Sun Jong Kim

Utility of Intravoxel Incoherent Motion MR Imaging for Distinguishing Recurrent Metastatic Tumor from Treatment Effect following Gamma Knife Radiosurgery: Initial Experience

BACKGROUND AND PURPOSE: Intravoxel incoherent motion MR imaging can simultaneously measure the diffusion and perfusion characteristics of brain tumors. Our aim was to determine the utility of intravoxel incoherent motion–derived perfusion and diffusion parameters for assessing the treatment response of metastatic brain tumor following gamma knife radiosurgery. MATERIALS AND METHODS: Ninety-one consecutive patients with metastatic brain tumor treated with gamma knife radiosurgery were assessed by using intravoxel incoherent motion imaging. Two readers independently calculated the 90th percentile and the 10th percentile histogram cutoffs for perfusion, normalized CBV, diffusion, and ADC. Areas under the receiver operating characteristic curve and interreader agreement were assessed. RESULTS: With the combination of the 90th percentile histogram cutoff for perfusion and the 10th percentile histogram cutoff for diffusion, the sensitivity and specificity for differentiating recurrent tumor and treatment were 79.5% and 92.3% for reader 1 and 84.6% and 94.2% for reader 2, respectively. With the combination of the 90th percentile histogram cutoff for normalized CBV and the 10th percentile histogram cutoff for ADC, the sensitivity and specificity for differentiating recurrent tumor and treatment were 69.2% and 100.0% for reader 1 and 74.3% and 100.0% for reader 2, respectively. Compared with the combination of 90th percentile histogram cutoff for normalized CBV and the 10th percentile histogram cutoff for ADC, adding intravoxel incoherent motion to 90th percentile histogram cutoff for normalized CBV substantially improved the diagnostic accuracy for differentiating recurrent tumor and treatment from 86.8% to 92.3% for reader 1 and from 89.0% to 93.4% for reader 2, respectively. The intraclass correlation coefficients between readers were higher for perfusion parameters (intraclass correlation coefficient range, 0.84–0.89) than for diffusion parameters (intraclass correlation coefficient range, 0.68–0.79). CONCLUSIONS: Following gamma knife radiosurgery, intravoxel incoherent motion MR imaging can be used as a noninvasive imaging biomarker for differentiating recurrent tumor from treatment effect in patients with metastatic brain tumor.

Epidemiological analysis of critically ill adult patients with pandemic influenza A(H1N1) in South Korea

A total of 245 patients with confirmed 2009 H1N1 influenza were admitted to the intensive-care units of 28 hospitals (South Korea). Their mean age was 55.3 years with 68.6% aged >50 years, and 54.7% male. Nine were obese and three were pregnant. One or more comorbidities were present in 83.7%, and nosocomial acquisition occurred in 14.3%. In total, 107 (43.7%) patients received corticosteroids and 66.1% required mechanical ventilation. Eighty (32.7%) patients died within 30 days after onset of symptoms and 99 (40.4%) within 90 days. Multivariate logistic regression analysis showed that the clinicians decision to prescribe corticosteroids, older age, Sequential Organ Failure Assessment score and nosocomial bacterial pneumonia were independent risk factors for 90-day mortality. In contrast with Western countries, critical illness in Korea in relation to 2009 H1N1 was most common in older patients with chronic comorbidities; nosocomial acquisition occurred occasionally but disease in obese or pregnant patients was uncommon.

Prevention of Venous Thromboembolism in Medical Intensive Care Unit: A Multicenter Observational Study in Korea

Patients admitted to medical intensive care unit (MICU) are at increased risk for venous thromboembolism (VTE); and prophylaxis is recommended. However, the actual range and frequency of VTE prophylaxis administered to MICU patients are not well defined. Patients over 40 yr of age and expected MICU stay of more than 48 hr were eligible for this observational cohort study of 23 MICUs in Korea. Patients already on anticoagulation therapy or those requiring anticoagulation for reasons other than VTE were excluded. Among 830 patients, VTE prophylaxis was given to 560 (67.5%) patients. Among 560 patients, 323 (38.9%) received pharmacoprophylaxis, 318 (38.4%) received mechanical prophylaxis and 81 (9.8%) received both forms of prophylaxis. About 74% of patients in the pharmacoprophylaxis group received low molecular weight heparin and 53% of the patients in the mechanical prophylaxis group used intermittent pneumatic compression. Most of the patients (90%) had more than one risk factor for VTE and the most common risk factor was old age, followed by heart and respiratory failure. In this observational cohort study of 23 MICUs in Korea, 67.5% of patients received thromboprophylaxis. Further studies are needed to clarify the role and efficacy of VTE prophylaxis in Korean critically ill patients.

