Delayed Lesions on Diffusion-Weighted Imaging in Initially Lesion-Negative Stroke Patients

김기태,Beom Joon Kim,Jaewon Huh,Seong Kyu Yang,Mi Hwa Yang,Moon-Ku Han,Cheolkyu Jung,Byung Se Choi,Jae Hyoung Kim,Hee-Joon Bae 대한뇌졸중학회 2021 Journal of stroke Vol.23 No.1

Background and Purpose: Lesions on diffusion-weighted imaging (DWI) occasionally appear on follow- up magnetic resonance imaging (MRI) among initially DWI-negative but clinically suspicious stroke patients. We established the prevalence of positive conversion in DWI-negative stroke and determined the clinical factors associated with it. Methods: This retrospective, observational, single-center study included 5,271 patients hospitalized due to stroke/transient ischemic attack (TIA) in a single university hospital during 2010 to 2017. Patients without initial DWI lesions underwent follow-up DWI imaging as a routine practice. Adjusted hazard ratios (aHRs) for recurrent stroke risk according to positive conversion were determined using Cox proportional hazard regression. Adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for positive conversion among initially DWI-negative patients were estimated. Results: In total, 694 (13.2%) patients (mean±standard deviation age, 62.9±13.7 years; male, 404 [58.2%]) were initially DWI-negative. Among them, 22.5% had positive-conversion on follow-up DWI. Positive conversion was associated with a higher risk of recurrent stroke (aHR, 3.12; 95% CI, 1.56 to 6.26). Early neurologic deterioration (aOR, 15.1; 95% CI, 5.71 to 47.66), atrial fibrillation (aOR, 6.17; 95% CI, 3.23 to 12.01), smoking (aOR, 3.76; 95% CI, 2.19 to 6.63), pre-stroke dependency (aOR, 1.62; 95% CI, 1.15 to 2.27), objective hemiparesis (aOR, 4.39; 95% CI, 1.90 to 10.32), longer symptom duration (aOR, 2.17; 95% CI, 1.57 to 3.08), high cholesterol (aOR, 4.70; 95% CI, 1.78 to 12.77), National Institutes of Health Stroke Scale score (aOR, 1.44; 95% CI, 1.08 to 1.91), and high systolic blood pressure (aOR, 1.01; 95% CI, 1.00 to 1.02) were associated with a higher incidence of lesions with delayed appearance. Regarding the location of lesions on follow-up DWI, 34.6% and 21.2% were in the cortex and brainstem, respectively. Conclusions: In DWI-negative stroke/TIA, positive conversion is associated with a higher risk of recurrent stroke. DWI-negative stroke with factors related to positive conversion may require followup MRI for a definitive diagnosis.

광고의 음주운전 억제심리 유발효과에 관한 연구

정철우 이실학회(구 한국경찰이론과실무학회) 2012 경찰연구논집 Vol.9 No.-

본 연구의 목적은 음주운전 억제를 위한 광고의 효과를 측정하는 것이다. 본 연구에 이용된 자료는 도로교통공단 경기도지부에서 교습생들 466명을 대상으로 설문조사한 것이다. 세 가지 종류의 광고안-①음주운전을 할 경우 운전자가 불구가 된다는 안, ②음주운전자는 다른 운전자나 보행자를 해칠 수 있다는 안, ③ 음주운전자의 가족이 슬퍼한다는 안-을 제시하여, 음주광고가 얼마나 음주운전 억제심리를 유발시키는 지를 효과척도로 하여 분석하였다. 연구결과는 다음과 같다. 첫째, 광고안 간에는 유의한 차이가 있었으며 가족의 슬픔이 담긴 내용의 안이 가장 효과적이었고, 회귀분석결과 광고효과에도 가장 큰 영향력을 미치는 것으로 나타났다. 그리고 이러한 광고안을 술집지역에서 홍보한다면 음주운전 억제심리가 클 것으로 예상되었다. 향후, 음주운전자에 대한 보다 많은 변수를 고려하여 광고의 효과를 연구하여야 할것이다. The purpose of this study is to measure of Effectiveness of Public Advertisement for DWI(Driving While Intoxicated) deterrence. The data used in this study are drawn from a self-reported survey -based learners-(seven scores Likert scales were used: 1 is the lowest, and 7 is the highest in DWI deterrence effectiveness ) conducted in Road Traffic Authority Gyeongi Do branch, and the sample cases were 466. Three types of Advertisement alternatives-1) one who offended DWI was supposed to be crippled, 2) one who offend DWI could do harm to other drivers or pedestrian, 3) if one offend DWI whoes family might felt sadness-were suggested. MOE(Measurement Of Effectiveness) was that how much the advertisements aroused their deterrence psychology effectiveness not to offend DWI. The results of this study are as follows. First, there is a significant difference(sig. .000) in arousing their deterrence psychology effectiveness between three advertisement alternatives, and the third advertisement alternative which shows DWI offender`s family might felt the sadness it the highest in the MOE. Second, multiple regression model was established to measure the impacts of each advertisement alternatives, the result shows that the regression model is significant and the impact of the third alternative to MOE is the highest and the nexts are the second, the first ones. Consequently, when the third advertisement alternative is displayed at the pub, the deterrence psychology effectiveness not to offend DWI is the highest. Future study should consider more variables, for example driver`s education, income, drunk driving records etc and other types of advertisement alternatives.

