• Korean Journal of Radiology
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• v.24 no.9
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• pp.860-870
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• 2023

Objective: The intra-parotid facial nerve (FN) can be visualized using three-dimensional double-echo steady-state water-excitation sequence magnetic resonance imaging (3D-DESS-WE-MRI). However, the clinical impact of FN imaging using 3D-DESS-WE-MRI before parotidectomy has not yet been explored. We compared the clinical outcomes of parotidectomy in patients with and without preoperative 3D-DESS-WE-MRI. Materials and Methods: This prospective, non-randomized, single-institution study included 296 adult patients who underwent parotidectomy for parotid tumors, excluding superficial and mobile tumors. Preoperative evaluation with 3D-DESS-WE-MRI was performed in 122 patients, and not performed in 174 patients. FN visibility and tumor location relative to FN on 3D-DESS-WE-MRI were evaluated in 120 patients. Rates of FN palsy (FNP) and operation times were compared between patients with and without 3D-DESS-WE-MRI; propensity score matching (PSM) and inverse probability of treatment weighting (IPTW) were used to adjust for surgical and tumor factors. Results: The main trunk, temporofacial branch, and cervicofacial branch of the intra-parotid FN were identified using 3D-DESS-WE-MRI in approximately 97.5% (117/120), 44.2% (53/120), and 25.0% (30/120) of cases, respectively. The tumor location relative to FN, as assessed on magnetic resonance imaging, concurred with surgical findings in 90.8% (109/120) of cases. Rates of temporary and permanent FNP did not vary between patients with and without 3D-DESS-WE-MRI according to PSM (odds ratio, 2.29 [95% confidence interval {CI} 0.64-8.25] and 2.02 [95% CI: 0.32-12.90], respectively) and IPTW (odds ratio, 1.76 [95% CI: 0.19-16.75] and 1.94 [95% CI: 0.20-18.49], respectively). Conversely, operation time for surgical identification of FN was significantly shorter with 3D-DESS-WE-MRI (median, 25 vs. 35 min for PSM and 25 vs. 30 min for IPTW, P < 0.001). Conclusion: Preoperative FN imaging with 3D-DESS-WE-MRI facilitated anatomical identification of FN and its relationship to the tumor during parotidectomy. This modality reduced operation time for FN identification, but did not significantly affect postoperative FNP rates.

• Korean Journal of Radiology
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• v.23 no.12
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• pp.1260-1268
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• 2022

Objective: To propose standardized MRI-proton density fat fraction (PDFF) cutoff values for diagnosing hepatic steatosis, evaluated using contemporary PDFF measuring methods in a large population of healthy adults, using histologic fat fraction (HFF) as the reference standard. Materials and Methods: A retrospective search of electronic medical records between 2015 and 2018 identified 1063 adult donor candidates for liver transplantation who had undergone liver MRI and liver biopsy within a 7-day interval. Patients with a history of liver disease or significant alcohol consumption were excluded. Chemical shift imaging-based MRI (CS-MRI) PDFF and high-speed T2-corrected multi-echo MR spectroscopy (HISTO-MRS) PDFF data were obtained. By temporal splitting, the total population was divided into development and validation sets. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance of the MRI-PDFF method. Two cutoff values with sensitivity > 90% and specificity > 90% were selected to rule-out and rule-in, respectively, hepatic steatosis with reference to HFF ≥ 5% in the development set. The diagnostic performance was assessed using the validation set. Results: Of 921 final participants (624 male; mean age ± standard deviation, 31.5 ± 9.0 years), the development and validation sets comprised 497 and 424 patients, respectively. In the development set, the areas under the ROC curve for diagnosing hepatic steatosis were 0.920 for CS-MRI-PDFF and 0.915 for HISTO-MRS-PDFF. For ruling-out hepatic steatosis, the CS-MRI-PDFF cutoff was 2.3% (sensitivity, 92.4%; specificity, 63.0%) and the HISTO-MRI-PDFF cutoff was 2.6% (sensitivity, 88.8%; specificity, 70.1%). For ruling-in hepatic steatosis, the CS-MRI-PDFF cutoff was 3.5% (sensitivity, 73.5%; specificity, 88.6%) and the HISTO-MRI-PDFF cutoff was 4.0% (sensitivity, 74.7%; specificity, 90.6%). Conclusion: In a large population of healthy adults, our study suggests diagnostic thresholds for ruling-out and ruling-in hepatic steatosis defined as HFF ≥ 5% by contemporary PDFF measurement methods.

