Clinical and economic impact of incidental thyroid lesions found with CT and MR

PURPOSE: To estimate the prevalence and the clinical and economic consequences of management strategies for thyroid lesions detected incidentally on cross-sectional imaging of the head and neck. METHODS: Two hundred consecutive CT scans and 200 consecutive MR images of the neck performed over a 1-year period in patients being examined for other purposes were reviewed retrospectively to determine the prevalence of unexpected thyroid lesions. After excluding patients with prior thyroidectomies, known thyroid disease, and inadequate examinations, 231 imaging studies were analyzed. RESULTS: Incidental thyroid lesions were originally reported in 14 (6%) of the 231 patients, but an additional 22 (9.5%) were found on retrospective review for a total of nearly 16% (36 of 231). Six of the 36 patients received further workup, consisting of nuclear medicine scintigraphy (n = 3), sonography (n = 3), thyroid function tests (n = 5), fine-needle aspiration (n = 4), and thyroid lobectomy (n = 1). Final diagnoses, obtained in four of the six patients, included three multinodular goiters and one follicular adenoma. Two patients, one with nondiagnostic findings at fine- needle aspiration and a second with normal thyroid function test results, are being followed up. The mean cost of the workup and treatment per examined patient was $1158. CONCLUSION: Incidental thyroid lesions are frequently present and often overlooked on cross-sectional images of the neck in patients being examined for other reasons. The cost of pursuing a workup of these lesions and their high prevalence in the population raise questions regarding appropriate management strategies.