• Journal of Medicine and Life Science
• /
• v.19 no.2
• /
• pp.57-65
• /
• 2022

This study aimed to compare the Korean Activity Status Index (KASI) with the cardiopulmonary exercise test (CPET) among patients with acute myocardial infarction. A total of 2,268 patients (85.4% male; mean age, 59.3±10.2 years; range, 23-90 years) diagnosed with acute myocardial infarction were enrolled in the Regional Center Myocardial Infarction Registry between July 2016 and June 2019. The KASI is a tool used to measure functional capacity by asking patients about their ability to perform specific activities and then scoring their responses. In contrast, CPET is the gold standard for assessing the objective functional capacity in patients undergoing cardiac rehabilitation. Peak oxygen uptake (VO_2peak) was used to analyze the correlation. Patients who completed two consecutive KASI and CPET evaluations during their first (KASI_1, VO_2peak_1) and second visits (KASI_2, VO_2peak_2) for cardiac rehabilitation were included in the study. The mean KASI_1 and KASI_2 scores were 43.3±14.3 and 49.8±13.9, respectively, and the mean VO_2peak_1 and VO_2peak_2 scores were 25.9±8.0 and 28.5±8.3, respectively. Both the KASI scores were significantly correlated with the measured VO_2peak during each visit, with correlation coefficients of 0.385 (P<0.001) and 0.346 (P<0.001), respectively. Moreover, the KASI score and VO_2peak had a linear relationship (VO_2peak_1=0.22×KASI_1+16.5, P<0.001; VO_2peak_2=0.21×KASI_2+18.2,VO_2peak_2=0.21×KASI_2+18.2, P<0.001). This study revealed that the KASI is a valid measure for the follow-up evaluation of the functional capacity of patients. These findings suggest that VO_2peak can be predicted using the KASI score in patients who do not undergo CPET.

• Korean Journal of Radiology
• /
• v.22 no.3
• /
• pp.344-353
• /
• 2021

Objective: The mitotic count of gastrointestinal stromal tumors (GIST) is closely associated with the risk of planting and metastasis. The purpose of this study was to develop a predictive model for the mitotic index of local primary GIST, based on deep learning algorithm. Materials and Methods: Abdominal contrast-enhanced CT images of 148 pathologically confirmed GIST cases were retrospectively collected for the development of a deep learning classification algorithm. The areas of GIST masses on the CT images were retrospectively labelled by an experienced radiologist. The postoperative pathological mitotic count was considered as the gold standard (high mitotic count, > 5/50 high-power fields [HPFs]; low mitotic count, ≤ 5/50 HPFs). A binary classification model was trained on the basis of the VGG16 convolutional neural network, using the CT images with the training set (n = 108), validation set (n = 20), and the test set (n = 20). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated at both, the image level and the patient level. The receiver operating characteristic curves were generated on the basis of the model prediction results and the area under curves (AUCs) were calculated. The risk categories of the tumors were predicted according to the Armed Forces Institute of Pathology criteria. Results: At the image level, the classification prediction results of the mitotic counts in the test cohort were as follows: sensitivity 85.7% (95% confidence interval [CI]: 0.834-0.877), specificity 67.5% (95% CI: 0.636-0.712), PPV 82.1% (95% CI: 0.797-0.843), NPV 73.0% (95% CI: 0.691-0.766), and AUC 0.771 (95% CI: 0.750-0.791). At the patient level, the classification prediction results in the test cohort were as follows: sensitivity 90.0% (95% CI: 0.541-0.995), specificity 70.0% (95% CI: 0.354-0.919), PPV 75.0% (95% CI: 0.428-0.933), NPV 87.5% (95% CI: 0.467-0.993), and AUC 0.800 (95% CI: 0.563-0.943). Conclusion: We developed and preliminarily verified the GIST mitotic count binary prediction model, based on the VGG convolutional neural network. The model displayed a good predictive performance.