형벌의 음주운전 억제효과에 관한 실증적 연구

정철우 ( Cheol Woo Jeong ),정진성 ( Jin Sung Jeong ) 한국경찰법학회 2012 경찰법연구 Vol.10 No.2

The purpose of this study is to provide basic materials for establishing DWI deterrence policy by analysing the effectiveness of punishment. Data of 640 drivers` written opinion of investigation from Gumjung police station in 2006. This study analysed the effectiveness of fine with abidance duration and compared effectiveness of fine and imprisonment. For these analysis, multiple regression model and Analysis of Covariance(ANCOVA) method were conducted. The results of these analysis were as follows. First, multiple regression model showed that fine to the DWI offenders didn`t have a deterrence effectiveness. And the more fine was sentenced, the shorter was abidance duration. Second, the result of ANCOVA showed that imprisonment was more effective than fine in DWI deterrence. The abidance duration of imprisonment was longer by two times than that of fine. These study results suggested a policy implications. A renewed regulation must be passed to make possible a short-term imprisonment(e.g., 2-3 days on weekend) for DWI, especially for chronic DWI offenders, which will be able to reduce recidivism rates of DWI. This study had two major limitations. First, socioeconomic variables such as education level, marriage status, and economic condition were not controlled. Second, the study area was constrained to only one city, which put restraint on generalization of the study results. Nevertheless, this study made valuable contributions in that analysing the deterrence effectiveness of fine and imprisonment.

팬텀과 파이썬 OpenCV를 이용한 Simultaneous Multi-Slice RESOLVE DWI의 공기 자화율에 의한 기하학적 왜곡 변화 정량화 연구

김택수,김도연,강성진,김나영 대한자기공명기술학회 2023 대한자기공명기술학회지 Vol.33 No.3

Free air near human tissues and lesions can cause image distortion during DWI tests, making lesion differentiation difficult. This study used a phantom to quantify distortion changes caused by air susceptibility in SMS-RESOLVE DWI, which reduces geometric distortions. The phantom was designed as a cylinder with internal air space, distilled water, gelatin, and a mixture of materials were placed inside the phantom to create various magnetic susceptibility distortions in a controlled environment. After conducting the experiment with air by changing the alignment of the phantom, the experiment was conducted in the same way with the mixture, and then with distilled water. Images were captured with a 3T MRI device using T2WI, C DWI, and SMS-RESOLVE DWI, and similarity measurements were conducted using Python OpenCV. The results revealed that the air-filled state in SMS-RESOLVE DWI b0 exhibited the lowest image distortion, with an average SSIM of 0.898 and an average MSE of 0.068. The distortion change due to air susceptibility in SMS-RESOLVE DWI generated an image similarity difference of -0.033 to 0.003 for both SSIM and MSE based on the b0 reference image. Although SMS-RESOLVE DWIb1000 had minimal or attenuated image similarity differences, focusing on improving SNR could provide enhanced diagnostic performance. The use of open-source libraries to minimize errors in image processing and analyze similarity offers new models for future research projects.

