Person: HAKYEMEZ, BAHATTİN
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HAKYEMEZ
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Publication New technique: The use of the thrive sequence in the follow-up of patients who received endovascular intracranial aneurysm treatment(Springer, 2020-09-11) Mırcık, Emre; Hakyemez, Bahattin; HAKYEMEZ, BAHATTİN; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı; 0000-0002-3425-0740; AAI-2318-2021Purpose To determine the diagnostic accuracy of 3D time of flight MR angiography (TOF-MRA), contrast enhanced MR angiography (CE-MRA), and T1-weighted high-resolution isotropic volume examination (THRIVE) at 3 T for the evaluation of intracranial aneurysm occlusion after endovascular treatment and to evaluate the usability of the THRIVE sequence in endovascular treatment follow-up. Methods In 3 T MR follow-up examinations of 66 aneurysms in 50 patients treated endovascularly, 3D TOF-MRA (index test), THRIVE (index test), and CE-MRA (reference standard) examinations were performed in a retrospective consecutive case series. Source images were classified as class 1, class 2, and class 3 according to the Raymond criteria using MIP (maximum intensity projection) techniques. The compatibility between sequences was evaluated with the Kappa test. The sensitivity and specificity were also calculated. Results In the evaluation of THRIVE and CE-MRA sequences, compatibility was determined in 61 cases in total, with an overall fit of 61/66 (92.42%). A statistically significant correlation was found between THRIVE and CE-MRA (p< 0.001,kappa= 0.800). In the evaluation of TOF and CE-MRA sequences, compatibility was determined in 54 cases in total, and the overall fit was 54/66 (81.8%). A statistically significant agreement was found between TOF and CE-MRA (p< 0.001,kappa= 0.502). Assuming that CE-MRA is a reference standard, the sensitivity and specificity of the TOF sequence were 44.4% and 97.9%, respectively, and the sensitivity and specificity of the THRIVE sequence were 77.8% and 97.9%, respectively. Conclusion The THRIVE sequence can be used as a noncontrast method for monitoring endovascularly treated intracranial aneurysms.Publication Causes of ischemic stroke in patients with atrial fibrillation(Türk Nöroloji Derneği, 2020-12-01) Dinc, Yasemin; Bakar, Mustafa; Hakyemez, Bahattin; Dinç, Yasemin; DİNÇ, YASEMİN; Bakar, Mustafa; BAKAR, HACI MUSTAFA; Hakyemez, Bahattin; HAKYEMEZ, BAHATTİN; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı.; AAI-2318-2021; IUQ-6999-2023Objective: Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting 1% of the adult population. However, ischemic strokes in patients with AF can be triggered by alternative mechanisms, especially in high-risk patients with additional vascular risk factors. In some patients, atherothrombotic mechanisms may cause stroke, and AF may be incidental or a symptom of atherosclerotic disease. In this case, it may be difficult to distinguish cardioembolic stroke from stroke due to large artery atherosclerosis. The aim of this study was to determine the causes of non-cardioembolic ischemic stroke in patients with non-valvular AF and to determine the risk factors for craniocervical atherosclerotic stenosis.Materials and Methods: This study identified risk factors for craniocervical atherosclerotic stenosis in patients followed up at the Uludag University Faculty of Medicine Department of Neurology with a diagnosis of ischemic stroke and non-valvular AF. In this study, 180 patients who were followed up with a diagnosis of non-valvular AF and acute ischemic stroke between January 1st, 2019 - March 1st 2020, in Uludag University Faculty of Medicine Department of Neurology, were retrospectively included.Results: In this study, the non-cardiac stroke rate was 20% in patients with non-valvular AF who had acute ischemic stroke. Ischemic stroke due to large vessel atherosclerosis was found in 14.4% of these patients, and 9.5% of all patients with AF were stented. When dermographic features, clinical features, and risk factors were analyzed for craniocervical atherosclerotic stenosis, a significant statistical result was obtained with male sex (p=0.020) and smoking (p<0.001).Conclusion: Stroke is a heterogeneous group of diseases caused by many complex mechanisms. Prevention of stroke recurrence is possible by starting effective treatment early. The presence of critical artery stenosis in a patient with acute ischemic stroke with AF causes stroke recurrence and this relapse cannot be prevented by anticoagulant