• Title/Summary/Keyword: Diffusion weighted image(DWI)

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A Study on Usefulness of Diffusion Tensor Imaging (DTI6D) in Brain Ischemic Disease (뇌 허혈성 질환 확산텐서영상(DTI6D)의 임상적 유용성에 관한 연구)

  • Goo, Eunhoe
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.1
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    • pp.223-228
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    • 2013
  • We evaluated the usefulness of $DTI_{6D}$ which was acquiring six direction diffusion data through compared to $DWI_{3D}$. Mean SNR and CNR were on $DWI_{3D}$ and $DTI_{6D}$ $44.01{\pm}13.36$, $37.15{\pm}11.44$ (p=0.029) and $18.47{\pm}9.66$, $19.88{\pm}9.20$(p=0.017). The number of lesions were $311{\pm}26.87$, $224.5{\pm}26.16$(p=0.041) on $DTI_{6D}$ and $DWI_{3D}$. Twenty patients were the more detected brain infarction lesion on $DTI_{6D}$. But there is no one the more detected on $DWI_{3D}$. And the more three direction diffusion data could get more information. However, we need to consider about the time consumption compared to DWI.

The Study on Reduction of Image Distortion by using Single-Shot Turbo Spin Echo in Brain Stem Diffusion MRI (자기공명 확산강조영상검사 시 영상왜곡 감소에 관한 연구)

  • Choi, Kwan-Woo;Lee, Ho-Beom;Na, Sa-Ra;Yoo, Beong-Gyu;Son, Soon-Yong
    • Journal of the Korean Society of Radiology
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    • v.10 no.4
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    • pp.279-284
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    • 2016
  • Single-shot echo planar imaging(SS-EPI) is well established as high sensitivity for ischemic stroke. However, it is prone to susceptibility artifact in brain stem that diminish the image quality. single-shot turbo spin echo(SS-TSE) is a new DWI technique that can reduce susceptibility artifact. Thus, this research was conducted so as to reduce geometric distortion in brain stem by using single-shot turbo spin echo technique. Thirty patients without brain disease underwent diffusion MR on a 3T scanner with SS-EPI and SS-TSE. Obtained images with both sequences were analyzed for geometric distortion and error percentage as well. Image quality in terms of geometric distortion of SS-TSE were found to be significantly better than those for SS-EPI. And error percentage was considerably reduced for 2.4% of b0 image(from 11.1% to 8.7%), 1.2% of b1000 image(from 11.4% to 10.1%), respectively. In summary, diffusion MR using SS-TSE significantly reduce geometric distortion compared to SS-EPI in brain stem and may provide improved diagnostic performance.

Diffusion-Weighted MR Imaging of the Brain Tumors: The Clinical Usefulness (두개강내 종양의 확산강조자기공명영상: 임상적 유용성)

  • 이영철;서정진;정광우;강형근;김윤현
    • Investigative Magnetic Resonance Imaging
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    • v.4 no.1
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    • pp.34-41
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    • 2000
  • Purpose: To evaluate the clinical usefulness of diffusion weighted MR imaging(DWI) in the differential diagnosis of brain tumors. Materials and methods: DWI and conventional MR images of nineteen patients with brain tumors(10 metastatic tumors, 4 high grade gliomas, 4 low grade astrocytomas, one oligodendroglioma)were obtained on 1.5T unit. DWI was obtained using single shot spin echo planar imaging with b-value near 1000. We analyzed the signal intensities of lesions including solid portion, necrotic or cystic portion and peritumoral edema of brain tumors (classified five grades comparison with the signal intensities of brain parenchyma and CSF)and calculate the SIR(signal intensity ratio)of lesions to the contralateral normal brain parenchyma. We analyzed statistically the signal intensities and SIR of tumors using independence T test. Results: In solid portions of tumors, all the metastatic tumors and high grade gliomas showed high signal intensities, but low grade astrocytomas and oligodendroglioma showed iso or slight high signal intensities to the normal brain parenchyma. The SIR of solid portion has positive correlation with malignant pot ential(metastatic tumors 1.52, high grade gliomas 1.38, low grade astrocytomas 1.16, oligodendroglioma 1.31)(p < 0.05). In peritumoral edema where seen in 14 tumors, seven of 10 metastatic tumors and two of 4 high grade gliomas showed iso signal intensities, whereas edemas in other 5 brain tumors showed hyperintense to the normal brain parenchyma. The SIRs of peritumoral edemas in metastatic tumors (1.14) was lower than high grade gliomas(1.31),but statistically insignificant. The SIR of cystic or necrotic portion of brain tumors was 0.63. In non enhancing solid portions, three of six cases showed hyperintense to the adjacent peritumoral edema. Conclusion: On DWI, the signal intensities of solid portion has positive correlation with malignant potential, and perilesional edema of brain tumors appear various signal intensities owing to "T2 shine through effect" and the extensiveness of vasogenic edema. Another merit using DWI on the evaluation of brain tumors is to improved better delineation of tumor margins from the adjacent edemas, especially at the non enhancing solid portion of the tumors.

