Ultrasonographic contrast agent: evaluation of time-intensity curves in the characterisation of solitary thyroid nodules.

Time-intensity curves, and particularly wash-out curves, provide useful information for the characterisation of solitary thyroid nodules. 93% of benign nodules (with regular vascularization) showed a monophasic pattern of the wash-out curve, while 89% of malignant nodules ("anarchical" vascularization) had polyphasic wash-out curves. This behaviour was observed in both hypervascularized and hypovascularized lesions. Our method proved to have a sensitivity of 88% and a specificity of 93%. The study of time-intensity curves could therefore enable us to differentiate between benign and malignant lesions and characterise hypovascularized malignant nodules which would not be observed without contrast agent.