Person: ÇEŞME, DİLEK HACER
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Publication Open Access Effectiveness of Diffusion Tensor Imaging in the Microstructural Evaluation of Corpus Callosum and Brain Parenchyma in Children with Neurofibromatosis Type I(2021-04-01T00:00:00Z) ÇEŞME, DİLEK HACER; ÇEŞME, DİLEK HACERObjective: To compare tractional anisotropy (FA) and mean diffusivity (MD) values obtained from corpus callosum (CC), basal ganglion, thalamus, frontal and parietal white matter in NF1 patients compared to the control group and to investigate the correlation with CC volume. Methods: Thirty three cases diagnosed with NF1 and 21 healthy control groups were included in the study. CC volume was measured in both groups. Using tensor imaging (DTI), MD and FA values were calculated from CC genu and splenium, globus pallidum, caudate nucleus, putamen, thalamus, parietal and frontal white matter. Results: CC volume increased significantly in cases with NF1. There was a significant difference in MD and FA values obtained from CC genu and splenium compared to the control group. MD values obtained from frontal and parietal white matter, globus pallidum, putamen, thalamus and caudate nucleus were significantly higher than the control group. FA values decreased in caudate nucleus and putamen while FA values in globus pallidum were higher than control group. There was a negative correlation between CC volume and MD values obtained from KK splenium, putamen, thalamus and caudate nucleus Conclusion: Increased MD in areas of involvement in NF1 cases can be explained by impaired myelination and demyelination. Heterogeneity in FA values suggests that it is caused by microstructural differences resulting from the breakdown of myelin sheaths or axonal disruption in different locations of the brain. In cases with NF1, DTI findings will help us to understand the occurrence of the disease and the physiopathology of clinical findings in more detail.Publication Open Access Diagnostic performance of apparent diffusion coefficient values for the differentiation of intrahepatic cholangiocarcinoma from gastrointestinal adenocarcinoma liver metastases(2021-12-22T00:00:00Z) Yilmaz, TEMEL FATİH; Gultekin, Mehmet Ali; Turk, Hacı Mehmet; Cesme, Dilek Hacer; Besiroglu, Mehmet; Simsek, Melih; Toprak, Huseyin; Alkan, ALPAY; YILMAZ, TEMEL FATİH; TÜRK, HACI MEHMET; ÇEŞME, DİLEK HACER; ŞİMŞEK, MELİH; ALKAN, ALPAY; TOPRAK, HÜSEYİNBackground: We aimed to investigate whether there is a difference between intrahepatic cholangiocarcinoma (IHCC) and liver metastases of gastrointestinal system (GIS) adenocarcinoma in terms of apparent diffusion coefficient (ADC) values. Patients and methods: From January 2018 to January 2020, we retrospectively examined 64 consecutive patients with liver metastases due to gastrointestinal system adenocarcinomas and 13 consecutive IHCC in our hospital's medical records. After exclusions, fifty-three patients with 53 liver metastases and 10 IHCC were included in our study. We divided the patients into two groups as IHCC and liver metastases of GIS adenocarcinoma. For mean apparent diffusion coefficient (ADCmean) values, the region of interests (ROI) was placed in solid portions of the lesions. ADCmean values of groups were compared. Results: The mean age of IHCC group was 62.50 ± 13.49 and mean age of metastases group was 61.15 ± 9.18. ADCmean values were significantly higher in the IHCC group compared to the metastatic group (p < 0.001). ROC curves method showed high diagnostic accuracy (AUC = 0.879) with cut-off value of < 1178 x 10-6 mm2/s for ADCmean (Sensitivity = 90.57, Specificity = 70.0, positive predictive value [PPV] = 94.1, negative predictive value [NPV] = 58.3) in differentiating adenocarcinoma metastases from IHCC. Conclusions: The present study results suggest that ADC values have a potential role for differentiation between IHCC and GIS adenocarcinoma liver metastases which may be valuable for patient management.Publication Open 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, MEHMETPurpose: 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.Publication Open Access Evaluation of Optical Radiation from Visual Pathways with Diffusion Tensor Imaging in Patients with Neurofibromatosis Type 1(2021-10-01T00:00:00Z) ÇEŞME, DİLEK HACER; ÇEŞME, DİLEK HACERObjective: It was investigated whether patients with neurofibromatosis type 1 (NF1) with and without optic glioma (OG) differed from the healthy control group in terms of diffusion tensor imaging (DTI) parameters obtained from optic radiation. Methods: Eighty three patients and 36 healthy controls followed with the diagnosis of NF1 were included in the study. Routine MRI and DTI were applied to all subjects. Fractional