A proposal of spirometry reference equations for Korean workers.

Background: Although spirometry results can be interpreted differently depending on the reference equation used, there are no established criteria for selecting reference equations as part of the special health examinations for Korean workers. Thus, it is essential to examine the current use of reference equations in Korea, quantify their impact on result interpretation, and propose reference equations suitable for Korean workers, while also considering the environmental conditions of special health examination facilities. Methods: The 213,640 results from the special health examination database were analyzed to identify changes in the ratio of measured values to reference values of lung capacity in Korean workers with changes in age or height, and changes in the agreement of interpretations with the reference equation used. Data from 238 organizations that participated in the 2018-2019 quality control assessment by the Korea Occupational Safety and Health Agency were used to identify the spirometer model and reference equations used in each special health examination facility. Results: Korean special health examination facilities used six reference equations, and the rate of normal or abnormal ventilatory diagnoses varied with the reference equation used. The prediction curve of the Global Lung Function Initiative 2012-Northeast Asian (GLI2012) equation most resembled that of the normal group, but the spirometry model most commonly used by examination facilities was not compliant with the GLI2012 equation. With a scaling factor of 0.95 applied to the Dr. Choi equation, the agreement with the GLI2012 equation was > 0.81 for men and women. Conclusions: We propose the GLI2012 equation as reference equation for spirometry in Korean workers. The GLI2012 equation exhibited the most suitable prediction curve against the normal lung function group. For devices that cannot use the GLI2012 equation, we recommend applying a scaling factor of 0.95 to the Dr. Choi equation.

Current Role of Computed Tomography in the Evaluation of Acute Coronary Syndrome.

This review article provides an overview regarding the role of computed tomography (CT) in the evaluation of acute chest pain (ACP) in the emergency department (ED), focusing on characteristic CT findings.

High prevalence of a linear valve-like structure on CT at the pulmonary artery terminus of patent ductus arteriosus in adult patients, mimicking endarteritis.

PURPOSE: A linear valve-like structure at the pulmonary artery terminus is identified on CT in some patients with patent ductus arteriosus (PDA) and can potentially be mistaken for endarteritis. The purpose of this study was to evaluate the differences in CT features between adult patients with PDA and a linear structure and those without. MATERIALS AND METHODS: We retrospectively evaluated ECG-gated cardiac CT of 38 patients with PDA dividing them into two groups [patients with linear symmetrical valve-like structure (group1, n = 16), and those without (group 2, n = 22)]. We analyzed CT findings of the PDA including length, minimal and maximal diameter, presence of calcification, and PDA type, comparing the two subgroups. The authors also investigated the prevalence of endarteritis. RESULTS: There was no difference in CT findings between the two groups in the prevalence of calcification and length, and minimal and maximal diameter of PDA. Notably the linear valve-like structure was only identified in type 1 PDA (cone-shaped PDA) (p = 0.04), while there were variable types of PDA in group 2. There was only one case of endarteritis as a complication of PDA in group 1. In contrast to a linear valve-like structure, asymmetrical nodular thickening was noted in the patient with endarteritis on CT overlying the pre-existing linear valve-like structure at the pulmonary end of PDA. CONCLUSION: A linear valve-like structure is frequently identified at the pulmonary end in type 1 PDA. This CT finding should not be mistaken for endarteritis in the absence of other clinical evidence.

Phlegmonous Appearance in the Ipsilateral Paracardiac Fat without Paracardiac Lymph Node Enlargement on Chest CT Favors the Diagnosis of Pleural Tuberculosis over Malignant Pleural Effusion.

