• Journal of the Korean Society of Radiology
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• v.82 no.4
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• pp.953-958
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• 2021

High-altitude cerebral edema (HACE) is a potentially fatal neurological syndrome that develops in persons traveling to a high altitude. We report the case of a 49-year-old male who had traveled to a high altitude, and lost consciousness for a few hours. Susceptibility-weighted images revealed multiple, fine black pepper like microbleeds along the corpus callosum with several microbleeds in the left frontal and parietal subcortical white matter. The T2-weighted images did not show any abnormal signal intensities along the corpus callosum. The diffusion-weighted images revealed small nodular high signal intensities in the basal ganglia. This report describes the atypical radiologic findings of HACE showing multiple microbleeds along the corpus callosum, without abnormal high-signal intensity on T2-weighted images.

• Journal of the Korean Society of Radiology
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• v.15 no.5
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• pp.591-602
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• 2021

Acute ischemic stroke(AIS) should be diagnosed within a few hours of onset of cerebral infarction symptoms using diagnostic radiology. In this study, we evaluated the clinical usefulness of SVD and the Bayesian algorithm to measure the volume of cerebral infarction using computed tomography perfusion(CTP) imaging and magnetic resonance diffusion-weighted imaging(MR DWI). We retrospectively included 50 patients (male : female = 33 : 17) who visited the emergency department with symptoms of AIS from September 2017 to September 2020. The cerebral infarct volume measured by SVD and the Bayesian algorithm was analyzed using the Wilcoxon signed rank test and expressed as a median value and an interquartile range of 25 - 75 %. The core volume measured by SVD and the Bayesian algorithm using was CTP imaging was 18.07 (7.76 - 33.98) cc and 47.3 (23.76 - 79.11) cc, respectively, while the penumbra volume was 140.24 (117.8 - 176.89) cc and 105.05 (72.52 - 141.98) cc, respectively. The mismatch ratio was 7.56 % (4.36 - 15.26 %) and 2.08 % (1.68 - 2.77 %) for SVD and the Bayesian algorithm, respectively, and all the measured values had statistically significant differences (p < 0.05). Spearman's correlation analysis showed that the correlation coefficient of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was higher than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (r = 0.915 vs. r = 0.763 ; p < 0.01). Furthermore, the results of the Bland Altman plot analysis demonstrated that the slope of the scatter plot of the cerebral infarct volume measured by the Bayesian algorithm using CTP imaging and MR DWI was more steady than that of the cerebral infarct volume measured by SVD using CTP imaging and MR DWI (y = -0.065 vs. y = -0.749), indicating that the Bayesian algorithm was more reliable than SVD. In conclusion, the Bayesian algorithm is more accurate than SVD in measuring cerebral infarct volume. Therefore, it can be useful in clinical utility.

• 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.

• Investigative Magnetic Resonance Imaging
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• v.18 no.3
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• pp.208-218
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• 2014

Purpose : To evaluate the relationship between the speed of enhancement of hepatic hemangiomas on gadolinium-enhanced MRI and ADC values by using various parameters, including the D, f, $D^*$ and $ADC_{fit}$ on intravoxel incoherent motion (IVIM) MR Imaging. Materials and Methods: The institutional review board approved this retrospective study. A total of 47 hepatic hemangiomas from 39 patients were included (20 men and 19 women). The hemangiomas were classified into three types according to the enhancement speed of the hepatic hemangiomas on gadolinium-enhanced dynamic T1-weighted images: rapid (Type A), intermediate (Type B), and slow (Type C) enhancement. The D, f, $D^*$ and $ADC_{fit}$ values were calculated using IVIM MR imaging. The diffusion/perfusion parameters and ADC values were compared among the three types of hemangiomas. Results: Both the $ADC_{fit}$ and D values of type C were significantly lower than those of type A (P = 0.0022, P = 0.0085). However, for the f and $D^*$, there were no significant differences among the three types. On DWI with all b values (50, 200, 500 and $800sec/mm^2$), the ADC values of type C were significantly lower than those of the type A (P < 0.012). For b values with $800sec/mm^2$, the $ADC_{800}$ values of the type C hemangiomas were significantly lower than those of type B (P = 0.0021). We found a negative correlation between hepatic hemangioma enhancement type and $ADC_{50}$ (${\rho}=-0.357$, P = 0.014), $ADC_{200}$ (${\rho}=-0.537$, P = 0.0001), $ADC_{500}$ (${\rho}=-0.614$, P = 0.0001), and $ADC_{800}$ (${\rho}=-0.607$, P = 0.0001). Therefore, four ADC values of $ADC_{50}$, $ADC_{200}$, $ADC_{500}$, and $ADC_{800}$ were decreased with decreasing enhancement speed. Conclusion: Hepatic hemangiomas had variable ADCs according to the type of enhancement, and the reduced ADCs in slowly enhancing hemangiomas may be related to the reduced pure molecular diffusion (D).

