Purpose: The purpose of this study was to develop dedicated software for quantitative analysis of the airways and to validate the software using airway phantoms and excised swine lung. Materials and Methods: The dedicated software was validated in airway phantoms and excised swine lung through comparison of the actual values with the measurements acquired with dedicated software. The accuracy of the measurements according to the reconstruction methods (standard, lung, sharp) and spatial resolution were compared using airway phantoms. Repeatability of the measurement of airway phantoms was assessed with follow-up CT scans three months later. Results: Airway dimension measurements obtained in airway phantoms and excised swine lung showed good agreements with actual values. Airway measurements were more accurate when the sharp reconstruction algorithm was used and when the spatial resolution was improved using pixels smaller than conventional size. There was good agreement between the initial airway measurements and those obtained three months later. Conclusion: We developed and validated dedicated software for quantitative airway measurement. Reconstruction with sharp algorithms and high spatial resolution images is recommended for obtaining airway measurements.
Purpose: This study aims to describe the clinical characteristics of adrenal insufficiency-associated hypotension in preterm infants and the effects of hydrocortisone therapy on their cardiovascular system and serum electrolytes.Methods: Twelve preterm infants less than 32 gestational weeks admitted to neonatal intensive care unit (NICU) of the Seoul National University Bundang Hospital from January 2007 to August 2009 with clinical and laboratory findings suggestive of adrenal insufficiency were analyzed retrospectively.Results: Gestational age was 27.8±2.5 weeks and birth weight was 1,110±307 g.Postnatal age, postmenstrual age, weight at the onset of adrenal insufficiency-associated hypotension were 19±7 day, 30.6±2.4 weeks, 1,285±365 g.In preterm infants who showed vasopressor resistance, intravenous hydrocortisone was started with a stress dose of 4 mg/kg/day, maintained for 2.2±0.7 days, and then tapered.Serum cortisol concentration before hydrocortisone administration was 11.6±4.1 mg/dL.Mean blood pressure increased from 25.0±5.4mmHg to 35.0±5.3 mmHg, 38.3±8.0 mmHg and 41.9±6.5 mmHg at time of hydrocortisone administration and 2, 4 and 6 hours after hydrocortisone administration.Urine output increased from 0.9±0.6 mL/kg/hr to 4.1±3.4mL/kg/hr.Twelve hours after the administration of hydrocortisone, dopamine requirement decreased from 11.0±2.9µg/kg/min to 8.0±2.3 µg/kg/min, and to 5.5±3.4µg/kg/min after 24 hours.Serum sodium concentration was increased from 130±4 mEq/L to 136±4 mEq/L, serum potassium concentration was decreased from 6.1±1.1 mEq/L to 4.6±0.6 mEq/L before and 12 hours after hydrocortisone administration. Conclusion:In preterm infants with adrenal insufficiency-associated hypotension, hydrocortisone administration improved blood pressure and urine output, decreased vasopressor requirement, and normalized serum electrolyte abnormalities.
Despite previous efforts to build statistical models for predicting the risk of suicidal behavior using machine-learning analysis, a high-accuracy model can lead to overfitting. Furthermore, internal validation cannot completely address this problem. In this study, we created models for predicting the occurrence of suicide attempts among Koreans at high risk of suicide, and we verified these models in an independent cohort. We performed logistic and penalized regression for suicide attempts within 6 months among suicidal ideators and attempters in The Korean Cohort for the Model Predicting a Suicide and Suicide-related Behavior (K-COMPASS). We then validated the models in a test cohort. Our findings indicated that several factors significantly predicted suicide attempts in the models, including young age, suicidal ideation, previous suicidal attempts, anxiety, alcohol abuse, stress, and impulsivity. The area under the curve and positive predictive values were 0.941 and 0.484 after variable selection and 0.751 and 0.084 in the test cohort. The corresponding values for the penalized regression model were 0.943 and 0.524 in the original training cohort and 0.794 and 0.115 in the test cohort. The prediction model constructed through a prospective cohort study of the suicide high-risk group showed satisfactory accuracy even in the test cohort. The accuracy with penalized regression was greater than that with the "classical" logistic model.
<i>Background:</i> Granulocyte colony-stimulating factor (G-CSF) is known to mobilize endothelial progenitor cells (EPCs) from bone marrow. EPCs reportedly promote neovascularization and participate in the repair of lung structure in adult animals. <i>Objective:</i> We tested the hypothesis that G-CSF contributes to alveolar growth by increasing the production of angiogenic growth factor in the lungs of hyperoxia-exposed neonatal mice. <i>Methods:</i> Neonatal mice were exposed to hyperoxia (80%) or room air (RA) for 7 days and treated with G-CSF (50 µg/kg/day) or vehicle for 5 days. Blood was subjected to flow cytometry to gate for CD45<sup>dim/–</sup>/Sca-1<sup>+</sup>/CD133<sup>+</sup>/vascular endothelial growth factor (VEGF) receptor-2 (VEGFR2) to define the EPC population at day 7. <i>Results:</i> The percentage of EPCs in the peripheral blood and VEGF and VEGFR2 levels in the lungs of neonatal mice exposed to hyperoxia were significantly reduced compared to those of mice kept in RA. G-CSF significantly increased EPCs in the peripheral blood, and VEGF and VEGFR2 levels in the lungs of both mice exposed to hyperoxia and mice kept in RA. G-CSF restored alveolarization inhibited by hyperoxia without altering normal alveolarization under RA. <i>Conclusion:</i> G-CSF restored alveolarization inhibited by hyperoxia in the developing lungs and this alveolarization-enhancing effect of G-CSF is associated with mobilization of EPCs and upregulation of VEGF signaling.
