Comparative evaluation of shear wave elastography elasticity values in thyroid nodules with cytology results and TI-RADS scoring in differentiation of benign-malignant nodules.

PURPOSE: The aim of this prospective study was to investigate the diagnostic performance of shear wave elastography (SWE) in differentiating benign and malignant thyroid nodules and their correlation with the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS). METHODS: This prospective study included 370 thyroid nodules in 308 patients aged 18-70 years. All the patients underwent B-mode ultrasound (US), Doppler examination, and SWE and were given an ACR TI-RADS risk score before fine needle aspiration biopsy (FNAB) and/or surgery. The correlation between SWE parameters and ACR TI-RADS categories was investigated statistically and compared with histopathologic results. Additionally, the diagnostic performance of SWE was evaluated to distinguish malignant and benign thyroid nodules. RESULTS: One hundred and thirty-five of the 370 thyroid nodules were malignant, and 235 nodules were benign. The mean shear wave velocity (SWV) value of the malignant nodules (3.70 ± 0.98 m/s) was statistically higher than that of the benign nodules (2.70 ± 0.37 m/s). The best cutoff value of the mean SWV for differentiating benign and malignant nodules was found to be 2.94 m/s (sensitivity 90.4%, specificity 89.9%, positive predictive value 81.3%, negative predictive value 94.1%, p < 0.001). The average score of the nodules according to the ACR TI-RADS was 3.57 ± 1.83 in benign nodules and 7.38 ± 2.69 in malignant nodules (p ≤ 0.001). CONCLUSION: This study showed that combining SWE and TI-RADS improves the specificity of TI-RADS alone in differentiating benign and malignant nodules.

Diffusion-weighted MRI at 3T in Endometrial Cancer: Correlation of Apparent Diffusion Coefficient with Histopathological Prognostic Parameters.

OBJECTIVE: To evaluate the value of apparent diffusion coefficient (ADC) for the differentiation of histological subtypes in endometrial cancer, and to assess if ADC values correlate with histopathological parameters. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Department of Radiology, Faculty of Medicine, Ondokuz Mayis University between January 2016 and December 2019. METHODOLOGY: Eighty-three patients (mean age: 60.28 ± 9.07) with endometrial cancer underwent diffusion-weighted imaging (DWI) at 3T before surgery. The mean ADC (ADCmean) and minimum ADC (ADCmin) values of the tumours were assessed to predict histological subtype of endometrial cancer, grade of tumour, presence of myometrial invasion, lower uterine segment involvement, cervical involvement, lymphovascular invasion, and lymph node metastasis. RESULTS: Sixty patients (72.3%) were diagnosed with endometrioid carcinoma, and 23 patients (27.7%) were diagnosed with non-endometrioid carcinoma. The median ADCmean/ADCmin of endometrioid and non-endometrioid tumours were 0.72/0.58 ×10-3 mm2/s and 0.82/0.63 ×10-3 mm2/s, respectively. ADCmean and ADCmin were significantly different between endometrioid and non-endometrioid tumours (p=0.016 and p=0.048). For the endometrioid carcinomas, ADCmean and ADCmin were significantly different between low-grade (G1 and G2) and high-grade (G3) tumours (ADCmean/ADCmin = 0.75/0.65 vs. 0.59/0.49 x10-3 mm2/s, p=0.010 and p=0.013). Myometrial invasion, lymphovascular invasion, cervical involvement, lower uterine involvement, serosal involvement and lymph node metastasis were not significantly associated with ADC values. CONCLUSION: ADC measurements were useful for differentiating endometrioid and non-endometrioid carcinomas. High-grade endometrioid carcinomas had significantly lower ADC values compared to low-grade ones. Key Words: Endometrial cancer, Diffusion-weighted MRI, Apparent diffusion coefficient, Prognostic factors, Histological grade.

Discrimination of papillary renal cell carcinoma from benign proteinaceous cyst based on iodine and water content on rapid kV-switching dual-energy CT.

PURPOSE: We aimed to evaluate whether rapid kV-switching dual energy CT (rsDECT) can discriminate between papillary renal cell carcinoma (RCC) and benign proteinaceous cysts (BPCs) based on iodine and water content. METHODS: Twenty-four patients with histopathologically proven papillary RCC and 38 patients with 41 BPCs were retrospectively included. Patients with BPCs were eligible for inclusion when the cysts were stable in size and appearance for at least 2 years or proved to be a cyst on ultrasound or MRI. All patients underwent delayed phase (70-90 s) rsDECT. Iodine and water content of each lesion was measured on the workstation. RESULTS: Of papillary RCC patients, 4 (16%) were female and 20 (84%) were male. Mean tumor size was 39±20 mm. Mean iodine and water content was 2.08±0.7 mg/mL and 1021±14 mg/mL, respectively. Of BPC patients, 9 were female and 29 were male. Mean cyst size was 20±7 mm. Mean iodine and water content was 0.82±0.4 mg/mL and 1012±14 mg/mL, respectively. There were significant differences between iodine and water contents of papillary RCCs and BPCs (P < 0.001). The best cutoff of iodine content for differentiating papillary RCC from BPC was 1.21 mg/mL (area under the curve [AUC]=0.97, P < 0.001, sensitivity 96%, specificity 88%, positive predictive value [PPV] 82%, negative predictive value [NPV] 97%, accuracy 91%,); the best cutoff of water content was 1015.5 mg/mL (AUC=0.68, P = 0.016, sensitivity 83%, specificity 56%, PPV 52%, NPV 85%, accuracy 66%). CONCLUSION: An iodine content threshold of 1.21 mg/mL accurately differentiates papillary RCC from BPCs on a single postcontrast rsDECT. Despite having a high sensitivity, water content has inferior diagnostic accuracy.