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Diffusion-weighted MR Imaging of Hypoxic-Ischemic Encephalopathy (저산소성-허혈성 뇌증의 확산강조영상 소견)

  • Choi, Hye-Young;Choi, Dae-Seob;Ryoo, Jae-Wook;Cho, Jae-Min;Ko, Eun-Sook;Shin, Tae-Beom;Na, Jae-Beom;Choi, Nak-Cheon
    • Investigative Magnetic Resonance Imaging
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    • v.12 no.1
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    • pp.49-54
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    • 2008
  • Purpose : The purpose of this study was to determine the characteristics of hypoxic-ischemic encephalopathy (HIE) on diffusion-weighted imaging (DWI) and the role of DWI for the diagnosis of HIE. Materials and Methods : Six patients with HIE underwent MRI including DWI. MR examinations were performed within 4 - 32 days (mean, 11.8 days) after hypoxic brain insult. We assessed the distribution of the lesions and compared the DWI and T2, FLAIR images for the subjective conspicuity of the lesions. Results : In all patients, symmetrical hyperintense lesions were demonstrated in the bilateral basal ganglia on T2, FLAIR, and DWI. On ADC map image, the lesions were hypointense in four of six patients and isointense in other two patients. Lesion conspicuity on DWI was higher than on T2 and FLAIR images in four of six patients and similar in other two patients. For the involvement of the cortex and subcortical white matter, in five of six patients, bilateral symmetric hyperintense lesions were seen on T2, FLAIR, and DWI. Lesion conspicuity on DWI was higher than on T2 and FLAIR images in three of them and similar in other two patients. On ADC map image, the lesions showed hypointensity in three of five patients and isointensity in other two patients. For the involvement of the deep cerebral white matter, T2, FLAIR, and DWI showed bilateral symmetric hyperintense lesions in four of six patients. Among them, Lesion conspicuity on DWI was higher than on T2 and FLAIR images in only one patient. Conclusion : HIE is characterized by symmetrical hyperintense lesions in the bilateral basal ganglia, cerebral cortex, and white matter on DWI and the lesions are more conspicuously demonstrated on DWI than on T2 and FLAIR images.

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Rapid Regression of White Matter Changes in Hypoglycemic Encephalopathy (저혈당성 뇌병증에서 뇌백질 변화의 빠른 퇴행)

  • Son, Sang-Wook;Lee, Kye-Ho;Yoo, Dong-Soo
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.4
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    • pp.357-361
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    • 2014
  • Purpose : In a previous report, it took several days for white matter lesions to regress in hypoglycemic encephalopathy. We present a case of rapid diffusion-weighted image (DWI) changes in hypoglycemic encephalopathy. Case Report: A 58-year-old male patient was found semi-comatous with the only abnormality in his laboratory tests showing hypoglycemia (44 mg/dL). After rapid correction of glucose level, immediate brain DWI showed bilateral subcortical white matter lesions. After about 5 hours, follow-up DWI showed resolved subcortical white matter lesions, with newly-appeared bilateral fronto-temporo-parietal cortical lesions. Conclusion: Both white matter and cortex involvement in hypoglycemic encephalopathy has been shown in several reports, but rapid regression of white matter changes in hypoglycemic encephalopathy has been rarely reported. It is important to know that MR imaging changes in hypoglycemic encephalopathy can be made as quick as just a few-hour-long.

