Ahmet Kemal Firat

Inonu University, Malatia, Malatya, Turkey

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Publications (35)62.55 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Cutaneous anthrax, caused by Bacillus anthracis contacting the skin, is the most common form of human anthrax. Recent studies implicate the presence of additional, possibly toxin-related subtle changes, even in patients without neurological or radiological findings. In this study, the presence of subtle changes in cutaneous anthrax was investigated at the metabolite level using magnetic resonance spectroscopy. Study subjects were consisted of 10 patients with cutaneous anthrax without co-morbid disease and/or neurological findings, and 13 healthy controls. There were no statistical differences in age and gender between two groups. The diagnosis of cutaneous anthrax was based on medical history, presence of a typical cutaneous lesion, large gram positive bacilli on gram staining and/or positive culture for B. anthracis from cutaneous samples. Brain magnetic resonance imaging examination consisted of conventional imaging and single-voxel magnetic resonance spectroscopy. Magnetic resonance spectroscopy was performed by using point-resolved spectroscopy sequence (TR: 2000ms, TE: 136ms, 128 averages). Voxels of 20mm×20mm×20mm were placed in normal-appearing parietal white matter to detect metabolite levels. Cerebral metabolite peaks were measured in normal appearing parietal white matter. N-acetyl aspartate/creatine and choline/creatine ratios were calculated using standard analytical procedures. Patients and controls were not statistically different regarding parietal white matter N-acetyl aspartate/creatine ratios (p=0.902), a finding that implicates the conservation of neuronal and axonal integrity and neuronal functions. However, choline/creatine ratios were significantly higher in patient groups (p=0.001), a finding implicating an increased membrane turnover. In conclusion, these two findings point to a possibly anthrax toxins-related subtle inflammatory reaction of the central nervous system at the cellular level.
    Medical Hypotheses 04/2012; 79(1):43-6. · 1.18 Impact Factor
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    ABSTRACT: Infections in solid-organ transplant recipients are the most important causes of morbidity and mortality. A primary goal in organ transplant is the prevention or effective treatment of infection, which is the most common life-threatening complication of long-term immunosuppressive therapy. A 21-year-old woman who underwent heart transplant 3 years previous owing to dilated cardiomyopathy was referred to our hospital with symptoms of high fever and cough. The patient's history revealed that she had received a trimethoprim-sulfamethoxazole double-strength tablet each day for prophylactic purposes. On chest radiograph, pneumonia was detected, and in broncho-alveolar lavage sample, Pneumocystis jiroveci cysts were found. After diagnosing P. jiroveci pneumonia, trimethoprim-sulfamethoxazole was initiated at 20 mg/kg/d including intravenous trimethoprim in divided dosages every 6 hours. On the sixth day of therapy, she died in intensive care unit. In solid-organ transplant recipients, although antipneumocystis prophylaxis is recommended within the first 6 to 12 months after transplant, lifelong prophylaxis is also used in several settings. In addition, the physician should keep in mind that P. jiroveci pneumonia may develop in solid organ recipients, despite trimethoprim-sulfamethoxazole prophylaxis.
    Experimental and clinical transplantation : official journal of the Middle East Society for Organ Transplantation. 12/2010; 8(4):325-8.
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    ABSTRACT: Although morphological and histopathological changes in uterine leiomyomas have been investigated in detail, the microstructural disruptions could not be studied in the living organism. Diffusion-weighted magnetic resonance imaging (DWI) is a novel tool to assess microstructural changes in vivo. The aim of this study was to investigate and characterize the diffusional property of leiomyomatous tissues with DWI. Sixteen females with a total of 21 leiomyomas were imaged with a 1.5-tesla clinical MR scanner. DWI images of leiomyomas, adjacent myometrial and myometrial tissues of healthy controls were obtained and quantified using apparent diffusion coefficient (ADC) maps. Mean ADC values of these groups were 1,201, 1,684, 1,661 mm(2)/s x 10(-6), respectively. ADC values in leiomyomas were significantly lower than those observed in the myometrium (p < 0.001). Cut-off values produced 91% sensitivity and 100% specificity. As ADC values implied the presence of cytotoxic edema in leiomyomas, the technique was found to be promising in observing temporal variations in leiomyomas and to monitor even the most subtle effects of therapeutic interventions.
