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Shin and Kim: CT Detection of Thyroid Pyramidal Lobe in Preoperative Patients with Thyroid Tumors
Head and Neck Radiology

Journal of the Korean Society of Radiology 2013; 69(4): 269-273.

Published online: 7 October 2013

DOI: https://doi.org/10.3348/jksr.2013.69.4.269

CT Detection of Thyroid Pyramidal Lobe in Preoperative Patients with Thyroid Tumors

Gi Won Shin, MD, Dong Wook Kim, MD

Department of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.

Corresponding author: Dong Wook Kim, MD. Department of Radiology, Busan Paik Hospital, Inje University College of Medicine, 75 Bokji-ro, Busanjin-gu, Busan 614-735, Korea. Tel. 82-51-890-6549, Fax. 82-51-896-1085, dwultra@lycos.co.kr

Received 19 June 2013       Accepted 16 July 2013

Copyright © 2013 The Korean Society of Radiology

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose

Thyroid pyramidal lobe (TPL) is a normal variant of the thyroid gland, but few imaging studies of TPL have been published. The purpose of this study is to investigate the frequency, location, size (length, maximal AP diameter, maximal transverse diameter), and upper end level of TPL with its separation from the main thyroid gland on preoperative neck CT and to compare them with operative findings in order to assess the diagnostic accuracy of neck CT for detection TPL.

Materials and Methods

46 patients, who underwent preoperative neck CT before thyroidectomy, were included in the study. The frequency, location, size, and upper end level of TPL with its separation from the main thyroid gland on the neck CT was analyzed by a single radiologist.

Results

The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of neck CT for detecting TPL was 77.8%, 89.5%, 91.3%, 73.9% and 82.6%. There was a significant difference in maximal AP diameter, location, upper end level, and its separation from main thyroid gland between CT and operative findings (p < 0.05), but there was no significant difference in the length and maximal transverse diameter of TPL (p > 0.05).

Conclusion

Diagnostic accuracy of neck CT for detecting TPL was high, and the neck CT may be useful for evaluating TPL in the suprahyoid neck.

Keywords: Thyroid Gland, Pyramidal Lobe, Preoperative Period, Neck CT, Diagnostic Index

Figures and Tables

Fig. 1
Size measurement of thyroid pyramidal lobe in CT image on a picture archiving and communication system. Maximal anteroposterior (A) and transverse (B) diameters of thyroid pyramidal lobe are measured in axial images. The length of thyroid pyramidal lobe are determined according to the number of axial images showing thyroid pyramidal lobe.
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Fig. 2
A 52-year-old man with a right pyramidal lobe detected on neck CT and in surgery. Nonenhanced axial (A) and contrast-enhanced axial (B) CT images show the right pyramidal lobe (arrow) with the same attenuation and enhancement as the main thyroid gland (arrowheads). The right pyramidal lobe (C) is observed during thyroid surgery (arrow).
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Table 1
The Diagnostic Index of Neck CT for the Detection of Thyroid Pyramidal Lobe
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Table 2
Comparison in Size and Upper End of Pyramidal Lobe between CT and Surgical Findings in 46 Patients
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Note.-Data presented in parentheses are the percentage of each item.

*p value in each items difference between male and female.

N = number

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