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Öğe 1H magnetic resonance spectroscopy of the normal testis(Elsevier Science Inc, 2008) Firat, Ahmet Kemal; Ugras, Murat; Karakas, Hakk M.; Erdem, Gulnur; Kurus, Meltem; Ugras, Meltem; Celik, TayfunPurpose: The purpose of this study was to determine the pre- and postpubertal H-1 magnetic resonance spectroscopic characteristics of the normal testis to establish baseline values for further clinical studies. Materials and Methods: 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. Results: 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). Conclusions: 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. (C) 2008 Published by Elsevier Inc.Öğe Advanced MRI findings in patients with breast hamartomas(Turkish Soc Radiology, 2011) Erdem, Gulnur; Karakas, Hakki Muammer; Isik, Burak; Firat, Ahmet KemalPURPOSE Although it has been stated that breast hamartomas are rare tumors, radiologists frequently encounter them in their daily practices. Fat, glandular and fibrous tissues all produce a mass of disorganized but mature specialized cells. Because hamartomas do not have specific diagnostic histological features, the clinical and radiological findings are important in their diagnosis. The aim of this study is to present the advanced magnetic resonance imaging (MRI) findings of breast hamartomas. MATERIALS AND METHODS Eight patients with breast hamartomas were examined using MRI techniques in addition to ultrasonographic and/or mammographic findings. RESULTS Each of the lesions examined showed a gradual enhancement pattern in its time-signal intensity curve on dynamic contrast-enhanced MRI. On MR spectroscopy, water and lipid peaks were detected that resembled normal breast tissue. The diffusion features of the lesions were variable due to the different ratios of the tissue elements constituting them on diffusion-weighted imaging (DWI). CONCLUSION Advanced MRI findings may clarify diagnoses by providing additional information following sonography, especially in lactating or pregnant women, in whom mammographic examination is not preferred.Öğe Bilateral Giant Benign Cystic Mesothelioma (Peritoneal Inclusion Cysts): Ultrasonography and Magnetic Resonance Imaging Findings(Galenos Yayincilik, 2007) Erdem, Gulnur; Celik, Onder; Hascalik, Seyma; Karakas, Hakki Muammer; Firat, Ahmet KemalPeritoneal inclusion cysts are most common in women of reproductive period and involve the abdomen, pelvis, and retroperitoneum. Generally these cases with a history of previous abdominal surgery present with chronic abdominal and pelvic pain. Peritoneal inclusion cysts are lined with mesothelial cells; this condition has also been referred to as benign cystic mesothelioma. In this study, we present the ultrasonographic and magnetic resonanse imaging (MRI) findings of giant benign cystic mesothelioma in 30-year-old infertil woman and the approaches of the treatment mentioned in literature. On ultrasonography and MRI, peritoneal inclusion cysts are seen as abdominopelvic multiloculated cystic masses. In that case, peritoneal inclusion cysts should be added into the differential diagnosis list in the cases with a history of previous abdominal surgery.Öğe Diffusion-Weighted Images Differentiate Benign From Malignant Thyroid Nodules(Wiley, 2010) Erdem, Gulnur; Erdem, Tamer; Karakas, Hakki Muammer; Mutlu, Deniz Yakar; Firat, Ahmet Kemal; Sahin, Ibrahim; Alkan, AlpayPurpose: To reveal the possible role of diffusion-weighted images (DWI) in the differential diagnosis of benign and malignant thyroid nodules by comparing the results of fine-needle aspiration cytology (FNAC). Materials and Methods: In an 18-month period (December 2005 to May 2007), 27 cases with benign thyroid nodules with a total of 52 benign nodules, nine cases with thyroid gland malignancy and 24 healthy control cases were included in the study. Cases that were indicated to undergo to FNAC examination and sent by a clinician for biopsy to the radiology unit were included in the study to assess the cytopathologic confirmation of the clime, ultrasonographic, and magnetic resonance imaging (MRI) findings. Results: The mean apparent diffusion coefficient (ADC) values of thyroid nodules were 2745.3 +/- 601.1 x 10(-6) mm(2)/s (1605-3899 x 10(-6)mm(2)/s) in the benign group and 695.2 +/- 312.5 x 10(-6)mm(2)/s (165-1330 x 10(-6)mm(2)/s) in the malignant group. Normal thyroid tissues had mean ADC values of 1344.1 +/- 276.4 x 10(-6) mm(2)/s (1015-1764 x 10(-6)mm(2)/s). The ADC values of three subgroups were significantly different (P = 0.0001). A reduced ADC was observed in most. types of malignant tumors due to the consequent decrease of the extracellular extravascular space. Conclusion: Our preliminary results showed that ADC values of nodules may provide useful data about the nature of a thyroid nodule.