    Gynecologic and Obstetric Investigation 01/2009; 67(4):217-22. · 1.10 Impact Factor
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    ABSTRACT: Incontinentia pigmenti (IP) is a rare, X-linked dominant disorder that presents at or soon after birth with characteristic cutaneous signs. The eyes and central nervous system are the next most commonly affected systems. We aimed to describe the ophthalmological, neurological and radiodiagnostic findings of a patient with IP and bilateral retinal detachment. Clinical and laboratory findings of a four-month-old female baby who did not have light fixation and had neurological maturation retardation are presented. Characteristic skin lesions of IP were noted especially at the extremities, bilaterally. On neurological examination, motor and mental maturation were retarded and axial hypotonia was noted. Bilateral retinal detachment was the cause of absent eye fixation noted during ophthalmologic examination, and the detachments were also documented by ultrasonography and magnetic resonance imaging (MRI). Otologic examination was normal. Focal left frontal lobe atrophy, corpus callosum hypoplasia and prominence of right hemisphere were also noted on MRI. MR spectroscopy revealed negative lactate peak at the involved left frontal lobe. Bilateral retinal detachment is a probable finding in IP and patients with neurological symptoms should be investigated for associated sight-threatening ocular pathologies.
    The Turkish journal of pediatrics 01/2009; 51(2):190-4. · 0.56 Impact Factor
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    ABSTRACT: We aimed to evaluate whether the subtle metabolic cerebral changes are present in normal-appearing white matter on conventional MRI, in patients with acute brucellosis, by using MR spectroscopy (MRS). Sixteen patients with acute brucellosis and 13 healthy control subjects were investigated with conventional MRI and single-voxel MRS. Voxels were placed in normal-appearing parietal white matter (NAPWM). N-Acetyl aspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios were calculated. There was no significant difference between the study subjects and the control group in NAA/Cr ratios obtained from NAPWM. However, the Cho/Cr ratios were significantly higher in patients with acute brucellosis compared to controls (p=0.01). MRS revealed metabolic changes in normal-appearing white matter of patients with brucellosis. Brucellosis may cause subtle cerebral alterations, which may only be discernible with MRS. Increased Cho/Cr ratio possibly represents an initial phase of inflammation and/or demyelination process of brucellosis.
    European Journal of Radiology 04/2008; 65(3):417-20. · 2.51 Impact Factor
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    ABSTRACT: In hyperarginenemia, there is a defect in argininase enzyme, which is a catalyzer of urea cycle. Though the pathogenesis of neuronal damage in hyperargininemia is not clear, high serum and cerebrospinal fluid arginine levels can be directly related with neuronal damage. In this study, our aim was to assess brain magnetic resonance images and magnetic resonance spectroscopy (MRS) patterns of two siblings with hyperarginenemia. We acquired single voxel MRS from the white matter to show the myelination pattern and to figure out any abnormal peak of metabolite stored due to enzymatic defect. We observed mild cerebral and cerebellar atrophy and infarct at bilateral posterior putamen and insular cortex localization on conventional images and elevated choline/creatine ratios and abnormal peak at 3.8 ppm, most likely representing arginine deposition. To the best of our knowledge, this is the first article revealing the brain MRS pattern of hyperargininemia. We reported the clinical and imaging findings of patients and discuss the correlation.
    Journal of neuroimaging: official journal of the American Society of Neuroimaging 02/2008; 18(4):457-62. · 3.36 Impact Factor
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    B Alicioglu, H M Karakas, A K Firat
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    ABSTRACT: A case of 5 year old juvenile patient with dermatomyositis together with conventional and diffusion-weighted MRI images is reported. The reported case was atypical for the pattern of involvement of the accompanying oedema which was affecting distal parts of the extremities and anterior muscle groups. Electromyography was negative. The case confirmed by a pathologist demonstrates the use of diffusion weighted imaging in determining unequivocal oedema and its exact extent.
