Yazar "Basak, Muzaffer" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    CAN MAGNETIC RESONANCE SPECTROSCOPY ADEQUATELY DIFFERENTIATE NEOPLASTIC FROM NON-NEOPLASTIC AND LOW-GRADE FROM HIGH-GRADE LESIONS IN BRAIN MASSES?
    (Marmara Univ, Fac Medicine, 2010) Karatag, Ozan; Karatag, Gulden Yenice; Uysal, Ender; Can, S. Meltem; Erturk, Mehmet; Basak, Muzaffer
    Objective: The aim of this study was to evaluate the usefulness of Magnetic Resonance Spectroscopy in the differential diagnosis of brain lesions. Materials and Methods: Forty-six patients with cerebral lesions were examined by Magnetic Resonance Spectroscopy. Choline, creatine, N-acetyl aspartate and lipid-lactate peaks were evaluated. Forty of the 46 patients underwent stereotactic biopsy or surgery. Histopathological results were compared with the Magnetic Resonance Spectroscopy results. Results: The Choline / N-acetyl aspartate ratio had the highest sensitivity (87.2%) in neoplastic versus nonneoplastic differentiation and the specificities of the Choline / Creatine, Choline / N-acetyl aspartate and Choline+Creatine / N-acetyl aspartate ratios were found to be 100%. Choline / Creatine ratios showed the highest sensitivity (95.7%) in low-grade versus high-grade differentiation and specificities of Choline / N-acetyl aspartate, Choline+Creatine / N-acetyl aspartate ratios and lipid-lactate levels were found to be 100%. Consequently, a value of Choline / Creatine > 2.2 and an accompanying lipid-lactate peak differentiated neoplasms as low-grade versus high-grade with a sensitivity of 100% (82.2-100%) and a specificity of 100% (71.7-100%). Conclusion: The presence of elevated Choline and decreased N-acetyl aspartate levels are effective in the differetiation of neoplastic versus non-neoplastic lesions with high sensitivity and specificity. A proposed ratio of Choline / Creatine > 2.2 and an accompanying lipid-lactate peak provide valuable information in differentiating low-grade from high-grade lesions.
  • [ X ]
    Öğe
    Diffusion Weighted MRI for Hepatic Fibrosis: Impact of b-Value
    (Kowsar Publ, 2014) Ozkurt, Huseyin; Keskiner, Firat; Karatag, Ozan; Alkim, Canan; Erturk, Sukru Mehmet; Basak, Muzaffer
    Background: Hepatic fibrosis is a typical complication of chronic liver diseases resulting in cirrhosis that remains a major public health problem worldwide. Liver biopsy is currently the gold standard for diagnosing and staging hepatic fibrosis. Percutaneous liver biopsy; however, is an invasive procedure with risks of complications. Therefore, there is need for alternative non-invasive techniques to assess liver fibrosis and chronic liver diseases. In recent years, MRI techniques, including diffusion weighted imaging (DWI), have been developed for in vivo quantification of liver fibrosis. Objectives: The purpose of this study is to evaluate the utility of diffusion weighted MRI in the diagnosis and quantification of the degree of hepatic fibrosis and to investigate the influence of b-value. Patients and Methods: Twenty-four patients (13 males, 11 females), with a mean age of 46 years (36-73 years) diagnosed as chronic hepatitis and histopathologically proven liver fibrosis and 22 other patients (8 males, 14 females) with no clinical or biochemical findings of liver disease, with a mean age of 51.2 years (32-75 years) were included in the study. All patients with chronic hepatitis underwent percutaneous liver biopsy by an experienced hepatologist without sonographic guidance. The Knodell histology activity index (HAI) for grading of necroinflammatory changes and Metavir scoring system for staging of the liver fibrosis were used to record the severity of the disease. All patients were examined with a 1.5 Tesla MRI system and the patients underwent diffusion weighted imaging (DWI) with a routine hepatic MRI protocol. Different b-values including 250, 500, 750, and 1000 sec/mm(2) were used to calculate apparent diffusion coefficients. Results: We detected decreased apparent diffusion coefficient values in patients with hepatic fibrosis compared to patients without chronic hepatitis and there was a trend toward decrease in hepatic apparent diffusion coefficient values with an increasing degree of fibrosis. Conclusions: Our findings suggest that hepatic apparent diffusion coefficient measurement with a b-value of 750 sec/mm(2) or greater is useful in accurate quantification of liver fibrosis and necroinflammation.
  • [ X ]
    Öğe
    The ability of phased-array MRI in preoperative staging of primary rectal cancer: correlation with histopathological results
    (Turkish Soc Radiology, 2012) Karatag, Ozan; Karatag, Gulden Yenice; Ozkurt, Huseyin; Degirmenci, Hulya Kurtul; Avlanmis, Omer; Basak, Muzaffer; Baykan, Adil
    PURPOSE This study evaluated the accuracy of phased-array magnetic resonance imaging (MRI) for preoperative local tumor staging in primary rectal cancer and emphasized the importance of the preoperative differentiation of T2 tumors from T3 tumors so the appropriate treatment can be applied. MATERIALS AND METHODS Twenty-four patients with primary rectal cancer were examined preoperatively using 1.5 T MRI with a phased-array coil. Multiplanar T2-weighted images were obtained. Rectum anatomy, depth of tumor invasion, mesorectal involvement and lymph nodes were assessed. All patients underwent radical surgery. The histological sections were evaluated microscopically. The correlation of magnetic resonance imaging and histopathology was assessed using the kappa statistic. Overstaging with MRI was compared with Fischer's exact test. RESULTS Histopathological examination of the tumors revealed adenocarcinoma. When the tumors were staged, there was one patient with a pT1 tumor, six patients with pT2 tumors, and 17 patients with pT3 tumors. Using MRI, four patients with pT2 were overstaged as T3, and one patient with pT3 was overstaged as T4. In the remaining cases (one pT1, two pT2, and 16 pT3), MRI correctly assessed the stage of transmural invasion. The accuracy of T staging and metastatic lymph node detection with MRI was calculated as 79.2% and 58.5%, respectively. CONCLUSION Phased-array MRI is a valuable technique for the preoperative staging of rectal cancer, especially in the differentiation of T2 and T3 tumors.