Ethical issues recognized by critical care nurses in the intensive care units of a tertiary hospital during two separate periods.

This research aimed to investigate the changes in ethical issues in everyday clinical practice recognized by critical care nurses during two observation periods. We conducted a retrospective analysis of data obtained by prospective questionnaire surveys of nurses in the intensive care units (ICU) of a tertiary university-affiliated hospital in Seoul, Korea. Data were collected prospectively during two different periods, February 2002-January 2003 (Period 1) and August 2011-July 2012 (Period 2). Significantly fewer cases with ethical issues were reported in Period 2 than in Period 1 (89 cases [2.1%] of 4,291 ICU admissions vs. 51 [0.5%] of 9,302 ICU admissions, respectively; P < 0.001). The highest incidence of cases with identified ethical issues in both Periods occurred in MICU. The major source of ethical issues in Periods 1 and 2 was behavior-related. Among behaviorrelated issues, inappropriate healthcare professional behavior was predominant in both periods and mainly involved resident physicians. Ethical issue numbers regarding end-oflife (EOL) care significantly decreased in the proportion with respect to ethical issues during Period 2 (P = 0.044). In conclusion, the decreased incidence of cases with identified ethical issues in Period 2 might be associated with ethical enhancement related with EOL and improvements in the ICU care environment of the studied hospital. However, behaviorrelated issues involving resident physicians represent a considerable proportion of ethical issues encountered by critical care nurses. A systemic approach to solve behavior-related issues of resident physicians seems to be required to enhance an ethical environment in the studied ICU. Graphical Abstract

Clinically Relevant Imaging Features for MGMT Promoter Methylation in Multiple Glioblastoma Studies: A Systematic Review and Meta-Analysis

BACKGROUND: O6-methylguanine methyltransferase (MGMT) promoter methylation status has been reported as a prognostic biomarker in clinical trials. PURPOSE: Our aim was to systematically evaluate imaging features of MGMT promoter methylated glioblastoma and to determine the diagnostic performance of MR imaging for prediction of MGMT promoter methylation in patients with newly diagnosed glioblastoma. DATA SOURCES: A computerized search of Ovid MEDLINE and EMBASE up to February 27, 2018, was conducted. STUDY SELECTION: We selected studies evaluating imaging features of MGMT promoter methylated glioblastoma and the diagnostic performance of MR imaging for prediction of MGMT promoter methylation. DATA ANALYSIS: Pooled estimates of sensitivity and specificity were calculated using a hierarchic logistic regression model. Meta-regression and sensitivity analysis were performed. DATA SYNTHESIS: Twenty-two articles including 2199 patients were included. MGMT promoter methylated glioblastoma is likely to show less edema, high ADC, and low perfusion. Ten articles including 753 patients were included in the meta-analysis. The summary sensitivity was 79% (95% CI, 72%–85%), and the summary specificity was 78% (95% CI, 71%–84%). In the meta-regression, MGMT promoter methylation and mean age were associated with heterogeneity. Sensitivity analysis excluding 1 study resolved the heterogeneity. LIMITATIONS: Included studies used a variety of different MR imaging techniques to predict MGMT promoter methylation. CONCLUSIONS: MGMT promotor methylated glioblastoma is likely to show less aggressive imaging features than MGMT promotor unmethylated glioblastoma. Despite the variety of different MR imaging techniques used, MR imaging in patients with newly diagnosed glioblastoma was shown to have the potential to predict MGMT promoter methylation noninvasively.

