_2O$, we believe that there is a low risk of overdrainage syndromes.

Acquisition of High Resolution Images and its Application using Synchrotron Radiation Imaging System (방사광 X-선을 이용한 고해상도 영상획득과 응용)

  • 홍순일;김희중;정해조;홍진오;정하규;김동욱;제정호;김보라;유형식
    • Progress in Medical Physics
    • /
    • v.12 no.1
    • /
    • pp.51-58
    • /
    • 2001
  • Synchrotron radiation (SR) has several advantages over convetional x-rays, including its phase, collimation, and high flux. A synchrotron radiation beamline 5C1 at Pohang Light Source (PLS) was recently built for imaging applications. We have shown that a SR imaging system is useful in imaging microscopic structures. SR with broad-band energy spectrum were adjusted to an object by Si wafers and their energy were approximately ranging from 6 keV to 30 keV. SR were passed through an object and finally transformed into visible lights by CdWO$_4$ scintillator screen. The visible lights which were reflected at an angle of 90 degrees by gold plated mirror were detected by a CCD camera and the image data were acquired using image acquisition system. A high-resolution phantom, capacitor, adult tooth, child tooth, cancerous breast tissue, and mouse lumbar vertebra were imaged with SR imaging system. The Objects were rotated within the field of view of the CCD detector, and their projection image data were obtained at 250 steps over 180 degrees rotation. Image reconstructions were carried out in a PC by using IDLTM(Research systems, Inc., US) program. The spatial resolution of the images acquired by the SR imaging system was measured with a high-resolution chart manufactured for several micrometer resolution. The specimens were also imaged with conventional x-ray radiography system to compare the image quality of radiography obtained with the SR imaging system. The results showed more structural details and high contrast images with SR imaging system than conventional x-ray radiography system. The SR imaging system may have a potential for imaging in biological researches, material applications, and clinical radiography.

  • PDF