• Korean Circulation Journal
• /
• v.53 no.7
• /
• pp.425-451
• /
• 2023

Most patients with heart failure (HF) have multiple comorbidities, which impact their quality of life, aggravate HF, and increase mortality. Cardiovascular comorbidities include systemic and pulmonary hypertension, ischemic and valvular heart diseases, and atrial fibrillation. Non-cardiovascular comorbidities include diabetes mellitus (DM), chronic kidney and pulmonary diseases, iron deficiency and anemia, and sleep apnea. In patients with HF with hypertension and left ventricular hypertrophy, renin-angiotensin system inhibitors combined with calcium channel blockers and/or diuretics is an effective treatment regimen. Measurement of pulmonary vascular resistance via right heart catheterization is recommended for patients with HF considered suitable for implantation of mechanical circulatory support devices or as heart transplantation candidates. Coronary angiography remains the gold standard for the diagnosis and reperfusion in patients with HF and angina pectoris refractory to antianginal medications. In patients with HF and atrial fibrillation, longterm anticoagulants are recommended according to the CHA₂DS₂-VASc scores. Valvular heart diseases should be treated medically and/or surgically. In patients with HF and DM, metformin is relatively safer; thiazolidinediones cause fluid retention and should be avoided in patients with HF and dyspnea. In renal insufficiency, both volume status and cardiac performance are important for therapy guidance. In patients with HF and pulmonary disease, beta-blockers are underused, which may be related to increased mortality. In patients with HF and anemia, iron supplementation can help improve symptoms. In obstructive sleep apnea, continuous positive airway pressure therapy helps avoid severe nocturnal hypoxia. Appropriate management of comorbidities is important for improving clinical outcomes in patients with HF.

• Korean Journal of Radiology
• /
• v.23 no.1
• /
• pp.77-88
• /
• 2022

Objective: Our study aimed to evaluate the quality of radiomics studies on brain metastases based on the radiomics quality score (RQS), Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) checklist, and the Image Biomarker Standardization Initiative (IBSI) guidelines. Materials and Methods: PubMed MEDLINE, and EMBASE were searched for articles on radiomics for evaluating brain metastases, published until February 2021. Of the 572 articles, 29 relevant original research articles were included and evaluated according to the RQS, TRIPOD checklist, and IBSI guidelines. Results: External validation was performed in only three studies (10.3%). The median RQS was 3.0 (range, -6 to 12), with a low basic adherence rate of 50.0%. The adherence rate was low in comparison to the "gold standard" (10.3%), stating the potential clinical utility (10.3%), performing the cut-off analysis (3.4%), reporting calibration statistics (6.9%), and providing open science and data (3.4%). None of the studies involved test-retest or phantom studies, prospective studies, or cost-effectiveness analyses. The overall rate of adherence to the TRIPOD checklist was 60.3% and low for reporting title (3.4%), blind assessment of outcome (0%), description of the handling of missing data (0%), and presentation of the full prediction model (0%). The majority of studies lacked pre-processing steps, with bias-field correction, isovoxel resampling, skull stripping, and gray-level discretization performed in only six (20.7%), nine (31.0%), four (3.8%), and four (13.8%) studies, respectively. Conclusion: The overall scientific and reporting quality of radiomics studies on brain metastases published during the study period was insufficient. Radiomics studies should adhere to the RQS, TRIPOD, and IBSI guidelines to facilitate the translation of radiomics into the clinical field.

• Korean Journal of Radiology
• /
• v.20 no.1
• /
• pp.114-125
• /
• 2019

Objective: Segmented cardiac cine magnetic resonance imaging (MRI) is the gold standard for cardiac ventricular volumetric assessment. In patients with difficulty in breath-holding or arrhythmia, this technique may generate images with inadequate quality for diagnosis. Real-time cardiac cine MRI has been developed to address this limitation. We aimed to assess the performance of retrospective electrocardiography-gated real-time cine MRI at 3T for left ventricular (LV) volume and mass measurement. Materials and Methods: Fifty-one patients were consecutively enrolled. A series of short-axis cine images covering the entire left ventricle using both segmented and real-time balanced steady-state free precession cardiac cine MRI were obtained. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), and LV mass were measured. The agreement and correlation of the parameters were assessed. Additionally, image quality was evaluated using European CMR Registry (Euro-CMR) score and structure visibility rating. Results: In patients without difficulty in breath-holding or arrhythmia, no significant difference was found in Euro-CMR score between the two techniques (0.3 ± 0.7 vs. 0.3 ± 0.5, p > 0.05). Good agreements and correlations were found between the techniques for measuring EDV, ESV, EF, SV, and LV mass. In patients with difficulty in breath-holding or arrhythmia, segmented cine MRI had a significant higher Euro-CMR score (2.3 ± 1.2 vs. 0.4 ± 0.5, p < 0.001). Conclusion: Real-time cine MRI at 3T allowed the assessment of LV volume with high accuracy and showed a significantly better image quality compared to that of segmented cine MRI in patients with difficulty in breath-holding and arrhythmia.

