1.Magnetization Transfer Ratio of Brain Tissue: Normal Value and Effect of TR/TE.
Tae Sub CHUNG ; Eun Kee JEONG ; Tae Joo JEON ; Duk Jae KIM ; Hyuk Woo KWON
Journal of the Korean Radiological Society 1995;32(4):535-540
PURPOSE: Magnetization transfer imaging(MTI) is a new imaging contrast technique. Our MT pulse sequence is designed as fixed time interval between echo and MT pulse. This study was peformed to evaluate the influence of variations in TR/TE on MTR in T1 weighted image of normal brain tissue on this kind of MT pulse sequence. MATERIALS AND METHODS: Seven healthy volunteers in twenties of age as the objectives, MRI was taken under various TR/TE(TR/TE ;700/14, 650/14, 750/14, 700/20 and 1500/20 msec). MTR was calculated from signal intensities measured at the same point in both pre and post MT images and statisticslly analyzed. The MR imager used in this study was 1.0T Magnetom 42SP(Siemens, Erlangen, Germany) and the parameters of additional MT pulse sequence were offset 1000Hz and bandwidth 250Hz, and posteriorly located to echo with 7.7 msec fixed interval. Offset of this MT pulse was variable. RESULT: In white matter of brain tissue from a normal person, MTR was 34-39%(average 37%) for TR and TE of 700/14 in T1WI and 33-36%(average 35%) for TR/TE of 650/14, and 34-38%(average 35%) for TR/TE of 750/14 which showed no statistical difference. However, in case of 1500/20 of TR/TE, MTR was 26-28%(average 26%) which is statistically significant. With TR/TE of 700/14 as the standrd value, the MTR of gray and white matter were 37% and 29% respectively, showing a definite difference of statistical means. Signal from CSF in ventricles is rarely influenced by MT pulse. CONCLUSION: Conclusively, a subtle variation in TR/TE in T1WI has little influence on MTR but wide range of variation in TR/TE as in proton density image induces significant difference in MTR on this kind of MT pulse sequence. Therefore, the exchangeable usage of MTR data would be possible in narrow range of TR/TE change but difficult in wide range of variation.
Brain*
;
Healthy Volunteers
;
Humans
;
Magnetic Resonance Imaging
;
Protons
;
Reference Values*
2.MRI Study about the Early Changes of Lumbar Disk Degeneration using Magnetization Transfer Contrast (MTC).
Young Soo KIM ; Tae Sub CHUNG ; Tae Hoon KIM ; Eun Kee JEONG ; Hyuk Woo KWON
Journal of the Korean Radiological Society 1995;32(6):865-870
PURPOSE: To obtain magnetization transfer ratio(MTR) of the annulus fibrosus and nucleus pulposus and to assess the feasibility of utilizing the changes of these MTRs as an early indicator of disk degeneration. MATERIALS AND METHODS: MR images of lumbar spine with magnetization transfer(MT) technique in 42 patients were obtained. spin echo techniques (600/14) with same TR/TE with 1KHz off-resonance saturation were employed in 1.0T MR system. MTRs were calculated in two regions, anterior annulus fibrosus and nucleus pulposus, and the results were compared between the normal and degenerative disks, from grade I to IV, on T2-weighted images. RESULTS: MTRs of the nucleus pulposus were 17.6% in the normal disks, and 26.7%, 28.4%, 29.1%, 29.7% in degenerative disks, from grade I to IV, respectively, with a significant difference(P<0.05). On the other hand, MTRs in the annulus fibrosus were 30.2% in the normal disks and 31.5%, 33.2%, 32.1% and 35.6% in degenerative disks, from grade I to IV, respectively, without significant difference. CONCLUSION: Since MTRs are significantly higher in degenerative nucleus pulposus than those of the normal disks, increased MTRs in the nucleus pulposus can be used as an early sign of the degeneration of the nucleus pulposus.
Hand
;
Humans
;
Intervertebral Disc Degeneration*
;
Magnetic Resonance Imaging*
;
Spine
3.A case of congenital tuberculosis.
Mee Hye KIM ; Hyuk Choul KWON ; Young Il PARK ; Sang Woo KIM
Journal of the Korean Pediatric Society 1985;28(2):169-173
No abstract available.