    Prague medical report 02/2008; 109(4):315-20.
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    ABSTRACT: The purpose of this study was to determine the pre- and postpubertal 1H magnetic resonance spectroscopic characteristics of the normal testis to establish baseline values for further clinical studies. The subjects consisted of male volunteers, of whom 19 were prepubertal with ages between 7 and 13 years and 24 were postpubertal with ages between 19 and 39 years. Their testes were evaluated at 1.5 T with magnetic resonance spectroscopy; in addition, testis volumes were measured. Major metabolite peaks were identified and their ratios were calculated. Metabolite differences of testis between pre- and postpubertal age were analyzed. Major constituents of spectra were 3.21 ppm choline and 0.9-1.3 ppm lipid peaks. At the echo time (TE) spectrum of 31 ms, choline/lipid ratios ranged from 0.35 to 8.30 (mean=1.87) in postpubertal males and from 0.06 to 5.45 (mean=0.88) in prepubertal males (P<.013). At the TE spectrum of 136 ms, choline/lipid ratios ranged from 0.66 to 15.42 (mean=4.09) in postpubertal males and from 0.05 to 4.91 (mean=0.9) in prepubertal males (P<.016). Choline/lipid ratio was higher in the postpubertal period. The existence of higher choline peak in that age group should be due to the initiation of spermatogenesis. The decrease in the lipid peak may represent the effect of testosterone on testicular tissue or may be due to histochemical changes initiated by puberty. The significant decrease in choline/lipid ratio noted after puberty could represent the presence of spermatogenesis. This hypothesis should be evaluated by further studies on postpubertal subjects with impaired spermatogenesis.
    Magnetic Resonance Imaging 02/2008; 26(2):215-20. · 2.06 Impact Factor
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    ABSTRACT: Tendon disorders are rare events associated with fluoroquinolone congestion. Skin reactions are more frequent than tendon disorders. We reported this case as the combination of ciprofloxacin-induced urticaria and tenosynovitis has been unreported in young women. A 28-year-old woman without underlying disease developed urticarias and tendinopathy 4 days after the initiation of ciprofloxacin treatment for urinary infection. MRI of the left foot revealed increased synovial fluid surrounding the tendon of the flexor hallucis longus muscle representing tenosynovitis. Ciprofloxacin was ceased due to the possibility of ciprofloxacin-induced tendinopathy and urticaria. Complete resolution of her symptoms and findings occurred 3 days after discontinuation of ciprofloxacin without any additional treatment. Early discontinuation of fluoroquinolone therapy when tendinopathy is suspected is the basis of therapy. So, it should be kept in mind that fluoroquinolone-induced tendinopathy may occur in an otherwise healthy young patient with no risk factors and in a site other than the Achilles tendon.
    Chemotherapy 02/2008; 54(4):288-90. · 2.07 Impact Factor
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    ABSTRACT: The aim of this study was to investigate possible metabolic alterations in cerebral tissues on magnetic resonance spectroscopy (MRS) in patients with impaired glucose tolerance (IGT) and with type 2 diabetes mellitus (T2-DM). Twenty-five patients with T2-DM, 13 patients with IGT, and 14 healthy volunteers were included. Single-voxel spectroscopy (TR: 2000 ms, TE: 31 ms) was performed in all subjects. Voxels were placed in the frontal cortex, thalamus, and parietal white matter. N-acetylaspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and myo-inositol (MI)/Cr ratios were calculated. Frontal cortical Cho/Cr ratios were increased in patients with IGT compared to control subjects. Parietal white matter Cho/Cr ratios were significantly higher in patients with IGT when compared to patients with T2-DM. In the diabetic group, frontal cortical MI/Cr ratios were increased, and parietal white matter Cho/Cr ratios were decreased when compared to the control group. Frontal cortical NAA/Cr and Cho/Cr ratios and parietal white matter Cho/Cr ratios were decreased in diabetic patients with poor glycemic control (A1C>10%). A1C levels were inversely correlated with frontal cortical NAA/Cr and Cho/Cr ratios and with parietal white matter Cho/Cr ratios. T2-DM and IGT may cause subtle cerebral metabolic changes, and these changes may be shown with MRS. Increased Cho/Cr ratios may suggest dynamic change in membrane turnover in patients with IGT. Diabetic patients with poor glycemic control may be associated with neuronal dysfunction/damage in brain in accordance with A1C levels and, in some, extend with insulin resistance.
