• Tuberculosis and Respiratory Diseases
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• v.41 no.4
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• pp.397-404
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• 1994

Background: To decide the optimal antibiotics and application of chest tube, examination of pleural fluid is fundamental in the management of empyema. Some criteria for drainage of pleural fluid have been recommended but some controversies have been suggested. Recently, newer radiologic methods including ultrasound and computed tomography scanning, have been applied to the diagnosis and management of pleural effusions. We undertook a retrospective analysis of 30 patients with pleural effusion who had CT scans of the chest in order to apply the criteria of Light et al retrospectively to patients with loculation and to correlate the radiologic appearance of pleural effusions with pleural fluid chemistry. Method: We analyzed the records of 30 out of 147 patients with pleural effusion undergoing chest CT scans. Results: 1) Six of the pleural fluid cultures yielded gram negative organisms and three anaerobic bacterias and one Staphylococcus aureus and one non-hemolytic Streptococci. No organism was cultured in ninteen cases(63.0%). 2) The reasons for taking chest CT scans were to rule out malignancy or parenchymal lung disease(46.7%), poor response to antibiotics(40.0%), hard to aspirate pleural fluid(10.0%) and to decide the site for chest tube insertion(3.3%). 3) There was no significant correlations between ATS stages and loculation but there was a tendency to loculate in stage III. 4) There was a significant inverse relationship between the level of pH and loculation(p<0.05) but there appeared to be no relationship between pleural fluid, LDH, glucose, protein, loculation and pleural thickening. 5) In 12 out of 30, therapeutic measures were changed according to the chest CT scan findings. Conclusion: We were unable to identify any correlations between the plerual fluid chemistry, ATS stages and loculations except pH, and we suggest that tube thoracotomy should be individualized according to the clinical judgement and serial observation. All patients with empyema do not need a chest CT scan but a CT scan can provide determination of loculation, guiding and assessing therapy which should decrease morbidity and hospital stay.

• Tuberculosis and Respiratory Diseases
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• v.40 no.5
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• pp.519-531
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• 1993

Background: Lymphangioleiomyomatosis(LAM) is a very rare disease occurring in women of reproductive age and leading to progressive respiratory failure despite therapy. But the natural history of this disease is uncertain and although anti-estrogenic agents have been used for more than twenty years, it's efficacy is still in debate. This study was performed to enhance understanding of this fatal disease in Korea by examining clinical, radiological, and pathologic findings of all the previously reported cases of LAM on Korea along with four new cases of LAM whom we report in this paper. Method: Out of twlve cases of LAM previously unpublished and published in domestic papers, two cases whose diagnoses were considered doubtful after review of clinical, radiological, and pathologic findings at "Asian Congress on Lymphangioleiomyomatosis" at Kyoto, Japan in feburary of 1993 were excluded from this study. Six cases which were reported previously and four new cases of LAM whom we report in this paper were analysed for the clinical, radiological, and pathologic characteristics. Results: All ten patients were women with mean age of $33{\pm}7$. The most common symptom was exertional dyspnea and most patients had history of pneumothoraces. Pulmonary function tests showed decreased diffusing capacity. on high resolution computed tomography(HRCT), all the cases had characteristic cysts. Most of the patients did not respond to hormonal therapy. Conclusion: In women of reproductive age, presenting with dyspnea who has a history of pneumothorax, LAM should always be considered as one of the diagnostic possibilities. If suspected, HRCT should be done to look for characteristic cysts and if needed, open lung biopsy should be done to confirm the diagnosis.

• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.151-158
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• 2004

Background : When a non small cell lung caner patient at the $_cT_{1-2}N_0M_0$ stage is diagnosed with intrapulmonary nodule(s), the treatment plan and prognosis of the patient largely depend on whether the nodule is benign or malignant. In most cases, however, it is hard to conduct a biopsy on such a nodule, due to its small size. Furthermore, the predictive factors that may imply benignancy or malignancy of the nodules remain unknown. As such, the purpose of our study was to validate the incidence of malignant nodules in such cases, and find if there are any predictive factors. Methods : Chest computed tomography(CT) scans and the medical records of 444 patients, who had undergone non small cell lung cancer surgery, between July, 2001 and September, 2003, at Seoul National University Hospital, were retrospectively reviewed. Among $_cT_{1-2}N_0M_0$ non small cell lung cancer patients, with intrapulmonary nodule(s), only those cases where a CT scan or a biopsy of the nodules had been conducted, and had been followed up at intervals of more than 6 months were included. However, patients who had received chemotherapy or radiation therapy, pre- or post-operatively, or with calcified nodules, were excluded. Results : Our study group consisted of 39 patients, divided into two groups. The first group, 33 patients, had benign nodules, and the second group, 6 patients, had malignant nodules. The two groups were compared with regard to gender, age, cell type, pathologic stage, shape, size, location and number of nodules and presence of calcification around the nodules. There was no statistically significant difference between the two groups. Conclusion : The intrapulmonary nodules in non small cell lung cancer patients at the $_cT_{1-2}N_0M_0$ stage were mostly benign. Therefore, surgical treatment for such patients can be considered. Moreover, without predictive factors, pathological confirmation of the diagnosed nodules should be sought in all patients.

• Tuberculosis and Respiratory Diseases
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• v.62 no.6
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• pp.479-485
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• 2007

Background: The purpose of this study was to evaluate the differences in CT findings according to sputum smear-positive or -negative results in patients with active pulmonary tuberculosis having a single cavity. Methods: A total of 32 patients with active pulmonary tuberculosis having a single cavity on CT were classified into two groups: smear-positive (n=19) and smear-negative (n=13). The CT findings were reviewed retrospectively. The presence of consolidation, the number of lobes showing consolidation, ground-glass opacity, micronodules and nodule, the maximum diameter of the cavity, and the shape and maximum thickness of the cavity wall were assessed. Result: The maximum diameter of the cavity was $33.84{\pm}13.65mm$ and $27.08{\pm}9.04mm $ in the smear-positive and -negative groups, respectively (p>0.05). The amount of consolidation and the number of lobes with consolidation were found to be 89.5% and 30.8% (p=0.01) and $1.37{\pm}0.90$ and $0.31{\pm}0.48$ (p=0.0002) in the smear-positive and -negative groups, respectively. Consolidations in two or more lobes were only noted in 31.6% of in the sputum smear- positive group (p< 0.05). There were no other significant differences between the two groups. The sensitivity, specificity, positive and negative predictive values for the presence of consolidation were 89.5%, 69.2%, 73.9%, and 81.8%, respectively. Conclusion: While the absence of consolidation on CT may be associated with sputum smear-negative results in patients with active pulmonary tuberculosis having a single cavity, the presence of consolidation in two or more lobes on CT may be associated with spear-positive results in these patients.

• Tuberculosis and Respiratory Diseases
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• v.65 no.5
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• pp.390-395
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• 2008

Background: Since the early 1980s, interferon-alpha ($IFN-{\alpha}$) has been used as adjuvant therapy in pediatric patients with recurrent respiratory papillomatosis (RRP). However, its efficacy in adults needs to be validated. Since 2002, Samsung Medical Center's guidelines have mandated regular injection of $IFN-{\alpha}$ in patients with RRP to prevent recurrence. To evaluate these guidelines, patient data were investigated. Methods: Five patients diagnosed as having RRP by bronchoscopy and histopathology were included. After initial bronchoscopic intervention, including laser cauterization, all patients received subcutaneous injection of 6 million units of $IFN-{\alpha}$ every 2 months. Further bronchoscopic intervention was carried out as needed. Patients were regularly evaluated using bronchoscopy or computed tomography. Results: The median age of the patients was 44 years (range 13~68), and the median duration of papillomatosis was 31 years (range 1~45). Three and two patients had juvenile-onset and adult-onset disease, respectively. Two patients had a history of tracheostomy at the time of diagnosis. The median duration of $IFN-{\alpha}$ therapy was 56 months (range 12~66). Two patients showed complete remission at 12 and 36 months after $IFN-{\alpha}$ injection, respectively. The other three patients showed partial remission, and the number of laser therapy sessions was significantly reduced.Conclusion: Intermittent $IFN-{\alpha}$ injection is effective in patients with long-standing RRP and can reduce the number of laser therapy sessions required in their treatment.

