동맥스핀표지 뇌 관류 자기공명영상에서 라벨링 간격 및 지연시간, 표지 두께, 절편 획득 순서의 변화에 따른 관류 신호변화 연구

변재후,박명환,강지연,이진완,이강원,장건호,Byun, Jae-Hoo,Park, Myung-Hwan,Kang, Ji-Yeon,Lee, Jin-Wan,Lee, Kang-Won,Jahng, Geon-Ho 한국의학물리학회 2013 의학물리 Vol.24 No.2

동맥스핀표지(Arterial Spin Labeling: ASL) 뇌 관류 자기공명영상법을 이용한 뇌 관류영상기술이 일반적으로 환자의 질병진단에 일반적으로 사용하기 어려운 이유는 영상을 얻을 때 여러 인자들을 최적화시켜야만 좋은 질의 영상을 얻을 수 있기 때문으로 생각된다. 따라서, 본 논문의 목적은 동맥스핀표지 자기공명영상의 뇌 관류영상을 최적화 하기 위하여 필요한 여러 인자들의 변화에 따른 동맥스핀표지 신호변화를 3.0 테슬라 자기공명영상에서 관찰하는 것이다. 특히, 동맥시 핀표지 자기공명영상 신호 변화가 이들 인자에서 뇌 세포(brain tissues)의 영역에 따라서 어떻게 변화하는가를 평가하였다. 정상 성인 남성 5명을(평균연령 36세; 29세~41세) 대상에서 STAR (Signal Targeting with Alternating Radiofrequency) 동맥스핀표지 방법을 이용하여 3T 자기공명영상에서 영상을 얻었다. 실험은 첫째 영상획득 영역과 라벨링 영역간의 간격 변화에 따른 신호 변화 평가 실험, 둘째 라벨링 후의 시간 변화에 따른 신호 변화 평가 실험, 셋째 라벨링 두께의 변화에 따른 신호 변화 평가 실험, 넷째 슬라이스 획득 순서에 따른 신호 변화 평가실험을 하였다. 획득한 영상의 분석은 회백질과 백질, 전두엽, 측두엽, 후두엽, 두정엽에서의 관류신호변화를 얻어 분석하였다. 본 연구결과는 아래와 같았다: 1) 영상획득 영역과 라벨링 영역간의 간격 변화에 따른 관류 신호 변화 연구결과 전체 절편의 평균 값을 보면 회백질에서 좌측과 우측 모두에서 라벨링 간격이 증가할수록 신호가 낮아지는 경향을 보이고 있다. 라벨링 간격의 변화에 두정엽이 가장 영향을 적게 받고 후두엽이 가장 많은 영향을 받았다. 2) 라벨링 후의 시간 변화에 따른 관류 신호 변화 연구결과 회백질은 라벨링 지연시간 400 ms까지 양쪽 모두 감소하다가 라벨링 지연시간이 1,000 ms까지 증가하였다. 3) 라벨링 두께의 변화에 따른 관류 신호 변화 연구 결과 라벨링 두께가 증가에 따라 회백질과 백질의 신호강도는 점차적으로 증가하다가 120 mm 두께 이후에는 감소하였다. 4) 절편 획득 순서에 따른 관류 신호 변화 연구 결과 절편 획득 순서에 따른 백질과 회백질의 관류신호강도 값은 회백질과 백질 모두 머리의 꼭대기부터 영상을 획득하는 descend에서 신호강도가 높았다. 본 연구에서는 각 실험 조건에 따라서 관류신호 강도가 크게 변화를 하는 것을 보여 주었고, 따라서 실제 환자를 대상으로 관류 영상을 얻고자 할 경우에는 실제 임상 적용 전에 최적화된 프로토콜을 만든 후에 사용을 해야 할 것으로 생각한다. 특히 백질의 뇌 관류영상을 얻는 것은 아직 문제가 있는 것으로 생각이 된다. Currently, an arterial spin labeling (ASL) magnetic resonance imaging (MRI) technique does not routinely used in clinical studies to measure perfusion in brain because optimization of imaging protocol is required to obtain optimal perfusion signals. Therefore, the objective of this study was to investigate changes of perfusion-weighed signal intensities with varying several parameters on a pulsed arterial spin labeling MRI technique obtained from a 3T MRI system. We especially evaluated alternations of ASL-MRI signal intensities on special brain areas, including in brain tissues and lobes. The signal targeting with alternating radiofrequency (STAR) pulsed ASL method was scanned on five normal subjects (mean age: 36 years, range: 29~41 years) on a 3T MRI system. Four parameters were evaluated with varying: 1) the labeling gap, 2) the labeling delay time, 3) the labeling thickness, and 4) the slice scan order. Signal intensities were obtained from the perfusion-weighted imaging on the gray and white matters and brain lobes of the frontal, parietal, temporal, and occipital areas. The results of this study were summarized: 1) Perfusion-weighted signal intensities were decreased with increasing the labeling gap in the bilateral gray matter areas and were least affected on the parietal lobe, but most affected on the occipital lobe. 2) Perfusion-weighted signal intensities were decreased with increasing the labeling delay time until 400 ms, but increased up to 1,000 ms in the bilateral gray matter areas. 3) Perfusion-weighted signal intensities were increased with increasing the labeling thickness until 120 mm in both the gray and white matter. 4) Perfusion-weighted signal intensities were higher descending scans than asending scans in both the gray and white matter. We investigated changes of perfusion-weighted signal intensities with varying several parameters in the STAR ASL method. It should require having protocol optimization processing before applying in patients. It has limitations to apply the ASL method in the white matter on a 3T MRI system.

