The diagnostic value of dynamic contrast-enhanced MRI for thyroid tumors

Background and purpose: The exact place for dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in the diagnosis and management of thyroid tumors is still under debate. We performed the study to analyze and compare the parameters generated from DCE-MRI for thyroid lesions. Materials and methods: For each thyroid lesion, time intensity curves (TIC), time of peak enhancement (T-peak), maximum enhancement ratio (ERmax) and maximum rise slope (Slope(max)) were plotted and calculated. Receiver operator characteristics (ROC) analysis was conducted to assess the diagnostic ability and appropriate cut-off value. The area under the ROC curve (AUC) and the confidence intervals (CIs) were also assessed. Results: Forty-two patients were consecutively included. All 21 lesions demonstrated the rapid inflow and washout pattern (type-I) were benign. The 12 cases with delayed inflow pattern (type-III) were all malignant. When compared with the benign lesions, the thyroid carcinoma showed significantly lower Slope(max) and higher T-peak (P < 0.05). No statistical difference of ERmax was found between malignant and benign ones (P = 0.15). The AUC of ERmax, Slope(max) and T-peak in differentiating benign thyroid lesions from malignant ones were 0.63, 0.93and 1, respectively. The ERmax cut-off value of 73.86 (sensitivity, 71.4%; specificity, 64.3%), Slope(max) cut-off value of 2.4126 (sensitivity, 92.9%; specificity, 82.1%) and T-peak value of 28 (sensitivity, 100%; specificity, 100%) offered the best diagnostic performances. Conclusions: DCE-MRI, especially the pattern of TIC and the value of Slope(max) and T-peak, could be helpful in differentiating thyroid carcinoma from benign thyroid lesions. (C) 2012 Elsevier Ireland Ltd. All rights reserved.