Figure 3 A inflammatory lesion in a 35-year-old woman. (A) Greyscale ultrasound showed that there was a solid very hypoechoic lesion in the left lobe of the thyroid, with irregular margin and a wider-than-tall shape. The nodule was C-TIRADS category 4c.(B) Contrast-enhanced ultrasound showed diffused and synchronous enhancement within the nodule at the time of the10th second after the injection of contrast agent. (C) Contrast-enhanced ultrasound showed hypo-enhancement and heterogeneity at peak (the 15th second after the injection of contrast agent), with irregular morphology. The CUES score of the lesion was −1. (D) The pathological image of the lesion, which was of subacute thyroiditis. Figure 3 was produced by PowerPoint version 2016(Microsoft corporation, WA, USA).