뇌전이 환자의 조영 증강 후 지연 FLAIR 영상의 유용성

변재후,박명환,이진완,Byun, Jae-Hu,Park, Myung-Hwan,Lee, Jin-Wan 대한디지털의료영상학회 2014 대한디지털의료영상학회논문지 Vol.16 No.1

Purpose: FLAIR image is beneficial for the diagnosis of various bran diseases including ischemic CVS, brain tumors and infections. However the border between the legion of brain metastasis and surrounding edema may not be clear. Therefore, this study aims to investigate the practical benefits of delayed imaging by comparing the image from a patient with brain metastasis before a contrast enhancement and the image 10 minutes after a contrast enhancement. Materials and methods: Of the 92 people who underwent MRI brain metastases in suspected patients 13 people in three patients there is no video to target the 37 people confirmed cases, and motion artifacts brain metastases in our hospital June-December 2013, 18 people measurement position except for the three incorrect patient (male: 11 people, female: 7 people, average age: 60 years) in the target, test equipment, 3.0T MR System (ACHIEVA Release, Philips, I was 8ChannelSENSE Head Coil use Best, and the Netherlands). TR 11000 ms, TE 125 ms, TI2800 ms, Slice Thickness 5 mm, gap 5 mm, is a Slice number 21, the parameters of the 3D FFE, T2 FLAIR variable that was used to test, TR 8.1 ms, TE 3.7 ms, Slice number 240 I set to. The experiment was conducted by acquiring the FLAIR prior to contrast enhancement (heretofore referred to as Pre FLAIR), and acquiring the 3D FFE CE five minutes after the contrast enhancement, and recomposing the images in an axial plane of S/T 3mm, G 0mm (heretofore referred to as MPR TRA CE). Using the FLAIR 10 minutes after the contrast enhancement (heretofore referred to as Post FLAIR) and Pi-View, a retrospective study was conducted. Using MRIcro on the image of a patient confirmed for his diagnosis, the images before and after the contrast media, as well as the CNR and SNR of the MPR TRA CE images of the lesion and the site absent of lesion were compared and analyzed using a one-way analysis of variance. Results: CNR for Pre FLAIR and Post FLAIR were 34.35 and 60.13, respectively, with MPR TRA CE at 23.77 showing no significant difference (p<0.050). Post-experiment analysis shows a difference between Pre FLAIR and Post FLAIR in terms of CNR (p<0.050), but no difference in CNR between Post FLAIR and MPR TRA CE (p>0.050), indicating that the contrast media had an effect only on Pre FLAIR and Post FLAIR. The SNR for the normal site Pre FLAIR was 106.43, and for the lesion site 140.79. Post FLAIR for the normal site was 107.79, and for the lesion site 167.91. MPR TRA CE for the normal site was 140.23 and for the lesion site 183.19, showing significant difference (p<0.050), and post-experiment analysis shows that there was a difference in SNR only on the lesion sites for Pre FLAIR and Post FLAIR (p<0.050). There was no difference in SNR between the normal site and lesion site for Post FLAIR and MPR TRA CE, indicating no effect from the contrast media (p>0.050). Conclusions: This experiment shows that Post FLAIR has a higher contrast than Pre FLAIR, and a higher SNR for lesions, It was not not statistically significant and MPR TRA CE but CNR came out high. Inspection of post-contrast which is used in a high magnetic field is frequently used images of 3D T1 but, since the signal of the contrast medium and the blood flow is included, this method can be diagnostic accuracy is reduced, it is believed that when used in combination with Post FLAIR, and that can provide video information added to the diagnosis of brain metastases.