Öğe Diffusion-weighted imaging evaluation of subtle cerebral micro structural changes in intrauterine fetal hydrocephalus(Elsevier Science Inc, 2007) Erdem, Gulnur; Celik, Onder; Hascalik, Seyma; Karakas, Hakki Muammer; Alkan, Alpay; Firat, Ahmet KemalObjective: 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. Materials and Methods: 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/mm(2)). 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. 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). Conclusion: 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. (c) 2007 Elsevier Inc. All rights reserved.Öğe A Heart Transplant Recipient Lost Due to Pneumocystis jiroveci Pneumonia Under Trimethoprim-Sulfamethoxazole Prophylaxis: Case Report(Baskent Univ, 2010) Celik, Tuncay; Gedik, Ender; Kayabas, Uner; Bayindir, Yasar; Gulbas, Gazi; Firat, Ahmet Kemal; Togal, TurkanInfections 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.Öğe Incontinentia pigmenti: a case report and literature review(Turkish J Pediatrics, 2009) Emre, Sinan; Firat, Yezdan; Gungor, Serdal; Firat, Ahmet Kemal; Karincaoglu, YeldaIncontinentia 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.Öğe Interpedicular Approach in Percutaneous Sacroplasty for Treatment of Sacral Vertebral Body Pathologic Fractures(Springer, 2011) Firat, Ahmet Kemal; Gumus, Burcak; Kaya, Emin; Kuku, Irfan; Harma, AhmetFor this technique, bone needle is introduced into the S1 vertebral body through the interpedicular route by penetrating the central spinal canal at the level of S3-4 and passing through the vertebral body of S2-3 parallel to the anterior border of sacrum. With the interpedicular approach, two sacral vertebral bodies can be injected in one session and lower sacral body injection also is available. interpedicular technique is a safe, practical, and effective technique for the treatment of sacral vertebral body pathologic fractures.Öğe Isolated preauricular pits and tags: is it necessary to investigate renal abnormalities and hearing impairment?(Springer, 2008) Firat, Yezdan; Sireci, Sule; Yakinci, Cengiz; Akarcay, Mustafa; Karakas, Hakki Muammer; Firat, Ahmet Kemal; Kizilay, AhmetWe investigated the incidence and co-existence of hearing impairment and renal abnormalities in healthy children with preauricular tags and pits. Study population consists of 13,740 primary school children from routine health check. Thirty-five children with preauricular tags and pits were noted. Control group consisted of 91 patients without pits and tags, who underwent renal ultrasound and were scheduled to pediatric outpatient clinic. Urinanalysis, renal ultrasound, otoacoustic emission were performed in both the groups. The prevalence of renal abnormality (1/36; 2.7%) and hearing impairment (1/36; 2.7%) in patients with preauricular tags and pits was similar to that of control group (3/91; 3.2% and 4/91; 4.3%) (P = 0.87, P = 0.64, respectively). According to our results, it is not necessary to investigate hearing or urinary abnormality in patients with preauricular tag or pit, unless there is an association of a syndrome or family history of hearing or renal impairment.Öğe Magnetic resonance spectroscopy features of normal-appearing white matter in patients with acute brucellosis(Elsevier Ireland Ltd, 2008) Kayabas, Uner; Alkan, Alpay; Firat, Ahmet Kemal; Karakas, Hakki Muammer; Bayindir, Yasar; Yetkin, FundaWe 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. (C) 2007 Elsevier Ireland Ltd. All rights reserved.Öğe Microstructural Changes in Uterine Leiomyomas and Myometrium: A Diffusion-Weighted Magnetic Resonance Imaging Study(Karger, 2009) Erdem, Gulnur; Celik, Onder; Karakas, Hakki Muammer; Hascalik, Seyma; Firat, Ahmet KemalAlthough 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. Copyright (C) 2009 S. Karger AG, BaselÖğe Neuroimaging findings in hyperargininemia(Wiley-Blackwell, 2008) Gungor, Serdal; Akinci, Aysehan; Firat, Ahmet Kemal; Tabel, Yilmaz; Alkan, AlpayIn 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.Öğe SUBAREOLAR BREAST ABSCESS: ADVANCED MAGNETIC RESONANCE IMAGING FINDINGS(Aves, 2008) Erdem, Gulnur; Isik, Burak; Karakas, Hakki Muammer; Firat, Ahmet KemalBreast abscesses are generally seen in women in lactation period and located in the retroareolar and periareolar areas. Occasionally, subareolar abscesses may occur in young and middle aged women in non-lactation. Advanced imaging techniques may be needed to discriminate inflammatory breast carcinomas from subareolar abscesses with high risk of recurrence. We detected multipl breast abscesses in 26 year-old woman in non-lactation period and presented the findings of dynamic magnetic resonance imaging, diffusion-weighted imaging and magnetic resonance spectroscopy in addition to the findings of ultrasonography and conventional magnetic resonance imaging. Although the diagnosis of breast lesions depends basically on clinical findings, mammography and sonography findings, the usefulness of advanced magnetic resonance imaging techniques has been reported increasingly in differential diagnosis. This imaging techniques provide additional information to mammography and ultrasonography by bringing about non-invasive approaches.
