The prevalence and features of thyroid pyramidal lobe, accessory thyroid, and ectopic thyroid as assessed by computed tomography: a multicenter study.

Background and Purpose: Understanding the computed tomography (CT) characteristics of the pyramidal lobe and other thyroid variations and detecting them accurately using preoperative neck CT will minimize unnecessary remnant thyroid tissue after total thyroidectomy in patients with thyroid cancer. The purpose of the present study was to assess the frequency, location, and size of the pyramidal lobe and other thyroid variations using a large-scaled, multicenter study. Methods: Neck CT scans for 200 patients were selected from 11 institutions; a total of 2200 patients were included in the study. The patients underwent neck CT for the following reasons: trauma, known thyroid malignancy, cervical lymphadenopathy, palpable neck mass, oropharyngolaryngeal malignancy, vocal cord palsy, postchemotherapy CT follow-up, inflammatory or infectious neck lesion, parathyroid abnormality, and patient request. A single radiologist at each institution retrospectively analyzed 200 neck CT scans. Each radiologist investigate...