A Comparative Quantitative Analysis of Magnetic Susceptibility Artifacts in Echo Planar and PROPELLER Diffusion-weighted Images

조재환,이해각,양한준,이귀원,박용순,정운관 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.2

In this study, the authors investigated whether periodically-rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) diffusion-weighted imaging (DWI) can remove magnetic susceptibility artifacts and compared apparent diffusion coefficient (ADC) values for PROPELLER DWI and the common echo planar (EP) DWI. Twenty patients that underwent brain MRI with a metal dental implant were selected. A 3.0T MR scanner was then used to obtain EP DWI, PROPELLER DWI, and corresponding apparent diffusion coefficient (ADC) maps for a b-value of 0 and 1,000 s/mm². The frequencies of magnetic susceptibility artifacts in four parts of the brain (bilateral temporal lobes, pons, and orbit) were selected. In the ADC maps, we measured the ADC values of both sides of the temporal lobe and the pons. According to the study results, the frequency of magnetic susceptibility artifacts in PROPELLER DW images was lower than it was in EP DW images. In ADC maps, the ADC values of the bilateral temporal lobes and the pons were all higher in PROPELLER ADC maps than in EP ADC maps. Our findings show that when a highfield MRI machine is used, magnetic susceptibility artifacts can distort anatomical structures and produce high-intensity signals. Furthermore, our findings suggest that in many cases, PROPELLER DWI would be helpful in terms of achieving a correct diagnosis.

앞 뒤와 "위 아래"의 비교 연구

손평효 ( Pyeong Hyo Son ) 경남대학교 인문과학연구소 2013 人文論叢 Vol.31 No.-

이 글은 공간말 ‘앞, 뒤’와 ‘위, 아래’의 형태와 의미, 복합어 형성 등을 비교하기 위한 목적으로 작성되었다. 역사적으로 이들은 형태 면에서 혼란된 모습을 보였는데, 주로 통합되는 음운 환경과 연관성이 있었다. 합성어 형성에서는 ‘앞, 뒤’가 ‘위, 아래’보다 훨씬 생산적인 양상을 보였다. 품사로 보면 합성명사가 압도적으로 많았다. 합성동사는 앞/뒤-합성어의 경우 적지 않은 예를 보였지만 위/아래-합성어의 경우 찾아보기가 어려웠다. 이들 합성어들은 모두 통사적 합성어로서의 짜임새를 보였다. 그 까닭은 선행어에 ‘앞, 뒤’와 ‘위, 아래’가 위치한 것이 근본적인 원인이었다. 합성어 형성에서 ‘앞, 뒤’와 ‘위, 아래’는 공간 의미뿐만 아니라 시간, 추상 의미 등 다양한 의미 양상을 보였다. 아울러 파생어 형성에서는 ‘뒤’와 ‘웃’을 중심으로 그 의미와 쓰임에 대해 살펴보았다. This paper has the purpose of the ‘ap, dwi’ and ‘wi, arae’ the form and meaning, complex-word formation, and to compare. To show they are confused in form historically, mainly phonological environment that integrates relevant. Compound formation, ‘ap, dwi’ is ‘wi, arae’ than production aspects. Compound nouns in speech is overwhelming. Ap/dwi-compound certain number of the compound-verb, but wi/ arae-compound may find it harder to see. And they all have syntacticcompound, because ‘ap, dwi’ and ‘wi, arae’ in the antecedent position. In the formation of compound words, ‘ap, dwi’ and ‘wi, arae’ show various aspects such as space, means and time, the abstract meaning.