Liver 확산강조영상 검사 시 조영제 (Primovist) 사용 전 · 후 ADC값 바교: Hepatic metastasis 대상으로

변재후,김영만,이강원 대한자기공명기술학회 2011 대한자기공명기술학회지 Vol.21 No.-

와인색 반영구 문신용 염료가 자기공명영상검사에 미치는 영향 및 발열 감소 방안 연구

박시연,허영철,박영우,강경민,이수빈,변재후 대한자기공명기술학회 2023 대한자기공명기술학회지 Vol.33 No.4

본 연구에서는 자기공명영상 검사 시 와인색 반영구 문신용 염료가 신호 강도에 미치는 영향을 분석하고, 전자파흡수에 의한 발열 감소 방안을 연구하고자 하였다. 한천과 와인색 반영구 문신용 염료를 이용하여 염료가 퍼진 형태의 팬텀(패드형 팬텀)과 한곳에 뭉친 형태의 팬텀(주사형 팬텀)을 제작하였다. 두 팬텀은 전신용 자기공명영상장치에서 고속스핀에코(turbo spin echo, TSE)와 경사에코(gradient echo, GRE) 계열의 펄스열을 이용하여 2D와 3D로 검사하였다. 검사 후 영상 분석은 팬텀의 몸체, 염료, 공기 방울, 배경을 대상으로 총 720회의 신호강도를 측정하였다. 전자파흡수에 의한 발열 감소 방안을 확인하기 위해 삽입형 온도계를 팬텀에 삽입 후 검사 전후 팬텀의 온도 변화를 확인하였다. 이때, 대기 온도의 상승 변화를 고려하기 위해 검사 전 대기 온도를 측정하였고, 발열 감소를 위한 방법으로 장치에 내장된 팬, 젖은 거즈, 얼음을 이용하였다. 신호 강도는 2D 영상보다 3D 영상이 좋았고, TSE 계열이 GRE 계열보다 좋았다. 특히 와인색 반영구 문신용 염료가 있는 부위의 신호강도는 공기 때문에 발생한 자화율 인공물보다 신호강도가 낮게 측정되었다. 온도 측정 검사는 패드형 팬텀과 주사형 팬텀 모두 검사에 의한 온도상승 효과가 있었으며 온도의 저감을 위한 방법으로 얼음 패드, 팬, 젖은 거즈 순서였다. 본 연구를 통해 와인색 반영구 문신용 염료는 자기공명영상 검사에서 영상과 환자의 안전에 문제를 일으킬 수 있음을 확인하였고, 발열 감소 방안으로 얼음 패드가 효과적이었다는 것을 확인할 수 있었다. The purpose of this study was to analyze the effect of a wine-colored semi-permanent tattoo dye on signal intensity during magnetic resonance imaging (MRI) and to determine how to reduce heat generation using electromagnetic wave absorption. Agar and a wine-colored semi-permanent tattoo dye were used to create a phantom with spreading dye (pad phantom) and a phantom with clumped dye (injection phantom). Both phantoms were examined in 2D and 3D using turbo spin echo (TSE) and gradient (GRE) pulse sequences in a whole-body magnetic resonance imaging system. Post-test image analysis measured the signal intensity of the phantom's body, dye, air bubbles, and background a total of 720 times. In order to determine how to reduce heat generation by absorbing electromagnetic waves, an thermometer was inserted into the phantom to check the temperature change before and after the test. In this case, the atmospheric temperature was measured before the test to take into account the change in atmospheric temperature, and a fan built into the device, wet gauze and ice were used to reduce heat generation. The signal strength was greater in 3D images than in 2D images and the TSE series was better than the GRE series. Most notably, the signal strength of the wine-colored semi-permanent tattoo dye was found to be lower than the magnetization-sensitive artifacts caused by air. For the temperature measurement test, both the pad-type phantom and the injection-type phantom increased the temperature during the test, and the methods to reduce the temperature were ice pads, fans, and wet gauze. The results confirm that a wine-colored semi-permanent tattoo dye can cause imaging and patient safety issues in magnetic resonance imaging, and that ice pads are an effective way to reduce fever.

