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Author: search.filters.author.Koc, ZaferSubject: search.filters.subject.liver

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    Diffusion-Weighted MRI and Optimal b-value For Characterization of Liver Lesions
    (2014) Kaya, Bilal; Koc, Zafer; https://orcid.org/0000-0002-8917-3375; https://orcid.org/0000-0003-0987-1980; 23982322; AAK-9366-2020; S-8384-2016
    Background: Diffusion-weighted imaging (DWI) is commonly used to distinguish between benign and malignant liver lesions. However, different b-values are recommended. Purpose: To determine the most suitable b-value in DWI for differentiation of benign and malignant liver lesions. Material and Methods: A total of 124 lesions in 89 consecutive patients (43 men, 46 women; age, mean +/- standard deviation, 58 +/- 14 years) with a pathological or radiological diagnosis of malignant or benign focal liver lesions after magnetic resonance imaging (MRI) were included in this study. Routine abdominal MRI and DWI were performed using seven b-values (0, 50, 200, 400, 600, 800, 1000 s/mm(2)). Lesions were analyzed for benignity/malignity using apparent diffusion coefficient (ADC) values with 10 b-value combinations and by measuring the lesion/normal parenchyma ADC ratio. Results: Mean ADC values were significantly different between malignant and benign lesions for all b-value combinations (P = 0.000). The best b-value combination was 0 and 800 (Az = 0.935). Using lower b-values such as 0 and 50 together with higher b-values >= 600 s/mm(2) was beneficial (Az = 0.928 and 0.927). Mean ADC values were approximately 13% (1-15%) higher in total when b = 0 and b = 50 s/mm(2) were included in multiple b-value combinations. Conclusion: In DWI, we recommend the use of b-values of 0 and 800 s/mm(2) as two b-values, or b = 0, 50, 600, 800, and 1000 s/mm(2) as multiple b-values for distinguishing between benign and malignant liver lesions. Mean ADC value is 13% higher in total by additional use of b = 0 and b = 50 s/mm(2) in multiple b-value combinations.
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    Optimal b Value in Diffusion-Weighted Imaging for Differentiation of Abdominal Lesions
    (2014) Koc, Zafer; Erbay, Gurcan; https://orcid.org/0000-0003-0987-1980; https://orcid.org/0000-0002-1706-8680; 24115207; S-8384-2016; AAK-5370-2021
    Purpose: To explore the optimal b value in diffusion-weighted imaging (DWI) for differentiation of benign and malignant abdominal lesions. Materials and Methods: A total of 108 consecutive patients (age 60 +/- 12.5 years) with 127 pathologically confirmed diagnoses of abdominal lesions were included. Single-shot echoplanar imaging (SH-EPI) DWI (1.5T) with seven b values and eight apparent diffusion coefficient (ADC) maps were obtained. The lesions were analyzed visually on DWI and ADC maps for benignity/malignity using a 5-point scale and by measuring the ADC values and ADC lesion/normal parenchyma ADC ratio. ROC analysis was used to evaluate the diagnostic accuracy of ADC for differentiating between benign and malignant lesions. Pathology results were the reference standard. Results: Differentiation between malignant and benign lesions using visual scoring was successful at b values of 600 or higher (sensitivities, specificities, and accuracies were 100/93.8/92.5, 84.7/82.6/80.4, and 94.4/89.7/88.1, respectively, for b600, 800, and 1000). The mean ADC values of malignant lesions were significantly lower than those of benign lesions for all b-value combinations except b0 and 50 s/mm(2) (P = 0.032 for b0 and 50 s/mm(2), P = 0.000 for other b values). The best b-value combination was 0 and 600 s/mm(2) and multiple b2. The lesion/normal parenchymal ADC ratio for b600, b1000, and multiple b2 better distinguished between benign and malignant lesions. Conclusion: In DWI, the optimal b value is 600 s/mm(2); multiple b values of 600 s/mm(2) and higher are recommended to differentiate between benign and malignant abdominal lesions. The lesion ADC/normal parenchyma ADC ratio is more accurate than using lesion ADC only.