The purpose of this study was to explore the effects of CT slice thickness, reconstruction algorithm, and radiation dose on quantification of CT features to characterize lung nodules using a chest phantom. Spherical lung nodule phantoms of known densities (−630 and + 100 HU) were inserted into an anthropomorphic thorax phantom. CT scan was performed ten times with relocations. CT data were reconstructed using 12 different imaging settings; three different slice thicknesses of 1.25, 2.5, and 5.0 mm, two reconstruction kernels of sharp and standard, and two radiation dose of 30 mAs and 12 mAs. Lesions were segmented using a semiautomated method. Twenty representative CT quantitative features representing CT density and texture were compared using multiple regression analysis. In 100 HU nodule phantoms, 18 and 19 among 20 computer features showed significant difference between different mAs and reconstruction algorithms, respectively (p≤0.05). 20, 19, and 19 computer features showed difference between slice thickness of 5.0 vs 1.25, 5.0 vs 2.5, and 2.5 vs 1.25 mm, respectively (p≤0.05). In −630 HU nodule phantoms, 18 and 19 showed significant difference between different mAs and reconstruction algorithms, respectively (p≤0.05). 18, 11, and 17 computer features showed difference between slice thickness of 5.0 vs 1.25, 5.0 vs 2.5, and 2.5 vs 1.25 mm, respectively (p≤0.05). When comparing the absolute value of regression coefficient, the effect of slice thickness in 100 HU nodule and reconstruction algorithm in −630 HU nodule was greater than the effect of remaining scan parameters. The slice thickness, mAs, and reconstruction algorithm had a significant impact on the quantitative image features. In clinical studies involving deep learning or radiomics, it should be noted that differences in values can occur when using computer features obtained from different CT scan parameters in combination. Therefore, when interpreting the statistical analysis results, it is necessary to reflect the difference in the computer features depending on the scan parameters.
Purpose: To compare forward shift of posterior corneal surface and higher-order aberration (HOA) changes after LASIK, LASEK, and wavefront-guided LASEK surgery in moderate myopia Methods: One hundred eighty four eyes undergoing LASIK, LASEK and wavefront-guided LASEK with VISX STAR S4 were included in this study.The posterior corneal elevation was measured with Orbscan before, 2 and 4 months after surgery.Changes of the elevation were assessed using the difference map generated from preoperative and postoperative elevation maps.The values of higher-order aberrations were evaluated preoperatively and 2 months postoperatively with Wavefront aberrometer. Results:The posterior corneal surface displayed forward shift of 27.2±11.45µm, 24.3±9.76µm in LASIK group, 23.4±10.5 µm, 23.6±10.55µm in LASEK group, 24.0±14.95µm, 28.4±14.72 µm in wavefrontguided LASEK group at 2 months and 4 months, respectively.There were no statistically significant differences among those three groups, and between 2 and 4 months.The root mean score (RMS) of HOA was increased after LASIK and LASEK (p=0.000,p=0.000, respectively).The mean change of HOA-RMS was significantly smaller in wavefront-guided LASEK than LASIK or LASEK (p=0.000,p=0.000, respectively, Bonferroni-corrected).Conclusions: The changes of posterior corneal surface forward shift showed no difference among LASIK, LASEK and wavefront-guided LASEK in moderate myopia.HOAs were significantly increased after LASIK and LASEK.The changes of HOAs were significant smaller in wavefront-guided LASEK than LASIK or LASEK.
