• Title/Summary/Keyword: recovery center

Search Result 1,869, Processing Time 0.04 seconds

Analysis and Improvement Strategies for Korea's Cyber Security Systems Regulations and Policies

  • Park, Dong-Kyun;Cho, Sung-Je;Soung, Jea-Hyen
    • Korean Security Journal
    • /
    • no.18
    • /
    • pp.169-190
    • /
    • 2009
  • Today, the rapid advance of scientific technologies has brought about fundamental changes to the types and levels of terrorism while the war against the world more than one thousand small and big terrorists and crime organizations has already begun. A method highly likely to be employed by terrorist groups that are using 21st Century state of the art technology is cyber terrorism. In many instances, things that you could only imagine in reality could be made possible in the cyber space. An easy example would be to randomly alter a letter in the blood type of a terrorism subject in the health care data system, which could inflict harm to subjects and impact the overturning of the opponent's system or regime. The CIH Virus Crisis which occurred on April 26, 1999 had significant implications in various aspects. A virus program made of just a few lines by Taiwanese college students without any specific objective ended up spreading widely throughout the Internet, causing damage to 30,000 PCs in Korea and over 2 billion won in monetary damages in repairs and data recovery. Despite of such risks of cyber terrorism, a great number of Korean sites are employing loose security measures. In fact, there are many cases where a company with millions of subscribers has very slackened security systems. A nationwide preparation for cyber terrorism is called for. In this context, this research will analyze the current status of Korea's cyber security systems and its laws from a policy perspective, and move on to propose improvement strategies. This research suggests the following solutions. First, the National Cyber Security Management Act should be passed to have its effectiveness as the national cyber security management regulation. With the Act's establishment, a more efficient and proactive response to cyber security management will be made possible within a nationwide cyber security framework, and define its relationship with other related laws. The newly passed National Cyber Security Management Act will eliminate inefficiencies that are caused by functional redundancies dispersed across individual sectors in current legislation. Second, to ensure efficient nationwide cyber security management, national cyber security standards and models should be proposed; while at the same time a national cyber security management organizational structure should be established to implement national cyber security policies at each government-agencies and social-components. The National Cyber Security Center must serve as the comprehensive collection, analysis and processing point for national cyber crisis related information, oversee each government agency, and build collaborative relations with the private sector. Also, national and comprehensive response system in which both the private and public sectors participate should be set up, for advance detection and prevention of cyber crisis risks and for a consolidated and timely response using national resources in times of crisis.

  • PDF

Analysis of volatile compounds and metals in essential oil and solvent extracts of Amomi Fructus (사인으로부터 추출한 정유와 용매 추출물의 휘발성 물질 및 금속성분 분석)

  • Lee, Sam-Keun;Eum, Chul Hun;Son, Chang-Gue
    • Analytical Science and Technology
    • /
    • v.28 no.6
    • /
    • pp.436-445
    • /
    • 2015
  • Amomi Fructus with anti-oxidative activity was chosen and essential oil was obtained by SDE (simultaneous distillation extraction), and 39 constituents were determined by GC-MS (gas chromatography-mass spectrometry). Major components were camphor, borneol acetate, borneol, D-limonene and camphene. Three solvent extracts such as hexanes, diethyl ether and methylene chloride from Amomi Fructus were obtained. These were analyzed by GC-MS and 4 more constituents were identified in addition to 39 components discovered in essential oil. Five major components such as camphor, borneol acetate, borneol, D-limonene and camphene were also detected, however the relative peak percents of those components were different from those of constituents in essential oil. To estimate the kind and the amount of materials evaporated at certain temperature and conditions from essential oil and solvent extracts, dynamic headspace apparatus was used and materials evaporated and trapped at certain conditions were analyzed by GC-MS. Recovery yield of SDE method from Amomi Fructus was measured by using camphor and standard calibration solution of camphor methanol solution and, the yield was 82.0%. Content of Hg was measured by mercury analyzer and contents of Cd, Pb, Cr, Mn, Co, Ni, Cu and Zn in Amomi Fructus, essential oils and solvent extracts were determined by ICP-MS (Inductively coupled plasma-mass spectrometer). Pb, Cd and Hg were measured in the concentration of 0.72 mg/kg, <0.10 mg/kg and 0.0023 mg/kg, respectively and these were below permission level of purity test. Contents of Mn, Cu and Zn in Amomi Fructus were 213 mg/kg, 8.29 mg/kg and 31.0 mg/kg, respectively and which were relatively higher than other metals such as Cr, Co and Ni. Metals such as Mn (0.65 ~ 9.08 mg/kg), Cu (1.16 ~ 4.40 mg/kg) and Zn (1.10 ~ 3.80 mg/kg) in essential oil and solvent extracts were detected. At this point it is not clear that the metals were cross-contaminated in the course of treating Amomi Fructus or metals were contained in Amomi Fructus. The influence evaluation toward biological model study of these metals in essential oil and solvent extracts will be needed.