• Journal of Cardiovascular Imaging
• /
• v.31 no.1
• /
• pp.18-23
• /
• 2023

BACKGROUND: Three-dimensional (3D) transesophageal echocardiogram (TEE) is the gold standard for the diagnosis of degenerative mitral regurgitation (dMR) and preoperative planning for transcatheter mitral valve repair (TMVr). TEE is an invasive modality requiring anesthesia and esophageal intubation. The severe acute respiratory syndrome coronavirus 2 pandemic has limited the number of elective invasive procedures. Multi-detector computed tomographic angiography (MDCT) provides high-resolution images and 3D reconstructions to assess complex mitral anatomy. We hypothesized that MDCT would reveal similar information to TEE relevant to TMVr, thus deferring the need for a preoperative TEE in certain situations like during a pandemic. METHODS: We retrospectively analyzed data on patients who underwent or were evaluated for TMVr for dMR with preoperative MDCT and TEE between 2017 and 2019. Two TEE and 2 MDCT readers, blinded to patient outcome, analyzed: leaflet pathology (flail, degenerative, mixed), leaflet location, mitral valve area (MVA), flail width/gap, anterior-posterior (AP) and commissural diameters, posterior leaflet length, leaflet thickness, presence of mitral valve cleft and degree of mitral annular calcification (MAC). RESULTS: A total of 22 (out of 87) patients had preoperative MDCT. MDCT correctly identified the leaflet pathology in 77% (17/22), flail leaflet in 91% (10/11), MAC degree in 91% (10/11) and the dysfunctional leaflet location in 95% (21/22) of patients. There were no differences in the measurements for MVA, flail width, commissural or AP diameter, posterior leaflet length, and leaflet thickness. MDCT overestimated the measurements of flail gap. CONCLUSIONS: For preoperative TMVr planning, MDCT provided similar measurements to TEE in our study.

• Journal of Trauma and Injury
• /
• v.37 no.1
• /
• pp.37-47
• /
• 2024

Purpose: This study aimed at developing a novel tube thoracostomy technique using the sternum, a fixed anatomical structure, as an indicator to reduce the possibility of incorrect chest tube positioning and complications in patients with chest trauma. Methods: This retrospective study analyzed the data of 184 patients with chest trauma who were aged ≥18 years, visited a single regional trauma center in Korea between April and June 2022, and underwent chest computed tomography (CT) with their arms down. The conventional gold standard, 5th intercostal space (ICS) method, was compared to the lower 1/2, 1/3, and 1/4 of the sternum method by analyzing CT images. Results: When virtual tube thoracostomy routes were drawn at the mid-axillary line at the 5th ICS level, 150 patients (81.5%) on the right side and 179 patients (97.3%) on the left did not pass the diaphragm. However, at the lower 1/2 of the sternum level, 171 patients (92.9%, P<0.001) on the right and 182 patients (98.9%, P= 0.250) on the left did not pass the diaphragm. At the 5th ICS level, 129 patients (70.1%) on the right and 156 patients (84.8%) on the left were located in the safety zone and did not pass the diaphragm. Alternatively, at the lower 1/2, 1/3, and 1/4 of the sternum level, 139 (75.5%, P=0.185), 49 (26.6%, P<0.001), and 10 (5.4%, P<0.001), respectively, on the right, and 146 (79.3%, P=0.041), 69 (37.5%, P<0.001), and 16 (8.7%, P<0.001) on the left were located in the safety zone and did not pass the diaphragm. Compared to the conventional 5th ICS method, the sternum 1/2 method had a safety zone prediction sensitivity of 90.0% to 90.7%, and 97.3% to 100% sensitivity for not passing the diaphragm. Conclusions: Using the sternum length as a tube thoracostomy indicator might be feasible.

• Clinical Endoscopy
• /
• v.57 no.2
• /
• pp.217-225
• /
• 2024

Background/Aims: This study aims to compare polyp detection performance of "Deep-GI," a newly developed artificial intelligence (AI) model, to a previously validated AI model computer-aided polyp detection (CADe) using various false positive (FP) thresholds and determining the best threshold for each model. Methods: Colonoscopy videos were collected prospectively and reviewed by three expert endoscopists (gold standard), trainees, CADe (CAD EYE; Fujifilm Corp.), and Deep-GI. Polyp detection sensitivity (PDS), polyp miss rates (PMR), and false-positive alarm rates (FPR) were compared among the three groups using different FP thresholds for the duration of bounding boxes appearing on the screen. Results: In total, 170 colonoscopy videos were used in this study. Deep-GI showed the highest PDS (99.4% vs. 85.4% vs. 66.7%, p<0.01) and the lowest PMR (0.6% vs. 14.6% vs. 33.3%, p<0.01) when compared to CADe and trainees, respectively. Compared to CADe, Deep-GI demonstrated lower FPR at FP thresholds of ≥0.5 (12.1 vs. 22.4) and ≥1 second (4.4 vs. 6.8) (both p<0.05). However, when the threshold was raised to ≥1.5 seconds, the FPR became comparable (2 vs. 2.4, p=0.3), while the PMR increased from 2% to 10%. Conclusions: Compared to CADe, Deep-GI demonstrated a higher PDS with significantly lower FPR at ≥0.5- and ≥1-second thresholds. At the ≥1.5-second threshold, both systems showed comparable FPR with increased PMR.