This study investigated the potential role of paracardiac fat stranding (FS) interspersed with multiple fluid collections (FC) as a clue to differentiate between pleural tuberculosis (pleural TB) and malignant pleural effusion (MPE). The authors retrospectively analyzed chest computed tomography (CT) findings of 428 patients, 351 with pleural TB and 77 with MPE, focusing on the paracardiac fat, and level of pleural adenosine deaminase (ADA) and blood C-reactive protein (CRP). Two radiologists independently evaluated the chest CT findings regarding the paracardiac fat pad ipsilateral to the effusion, including FS, FC, phlegmonous appearance (a combination of the FS and multiple FC), and the presence of lymph node enlargement (>1 cm in short axis diameter). There were significant differences between patients with pleural TB and those with MPE with respect to the prevalence of phlegmonous appearance in the ipsilateral paracardiac fat (47.6% and 10.4%, p < 0.001, OR = 7.8; 95% CI 3.7-16.8) and paracardiac lymph node enlargement (1.4% and 19.5%, p < 0.001, OR = 0.06; 95% CI 0.02-0.2) on CT. In contrast, there was no difference in the prevalence of isolated FS or multiple FC within the ipsilateral paracardiac fat between the two groups. Median pleural ADA and serum CRP level were higher in patients with pleural TB accompanied by phlegmonous appearance in paracardiac fat compared to those without that appearance (ADA: median 104 IU/L versus 90 IU/L, p < 0.001; CRP: 6.5 mg/dL versus 4.2 mg/dL, p < 0.001). In conclusion, phlegmonous appearance in the ipsilateral paracardiac fat without paracardiac lymph node enlargement on chest CT favors a diagnosis of pleural TB over MPE.

Analysis of Endoplasmic Reticulum (ER) Stress Induced during Somatic Cell Nuclear Transfer (SCNT) Process in Porcine SCNT Embryos.

This study investigates the endoplasmic reticulum (ER) stress and subsequent apoptosis in duced during somatic cell nuclear transfer (SCNT) process of porcine SCNT embryos. Porcine SCNT and in vitro fertilization (IVF) embryos were sampled at 3 h and 20 h after SCNT or IVF and at the blastocyst stage for mRNA extraction. The x-box binding protein 1 (Xbp1) mRNA and the expressions of ER stress-associated genes were confirmed by RT-PCR or RT-qPCR. Apoptotic gene expression was analyzed by RT-PCR. Before commencing SCNT, somatic cells treated with tunicamycin (TM), an ER stress inducer, confirmed the splicing of Xbp1 mRNA and increased expressions of ER stress-associated genes. In all the embryonic stages, the SCNT embryos, when compared with the IVF embryos, showed slightly increased expression of spliced Xbp1 (Xbp1s) mRNA and significantly increased expression of ER stress-associated genes (p<0.05). In all stages, apoptotic gene expression was slightly higher in the SCNT embryos, but not significantly different from that of the IVF embryos except for the Bax/Bcl2L1 ratio in the 1-cell stage (p<0.05). The result of this study indicates that excessive ER stress can be induced by the SCNT process, which induce apoptosis of SCNT embryos.

Differences in the CT findings between vulnerable plaque and culprit lesions in acute coronary syndrome.

BACKGROUND: The CT finding of "vulnerable plaque" is widely regarded as similar to that of a culprit lesion in an acute coronary syndrome (ACS). However, this hypothesis may not be accurate, since "vulnerable plaques" may substantially change their morphology when they rupture to cause an ACS. METHODS: We retrospectively evaluated coronary CT angiography data sets of 25 patients with ACS who had vulnerable (n = 10) or culprit plaques (n = 15). We analyzed CT features including positive remodeling (PR), low attenuation plaque (LAP), the napkin ring sign (NRS), degree of stenosis (normal, <50%, 50-99%, 100%), and myocardial hypoperfusion in the left ventricle. RESULTS: There was no difference in the prevalence of PR, NRS, or LAP between vulnerable and culprit plaques. In contrast, a majority (80%, 8/10) of vulnerable plaques were associated with <50% luminal stenosis while total occlusion was identified in 47% (7/15) of culprit plaques (p = .037). In all patients with occlusion, myocardial hypoperfusion was demonstrated in the corresponding arterial territory on CT. CONCLUSION: CT features of vulnerable and culprit plaques differ in cases with thrombotic occlusion reflecting dynamic plaque changes related to the episode of ACS.

Diagnosis of Grave's disease with pulmonary hypertension on chest CT.