뇌종양 확산강조영상에서 High B-value의 유용성 평가

김진태,변재후,박용성,이래곤,황선광,Kim, Jin-tae,Byun, Jae-Hu,Park, Yong-Seong,Lee, Rae-Gon,Hwang, Seon-Kwang 대한디지털의료영상학회 2015 대한디지털의료영상학회논문지 Vol.17 No.1

This study attempts to examine the clinical usefulness of High b-value DWI (diffusion weighted imaging) for brain tumors with an edema. Subjects were seven patients selected from 65 patients who received an MRI scan for suspected encephalopathy and confirmed diagnosis at our hospital from February to July 2015 (male: 7, average age : 66 years old). As test equipment, 3.0T MR System (ACHIEVA Release, Philips, Best, The Netherlands) and 8Channel SENSE Head Coill were used. DWI checks on the use of the variable TR 5460ms, TE 132ms, Slice Thickness 4mm, gap 1mm, Slice number 29 is, 3D T1WI is TR 8.4ms, TE 3.9ms, matrix size $240{\times}240$, Slice can set 180 piecesIt was. b value of 0, 1,000, 2,000 s/mm2 with DWI acquisition and 3D T1WI enhancement five minutes after the Slice Thickness 3mm, gap 0mm to reconstruct the upper face axis (MPR TRA CE) was. As for the experiment, in b-value 1,000 and 2,000 images, SNR and the lesion at the lesion site and CNR in the normal site opposite to the lesion are measured. WW(window width) and WL(window level) are made equal in MRICro software, and the volume of the lesion is measured from each of b-value and MPR TRA CE image. Using SPSS ver. 1.8.0.0 Mann Whitney-test was analyzed for SNR and CNR, while Kruskal-Wallis test was analyzed for volume.

Knee MR 검사 시 Double Inversion Recovery Sequence의 유용성

이진완,변재후,이강원,장건호 대한자기공명기술학회 2010 대한자기공명기술학회지 Vol.20 No.-

Reference Scan의 NEX 변화가 SNR과 SENSE artifact에 미치는 영향

허영철,이진완,변재후,이강원 대한자기공명기술학회 2010 대한자기공명기술학회지 Vol.20 No.-

확산강조영상에서 척추질환에 따른 현성확산계수 변화에 대한 연구(단순압박골절 vs 전이성 척추암)