MRI Findings in Tumefactive Demyelinating Lesions: A Systematic Review and Meta-Analysis

BACKGROUND: Accurate diagnosis of tumefactive demyelinating lesions is clinically important to avoid unnecessary invasive biopsy or inappropriate treatment. PURPOSE: We aimed to evaluate conventional and advanced MR imaging findings of tumefactive demyelinating lesions and determine the diagnostic performance of MR imaging for differentiating tumefactive demyelinating lesions from primary brain tumor. DATA SOURCES: A systematic search of Ovid MEDLINE and EMBASE up to December 6, 2017, was conducted. STUDY SELECTION: Original articles describing MR imaging findings in patients with tumefactive demyelinating lesions were selected. DATA ANALYSIS: The pooled incidences of conventional MR imaging findings of tumefactive demyelinating lesions were obtained with the DerSimonian and Liard random-effects model. The pooled sensitivity and specificity of MR imaging for differentiating tumefactive demyelinating lesions from primary brain tumor were obtained using the bivariate random-effects model. DATA SYNTHESIS: Nineteen eligible studies with 476 patients with tumefactive demyelinating lesions were included. The pooled incidence of open ring or incomplete rim enhancement was 35% (95% CI, 24%–47%), which was significantly higher than the incidence of closed ring or complete rim enhancement (18% [95% CI, 11%–29%]; P = .0281). The pooled incidences of T2 hypointense rim, absent or mild mass effect, and absent or mild perilesional edema were 48%, 67%, and 57%, respectively. On advanced MR imaging, tumefactive demyelinating lesions showed a high apparent diffusion coefficient, peripheral restricted diffusion, and low cerebral blood volume. The pooled sensitivity and specificity of MR imaging for differentiating tumefactive demyelinating lesions from primary brain tumor were 89% (95% CI, 82%–93%) and 94% (95% CI, 89%–97%), respectively. LIMITATIONS: Seventeen of 19 studies were retrospective studies. CONCLUSIONS: Conventional MR imaging findings may help differentiate tumefactive demyelinating lesions from primary brain tumor, though further study is needed to determine the added value of advanced MR imaging.

Diffusion-Weighted Imaging and Diffusion Tensor Imaging for Differentiating High-Grade Glioma from Solitary Brain Metastasis: A Systematic Review and Meta-Analysis

BACKGROUND: Accurate diagnosis of high-grade glioma and solitary brain metastasis is clinically important because it affects the patients outcome and alters patient management. PURPOSE: To evaluate the diagnostic performance of DWI and DTI for differentiating high-grade glioma from solitary brain metastasis. DATA SOURCES: A literature search of Ovid MEDLINE and EMBASE was conducted up to November 10, 2017. STUDY SELECTION: Studies evaluating the diagnostic performance of DWI and DTI for differentiating high-grade glioma from solitary brain metastasis were selected. DATA ANALYSIS: Summary sensitivity and specificity were established by hierarchic logistic regression modeling. Multiple subgroup analyses were also performed. DATA SYNTHESIS: Fourteen studies with 1143 patients were included. The individual sensitivities and specificities of the 14 included studies showed a wide variation, ranging from 46.2% to 96.0% for sensitivity and 40.0% to 100.0% for specificity. The pooled sensitivity of both DWI and DTI was 79.8% (95% CI, 70.9%–86.4%), and the pooled specificity was 80.9% (95% CI, 75.1%–85.5%). The area under the hierarchical summary receiver operating characteristic curve was 0.87 (95% CI, 0.84–0.89). The multiple subgroup analyses also demonstrated similar diagnostic performances (sensitivities of 76.8%–84.7% and specificities of 79.7%–84.0%). There was some level of heterogeneity across the included studies (I2 = 36%); however, it did not reach a level of concern. LIMITATIONS: The included studies used various DWI and DTI parameters. CONCLUSIONS: DWI and DTI demonstrated a moderate diagnostic performance for differentiation of high-grade glioma from solitary brain metastasis.

Difference in the recovery of pulmonary function between pulmonary and extrapulmonary acute respiratory distress syndrome

We investigated long-term outcomes in patients with pulmonary and extrapulmonary ARDS including all items of PFT, gas exchange, quality of life, and HRCT, which had not been dealt comprehensively in previous studies. We found that, although most abnormalities on PFT were mild, 62.9% and 51.8% of the patients showed abnormality in PFT and exercise PFT, respectively after more than six months of ARDS onset. Multivariate analysis demonstrated that only significant factor to affect the extent of lesions on HRCT and TLC was the subtype of ARDS. These results suggest that patients with ARDSp would remain more severe lung sequelae after recovery than the ARDSexp patients.