Sonographic Detection of Thyroid Pyramidal Lobes Before Thyroid Surgery

Abstract

This study aimed to assess the rate of preoperative sonographic detection of thyroid pyramidal lobes with subsequent surgical findings as the reference standard. From January 2013 to March 2013, a single radiologist prospectively performed thyroid sonography to detect thyroid pyramidal lobes in consecutive patients who were scheduled for thyroid surgery on the same day. The location, anteroposterior and transverse diameters, length, and location of the upper end of each thyroid pyramidal lobe and its separation or contiguity with the main thyroid gland were investigated by thyroid sonography and surgery. The types of thyroid surgery included total thyroidectomy (n = 85), subtotal thyroidectomy (n = 4), and hemithyroidectomy (n = 43). The surgical incidence of thyroid pyramidal lobes was 59.8% (79 of 132), and the sensitivity, specificity, positive and negative predictive values, and accuracy of sonography for detection of thyroid pyramidal lobes were 81.0%, 79.2%, 85.3%, 73.7%, and 80.3%, respectively. The mean values for the anteroposterior diameter, transverse diameter, and length of the 79 thyroid pyramidal lobes at surgery were 2.2, 6.2, and 26.5 mm, respectively, but these measurements did not show statistically significant correlations with the sonographic detection rate of thyroid pyramidal lobes. Our study indicates that thyroid sonography may be helpful for identifying the presence and location of thyroid pyramidal lobes.