• Tuberculosis and Respiratory Diseases
• /
• v.45 no.5
• /
• pp.1000-1011
• /
• 1998

Background: For the diagnosis or evaluation of airway obstruction in bronchial asthma and chronic obstructive lung disorders, various parameters derived from the forced expiratory volume curve and maximal expiratory flow volume curve have been used. Recently the peak expiratory flow(PEF) measured by the peak flow meter is widely used because of its simplicity and convenience. But there were still no data of the predicted normal values measured by the peak flow meter in Korea. This study was to obtain the predicted normal value of PEF and to know the accuracy of this value to predict $FEV_1$. Method: The measurements of PEF by the MiniWright peak flow meter and several parameters derived from the forced expiratory volume and maximal expiratory flow volume curves by the Microspiro HI 501(Chest Co.) were done in 129 men and 125 women without previous history of the respiratory diseases. The predicted normal values of parameters according to the age and the height were obtained, and the regression equation of $FEV_1$ by PEF was calculated. Results: The predicted normal values of PEF(L/min) were -2.45$\times$Age(year) +1.36 $\times$ Height(cm)+427 in men, and -0.96 $\times$ Age (year) + 2.01 $\times$ Height (cm) + 129 in women. FEFmax derived from the maximal expiratory flow volume curve was less than by 125 L/min in men and 118 L/min in women respectively compared to PEF. $FEV_1$(ml) predicted by PEF was 5.98 $\times$ PEF(L/min) + 303 in men, and 4.61 $\times$ PEF(L/min) + 291 in women respectively. Conclusion : The predicted normal value of PEF measured by the peak flow meter was calculated and it could be used as a standard value of PEF while taking care of patients with airway obstruction. $FEV_1$, the gold standard of ventilatory function, could be predicted by PEF to a certain extent.

• Tuberculosis and Respiratory Diseases
• /
• v.51 no.3
• /
• pp.248-259
• /
• 2001

Background : In diagnosis or monitor of the airway obstruction in bronchial asthma, the measurement of $FEV_1$ in the standard method because of its reproducibility and accuracy. But the measurement of peak expiratory flow(PEF) by peak flow meter is much simpler and easier than that of $FEV_1$ especially in children. Yet there have been still no data of the predicted normal values of PEF measured by peak flow meter in Korean children. This study was conducted to provide equations to predict the normal value of PEF and correlation between PEF and $FEV_1$ in healthy children. Method : PEF was measured by MiniWright peak flow meter, and the forced expiratory volume and the maximum expiratory flow volume curves were measured by Microspiro HI 501(Chest Co.) in 346 healthy children(age:5-16 years, 194 boys and 152 girls) without any respiratory symptoms during 2 weeks before the study. The regression equations for various ventilatory parameters according to age and/or height, and the regression equations of $FEV_1$ by PEF were derived. Results : 1. The regression equation for PEF(L/min) was: $12.6{\times}$age(year)+$3.4{\times}$height(cm)-263($R^2=0.85$) in boys, and $6{\times}$age(year)+$3.9{\times}$height(cm)-293($R^2=0.82$) in girls. 2. The value of FEFmax(L/sec) derived from the maximum expiratory flow volume curves was multiplied by 60 to compare with PEF(L/min), and PEF was faster by 125 L/min in boys and 118 L/min in girls, respectively. 3. The regression equation for $FEV_1$(ml) by PEF(L/min) was:$7{\times}$PEF-550($R^2=0.82$) in boys, and $5.8{\times}$PEF-146 ($R^2=0.81$) in girls, respectively. Conclusion : This study provides regression equations predicting the normal values of PEF by age and/or height in children. And the equations for $FEV_1$, a gold standard of ventilatory function, was predicted by PEF. So, in taking care of children with airway obstruction, PEF measured by the peak flow meter can provide useful information.