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GÜLTEKİN, MEHMET ALİ

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MEHMET ALİ
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2019 - 201912020 - 20219
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    PublicationOpen Access
    Diffusion Tensor Imaging Can Discriminate the Primary Cell Type of Intracranial Metastases for Patients with Lung Cancer.
    (2021-03-04T00:00:00Z) Bilgin, Sabriye Sennur; Gultekin, Mehmet Ali; Yurtsever, Ismail; Yilmaz, Temel Fatih; Cesme, Dilek Hacer; Bilgin, Melike; Topcu, Atakan; Besiroglu, Mehmet; Turk, Haci Mehmet; Alkan, ALPAY; Bilgin, Mehmet; GÜLTEKİN, MEHMET ALİ; YURTSEVER, İSMAİL; YILMAZ, TEMEL FATİH; ÇEŞME, DİLEK HACER; TÜRK, HACI MEHMET; ALKAN, ALPAY; BİLGİN, MEHMET
    Purpose: Histopathological differentiation of primary lung cancer is clinically important. We aimed to investigate whether diffusion tensor imaging (DTI) parameters of metastatic brain lesions could predict the histopathological types of the primary lung cancer. Methods: In total, 53 patients with 98 solid metastatic brain lesions of lung cancer were included. Lung tumors were subgrouped as non-small cell carcinoma (NSCLC) (n = 34) and small cell carcinoma (SCLC) (n = 19). Apparent diffusion coefficient (ADC) and Fractional anisotropy (FA) values were calculated from solid enhanced part of the brain metastases. The association between FA and ADC values and histopathological subtype of the primary tumor was investigated. Results: The mean ADC and FA values obtained from the solid part of the brain metastases of SCLC were significantly lower than the NSCLC metastases (P < 0.001 and P = 0.003, respectively). ROC curve analysis showed diagnostic performance for mean ADC values (AUC=0.889, P = < 0.001) and FA values (AUC = 0.677, P = 0.002). Cut-off value of > 0.909 × 10-3 mm2/s for mean ADC (Sensitivity = 80.3, Specificity = 83.8, PPV = 89.1, NPV = 72.1) and > 0.139 for FA values (Sensitivity = 80.3, Specificity = 54.1, PPV = 74.2, NPV= 62.5) revealed in differentiating NSCLC from NSCLC. Conclusion: DTI parameters of brain metastasis can discriminate SCLC and NSCLC. ADC and FA values of metastatic brain lesions due to the lung cancer may be an important tool to differentiate histopathological subgroups. DTI may guide clinicians for the management of intracranial metastatic lesions of lung cancer.
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    Meme kanseri beyin metastazlarının moleküler subgruplarının difüzyon tensor görüntüleme ile değerlendirilmesi
    (2019-04-27T00:00:00Z) Yurtsever, İsmail; Gültekin, Mehmet Ali; Yılmaz, Temel Fatih; Türk, Hacı Mehmet; Alkan, Alpay; YURTSEVER, İSMAİL; GÜLTEKİN, MEHMET ALİ; YILMAZ, TEMEL FATİH; TÜRK, HACI MEHMET; ALKAN, ALPAY
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    PublicationOpen Access
    Diffusion Tensor Imaging Features of the Auditory Pathways in Patients With Vestibular Schwannoma After Gamma Knife Radiosurgery
    (2021-03-01T00:00:00Z) ÇEŞME, DİLEK HACER; ALKAN, ALPAY; GÜLTEKİN, MEHMET ALİ; SARI, LÜTFULLAH; Alkan, Gokberk; KAYA, AHMET; MAYADAĞLI, Alpaslan; Akdur, Kerime; UYSAL, ÖMER; HATİBOĞLU, MUSTAFA AZİZ; ÇEŞME, DİLEK HACER; ALKAN, ALPAY; GÜLTEKİN, MEHMET ALİ; SARI, LÜTFULLAH; KAYA, AHMET; MAYADAĞLI, ALPASLAN; UYSAL, ÖMER; HATİBOĞLU, MUSTAFA AZİZ
    Objective In this study, we aimed to investigate whether there is any change in diffusion tensor imaging (DTI) parameters in ipsilateral and contralateral auditory pathways after Gamma Knife radiosurgery (GKR) in patients with vestibular schwannoma (VS) and the relationship between radiosurgery variables. Methods Sixty-six patients were evaluated with MRI and DTI before and after GKR. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured from the bilateral lateral lemniscus (LL), inferior colliculus (IC), medial geniculate body (MGB), and Heschl's gyrus (HG). Results There was no significant difference in ADC and FA values obtained from bilateral LL, IC, and MGB before and after radiosurgery. However, there was a significant difference between pretreatment and post-radiosurgery contralateral HG ADC values. The ADC values obtained from the contralateral HG and IC positively correlated with the duration after radiosurgery. As the duration after radiosurgery increases, the difference between the ADC values obtained from ipsilateral and contralateral HG also increases. Conclusion The high ADC values in the contralateral HG after radiosurgery may indicate microstructural alterations such as demyelination and axonal loss. Radiation exposure doses to the brainstem and cochlea are the most important factors that can cause microstructural damage to the auditory pathways. When planning radiosurgery, extreme care should be taken to prevent the harmful effects of radiation on the auditory pathways.