    Journal of diabetes and its complications 01/2008; 22(4):254-60. · 2.11 Impact Factor
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    ABSTRACT: Hydrocephalus is an important etiological factor in neurological decline. With the advent of fetal ultrasound, fetal hydrocephalus is now more frequently detected than in the past. Ultrasonography (USG) provides information on general morphology, but microstructural changes that may play a prognostic role are beyond the resolution of that technique. These changes may theoretically be revealed by diffusion-weighted magnetic resonance imaging (DW-MRI). In this study, our preliminary findings of DW-MRI on the hydrocephalic fetuses are presented. Twelve fetuses with fetal USG diagnosis of hydrocephalus were investigated using a 1.5-T MR scanner. In addition to conventional techniques, DWI was performed. It was obtained using a single-shot echo-planar imaging sequence (TR/TE: 4393/81 ms; slice thickness: 5 mm; interslice gap: 1 mm; FOV: 230 mm; matrix size: 128x256; b values: 0 and 1000 s/mm2). Apparent diffusion coefficient (ADC) values were measured in the white matter of the periventricular frontal and occipital lobes, basal ganglia, thalamus, centrum semiovale and cerebrospinal fluid in the lateral ventricle. These values were compared with the normal prenatal ADC values from a radiological study published in the literature. All fetuses had moderate or severe bilateral supratentorial ventricular dilatation that was compatible with hydrocephalus. On conventional T1- and T2-weighted imaging, cerebral parenchyma had normal signal pattern and ADC values were significantly lower than those reported for fetuses with normal brain. These values were lower in hydrocephalic fetuses with statistical significance (P<.05-.01). DWI is a sensitive technique to investigate cerebral microstructure. The reduction in cerebral blood flow and alterations in cerebral energy metabolism in cases with hydrocephalus have been shown before. Changes in cerebral blood flow and energy metabolism, as a consequence of cerebral compression, may occur in hydrocephalus. Elevated ventricular pressure may cause cerebral ischemia. The anaerobic glycolysis seen in the hydrocephalic brain tissue by increasing the lactate concentration and intracellular fluid flux may be the reason for the reduced ADC values in hydrocephalic fetuses. However, long-term prospective trials on the correlation of ADC values and neurological outcome are necessary to exploit the full benefit of that novel technique.
    Magnetic Resonance Imaging 12/2007; 25(10):1417-22. · 2.06 Impact Factor
  • Pediatrics International 09/2007; 49(4):519-21. · 0.88 Impact Factor
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    ABSTRACT: The differential diagnosis of mass lesions of the pontocerebellar angle is not always possible by conventional magnetic resonance imaging (MRI). In this study, we investigated the role of dynamic contrast-enhanced MRI in the differential diagnosis of acoustic neurinoma, meningioma, and paraganglioma. Twelve patients (8 females, 4 males; mean age 47.5 years; range 8 to 71 years) whose diagnoses were acoustic neurinoma (n=3), paraganglioma (n=5), and meningioma (n=4) were evaluated by simultaneous conventional and dynamic contrast-enhanced MRI. Prior to postcontrast T1-weighted images, dynamic MRI was obtained. On these images, maximum contrast enhancement (Cmax) and time to peak enhancement (Tmax) were calculated at 15 different time points. Time-signal intensity curve patterns of the lesions were compared. According to the four main time-signal intensity curve patterns described in the literature, acoustic neurinomas, meningiomas, and paragangliomas exhibited type C, type A-B, and type A curve patterns, respectively. Our results suggest that dynamic contrast MRI may have an additional but limited role in the differential diagnosis of extra-axial intracranial tumors such as those of the pontocerebellar angle.