Changes of Ventricular Function and Mitral Regurgitation after Repair of Anomalous Origin of Coronary Artery from the Pulmonary Artery (관상동맥 폐동맥 이상 기시증의 외과적 치료 후 좌심실 및 승모판 기능의 변화)

  • Lee Jeong Ryul;Oh Sea Jin;Kim Woong Han;Kim Yong Jin;Rho Joon Ryang;Bae Eun Jung;Noh Chung II;Yun Yong Soo
    • Journal of Chest Surgery
    • /
    • v.38 no.8 s.253
    • /
    • pp.523-528
    • /
    • 2005
  • Background: Investigation of the change of ventricular function and mitral regurgitation after surgical repair of patient with anomalous origin of left coronary artery from the pulmonary artery (ALCAPA) is key issue for the better surgical outcome. Material and Method: From April 1986 to July 2002, 12 patients presented with ALCAPA. The median age at repair was 4 months. Surgical methods included left coronary artery transfer to the aorta (10), Takeuchi procedure (1), saphenous vein free graft bypass (1). Mitral valve was repaired in 1. Result: There were 2 hospital death $(16.7\%)$. The mean follow-up period was $7.1\pm4.1$ years (range, 7 months to 13 years). Four patients required postoperative circulatory assist for $2.2\pm1.1$ days and one needed left ventricular assist device (LVAD) for 1day. Postoperative echocardiography demonstrated significant improvements in mean fractional shortening $(33.4\pm9.1\%\;vs\;17.7\pm9.6\%,\;n=10,\;p<0.05);$ left ventricular end diastolic dimension $(33.4\pm7.3\;mm\;vs\;44.8\pm7.0\;mm,\;n=10,\;p<0.05)$ and systolic dimension $(22.2\pm7.5\;mm\;vs\;33.4\pm7.9\;mm,\;n=10,\;p<0.05)$. Severities of mitral regurgitation decreased in all survivors at 1st and 4th year follow-up echocardiography. There were 2 reoperation due to residual MR and right ventricular outflow obstruction (Takeuchi case). Conclusion: Anatomic repair of anomalous left coronary artery from the pulmonary artery offered an excellent surgical results, especially in terms of the recovery of left ventricle function and mitral regurgitation. However, preoperative indications for mitral procedure is to be evaluated.