• Journal of Korean Neurosurgical Society
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• v.67 no.1
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• pp.42-49
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• 2024

Objective : There is still controversy regarding whether neck remodeling stent affects the occurrence of silent embolic infarction (SEI) after aneurysm coiling. Thus, the aim of the present study is to investigate the incidence of SEI after stent-assisted coiling (SAC) using Neuroform Atlas Stent (NAS) and possible risk factors. This study also includes a comparison with simple coiling group during the same period to estimate the impact of NAS on the occurrence of SEI. Methods : This study included a total of 96 unruptured intracranial aneurysms in 96 patients treated with SAC using NAS. Correlations of demographic data, aneurysm characteristics, and angiographic parameters with properties of SEI were analyzed. The incidence and characteristics of SEI were investigated in 28 patients who underwent simple coiling during the same period, and the results were compared with the SAC group. Results : In the diffusion-weighted imaging obtained on the 1st day after SAC, a total of 106 SEI lesions were observed in 48 (50%) of 96 patients. Of these 48 patients, 38 (79.2%) had 1-3 lesions. Of 106 lesions, 74 (69.8%) had a diameter less than 3 mm. SEI occurred more frequently in older patients (≥60 years, p=0.013). The volume of SEI was found to be significantly increased in older age (≥60 years, p=0.032), hypertension (p=0.036), and aneurysm size ≥5 mm (p=0.047). The incidence and mean volume of SEI in the SAC group (n=96) were similar to those of the simple coiling group (n=28) during the same period. Conclusion : SEIs are common after NAS-assisted coiling. Their incidence in SAC was comparable to that in simple coiling. They occurred more frequently at an older age. Therefore, the use of NAS in the treatment of unruptured intracranial aneurysm does not seem to be associated with an increased risk of thromboembolic events if antiplatelet premedication has been performed well.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.5931-5936
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• 2012

This study was to evaluate the clinical usefulness of the PRESS technique based on the correlation between PRESS technique and biopsy results by applying 3.0T high magnetic field MRS technique for evaluation of non-alcoholic fatty liver disease patients. This experiment were carried out using a 3.0T magnetic resonance imaging equipment. The part data of each spectrum is taken by peak area integration. The part data of resonance peak was used to calculate relative ratio. MR spectral peak in patients with non-alcoholic fatty liver disease is from 0.9 to 1.6 ppm. According to MRS method study result, Patients with NAFLD were obtained with 94% sensitivity and 80% specificity(p=0.000). When compared to normal based on MRS and Biopsy results was valid correlation(r=0.79, p=0.04). Results for NAFLD(r=0.89, p=0.002) also showed a correlation. Therefore, PRESS technique to evaluate patients with non-alcoholic fatty liver disease, the distribution difference between normal liver and fatty liver part is significantly distinguished. Biopsy and MRS fatty liver peak ratio(%) proves high lipid over grade(r = 0.7).

• Korean Journal of Radiology
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• v.25 no.4
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• pp.351-362
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• 2024

Objective: To measure inter-reader agreement and identify associated factors in interpreting complete response (CR) on magnetic resonance imaging (MRI) following chemoradiotherapy (CRT) for rectal cancer. Materials and Methods: This retrospective study involved 10 readers from seven hospitals with experience of 80-10210 cases, and 149 patients who underwent surgery after CRT for rectal cancer. Using MRI-based tumor regression grading (mrTRG) and methods employed in daily practice, the readers independently assessed mrTRG, CR on T2-weighted images (T2WI) denoted as mrCR_T2W, and CR on all images including diffusion-weighted images (DWI) denoted as mrCR_overall. The readers described their interpretation patterns and how they utilized DWI. Inter-reader agreement was measured using multi-rater kappa, and associated factors were analyzed using multivariable regression. Correlation between sensitivity and specificity of each reader was analyzed using Spearman coefficient. Results: The mrCR_T2W and mrCR_overall rates varied widely among the readers, ranging 18.8%-40.3% and 18.1%-34.9%, respectively. Nine readers used DWI as a supplement sequence, which modified interpretations on T2WI in 2.7% of cases (36/1341 [149 patients × 9 readers]) and mostly (33/36) changed mrCR_T2W to non-mrCR_overall. The kappa values for mrTRG, mrCR_T2W, and mrCR_overall were 0.56 (95% confidence interval: 0.49, 0.62), 0.55 (0.52, 0.57), and 0.54 (0.51, 0.57), respectively. No use of rectal gel, larger initial tumor size, and higher initial cT stage exhibited significant association with a higher interreader agreement for assessing mrCR_overall (P ≤ 0.042). Strong negative correlations were observed between the sensitivity and specificity of individual readers (coefficient, -0.718 to -0.963; P ≤ 0.019). Conclusion: Inter-reader agreement was moderate for assessing CR on post-CRT MRI. Readers' varying standards on MRI interpretation (i.e., threshold effect), along with the use of rectal gel, initial tumor size, and initial cT stage, were significant factors associated with inter-reader agreement.

