Enhanced dataset synthesis using conditional generative adversarial networks

Ahmet Mert 대한의용생체공학회 2023 Biomedical Engineering Letters (BMEL) Vol.13 No.1

Biomedical data acquisition, and reaching sufficient samples of participants are difficult and time ans effort consuming processes. On the other hand, the success rates of computer aided diagnosis (CAD) algorithms are sample and feature space depended. In this paper, conditional generative adversarial network (CGAN) based enhanced feature generation is proposed to synthesize large sample datasets having higher class separability. Twenty five percent of five medical datasets are used to train CGAN, and the synthetic datasets with any sample size are evaluated and compared to originals. Thus, new datasets can be generated with the help of the CGAN model and lower sample collection. It helps physicians decreasing sample collection processes, and it increases accuracy rates of the CAD systems using generated enhanced data with enhanced feature vectors. The synthesized datasets are classified using nearest neighbor, radial basis function support vector machine and artificial neural network to analyze the effectiveness of the proposed CGAN model.

Revisiting the measurement of keratinized gingiva: a cross-sectional study comparing an intraoral scanner with clinical parameters

Ahmet Mert Nalbantoğlu,Deniz Yanık 대한치주과학회 2023 Journal of Periodontal & Implant Science Vol.53 No.5

Purpose: The aim of this study was to investigate the relationships between gingival thickness (GT) and keratinized gingiva width (KGW), papilla height (PH), and crown ratio (CR) by employing transgingival probing and an intraoral scanner (IOS). Methods: This cross-sectional study examined 360 maxillary anterior teeth from 60 patients. GT was assessed using transgingival probing with an endodontic spreader. KGW, CR, and PH were measured using an IOS. One-way analysis of variance, the Student’s t-test, and Spearman correlation coefficients were employed for statistical analysis. Results: Higher GT was significantly associated with thinner KGW in the central region (P=0.019). There was no statistically significant difference in GT between teeth (P=0.06). PH was lower in lateral teeth than in canines (P=0.047), with a PH of 2.99 mm in lateral teeth. The KGW was narrower in canines than in central teeth (P=0.007). A moderate correlation was observed between KGW and PH in the central region (P=0.01), while a weak negative correlation was found between KGW and CR (P=0.043). Conclusions: A moderate negative correlation was found between GT and KGW, as well as between PH and KGW in central teeth. In contrast, a weak negative correlation existed between CR and KGW. The PH (2.99 mm) was lower in lateral teeth than in canines. The traditional paradigm, which suggests a positive correlation between KGW and GT, was reevaluated by measuring KGW using an IOS.

An Improved Hybrid Feature Reduction for Increased Breast Cancer Diagnostic Performance

Ahmet Mert,Niyazi K l ç,Ayd n Akan 대한의용생체공학회 2014 Biomedical Engineering Letters (BMEL) Vol.4 No.3

AbstractPurpose Early and correct diagnosis of a disease is vital forthe success of treatment. Medical diagnostic decision supportsystem can be used to improve the accuracy of the traditionaldiagnosis. As such, various pattern recognition methods arestudied and applied to develop medical diagnostic decisionsupport system. In this study, the effects of dimensionalityreduction techniques with probabilistic neural network (PNN)on breast cancer classification are examined. Methods A hybrid method is proposed using the independentcomponent analysis (ICA) and the discrete wavelet transform(DWT) to reduce feature vectors of Wisconsin diagnosticbreast cancer (WDBC) data set. Two independent components(ICs), and one approximation coefficient of the DWT areused as a reduced feature vector to classify breast cancer usingPNN. Performance measures such as accuracy, sensitivity,specificity, Youden’s index and the receiver operatingcharacteristics (ROC) curve are computed to indicate theadvantages of the hybrid feature reduction. Results The proposed feature reduction approach using ICAand DWT improves the diagnostic capability of the PNNclassifier. The hybrid feature reduction has a higher diagnosticcapability than the original thirty features using PNN as aclassifier. Accuracy and sensitivity are 96.31% and 98.88%,while the results of the classification using the original thirtyfeatures are 92.09% and 95.52%. Conclusions Feature reduction approach using ICA andDWT together increases the performance measures of breast cancer classification using PNN, while reducing computational complexity.