anisotropy (FA), mean diffusity (MD), radial diffusity (RD) and axial diffusity (AD) values were calculated by placing ROI on the right and left optic radiation on colored FA maps. Patients with OG detected by conventional magnetic resonance imaging (n=19) were classified as group 1, patients with NF1 without OG (n=64) were classified as group 2 and they were compared with the healthy control group in terms of DTI parameters. Results: The right and left optic radiation FA values of the patients in group 1 and group 2 were significantly different when compared with the healthy control group. Optical radiation FA values were significantly lower than healthy control group. MD values in group 1 patients with OG were significantly higher than healthy control group. Optic radiation RD values were significantly higher in group 1 and group 2 compared with healthy control group. Conclusion: There appears to be microstructural damage in optic radiation in patients with NF1 with or without OG. The idea that changes in FA values detected in optic radiation in visual pathways in patients with NF1 can be predicted in the early period of visual impairment is promising in terms of treatment planning and management.Publication Open Access Evaluation of toxic effects of chemotherapy in lung malignancies on cerebral white matter using diffusion tensor imaging(2022-05-04T00:00:00Z) Aydin, Sinem; Demir, Tarik; Turk, Haci Mehmet; Cesme, DİLEK HACER; Aliyev, Altay; Ali Gultekin, Mehmet; Fatih Yilmaz, Temel; Alkan, ALPAY; TÜRK, HACI MEHMET; ÇEŞME, DİLEK HACER; ALKAN, ALPAYBackground: Non-small cell lung cancer (NSCLC) is a leading cause of morbidity and mortality. Carboplatin and cisplatin based regimens are used in the treatment of NSCLC. The aim of the study was to find out whether there is a difference in white matter (WM) changes between two platinum-based chemotherapy agents using diffusion tensor imaging (DTI). Patients and methods: 25 patients who received chemotherapy for NSCLC and 27 age-matched healthy controls were enrolled in the study. Fractional anisotropy (FA), axial diffusivity (AD), mean diffusivity (MD) and radial diffusivity (RD) values of the study population were measured from 11 regions of interest in pre-chemotherapy and post-chemotherapy MRI data. Results: Cisplatin group showed a significant decrease in the FA of the inferior longitudinal fasciculus (P = 0.028). Carboplatin group showed a significant FA decrease and RD increase in the forceps minor (P = 0.022 and P = 0.011, respectively), and a significant reduction in AD and increase in MD in frontal white matter (WM) (P = 0.008 and P = 0.029, respectively). In comparison of post chemotherapy DTI values of the two groups, carboplatin group showed lower FA, and higher MD and RD values than cisplatin group in parieto-occipital WM (P = 0.034, P = 0.034, P = 0.029, respectively). Conclusions: The findings of the study suggest that subtle effects of chemotherapy detectable with DTI may emerge after the treatment. In addition, carboplatin regimen may have more impact on WM than cisplatin regimen.Publication Open Access Evaluation of Brainstem Subcortical Auditory Pathways with Diffusion Tensor Imaging After Gamma Knife Radiosurgery in Intracanalicular Vestibular Schwannoma(2021-01-01T00:00:00Z) Cesme, Dilek Hacer; Alkan, Alpay; Gultekin, Mehmet Ali; Sari, Lutfullah; Alkan, Gokberk; Seyithanoglu, Mehmet Hakan; Hatiboglu, Mustafa Aziz; ÇEŞME, DİLEK HACER; ALKAN, ALPAY; SEYİTHANOĞLU, MEHMET HAKAN; HATİBOĞLU, MUSTAFA AZİZObjective: To investigate changes in DTI (Diffusion Tensor Imaging) parameters in brainstem subcortical auditory pathways after Gamma Knife Radiosurgery (GKR) in patients with intracanalicular vestibular schwannoma (ICVS) and to analyze the relationship between tumor volume and ADC (apparent diffusion coefficient) and FA (fractional anisotropy) values. Method: Seventeen patients with ICVS were evaluated before and after GKR. ADC and FA values of the lateral lemniscus (LL) and inferior colliculus (IC) and tumor volume were calculated. Patients who responded to GKR were classified as Group 1 and those who did not respond adequately as Group 2. The relationship between ADC and FA values and changes in tumor volume were analyzed. Results: Tumor volume significantly decreased after GKR. ADC values obtained from the tumor increased after GKR (p:0.002). There was no significant difference in LL and IC before and after GKR in terms of FA and ADC values (n:17). There was a positive correlation between response to treatment and contralateral LL ADC values after GKR (p=0.005, r:0.652). There was a negative correlation between contralateral IC FA values after GKR and response to treatment (p=0.017, r: -0.568). There was