Tuberculosis*
4.The Morphometric Study on Cruciate and Patellar Ligaments in Korean Adults
Dong Wook KIM ; Kwon Jae ROH ; Woo Kyung YOO ; In Hyuk CHUNG
The Journal of the Korean Orthopaedic Association 1995;30(5):1210-1215
In the endoscopic one-incision anterior cruciate ligament(ACL) reconstruction, placing the graft's tendon-bone interface flush with the intraarticular femoral tunnel results in frequent distal graft protrusion. On the contrary, we occasionally found that the intraarticular posterior cruciate ligament(PCL) length was longer than patellar tendon length and had a great difficulty in performing the endoscopic one-incision technique of PCL reconstruction. The purpose of this study is to get a certain guideline in the endoscopic one-incision technique of cruciate ligament reconstruction by measuring intraarticular distance of ACL, PCL and patellar tendon and by measuring distance between the insertion of pes anserinus and medial tibial plateau in 19 cadaveric knees. The results were as follows; 1. The average patellar tendon length was 36.2±4.7mm(range 24.7-45.0). 2. The average ACL length was 23.7±3.9mm(range 16.5-30.3). 3. The average PCL length was 32.7±3.8mm(range 25.4-41.0). 4. The average distance between the insertion of pes anserinus and medial tibial plateau was 38.3±5.4mm(range 27.2-53.6). Clinical Relevance: Since Korean patellar tendon is shorter than Caucasian's and intraarticular distance of ACL is same as Caucasian's, graft-tunnel mismatch doesn't seem to be a major problem with the accurate technique of the endoscopic one-incision ACL reconstruction in Korean patients. It is possible to interfere with the pes anserinus if the length of the tibial tunnel is needed more than 44.8 mm, It is very difficult to perform an endoscopic one-incision PCL reconstruction if the length of patellar tendon is less than 35mm because intraarticular distance of PCL is sometimes longer than patellar tendon in such cases.
Adult
;
Cadaver
;
Humans
;
Knee
;
Ligaments
;
Patellar Ligament
;
Transplants
5.Pathological Properties of Cryptococcus pseudolongus on the Mycelia and Fruit Body of Lentinula edodes
Hyuk Woo KWON ; Seong Hwan KIM
Mycobiology 2021;49(2):173-182
Recently, Cryptococcus pseudolongus has been reported as a new pathogen of shiitake (Lentinula edodes). However, its pathological properties are not much known. To further understand its impact on the mushroom, we investigated the pathogen’s interactions with the mycelium of shiitake, histopathological properties, host range, and sensitivity to diverse antifungal agents. The strain C. pseudolongus DUCC 4014 inhibited the mycelial growth of L. edodes strain (cultivar Sanjo 701ho) and caused browning in the mycelia confronted with the yeast on PDA. Spray inoculation of the yeast caused an abnormal browning symptom on the cap and/or gills of three shiitake cultivars grown on sawdust media in vinyl bags.Scanning electron microscopic images of the abnormally browned parts of shiitake fruit body illustrated that mushroom tissues were loosed and dispersed in the middle and edge of the cap and the arrangement of basidiospores borne on basidia in the gills was disturbed compared to those of normal shiitake fruit body. Spray inoculation also led to developing abnormal browning on the harvested fruit body, indicating C. pseudolongus could be a problem during mushroom storage. But the yeast was not able to induce abnormal browning on mushrooms of Pleurotus ferulae, Pleurotus fostreatus, and Agaricus bisporus. But it induced browning only on button mushroom (A. bisporus) when they were inoculated after wounding. Tests with 16 kinds of fungicides revealed that the cell growth of C. pseudolongus could be inhibited by benzalkonium chloride at MIC 7 lg/ml and benomyl at MIC 3 lg/ml.