OBJECTIVE: To evaluate the diagnostic accuracy of chest CT findings to diagnose Grave's disease in pulmonary hypertension. METHODS: We retrospectively evaluated chest CT and the medical records of 13 patients with Grave's disease with (n=6) or without pulmonary hypertension (n=7) and in 17 control patients. RESULTS: Presence of iso-attenuation of diffusely enlarged thyroid glands compared with adjacent neck muscle on non-enhanced CT as a diagnostic clue of Grave's disease, and assessment of pulmonary hypertension on CT has high diagnostic accuracy. CONCLUSION: Chest CT has the potential to diagnose Grave's disease with pulmonary hypertension in the absence of other information.

Axl signaling induces development of natural killer cells in vitro and in vivo.

Natural killer (NK) cells have been well known to play a critical role in innate immunity, but they are also capable of regulating adaptive immunity through the induction of T cell-mediated memory response and B cell-mediated autoimmune response. NK cells are differentiated from hematopoietic stem cells (HSCs) in the bone marrow (BM), and a series of surface molecules are expressed on NK cells in a differentiation stage-specific manner. Axl receptor tyrosine kinase is originally identified as homeostatic regulators for antigen-presenting cells, and its ligand, growth-arrest-specific gene 6 (Gas6), has been reported to promote cell survival, proliferation, and migration, but their regulatory role in the development and effector function of NK cells is not yet fully understood. In this study, to investigate whether Axl is required for the regulation of NK cell development, the expression of mature NK (mNK) cell-specific receptors and NK cell-associated genes was analyzed in the differentiated HSCs-derived NK cells in vitro and the NK cells harvested from Axl-/- mice. We found that agonistic anti-Axl antibody or recombinant Gas6 specifically upregulated the expression of mNK cell-specific receptors, such as LY49A, Ly49G2, Ly49C/F/I, NKG2A/C/E (1.5- to 3.5-fold increase), and NK cell-associated genes, such as IL-2Rß (2.3- or 2.4-fold increase), Perforin (4.1- or 2.1-fold increase), IL-15Rα (2.14- or 2.04-fold increase), and IFN-γ (3.3- or 2.8-fold increase) compared to each isotype control, whereas it was abrogated by treatment of Axl-Ig. Anti-Axl antibody or rGas6 also induced a 2.5- or 1.9-fold increase in the proliferation of developing NK cells compared to each control, respectively. mNK cell populations expressing mNK cell-specific receptors were reduced about twofold in NK cells differentiated from HSCs of Axl-/- mice compared with those of wild-type mice. Furthermore, the triggering of Axl signaling by agonistic anti-Axl antibody promoted the cytolytic activity (1.5- to 1.9-fold increase) against target tumor cells. In B16F10 melanoma-bearing mice, the number of metastatic colonies was decreased by 83 % by the administration of mNK cells treated with anti-Axl antibody compared to control Ig. These data suggest that Axl plays an essential role in the regulation of NK cell development as well as NK effector function.

Computed Tomography Diagnosis of Nonspecific Acute Chest Pain in the Emergency Department: From Typical Acute Coronary Syndrome to Various Unusual Mimics.

It is a challenging task for emergency department physicians to establish a precise and rapid diagnosis based only on clinical and laboratory findings in patients who present with nonspecific acute chest pain. In this circumstance, CT angiography can provide important clues to the diagnosis. To provide a rapid diagnosis of acute coronary syndrome (ACS) and its various mimics, the physician should enumerate each possible cause of acute chest pain on the basis of an objective assessment of pretest probability. On the basis of clinical suspicion, the appropriate CT protocol should then be performed. Moreover, radiologists should be familiar with typical CT findings of ACS and its various mimics to assist the emergency department physician in diagnosing patients with nonspecific acute chest pain. This review article presents an overview on choosing an appropriate CT protocol in patients with nonspecific acute chest pain and provides specific CT findings of ACS and various mimics of ACS.

Presence of subpleural pulmonary interstitial emphysema as an indication of single or multiple alveolar ruptures on CT in patients with spontaneous pneumomediastinum.