• Progress in Medical Physics
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• v.21 no.4
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• pp.348-353
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• 2010

The purpose of this study was to explore the potentials of a clinical 3T MRI in mouse brains and technical adaptation and optimization. T1-weighted images (T1WI), T2-weighted images (T2WI), FLAIR (Fluid Attenuated Inversion Recovery) images, Gadolinium enhanced T1-weighted images (Gd-T1WI), Diffusion weighted images (DWI) were acquired in brain of 2 mice (weight 20~25 g) with cerebral infarction by occlusion of right middle cerebral artery, 1 hour, 24 hours, 72 hours after infarction and 1 normal mouse brain using clinical 3T MRI scanner. We analyzed differentiation of striatum, ventricle, cerebral cortex, and possibility of detection of acute cerebral infarction. We could differentiate the striatum, ventricle, cerebral cortex on T2WI and on DWI, FLAIR, T1WI, the differentiation of each anatomy of brain was not definite, but acute cerebral infarction was detected on DWI of 1 hour, 24 hours, 72 hours after infarction and on T2WI, FLAIR of 24 hours, 72 hours after infarction. Clinical 3T MRI can be used in differentiation of anatomy of mouse brains and DWI can be helpul in detection of acute cerebral infarction in acute phase. With technical adaptation and optimization clinical 3T MRI can be useful tool for provide preclinical and clinical small animal studies.

• Clinical and Experimental Pediatrics
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• v.61 no.2
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• pp.64-67
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• 2018

We report the case of a 12-year-old girl who had mild encephalopathy with a reversible splenial lesion (MERS) associated with acutepyelonephritis caused by Escherichia coli. The patient was admitted with a high fever, and she was diagnosed with acute pyelonephritis based on pyuria and the results of urine culture, which detected cefotaxime-sensitive E. coli. Although intravenous cefotaxime and tobramycin were administered, her fever persisted and her C-reactive protein level increased to 307 mg/L. On day 3 of admission, she demonstrated abnormal neuropsychiatric symptoms, such as delirium, ataxia, and word salad. Magnetic resonance imaging (MRI) of the brain performed on day 4 showed marked hyperintensities in the bilateral corpus callosum and deep white matter on diffusion-weighted images, with corresponding diffusion restriction on apparent diffusion coefficient mapping. No abnormalities or pathogens were detected in the cerebrospinal fluid; however, lipopolysaccharides (LPS, endotoxin) were detected in plasma (41.6 pg/mL), associated with acute neurological deterioration. Her clinical condition gradually improved, and no neurological abnormalities were observed on day 6. Follow-up brain MRI performed 2 weeks later showed near-disappearance of the previously noted hyperintense lesions. In this patient, we first proved endotoxemia in a setting of MERS. The release of LPS following antibiotic administration might be related to the development of MERS in this patient. The possibility of MERS should be considered in patients who present with acute pyelonephritis and demonstrate delirious behavior.

• Clinical and Experimental Pediatrics
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• v.57 no.6
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• pp.264-270
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• 2014

Purpose: Acute necrotizing encephalopathy (ANE) is a fulminant disease of the brain characterized by bilateral thalamic lesions, and is prevalent among children in East Asia. The prognosis of ANE is usually poor with a high mortality rate and neurological sequelae. This study aimed to delineate the clinical characteristics and prognostic factors of ANE. Methods: We retrospectively analyzed clinical data of 399 pediatric patients with encephalitis who were admitted to Samsung Medical Center from December 1998 to March 2011. We enrolled ten patients (11 cases) with ANE and analyzed their demographic, clinical, and neuroimaging data. The location and extent of the brain regions were checked based on fluid-attenuated inversion recovery, T1-, and T2-weighted imaging findings; the presence of contrast enhancement, restricted diffusion, and hemorrhage. Results: Ten patients were identified, including one patient with two episodes. The median age of onset was 1.5 years (0.4-8.4 years). The mortality rate was 40%, and only 30% of patients survived without neurological sequelae. The definite involvement of the brainstem on brain magnetic resonance imaging was significantly correlated with mortality (P =0.04). Conclusion: Broad and extensive brainstem involvement suggested the fulminant course of ANE. Early diagnosis of ANE before brainstem involvement, through careful identification of symptoms of brain dysfunction, may be the best way to achieve better neurological outcomes.