• Korea Journal of Hospital Management
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• v.2 no.1
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• pp.1-21
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• 1997

In order to analyze the shifts in the volume and profits of Computed Tomography(CT) and Magnetic Resonance Imaging(MRI) utilization for a year before and after the implementation of insurance coverage for CT, this study has been undertaken examining CT and MRI cost data from 'Y' University Hospital situated in Seoul, Korea. Following are the results of this study: 1. The medical insurance payment for CT, implemented on January 1, 1996, increased CT utilization from January 1996 to April 1996 due to low insurance premiums: however, from May 1996 the number of CT cases significantly decreased as a result of strengthened medical cost reviews and the new 'Detailed standards for approval of CT' announced near the end of April 1996 by the insurer. 2. Since the implementation of insurance coverage for CT, CT fee reduction rates for reimbursements by the insurer to the hospital were 50% and 40% for January and February, respectively, and 31% and 15% for March and April. A significant point in the lowering of the reduction rate was reached in May at 11%; furthermore, since June the reduction rate fell below the average reduction rate for reimbursements for all procedures. If the 'Detailed standards for approval of CT' had been announced before the implementation of insurance coverage for CT, CT utilization would not have been so high due to the need to meet those 'standards'. In addition, loss of hospital profits resulting from the reduction for reimbursements would not have occurred. 3. The shifts in MRI utilization showed that there was no particular change with the beginning of insurance coverage for CT, and the introduction of the 'Detailed standards for approval of CT' made MRI utilization increase because MRI is free of restrictions imposed by the insurer. 4. The relationship between CT utilization and MRI utilization showed that they were supplementary to each other before insurance coverage for CT, but that CT was substituted for MRI because of strengthened medical cost reviews after t~e beginning of insurance coverage for CT. 5. The shifts in volume by patient characteristics showed that the number of inappropriate case patients, according to the insurer's "Standards for approval", decreased more than the number of appropriate case patients after the introduction of insurance coverage for CT. Therefore, the health insurance fee schemes for CT have influenced patient care. 6. The shifts in profits from CT utilization showed a net profit decrease of 31.6%. In order to match the pre-coverage profit level, 5,471 more cases would need to be seen and productivity would need to be increased by 32.7%. This profit decrease resulted from a decrease of CT utilization and low reimbursements. With insurance coverage, net profits from CT were 24.4%, and a margin of safety ratio was 39.6%. Because of the net profits and margin of safety ratio, CT utilization fees for insured appropriate cases could not be considered inappropriate. 7. The shifts in profits from MRI utilization before and after the introduction of CT coverage showed that in order to match pre-CT coverage profit levels, 2,011 more cases would need to be seen and productivity would need to be increased by 9.2%. The reasons for needing to increase the number of cases and productivity result from cost burdens created by adding new MRI units. But with CT coverage already begun, MRI utilization increased. Combined with a minor increase in the MRI fee schedule, MRI utilization showed a net profit increase of 18.5%. Net profits of 62.8% and a 'margin of safety ratio' of 43.1% for MRI utilization showed that the hospital relied on this non-covered procedure for profits. 8. The shifts in profits from CT and MRI utilization showed the net profits from CT decreased by 2.33billion Won while the net profits from MRI increased by 815.7million Won. Overall, these two together showed a net profit decrease of 1.51billion Won. The shifts in utilization showed a functional substitutionary relationship, but the shifts in profits did not show a substitutionary relationship. From these results, We can conclude that if insurance is to be expanded to include previously uncovered procedures using expensive medical equipment, detailed standards should be prepared in advance. The decrease in profits from the shifts in coverage and changes in fees is a difficult burden that should be shared, not carried by the hospital alone. Also, a new or improved fee schedule system should include revised standards between items listed and the appropriateness of the fee schedule should constantly be ensured. This study focused on one university hospital in Seoul and is therefore limited in general applicability. But it is valuable for considering current issues and problems, such as the influence of CT coverage on hospital management. Future studies will hopefully expand the scope of the issues considered here.

• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.123-133
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• 2007

Z-axis automatic tube current modulation technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare noise, and radiation dose of multi-detector row CT (MDCT) of lower extremity performed with Z-axis modulation technique of automatic tube current modulation with manual selection fixed tube current. Fifty consecutive underwent MDCT venography of lower extremity with use of a MDCT scanner fixed tube current and Z-axis automatic tube current modulation technique (10, 11 and 12 HU noise index, $70{\sim}450\;mA$). Scanning parameters included 120 kVp, 0.5 second gantry rotation time, 1.35:1 beam pitch, and 1 mm reconstructed section thickness. For each subject, images obtained with Z-axis modulation were compared with previous images obtained with fixed tube current (200, 250, 300 mA) and with other parameters identical. Images were compared for noise at five levels: iliac, femoral, popliteal, tibial, and peroneal vein of lower extremity. Tube current and gantry rotation time used for acquisitions at these levels were recorded. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with Z-axis automatic tube current modulation. Compared with fixed tube current, 2-axis modulation resulted in reduction of CTDIvol (range, $-6.5%{\sim}-35.6%$) and DLP (range, $-0.2%{\sim}-20.2%$). Compared with manually selected fixed tube current, 2-axis automatic tube current modulation resulted in reduced radiation dose at MDCT of lower extremity venography.

• Sleep Medicine and Psychophysiology
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• v.2 no.1
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• pp.73-81
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• 1995

Objective : Patients with sleep apnea should be diagnosed with polysomnography(PSG). However, it is not easy to recommend PSG for all patients suspected with sleep apnea in practice. Therefore, we tried to develop the screening test for referral of PSG. Method : 140 patients with snoring and sleep apnea syndrome were studied by the PSG. Sleep apnea questionnaire. Zung's scale for depression. Stanford Sleepiness Scale(SSS), insomnia scale and neuropsychological test were administered. Also, blood pressure, height, weight and neck circumference were measured and some histories were taken. Correlations between respiratory disturbance index(RDI) and various parameters mentioned above and discriminant coefficients of the parameters to RDI were computed. And, we investigated sensitivities of screening tests for selection of the patients with RDI above 20. Results : Using six parameters(neck circumference, systolic blood pressure before sleep, degree of alcohol drinking, frequency of breath-holding during sleep, degree of dry mouth during sleep, sleep apnea score), the patients with RDI above 20 could be discriminated in 92.8% sensitivity. In case of more than two among six parameters(neck circumference of above 40cm, systolic blood pressure of above 125mmHg, frequent alcohol drinking, frequent breath-holding during sleep, frequent dry mouth during sleep, sleep apnea score of above 35), same patients could be discriminated in 87.6% sensitivity. And, in case of more than one among four parameters(neck circumference of above 40cm. systolic blood pressure of above 125mmHg, frequent alcohol drinking, body weight of above 80kg), discrimination sensitivity was 83.5%. Conclusions : Patients with RDI above 20 could be discriminated by above parameters with high sensitivity. Therefore, the screening test using above parameters can be applied in selection of the patients with sleep apnea for PSG in practice.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5259-5264
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• 2014