    Kulak burun bogaz ihtisas dergisi: KBB = Journal of ear, nose, and throat 02/2007; 17(4):217-23.
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    ABSTRACT: Postradiotherapy necrosis in the larynx is a rare but serious complication. It must be differentiated from tumor recurrence with radiological and histopathological studies. Herein, we presented two patients with stage II and stage IV larynx carcinoma who developed chondroradionecrosis following radiotherapy. The first patient did not accept surgical treatment and was treated with curative radiotherapy at a dose of 70 Gy. The other one received adjuvant radiotherapy at a dose of 46 Gy following total laryngectomy and bilateral functional neck dissection. The two patients were evaluated with computed tomography and magnetic resonance imaging, respectively. Pathologic examination of multiple biopsies taken from both cases showed coagulation necrosis without malignancy. The first patient had grade IV radionecrosis according to the Chandler classification and underwent total laryngectomy because of non-functional larynx. Histopathologically, there were no malignant cells, but widespread fibrosis and coagulation necrosis. The other patient was treated with conservative treatment and local debridement.
    Kulak burun bogaz ihtisas dergisi: KBB = Journal of ear, nose, and throat 02/2007; 17(4):242-8.
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    Y Firat, A K Firat, H M Karakaş, C Onal
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    ABSTRACT: Sinonasal ossifying fibroma is a rare, slow-growing, benign bony tumour, frequently involving the maxilla and mandible in the head and neck region. Although it is known to be the second most frequent fibro-osseous tumour of paranasal sinus, to the best of our knowledge, ossifying fibroma of frontal sinus causing brain abscess has not been presented yet in the relevant literature. We present the clinical, pathological and radiological findings of ossifying fibroma of the frontal sinus associated with brain abscess.
    Dentomaxillofacial Radiology 12/2006; 35(6):447-50. · 1.27 Impact Factor
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    ABSTRACT: Magnetic resonance spectroscopy (MRS) of a 12-year-old female patient with glutaric aciduria type II was compared with data obtained from four healthy age- and sex-matched volunteers. In the clinically active phase, conventional magnetic resonance imaging showed mild ventricular dilatation. Frontal lobe choline/creatine (Cho/Cr) ratio (1.98) was higher than the ratios reported for the comparison participants (1.64 [SD 0.21]). The N-acetylaspartate/creatine (NAA/Cr) ratio (1.95) was lower than normal limits (2.66 [SD 0.23]). After successful riboflavin treatment and dietary restriction for proteins, the NAA/Cr ratio was within the normal range (2.44) and Cho/Cr ratio was below the normal range (1.15), suggesting riboflavin-responsive multiple acyl-coA dehydrogenase deficiency. An elevated Cho/Cr ratio and decreased NAA/Cr ratio is consistent with a demyelinating process in the active phase of glutaric aciduria type II. MRS helps to monitor the progress of the disease and the efficacy of treatment by revealing changes in NAA/Cr and Cho/Cr ratios.
    Developmental Medicine & Child Neurology 11/2006; 48(10):847-50. · 2.68 Impact Factor
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    ABSTRACT: A female aged 12 months with developmental delay and left-sided reverse ocular bobbing (rapid deviation of the eye upward and a slow return to the horizontal position) was observed. At birth, an upper left gingival mass, pathologically diagnosed as a benign granular cell tumour, was removed. On computed tomography (CT), left middle cerebral pedincular and midpontine lesions were seen. Magnetic resonance imaging revealed additional white matter hamartomas, corticosubcortical tubers, and subependymal nodules. The patient was re-examined at 36 months. Her general developmental quotient was equivalent to 23 months of age. Third cranial nerve functions and auditory brainstem response were normal. Her abnormal eye movements were still present. Reverse bobbing is usually observed in patients who are unconscious and who have significant pontine pathology and disruption of the reticular formation. This case is the first tuberous sclerosis-related ocular bobbing case to our knowledge and is interesting as the causative lesion was relatively mild, and ocular horizontal movements were preserved.