treatment. Angiographic evidence also revealed ethnic and racial differences in patients with acute ischemic stroke. Therefore, more precise information can be obtained through prospective studies in our population.Publication Evaluation of risk factors associated with stroke recurrence in patients with minor ischemic stroke(Türk Nöroloji Derneği, 2022-03-01) Dinç, Yasemin; Akarsu, Emel Oğuz; Hakyemez, Bahattin; Bakar, Mustafa; DİNÇ, YASEMİN; OĞUZ AKARSU, EMEL; HAKYEMEZ, BAHATTİN; Bakar, Mustafa; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Nöroloji Anabilim Dalı; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı; 0000-0002-3425-0740; IUQ-6999-2023; IZQ-0662-2023; IWC-9957-2023; AAI-2318-2021; EKN-8251-2022Objective: Recurrent ischemic stroke (RIS) is a major threat CO patients with IS. The risk of RIS in patients with minor IS (MIS) is 10-13% in the first 3 months. Despite the advanced examination and treatment of the patients, RIS is still common. It is important to know which risk factors cause RIS in order to rake some precautions. The aim of this study is to determine the risky group by determining the demographic, clinical and radiological features associated with RIS in patients with MIS.Materials and Methods: We included 310 patients diagnosed as having acute IS (AIS) by Bursa Uludag University Faculty of Medicine Department of Neurology between 01.01.2019 and 01.01.2020, retrospectively.Results: When clinical, radiological and dermogrophic features were analyzed between patients with and without RIS, there were statistically significant differences between groups in terms of the presence of coronary artery disease (CAD), atherosclerotic vascular disease, anterior circulation stroke, craniocervical atherosclerotic stenosis, atherosclerotic stenosis in the anterior circulation, atherosclerotic stenosis of the symptomatic internal carotid artery (ICA), atherosclerotic stenosis in the asymptomatic ICA and performing carotid artery scenting. When significant variables were analyzed by using binary logistic regression in patients with MIS, it was found that the most significant variables were CAD and asymptomatic ICA stenosis.Conclusion: In our study, the risk factors associated with RIS in patients with MIS were the presence of CAD and asymptomatic ICA stenosis. Atherosclerosis is a systemic disease and therefore craniocervical atherosclerotic stenosis may be multiple. Angiographic evidence has also revealed ethnic and racial differences in patients with AIS. For this reason, more precise information can be obtained with prospective studies to be conducted in our own population.Publication The relationship between early neurological deterioration, poor clinical outcome, and venous collateral score in cerebral venous sinus thrombosis(Wolters Kluwer Medknow Publications, 2021-07-01) Dinç, Yasemin; Özpar, Rıfat; Hakyemez, Bahattin; Bakar, Mustafa; DİNÇ, YASEMİN; ÖZPAR, RİFAT; HAKYEMEZ, BAHATTİN; BAKAR, HACI MUSTAFA; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı; Bursa Uludağ Üniversitesi/Tıp Fakültesi/ Nöroloji Anabilim Dalı; 0000-0001-6649-9287; 0000-0002-3425-0740; 0000-0003-0342-5939; IWC-9957-2023; AAH-5062-2021; AAI-2318-2021; EKN-8251-2022Background and Purpose: Cerebral venous sinus thrombosis (CVST) is one of the rare causes of cerebrovascular disease and has an extremely heterogeneous prognosis. The aim of this study was to investigate the potential relationship between early neurological deterioration, poor clinical outcome in CVST and the venous collateral score. Materials and Methods: A total of 121 patients diagnosed with CVST between 2010 and 2020 were retrospectively included. The demographic, clinical, and radiological findings related to venous sinus thrombosis and early neurological deterioration were investigated in relation to the clinical outcome. Results: The factors associated with early neurological deterioration were superior sagittal sinus thrombosis (P < 0.001), sinus rectus thrombosis (P = 0.031), parenchymal lesions (P < 0.001), and venous collateral score (P < 0.001). The factors associated with poor clinical outcome were superior sagittal sinus thrombosis (P < 0.001), cortical vein thrombosis (P < 0.001), venous collateral score (P < 0.001), and initial clinical symptoms. Binary logistic regression analyses revealed poor clinical outcome as a significant variable, with a venous collateral scale of 0 or 1 as a risk factor for a poor outcome (significance of the model P < 0.001). Conclusion: Early neurologic deterioration and poor clinical outcome may occur due to