A Study of Relation Between Dietary Vitamin A Intake and Serum Vitamin A Levels and Cancer Risk in Korea (한국인의 식이섭취와 암 유발의 관계에 관한 연구 -제 1 보 특히 ${\beta}-Carotene$ 섭취량과 혈청내 수준을 중심으로 -)

  • Lee, Ki-Yull;Lee(Kim), Yang-Cha;Park, Young-Sim;Yoon, Kyo-Hee;Kim, Byung-Soo
    • Journal of Nutrition and Health
    • /
    • v.18 no.4
    • /
    • pp.301-311
    • /
    • 1985
  • Even though the anticarcinogenic effect of dietary factors especially beta - carotene has been reported by various investigators, the mechanism of the action of ${\beta}-carotene$ has not yet been identified. We carried out the present study to determine the possibilities of relative cancer risk related to dietary intake of vitamin A ( both ${\beta}-carotene$ and retinol ) and blood levels of vitamin A among Koreans. The subjects were divided into two groups; cancer patients and controls. Blood levels for ${\beta}-carotene$ and retinol were analyzed by alumina column chromatography and colorimetry. Dietary intake was examined by food profile and convenient method for evaluating nutritional status through recalling 10 years of food habits. The results obtained are as follows : 1 ) Calorie, protein, fat, and carbohydrate intakes of cancer patient were lower than those of control. Calorie and carbohydrate intakes showed no significant difference but protein and fat intakes were significantly lower in cancer patients. According to cancer sites, in stomach cancer only fat intake was significantly lower than that of control. In lung and larynx cancer calorie, protein, fat and carbohydrate intakes showed similar trend as in control. 2 ) Vitamin A intake of cancer patient was significantly lower than that of control. It was estimated that 83.6% of total Vitamin A intake were provided by ${\beta}-carotene$ for control and cancer patient respectively. 3 ) The mean intake of dietary ${\beta}-carotene$ in cancer patient was significantly lower than that in control ( $7002\;\mu}g/day$ versus $10326\;{\mu}g/day$ ) According to cancer sites in mean intake of dietary ${\beta}-carotene$ was significantly lower in all but stomach cancer compared with that of control. Lung and larynx cancer showed lowest ${\beta}-carotene$ intake with mean value of $5855{\mu}g/day$ and $5492{\mu}g/day$ respectively. 4 ) The mean intake of dietary retinol in cancer patient was significantly lower than that in control ( $245{\mu}g/day$ versus $338{\mu}g/day$ ), but the difference was not significant. 5 ) The relative risk of all cancers in the first (lowest) to the forth quartile level of ${\beta}-carotene$ consumption such as $0-5999{\mu}g/day$. $6000-8999{\mu}g/day$, $9000-11999{\mu}g/day$/ day and $12000-20000{\mu}g/day$ was 85 : 1.7 : 20 : 1.0. The relative risk of all cancers in the first (lowest) to the forth quartile level of retinol consumption, such as $0-299{\mu}g/day$, $300-599{\mu}g/day$, 600-899${\mu}g/day$, and $900-1200{\mu}g/day$, was 1.14 : 067 : 0.21 : 1.0. 6 ) The various food group consumption of cancer patient were significantly lower than those of control in green leafy vegetables, fruits, sea weeds, milk and cheese and eggs. But the Kimchie consumption in cancer patient was three fold higher than that of control ( $1840\;{\mu}g/day$ versus $562\;{\mu}g/day$ ) and in the stomach cancer, Kimchie consumption was the highest, ( $1890\;{\mu}g/day$) According to cancer sites, the consumption of green leafy vegetables was significantly lower in all but stomach cancer compared to control and other vegetables showed no difference between two. In lung and larynx cancer, green leafy vegetables consumption was lowest ( $6094{\mu}g/day$ $5921{\mu}g/day$) and milk and cheese consumption was also( $5\;{\mu}g/day$ and $11{\mu}g/day$) 7 ) The recovery of ${\beta}-carotene$ from human serum by alumina column chromatography was $94.4{\pm}2.3%$. 8 ) Cancer patients showed significantly lower serum retinol ($56.4{\pm}18.1\:{\mu}g/100ml$ versus $72.2{\pm}21.8\:{\mu}g/100ml$) and ${\beta}-carotene$ ($48.9{\pm}33.8\:{\mu}g/100ml$ versus $72.2{\pm}42.6\:{\mu}g/100ml$) concentrations than in controls. 9 ) But breast cancer patients were not significantly different from controls in their serum retinol and ${\beta}-carotene$ concentrations.