High-rate Single-Frequency Precise Point Positioning (SF-PPP) in the detection of structural displacements and ground motions

Mert Bezcioglu,Cemal Ozer Yigit,Ahmet Anil Dindar,Ahmed El-Mowafy,Kan Wang 국제구조공학회 2024 Structural Engineering and Mechanics, An Int'l Jou Vol.89 No.6

This study presents the usability of the high-rate single-frequency Precise Point Positioning (SF-PPP) technique based on 20 Hz Global Positioning Systems (GPS)-only observations in detecting dynamic motions. SF-PPP solutions were obtained from post-mission and real-time GNSS corrections. These include the International GNSS Service (IGS)-Final, IGS real-time (RT), real-time MADOCA (Multi-GNSS Advanced Demonstration tool for Orbit and Clock Analysis), and real-time products from the Australian/New Zealand satellite-based augmentation systems (SBAS, known as SouthPAN). SF-PPP results were compared with LVDT (Linear Variable Differential Transformer) sensor and single-frequency relative positioning (SF-RP) solutions. The findings show that the SF-PPP technique successfully detects the harmonic motions, and the real-time productsbased PPP solutions were as accurate as the final post-mission products. In the frequency domain, all GNSS-based methods evaluated in this contribution correctly detect the dominant frequency of short-term harmonic oscillations, while the differences in the amplitude values corresponding to the peak frequency do not exceed 1.1 mm. However, evaluations in the time domain show that SF-PPP needs high-pass filtering to detect accurate displacement since SF-PPP solutions include trends and lowfrequency fluctuations, mainly due to atmospheric effects. Findings obtained in the time domain indicate that final, real-time, and MADOCA-based PPP results capture short-term dynamic behaviors with an accuracy ranging from 3.4 mm to 8.5 mm, and SBAS-based PPP solutions have several times higher RMSE values compared to other methods. However, after high-pass filtering, the accuracies obtained from PPP methods decreased to a few mm. The outcomes demonstrate the potential of the high-rate SF-PPP method to reliably monitor structural and earthquake-induced ground motions and vibration frequencies of structures.

The Effects of Melatonin on Postoperative Intraabdominal Adhesion Formation

Ahmet Hatipoglu,Zeliha Turkyılmaz,Selva Mert 연세대학교의과대학 2007 Yonsei medical journal Vol.48 No.4

Purpose: Postoperative intraabdominal adhesion formation is a major clinical problem. No previous study was found, reporting the relationship between adhesion formation and melatonin administration, but melatonin, a strong antioxidant, is recognized to have certain effects on the progression of adhesion formation mechanism. It was therefore decided to investigate the effects of melatonin on postoperative adhesion formation. Materials and Methods: A total number of 24 Spraque-Dawley rats were utilized. Three groups, described as: Group A, sham laparatomy (n=8), Group B, rats that underwent only ischemia-reperfusion (n=8) and Group C, rats that underwent ischemia- reperfusion and were given 10 mg/kg melatonin solution i.v. (n=8). For Groups B and C, the ileocolic vessels were clamped. Blood glutathione peroxidase levels of all study groups were assessed, then microscopic and macroscopic adhesion scores were evaluated. Results: Glutathione peroxidase levels of the melatonin-treated group were significantly higher and fibroblast proliferation and macroscopic adhesion scores were significantly lower, than in the melatonin-free group. Conclusion: The results of this study supported the hypothesis, that melatonin administration may prevent intraabdominal adhesions resulting from surgery.

The Triglyceride-Glucose Index Can Predict Long-Term Major Adverse Cardiovascular Events in Turkish Patients With High Cardiovascular Risk

Mert İlker Hayıroğlu,Tufan Çınar,Vedat Çiçek,Ali Palice,Görkem Ayhan,Ahmet İlker Tekkeşin 한국지질동맥경화학회 2022 지질·동맥경화학회지 Vol.11 No.3

Objective There is an evidence gap regarding the predictive accuracy of the triglyceride-glucose (TyG) index for long-term major adverse cardiovascular events (MACEs) in individuals with high cardiovascular risk. The aim of this investigation was to evaluate the predictive value of the TyG index for long-term MACEs in patients at high cardiovascular risk. Methods In total, 483 patients with high cardiovascular risk were included in this analysis. The study population was separated into 2 groups depending on the occurrence of long-term MACEs. The independent predictors of long-term MACEs in patients with high cardiovascular risk were investigated. The long-term prognostic value of the TyG index in these patients was evaluated in terms of MACEs. Results Age, male sex, diabetes mellitus, and the TyG index were demonstrated to be independent predictors of long-term MACE occurrence in patients with high cardiovascular risk. The TyG index was independently related to long-term MACEs in patients with high cardiovascular risk (hazard ratio, 1.003; 95% confidence interval [CI], 1.001–1.006; p=0.011). The receiver operating characteristic curve revealed that the optimum value of the TyG index to predict long-term MACEs in the overall study cohort was >9.68, with 65% sensitivity and 63% specificity (area under the curve, 0.71; 95% CI, 0.65–0.77; p<0.001). Conclusion The TyG index was demonstrated to be an independent predictor of long-term MACE occurrence in patients with high cardiovascular risk who had not been previously diagnosed with cardiovascular disease.