Usefulness of the High B-value DWI in Brain Tumors (뇌종양 확산강조영상에서 High B-value의 유용성 평가)

  • Kim, Jin-tae;Byun, Jae-Hu;Park, Yong-Seong;Lee, Rae-Gon;Hwang, Seon-Kwang
    • Korean Journal of Digital Imaging in Medicine
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    • v.17 no.1
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    • pp.33-41
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    • 2015
  • 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.

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Comparative Analysis of Signal Intensity and Apparent Diffusion Coefficient at Varying b-values in the Brain : Diffusion Weighted-Echo Planar Image ($T_2^*$ and FLAIR) Sequence (뇌의 확산강조 영상에서 b-value의 변화에 따른 신호강도, 현성확산계수에 관한 비교 분석 : 확산강조 에코평면영상($T_2^*$ 및 FLAIR)기법 중심으로)

  • Oh, Jong-Kap;Im, Jung-Yeol
    • Journal of radiological science and technology
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    • v.32 no.3
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    • pp.313-323
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    • 2009
  • Diffusion-weighted imaging (DWI) has been demonstrated to be a practical method for the diagnosis of various brain diseases such as acute infarction, brain tumor, and white matter disease. In this study, we used two techniques to examine the average signal intensity (SI) and apparent diffusion coefficient (ADC) of the brains of patients who ranged in age from 10 to 60 years. Our results indicated that the average SI was the highest in amygdala (as derived from DWI), whereas that in the cerebrospinal fluid was the lowest. The average ADC was the highest in the cerebrospinal fluid, whereas the lowest measurement was derived from the pons. The average SI and ADC were higher in $T_2^*$-DW-EPI than in FLAIR-DW-EPI. The higher the b-value, the smaller the average difference in both imaging techniques; the lower the b-value, the greater the average difference. Also, comparative analysis of the brains of patients who had experienced cerebral infarction showed no distinct lesion in the general MR image over time. However, there was a high SI in apparent weighted images. Analysis of other brain diseases (e.g., bleeding, acute, subacute, chronic infarction) indicated SI variance in accordance with characteristics of the two techniques. The higher the SI, the lower the ADC. Taken together, the value of SI and ADC in accordance with frequently occurring areas and various brain disease varies based on the b-value and imaging technique. Because they provide additional useful information in the diagnosis and treatment of patients with various brain diseases through signal recognition, the proper imaging technique and b-value are important for the detection and interpretation of subacute stroke and other brain diseases.

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Usefulness of High-B-value Diffusion - Weighted MR Imaging for the Pre-operative Detection of Rectal Cancers (B-values 변환 자기공명영상: 국소 직장암 수술 전 검출을 위한 적합한 b-value 유용성)

  • Lee, Jae-Seung;Goo, Eun-Hoe;Lee, Sun-Yeob;Park, Cheol-Soo;Choi, Ji-Won
    • The Journal of the Korea Contents Association
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    • v.9 no.12
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    • pp.683-690
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    • 2009
  • The purpose of this study is to evaluate the usefulness of high-b-values diffusion weighted magnetic resonance imaging for the preoperative detection of focal rectum cancers. 60patients with diffusion weighted imaging were evaluated for the presence of rectal cancers. Forty were male and twenty were female, and their ages ranged from 38 to 71 (mean, 56) years. Used equipment was 1.5Tesla MRI((GE, General Electric Medical System, Excite HD). Examination protocols were used the fast spin echo T2, T1 weighted imaging. All examination protocols were performed by the same location with diffusion weighted imaging for accuracy detection. The b-values used in DWI were 250, 500, 750, 1000. 1500, 2000$(s/mm^2)$. The rectum, bladder to tumor contrast-to-noise ratio (CNR) of MR images were quantitativlely analyzed using GE software Functool tool, four experienced radiologists and three radiotechnologists qualitatively evaluated image quality in terms of image artifacts, lesion conspicuity and rectal wall. These data were analysed by using ANOVA and Freedman test with each b-value(p<0.05). Contrast to noise ratio of rectum, bladder and tumor in b-value 1000 were 27.21, 24.44, respectively(p<0.05) and aADC value was $0.73\times10^{-3}$. As a qualitative analysis, the conspicuity and discrimination from the rectal wall of lesions were high results as $4.0\pm0.14$, $4.4\pm0.16$ on b-value 1000(p<0.05), image artifacts were high results as $4.8\pm0.25$ on b-value 2000(p<0.05). In conclusion, DWI was provided useful information with depicting the pre-operative detection of rectal cancers, High-b-value 1000 image was the most excellent DWI value.