  • PDF

A Study on Satisfaction level with Herbal Public Health Services and its Improvement Plans (한방공중보건서비스 만족도와 개선방안)

  • Lee, Jae-Won;Koo, Jin-Suk;Seo, Bu-Il
    • Korean Journal of Oriental Medicine
    • /
    • v.18 no.2
    • /
    • pp.65-89
    • /
    • 2012
  • Objective : In order to investigate and improve public Korean medical health service satisfaction level, this study was designed. Method : A questionnaire has been conducted on 212 patients who received treatments at six public health centers in the northern part of Gyeongbuk during 15 days between Sep. 24 and Oct. 8, 2011. Result : 1. An Investigation on the usage of herbal clinics in public health centers reveals that 63.7% have received three times or more medical treatments previously and 61.8% have had their illness treated at other medical institutions. In regard to illness 32.1% have had arthritis or muscle aches. 50.9% have taken insurance medication after having had treatments at the public health centers. 66% have assessed acupuncture and moxa cautery the most satisfying. 2. To a question regarding whether herbal health treatment costs higher than that of physician's, the highest response at 31.6% is 'No'. And to a question regarding whether herbal medicines administered at public health centers have more side effects than that of physician's, the highest response at 39.6% is 'No'. 3. To a question regarding whether herbal treatment of public health centers has little effect against acute disease, 48.1% of responses are 'Fair'. To a question regarding whether herbal treatments, when compared with physician's treatments, boost better recovery of patients, 48.1% of responses are 'Fair'. To a question regarding whether herbal medicine is unscientific, when compared with that of western medicine, 38.2% of responses are 'Fair', To a question regarding whether herbal medicine has faster effect on disease than western medicine, 41.0% of responses are 'Fair'. To a question regarding whether herbal medicine is more effective on disease prevention and promotion of health than disease treatment, 38.2% of responses are 'Fair'. And to a question regarding whether the lack of various types of physical therapy devices in herbal medicine, when compared with western medicine causes inconvenience in herbal treatment, 42.0% of responses are 'Fair'. Those responses take up highest portion at each questionnaire. 4. A comparative study between herbal treatments and physician's treatments has also been conducted. To questions regarding which one of the two considering types of disease is the better, responses are the latter accounted for 43.9% against 'Cancer', the latter accounted for 45.3% against 'Endocrine disorders', the former accounted for 30.7% against 'Psychiatric disorders', the latter accounted for 38.2% gainst 'Otolaryngological(ENT) disease', the former accounted for 47.6% against 'Post traumatic stress disorder', and the former accounted for 52.4% against 'Muscle-skeletal disease'. 5. An investigation on frequency of patients' visits via (p<0.05) of subjects show a statistically significant difference. 6. First, an investigation on frequency of reasons of medical treatments reveal that age, occupation, monthly income, and insurance type (p<0.05) of subjects show a statistically significant difference. Secondly, an investigation on frequency of subjects taking insurance medicines after herbal health treatments reveal that monthly income (p<0.05) of subject shows a statistically significant difference. 7. First, an investigation on frequency of a claim that herbal treatments of public health center does not have great effect on acute disease reveals that age, education, and insurance type (p<0.05) of subjects show a statistically significant difference. Secondly, an investigation on frequency of analysis that herbal treatments has faster effect on disease compared with western treatments reveals that education level, religion, monthly income, and insurance type (p<0.05) of subjects show a statistically significant difference. 8. When herbal clinics of public health centers and general herbal medicine institutions are compared, a survey on additional treatments that herbal clinics need the most reveals that education level, monthly income, and insurance type (p<0.05) of subjects show a statistically significant difference. Secondly, an investigation on frequency of subjects who want various forms of herbal medicines reveals that occupation and insurance type (p<0.05) of subjects show a statistically significant difference. Conclusion : In order to improve efficiency of treatments and enhance patient's satisfaction level, this study suggests measures such as providing a differentiated acupuncture treatments as a whole, streamlining an reception procedure, adopting more elaborated computer system for a patient to get proper medical attention, standardizing a treatment duration in order for a maximum result, keeping regular office hours, and optimizing a consultation time for a patient.