6.Pathological Properties of Cryptococcus pseudolongus on the Mycelia and Fruit Body of Lentinula edodes
Hyuk Woo KWON ; Seong Hwan KIM
Mycobiology 2021;49(2):173-182
Recently, Cryptococcus pseudolongus has been reported as a new pathogen of shiitake (Lentinula edodes). However, its pathological properties are not much known. To further understand its impact on the mushroom, we investigated the pathogen’s interactions with the mycelium of shiitake, histopathological properties, host range, and sensitivity to diverse antifungal agents. The strain C. pseudolongus DUCC 4014 inhibited the mycelial growth of L. edodes strain (cultivar Sanjo 701ho) and caused browning in the mycelia confronted with the yeast on PDA. Spray inoculation of the yeast caused an abnormal browning symptom on the cap and/or gills of three shiitake cultivars grown on sawdust media in vinyl bags.Scanning electron microscopic images of the abnormally browned parts of shiitake fruit body illustrated that mushroom tissues were loosed and dispersed in the middle and edge of the cap and the arrangement of basidiospores borne on basidia in the gills was disturbed compared to those of normal shiitake fruit body. Spray inoculation also led to developing abnormal browning on the harvested fruit body, indicating C. pseudolongus could be a problem during mushroom storage. But the yeast was not able to induce abnormal browning on mushrooms of Pleurotus ferulae, Pleurotus fostreatus, and Agaricus bisporus. But it induced browning only on button mushroom (A. bisporus) when they were inoculated after wounding. Tests with 16 kinds of fungicides revealed that the cell growth of C. pseudolongus could be inhibited by benzalkonium chloride at MIC 7 lg/ml and benomyl at MIC 3 lg/ml.
7.Ruptured Saccular Aneurysm Arising from Fenestrated Proximal Anterior Cerebral Artery : Case Report and Literature Review.
Woo Keun KWON ; Kyung Jae PARK ; Dong Hyuk PARK ; Shin Hyuk KANG
Journal of Korean Neurosurgical Society 2013;53(5):293-296
The aneurysm arising from fenestrated proximal anterior cerebral artery (ACA) is considered to be unique. The authors report a case of a 59-year-old woman who presented with a subarachnoid hemorrhage (SAH) secondary to a ruptured aneurysm originating from the fenestrated A1 segment of right ACA. The patient had another unruptured aneurysm which was located at the right middle cerebral artery bifurcation. She was successfully treated with surgical clipping for both aneurysms. From the previously existing literatures, we found 18 more cases (1983-2011) of aneurysms associated with fenestrated A1 segment. All cases represented saccular type of aneurysms, and 79% of the patients had SAH. There were three subtypes of the fenestrated A1 aneurysms depending on the anatomical location, relative to the fenestrated segment. The most common type was the aneurysms located on the proximal end of fenestrated artery (82%). Azygos ACA and hypoplastic A1 were frequently accompanied by the aneurysm (33% and 31%, respectively), and multiple aneurysms were shown in three cases (16%). Considering that fenestrated A1 segment is likely to develop an aneurysm, which has high risk of rupture, early management may benefit patients with aneurysms accompanied by fenestrated proximal ACA.
Aneurysm
;
Aneurysm, Ruptured
;
Anterior Cerebral Artery
;
Arteries
;
Female
;
Humans
;
Intracranial Aneurysm
;
Middle Cerebral Artery
;
Rupture
;
Subarachnoid Hemorrhage
;
Surgical Instruments
8.Microstructural Change of Implant Surface conditioned with Tetracycline-HCl: SLA and TB surface implant.
Jung A WOO ; Yeek HERR ; Young Hyuk KWON ; Joon Bong PARK ; Jong Hyuk CHUNG
The Journal of the Korean Academy of Periodontology 2005;35(4):921-937
Mechanical and chemical methods are the two ways to treat the implant surfaces. By using mechanical method, it is difficult to eliminate bacteria and by-products from the rough implant surface and it can also cause the structural change to the implant surface. Therefore, chemical method is widely used in order to preserve and detoxicate the implant surface more effectively. The purpose of this study is to evaluate the effect of tetracylcline-HCl on the change of implant surface microstructure according to application time. Implants with pure titanium machined surface, SLA surface and TiO2blasted surface were used in this study. Implant surface was rubbed with sponge soaked in 50mg/ml tetracycline - HCl solution for 1/2 min., 1 min., 1 1/2 min., 2 min., and 2 1/2min. respectively in the test group and with no treatment in the control group. The sponge was soaked in every 30 seconds. Then, the specimens were processed for scanning electron microscopic observation. Based upon the analysis of photographs by three dentists who are not related with this study, the results were obtained as follows; 1. In the pure titanium machined surfaces, the control specimen showed a more or less rough machined surface composed of alternating positive and negative lines corresponding to grooves and ridges. After treatment, machining line was more pronounced for the control specimens. but in general, test specimens were similar to control. 2. In the SLA surfaces, the control specimen showed that the macro roughness was achieved by large-grit sandblasting. Subsequently, the acid-etching process created the micro roughness, which thus was superimposed on the macro roughness. Irrespective of the application time of 50mg/ml tetracycline - HCl solution, in general, test specimens were similar to control. 3. In the TiO2blasted surfaces, the control specimen showed the rough surface with small pits. The irregularity of the TiO2blasted surfaces with 50mg/ml tetracycline - HCl solution was lessened and the flattened areas got wider after 1 minute.
