• Title, Summary, Keyword: Contrast medium

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Optimization of the Empirical Method to the Enhancement Image of the Four Chambers at the Same Time in the Pediatric Cardiac Computed Tomography (소아 심장 전산화단층촬영 검사에서 4 chamber의 동시 조영증강 영상에 대한 최적화 방안)

  • Park, Chanhyuk;Lee, Jaeseung;Im, Inchul
    • Journal of the Korean Society of Radiology
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    • v.8 no.6
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    • pp.279-285
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    • 2014
  • This study is to have dose reduction and minimization of excessive use of contrast medium in the pediatric cardiac computed tomography and to suggest the optimization plan to acquire the enhancement image of the 4 chambers at the same time by formulating scan delay time in empirical method with considering variables such as contrast medium injection velocity and cardiac approaching time. Quantitative, qualitative and dose assessment were carried out for 30 pediatric patients who had taken the cardiac examination. In conclusion, image enhancement in 4 chambers of the cardiac shows over 300 HU which is proper to pediatric cardiac reading by applying the empirical method with calculating scan delay time according to weight and contrast medium volume and injection velocity. Qualitative image assessments in confidence sharpness and noise have excellence qualitatively. Exposure dose to pediatrics also decreases precisely. Therefore this study is judged to take a important role of making optimization images with advantages of dose reduction and less side effects caused by it's excessive use in clinic.

Usefulness estimating of Time of flight(TOF) during Carotid angio inspection including Aortic arch (Aortic arch를 포함한 Carotid angio 검사 시 Time of flight(TOF)의 유용성 평가)

  • Yoo, Yeong-Jun
    • Korean Journal of Digital Imaging in Medicine
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    • v.15 no.1
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    • pp.1-7
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    • 2013
  • Purpose : The Carotid Angio inspection including Aortic arch applied to wide area is conducted as the Contrast Enhance MR Angiography(CEA) which is using a contrast medium. However it is a burden not only for someone such as infants, pregnant women and patients suffering from kidney failure but continuous use of contrast medium also can be a burden for patients who has been taken follow up inspection since diagnose lesion already. The purpose of this study is to estimate a usefulness of the Time of Flight (TOF) by comparing with CEA. Materials and methods : 10 patients with an average age of 58 (from 45 to 75) who had MRA inspection in our hospital were studied using 3.0 Tesla Aachieva (Philips, Netherland) MRI system and Sense Neuro-Vascular 16 Channels Coil. The same patient was inspected both TOF and CEA simultaneously. The TOF inspection included from Aortic arch to Willis Circle by connecting 3 TOF stacks and so did CEA inspection. The quantitative analysis was conducted through signal to noise ratio(SNR) and contrast to noise ratio(CNR) with soft tissue by setting up an area of interest on CCA bifurcatoin, ICA, ECA, MCA and VA concerning obtained image. In case of qualitative analysis, 3 radiological technologists and 1 radiologist evaluated 4 items (1: Visibility of the blood vessel, 2: Image distortion measure, 3: Overlapping measure with vein, 4: Peripheral blood vessel description measure) into five points scale (1: Very bad, 2: Bad, 3: Normal 4: Good, 5: Very good). Results : Results for the quantitative analysis was obtained by calculating the average of 5 ROIs in case of SNR and CNR separately. Results of SNR, TOF were generally measured higher than CEA (In case of TOF were 166.1, 205.2, 154.39, 172.23, 161.95, and CEA were 92.05, 95.43, 84.76, 73.69, 88.3). But according to the result of CNR, both TOF and CEA were measured similarly as 67.62, 106.71, 55.9, 73.74, 63.46 for TOF and 67.82, 71.19, 60.52, 49.45, 64.07 for CEA. Throughout every results of each ROI, SNR showed statistically meaningful consequence (0.050.05). In case of qualitative analysis the average of each evaluated item was 4.2points and 4.28points in the item1, 2.93points and 4.55points in the item2, 4.6points and 3.13points in the item3, 2.88points and 4.6points in the item4. According to the results TOF was measured higher in the item3 while in the item2 and item4 CEA was higher and in case of the item1, both CEA and TOF were similar. To sum up statistically meaningful results (p<0.05) were shown in the item2, item3 and item4 but not in the item1 (p>0.05). Conclusions : Both TOF and CEA are complementary because each inspection has pros and cons, but when inspect wide area including Aortic arch normally CEA is conducted. But TOF inspection also can be considered as alternative in terms of patients who has difficulty in the contrast medium such as infants, pregnant women and patients suffering from kidney failure and patients during follow up.

