• Journal of radiological science and technology
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• v.32 no.1
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• pp.17-24
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• 2009

Noise evaluation for an image has been performed by root mean square (RMS) granularity, autocorrelation function (ACF), and Wiener spectrum. RMS granularity stands for standard deviation of photon data and ACF is acquired by integration of 1 D function of distance variation. Fourier transform of ACF results in noise power spectrum which is called Wiener spectrum in image quality evaluation. Wiener spectrum represents noise itself. In addition, along with MTF, it is an important factor to produce detective quantum efficiency (DQE). The proposed evaluation method using Wiener spectrum is expected to contribute to educate the concept of Wiener spectrum in educational organizations, choose the appropriate imaging detectors for clinical applications, and maintain image quality in digital imaging systems.

• Journal of Digital Contents Society
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• v.3 no.1
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• pp.75-88
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• 2002

Radiologic images are widely used in hospitals for diagnosing and treating patients' diseases. The radiologist accurately reads radiologic images, and thus helps diagnose patients correctly. The number of radiologists is much smaller than is necessary, however. In some small or rural hospitals, there are no radiologists residing there. In these cases, correct diagnosis and treatment are infeasible. Also, radiologists are not resident at hospitals all day long. Thus, emergency patients would suffer from the absence of radiologists at night. XRay21 Inc. and Data & Knowledge Engineering Lab. at Kangwon National University have been working together since 2000 in order to alleviate the problems above. Currently, the advances of the computer and network technology make it possible to connect a lot of radiologists and hospitals together through the Internet. By fully utilizing the Internet environment, we have developed an Internet-based medical diagnosis system, thus permitting remote diagnosis of radiologic images. This paper presents the technical experiences obtained in developing the system.

• Journal of Korean Foot and Ankle Society
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• v.14 no.2
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• pp.157-160
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• 2010

Purpose: The purpose of this study is to find out the correlation factors for prognosis of calcaneal fractures. Materials and Methods: 120 cases (feet) of calcaneal fractures, all of them followed up for more than 1 year after surgical procedures, consisted of 101 men (105 feet) and 13 women (15 feet) were reviewed retrospectively. The collected clinical data were as follows : injury mechanism, surgical procedures, time to procedure, time to work and the radiologic data: Bohler angle, heel width, displacement of posterior facet. AOFAS hindfoot score and VAS score were checked. With ANOVA test and multiple regression analysis, the data processed statistically. Results: According Sanders classification, type II was 37 cases (31%), type III 66 cases (55%), and type IV 17 cases (14%). On plane radiography, the Bohler angle improved to average 28.4 degree from 5.6 degree, and the displacement of posterior facet was corrected to average 1.2 mm. AOFAS hindfoot score was checked average 81.7 points postoperatively, and the meaningful difference existed between types of Sanders classification. The Bohler angle represented the outline of the calcaneus had the better correlation with the clinical outcome of calcaneal fractures rather than the anatomical reduction of the posterior facet did. And the width of calcaneus had good correlation with the clinical score. Conclusion: We should also concern about the outline of calcaneus, the width of calcaneus and the Bohler angle representing anatomical reduction, not only the acute reduction of the posterior facet.

• Tuberculosis and Respiratory Diseases
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• v.69 no.5
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• pp.354-360
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• 2010

Background: Primary non-Hodgkin's lymphoma of the lung is a rare entity. It is represented commonly as marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) type. Although there have been a few reviews of this lymphoma, clinical features, radiologic findings, management and prognosis have not been well defined. Methods: We reviewed the medical records of 24 patients with primary pulmonary lymphoma between January 1995 and September 2008; all diagnoses had been confirmed based on pathology. Results: The median follow-up time was 42.3 months (range, 0.1~131.2 months). Five (20.8%) patients were asymptomatic, 17 (70.8%) patients had pulmonary symptoms, and the remaining 2 (8.3%) patients presented with constitutional symptoms. There were 16 (66.7%) patients with MALT lymphoma, 4 (16.7%) patients with diffuse large B-cell lymphoma and 4 (16.7%) patients with lymphoma that had not received a WHO classification. Radiologic findings of primary pulmonary lymphoma were diverse and multiple nodule or consolidation was the most common finding regardless of pathologic lymphoma type. PET scan was carried out in 13 (54.2%) patients and all lesions showed notable FDG uptake. MALT lymphoma showed a trend of better prognosis (3-year survival, 78.8% vs. 70.0%; 5-year survival, 78.8% vs. 52.5%; p=0.310) than non-MALT lymphoma. Conclusion: Primary non-Hodgkin's lymphoma of the lung occurs with nonspecific clinical features and radiologic findings. MALT lymphoma is the most common pathologic type of primary pulmonary lymphoma. This entity of lymphoma appears to have a good prognosis and in this study, there was a trend of better outcome than non-MALT lymphoma.