poor collateralization in CVST. Identifying the subgroup of CVST patients at risk of clinical deterioration is therefore important. This study highlights the clinical importance of venous collaterals; however, larger prospective multicenter studies are required to confirm the relationship with venous collaterals in patients with CVST.Publication Evaluation of clinical, radiological, and demographic characteristics of juxtacortical hemorrhages in cerebral venous thrombosis(Türk Nöroloji Derneği, 2021-12-01) Dinç, Yasemin; Özpar, Rıfat; Bakar, Mustafa; Hakyemez, Bahattin; DİNÇ, YASEMİN; ÖZPAR, RİFAT; BAKAR, HACI MUSTAFA; HAKYEMEZ, BAHATTİN; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Nöroloji Anabilim Dalı; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı; 0000-0001-6649-9287; 0000-0002-3425-0740; IUQ-6999-2023; AAH-5062-2021; EKN-8251-2022; AAI-2318-2021Objective: Cerebral venous thrombosis (CVT) is a rare form of cerebrovascular disease. Intracranial hemorrhage may occur in 40% of the patients with CVT. The morphology of the intracranial hemorrhages ranges from small juxtacortical hemorrhages (JH) to large parenchymal hematomas. Although it has been suggested that JH is a characteristic of CVT, studies examining the relationship between JH and CVT are limited. In this study, it was aimed to determine the clinical, radiological, and demographic characteristics of JH in patients with CVT.Materials and Methods: In this study, a total of 157 patients who were followed up with the diagnosis of CVT between 2015 and 2021 were included retrospectively. Patients were categorized as, those with and without JH. Variables associated with JH were determined by comparing the demographic, clinical, and radiological characteristics, CVT etiologies and clinical outcomes of the patients.Results: When the clinical, demographic, and radiological characteristics of the patients with and without JH were compared; female gender (p=0.037), clinical initial symptom (0.003), early superior sagittal sinus (SSS) thrombosis (p<0.001), venous collateral scale (VCS) (p<0.001), being in the postpartum period (p=0.006), development of intracranial herniation (p<0.001), and poor clinical outcome (p<0.001) were significantly related with JH. When the significant variables were evaluated with the binary logistic regression, the most significant and independent variables were found to be SSS thrombosis (p=0.043), cortical vein thrombosis (CoVT) (p=0.010), and seizures after CVT (p=0.004). By contrast, no relationships were found between the groups in terms of VCS in binary logistic regression.Conclusion: Diagnosis of CVT is possible with high clinical suspicion and correct interpretation of radiological imaging. JH could be detected with non-contrast cranial computed tomography, which is the first imaging modality, and may cause the clinician to suspect from SSS thrombosis and CoVT. More precise results could be obtained with the prospective multicenter studies.Publication Flow diverter stents in the treatment of recanalized intracranial aneurysms(Sage Publications, 2021-01-02) Akgül, Erol; Onan, Hasan Bilen; İşlek, İrem; Tonge, Mehmet; Durmuş, Yavuz; Barbüroğlu, Mehmet; Azizova, Aynur; Erol, Cengiz; Hakyemez, Bahattin; Sencer, Serra; Aydın, Kubilay; Arat, Anıl; HAKYEMEZ, BAHATTİN; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı.; 0000-0002-3425-0740 ; AAI-2318-2021BackgroundWe assessed the safety and efficacy of flow diverter stents (FDSs) in the treatment of recanalized or residual intracranial aneurysms treated endovascularly.Materials & MethodsPatients whose recanalized or residual aneurysms were treated with FDSs in five tertiary hospitals were reviewed retrospectively. The patients' demographic data, aneurysm characteristics, types of previous treatment, and clinical complications, or serious adverse events associated with FDSs, as well as the results of neurological and angiographic follow-up assessments, were recorded.ResultsEighty-six patients (37 males) with 87 aneurysms were included in this study. Eighty (91.9%) aneurysms were in the anterior and seven (8.1%) in the posterior circulation. The initial treatment methods were the primary coiling or balloon remodeling technique in 69 (79.3%) and stent-assisted coiling in 18 (20.7%) aneurysms. The endovascular procedure was successful in all patients. Complications occurred in four patients, for a total complication rate of 4.6%. A technical complication developed in one patient (1.2%). An in-stent thrombosis treated with tirofiban was seen in two cases. Late