Pre-implantation assessment

Before ¹²⁵I seed implantation, all CMLNs were evaluated using conventional US combined with contrast-enhanced ultrasound (CEUS). For each CMLN, three orthogonal diameters (the largest diameter and two perpendicular diameters) were measured using US. Volume was calculated using the eq. V = πabc/6 (where V represents volume, a the largest diameter, and b and c the other two perpendicular diameters). CEUS provided visualization of the blood supply region and enhancement pattern of the lesion. The US contrast agent used was Sulphur hexafluoride (SonoVueR, Bracco. International, Milan, Italy). Bolus injection of SonoVue (2.4 ml) through the elbow vein was performed for a single CEUS and each imaging acquisition lasted for at least 3 min. Thereafter, the situated level, adjacent structures, volume and flow perfusion of each CMLN were recorded in detail. The thyroglobulin (Tg) test and routine blood analysis were also performed before implantation. Tg tests were performed at the Endocrinology Laboratory, First Medical Center, PLA General Hospital. Routine blood analysis was performed at the Laboratory Department, First Medical Center, PLA General Hospital.