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    The Utility and Efficiency of Diffusion Tensor Imaging Values to Determine Epidermal Growth Factor Receptor Gene Mutation Status in Brain Metastasis from Lung Adenocarcinoma; A Preliminary Study
    (2021-02-01T00:00:00Z) Gültekin, Mehmet Ali; Alkan, Alpay; Yılmaz, Temel Fatih; Yurtsever, İsmail; Atasoy, Bahar; Aliyev, Altay; GÜLTEKİN, MEHMET ALİ; TÜRK, HACI MEHMET; YURTSEVER, İSMAİL; YILMAZ, TEMEL FATİH; ALKAN, ALPAY
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    Relationship with programmed cell death ligand 1 (PD-L1) and DTI features in brain metastases of non-small cell lung cancer; Preliminary study.
    (2021-02-17T00:00:00Z) Yurtsever, İsmail; Yilmaz, Temel Fatih; Turk, Hacı Mehmet; Gultekin, Mehmet Ali; Besiroglu, Mehmet; Cesme, DİLEK HACER; Shbair, Abdallah T M; Alkan, ALPAY; YILMAZ, TEMEL FATİH; YURTSEVER, İSMAİL; TÜRK, HACI MEHMET; GÜLTEKİN, MEHMET ALİ; ÇEŞME, DİLEK HACER; ALKAN, ALPAY
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    Brain Diffusion Tensor Imaging Findings in Hashimoto-s Thyroiditis.
    (2020-11-06T00:00:00Z) Gultekin, MA; Yurtsever, I; Cesme, DİLEK HACER; Karaman, O; Yilmaz, TF; Alkan, ALPAY; GÜLTEKİN, MEHMET ALİ; ÇEŞME, DİLEK HACER; KARAMAN, ÖZCAN; YURTSEVER, İSMAİL; YILMAZ, TEMEL FATİH; ALKAN, ALPAY
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    DIFFERENTIATION OF BRAIN METASTASES FROM BRAIN MRI WITH DEEP CNN
    (2021-02-17T00:00:00Z) GÜLTEKİN, MEHMET ALİ; PEKER, ABDUSSELİM ADİL; OKTAY, AYŞE BETÜL; TÜRK, HACI MEHMET; ÇEŞME, DİLEK HACER; Shbair, Abdallah; YILMAZ, TEMEL FATİH; KAYA, AHMET; YASİN, AYŞE İREM; ŞEKER, MESUT; MAYADAĞLI, ALPASLAN; ALKAN, ALPAY; GÜLTEKİN, MEHMET ALİ; PEKER, ABDUSSELİM ADİL; TÜRK, HACI MEHMET; YILMAZ, TEMEL FATİH; YASİN, AYŞE İREM; ŞEKER, MESUT; ALKAN, ALPAY
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    Diffusion Tensor Imaging of Brain Metastases in Patients with Breast Cancer According to Molecular Subtypes.
    (2020-06-21T00:00:00Z) Turk, HM; Sari, L; Yurtsever, I; Yabaci, A; Peker, AA; Alkan, ALPAY; YURTSEVER, İSMAİL; GÜLTEKİN, MEHMET ALİ; TOPRAK, HÜSEYİN; TÜRK, HACI MEHMET; YABACI TAK, AYŞEGÜL; ALKAN, ALPAY
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    The effectiveness of cerebellar lesions on neurocognitive functions in children with neurofibromatosis Type 1: Diffusion tensor imaging features
    (2021-04-01T00:00:00Z) Toprak, Mekiya Filiz; Çeşme, Dilek Hacer; Kaya, Ahmet; Gültekin, Mehmet Ali; Aydın, Sinem; Uygur Şahin, Türkan; Alkan, Alpay; ÇEŞME, DİLEK HACER; KAYA, AHMET; GÜLTEKİN, MEHMET ALİ; UYGUR ŞAHİN, TÜRKAN; ALKAN, ALPAY
    In children with Neurofibromatosis type 1 (NF1), hamartomatous lesions called FASI (focal areas of signal intensity) on brain MRI are common. The relationship between neurocognitive functions and the presence of cerebellar FASI in NF1 children is a controversial issue. Our aim in this study is to investigate whether there is a difference in fractional anisotropy (FA) and mean diffusivity (MD) values in children with NF1 with and without cerebellum FASI, and to analyze its effect on neurocognitive functions. Twenty-seven patients children were assessed using Diffusion Tensor Imaging (DTI) and MRI. According to MRI features, we classified children with NF1 as group 1 with FASI (n=14) in the cerebellum, group 2 without FASI (n=13). The WISC-R scale (a revised form of the Wechsler intelligence scale for children) was used to analyze cognitive functions. MD and FA values were measured from cerebellar FASI and white matter. The relationship between neurocognitive function test scores and FA and MD values was investigated. There was a significant difference between group 1 and group 2 in terms of MD and FA values of the cerebellum. Verbal and performance test scores were lower in group 1 and group 2. The MD values obtained from the cerebellum were positively correlated with the full-scale intelligence quotient (IQ), Verbal IQ, and Performance IQ. There was a significant difference between group 1 and group 2 in terms of information, vocabulary, digit span, picture arrangement. DTI changes in the cerebellum are associated with demyelination and loss of axonal integrity in the white matter pathways responsible for some neurocognitive functions. We think that the presence of cerebellar FASI in children with NF1 does not contribute to the severity of neurocognitive impairment.
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    Apparent Diffusion Coefficient Values for Neuroendocrine Liver Metastases.
    (2020-11-07T00:00:00Z) Gultekin, MA; Cesme, DH; Yurtsever, I; Turk, HM; Seker, M; Besiroglu, M; Alkan, ALPAY; GÜLTEKİN, MEHMET ALİ; TÜRK, HACI MEHMET; YURTSEVER, İSMAİL; ÇEŞME, DİLEK HACER; ALKAN, ALPAY