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Utilization Model for HCCA EDCA Mixed Mode in IEEE 802.11e

  • Kuan, Cheng;Dimyati, Kaharudin
    • ETRI Journal
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    • v.29 no.6
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    • pp.829-831
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    • 2007
  • This letter proposes an analytical model to characterize medium utilization in IEEE 802.11e operating in HCCA-EDCA mixed mode (HEMM). In contrast to existing works which model the backoff process in individual stations, we consider the channel occupancy pattern. Additionally, our work considers the operation of HEMM, which is not widely documented. We show that the proposed model accurately characterizes medium utilization with no more than 5% error.

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Detection of Extravasated Contrast Media Using an Infrared Ray Based Extravasation Detection Accessory System (적외선 기반의 혈관외유출 검출시스템을 이용한 조영제의 혈관외유출 검출)

  • Kweon, Dae-Cheol;Jang, Keun-Jo
    • Journal of Biomedical Engineering Research
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    • v.30 no.5
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    • pp.412-417
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    • 2009
  • The purpose of this study was to assess the ability of this device during clinically important episodes of extravasation. The extravasation detection accessory (EDA) system was based of infrared ray with detection sensor, an amplifier, alarm device, receiver, cable and a computer based system. This study was a prospective, observational study in which the EDA system was used to monitor the automated mechanical injection of contrast media. Three hundred patients referred for contrast media enhanced body computed tomography studied in a prospective, observation study in which the EDA system was used to identify and interrupt any injection associated with clinically important extravasation. There were 8 true-positive cases, 276 true-negative cases, 15 false-positive cases and 1 false-negative cases. The EDA system had a sensitivity of 88.8% and a specificity of 94.8% for the detection of clinically important extravasation. The EDA system had good sensitivity for the detection of clinically important extravasation and the EDA system has the clinical potential for the early detection of extravasation of the contrast medium that is administered with power injectors.

Physical Parameter Measurement and Theoretical Target Strength Estimation of Juvenile Cod (Gadus macrocephalus)

  • Husni, Iqbal Ali;Hwang, Bo-Kyu;Shin, Hyeon-Ok;Kim, Min-Son
    • Ocean and Polar Research
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    • v.37 no.4
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    • pp.333-340
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    • 2015
  • The contrast (fish body to medium ratio) of density and sound speed were measured to estimate acoustic scattering from small juvenile cod (Gadus macrocephalus) with the Kirchhoff-Ray Mode backscatter model. The density contrast was measured by the density-bottle method and the sound speed contrast was estimated by the time of flight method. The results revealed that the measured density contrasts of juvenile cod varied between 1.003 and 1.029 (mean = 1.014, S.D. = 0.01). On the other hand, sound speed contrasts varied between 1.039 and 1.041 (mean = 1.041, S.D. = 0.001). The relationship between averaged target strength (TS) and total length (TL) established by the model were <$TS_{38kHz}$> = 20log(TL) - 68.8 and <$TS_{38kHz}$> = 20log(TL) - 69.4, respectively.

Congenital Peritoneopericardial Diaphragmatic Hernia in a Dog (개에서의 선천성 복막-심낭 횡경막허니아 1예)

  • Jeong, Seong-Mok
    • Korean Journal of Veterinary Research
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    • v.42 no.3
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    • pp.393-396
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    • 2002
  • A 5 kg, seven-month-old, female Pekingese dog was presented to Seoul National University Veterinary Medical Teaching Hospital with the history of anorexia and exercise intolerance. Muffled cardiac sound and mild abdominal pain were detected in the physical examination. In positive contrast peritoneography, contrast medium was observed in enlarged pericardial sac through the diaphragm. According to the history taking, physical examination and contrast radiographic study, the dog was diagnaosed congenital peritoneopericardial diaphragmatic hernia. Following midline celiotomy, herniated falciform ligament and greater omentum were repositioned to abdrminal cavity. The diaphragmatic defect was closed with absorbable suture. Clinical signs related to peritoneopericardial hernia disappeared immediately after surgical treatment. There had been no evidence of recurrence of the peritoneopericardial hernia for 1 year.