• Journal of Korean Foot and Ankle Society
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• v.12 no.2
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• pp.174-179
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• 2008

Purpose: We evaluated the clinical results of the intraarticular calcaneal fractures treated using Ollier approach by inexperienced orthopaedic surgeon. Materials and Methods: Between August 2003 and May 2007, Of the total 46 cases, 12 cases (9 patients) of displaced intraarticular calcaneal fracture who underwent open reduction and internal fixation using Ollier approach were evaluated. The means of age was 50.5 years. According to the Sanders classification, there was no type I case and 8 cases of type II, 1 case of type III, and 3 cases of type IV. We evaluated the treatment result by assessing radiologic parameters ($B{\ddot{o}}hler$ angle, Gissane angle, and calcaneal height/width) and clinical outcomes (VAS and AOFAS score). Results: The means of follow-up period was 25.3 months. The means of B.hler angle was improved from $2.4^{\circ}$ to $26.1^{\circ}$. Radiologic and clinical union was achieved in all cases without additional procedures. Excellent result were noted in 2 cases, good in 5 cases, fair in 4 cases, and poor in 1 case. We experienced 2 cases of minor complications; 1 case of mild wound infection and 1 case of hypoesthesia on foot dorsum. Radiologic findings of subtalar arthritis were present in 2 cases. Conclusion: Ollier approach seems to be helpful to inexperienced orthopaedic surgeons for the treatment of intraarticular calcaneal fractures in that it enables them to achieve considerable clinical outcomes without serious complications.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.483-489
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• 2011

Introduction: This study examined the cumulative resorption of implants placed in a severely atrophic mandible and analyzed the radiologic bone resorption in the marginal bone, after an autogenous bone graft including both block and particulates that had been harvested from the ramus and iliac crest. Materials and Methods: A retrospective study was performed on patients who had bone grafts for augmentation followed by implant installation in the mandible area from 2003 to 2008. Twelve patients (6 men and 6 women) who received 34 implants in the augmented sites were evaluated. Cumulative radiologic resorption around the implants was measured immediately, 3 months, 6 months and 12 months after implant installation surgery. Results: The installed implant in grafted bone showed 0.84 mm marginal bone resorption after 3 months and 50% total cumulative resorption after 1 year. The mean marginal bone resorption around the implant installed in the grafted bone was 0.44 mm after 3 months, 0.52 mm after 1 year, after which it stabilized. The implant survival rate was 97% (failed implant was 1/34). Marginal bone resorption of the installed implant in the autogenous onlay block bone grafts was 0.98 mm after 3 months, which was significantly higher than that of a particulated bone graft (0.74 mm) (P <0.05). Conclusion: An autogenous graft including block type and particulate type is a predictable procedure for the use of dental implants in a severely atrophic mandible. Implant placement in augmented areas show a relatively high survival and minimal bone loss, as revealed by a radiologic evaluation.

• Journal of Korean Neurosurgical Society
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• v.47 no.4
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• pp.278-281
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• 2010

Objective : For the treatment of osteoporotic vertebral compression fracture, percutaneous vertebroplasty (PVP) is currently widely used as an effective and relatively safe procedure. However, some patients do not experience pain relief after PVP. We performed several additional PVP procedures in those patients who did not have any improvement of pain after their initial PVP and we obtained good results. Our purpose is to demonstrate the effective results of an additional PVP procedure at the same previously treated level. Methods : We reviewed the medical records and the radiologic data of the PVP procedures that were performed at our hospital from November 2005 to May 2008 to determine the patients who had undergone additional PVP. We identified ten patients and we measured the clinical outcomes according to the visual analogue scale (VAS) score and the radiologic parameters, including the anterior body height and the kyphotic angulation. Results : The mean volume of polymethylmethacrylate injected into each vertebrae was 4.3 mL (range: 2-8 mL). The mean VAS score was reduced from 8 to 2.32. The anterior body height was increased from 1.7 cm to 2.32 cm. The kyphotic angulation was restored from 10.14 degrees to 2.32 degrees. There were no complications noted. Conclusion : The clinical and radiologic outcomes suggest that additional PVP is effective for relieving pain and restoring the vertebral body in patients who have unrelieved pain after their initial PVP. Our study demonstrates that additional PVP performed at the previously-treated vertebral levels could provide therapeutic benefit.