이진완,박명환,이강원,변재후,강지연,유영준,원준재 대한자기공명기술학회 2014 대한자기공명기술학회지 Vol.24 No.-

Purpose : Through the DWI, the muscle signal intensity changes at early stage from the injured skeletal muscle could be confirmed, and it is reported as useful for the differentiation diagnosis of the benign and malignant spine compression fracture but there is hardly any study on the apparent diffusion coefficient(ADC) by the disease. So the ADC to quantify the standardized value of each signal intensity and the spread degree of water molecule and the signal to noise(SNR) were compared by using b value 0 400,1400(s/mm²) which are conducted in our hospital in order to comprehend the changes of the simple compression fracture and metastatic spine cancers by b value. Materials and Methods : It was based on total 22 confirmed patients as 11 patients by two diseases on the electronic medical record among the suspected cases of the simple compression fracture and metastatic spine cancers through the MR readings from March 2013 to December 2013, the average age was 71.2, 56.6 by each disease. As the inspection equipment, 1.5 Tesla Achieva MRI system and Syn-Spine Coil were used. For the sequence, as DWI SE-EPI Sagittal(Diffusion Weighted Imaging Spin Echo-Echo Planar Imaging Sagittal) image, the Parameter of TR(ms) 1988, TE(ms) 68, FOV(mm) 300, Mat. 128×128, Thk.(mm) 4, Gap(mm) 0.4, Slice 13, b-factor 0, 400, 1400(s/mm²) was used. About the data analysis, ROI (Region of Interest) of the disease region with high SI(Signal Intensity) in DWI b value 0(s/mm²) image was used, and the normal region was measured from next above the disease region. MRIcro Program was used for calculating each SI with b-value 0, 400, 1400(s/mm²) image, and Metlab Software was used for calculating ADC map with each image of b-value, and MRIcro Program was used for calculating ADC(mm²/s)with this image by applying ROI to same location. For the data analysis, first, 400, 1400(s/mm²) SI was normalize with b value 0 standards by two diseases for the comparative analysis (SI400/SI0, SI400/SI0), second, the ADC and SNR of the normal region and disease region of two diseases were compared for the analysis. For the significance of statistics, T-Test of MS Excel was used. Results : The SI/SI0 normalization value value(SI400/SI0, SI400/SI0) of simple compression fracture was 0.47±0.04, 0.23±0.03, and the standardized value of metastatic spine cancers (SI400/SI0, SI400/SI0) was 0.57±0.07, 0.32±0.08, and the standardized value by two diseases was statistically significant (p<0.05). The b value 400(s/mm²) and 1400(s/mm²)에 대한 ADC(mm²/s) about b value 400 and 1400(s/mm²)of the simple compression fracture disease region was measured as 1.70±0.16, 0.93±0.28, and the metastatic spine cancers was measured as 1.24±0.21, 0.80±0.15. The ADC(mm²/s)about b value 400(s/mm²)in two diseases was statistically significant (p<0.05), but ADC(mm²/s)about b value 1400(s/mm²)was not significant (p>0.05). SNR by the b value (0 /400/1400) of the simple compression fracture and metastatic spine cancers disease region was measured as 65.61±2.61/36.32±2.92/20.22±2.16, 48.40±2.72/39.27±7.51/23.02±6.25. Conclusion : This study was conducted by using b value 0,400,1400(s/mm²)which were tested in our hospital, and there was the measureable difference between the normalization value and the apparent diffusion coefficient of two diseases through b value 400(s/mm²). As a result, if the apparent diffusion coefficient of DWI is applied to the various spinal diseases combining with the general spine MRI, it is judged that will be more help for the correct diagnosis. As the limitations of this study, it could not apply to the various b values, the first outbreak region of disease staging of gender, age and each disease and time, metastatic cancer was not established, and the conclusion of the measure region was obtained by the data of the high signal intensity from simply b value 0(s/mm²) but the image using the contrast media, and it should be supplemented in the future.

와인색 반영구 문신용 염료가 자기공명영상에 미치는 영향 및 발열 감소 방안

박시연,박영우,강경민,이수빈,변재후,허영철 대한자기공명기술학회 2023 대한자기공명기술학회 학술대회 Vol.2023 No.05