Purpose : This study aims to describe the clinical characteristics of severe meconium aspiration syndrome (MAS) which re quired mechanical ventilation over 48 h and to delineate the progress of respiratory failure and radiographic findings in severe MAS. Methods : Twelve infants admitted to the Neonatal Intensive Care Unit (NICU) of the Seoul National University Bundang Hospital diagnosed with severe MAS from January 2004 to July 2007 were analyzed retrospectively. Results : The presence of persistent pulmonary hypertension of the newborn (PPHN) is the only independently significant risk factor for a longer hospital stay and longer duration of mechanical ventilation. Surfactant replacement therapy (SRT) was not randomized but only performed in infants with radiographic findings for respiratory distress syndrome (RDS). In the presence of radiographic findings for RDS, the duration of high-frequency oscillatory ventilation was significantly longer. PPHN developed in 8 infants (75%). The PPHN group had a significantly longer duration of mechanical ventilation. All infants who received SRT showed radiographic improvement within 12 h, but there was no significant change in the severity score during the same period. Infants without the PPHN complications showed significant decrease in the severity score within 12 h after SRT, whereas infants with PPHN complications did not. Conclusion : The clinical course of severe MAS differed significantly depending on the development of PPHN. SRT conferred radiographic improvement in infants who showed radiographic findings for RDS, but did not influence the clinical course of MAS significantly. (Korean J Pediatr 2008;51:713-721)
Lee HJ, Kim IO, Kim TK, et al. Dynamic enhancement features of gadophrin-2 on magnetic resonance imaging: An experimental model of vx2 carcinoma and bacterial abscess in rabbit thigh. Invest Radiol 2002;37:663–671. Rationale and Objectives. To determine the dynamic enhancement features of malignant tumor and bacterial abscess in rabbits on magnetic resonance imaging (MRI) after injection of gadolinium mesoporphyrin (gadophrin-2) and to correlate them with histopathologic findings. Methods. Six VX2 carcinomas and six bacterial abscesses were experimentally induced in either thigh of six rabbits. Dynamic T1-weighted MRI was performed before and 1, 3, 5, 10, 30 minutes and 16, 21, 72 hours after intravenous injection of gadophrin-2 (0.05 mmol/kg). The enhancement ratios of lesions were calculated for each time point. All tumors and abscesses were sectioned along the same plane of MR images for a detailed MRI-histopathologic correlation. Results. In tumors and abscesses, peripheral-rim enhancement appeared on MRI at 1, 3, 5, 10, 30 minutes after injection of gadophrin-2. The lesions showed peripheral enhancement with irregular central enhancement or diffuse enhancement after 16 and 21 hours, and there was diffuse enhancement of the entire lesion after 72 hours. Enhancement ratios in tumor-necrosis mixed area and the pure necrotic area in VX2 carcinoma and the central cavity in bacterial abscess were significantly lower than that in the compact cellular portion in VX2 carcinoma and the wall of abscess at early phase (P < 0.01). On delayed phase MRI, there was no statistical significance in enhancement ratio of three histologic parts of VX2 carcinoma (P > 0.05) and two histologic parts of abscess (P > 0.05). Rapid enhancement at early phase with diminishing signal intensity at delayed phase is indicative of viable compact tumor and delayed strong enhancement is indicative of necrosis. Conclusion. It is difficult to distinguish an abscess from a tumor on gadophrin-2 enhanced MRI especially when intratumoral necrosis is prominent. However, the trend and degree of enhancement by gadophrin-2 could be helpful in discrimination between viable tumor and tumor necrosis.
The aim of this study was to analyze changes in the extent of radiographic lesions with treatment in patients with pulmonary tuberculosis (TB) and, further, to identify clinical and radiographic factors related to radiographic response.A prospective cohort study including patients with culture-proven pulmonary TB was performed. The posterior-anterior view films of the chest that had been taken at the time of diagnosis and at 6 months after the initiation of treatment were compared. We expressed the extents of the lesions as percentages involving the parenchyma compared with the remaining normal parenchyma.Among 135 patients enrolled, three failed to achieve smear conversion of sputa after 6 months of treatment. The extent of radiographic lesions decreased from 22.8% at the time of diagnosis to 10.5% after 6 months of treatment. Through the multiple regression model, we found that increasing age (p=0.034), previous history of TB (p=0.016), presence of cavity (p=0.016) or fibrotic lesion (p=0.009), and multidrug-resistant TB (p=0.002) were significantly associated with a poor radiographic response.Patients with less-prominent radiographic improvement and sustained negative tuberculous cultures of the sputa could be closely observed without ordering unnecessary chest radiographs or mycobacterial cultures as well as prolonging treatment.
'%3e%3cg id='b'%3e%3cpath id='a' stroke='%23000' stroke-width='2' d='M-6-25H6m-12 3H6m-12 3H6'/%3e%3cuse xlink:href='%23a' y='44'/%3e%3c/g%3e%3cpath stroke='%23fff' d='M0 17v10'/%3e%3ccircle r='12' fill='%23cd2e3a'/%3e%3cpath fill='%230047a0' d='M0-12A6 6 0 0 0 0 0a6 6 0 0 1 0 12 12 12 0 0 1 0-24z'/%3e%3c/g%3e%3cg transform='rotate(-123.69)'%3e%3cuse xlink:href='%23b'/%3e%3cpath stroke='%23fff' d='M0-23.5v3M0 17v3.5m0 3v3'/%3e%3c/g%3e%3c/svg%3e)
'%3e%3ccircle r='120' fill='%230f47af'/%3e%3cg id='a'%3e%3cpath fill='%23fcdd09' d='m0-96-4.206 12.944 17.348 53.39h-23.13l-2.599 8h74.163l11.011-8H21.553z'/%3e%3cpath stroke='%23fcdd09' stroke-width='4' d='m25.863-35.597 30.564-42.069'/%3e%3c/g%3e%3cuse xlink:href='%23a' transform='rotate(72)'/%3e%3cuse xlink:href='%23a' transform='rotate(144)'/%3e%3cuse xlink:href='%23a' transform='rotate(216)'/%3e%3cuse xlink:href='%23a' transform='rotate(288)'/%3e%3c/g%3e%3c/svg%3e)
