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    Association of tumor strain ratio with prognostic factors in invasive breast cancer
    (Springer, 2022) Karan, Belgin; Purbager, Ayşin
    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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    Diagnostic efficacy of posterior epidural fat interposition on magnetic resonance t1-weighted sequence in the diagnosis of spondylolysis
    (2024) Güdü, Burhan Oral; Karan, Belgin; Dilbaz, Suna
    Objective: Supportive radiologic signs may be needed to diagnose spondylolysis (SL) via lumbar magnetic resonance imaging (MRI). In SL, the slight displacement of the corpus forward and lamina posteriorly can cause the interposition of posterior epidural fat (EFI), which is normally segmental. This study aimed to determine the diagnostic value of EFI, an indirect sign of SL, on lumbar mid-sagittal T1-weighted MRI. Methods: The lumbar MRI of 115 randomly selected patients with SL and degenerative disc disease (DDD) was randomized and assessed for the presence or absence of EFI by 2 masked observers. These observers were not permitted to examine the pars region. Interobserver agreement was tested using Cohen's kappa coefficient. Results: EFI was positive in 98 (85%) of 115 patients with SL, 14 (12%) in the DDD group, and 6 (5%) with an upper vertebral level adjacent to the SL. The difference was statistically significant (P < 0.01). In patients with SL, the EFI positivity rate was highest at lumbar 5 vertebrae (94%) and lowest at lumbar 3 vertebrae (33%). The specificity, sensitivity, positive predictive value, negative predictive value, and accuracy of EFI in diagnosing SL were mean 64%, 97%, 80%, 97%, and 95%, respectively. The highest diagnostic value of EFI was at the lumbar 5 vertebrae level, where intraobserver and interobserver reliability were nearly perfect. Conclusions: EFI is an indirect radiological finding with high reliability in diagnosing SL with mid-sagittal T1-weighted images in lumbar MRI.
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    Editorial for "Differentiating benign and malignant breast lesions in diffusion kurtosis MRI: Does the averaging procedure matter?"
    (Wiley, 2022) Karan, Belgin
    Breast cancer is the most common malignant tumor inwomen. Advances in the early diagnosis and treatment ofbreast cancer in recent years have resulted in improvements inthe survival rate.1Thus, all interest and efforts in breast cancerhave been directed toward early diagnosis and treatment.
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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
    (Elsevier, 2016) Karan, Belgin; Erbay, Gürcan; Koç, Zafer; Pourbagher, Ayşin; Yıldırım, Sedat; Ağıldere, Ahmet Muhteşem
    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.