Background There are no previous reports regarding the computed tomography (CT) findings of subpleural pulmonary interstitial emphysema (PIE) in patients with spontaneous pneumomediastinum. Purpose To evaluate CT findings of subpleural PIE that may indicate a direct site of terminal alveolar rupture. Material and Methods We retrospectively evaluated chest CT and the medical records of 34 patients with spontaneous pneumomediastinum. Subpleural PIE was defined as the presence of an interstitial air collection in the subpleural portion of the lungs excluding the bronchovascular bundle. Results Subpleural PIE on CT was identified in six of 34 patients (17.6%) with spontaneous pneumomediastinum. In four of these (66.7%), subpleural PIE was present in multiple lobes suggesting multiple simultaneous ruptures of terminal alveoli. The shape of subpleural PIE was elongated linear (4/6), branching and linear (1/6), and elliptical (1/6). Conclusion The presence of subpleural PIE on CT suggests an origin of pneumomediastinal air from alveolar rupture.

A Case of Complete Unroofed Coronary Sinus Syndrome Combined With Coronary Sinus Stenosis Leading to Asymptomatic Presentation.

We describe a patient with an asymptomatic complete unroofed coronary sinus (CS) syndrome associated with the CS stenosis in the absence of a persistent left superior vena cava (SVC) as identified on coronary computed tomography angiography. There was a large defect between the CS and the left atrium (i.e. a large left-to-right shunt), but an unusual combination of the absence of a persistent left SVC (i.e. no risk for brain abscess due to the absence of a right-to-left shunt) and the CS stenosis (i.e. a markedly reduced degree of a left-to-right shunt), resulting in an asymptomatic presentation.

MDCT evaluation of atherosclerotic coronary artery disease: what should radiologists know?

As an important tool for diagnosing acute coronary syndrome and stable angina, coronary CT angiography has been increasingly being performed in patients presenting with atypical chest pain. In order to help treating patients more efficiently, it is crucial for radiologists to have a comprehensive understanding about mechanisms and clinical aspects as well as CT findings of coronary atherosclerosis per se. A thorough understanding and optimal performance of coronary CT angiography may lead to reduction of unjustified downstream testing. This article provides a clinical and radiological overview of coronary atherosclerosis, and a practical guideline about how to interpret degree of stenosis on coronary CT angiography.

Temporary semi-jailing technique for coil embolization of wide-neck aneurysm with small caliber parent artery following incomplete clipping.

The authors describe the use of a self-expandable stent in a temporary deployment for treatment of a very wide-neck A1 segment of anterior cerebral artery (ACA) aneurysm following incomplete clipping. A 39-year-old hypertensive man presenting with seizure-like movement underwent computed tomography, which showed acute subarachnoid hemorrhage and an A1 segment of ACA aneurysm with superior and inferior projection. He underwent surgical clipping of the aneurysm, but superior and posterior portion of wide-neck aneurysm remained. We decided to treat the remnant aneurysm using an endovascular modality. After selection of the aneurysm, coil packing was performed assisted by the temporary semi-jailing technique. The Enterprise stent (Cordis Neurovascular, Miami, FL, USA) was deployed and recaptured repeatedly for angiography to ensure safety of the small caliber parent artery. Successful semi-deployment and recapture of the stent allowed subtotal coil occlusion of the aneurysm with good anatomic and clinical results. No complications were encountered. The stent could be recaptured up to the point where the proximal end of the stent marker was aligned with distal marker band of the microcatheter, approximately 70% of the stent length. The temporary semi-jailing technique is feasible for wide-neck aneurysm with small caliber parent artery.

Carotid Doppler ultrasonography as a surrogate for coronary CT angiography to exclude subclinical coronary atherosclerosis in asymptomatic patients with a negative coronary calcium score.

