• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.151-155
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• 2010

Primary hepatic lymphoma is extremely rare, representing less than 1% of all extranodal lymphomas. We report MR imaging features and pathologic correlation of a case of primary hepatic lymphoma. MR images showed a large lobulated mass with gradual contrast enhancement, resembling intrahepatic cholangiocarcinoma. However, both hepatobiliary phase image obtained 20 minutes after injection of hepatocyte specific contrast agent and diffusion-weighted image demonstrated characteristic three layered pattern representing viable lymphoma in the outer layer, tumor necrosis in the middle layer and necrotic hepatic parenchyma in the center.

• Journal of the Korean Society of Radiology
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• v.85 no.2
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• pp.445-450
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• 2024

Gastric metastasis (GM) from cervical cancer is extremely rare, and only a few cases have been reported in the English literature. Gastric-type mucinous adenocarcinomas (GAS) of the uterine cervix are rare. GAS is an aggressive cancer commonly found in advanced stages; however, GM has not been reported. This study presents a rare case of GM from GAS of the uterine cervix in a 61-year-old female and describes the radiological findings of both the GM and cervical mucinous adenocarcinoma. GM appeared as a poor enhancing submucosal mass. The cervical mucinous adenocarcinoma appeared as an infiltrating mass with poor contrast enhancement. It exhibited mildly high and low signal intensities on the diffusion-weighted image and apparent diffusion coefficient map, respectively. This case is extremely rare and challenging to diagnose; however, if cervical cancer is an human papillomavirus-independent GAS type and a submucosal lesion is found in the stomach, the possibility of metastasis with a pattern similar to our case could be considered.

• Journal of the Korean Society of Radiology
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• v.4 no.3
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• pp.13-18
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• 2010

Purpose : Diffusion tensor imaging(DTI) allows the visualization of fiber tract damage in patients with cerebral infarction. The purpose of this study is to evaluate the correlation between degree of NIH stoke scale and fractional anisotropy (FA) in patient with cerebral infarction. Material and Methods : 16 patients aged 36~77 years(male : 11, female : 5, mean age : 61y), diagnosed cerebral infarction by diffusion weighted imaging(DWI), underwent 24 directional diffusion tensor imaging(DTI). Patients had the DTI taken within 3days of stroke onset. Comparison of DWI, FA value on DTI were measured infarcted area and counter part of specific region of interest (ROI). And evaluation of differences between clinically improved patient group (n=9) and unimproved patient group (n=7) until 2 week follow up after development of cerebral infarction. Clinical status was scaled by NIH stroke scale. Results : Quantitative measurements of FA confirmed statistically the significant diffusion changes in the infarct compared with the matched-counter part region. In DWI, the infarcted area shows high signal intensity, however FA value on DTI was lower than normal brain parenchyma. The FA value of clinically improved patient by NIH stroke scale was 0.49, and the value of contralateral normal brain parenchyma was 0.41. On the contrary, FA value of infarcted area shows about 15% lower than normal brain parenchyma. But, the FA value of unimproved patient by NIH stroke scale represents a half those of contralateral normal brain parenchyma (0.28 on infarcted area vs. 0.56 on normal brain parenchyma). So, the FA value of unimproved patient group was considerably less than those of improved. Conclusion : It is concluded that the unimproved patient group after cerebral infarction showed much less FA value than that of normal brain parenchyma. The FA value of DTI may be one of the useful parameter to predict outcome of cerebral infarction patients.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.144-148
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• 2013

Although most cases of posterior reversible encephalopathy syndrome (PRES) are reversible, irreversible lesions as a form of hemorrhage or infarction have been described. PRES as a complication of systemic lupus erythematosus (PRES-SLE) is associated with hypertension or use of immunosuppressive agents. We present a case of recurrent atypical PRES-SLE, which showed restricted diffusion in the first manifestation of SLE, resulted in parenchymal hemorrhagic transformations in the recurrent episode.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.43 no.1 s.307
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• pp.9-16
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• 2006

This Paper proposes an adaptive error diffusioThis paper proposes an adaptive error diffusion algorithm for text enhancement followed by an efficient text segmentation that uses the maximum gradient difference (MGD). The gradients are calculated along with scan lines, and the MGD values are filled within a local window to merge the potential text segments. Isolated segments are then eliminated in the non-text region filtering process. After the left segmentation, a conventional error diffusion method is applied to the background, while the edge enhancement error diffusion is used for the text. Since it is inevitable that visually objectionable artifacts are generated when using two different halftoning algorithms, the gradual dilation is proposed to minimize the boundary artifacts in the segmented text blocks before halftoning. Sharpening based on the gradually dilated text region (GDTR) prevents the printing of successive dots around the text region boundaries. The error diffusion algorithm with edge enhancement is extended to halftone color images to sharpen the tort regions. The proposed adaptive error diffusion algorithm involves color halftoning that controls the amount of edge enhancement using a general error filter. The multiplicative edge enhancement parameters are selected based on the amount of edge sharpening and color difference. Plus, the additional error factor is introduced to reduce the dot elimination artifact generated by the edge enhancement error diffusion. By using the proposed algorithm, the text of a scanned image is sharper than that with a conventional error diffusion without changing background.

