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 (Tpeak), maximum enhancement ratio (ERmax) and maximum rise slope (Slopemax) 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 Slopemax and higher Tpeak (P<0.05). No statistical difference of ERmax was found between malignant and benign ones (P=0.15). The AUC of ERmax, Slopemax and Tpeak in differentiating benign thyroid lesions from malignant ones were 0.63, 0.93 and 1, respectively. The ERmax cut-off value of 73.86 (sensitivity, 71.4%; specificity, 64.3%), Slopemax cut-off value of 2.4126 (sensitivity, 92.9%; specificity, 82.1%) and Tpeak value of 28 (sensitivity, 100%; specificity, 100%) offered the best diagnostic performances.

CONCLUSIONS

DCE-MRI, especially the pattern of TIC and the value of Slopemax and Tpeak, could be helpful in differentiating thyroid carcinoma from benign thyroid lesions.