Does tissue harmonic imaging allow early determination of post-operative thyroid volume?

Aim: Therapy for endemic goitre after surgical resection depends on the res idual thyroid volume. Post-operative changes have been known to impair the Fundamental sonographic evaluation of residual thyroid tissue. It was our a im to determine whether THI is a feasible method for tyhroid volumetry afte r surgery. Methods: 48 patients underwent thyroidectomy, hemithyroidectomy, near total resection, or partial resection of the thyroid gland, In all pa tients THI of the neck was performed 4 (mean; range: 2-7 days) days after s urgery using an Elegra sonographic device (Siemens, Erlangen, Germany) with a transmitted frequency of 3.4 MHz and received frequency of 6.8 MHz. The examiner was blinded to the patient's diagnosis and the type of surgery. Th e residual tissue volume measured by means of THI and intraoperative volume try were both compared to sonographic volumetry 12 weeks after surgery, the latter serving as the gold standard. Accuracy of THI and intraoperative vo lumetry were tested for significant differences using a paired t-test. Resu lts: Volumetry by the surgeon was available in 26 patients (54%). The men e rror of THI volumetry was 2.4 mi (SD: 3.3 mi; maximum: 17 mi). The mean err or of intraoperative volumetry was 1.4 mi (SD: 1.9 mi; maximum: 6 mi). The mean difference between THI and intraoperative volumetry was 1 mi (SD: 2.7 mi; maximum: 7 ml; p = 0.085). Conclusions: THI permits early volumetry of the residual tissue after thyroid surgery comparable with the intraoperativ e volumetry. Thus, THI may be helpful in guiding the substitution of thyroi d hormones.