Person: ALKAN, ALPAY
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Publication Open Access MRI and MR Spectroscopy Features of Heat Stroke: A Case Report(2018-07-01) Yilmaz, TEMEL FATİH; Aralasmak, AYŞE; Toprak, HÜSEYİN; GULER, Serhat; Tüzün, Umit; Alkan, ALPAY; YILMAZ, TEMEL FATİH; ARALAŞMAK, AYŞE; TOPRAK, HÜSEYİN; ALKAN, ALPAYHeat stroke is the outcome of over heat stress that results in multiorgan dysfunction with a tendency for central nervous system damage. Brain is very sensitive to hyperthermia, especially the cerebellum that has selective vulnerability to heat stroke. There is complex interaction between heat cytotoxicity, coagulation disorder, cytotoxine - mediated systemic inflammatory response causing multiorgan failure, metabolic derangement, and circulatory insufficiency. We reviewed the literature and discussed brain MRI and MR spectroscopy findings of heat stroke, detailed the pathophysiology underlying brain involvement and proposed excitotoxic injury as an alternative mechanism of brain damage in heat stroke.Publication Open Access The Effect of Obesity on Brain Diffusion Alteration in Patients with Obstructive Sleep Apnea(2014-01-01) KILICARSLAN, Rukiye; Alkan, ALPAY; Sharifov, RASUL; Akkoyunlu, MUHAMMED EMİN; Aralasmak, AYŞE; KOCER, Abdulkadir; KART, Levent; ALKAN, ALPAY; SHARIFOV, RASUL; AKKOYUNLU, MUHAMMED EMİN; ARALAŞMAK, AYŞEPurpose: We investigated diffusion alterations in specific regions of the brain in morbid obese, obese, and nonobese OSA patients and searched whether there is a correlation between BMI and ADC values. Materials and methods: DWIs of 65 patients with OSA were evaluated. The patients were classified according to BMI as morbid obese (n = 16), obese (n = 27), and nonobese (control, n = 22) groups. ADC measurements were performed from 24 different regions of the brain in each patient. The relationship of BMI with ADC values was searched. Results: The ADC values in hypothalamus, insular cortex, parietal cortex, caudate nucleus, frontal white matter, and posterior limb of internal capsule were all increased in obese patients (n = 43) compared to control group. The ADC values of midbrain, hypothalamus, orbitofrontal cortex, and parietal cortex were significantly increased in morbid obese compared to obese patients. In obese patients, the degree of BMI was positively correlated with ADC values of orbitofrontal cortex, parietal cortex, and hypothalamus. Conclusion: We observed increasing brain vasogenic edema with increasing BMI, suggesting that the main reason of brain diffusion alteration in patients with OSA could be obesity related.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 Relationship of white matter hyperintensities with clinical features of seizures in patients with epilepsy(2021-11-19T00:00:00Z) Uslu, Ferda Ilgen; Çetintaş, Elif; Alkan, ALPAY; Kolukisa, Mehmet; USLU, FERDA; YURTSEVER, İSMAİL; ALKAN, ALPAYBackground: Although epilepsy is primarily known as a cortical disorder, there is growing body of research demonstrating white matter alterations in patients with epilepsy. Objective: To investigate the prevalence of white matter hyperintensities (WMH) and its association with seizure characteristics in patients with epilepsy. Methods: The prevalence of WMH in 94 patients with epilepsy and 41 healthy controls were compared. Within the patient sample, the relationship between the presence of WMH and type of epilepsy, frequency of seizures, duration of disease and the number of antiepileptic medications were investigated. Results: The mean age and sex were not different between patients and healthy controls (p>0.2). WMH was present in 27.7% of patients and in 14.6% of healthy controls. Diagnosis of epilepsy was independently associated with the presence of WMH (ß=3.09, 95%CI 1.06-9.0, p=0.039). Patients with focal epilepsy had higher prevalence of WMH (35.5%) than patients with generalized epilepsy (14.7%). The presence of WMH was associated with older age but not with seizure characteristics. Conclusions: WMH is more common in patients with focal epilepsy than healthy controls. The presence of WMH is associated with older age, but not with seizure characteristics.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 Brain Diffusion Changes in Obstructive Sleep Apnoea Syndrome(2013-01-01) Akkoyunlu, MUHAMMED EMİN; Kart, Levent; KILICARSLAN, Rukiye; Bayram, MEHMET; Aralasmak, AYŞE; Sharifov, RASUL; Alkan, ALPAY; AKKOYUNLU, MUHAMMED EMİN; BAYRAM, MEHMET; ARALAŞMAK, AYŞE; SHARIFOV, RASUL; ALKAN, ALPAYBackground: Obstructive sleep apnoea syndrome (OSAS) is a disorder characterized by repeated apnoeic episodes during sleep. Neurocognitive changes secondary to OSAS are likely to occur due to hypoxia in certain brain locations. Advances in magnetic resonance imaging technology, such as diffusion-weighted imaging (DWI), enable non-invasive and accurate identification of OSAS-induced changes. Objective: We aimed to use DWI to investigate changes in the brain secondary to hypoxia in OSAS. Methods: Eighty-eight patients underwent polysomnography and were classified as non-OSAS, mild-moderate OSAS and severe OSAS sufferers. DWI was used to evaluate 14 areas of the brain, and apparent diffusion coefficients (ADCs) were calculated. We investigated whether there were differences in the ADC values in specific areas of the brain between the