J Korean Soc Radiol.  2013 Oct;69(4):269-273. 10.3348/jksr.2013.69.4.269.

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

• Shin GW
• Kim DW

• KMID: 2041945
• DOI: http://doi.org/10.3348/jksr.2013.69.4.269

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.

MeSH Terms

Humans
Neck
Preoperative Period
Sensitivity and Specificity
Thyroid Gland
Thyroidectomy

Figure

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  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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