Tıp Fakültesi / Faculty of Medicine

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    Predicting Tumor Recurrence in Patients with Cervical Carcinoma Treated with Definitive Chemoradiotherapy: Value Of Quantitative Histogram Analysis On Diffusion-Weighted MR Images
    (2017) Erbay, Gurcan; Onal, Cem; Karadeli, Elif; Guler, Ozan C.; Arica, Sami; Koc, Zafer; https://orcid.org/0000-0002-1706-8680; https://orcid.org/0000-0002-0352-8818; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0003-0987-1980; 27445314; AAK-5370-2021; HOC-5611-2023; AAK-5399-2021; AAC-5654-2020; S-8384-2016
    Background: Further research is required for evaluating the use of ADC histogram analysis in more advanced stages of cervical cancer treated with definitive chemoradiotherapy (CRT). Purpose: To investigate the utility of apparent diffusion coefficient (ADC) histogram derived from diffusion-weighted magnetic resonance images in cervical cancer patients treated with definitive CRT. Material and Methods: The clinical and radiological data of 50 patients with histologically proven cervical squamous cell carcinoma treated with definitive CRT were retrospectively analyzed. The impact of clinicopathological factors and ADC histogram parameters on prognostic factors and treatment outcomes was assessed. Results: The mean and median ADC values for the cohort were 1.043 +/- 0.135 x 10(-3) mm(2)/s and 1.018 x 10(-3) mm(2)/s (range, 0.787-1.443 x 10(-3) mm(2)/s). The mean ADC was significantly lower for patients with advanced stage (>= IIB) or lymph node metastasis compared with patients with stage < IIB or no lymph node metastasis. The mean ADC, 75th percentile ADC (ADC75), 90th percentile ADC (ADC90), and 95th percentile ADC (ADC95) were significantly lower in patients with tumor recurrence compared with patients without recurrence. In multivariate analysis, tumor size, ADC75 and ADC95 were independent prognostic factors for both overall survival and disease-free survival. Conclusion: ADC histogram parameters could be markers for disease recurrence and for predicting survival outcomes. ADC75, ADC90, and ADC95 of the primary tumor were significant predictors of disease recurrence in cervical cancer patients treated with definitive CRT.
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    The Role of Combined Diffusion-Weighted Imaging and Dynamic Contrast-Enhanced MRI for Differentiating Malignant From Benign Breast Lesions Presenting Washout Curve
    (2021) Tezcan, Sehnaz; Ozturk, Funda Ulu; Uslu, Nihal; Akcay, Eda Yilmaz; 32157892
    Purpose: The aim of this study is to evaluate the diagnostic performance of combined breast magnetic resonance imaging (MRI) protocol including dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in patients with enhancing lesions that demonstrated washout curve and to determine whether applying apparent diffusion coefficient (ADC) cutoff value could improve the diagnostic value of breast MRI. Methods: The retrospective study included 116 patients with 116 suspicious breast lesions, which showed washout curve on DCE-MRI, who underwent subsequent biopsy. Morphologic characteristics on DCE-MRI and ADC values on DWI were evaluated. Apparent diffusion coefficient values and morphologic features of benign and malignant lesions were compared. Diagnostic values of DCE-MRI and combined MRI, including DCE-MRI and DWI (applying an ADC cutoff value) for distinguishing malignancy from benign lesions, were calculated. Results: Of the 116 breast lesions, 79 were malignant and 37 were benign. The ADC value of malignant tumors (median ADC, 0.72 x 10(-3) mm(2)/s) was significantly lower than that of benign lesions (median ADC, 1.03 x 10(-3) mm(2)/s; P < .000). The sensitivity and specificity of an ADC cutoff value of 0.89 x 10(-3) mm(2)/s were 92% and 95%, respectively. Dynamic contrast-enhanced MRI alone presented 100% sensitivity and 59.4% specificity. Adding an ADC cutoff value of 0.89 x 10(-3) mm(2)/s provided 100% sensitivity and 81% specificity, which would have prevented biopsy for 21.6% of benign lesions without missing any malignancies. Conclusion: Applying an ADC cutoff value to DCE-MRI provides an improvement in the diagnostic value of breast MRI for differentiating among lesions presenting washout curve.