Browsing by Author "Karan, Belgin"

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    Association of Tumor Strain Ratio with Prognostic Factors in Invasive Breast Cancer
    (2022) Karan, Belgin; Purbager, Aysin; https://orcid.org/0000-0002-7034-7806
    We evaluate the correlations between tumor strain ratio value and prognostic factors for breast cancers. Fifty-seven women with invasive breast cancer underwent ultrasound elastography prior to surgery. Elastography strain ratio (SR), defined as the fat-to-lesion ratio, was recorded for each lesion using the software in the ultrasound equipment. We evaluated the associations between tumor SR and pathological prognostic factors such as tumor subtype, tumor size, axillary lymph node metastasis, histological grade, vascular invasion, and hormonal receptor status. We found a significant correlation between tumor SR and progesterone receptor (PR) status (p = 0.02). Tumors with axillary lymph node metastasis had a higher SR value than those without lymph node metastasis; however, this difference was not significant. Strain elastography revealed that grade 3 tumors had softer tissues than grade 1 and 2 tumors, although this was not statistically significant. The tumor SR value was not significantly correlated with tumor subtypes, tumor size, vascular invasion, and estrogen receptor or cell surface human epidermal growth factor 2 status (p > 0.05). The present study demonstrated no significant correlation between SR values and prognostic factors, except for PR status. However, tumors with LN metastasis tended to exhibit greater stiffness, and higher grade tumors exhibited lower stiffness owing to necrosis. Further studies with large study population on tumor-associated stiffness are required.
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    Utility of Diffusion-Weighted MRI to Detect Changes in Liver Diffusion in Benign and Malignant Distal Bile Duct Obstruction: The Influence of Choice of b-Values
    (2016) Karan, Belgin; Erbay, Gurcan; Koc, Zafer; Pourbagher, Aysin; Yildirim, Sedat; Agildere, Ahmet Muhtesem; 0000-0003-0987-1980; 0000-0002-5735-4315; 0000-0002-1706-8680; 0000-0003-4223-7017; 27592163; S-8384-2016; AAF-4610-2019; AAK-5370-2021; AAB-5802-2020
    Purpose: The study sought to evaluate the potential of diffusion-weighted magnetic resonance imaging to detect changes in liver diffusion in benign and malignant distal bile duct obstruction and to investigate the effect of the choice of b-values on apparent diffusion coefficient (ADC). Methods: Diffusion-weighted imaging was acquired with b-values of 200, 600, 800, and 1000 s/mm(2). ADC values were obtained in 4 segments of the liver. The mean ADC values of 16 patients with malignant distal bile duct obstruction, 14 patients with benign distal bile duct obstruction, and a control group of 16 healthy patients were compared. Results: Mean ADC values for 4 liver segments were lower in the malignant obstruction group than in the benign obstruction and control groups using b = 200 s/mm(2) (P < .05). Mean ADC values of the left lobe medial and lateral segments were lower in the malignant obstruction group than in the benign obstructive and control groups using b = 600 s/mm2 (P < .05). Mean ADC values of the right lobe posterior segment were lower in the malignant and benign obstruction groups than in the control group using b = 1000 s/mm(2) (P < .05). Using b = 800 s/mm(2), ADC values of all 4 liver segments in each group were not significantly different (P > .05). There were no correlations between the ADC values of liver segments and liver function tests. Conclusion: Measurement of ADC shows good potential for detecting changes in liver diffusion in patients with distal bile duct obstruction. Calculated ADC values were affected by the choice of b-values.