• Korean Journal of Radiology
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• v.23 no.11
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• pp.1031-1043
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• 2022

Objective: To compare digital breast tomosynthesis (DBT) and MRI as an adjunct to full-field digital mammography (FFDM) for the preoperative evaluation of women with breast cancer based on mammographic density. Materials and Methods: This retrospective study enrolled 280 patients with breast cancer who had undergone FFDM, DBT, and MRI for preoperative local tumor staging. Three radiologists independently sought the index cancer and additional ipsilateral and contralateral breast cancers using either FFDM alone, DBT plus FFDM, or MRI plus FFDM. Diagnostic performances across the three radiologists were compared among the reading modes in all patients and subgroups with dense (n = 186) and non-dense breasts (n = 94) according to mammographic density. Results: Of 280 patients, 46 (16.4%) had 48 additional (39 ipsilateral and nine contralateral) cancers in addition to the index cancer. For index cancers, both DBT plus FFDM and MRI plus FFDM showed sensitivities of 100% in the non-dense group. In the dense group, DBT plus FFDM showed lower sensitivity than that of MRI plus FFDM (94.6% vs. 99.6%, p < 0.001). For additional ipsilateral cancers, DBT plus FFDM showed specificity and positive predictive value (PPV) of 100% in the non-dense group, but sensitivity and negative predictive value (NPV) were not statistically different from those of MRI plus FFDM (p > 0.05). In the dense group, DBT plus FFDM showed higher specificity (98.2% vs. 94.1%, p = 0.005) and PPV (83.1% vs. 65.4%; p = 0.036) than those of MRI plus FFDM, but lower sensitivity (59.9% vs. 75.3%; p = 0.049). For contralateral cancers, DBT plus FFDM showed higher specificity than that of MRI plus FFDM (99.0% vs. 96.7%, p = 0.014), however, the other values did not differ (all p > 0.05) in the dense group. Conclusion: DBT plus FFDM showed an overall higher specificity than that of MRI plus FFDM regardless of breast density, perhaps without substantial loss in sensitivity and NPV in the diagnosis of additional cancers. Thus, DBT may have the potential to be used as a preoperative breast cancer staging tool.

• Progress in Medical Physics
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• v.15 no.1
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• pp.45-53
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• 2004

SPM has been widely applied for comparison studios of the functional image data among groups of patients or individuals under different conditions and these images are from people ranging from children to adults. However, the analysis of children's brain images by using SPM can make children's brain images normalized to an adult's template image and this can result in some errors. So this study created the children's mean MR images based on the Magnetic Resonance Images of 36 normal children (age: 2～6, average age: 4.36, SD age: 1.41, M/F: 17/19), and the children's mean SPECT images by using SPECT images of 13 normal children (age: 2～6, average age: 4.80, SD age: 1.17, M/F: 10/3). We created the Korean children's brain template image, based on those mean images, and then we compared between the positions of the clusters, based on the blood flow, by normalizing ADHD children's SPECT image to Korean children's template image and SPM adult's template image. As a result of the analysis, the variation of the cluster positions was found to be a maximum of 25 ㎜. Therefore, we should be aware that we need to consider the template image and the p-value when we analyze the chlidren's brain image by using SPM.

• Investigative Magnetic Resonance Imaging
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• v.4 no.1
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• pp.52-57
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• 2000

Purpose : The purpose of this study was to investigate the pattern of cerebral response to motor tasks in patients with schizophrenia compared with normal subjects using functional MRI. Materials and methods ; Nine right handed-schizophrenic patients and six right-handed normal subjects were included. We used right hand movement as task. Series of 120 consecutive echo-planar images per section were acquired during three cycles of task and rest activations. Lateralization index of cortical response was measured and compared between patients and normal subjects. Results ; Right hand motor task was associated with greater activation in left sensorimotor cortex than the right in normal subjects. Schizophrenia patients showed relatively decreased activation in left cortex and increased activation in right cortex compared with normal subjects. In one patient, reversed lateralization was noted. Conclusion : Normal hemispheric asymmetry of cortical response to motor task was found in different pattern in schizophrenia. Our result is consistent with functional disturbance of motor circuitry in this disorder. Functional MRI will play an important role in diagnosis and research of this disorder.

• Journal of the Korean Society of Radiology
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• v.8 no.5
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• pp.255-260
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• 2014

The acute lumbar pain patients who were unavoidable to take MRI examination were made to take altered lateral recumbent position. they were also not able to control their painfulness and to be in supine position. In this study, it is supposed to increase success rate of the MRI examination through taking the altered lateral recumbent position in using spine and body matrix coil. This altered position made relaxing lumber pain and fatigue for the patients who suffered from sever lumber pain. In these reasons, it decreases the motion artifacts through correcting uncomfortable posture. As a result, qualitative analysis for the image quality was estimated to have average points of supine position A group(lateral recumbent position) of normal candidates and B group(lateral recumbent position) of the abnormal candidates who have sever pain at 4.64, 3.44, and 3.40, respectively. In conclusion, while qualitative analysis in the examination with supine position of the normal patients had significantly high points, the qualitative analysis in the examination with lateral recumbent position of the normal patients and abnormal patients who had sever lumbar pain was almost same. In addition, it was judged that radiologists' imagery interpretation had no other problems in the image evaluation of B group who had acute lumbar pain of abnormal patients. Hereupon, if this technique becomes generalized for the patients who suffer from supine position in the examination, it is supposed to be useful in medical field.