Naturally Collection and Development until Yolk Absorption of Domestic Walleye Pollock Theragra chalcogramma Fertilized Eggs and Larvae (국내 명태 Theragra chalcogramma 자연채란과 난황흡수까지의 난 발생)

  • Seo, Joo-young;Kwon, O-Nam
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.18 no.1
    • /
    • pp.49-54
    • /
    • 2017
  • We collected and reared Theragra chalcogramma walleye pollock brood-stock for use in natural spawning tests and undertook to obtain domestic pollock via fertilized egg capture, development of fertilized eggs, and absorption of yolk sac after hatching. Whole pollock were caught with trammel and set nets and immediately placed in a deep-sea water tank. Adults were the most common pollock age group (43.0%; n = 86) among the 254 pollock captured in March 2014 with 57.9% (n = 147) being captured off Southern Gosung, Korea. The main spawning period of pollock is February (spawning phase of 91% of pollock). From the deep-sea tank, we collected 1640 mL of naturally fertilized eggs (~820,000 eggs) from 12 spawning events occurring between February 4 and 22 2015. The floating/ live eggs were maintained in deep-sea water tanks at $5.5{\pm}0.2^{\circ}C$. Egg size was $1.5{\pm}0.03mm$. Six hours after fertilization the eggs were at the 2 cell stage, and the eggs hatched approximately 340 hours after collection. At hatching, larval length and yolk sac area were $5.2{\pm}0.25mm$ and $9.5{\pm}1.00mm^2$ (100%), respectively. Four days after hatching, the yolk sac area was $2.2{\pm}0.53mm^2$ ($23.1{\pm}5.55%$). This is the first report of collection of naturally fertilized eggs from pollock and their subsequent hatching while held in an indoor deep-sea water tank. The results suggest that such collection could assist in the recovery of pollock resources and the possibility of domestic rearing of cultivated larvae.

The Effect of Inositol and Phytic Acid on Skin (이노시톨과 피틴산이 피부에 미치는 영향)

  • Zho Choon Koo;Han Chang Giu;Song Hwan
    • Journal of the Society of Cosmetic Scientists of Korea
    • /
    • v.30 no.4 s.48
    • /
    • pp.515-524
    • /
    • 2004
  • Inositol and phytic acid extracted from rice bran were investigated for applying cosmetics. Skin lotions containing $0{\~}3.0\;wt\%$ inositol and $0{\~}1.50\;wt%$ phytic acid were applied respectively, to the arm skins of 45 Asian women 20'~40's for 7 weeks. Improvement on moisture was evaluated. In addition, improvements on sebum, elasticity, and wrinkle were examined after applying placebo, inositol and phytic acid-containing skin lotions tot face, respectively. For $1.0\;wt\%$ inositol, it resulted in $19\%$ increase of moisture. The wrinkle reduction and elasticity improved $12.4%\;and\;17.0\%$ on average, respec-tively. Applying $0.5\;wt\%$ phytic acid resulted in $71.6\%$ increase the moisture. Improvements on wrinkle and elasticity were $16.9%\;and\;21.9\%$ respectivelv. hpplving inositol or phytic acid regardless of dry or oily skin, resulted in sebum value recovery to that of the normal skin after 2~4 weeks. Although inositol is inferior to phytic acid in improvements of the skin, phytic acid is not suitable to sensitive skin. So, $0~0.50\;wt\%$ of phytic acid were added to $1.0\;wt\%$ inositol and similar experiments were carried out. In case of added $1.0\;wt\%$ phytic acid, moisture increased $63.8\%$ approximately. Improvements on elasticity and reduction on wrinkle were $17.2%\;and\;17.4\%,$ respectively. Both skin types were turned to normal skin type after 2 weeks. It could improve the skin condition when used inositol added phytic acid. The optimized concentration of phytic acid was $0.10\;wt\%\;with\;1.0\;wt\%$ of inositol without side effect.