전이성 척추암 환자의 확산강조영상 검사 시 조영제 주입 전·후 ADC값의 변화에 대한 고찰

김응찬(Engchan Kim),김기홍(Kihong Kim),박철수(Cheolsoo Park),이선엽(Sunyeob Lee),유흥준(Heungjoon Yoo),조재환(Jaehwan Cho),장현철(Hyuncheol Jang),김보희(Bohui Kim),한만석(Manseok Han) 한국방사선학회 2011 한국방사선학회 논문지 Vol.5 No.1

전이성 척추암 환자를 대상으로 1.5 T MR 기기에서 조영제 주입 전·후 확산강조영상에서 전이가 된 요추의 신호대 잡음비, 대조도대 잡음비, 현성 확산 계수가 어떤 변화를 나타내는지 알아보고자 하였다. 영상의 정량적 분석에서는 전이성 척추암 그룹의 경우 조영제 주입 전 확산강조영상에서 전이성 척추암이 있는 부위와 척추암이 있는 부위의 위, 아래 척추등 세 부위의 신호대 잡음비는 척추암이 있는 부위에서 낮게 나타났으며 조영제 주입 후 확산강조영상에서는 조영제 주입 전보다 세 부위 모두 신호대 잡음비가 상대적으로 증가하였으며 척추암이 있는 부위의 위, 아래 척추등 두 부위 에서는 대조도대 잡음비가 상대적으로 증가했다. ADC map영상에서는 조영제주입 전에서 신호대 잡음비는 척추암이 있는 부위에서 높게 나타났으며 조영제 주입 후에서는 조영제 주입 전보다 전이성 척추암이 있는 부위와 척추암이 있는 부위의 위, 아래 척추등 세 부위 모두 신호대 잡음비가 상대적으로 감소했다. ADC map영상에서의 현성 확산 계수는 조영제 주입 전에서 현성 확산 계수는 척추암이 있는 부위에서 낮게 나타났으며 조영제 주입 후에서는 주입 전보다 세 부위 모두 현성 확산 계수가 상대적으로 감소했다. 정상 그룹의 경우 확산강조영상에서 요추체 3, 4, 5번 세 부위 모두 신호대 잡음비가 상대적으로 증가했고 ADC map영상에서는 조영제주입 후 확산강조영상에서 세 부위 모두 신호대 잡음비가 상대적으로 감소했다. ADC map영상에서의 현성 확산 계수는 세 부위 모두 현성 확산 계수가 상대적으로 감소했다. 영상의 정성적 분석에서 조영제 주입 후 확산강조영상에서 전이성 척추암이 있는 부위의 신호강도가 증가하였고 ADC map영상에서는 신호강도가 감소하였다. 조영제 주입 후 확산강조영상에서 전이성 척추암이 있는 부위와 척추암이 있는 부위의 위, 아래 척추 등 세 부위 모두 신호대 잡음비와 대조도대 잡음비가 증가하고 현성확산계수가 감소하는 결과를 얻었고 조영제 주입 후 확산강조영상이 여러 가지 척추질환으로의 적용에 도움을 줄 것이라 사료된다. To examine the possible changes in the SNRs, CNRs, and ADC values for lumbar spines with metastasis based on the DW images before and after contrast agent injection taken from metastatic spinal cancer patients using a 1.5 T MR machine. The quantitative analysis revealed that in case of spinal cancer subjects, both SNRs and CNRs at all of those assessed locations significantly increased on the DWI after contrast agent injection compared to before, while on the ADC map images, SNRs significantly decreased. On the other hand, significantly decreased ADC values at all the assessed locations were found on the ADC map images. With reference to the normal group, significantly increased SNRs were found at all of the assessed locations on the DWI image after injection compared to before, while significantly decreased SNRs were found on the ADC map images. Also, significantly decreased ADC values at all the assessed locations were found on the ADC map images. For the qualitative analysis, after contrast agent injection, significantly increased signal intensities were found at the locations with spinal cancer on the DWI. In contrast, significantly decreased signal intensities were found on the ADC map images. The implication from the results showing that SNR and CNR significantly increased while ADC value significantly decreased at, above, and below the location of metastatic spinal cancer on DWI after contrast agent injection is that DWI obtained after contrast agent injection can be made available for wider application to vertebral disorders.

