Person: KAYA, AHMET
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Publication Metadata only Modified Y-configured stents with the waffle-cone technique by use of Solitaire (R) stent for patients with wide-necked bifurcation aneurysms(2015-08-01T00:00:00Z) Nas, Omer Fatih; Kacar, Emre; Kaya, AHMET; Erdogan, Cuneyt; Hakyemez, Bahattin; KAYA, AHMETEndovascular treatment of wide-necked bifurcation aneurysms can be challenging, despite improvements in endovascular techniques. Y stent-assisted coiling is one such technique, but this may not be technically feasible, especially in cases of acute angulation between the proximal and distal parent arteries, and may require use of -modified Y-configured stents with the waffle-cone technique-. We report three cases of wide-necked bifurcation aneurysms that were successfully treated by use of the Solitaire (R) stent.Publication Metadata only Radiosurgery, Gamma Knife Radiosurgery, Vestibular schwannomas, tumor volume, Diffusion Tensor Imaging, Apparent diffusion coefficient.(2021-11-01T00:00:00Z) Kaya, Ahmet; Çeşme, Dilek Hacer; Yurtsever, İsmail; Sarı, Lütfullah; Alkan, Gökberk; Seyithanoglu, Mehmet Hakan; KAYA, AHMET; YURTSEVER, İSMAİLPublication Metadata only Retrieval of a dislocated coil and stent-assisted coiling by Solitaire (R) stent during endovascutar treatment of an intracraniat aneurysm(2016-03-01T00:00:00Z) Nas, O. F.; Kacar, E.; Kaya, AHMET; Erdogan, C.; Hakyemez, B.; KAYA, AHMETPublication 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 Metadata only Tunneled Peritoneal Catheter Placement in Palliation of Malignant Ascites: A Study with Two Different Types of Catheters(2019-01-01T00:00:00Z) Kaya, AHMET; Nas, Omer F.; Erdogan, Cuneyt; KAYA, AHMETObjective(s). Malignant ascites (MA) is abnormal accumulation of fluid in the peritoneal cavity and has negative effects on the quality of life. The purpose of this retrospective study is to explore feasibility, safety and efficacy of tunneled peritoneal catheter placement using both peritoneal dialysis and hemodialysis catheters in the palliation of MA. Methods. Between October 2013-June 2016, thirty patients with resistent MA underwent tunneled peritoneal catheterisation in our interventional radiology department. Tunneled peritoneal catheter (TPC) was placed in 22 (n=22/30; %73) patients, tunneled hemodialysis catheter (THC) was placed in 8 patients (n=8/30; %27). Routine visits were scheduled for months 1, 3, 6, 9, and 12 of the catheterization, and the records were evaluated retrospectively. Results. The overall duration of catheterization varied from 2 to 334 days (mean 66.4 +/- 68.5, median: 57 days). Catheters remained intact in 29 patients (96.7%) until the endpoint. There was one (3.3%) malfunctioning catheter among both groups. Overall, four patients developed infection, which were classified into major (n=2/30, %6.7) and minor (n=2/30, %6.7) complications according to SIR criteria. Conclusion. Tunneled peritoneal catheterization using both TPCs and THCs provided a safe method with relatively high patency, and low infection and systemic complication rates in the palliation of MA.Publication Metadata only The gently pull-back technique for neck bypass in treatment of wide-necked internal carotid artery aneurysms: A report of three cases and review of the literature(2015-12-01T00:00:00Z) Kacar, Emre; Nas, Omer F.; Kaya, AHMET; Erdogan, Cuneyt; Kocaeli, Hasan; Hakyemez, Bahattin; KAYA, AHMETNeck bypass failure in endovascular treatment of wide-necked internal carotid artery (ICA) aneurysms may adversely affect the technical success of the procedure. We used the gently pull-back technique to bypass the aneurysm neck and access the distal parent artery during endovascular treatment in patients with wide-necked ICA aneurysms. In this technique, a loop was made in the aneurysm and the distal parent artery was reached by using a small diameter microguidewire and a microcatheter. After providing reliable distal access, the microguidewire was removed and the whole system which consists of the microcatheter was gently pulled back. Finally the microcatheter was straightened and the aneurysm neck was passed. After crossing the aneurysm neck, a flow-diverting stent treatment and stent-assisted coiling were performed in three cases with wide-necked ICA aneurysm. The gently pull-back technique is a simple and effective method which requires no extra intravascular device and helps to bypass the aneurysm neck through a small diameter microguidewire and a microcatheter. This technique may be useful for neck aneurysm bypass in endovascular treatment of wide-necked ICA aneurysms.Publication Metadata only Rare use of twin Solitaire (R) stents in the double waffle-cone technique for endovascular treatment of a wide-necked bifurcation aneurysm(2015-04-01T00:00:00Z) Nas, Omer Fatih; Kacar, Emre; Kaya, AHMET; Erdogan, Cuneyt; Hakyemez, Bahattin; KAYA, AHMETEndovascular treatment of wide-necked bifurcation aneurysms may be challenging. The waffle-cone technique can be used in these aneurysms in case of acute angulation between parent artery and distal artery of the aneurysm. Solitaire (R) stent (Ev3, Irvine, CA, USA) has the significant advantage of mitigating the potential complication risks. This study reports the second case in the literature in which endovascular treatment of a wide-necked bifurcation aneurysm with the double waffle-cone technique by using twin Solitaire (R) stents proved to be successful.Publication Metadata only 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, ALPAYIn 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.Publication Metadata only Choosing the appropriate side for subcutaneous port catheter placement in patients with mastectomy: ipsilateral or contralateral?(2017-06-01T00:00:00Z) Nas, Omer Fatih; Hacikurt, Kadir; Kaya, AHMET; Dogan, Nurullah; Sanal, Bekir; Ozkaya, Guven; Dundar, Halit Ziya; Erdogan, Cuneyt; KAYA, AHMETTo evaluate long-term clinical follow-up results of implanting subcutaneous port catheters (SPCs) on ipsilateral or contralateral with mastectomy side in patients with axillary lymph node dissection.Publication Metadata only Increased mean platelet volume associated with extent of slow coronary flow(2012-07-01T00:00:00Z) Isik, Turgay; Ayhan, Erkan; Uyarel, Huseyin; Ergelen, Mehmet; Tanboga, Ibrahim Halil; Kurt, Mustafa; Korkmaz, Ali Fuat; Kaya, Ahmet; Aksakal, Enbiya; SEVİMLİ, Serdar; KAYA, AHMETBackground: Slow coronary flow (SCF) is characterized by delayed opacification of epicardial coronary vessels. SCF can cause ischemia and sudden cardiac death. We investigated the association between presence and extent of SCF, and cardiovascular risk factors and hematologic indices.