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Author: search.filters.author.Karadeli, ElifSubject: search.filters.subject.magnetic resonance imaging (MRI)

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    Internal Comparison Standard for Abdominal Diffusion-Weighted Imaging
    (2017) Koc, Zafer; Erbay, Gurcan; Karadeli, Elif; 0000-0002-1706-8680; 0000-0002-0352-8818; 0000-0003-0987-1980; 27956463; AAK-5370-2021; AAK-5399-2021; S-8384-2016
    Background: Standards for abdominal diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) measurements, and analysis are required for reproducibility. Purpose: To identify optimal internal comparison standards for DWI to normalize the measured ADC for increased accuracy of differentiating malignant and benign abdominal lesions. Material and Methods: We retrospectively studied 97 lesions (89 patients; age, 57 +/- 13 years) with histopathologically confirmed abdominal disease. Seven normal body parts/contents (normal parenchyma, spleen, kidney, gallbladder bile, paraspinal muscle, spinal cord, and cerebrospinal fluid [CSF]) were assessed as internal references for possible use as comparison standards. Three observers performed ADC measurements. Statistical analyses included interclass correlation coefficients (ICCs), Mann-Whitney and Kruskal-Wallis tests, and coefficient of variation (CV). ROC analyses were performed to assess diagnostic accuracy of lesion ADC and normalized ADC for differentiating lesions. Pathology results were the reference standard. Results: Mean and normalized ADCs were significantly lower for malignant lesions than for benign lesions (P< 0.001). ICC was excellent for all internal references. Gallbladder had the lowest CV. Receiver operating characteristic (ROC) analyses showed that normalized ADCs obtained using normal parenchyma were better than lesion ADCs for differentiating malignant and benign abdominal lesions (area under the curve [AUC], 0.808 and 0.756, respectively). The normalized ADCs obtained using CSF shows higher accuracy than lesion ADCs (0.80 and 0.76, respectively) for differentiating between malignant and benign abdominal lesions. Conclusion: The normal parenchyma from a lesion-detected organ can be used as an internal comparison standard for DWI. CSF can be used as a generalizable in plane reference standard.
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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.