in-stent stenosis exceeding 50% was treated with balloon angioplasty in one patient. The mean length of follow-up was 21.0 months. The first angiographic follow-up (3-6 months) revealed the complete occlusion of 74 aneurysms (85.1%). While 76 aneurysms (87.4%) were occluded at the last angiographic follow-up (mean: 26.0 months), 11 aneurysms (12.6%) were still filling. Morbimortality was zero.ConclusionThe drawback of endovascular treatment is aneurysmal remnants or recurrences, which is safely and durably amenable to flow diversion.Publication A rare cause of epilepsy: Ulegyria revisited in a series of 10 patients(Sage Publications, 2021-09-17) Demir, Aylin Bican; Eser, Pınar; Bekar, Ahmet; Hakyemez, Bahattin; Bora, İbrahim; BİCAN DEMİR, AYLİN; Eser, Pınar; BEKAR, AHMET; HAKYEMEZ, BAHATTİN; BORA, İBRAHİM HAKKI; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Nöroloji Anabilim Dalı/Epilepsi Merkezi.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Beyin Cerrahi Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı.; 0000-0001-6739-8605; 0000-0003-0132-9927; 0000-0002-3425-0740; ABX-9081-2022; AAI-2073-2021; V-7170-2017; AAI-2318-2021; ENI-7759-2022Introduction. Ulegyria results from perinatal hypoxic-ischemic brain injury in term infants. The specific mushroom-shaped configuration of ulegyria results from small atrophic circumvolutions at the bottom of a sulcus underlying an intact gyral apex. Clinically, ulegyria is generally associated with epilepsy. Here, we aimed to delineate the characteristics of patients with ulegyria and the epileptic seizures they experience. Material and methods. Medical records including radiology and pathology reports, video-electroencephalographic (EEG) analysis, operative notes, hospital progress and outpatient clinic notes were reviewed retrospectively in a total of 10 ulegyria patients. Results. Patients ages ranged between 24 and 58 years (mean, 32 +/- 9.8 years). Past medical history was confirmed for neonatal asphyxia in 2 (20%). Neurological examination was remarkable for spastic hemiparesis in 1 (10%) patient with perisylvian ulegyria and for visual field deficits in 2 patients (20%) with occipital ulegyria. Ulegyria most commonly involved the temporoparietal region (n = 5, 50%) followed by the perisylvian area (n = 2, 20%). Except the one with bilateral perisylvian ulegyria, all patients had unilateral lesions (n = 9, 90%). Hippocampal sclerosis accompanied ulegyria in 2 patients (20%). All patients experienced epileptic seizures. Mean age at seizure onset was 8.8 +/- 5.4 years (range, 2-20 years). Interictal scalp EEG and EEG-video monitoring records demonstrated temporoparietal and frontotemporal activities in 5 (50%) and 2 (20%) patients, respectively. The seizures were successfully controlled by antiepileptic medication in 8 patients (n = 8, 80%). The remaining 2 patients (%20) with concomitant hippocampal sclerosis required microsurgical resection of the seizure foci due to medically resistant seizures. Discussion. Ulegyria is easily recognized with its unique magnetic resonance imaging characteristics and clinical presentation in the majority of cases. It is highly associated with either medically resistant or medically controllable epileptic seizures. The treatment strategy depends on the age at onset and extends of the lesion that has a significant impact on the severity of the clinical picture.Publication Statistical shape analysis of putamen in early-onset Parkinson's disease(Elsevier, 2021-10) Sığırlı, Deniz; Özdemir, Senem Turan; Erer, Sevda; Şahin, İbrahim; Ercan, İlker; Özpar, Rifat; Örün, Muhammet Okay; Hakyemez, Bahattin; SIĞIRLI, DENİZ; ERER ÖZBEK, ÇİĞDEM SEVDA; ERCAN, İLKER; ÖZPAR, RİFAT; HAKYEMEZ, BAHATTİN; Özdemir, Senem Turan; Şahin, İbrahim; Bursa Uludağ Üniversitesi/Tıp Fakültesi; 0000-0001-9031-3040; 0000-0002-3425-0740; 0000-0001-6649-9287; AAA-7472-2021; FPU-9468-2022; DVY-9744-2022; HII-7787-2022; ABF-2367-2020; AAH-5062-2021; AAI-2318-2021Objective: To investigate the shape differences in the putamen of early-onset Parkinson's patients compared with healthy controls and to assess and to assess sub-regional brain abnormalities. Methods: This study was conducted using the 3-T MRI scans of 23 early-onset Parkinson's patients and age and gender matched control subjects. Landmark coordinate data obtained and Procrustes analysis was used to compare mean shapes. The relationships between the centroid sizes of the left and right putamen, and the durations of disease examined using growth curve models. Results: While there was a significant