Background: CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Materials and Methods: Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose ($D_{Max}$) to rectum was the highest recorded dose at one of these five points. Using the HDRplus 2.6 brachyhtherapy treatment planning system, the bladder and rectum were retrospectively contoured on the 55 CT datasets. The DVHs for rectum and bladder were calculated and the minimum doses to the highest irradiated 2cc area of rectum and bladder were recorded ($D_{2cc}$) for all individual fractions. The mean $D_{2cc}$ of rectum was compared to the means of ICRU rectal point and rectal $D_{Max}$ using the Student's t-test. The mean $D_{2cc}$ of bladder was compared with the mean ICRU bladder point using the same statistical test. The total dose, combining EBRT and HDR brachytherapy, were biologically normalized to the conventional 2 Gy/fraction using the linear-quadratic model. (${\alpha}/{\beta}$ value of 10 Gy for target, 3 Gy for organs at risk). Results: The total prescribed dose was $77.5Gy{\alpha}/{\beta}10$. The mean dose to the rectum was $4.58{\pm}1.22Gy$ for $D_{2cc}$, $3.76{\pm}0.65Gy$ at $D_{ICRU}$ and $4.75{\pm}1.01Gy$ at $D_{Max}$. The mean rectal $D_{2cc}$ dose differed significantly from the mean dose calculated at the ICRU reference point (p<0.005); the mean difference was 0.82 Gy (0.48-1.19Gy). The mean EQD2 was $68.52{\pm}7.24Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$, $61.71{\pm}2.77Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$ and $69.24{\pm}6.02Gy_{{\alpha}/{\beta}3}$ at $D_{Max}$. The mean ratio of $D_{2cc}$ rectum to $D_{ICRU}$ rectum was 1.25 and the mean ratio of $D_{2cc}$ rectum to $D_{Max}$ rectum was 0.98 for all individual fractions. The mean dose to the bladder was $6.00{\pm}1.90Gy$ for $D_{2cc}$ and $5.10{\pm}2.03Gy$ at $D_{ICRU}$. However, the mean $D_{2cc}$ dose did not differ significantly from the mean dose calculated at the ICRU reference point (p=0.307); the mean difference was 0.90 Gy (0.49-1.25Gy). The mean EQD2 was $81.85{\pm}13.03Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$ and $74.11{\pm}19.39Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$. The mean ratio of $D_{2cc}$ bladder to $D_{ICRU}$ bladder was 1.24. In the majority of applications, the maximum dose point was not the ICRU point. On average, the rectum received 77% and bladder received 92% of the prescribed dose. Conclusions: OARs doses assessed by DVH criteria were higher than ICRU point doses. Our data suggest that the estimated dose to the ICRU bladder point may be a reasonable surrogate for the $D_{2cc}$ and rectal $D_{Max}$ for $D_{2cc}$. However, the dose to the ICRU rectal point does not appear to be a reasonable surrogate for the $D_{2cc}$.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.6
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• pp.309-315
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• 2006

Purpose: Accurate evaluation of cervical lymph node (LN) metastasis of head and neck squamous cell canter (SCC) is important to treatment planning. We evaluated the diagnostic accuracy of F-18 fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for the detection of cervical LN metastasis of head and neck SCC and performed a retrospective comparison with CT/MRI findings. Materials & Methods: Seventeen patients with pathologically proven head and neck SCC underwent F-18 FDG PET/CT and CT/MRI within 4 week before surgery. We recorded lymph node metastases according to the neck level system of imaging-based nodal classification. F-18 FDG PET/CT images were analyzed visually for assessment of regional tracer uptake in LN. We analyzed the differences in sensitivity and specificity between F-18 FDG PET/CT and CT/MRI using the Chi-square test. Results: Among the 17 patients, a total of 123 LN levels were dissected, 29 of which showed metastatic involvement. The sensitivity and specificity of F-18 FDG PET/CT for detecting cervical LN metastasis on a level-by-level basis were 69% (20/29) and 99% (93/94). The sensitivity and specificity of CT/MRI were 62% (18/29) and 96% (90/94). There was no significant difference in diagnostic accuracy between F-18 FDG PET/CT and CT/MRI. Interestingly, F-18 FDG PET/CT detected double primary tumor (hepatocellular carcinoma) and rib metastasis, respectively. Conclusion: There was not statistically significant difference of diagnostic accuracy between F-18 FDG PET/CT and CT/MRI for the detection of cervical LN metastasis of head and neck SCC. The low sensitivity of F-18 FDG PET/CT was due to limited resolution for small metastatic deposits.