Performance of Prediction Models for Diagnosing Severe Aortic Stenosis Based on Aortic Valve Calcium on Cardiac Computed Tomography: Incorporation of Radiomics and Machine Learning

Objective@#We aimed to develop a prediction model for diagnosing severe aortic stenosis (AS) using computed tomography (CT) radiomics features of aortic valve calcium (AVC) and machine learning (ML) algorithms. @*Materials and Methods@#We retrospectively enrolled 408 patients who underwent cardiac CT between March 2010 and August 2017 and had echocardiographic examinations (240 patients with severe AS on echocardiography [the severe AS group] and 168 patients without severe AS [the non-severe AS group]). Data were divided into a training set (312 patients) and a validation set (96 patients). Using non-contrast-enhanced cardiac CT scans, AVC was segmented, and 128 radiomics features for AVC were extracted. After feature selection was performed with three ML algorithms (least absolute shrinkage and selection operator [LASSO], random forests [RFs], and eXtreme Gradient Boosting [XGBoost]), model classifiers for diagnosing severe AS on echocardiography were developed in combination with three different model classifier methods (logistic regression, RF, and XGBoost). The performance (c-index) of each radiomics prediction model was compared with predictions based on AVC volume and score. @*Results@#The radiomics scores derived from LASSO were significantly different between the severe AS and non-severe AS groups in the validation set (median, 1.563 vs. 0.197, respectively, p 0.05 for all). @*Conclusion@#Models based on the radiomics features of AVC and ML algorithms may perform well for diagnosing severe AS, but the added value compared to AVC volume and score should be investigated further.

Comparative Study on Function and Stability of Sunscreening Products / 대한피부과학회지

BACKGROUND: A lot of protective tools such as sunshades (sun-cap), sun-shielding tints and various sunscreens are widely used to protect solar ultraviolet (UV) radiation. Although dermatologists are aware of these products, they do not know the exact protective efficacy or their stability after strong UV irradiation. OBJECTIVE: We tried to measure the spectal absorbance and transmittance of various sunscreening products. In addition, we measured change of sunscreens's absorbance or transmittance after strong UV irradiation for 30, 60 and 90 minutes. METHODS: We purchased five commercially available sunshades (product A-E), five sun-tinting films (product A-E), and eight sunsceens (product A-H) with similar sun-protection factor (SPF) around 30, and measured spectral absorbance and transmittance of those agents. For the sunscreens, they were irradiated with 250 watt Xenon-Arc lamp and change of spectral responses were evaluated. RESULTS: In absorption and transmission spectra of five different sun-caps, sun-cap C showed very good protection in entire UV range whereas all others protected UV only partially. Absorption and transmission spectra of six different sun-shielding tints showed all of them protected UV fairly well and tint C showed the best protection. Eight different sunscreens showed profound differences in spectal absorbances or transmittances. Sunscreen-A showed the best protection and there was no relationship between price and spectral-protection of sunscreens. In the photo-stability of eight sunscreens after UV-irradiation, there were big differences. Only sunscreen-A showed the least change after UV irradiation, and all other sunscreens showed a change of specta by increased UV-irradiation time. CONCLUSION: Protection efficacies of sunscreening products were variable, and most sunscreens were unstable to strong UV irradiation. Further studies would be necessary to give proper information for protecting UV effectively to dermatologists and consumers.

Effects of the Photostability of Sunscreens on the in vivo Photoprotection / 대한피부과학회지

BACKGROUND: Solar ultraviolet (UV) radiation induces sunburn, immune suppression, and various pigmentary disorders. Sunscreens are widely used to protect those untoward effects by UV but there are reports of phototoxicity or stability problems of sunscreens after exposure to UV. OBJECTIVE: We tried to compare sunscreens with different photostability in terms of their protection against various biologic responses like sunburn, immune suppression or pigmentation. METHODS: Three different sunscreens with SPF around 30 were used; Sunscreen-A (Sc-A) was photochemically inert, sunscreen-B (Sc-B) showed intermediate level of photostability, and sunscreen-C (Sc-C) was the least stable. To observe their in vivo effects, we measured sunscreen-protection against sunburn by back-skin swelling and sunburn cell formation, against immune suppression measured by depletion of Langerhans cells, local and systemic suppression of contact hypersensitivity (CHS), and against pigmentation by irradiation with mixed light source with UVA and UVB lamps that mimic solar UV spectrum. RESULTS: Back skin swellings by 5 kJ/m2 of UVB were protected well by sunscreens, but protection of Sc-C against 50 kJ/m2 of UVB was worse than Sc-A or Sc-B. Sunburn cells were increased significantly in mice irradiated with 5 kJ/m2 of UVB and it was protected by sunscreens, and the effect of photostability was minimal. Depletion of epidermal Langerhans cells by 5 kJ/m2 of UVB was protected completely by sunscreens. Local suppression of CHS by 5 kJ/m2 of UVB was protected by sunscreens, and Sc-A had better protection. But, in the experiment with 50 kJ/m2 of UVB, the protective efficacy was reversed; Sc-A showed worse protection. Systemic suppression of CHS by 10 kJ/m2 of UVB was protected well by sunscreens, and Sc-A had better protection and Sc-C had worse protection. In the experiment irradiated with 100 kJ/m2 of UVB, the protection of sunscreens was decreased, and Sc-B showed better protection, whereas Sc-C showed worse protection. In UV-induced pigmentation, all three sunscreens showed significant protection both by L* value and individual topographic angle (ITA) with the best protection by Sc-A and the worst protection by Sc-B. CONCLUSION: These data showed sunscreens can protect various in vivo responses and photostability of sunscreens played important roles particularly in the back-skin swelling and systemic suppression of CHS by high dose of UVB.

Gianotti-Crosti Syndrome Following Japanese Encephalitis Vaccination

We report a three-year-old Korean boy who presented with itching symmetrical erythematous macules and papules on his face, trunk, and extremities for 1 week. Lymphadenopathies were detected on physical examination. He was vaccinated against Japanese B Encephalitis (JE) 1 day before developing skin rashes. The patient's serum JE antibody titer by hemagglutinin inhibition (HI) test was 1:40. Under the diagnosis of Gianotti-Crosti syndrome following JE vaccination, he was conservatively treated with an antihistamine agent, and his symptoms were all cleared 2 weeks after treatment.

A Case of Chromomycosis Showing Ulcerative Lesions on Dorsa of Hands / 대한피부과학회지

Chromomycosis is a chronic mycosis of the skin and subcutaneous tissue characterized by a brown, thick-walled, round, nonbudding form of causative fungi in the tissue. We report a case of chromomycosis caused by Fonsecaea pedrosoi in a 56-year-old Korean woman who showed 3 x 4cm sized deep ulcerations on the dorsa of both hands. Histopathologically, chronic granulomatous inflammation and sclerotic cells were observed. Fonsecaea pedrosoi was grown into typical black colonies in fungus culture. She was treated with pedicle flap graft followed by oral itraconazole, and showed clinical improvement.

A Case of Painful Piezogenic Pedal Papules / 대한피부과학회지

Piezogenic pedal papules are small, occasionally painful, fat herniation, which become apparent when weight is placed on the heel. We present a case of painful piezogenic pedal papules occurring on both heels of 30-year-old female patient without family history. Clinical and histopathological features confirmed diagnosis. Foot-ankle stocking was effective therapy for painful piezogenic pedal papules.

Coronary Angiographic Findings and Treatment of Coronary Artery Disease in ESRD Patients / 대한신장학회잡지

No abstract available.