• Journal of the Korean Society of Radiology
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• v.81 no.1
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• pp.190-196
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• 2020

Xanthogranulomatous inflammation is a rare inflammatory reaction, characterized by lipid-laden macrophages, known as xanthomas, in histopathologic examination. Aggressive xanthogranulomatous inflammation often manifests as local infiltration but does not affect distant organs unless combined with rare systemic diseases. We report a case of focal xanthogranulomatous pyelonephritis (XGP) associated with severe xanthogranulomatous cholecystitis. Focal XGP was suspected in radiologic examination that showed a cystic lesion with an infiltrative margin, which were surgically resected and confirmed in pathologic examination. To our knowledge, this is the first report of focal xanthogranulomatous pyelonephritis associated with xanthogranulomatous cholecystitis. Moreover, we found peripheral hypointensity around the cystic lesion in the T2-weighted image, probably reflecting hemorrhage and fibrosis of the xanthogranulomatous inflammation.

• Journal of the Korean Society of Radiology
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• v.82 no.5
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• pp.1186-1195
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• 2021

Purpose In the adult emergency department of a university hospital, we investigated the frequency of major discrepancies between the preliminary reports by radiology residents and the final reports by certified radiologists. Materials and Methods Based on CT and MRI scans obtained between December 2016 and November 2019, we selected cases with diagnoses or treatment plans that could be changed due to discrepancies between preliminary and final reports and classified them by the type of discrepancy. We also examined the distributions of the major discrepancies and stratified them by residents' working time zone, experience, and subspecialty. Results Based on the 72137 preliminary reports evaluated, 1348 tests (1.9%) showed major discrepancies. Most of the major discrepancies were false negatives (72.0%), followed by misdiagnosis (26.3%) and false positives (1.7%). Acute findings (87.2%) were more common than non-acute findings (12.8%). The major discrepancy rate increased toward the second half of the 24-hour shift, with the highest rate of 2.9% occurring between 2 am and 4 am. The major discrepancy rate did not vary with experience, and it varied from 0.6% to 4.5% for each subspecialty. Conclusion The major discrepancy rate was less than 2%, and it increased with longer working hours during a 24-hour shift.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.2
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• pp.55-61
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• 2013

The purpose of this study is to evaluate image blurring according to variation of the ETL and propose the clinically appropriate ETL range. SIEMENS MAGNETOM Skyra 3.0T and 20 channel head coil were used for the study. MRI phantom was kept the lines horizontally to three direction(X,Y,Z) of the coil and T1, T2 weighted images that used the fast spin echo technique acquired. The ETL with increase of 10 was applied from 10 to 80. In addition, the ETL with increase of 1 was applied in the interval statistically significant differences occurred. And T1, T2 weighted images that used the conventional spin echo technique acquired to compare image blurring of the images that used the fast spin echo technique. The slope of lattice in the images was measured using Image J 1.47v program to evaluate image blurring. And image blurring was determined by the degree of the slope. The statistical significance of both techniques was evaluated by the Kruskal-Wallis test of the SPSS 17.0v. And the correlation of the ETL and image blurring was evaluated quantitatively by regression analysis. The slope of the T1, T2 weighted images that used fast spin echo technique decreased as contrasted with conventional spin echo technique. In the result of the Kruskal-Wallis test, the T1, T2 weighted images that used fast spin echo technique made a significant difference with conventional spin echo technique. Particularly, in the Tomhane' T2 test, the T1, T2 weighted images made a significant difference from ETL 22 and 31 respectively. In the result of the regression analysis, the R-squared of the T1, T2 weighted images are 0.762 and 0.793. It is difficult to apply the long ETL in the T1 weighted image caused by the short TR and multi-slices study. Therefore, clinical impact according to variation of the ETL is very slight in the T1 weighted images. But the application of the proper ETL is demanded in T2 weighted images using the fast spin echo technique in order to prevent image blurring.