• Investigative Magnetic Resonance Imaging
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• v.14 no.1
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• pp.69-73
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• 2010

Cerebral fat embolism (CFE) is a rare, albeit potentially lethal complication of long-bone fractures. All trauma patients who are initially lucid and subsequently experience mental status deterioration should undergo immediate evaluation of possible CFE. In the present case, magnetic resonance imaging (MRI) was the most sensitive technique for the diagnosis of CFE, particularly the use of diffusionweighted images (DWI). The authors present this case to report a pathophysiologybased interpretation of the MR characteristics and treatment of CFE.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.30-38
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• 2001

Background: The purpose of this study was to evaluate the usefulness of diffusion-weighted magnetic resonance imaging for monitoring the response to radiation therapy in metastatic bone marrow of the spines. Materials and Methods: Twenty-one patients with metastatic bone marrow of the spines were examined with MRI. Diffusion-weighted and spin-echo MRI were performed in 10 patients before and after radiation therapy with or without systemic chemotherapy, and performed in 11 patients after radiation therapy alone. Follow up spin-echo and diffusion-weighted MRI were obtained at 1 to 6 months after radiation therapy according to patients' condition. The diffusion-weighted imaging sequence was based on reversed fast imaging with steady-state precession (PSIF). Signal intensity changes of the metastatic bone marrows before and after radiation therapy on conventional spin-echo sequence MRI and diffusion-weighted MRI were evaluated. Bone marrow contrast ratios and signal-to-noise ratios before and after radiation therapy of diffusion- weighted MRI were analyzed. Results: All metastatic bone marrow of the spinal bodies were hyperintense to normal bone marrow of the spinal bodies on pretreatment diffusion-weighted MRI and positive bone marrow contrast ratios(p<0.001), and hypointense to normal spinal bodies on posttreatment diffusion-weighted MRI and negative bone marrow contrast ratios(p<0.001). The signal to noise ratios after treatment decreased comparing with those of pretreatment. Decreased signal intensity of the metastatic bone marrows on diffusion-weighted MRI began to be observed at average more than one month after the initiation of the radiation therapy. Conclusion: These results suggest that diffusion-weighted MRI would be an excellent method for monitoring the response to therapy of metastatic bone marrow of the spinal bodies, however, must be investigated in a larger series of patients with longer follow up period.

• Korean Journal of Digital Imaging in Medicine
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• v.11 no.2
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• pp.51-57
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• 2009

The purpose of this study would evaluate if having clinical effects on diffusion image with quantitative analysis through ADC values of brain's normal tissue and lesions before and after contrast injections using a 3.0T. From November in 2007 until December in 2008, a total of 32 patient was performed on 3.0T(Signa Excite, GE Medical System, USA) with the normal or lesions in the patient who requests diffusion weighted image with 8channel head coil. The pulse sequence was used with spin echo EPI(TR: 10000msec, TE: 72.2 msec, Matrix: 128*128, FOV: 240 mm, NEX: 1, diffusion direction: 3, b-value: 1000). Measurement results of ADC values on lesions, CSF, white matter, gray matter, lesions after contrast injection were measured less 75% than before contrast injection, infarction: 100%, CSF: 78%(high), white matter: 71.4%(low), gray matter: 50%(high, low). The results of paired t-test on the deference of ADC values which statically is significant in three(lesions, CSF, white matter)regions except for white matter(p<0.05). Quantitative analysis of lesions, CSF, white matter, gray matter have difference on all regions. ADC values were low in lesions and white matter, normal CSF after contrast injection commonly is high than before contrast injection, ADC values which white matter were high and low (50:50) after contrast injection. 3.0T diffusion weighted image clinically supposed that performing DWI examination after contrast injection was not desirable because of having effects on brain tissue.

• 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.

• The Journal of the Korea Contents Association
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• v.21 no.5
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• pp.22-35
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• 2021

The unprecedented pandemic caused by the COVID-19 has led to a massive global public health campaign to slow the spread of the virus. Thus, this study examines the importance of individual's prevention behavior intention by adapting health belief model(HBM). In addition, we added social variables to understand the prevention behavior better considering the situation in which collective behaviors are important. The online survey results(N=298) showed that higher level of perceived severity, perceived susceptibility, perceived benefits, perceived peril, perceived social norms and lower level of perceived responsibility led to higher prevention behavior intention. Peril was the most influential factor among all the variables. In addition, perceived severity and social norms followed after that. Additional analysis also implied that socio-HBM model we proposed better explained the prevention behavior intention than traditional HBM.