Person: SEVEN, GÜLSEREN
5 results
Search Results
Now showing 1 - 5 of 5
Publication Open Access Differentiating Gastrointestinal Stromal Tumors from Leiomyomas Using a Neural Network Trained on Endoscopic Ultrasonography Images.(2021-10-07T00:00:00Z) Seven, GÜLSEREN; Silahtaroglu, Gokhan; Seven, Ozden Ozluk; Senturk, Hakan; SEVEN, GÜLSERENBackground: Endoscopic ultrasonography (EUS) is crucial to diagnose and evaluate gastrointestinal mesenchymal tumors (GIMTs). However, EUS-guided biopsy does not always differentiate gastrointestinal stromal tumors (GISTs) from leiomyomas. We evaluated the ability of a convolutional neural network (CNN) to differentiate GISTs from leiomyomas using EUS images. The conventional EUS features of GISTs were also compared with leiomyomas. Patients and methods: Patients who underwent EUS for evaluation of upper GIMTs between 2010 and 2020 were retrospectively reviewed, and 145 patients (73 women and 72 men; mean age 54.8 ± 13.5 years) with GISTs (n = 109) or leiomyomas (n = 36), confirmed by immunohistochemistry, were included. A total of 978 images collected from 100 patients were used to train and test the CNN system, and 384 images from 45 patients were used for validation. EUS images were also evaluated by an EUS expert for comparison with the CNN system. Results: The sensitivity, specificity, and accuracy of the CNN system for diagnosis of GIST were 92.0%, 64.3%, and 86.98% for the validation dataset, respectively. In contrast, the sensitivity, specificity, and accuracy of the EUS expert interpretations were 60.5%, 74.3%, and 63.0%, respectively. Concerning EUS features, only higher echogenicity was an independent and significant factor for differentiating GISTs from leiomyomas (p < 0.05). Conclusions: The CNN system could diagnose GIMTs with higher accuracy than an EUS expert and could be helpful in differentiating GISTs from leiomyomas. A higher echogenicity may also aid in differentiation.Publication Metadata only Effects of tissue cytomegalovirus quantitative polymerase chain reaction in the management of ulcerative colitis flare-ups: Should we wave aside?(2021-12-03T00:00:00Z) Kochan, Koray; Seven, Gulseren; Bas, Suleyman; Kiremitci, Sercan; Gecer, Melin; Senturk, Hakan; BİBERCİ KESKİN, ELMAS; SEVEN, GÜLSERENPublication Metadata only Evaluation of Ki67 index in endoscopic ultrasound-guided fine needle aspiration samples for the assessment of malignancy risk in gastric gastrointestinal stromal tumors.(2020-10-05T00:00:00Z) Senturk, Hakan; Seven, GÜLSEREN; Kochan, KORAY; Caglar, Erkan; Kiremitci, Sercan; Koker, Ibrahim Hakki; SEVEN, GÜLSEREN; KOÇHAN, KORAY; KÖKER, İBRAHİM HAKKI; ŞENTÜRK, HAKANBackground: The risk of malignancy in resected gastrointestinal stromal tumors (GISTs) depends on tumor size, location, and mitotic index. Reportedly, the Ki67 index has a prognostic value in resected GISTs. We aimed to analyze the accuracy of endoscopic ultrasound (EUS)-guided fine needle aspiration (FNA) samples with reference to Ki67 index, using surgical specimens as the gold standard. Methods: Fifty-five patients who underwent EUS-FNA followed by surgical resection for gastric GISTs were retrospectively analyzed. Patients’ age and sex; tumors’ size and location; mitotic index, cell type, cellularity, pleomorphism, presence of ulceration, hemorrhage, necrosis, mucosal or serosal invasion, growth pattern, and Ki67 index based on pathology were investigated. Results: Location in fundus, ulceration, hemorrhage, mucosal invasion, and Ki67 index in surgical specimens were significant in predicting high-risk groups (P < 0.05) on univariate analysis. resence of bleeding (P = 0.034) and the Ki67 index (P = 0.018) were the only independent significant factors in multivariate analysis. The optimal cutoff level of Ki67 was 5%, with 88.2% sensitivity and 52.8% specificity (P = 0.021). The mean Ki67 index was lower in EUS-FNA samples than in surgical specimens [2% (1-15) vs. 10% (1-70), P = 0.001]. The rank correlation coefficient value of Ki67 was 0.199 (P = 0.362) between EUS-FNA and surgical samples and showed no reliability for EUS-FNA samples. Conclusion: The Ki67 index in resected specimens correlated with high-risk GISTs, although it had no additive value to the current criteria. The Ki67 index in EUS-guided FNA samples is not a reliable marker of proliferation in GISTs.Publication Metadata only Use of Artificial Intelligence in the Prediction of Malignant Potential of Gastric Gastrointestinal Stromal Tumors.(2021-02-06T00:00:00Z) Ince, Ali Tuzun; Seven, GÜLSEREN; Senturk, Hakan; Kochan, Koray; Arici, Dilek Sema; SEVEN, GÜLSEREN; İNCE, ALİ TÜZÜN; ŞENTÜRK, HAKANPublication Open Access Correlation of Endoscopic Ultrasonography Features with the Mitotic Index in 2- to 5-cm Gastric Gastrointestinal Stromal Tumors(2021-04-01T00:00:00Z) Seven, Gulseren; Arici, Dilek Sema; Senturk, HAKAN; SEVEN, GÜLSEREN; ŞENTÜRK, HAKANBackground: Predicting the malignancy potential of gastrointestinal stromal tumor (GIST) before resection could improve patient management strategies as gastric GISTs with a low malignancy potential can be safely treated endoscopically, but surgical resection is required for those tumors with a high malignancy potential. This study aimed to evaluate endoscopic ultrasound (EUS) features of 2- to 5-cm gastric GISTs that might be used to predict their mitotic index using surgical specimens as the gold standard. Patients and methods: Forty-nine patients (30 females and 19 males; mean age 55.1 ± 12.7 years) who underwent EUS examinations, followed by surgical resections of 2- to 5-cm gastric GISTs, were retrospectively reviewed. Results: The mean tumor size was 3.44 ± 0.97 (range 2.1-5.0) cm. A univariate analysis revealed no significant differences in age, sex, and tumor location in the low mitotic index and high mitotic index groups (all p > 0.05). In terms of EUS features, there were no significant differences in the mitotic indexes with respect to the shape, surface lobulation, border regularity, echogenicity, homogeneity, growth patterns, presence of mucosal ulceration, hyperechogenic foci, anechoic spaces, and hypoechoic halos (all p > 0.05). However, the tumor size was larger in the high mitotic index group than that in the low mitotic index group (3.97 ± 1.05 vs. 3.27 ± 0.9 cm, p = 0.03). Conclusion: Conventional EUS features are not reliable for predicting the mitotic index of 2- to 5-cm gastric GISTs. Further modalities for predicting the mitotic index are needed to prevent unnecessary surgical resections in patients with a low risk of malignancy.