PURPOSE: To evaluate the diagnostic accuracy of carotid Doppler ultrasonography (CDU) to predict the presence of subclinical coronary atherosclerosis in asymptomatic subjects with a zero coronary calcium score. METHODS: Retrospective study of CDU and coronary CT angiography (CTA) findings in 118 asymptomatic subjects with a zero calcium score. CDU was considered abnormal when carotid intima-media thickness was >75 percentile or was ≥ 1 mm, or in presence of carotid plaque(s). We analyzed the diagnostic accuracy of CDU to predict the presence of non-calcified coronary plaque in comparison with coronary CTA. RESULTS: The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of abnormal CDU to identify the presence of non-calcified coronary plaque on coronary CTA were 82.4% [(14/17); 95% confidence interval (CI), 56.6%-96.2%], 53.5% [(54/101); 95% CI, 43.3%-63.5%], 23.0% [(14/61); 95% CI, 13.1%-35.6%], and 94.7% [(54/57); 95% CI, 85.4%-98.9%], respectively. CONCLUSIONS: Although CDU has a low PPV for identifying the presence of non-calcified plaque on coronary CTA, its NPV is high to exclude subclinical coronary atherosclerosis in asymptomatic subjects with a zero calcium score.

A case of paradoxical air embolism in the coronary artery through a patent foramen ovale demonstrated by coronary CT angiography.

We present a case of paradoxical air embolism (PAE) in the distal right coronary artery identified by coronary CT angiography. The underlying cause of PAE in the distal right coronary artery was a patent foramen ovale because the typical CT findings of a patent foramen ovale (i.e., combination of findings of the presence of a slit-like contrast column in the interatrial septum and a contrast jet through the septum) were identified by coronary CT angiography.

The Ratio of Descending Aortic Enhancement to Main Pulmonary Artery Enhancement Measured on Pulmonary CT Angiography as a Finding to Predict Poor Outcome in Patients with Massive or Submassive Pulmonary Embolism.

BACKGROUND: The purpose of this study was to evaluate whether measuring the ratio of descending aortic enhancement (DAE) to main pulmonary artery enhancement (MPAE) on pulmonary computed tomography angiography (PCTA) can predict poor outcome in patients with acute massive or submassive pulmonary embolism (PE). METHODS: We retrospectively, reviewed computed tomgraphy findings and charts of 37 patients with acute PE and right ventricular dysfunction. We divided the enrolled patients into 3 groups; group Ia (n=8), comprised of patients with major adverse event (MAE); group Ib (n=5), consisted of those with PE-related MAE; and group II (n=29), those without MAE. We analyzed the right ventricular diameter (RVD)/left ventricular diameter (LVD) and DAE/MPAE on PCTA. RESULTS: For observer 1, RVD/LVD in group Ia (1.9±0.36 vs. 1.44±0.38, p=0.009) and group Ib (1.87±0.37 vs. 1.44±0.38, p=0.044) were significantly higher than that of group II. For observer 2, RVD/LVD in group Ia (1.71±0.18 vs. 1.41±0.47, p=0.027) was significantly greater than that of group II, but RVD/LVD of group Ib was not (1.68±0.2 vs. 1.41±0.47, p=0.093). For both observers, there was a significant difference of DAE/MPAE between group Ib and group II (0.32±0.15 vs. 0.64±0.24, p=0.005; 0.34±0.16 vs. 0.64±0.22, p=0.004), but no significant difference of DAE/MPAE between group Ia and group II (0.51±0.3 vs. 0.64±0.24, p=0.268; 0.53±0.29 vs. 0.64±0.22, p=0.302). Intra-class correlation coefficient (ICC) for the measurement of DAE/MPAE (ICC=0.97) was higher than that of RVD/LVD (ICC=0.74). CONCLUSION: DAE/MPAE measured on PCTA may predict PE-related poor outcomes in patients with massive or submassive PE with an excellent inter-observer agreement.

A case of a patient with protein C deficiency presenting with concurrent thromboses in the pulmonary arteries and innominate artery: a suggestive computed tomographic finding of thrombophilia.

The incidence of arterial thrombosis in patients with protein C deficiency is relatively low compared with that of venous thrombosis. To our knowledge, there is no previously published report of a protein C deficiency patient with simultaneous thromboses in the pulmonary artery and innominate artery in the English literature. We present a case of a protein C deficiency in which the presence of concurrent clots in the pulmonary arteries and innominate artery demonstrated on a pulmonary computed tomographic angiography provided an important clue permitting diagnosis of the deficiency.