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Öğe Advanced MRI findings in patients with breast hamartomas(Diagnostic and Interventional Radiology, 2011) Erdem, Gülnur; Karakaş, Muammer Hakkı; Işık, Burak; Fırat, 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 contrastenhanced 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 diffusionweighted 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 Bilgisayarlı tomografi ile intestinal malrotasyonun rastlantısal tanısı(Türkiye Klinikleri Journal of Medical Sciences, 2006) Fırat, Ahmet Kemal; Karakaş, Muammer Hakkı; Karaca, Salih; Sığırcı, AhmetÖğe Dynamic contrast enhanced magnetic resonance imaging findings of mass lesions of the pontocerebellar angle(Kulak Burun Boğaz İhtisas Dergisi, 2007) Fırat, Ahmet Kemal; Karakaş, Muammer Hakkı; Kahraman, Bayram; Fırat, Yezdan; Altınok, Tayfun; Kızılay, AhmetThe 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.Öğe Evaluation of in vivo cerebral metabolism on proton magnetic resonance spectroscopy in patients with impaired glucose tolerance and type 2 diabetes mellitus(J Diabetes Complications, 2008) Şahin, İbrahim; Alkan, Alpay; Keskin, Lezzan; Çıkım Sertkaya, Ayşe; Karakaş, Muammer Hakkı; Fırat, Ahmet Kemal; Sığırcı, AhmetThe 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 (A1CN10%). 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.Öğe Ultrasonographic assessment of mild and moderate idiopathic carpal tunnel syndrome(Clinical Radiology, 2004) Altınok, Tayfun; Baysal, Özlem; Karakaş, Muammer Hakkı; Sığırcı, Ahmet; Alkan, Alpay; Kayhan, Ayhan; Yoloğlu, SaimAIM: To investigate the diagnostic value of ultrasonography in mild and moderate idiopathic carpal tunnel syndrome (CTS). MATERIALS AND METHODS: Cross-sectional areas (CSA), flattening ratios at three different levels, swelling ratio, and palmar displacement were analysed in 26 patients (14 with bilateral and 12 with unilateral disease, 40 wrists in total) for the presence and the severity of CTS. Twenty had normal nerve conduction studies (NCS) defined as “mild”, and 20 of them had abnormal NCS defined as “moderate”. The control group consisted of 20 healthy participants. RESULTS: All parameters were significantly different between patient and control groups. Palmar displacement, swelling ratio, CSA at all levels and distal flattening ratio had the highest significance ðp , 0:0001Þ: The criterion with the highest sensitivity was the swelling ratio $ 1.3 (72.5%), followed by the middle CSA .9 mm2 and the palmar displacement .2.5 mm. All of these criteria had a higher sensitivity in diagnosing moderate cases (85 –100%) than diagnosing mild cases (30 –55%). There was a significant difference between normal and mild CTS groups regarding palmar displacement, distal flattening ratio, middle CSA and swelling ratio (p , 0:0001 for all) and between normal and moderate groups regarding all parameters ðp , 0:01 2 0:0001Þ: When combined middle CSA, palmar displacement and swelling ratio had an overall discriminatory accuracy of 83.8%. CONCLUSION: Additional diagnostic confirmation can be provided by ultrasonography and may be preferred as the initial step instead of electrophysiological studies. Detection of at least two of the three criteria (median nerve CSA .9 mm2 at pisiform level, swelling ratio $ 1.3, and palmar displacement .2.5 mm) may be helpful for the verification of the diagnosis.