difference between the right putamen shape of control and patient groups, there was not found a significant difference in terms of left putamen. Sub-regional analyses showed that for the right putamen, the most prominent deformations were localized in the middle-posterior putamen and minimal deformations were seen in the anterior putamen. Conclusion: Although they were not as pronounced as those in the right putamen, the deformations in the left putamen mimic the deformations in the right putamen which are found mainly in the middle-posterior putamen and at a lesser extend in the anterior putamen.Publication Vertebral artery hypoplasia as an independent risk factor of posterior circulation atherosclerosis and ischemic stroke(Lippincott Williams & Wilkins, 2021-09-24) Dinç, Yasemin; Özpar, Rıfat; Emir, Büsra; Hakyemez, Bahattin; Bakar, Mustafa; DİNÇ, YASEMİN; ÖZPAR, RİFAT; HAKYEMEZ, BAHATTİN; BAKAR, HACI MUSTAFA; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Nöroloji Anabilim Dalı.; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyolog Anabilim Dalı.; 0000-0001-6649-9287; 0000-0002-3425-0740; IWC-9957-2023; AAH-5062-2021; AAI-2318-2021; EKN-8251-2022Vertebral artery hypoplasia (VAH) is a frequent anatomical variation of vertebral arteries, with emerging evidence suggesting that it contributes to posterior circulation ischemia. However, the relationship between VAH and ischemic stroke remains unknown. Hence, this study aimed to determine the prevalence of VAH in patients diagnosed with acute ischemic stroke who were followed up in a neurology clinic and to determine if it can potentially be a risk factor for atherosclerotic stenosis in vertebrobasilar circulation. This retrospective study included 609 patients diagnosed with acute ischemic stroke between January 1, 2019 and January 1, 2020. Demographic of patients, risk factors, radiological and clinical characteristics were evaluated. Posterior circulation was very common in patients with VAH, and the most common locations of atherosclerotic stenosis were V1 and V4 segments of the vertebral artery and the middle segment of basilar artery. Analysis of the risk factors for atherosclerotic stenosis in patients with posterior circulation acute ischemic stroke suggested that VAH was an independent risk factor. Findings of the study suggest that VAH pre-disposes atherosclerotic stenosis in vertebrobasilar circulation, although its mechanism remains unknown. Hemodynamic parameters associated with atherosclerosis could not be measured in vivo. Thus, to better understand the underlying mechanism, conducting studies that examine blood flow parameters with high-resolution magnetic resonance angiography in patients diagnosed with acute cerebral ischemia patients with VAH is warranted.Publication Understanding the effect of effective metal surface area of flow diverter stent's on the patient-specific intracranial aneurysm numerical model using lagrangian coherent structures(Elsevier, 2020-10-01) Mutlu, Onur; Olcay, Ali Bahadır; Bilgin, Cem; Hakyemez, Bahattin; BİLGİN, CEM; HAKYEMEZ, BAHATTİN; Bursa Uludağ Üniversitesi/Tıp Fakültesi/Radyoloji Anabilim Dalı; 0000-0002-3425-0740; AAI-2318-2021; HHS-7433-2022The effective metal surface area (EMSA) of flow diversions plays an essential role in the occlusion mechanism inside the aneurysm since the value of EMSA determines the amount of blood flow into the aneurysm sac. In the present study, three different models of a flow diverter stent, namely FRED 4017, FRED 4038, and FRED 4539, were virtually placed at the aneurysm neck of a 52-years-old female patient to identify the effect of EMSA on stagnation region formation inside the aneurysm sac. Lagrangian coherent structures (LCSs), hyperbolic time, and particle tracking analysis were employed to the velocity vectors obtained from computational fluid dynamics (CFD). It is noticed that use of FRED 4017 stent with 0.42 EMSA value caused nearly 40% of the weightless blood flow particles (more than FRED 4038 and FRED 4539) to stay inside the aneurysm while only 0.35% of the blood flow was remaining inside the aneurysm sac when no stent was placed into the aneurysm site. Furthermore, hyperbolic time computations illustrated the formation of stagnation fluid flow zones that can be associated with the residence time of the blood flow particles. Lastly, the results of hyperbolic time analysis are in good agreement with digital subtraction angiography (DSA) images taken in the clinic a few minutes after a FRED 4017 implantation. (C) 2020 Elsevier Ltd. All rights reserved.