• Journal of the Korean Arthroscopy Society
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• v.10 no.1
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• pp.39-44
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• 2006

Purpose: The object of this study is to compare the Insall-Salvati ratio and Carton index between the patients who have an anterior cruciate ligament (ACL) tear and the patients who have no ACL tear. Materials and Methods: The study group included 114 patients who had an ACL tear and received arthroscopic reconstruction. The group I was acute ACL tear group, within 3 weeks after injury. The group II was chronic ACL tear group who had MRI was done after 3 weeks from injury. The group III was normal control group. We measured the Insall-Salvati ratio and Carton index on Magnetic Resonance Images (MRI) for all patients. Results: The Insall-Salvati ratio of control group was $1.02{\pm}0.12$ and Carton index of control group was $1.14{\pm}0.16$. The ACL-tear study group was $0.91{\pm}0.12\;and\;0.89{\pm}0.20$ respectively. The Insall-Salvati ratio and Caton index in ACL tear group was significantly less than those of control group. There were no significant differences in comparing with acute and chronic ACL tear group. Conclusion: Our study show that patella baja has an association with ACL tears, therefore in patients with an ACL tear who had patella baja, ideal graft for reconstruction was seriously considered.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.127-136
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• 2009

Purpose : Functional magnetic resonance imaging (fMRI) was used to assess the temporal response of neural activation in healthy subjects while they performed the Iowa Gambling Test (IGT), which utilizes decisions involving ambiguity and risk. The IGT was divided into five blocks of 20 trials; analysis showed that activity in the medial prefrontal cortex (mPFC) moves gradually from the dorsal to the ventral mPFC over the course of the IGT. These findings suggest that cognitive division of the mPFC, including the dorsal portion of the anterior cingulated cortex (ACC), plays a major role in ambiguous decision making and that the aspect of the IGT corresponding to risky decision making is associated with significant activity within the corticolimbic network strongly implicated in emotion and reinforcement. Our results also suggest that decisions made under ambiguity and decisions made under risk situations can be further divided into sub-phases based on the neural network involved.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.139-145
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• 2011

Purpose : To assess the frequency and severity of acute adverse reactions to intravenous administration of gadolinium-based contrast agents using computerized reporting system at a single large academic institution. Materials and Methods : We assessed data from electronic hospital information system from October 2008 to December 2010. Reactions were classified as mild, moderate, or severe. We compared the frequency of adverse reactions among three contrast agents (Gd-BT-DO3A, Gd-DTPA and Gd-EOB-DTPA). Results : The total number of administrated contrast agents was 33,600, and the number of administration of Gd-BT-DO3A, Gd-DTPA and Gd-EOB-DTPA were 20,824 (62%), 10,417 (31%) and 2,359 (7%), respectively. Total 39 adverse reactions were reported accounting for 0.1161% of all administrations. The incidences of adverse reactions were 0.1248% (26/39, 67%) for Gd-BT-DO3A, 0.0768% (8/39, 21%) for Gd-DTPA, and 0.2120% (5/39, 13%) for Gd-EOB-DTPA. The difference of frequencies of adverse reaction among three contrast agents was not significant. Most cases of the adverse effect were mild (35/39, 89.7%). Moderate and severe adverse reactions were encountered in two patients, respectively. Conclusion : Among Koreans, adverse effects were rare, and especially, moderate to severe adverse reactions were much rarer. There was no difference among the frequencies of adverse reactions caused by three different contrast agents.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.8 no.1
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• pp.113-122
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• 1997

The purpose of this study was to examine brain structural abnormalities in autistic children. Magnetic resonance imaging(MRI) findings in 22 male children with a DSM-Ⅲ-R diagnosis of autistic disorder and 17 non-autistic male control children were investigated. The ratio measures by lineometry was used to examine the cerebrum, midbrain, cerebellum, brain stem and ventricular system. The left to right ratio of the lateral ventricle was larger in autistic children than in controls. The pons was significantly larger in autistic children than in controls, and the cerebellum was smaller in autistic children. There were no significant differences between autistic children and controls in the symmetricity of the fontral lobe, parietal lobe, occipital lobe and temporal lobe, and in the size of the midbrain and 4th ventricle. These findings suggest that autistic disorder may be related to structural impairment of the brain.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.15 no.2
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• pp.87-92
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• 2015