Bacteria
;
Dentists
;
Humans
;
Porifera
;
Tetracycline
;
Titanium
9.The Usefulness of Thymic Size at Birth as a Predictor of Bronchopulmonary Dysplasia.
Sun Young LEE ; Woo Kyeong CHOI ; Hyuk Po KWON ; Dong Jin LEE ; Min Hyuk RYU
Journal of the Korean Society of Neonatology 2004;11(2):185-191
PURPOSE: Recent studies show that chorioamnionitis has an important role in the pathogenesis of bronchopulmonary dysplasia(BPD) and it induces thymic involution. The purpose of this study is to test the usefulness of thymic size at birth as a predictor of BPD. METHODS: This study was conducted on 91 very low birth weight infants of <1, 500 g with mean gestational age of 29.3 weeks and mean birth weight of 1, 161 g who were admitted at NICU of Dong Kang General Hospital for past 4 years of whom 21 infants had BPD. Thymic size was measured on routine chest radiographs taken in the first 3 hours after birth and measured as the ratio between the width of the cardiothymic shadow at the level of the carina and that of the thorax at the costophrenic angles (CT/ T). RESULTS: Correlation of thymic size with gestational age was statistically significant (P=0.003). CT/T of BPD group was smaller than that of non-BPD group (0.27+/-0.06, 0.33+/-0.07, respectively, P<0.01). A significant positive correlation between small thymus at birth and BPD was detected (P=0.003, odds ratio, 21.7), but not in other disease groups. CONCLUSIONS: We concluded that a small thymus at birth on the chest radiograph could be used as an early predictive parameter of the BPD.
Birth Weight
;
Bronchopulmonary Dysplasia*
;
Chorioamnionitis
;
Female
;
Gestational Age
;
Hospitals, General
;
Humans
;
Infant
;
Infant, Newborn
;
Infant, Premature
;
Infant, Very Low Birth Weight
;
Odds Ratio
;
Parturition*
;
Pregnancy
;
Radiography, Thoracic
;
Thorax
;
Thymus Gland
10.Radiologic Evaluation of Intraabdomenal Masses in Childhood.
Hyuk Po KWON ; Woo Mok BYUN ; Mi Soo HWANG ; Son Yong KIM ; Jae Chun CHANG ; Bok Hwan PARK
Yeungnam University Journal of Medicine 1988;5(1):33-42
The abdominal tumors in children are different from those of adult. These tumors are the third most common one, preceded by leukemia and brain tumors, in children under 15 years. X-ray examination is the most important method among diagnostic approaches. The role of diagnostic imaging is to identify the precise anatomic location and extent of pathologic process with the minimal number of imaging procedures. 23 cases of abdominal tumors were reviewed in respect of age incidence, site of origin, radiologic findings. The results are briefly summarized as follows: 1. Neuroblastoma was the most common (6 cases) and wilm's tumor (5 cases), choledocal cyst (4 cases), ovarian mass (3 cases), hydronephrosis (2 cases), were descending order in frequency. 2. The most common site was retroperitoneum (60%) Kidney was the single most common site of origin. 3. Radiologic findings. The most common findings of plain radiography was ill defined soft tissue mass and this method was helpful in the presence of calcification especially in neuroblastoma. Ultrasonographic pattern was anechoic (cystic), echoic or mixed pattern, but this method provide less precise anatomical details, nevertheless Ultrasonography was particularly useful imaging modality for the pediatric abdominal tumors. IVP findings were renal displacement, caliceopelvic system distortion or nonvisualization of kidney, these information was helpful in determining the location of tumors. CT scan showed homogenous or inhomogeneous, cystic or solid, mass with their anatomic location. 4. Ultrasonography was the most widely used specific diagnostic method, but had limited value in detecting the anatomic location of tumors. CT scan was superior to ultrasound for determining the extent of tumors.
Adult
;
Brain Neoplasms
;
Child
;
Diagnostic Imaging
;
Humans
;
Hydronephrosis
;
Incidence
;
Kidney
;
Leukemia
;
Methods
;
Neuroblastoma
;
Radiography
;
Tomography, X-Ray Computed
;
Ultrasonography
;
Wilms Tumor