Effect of fermented Hovenia dulcis Thunb fruit water extract on biomarker for liver injury and body weight changes in rats given oral administration of ethanol (헛개열매추출액발효물이 흰쥐의 에탄올 경구투여에 의한 간손상 지표와 체중 감량 완화에 미치는 영향)

  • Choi, Ji-Young;Kim, Jun-Han;Kim, Gho;Kim, Choon-Kyung;Choi, Myung-Sook
    • Food Science and Preservation
    • /
    • v.21 no.3
    • /
    • pp.412-420
    • /
    • 2014
  • This study was performed to investigate the effect of fermented Hovenia dulcis Thunb fruit water extract on biomarkers for acute (a) ethanol-induced hangover and chronic (c) ethanol-induced liver injury in rats. For acute ethanol-induced hangover, the rats were administered distilled water (D.W., 10 mL/kg body wt.), Hovenia dulcis Thunb fruit water extract (HWE, 400 mg/10 mL/kg body wt.) and fermented HWE (FHWE, 400 mg/10 mL/kg body wt.), respectively, before 40% ethanol (5 g/kg body wt.) was administered. For chronic ethanol-induced liver injury, the rats were randomly divided into the normal control (cNC), ethanol (cET), cET-HWE and cET-FHWE groups. The cNC and cET groups were administered D.W. (10 mL/kg body wt.) before 40% alcohol (5 g/kg body wt.) was administrered for 21 days. The cET-HWE and cET-FHWE groups were administered HWE (400 mg/10 mL/kg body wt.) and FHWE (400 mg/10 mL/kg body wt.), respectively before 40% ethanol (5 g/kg body wt.) administration for 21 days. For acute ethanol-induced hangover, the serum alcohol and acetaldehyde concentrations were more significantly reduced in the aHWE and aFHWE groups than in the aET group. Moreover, the effect of FHWE was greater than that of HWE. For chronic ethanol-induced liver injury, the serum ethanol, acetaldehyde, ${\gamma}$-glutamyl transpeptidase (${\gamma}$-GTP) levels and the hepatic lipids concentration more significantly dropped in the cET-HWE and cET-FHWE groups than in the cET group. The FHWE administration showed faster recovery of the serum glucose concentration than in the cET and cET-HWE groups. The body weight reduction tended to normalize in the cET-HWE and cET-FHWE groups, which is ideal for chronic ethanol administration. These results suggest that FHWE has a protective effect against ethanol-induced liver damage, as evidenced by its ability to lower the serum ethanol and acetaldehyde concentrations after alcohol administration, and by its ability to decrease the level of ${\gamma}$-GTP and hepatic lipids. FHWE also elevated serum glucose concentration. Therefore, FHWE is effective in reducing ethanol-induced hangover and can play a beneficial role in the treatment of ethanol-induced liver damage as well as body weight reduction.

Evaluation of Antidepressant Drug Effect in a Depressive Animal Model by Proton MR Spectroscopy (양성자 자기공명분광법을 이용한 우울증 동물모델에서의 항우울제 약물 효능 평가)