Development and Application of a Deep Convolutional Neural Network Noise Reduction Algorithm for Diffusion-weighted Magnetic Resonance Imaging

Dong-Kyoon Han,Kyuseok Kim,Youngjin Lee 한국자기학회 2019 Journal of Magnetics Vol.24 No.2

Diffusion-weighted imaging (DWI) is frequently used in the field of diagnostic medicine to detect various human diseases. In DWI, noise suppression is very important for achieving high detection accuracy of diseases. In this study, we develop a deep convolutional neural network (Deep-CNN) noise reduction algorithm and evaluate its effectiveness in DWI by performing both simulations and real experiments with a 1.5- and a 3.0-T MRI system. The results validate the proposed Deep-CNN algorithm for DWI. Compared with previously developed non-local means (NLM) algorithms, the proposed Deep-CNN algorithm achieves superior quantitative results. In conclusion, the quantitative results verify that the proposed Deep-CNN algorithm has higher noise reduction efficiency and image visibility than previously developed algorithms for DWI.

Diffusion-Weighted MR Imaging of Unicystic Odontogenic Tumors for Differentiation of Unicystic Ameloblastomas from Keratocystic Odontogenic Tumors

Yifeng Han,Xindong Fan,Lixin Su,Zhenfeng Wang 대한영상의학회 2018 Korean Journal of Radiology Vol.19 No.1

Objective: Differentiating unicystic ameloblastomas from keratocystic odontogenic tumors (KCOT) is necessary for the planning of different treatment strategies; however, it is difficult based on conventional CT and MR sequences alone. The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and apparent diffusion coefficients (ADCs) in the differentiation of the two tumors. Materials and Methods: We prospectively studied 40 patients with odontogenic cysts and tumors of the maxillomandibular region using conventional MR imaging and DWI. ADCs were measured using 2 b factors (500 and 1000). Results: Unicystic ameloblastomas (n = 11) showed free diffusion on DWI and a mean ADC value of 2.309 ± 0.17 x 10-3 mm2/s. KCOT (n = 15) showed restricted diffusion on DWI with a mean ADC value of 0.923 ± 0.20 x 10-3 mm2/s. The ADC values of unicystic ameloblastomas were significantly higher than those of KCOT (p < 0.001, Mann-Whitney U-test). An ADC cut-off value of 2.0 x 10-3 mm2/s to differentiate KCOT and unicystic ameloblastomas resulted in a 100% sensitivity and 100% specificity. Dentigerous cysts (n = 3) showed restricted diffusion on DWI and similar ADC values (1.257 ± 0.05 x 10-3 mm2/s) to those of KCOT. Conclusion: Diffusion-weighted imaging and ADC determination can be used as an adjuvant tool to differentiate between unicystic ameloblastomas and KCOT, although the ADC values of dentigerous cysts overlap with those of KCOT.

상지 움직임이 태권도 발차기 총 수행시간에 미치는 영향

권태원(Kwon, Tae-Won),박현수(Park, Hyeon-Su) 한국체육과학회 2021 한국체육과학회지 Vol.30 No.2

In this study, 18 Taekwondo players are required to perform kicks such as Dollyeo-chagi, Balbutyeo-chagi, Dwi-chagi, Dwi Huryeo-chagi, Dolgae-chagi in the upper limb fixed state and the upper limb free state. To determine how the mean difference of total performance time of kicking is different, independent t verification was conducted and analyzed. As a result, the following conclusions were drawn. First, the upper limbs fixation was shown to increase the speed of kicking by limiting the movement of the shoulder joint and flexion of the elbow joint, thereby increasing the total performance time of kicking. Second, Dollyeo-chagi, Balbutyeo-chagi, Dwi-chagi and Dwi Huryeo-chagi had all statistically significant differences. However, in this study, the characteristic kick was Dolgae-chagi, which showed that the upper limb movement had a significant impact on the total performance time compared to other kicks. To sum up these conclusions, according to the upper limb movement, the mean difference in the total performance time of Taekwondo kicks is shown, which is consistent with prior research in other sports. Besides, the characteristic of kicking in the upper limb free state contributed to the flexion of the hip joint can be wider, and the kick of the straight line movement was carried out quickly, it is believed that the sequence of muscles required for kicking can be activated sequentially. Therefore, in Taekwondo training, which is a high proportion of lower limbs training, if we conduct both the upper and lower limbs training to increase coordination, it is judged that the total performance time of kicks will be reduced, and it will contribute to the improvement of the competition skill.