Use of Spiral Computed Tomography Volumetry for Determining the Operative Approach in Patients with Graves’ Disease

Abstract

The purposes of the present study were to assess (1) the correlation between the weight of the postoperative thyroid specimen and the spiral computed tomography (CT) volumetry results of the thyroid gland in patients with Graves' disease, and (2) the utility of CT volumetry for determining the operative approach. From 2009 to 2010, a total of 56 patients with Graves' disease underwent total or subtotal thyroidectomy. An enhanced spiral CT was taken in all patients prior to the operation. From 2.5mm-thick slices of the thyroid gland, the surface area was calculated to measure the volume of the thyroid gland. The glandular volume was compared to the weight of the postoperative thyroid specimen. A total of 42 and 14 patients underwent total and subtotal thyroidectomy, respectively. The mean weight of the postoperative thyroid specimen was 43.9±33.4g, and the mean volume obtained by CT volumetry was 44.2±32.8mL. A good correlation was observed between the weight of the postoperative thyroid specimen and the volume calculated by CT (r=0.98, p<0.001). When 100mL was set as the higher cut-off value of the thyroid volume for minimally invasive thyroid surgery, the estimated blood loss showed a significant difference between the >100mL and the ≤100mL groups (608.3±540.8 vs. 119.7±110.4mL; p=0.036). Spiral CT volumetry may be used to measure the thyroid volume reliably in patients with Graves' disease. For cases in which surgery is indicated in patients with Graves' disease, CT volumetry provides useful information from which to determine the operative approach. One hundred milliliter or less of thyroid volume in CT volumetry is recommended to perform minimally invasive thyroid surgery.