    Developmental Medicine & Child Neurology 11/2006; 48(10):851-4. · 2.68 Impact Factor
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    ABSTRACT: Detection of early phase neurological deficit in babies with hypoxic-ischemic encephalopathy (HIE) is the most important step to determine the appropriate preventive treatment methods. Diffusion-weighted imaging (DWI) is the most sensitive radiological modality to detect ischemic changes in the brain, in their earliest phase. Herein, we present the results of our study about the role of DWI in the diagnosis and determining the prognosis of HIE in neonates. The study included 36 cases (4 preterm, 32 term babies) who were diagnosed with HIE within 24 hours of birth and classified according to modified Sarnat staging. They were examined for the presence of neurological sequelae at 3 and 6 months of age with electroencephalography (EEG), visual evoked potential (VEP), brainstem auditory evoked potential (BAEP), and Denver II developmental screening tests. All 36 patients underwent conventional magnetic resonance (MR) imaging and DWI within the first 24 hours of birth; survivors underwent repetitive imaging exams at the end of the first week and then after a month. Seventeen stage I cases (47%), 12 stage II cases (33%), and 7 stage III cases (20%) were detected. DWI obtained within the first 24 hours showed high sensitivity (100%) in detecting the permanent neurological sequelae but with very low specificity (20%). The negative predictive value of DWI in this period was 100%; however, in DWI obtained at the end of the first month, not only its sensitivity was preserved, but its specificity reached 80%. The negative predictive value of DWI in this period was preserved and the positive predictive value improved. The importance of DWI in detecting sequelae at the end of the first month was also demonstrated by McNemar (p=0.250) and Kappa (Kappa=0.719) tests. There was no difference between conventional MR imaging and DWI in detecting sequelae at the end of first month. DWI is superior to other imaging modalities in detecting ischemia; not only because of its high sensitivity in the early phase, but also because of its high sensitivity and specificity in the late phase. Moreover, with its high negative predictive value, DWI can be used for excluding the possibility of sequelae development in the early phase of HIE cases for medico-legal purposes.
    Diagnostic and interventional radiology (Ankara, Turkey) 10/2006; 12(3):109-14. · 1.03 Impact Factor
  • Anadolu kardiyoloji dergisi: AKD = the Anatolian journal of cardiology 10/2006; 6(3):302-3. · 0.72 Impact Factor
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    ABSTRACT: Brucellosis is an endemic disease seen in many countries. It may affect different organ systems. Brucellar breast abscess is a rare entity. We report the radiological findings of breast abscess due to brucella. A 63-year-old female was investigated with mammography, ultrasonography, magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS). A mass measuring 25 x 20 x 15 mm was detected in the left breast on mammography and ultrasonography. The mass was homogenously hyperintense on T1- and T2-weighted MRI images. On contrast-enhanced T1-weighted images, peripheral capsular enhancement was found. MR spectroscopic analysis of the mass revealed elevated lipid and acetate peaks. The diagnosis was provided by fine needle aspiration biopsy and specimen culture. The lesion had diminished in size after 12 months' treatment with combined tetracycline and rifampicine.
    The Breast 09/2006; 15(4):554-7. · 2.49 Impact Factor

Publication Stats

127 Citations
62.55 Total Impact Points

Institutions

  • 2004–2009
    • Inonu University
      • Department of Radiology
      Malatia, Malatya, Turkey
  • 2008
    • Trakya University
      • Department of Radiology
      Adrianoupolis, Edirne, Turkey
  • 2006
    • Hacettepe University
      • Department of Radiology
      Ankara, Ankara, Turkey
  • 2005
    • University of Texas Southwestern Medical Center
      • Department of Radiology
      Dallas, TX, United States