Mucopolysaccharidosis (MPS) is an inherited disease entity associated with lysosomal enzyme deficiencies. MPS type 2, also known as Hunter syndrome, has a characteristic morphology primarily involving x-l inked recessive defects and iduronate-2-sulfatase gene mutation. The purpose of this case report is to provide important clues to help pediatricians identify Hunter syndrome patients earlier (i.e., before the disease progresses). A 30-month-old boy showed developmental delay and decreased speech ability. Physical examinations revealed a flat nose and extensive Mongolian spots. Brain magnetic resonance images (MRIs) showed bilateral multiple patchy T2 hyperintense lesions in the periventricular and deep white matter, several cyst-like lesions in the body of the corpus callosum, and diffuse brain atrophy, which were in keeping with the diagnosis. Based on these findings, the patient was suspected of having MPS. In the laboratory findings, although the genetic analysis of IDS (Iduronate-2-sulfatase) did not show any pathogenic variant, the enzymatic activity of IDS was not detected. We could confirm the diagnosis of MPS, because other sulfatases, such as ${\alpha}$-L-iduronidase, were detected in the normal range. Early enzymatic replacement therapy is essential and has a relatively good prognosis. Therefore, early diagnosis should be made before organ damage becomes irreversible, and brain MRIs can provide additional diagnostic clues to help distinguish the disorder.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.715-723
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• 2020

Cross-talk artifacts occur in two adjacent groups of axial imaging of lesions lumbar 4-5 and sacrum 1 in lumbar spine MRI. This causes problems in reading lesions in areas corresponding to the posterior vertebra. In this study, we are going to completely remove the cross-talk artifacts through optimal concatenation TR. The region of interested were measured by averaging them into fat (ROI1), erector spinal muscle(lateral tract: iliocostalis lumborum muscle) (ROI2), erector spinal muscle(lateral tract: longissimus muscle) (ROI3), and spinous process (ROI4). The mean signal intensity (SI) was 163.43 ± 25.08 at C4 for ROI1, ROI 2 and ROI 3 at C6, 67.89 ± 11.75 and 69.99 ± 10.91 and ROI4 at C5, respectively (p<0.000). The mean signal to noise ratio (SNR) was 135.45 ± 35.90, 56.92 ± 15.90, 58.77 ± 15.59, and 54.91 ± 118.95 for SNR 1, 2, 3 and 4 (p<0.000). The contrast-to-noise ratio (CNR) was CNR1 78.52 ± 24.11, CNR2 was 76.67 ± 24.38 and CNR3 was 80.54 ± 26.33 in concatenation 6, respectively (p<0.000). The SNR, CNR, and the most efficient concatenation TR value over time are 6, and it is considered to help reduce cross-talk artifact if this is applied to T1 axial images.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.337-346
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• 2006

Aims: The present study investigated the relationship between condylar resorption and craniofacial skeleton types(especially vertical relationships), the differences of craniofacial skeleton types between with open bite group and without open bite group, and the associations of anterior disc dislocation with or without reduction to condylar resorption with MRI. Patients selection and methods: Clinical examination, magnetic resonance imaging (MRI), panorama, lateral transcranial and lateral cephalometric radiographs in 34 patients with condylar resorption were used to investigate this relationship. Results and Conclusions: Patients with the following specific facial morphologic characteristics appear to be most susceptible to condylar resorption: (1) females were predominant, (2) patients' age ranged from 12 to 50 years old with a strong predominance for 2nd and 3rd decades, (3) patients had high mandibular plane angle and high gonial angle, (4) patients had decreased vertical height of the ramus, (5) patients had generally significant antegonial notch, (6) patients had predominance of Class I occlusal relationship with or without open bite but mandible was retruded as mean ANB 5.54 degrees, (7) condylar resorption rarely occurs in lower mandibular plane angle facial types, (8) although no statistically significant difference was found, the open bite group had a tendency more hyperdivergent skeletal pattern than the non open bite group, and (9) imaging demonstrates from small resorbing condyles to idiopathic condylar resorption and TMJ articular disc dislocations. Thus, morphologic features of patients with vertical discrepancies may represent a risk factor for the development of condylar resorption.