Escherichia Coli Infective Endocarditis Presented with Aorta-to-left Atrial Fistula and Mitral Valve Aneurysm Rupture: A Rare Clinical Finding

Tufan Cinar,Mert İlker Hayiroğlu,Vedat Çiçek,Mehmet Uzun,Ahmet Lütfullah Orhan 한국심초음파학회 2020 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.28 No.2

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Efficiency of MVP ECG Risk Score for Prediction of Long-Term Atrial Fibrillation in Patients With ICD for Heart Failure With Reduced Ejection Fraction

Levent Pay,Ahmet Çağdaş Yumurtaş,Ozan Tezen,Tuğba Çetin,Semih Eren,Göksel Çinier,Mert İlker Hayıroğlu,Ahmet İlker Tekkeşin 대한심장학회 2023 Korean Circulation Journal Vol.53 No.9

Background and Objectives: The morphology-voltage-P-wave duration (MVP) electrocardiography (ECG) risk score is a newly defined scoring system that has recently been used for atrial fibrillation (AF) prediction. The aim of this study was to evaluate the ability of the MVP ECG risk score to predict AF in patients with an implantable cardioverter defibrillator (ICD) and heart failure with reduced ejection fraction in long-term follow-up. Methods: The study used a single-center, and retrospective design. The study included 328 patients who underwent ICD implantation in our hospital between January 2010 and April 2021, diagnosed with heart failure. The patients were divided into low, intermediate and high-risk categories according to the MVP ECG risk scores. The long-term development of atrial fibrillation was compared among these 3 groups. Results: The low-risk group included 191 patients, the intermediate-risk group 114 patients, and the high-risk group 23 patients. The long-term AF development rate was 12.0% in the low-risk group, 21.9% in the intermediate risk group, and 78.3% in the high-risk group. Patients in the high-risk group were found to have 5.2 times higher rates of long-term AF occurrence compared to low-risk group. Conclusions: The MVP ECG risk score, which is an inexpensive, simple and easily accessible tool, was found to be a significant predictor of the development of AF in the long-term follow-up of patients with an ICD with heart failure with reduced ejection fraction. This risk score may be used to identify patients who require close follow-up for development and management of AF.

A Rare Cause of Syncope: Apical Biventricular Hypertrophic Cardiomyopathy Complicated by Atrial Flutter

Tufan Cinar,Süha Asal,Mert İlker Hayiroğlu,Nurgül Keser,Ahmet Lütfullah Orhan 한국심초음파학회 2020 Journal of Cardiovascular Imaging (J Cardiovasc Im Vol.28 No.3

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Upper Gastrointestinal Tract Polyps: What Do We Know About Them?

Buyukasik, Kenan,Sevinc, Mert Mahsuni,Gunduz, Umut Riza,Ari, Aziz,Gurbulak, Bunyamin,Toros, Ahmet Burak,Bektas, Hasan Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.7

Background: This study aimed to evaluate upper gastrointestinal polyps detected during esophago-gastroduodenoscopy tests. Materials and Methods: We conducted a retrospective analysis on data regarding 55,987 upper gastrointestinal endoscopy tests performed at the endoscopy unit of Istanbul Education and Research Hospital between January 2006 and June 2012. Results: A total of 66 upper gastrointestinal polyps from 59 patients were analyzed. The most common clinical symptom was dyspepsia, observed in 41 cases (69.5%). The localizations of the polyps were as follows: 29 in the antrum (43.9%), 15 in the corpus (22.7%), 11 in the cardia (16.7%), 3 in the fundus (4.54%), 3 in the second portion of the duodenum (4.54%), 2 in the bulbus (3.03%) and 3 in the lower end of the esophagus (4.54%). Histopathological types of polyps included hyperplastic polyps (44) (66.7%), faveolar hyperplasia (8) (12.1%), fundic gland polyps (4) (6.06%), squamous cell polyps (4) (6.06%), hamartomatous polyps (3) (4.54%), and pyloric gland adenoma (3) (4.54%). Histopathological analysis of the gastric mucosa showed chronic atrophic gastritis in 30 cases (50.84%), HP infection in 33 cases (55.9%) and intestinal metaplasia in 19 cases (32.20%). In 3 cases with multiple polyps, adenocarcinoma was detected in hyperplastic polyps. Conclusions: Among polypoid lesions of the upper gastrointestinal tract, the most common histological type is hyperplastic polyps. Generally, HP infection is associated with chronic atrophic gastritis and intestinal metaplasia. The incidence of adenocarcinoma tends to be higher in patients with multiple hyperplastic polyps.