  • Kim, Sang-Young;Choi, Chi-Bong;Lee, Sung-Ho;Woo, Dong-Cheol;Yoon, Seong-Ik;Hong, Kwan-Soo;Lee, Hyun-Sung;Cheong, Chae-Joon;Jee, Bo-Keun;Hong, Sung-Tak;Kim, Hwi-Yool;Choe, Bo-Young
    • Progress in Medical Physics
    • /
    • v.19 no.2
    • /
    • pp.95-101
    • /
    • 2008
  • In this study, we observed the alteration of choline signal intensity in hippocampus region of the depressive rat model induced by forced swimming test (FST). The purpose of this study was to evaluate the antidepressant efficacy in the depressive animal model using MR spectroscopy. Fourteen experimentally naive male Sprague-Dawley rats weighting $160{\sim}180\;g$ were used as subjects. Drug injection group was exposed to the FST except for control group. The drugs were administered subcutaneously (SC) in a volume equivalent to 2ml/kg. And three injections were administered 23, 5, and 1h before beginning the given test. 1H MR spectra were obtained with use of a point resolved spectroscopy (PRESS) localization sequence performed according to the following parameters: repetition time, 2500 ms; echo time, 144 ms; 512 average; 2048 complex data points; voxel dimensions, $1.5{\times}2.5{\times}2.5\;mm^3$ ; acquisition time, 25min. There were no differences in NAA/Cr and Cho/Cr ratio between the right and the left hippocampus both normal control rats and antidepressant-injected rats. Also, no differences were observed in NAA/Cr and Cho/Cr ratio between the normal control rats and the antidepressant-injected rats both the right and the left hippocampus. In this study, we found the recovery of choline signals in the depressive animal model similar to normal control groups as injecting desipramine-HCl which was antidepressant causing anti-immobility effects. Thus, we demonstrated that MR spectroscopy was able to aid in evaluating the antidepressant effect of desipramine-HCl.

  • PDF

The Heterogeneity of Flow Distribution and Partition Coefficient in [15O-H2O] Myocardium Positron Emission Tomography ([15O-H2O] 심근 양전자 단층 촬영에서 혈류 분포의 비균일성과 분배계수)

  • Ahn, Ji Young;Lee, Dong Soo;Kim, Kyung Min;Jeong, Jae Min;Chung, June-Key;Shin, Seung-Ae;Lee, Myung Chul;Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
    • /
    • v.32 no.1
    • /
    • pp.32-49
    • /
    • 1998
  • For estimation of regional myocardial blood flow with O-15 water PET, a few modifications considering partial volume effect based on single compartment model have been proposed. In this study, we attempted to quantify the degree of heterogeneity and to show the effect of tissue flow heterogeneity on partition coefficient(${\lambda}$) and to find the relation between perfusable tissue index(PTI) and ${\lambda}$ by computer simulation using two modified models. We simulated tissue curves for the regions with homogeneous and heterogeneous blood flow over a various flow range(0.2-4.0ml/g/min). Simulated heterogeneous tissue composed of 4 subregions of the same or different size of block which have different homogeneous flow and different degree of slope of distribution of blood flow. We measured the index representing heterogeneity of distribution of blood flow for each heterogeneous tissue by the constitution heterogeneity(CH). For model I, we assumed that tissue recovery coefficient ($F_{MME}$) was the product of partial volume effect($F_{MMF}$) and PTI. Using model I, PTI, flow, and $F_{MM}$ were estimated. For model II, we assumed that partition coefficient was another variable which could represent tissue characteristics of heterogeneity of flow distribution. Using model II, PTI, flow and ${\lambda}$ were estimated. For the simulated tissue with homogeneous flow, both models gave exactly the same estimates, of three parameters. For the simulated tissue with heterogeneous flow distribution, in model I, flow and $F_{MM}$ were correctly estimated as CH was increased moderately. In model II, flow and ${\lambda}$ were decreased curvi-linearly as CH was increased. The degree of underestimation of ${\lambda}$ obtained using model II, was correlated with CH. The degree of underestimation of flow was dependent on the degree of underestimation of ${\lambda}$. PTI was somewhat overestimated and did not change according to CH. We conclude that estimated ${\lambda}$ reflect the degree of tissue heterogeneity of flow distribution. We could use the degree of underestimation of ${\lambda}$ to find the characteristic heterogeneity of tissue flow and use ${\lambda}$ to recover the underestimated flow.

  • PDF