• Journal of radiological science and technology
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• v.15 no.2
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• pp.37-47
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• 1992

Magnetic Resonance Imaging(MRI) is one of the most expensive and sophisticated diagnostic tool and has been hailed as the most exciting event in medical imaging "since the introduction of X-rays", but a major disadvantage, high cost, is coming into focus especially in our country. To determine the status of distribution of MR imagers in Korea and to serve as a basic material for an efficient utilization of this Imaging machine, a retrospective survey of nationwide and regional(3 hospitals in Pusan) installations was performed. The results were as follows : 1. As of April 30, 1991, a total of 33 MRI units(24 for superconducting, 6 for permanent and 3 for resistive units) were set up and operated. 91% of the units were distributed in big cities with no one installation in 7 provinces among 12 provinces in our country. 85% of the units were imported. 2. Although 42.4% of the units were operated in Seoul, Taejeon had the best condition for the distribution of this imaging machine per population, hospital, and bed in Korea. 3. In Pusan : a) 5 units were operated with all superconducting magnet and medium magnetic field in type of machine. b) 80.1 % of the examinations were central nervous system(CNS). c) MRI examination occupied 1.4% of all radiographic examinations and the patients referred from other hospitals were composed of 23.4%% of all patients. 4. The average days under operating of MRI unit a week in Puasn were higher(5.5) than that of Seoul(4.5), but the average number of examinations and hours a week and a day, respectively(33, 8.4), was less than that of Seoul(57, 12.9). 5. The patients with positive MRI findings in a hospital(B) in Pusan was 74.5% on an average.

• Journal of radiological science and technology
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• v.41 no.5
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• pp.421-426
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• 2018

Unlike the traditional Radiological examinations, Magnetic Resonance Imaging (MRI) does not cause any harm and high levels of Radiation to the human body. Furthermore, MRI is widely used owing to its ability to adapt to different situations. However, the MRI equipment creates noises from its mechanical parts, and its magnetic bore structure can cause anxiety and claustrophobia in patients. To relieve claustrophobia, commercial refraction glasses were provided to the participants in this study, and the changes in anxiety and claustrophobia were measured. The participants were 30 volunteers with claustrophobia. To measure anxiety, the participants were asked to answer a Visual Analogue Scale (VAS) questionnaire. The physical markers of discomfort included perspiration on the forehead or hands (46.7%), mild frowning (30.3%), and leg shaking (40.1%). The subjective markers of discomfort included dizziness (2.85% in the men and 1.75% in the women). Although fear and anxiety levels were observed to be higher in the men, the difference was not significant. Hence, it was determined that both men and women felt discomfort (p >0.5). The fear coefficient was observed to decrease from 7.67 prior to wearing refraction glasses to 2.42 after wearing refraction glasses (p<0.000). In addition, use of refraction glass decreased MRI aversion from 1.97 to 1.03 (p<0.000). It can be inferred that refraction glasses are beneficial to patients undergoing MRI.

• The Journal of the Korea Contents Association
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• v.13 no.1
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• pp.294-299
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• 2013

This study has investigated the effect of intentional contact through the intercom during MRI scans on the decrease of anxiety in patients. The results obtained through the test group and control group are as follows. 1. The homogeneity of the anxiety score before the scan between the two groups was not acknowledged, hence a significant result could not be deduced. 2. Intentional contact through the intercom displayed decreasing results rational discomfort (t=-2.214, p=.031). 3. Intentional contact through the intercom displayed decreasing results of (t=-3.722, p=.000), and fear (t=-2.74, p=.009). 4. Intentional contact through the intercom displayed decreasing results of heart rate (t=-4.180, p=.000). In conclusion, the attempt to perform MRI scans with intentional contact through the intercom did not display significant effect on the blood pressure of the subject after the scan, however, displayed a decrease in objective and rational discomfort, as well as the heart rate, another vital sign. Accordingly, it is judged that intentional contact through the intercom can be used as an effective substitutive treatment method in patient care and test, as it relieves psychological tension in the patient and allows the patient to feel stability.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.4 no.1
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• pp.31-41
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• 2009

Objectives: The aim of this study was to evaluate the evolution of lumbar disc herniation in patients treated with oriental medicine. Methods: 14patients(15 cases) with lumbar disc herniation proved at MRI(Magnetic resonance imaging) underwent a follow-up MRI study. Follow-up MRI was performed $4{\sim}14$months(mean 7 months) after initial MRI. Results & Conclusions: 1. 13 cases(87%) had reduction of disc herniation. 1 showed no change in amount of disc herniation. 1 had an increase in disc herniation. 2. Comparison initial MRI with follow-up MRI showed that 2 of the herniations decreased between 0% and 25%, 3 decreased between 25% and 50%, 5 decreased between 50% and 75%, 3 decreased between 75% and 100%. The size of the herniation decreased on average by 49% in 14patients(15 cases). 3. On axial images, the proportion of the cross-sectional area of the spinal canal occupied by the herniated disc was 54.41% on the average on the initial scan, 29.65% on the follow-up scan.