A Change of Apparent Diffusion Coefficient in Diffusion Weighted Imaging Applied with Rectangular FOV Technique (확산강조영상 검사 시 rectangular FOV 적용에 따른 ADC 값의 변화)

  • Na, Sa-Ra;Choi, Kwan-Woo;Koo, No-Hyun;Yoo, Beong-Gyu;Son, Soon-Yong
    • Journal of the Korean Society of Radiology
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    • v.10 no.7
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    • pp.545-550
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    • 2016
  • The purpose of this study is to improve the mapping between functional image and conventional image by using rectangular FOV technique. Diffusion weighted imaging which is widely used for stroke was acquired by reducing the FOV and compared each Apparent Diffusion Coefficient(ADC). As a result, there is no significant difference of each ADC value in one-way-anova analysis and post-hoc analysis. Thus, Mismatching problem may be improved by matching the FOV with rectangular FOV technique because there is no difference in ADC values.

Analysis of Image Distortion on Magnetic Resonance Diffusion Weighted Imaging

  • Cho, Ah Rang;Lee, Hae Kag;Yoo, Heung Joon;Park, Cheol-Soo
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.381-386
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    • 2015
  • The purpose of this study is to improve diagnostic efficiency of clinical study by setting up guidelines for more precise examination with a comparative analysis of signal intensity and image distortion depending on the location of X axial of object when performing magnetic resonance diffusion weighted imaging (MR DWI) examination. We arranged the self-produced phantom with a 45 mm of interval from the core of 44 regent bottles that have a 16 mm of external diameter and 55 mm of height, and were placed in 4 rows and 11 columns in an acrylic box. We also filled up water and margarine to portrait the fat. We used 3T Skyra and 18 Channel Body array coil. We also obtained the coronal image with the direction of RL (right to left) by using scan slice thinkness 3 mm, slice gap: 0mm, field of view (FOV): $450{\times}450mm^2$, repetition time (TR): 5000 ms, echo time (TE): 73/118 ms, Matrix: $126{\times}126$, slice number: 15, scan time: 9 min 45sec, number of excitations (NEX): 3, phase encoding as a diffusion-weighted imaging parameter. In order to scan, we set b-value to $0s/mm^2$, $400s/mm^2$, and $1,400s/mm^2$, and obtained T2 fat saturation image. Then we did a comparative analysis on the differences between image distortion and signal intensity depending on the location of X axial based on iso-center of patient's table. We used "Image J" as a comparative analysis programme, and used SPSS v18.0 as a statistic programme. There was not much difference between image distortion and signal intensity on fat and water from T2 fat saturation image. But, the average value depends on the location of X axial was statistically significant (p < 0.05). From DWI image, when b-value was 0 and 400, there was no significant difference up to $2^{nd}$ columns right to left from the core of patient's table, however, there was a decline in signal intensity and image distortion from the $3^{rd}$ columns and they started to decrease rapidly at the $4^{th}$ columns. When b-value was 1,400, there was not much difference between the $1^{st}$ row right to left from the core of patient's table, however, image distortion started to appear from the $2^{nd}$ columns with no change in signal intensity, the signal was getting decreased from the $3^{rd}$ columns, and both signal intensity and image distortion started to get decreased rapidly. At this moment, the reagent bottles from outside out of 11 reagent bottles were not verified from the image, and only 9 reagent bottles were verified. However, it was not possible to verify anything from the $5^{th}$ columns. But, the average value depends on the location of X axial was statistically significant. On T2 FS image, there was a significant decline in image distortion and signal intensity over 180mm from the core of patient's table. On diffusion-weighted image, there was a significant decline in image distortion and signal intensity over 90 mm, and they became unverifiable over 180 mm. Therefore, we should make an image that has a diagnostic value from examinations that are hard to locate patient's position.