• Journal of Korean Neurosurgical Society
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• v.59 no.4
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• pp.374-378
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• 2016

Objective : A modified surgical technique of posterior cervical foramintomy called posterior cervical inclinatory foraminotomy (PCIF) was introduced in previous preliminary article. PCIF allows better preservation of facet joint and capsule than conventional techniques. The authors conducted a study to investigate long-term outcomes of PCIF. Methods : We retrospectively reviewed demographic, radiologic, and clinical data from the patients who underwent PCIFs at our institution. Criteria included a minimum of 48 month follow-up and PCIFs for patients with radiculopathy from foraminal stenosis (C2-T1; single or multilevel) with persistent or recurrent root symptoms despite conservative treatment for more than 3 months. Patients who had undergone previous cervical operation were excluded. The visual analogue scale (VAS) score was used for clinical follow-up, and radiologic follow-up was performed to compare the changes of cervical sagittal alignment, focal angle and disc-space height of treated segment. Results : The PCIFs were performed between April 2007 and March 2011 on 46 patients (32 males and 14 females) with a total of 73 levels affected. The average duration of follow-up was 74.4 months. Improvements in radiculopathic pain were seen in 39 patients (84.7%), and VAS score decreased from $6.82{\pm}1.9$ to $2.19{\pm}1.9$. Posterior neck pain also improved in 25 patients (71.4%) among 35 patients, and VAS score decreased from $4.97{\pm}2.0$ to $2.71{\pm}1.9$. The mean disc-space heights of treated segment were $5.41{\pm}1.03mm$ preoperatively and decreased to $5.17{\pm}1.12mm$ postoperatively. No statistically significant changes in cervical sagittal alignment, focal angle were seen during the follow-up period (Cox proportional hazards analysis and Student t-test, p>0.05). Conclusion : The PCIF is highly effective in treating patients with cervical spondylotic radiculopathy, leading to long-lasting relief in pain. Long-term radiologic follow-up showed no significant spinal angular imbalance.

• Journal of Korean Foot and Ankle Society
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• v.13 no.1
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• pp.68-74
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• 2009

Purpose: This study was designed to evaluate the results and efficacy of subtalar distraction two bone-block arthrodesis for calcaneal malunion. Materials and Methods: From January 2004 to June 2007, we operated on 8 patients (12 cases). There were 7 male patients and 1 female patient; their mean age was 42 years. 8 cases among them were operated initially. The period between initial injury and arthrodesis was 21 months. At an average follow up was 19 months. In operation, we used extensile lateral approach and arthrodesis was performed through tricortical two bone-block and cannulated screws. The Ankle-Hindfoot scale was used for clinical evaluation. In radiologic analysis, plain X-ray and CT were examined union and various parameters. Results: All cases achieved radiologic union at the final follow-up. The mean Ankle-hindfoot scale (maximum of 94 points) increased from 43.4 points preoperatively to 84 points at the final follow-up. The radiologic analysis of the pre- and postoperative standing lateral radiographs showed and average increase of 5.5 mm in talo-calcaneal height, $5.1^{\circ}$ in talocalcaneal angle, $6.1^{\circ}$ in talar declination angle and decrease of $5.7^{\circ}$ in talo-first metatarsal angle. Conclusion: The short term results of subtalar distraction two bone-block arthrodesis is promising, but longer follow-up was needed.

• Archives of Plastic Surgery
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• v.34 no.3
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• pp.358-364
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• 2007

Purpose: A life-threatening hemorrhage resulting from a severe facial fracture is rare, but it needs a prompt and aggressive treatment. Especially, a massive oronasal bleeding combined with midfacial fracture which may result from the rupture of the internal maxillary artery. With the recent advances in the radiologic intervention, its use has increased for managing these life threatening case. We reviewed its usefulness with our experiences and literatures. Methods: A retrospective review was performed to determine the usefulness of the transcatheter arterial embolization in patients with panfacial trauma. If the vital signs were unstable, cardiopulmonary resuscitation was performed. Oronasal bleeding was controlled with nasal packing and electrocautery. All injured regions were studied by radiologic study including CT. Even after primary management, if the oronasal bleeding was persistent, radiologic intervention was performed 10 patients were treated with transcatheter arterial embolization and the bleeding focus controlled by embolization with polyvinyl alcohol and gelfoam. Results: After the intervention, the vital signs became stable and there were no complications from embolization in the follow-up for 6 months. Also patients could recover through appropriate operations. Conclusion: Transcatheter arterial embolization for maxillofacial injury has many advantages for both, the doctor and the patient. First, less pain is induced than a compression device or an operation, which is another way to treat oronasal bleeding. Second, it does not need general anesthesia. And through a single procedure not only we can know the accurate bleeding point, but we can also bleeding by embolization.