a significant difference between Groups 1 and 2 in regards to contralateral LL ADC (p=0.03) and IC FA values (p=0.017). Conclusion: Since the cochlear nerve and subcortical auditory pathways have low regeneration potential after nerve damage, ADC and FA changes in LL and IC may be explained with the presence of intracanalicular tumors prior to GKR. Since GKR does not cause additional damage to the subcortical auditory pathways at the brainstem level, we think that GKR is a noninvasive treatment method that can be used safely in patients with ICVS.Publication Open 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 AZİZObjective 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.Publication Open Access Importance of Pre-treatment Fractional Anisotropy Value in Predicting Volumetric Response in Patients with Meningioma Treated with Gamma Knife Radiosurgery.(2021-01-28T00:00:00Z) Cesme, Dilek Hacer; Alkan, Alpay; Sari, Lutfullah; Yabul, Fatma; Temur, Hafize Otcu; Aykan, Mahmut Esat; Hatiboglu, Mustafa Aziz; Seyithanoglu, Mehmet Hakan; ÇEŞME, DİLEK HACER; ALKAN, ALPAY; SEYİTHANOĞLU, MEHMET HAKAN; HATİBOĞLU, MUSTAFA AZİZBackground: The importance of pre-treatment Diffusion Tensor Imaging (DTI) parameters in determining the response to treatment after radiosurgery in patients with meningioma has not yet been clearly revealed. Objective: This study was conducted to determine tumor volume changes in terms of radiological response in patients with meningioma treated with Gamma Knife Radiosurgery (GKR) and to analyze the relationship between Total Tumor Volume (TTV) and Diffusion Tensor Imaging (DTI) parameters. In addition, we investigated whether the response to treatment can be predicted by pre-radiosurgery DTI findings. Methods: Fifty-four patients were assessed using MRI and DTI before and after GKR. Mean Diffusivity (MD), Fractional Anisotropy (FA), Radial Diffusivity (RD), and TTV of tumour were determined. Patients with 10% or more decrease in TTV after GKR were classified as group 1 and those with less than 10% decrease in volume or increase in volume were considered group 2. The relationships between MD, RD, and FA values and TTV were investigated. Results: A decrease of 46.34% in TTV was detected in group 1 after GKR, while TTV increased by 42.91% in group 2. The lowest pre-treatment FA value was detected in group 1. In addition, after GKR, FA values showed a significant increase in group 1. MD and RD values increased in both groups after radiosurgery. There was a negative correlation between pre-treatment FA, RD, and MD values after radiosurgery. Conclusion: Detection of low FA values due to the poor fiber content in meningioma before radiosurgery may be a guide in predicting the response to treatment. Further studies are required to have a better understanding of the relationship between pre- and post-treatment follow-up FA values and tumor volume in determining the efficacy of GKR in patients with meningioma.Publication Open Access Effectiveness of Virtual Bronchoscopy in Evaluation of Centrally Located Lung Cancer(2021-04-01T00:00:00Z) ÇEŞME, DİLEK HACER; ÇEŞME, DİLEK HACERObjective: The aim of this study was to compare virtual bronchoscopy (VB) with multi-slice CT (MSCT) in the diagnosis of centrally located lung cancer and to investigate the effectiveness of VB in the diagnosis of the radiologist. Methods: These patients had central lung mass detected during thorax tomography and were diagnosed as having centrally located lung cancer by histopathological examination. Detection and localization of lesions were determined by MSCT and VB. In addition, the evaluation time was determined in seconds with an electronic stopwatch. Results: The mean age of 32 patients included in the study was 58.14 +/- 15.09. Centrally located squamous cell carcinoma (n=19) and small cell carcinoma (n=13) were included. Eighteen (54.8%) patients were male and 14 (47.6%) were female. All patients diagnosed as having centrally located lung cancer detected by MSCT were also detected by VB (100%). In the evaluation of patients with MSCT and VB; obstruction and/or lesion and their localization completely overlapped. The mean duration of MSCT evaluation of the patients was determined as 58.7 sec, and the mean duration of VB assessment was 549.9 sec. The mean VB evaluation duration was found to be statistically significantly longer than the mean MSCT evaluation duration. Conclusion: Virtual bronchoscopy does not provide a significant additional contribution to MSCT in the diagnosis of centrally located malignant lung tumor. We think that using VB for diagnosis and navigation will be important in terms of efficiency especially in selected patients due to its low specificity and high sensitivity.