non-OSAS and OSAS patients. Results: We measured the ADC values of the 68 newly diagnosed OSAS patients (21 mild, 15 moderate and 32 severe) and of 20 healthy controls. There were significant increases in the ADC values in the hippocampus, amygdala and putamen in OSAS patients. Compared to thenon-OSAS subjects, the ADC values of the putamen in severe OSAS patients, those of the hippocampus in moderate or severe OSAS patients and those of the amygdala in moderate OSAS patients were significantly increased. A negative correlation between the lowest oxygen saturation during sleep and the ADC values of the hippocampus and amygdala was found. Conclusions: Increased ADC levels in the hippocampus, amygdala and putamen in OSAS patients indicate hypoxia and likely cause vasogenic oedema in specific regions of the brain.Publication Open Access Brain Perfusion MRI Findings in Patients with Behcet-s Disease(2012-01-01T00:00:00Z) Alkan, ALPAY; GOKTAN, Asli; Karincaoglu, Yelda; KAMIŞLI, SUAT; Dogan, Metin; Oztanir, Namik; Turan, Nergiz; KOCAKOC, Ercan; ALKAN, ALPAY; ÖZTANIR, MUSTAFA NAMIKObjective. To search brain perfusion MRI (pMRI) changes in Behcet-s disease (BD) with or without neurological involvement. Materials and Method. The pMRI were performed in 34 patients with BD and 16 healthy controls. Based on neurologic examination and post-contrast MRI, 12 patients were classified as Neuro-Behcet (group 1, NBD) and 22 patients as BD without neurological involvement (group 2). Mean transit time (MTT), time to peak (TTP), relative cerebral blood volume (rCBV), and relative cerebral blood flow (rCBF) were obtained and compared to those of healthy control group (group 3). Results. There was a significant difference in the MTT and rCBF within the pons and parietal cortex in groups 1 and 2. rCBV increased in cerebral pedicle in group 1 compared with groups 2 and 3. In the temporal lobe white matter, prolonged MTT and decreased rCBF were found in groups 1 and 2. In the corpus striatum, internal capsule, and periventricular white matter, rCBF increased in group 1 compared with group 3 and decreased in groups 1 and 2. Conclusion. Brain pMRI is a very sensitive method to detect brain involvement in patients with BD and aids the clinical diagnosis of NBD, especially in patients with negative MRI findings.Publication Open Access Severe Posterior Reversible Encephalopathy in Pheochromocytoma: Importance of Susceptibility-Weighted MRI(2013-09-01) SERTER, Asli; Alkan, ALPAY; Aralasmak, AYŞE; KOCAKOC, Ercan; ALKAN, ALPAY; ARALAŞMAK, AYŞEPheochromocytoma is a rare cause of hypertension in children. Hypertension is one of the common reasons of posterior reversible encephalopathy. Intracerebral hemorrhage is a serious and unexpected complication of hypertensive encephalopathy due to pheochromocytoma, and very rarely seen in the childhood. Intracerebral hemorrhages should be searched if there are hypertensive reversible signal changes on the brain. Susceptibility weighted imaging (SWI) is a more sensitive method than conventional MRI when demonstrating cerebral microhemorrhagic foci. This is the first report of SWI findings on intracerebral hemorrhages in basal ganglia, brain stem and periventricular white matter due to hypertensive encephalopathy in a child with pheochromocytoma.Publication Open Access Clinical and molecular findings in 6 Turkish cases with Krabbe disease(2022-01-01T00:00:00Z) Aslanger, Ayça Dilruba; Şengenç, Esma; Kölemen, Ayşe Betül; Demiral, Emine; Alkan, ALPAY; İşcan, Akın; Yeşil, Gözde; ALKAN, ALPAYBackground. Krabbe disease is a rare lysosomal storage disorder with a neurodegenerative course that occurs because of the deficiency of the beta-galactocerebrosidase (GALC) enzyme activity. The genetic basis of Krabbe disease consists of biallelic mutations in the GALC gene, but the genetic spectrum in the Turkish population is poorly defined. We aimed to present a Turkish case-series with infantile-onset Krabbe disease, define the clinical and molecular findings and compare the genetic spectrum with the mutations previously reported in the literature. Methods. Six cases, who were referred to our clinic between 2015-2019, with a definite diagnosis of infantileonset Krabbe disease were included in the study. The family history, clinical information, biochemical and radiological examinations of the patients were screened and evaluated. All encoded exons and exon-intron regions of the GALC gene were sequenced using next generation sequencing technology. Multiplex ligationdependent probe amplification analysis was used for deletion type mutations that could not be detected by sequence analysis. Results. GALC gene sequence analysis revealed four known mutations including c.1394C>T (p.Thr465Ile), c.411_413delTAA (p.Lys139del), c.820G>C (p.Glu274Gln), and 30 kilobase deletion mutation among the exons 11-17 (IVS10del30kbp). Moreover, the c.1623G>A (p.Trp541Ter) variant, which was not previously reported in the literature, was detected in two cases. Conclusions. We believe that the demonstration of the genetic spectrum of infantile-onset Krabbe disease in Turkish patients will be an important contribution to the GALC mutation data in our country. More importantly, two novel variants were defined. This knowledge may enable early detection and treatment with the advent of a carrier or newborn screening tests.