A Study of The Correlation of The Area Dose with Residual CT Contrast Media and MRI Contrast Media during The Use of General Imaging Automatic Exposure Control System (일반촬영 자동노출제어장치 사용 시 잔존 CT 조영제와 MRI 조영제에 따른 면적선량의 상관성 연구)

  • Hong, Chan-Woo;Park, Jin-Hun;Lee, Jung-Min;Seo, Young-Deuk
    • Journal of the Korean Society of Radiology
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    • v.10 no.8
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    • pp.619-627
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    • 2016
  • The purpose of this study is to investigate the effect of CT contrast agent and MRI contrast agent on the area dose in the body when using automatic exposure control system in general radiography. After making rectangular holes in the center of the abdominal thickness paraffin phantom, CT contrast agent and MRI contrast agent were respectively diluted with physiological saline solution for contrast medium dilution ratio of 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, 0:10%. Each experiment was set to 78 kVp, 320 mA, which is the proper condition for KUB photography, and thereafter a total of 30 inspections were made for each dilution ratio using an automatic exposure control device, and the area dose corresponding to the dilution ratio of each contrast agent, Average comparison and correlation analysis were performed on the exposure index. As a result, the CT contrast agent and the MRI contrast agent appeared different in area dose according to the dilution ratio(p<0.05), and as the dilution ratio increased, the area dose increased for CT contrast agent and MRI contrast agent(P<0.05). In each test, the exposure index showed the manufacturer's recommendation of 200-800 EI value, and the exposure index and area dose increased as the area dose increased(p<0.05). In conclusion, CT contrast agent and MRI contrast agent confirmed to increase the area dose by general imaging test using all automatic exposure control device. Therefore, it is considered that it is necessary to perform it after the contrast medium has been excreted sufficiently when using usual imaging test after using the contrast agent in CT and MRI examination.

The Risk Factors for Developing Contrast-induced Nephropathy after the Evaluation of Trauma Patients at a Regional Trauma Center in Korea

  • An, Yoo Mi;Park, Soon Chang;Kim, Hyung Bin;Cho, Young Mo;Lee, Dae Seop;Kim, Yong In;Han, Sang Kyun
    • Journal of Trauma and Injury
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    • v.29 no.4
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    • pp.124-128
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    • 2016
  • Purpose: Computed tomography (CT) with intravenous (IV) contrast is an important step in the evaluation of trauma patients; however, the risk factors for contrast-induced nephropathy (CIN) in these patients remain unclear. This study determined the rate of CIN in trauma patients at a regional trauma center in Korea and identified the risk factors for developing CIN. Methods: We retrospectively reviewed the medical records of 138 patients for the patient demographics, creatinine levels, and vital signs. CIN was defined as an increase in creatinine by 0.5 mg/dL from admission after undergoing CT with IV contrast. Results: Of the patients, 7.2% developed CIN during their admission after receiving IV contrast for CT. In the multivariate analysis, only the creatinine level at presentation (Adjusted odds ratio [aOR], 5.944; 95% confidence interval [CI], 1.486-23.733; p=0.012) and an injury severity score (ISS) greater than 22 (aOR, 1.096; 95% CI, 1.021-1.176; p=0.011) were independently associated with the risk of CIN. Conclusion: CIN is uncommon in trauma patients following CT with IV contrast. The creatinine level at presentation and ISS were independent risk factors for developing CIN in trauma patients.

Syringe Reuse Issues in Automated Contrast Injection System in Dynamic Magnetic Resonance Imaging (조영제 자동주입기를 활용한 자기공명영상 동적검사 시 실린지 재사용의 문제)

  • Son, Soon-Yong
    • The Journal of the Korea Contents Association
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    • v.19 no.11
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    • pp.445-450
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    • 2019
  • This study proves that syringe reuse of automated injection system entails a risk of contrast media reflux and saline solution contamination which are pumped by a piston into the patients' venous cannula in the dynamic MR images, we will be aware of the serious problem. To quantify the contrast media contamination effect on the saline solution, identical volume of the saline solution was collected before and after the contrast injection to the patients' venous cannula following T1 weighted image scanning to verify whether signal intensities differences are observed. The signal intensity of saline solution after the contrast injection was significantly higher than that of saline before injection by 523.43%. This result is due to the backflow that contaminates the saline solution on the opposite side when the contrast agent is injected. In conclusion, the syringe used to inject contrast medium. causes cross-contamination due to contrast reflux. Therefore, even if the same patient's examination is used for quantitative analysis, the error should be avoided by changing the acquisition sequence or replacing the syringe.