Thyroid volume measured by ultrasonography and CT.

Area of Science:

• Radiology
• Endocrinology
• Medical Imaging

Background:

• Accurate thyroid volume measurement is crucial for diagnosing and managing various thyroid conditions.
• Different imaging modalities, including ultrasound (US) and computed tomography (CT), are used for thyroid volume assessment.
• Standardization of measurement techniques is essential for reliable clinical interpretation.

Purpose of the Study:

• To compare the accuracy and reproducibility of two-dimensional ultrasound (US) methods and computed tomography (CT) for measuring thyroid volume.
• To evaluate the performance of US-based thyroid volume calculations in patients with and without substernal goiter extension.

Main Methods:

• Four observers performed blinded measurements of thyroid volume in 27 patients using two US techniques and CT.
• US Method 1: Calculation based on cross-sections through the gland.
• US Method 2: Calculation of each lobe as a rotation ellipsoid. CT: Calculation based on cross-sections.

Main Results:

• All three methods demonstrated fair reproducibility.
• A strong correlation (r=0.837) was observed between the two US methods.
• US (Observer 1) and CT showed a high correlation (r=0.945) in patients without substernal goiter.
• The rotation ellipsoid US method yielded smaller volumes than the cross-sectional US method.
• US measurements generally resulted in smaller thyroid volumes compared to CT.

Conclusions:

• Ultrasound measurement of thyroid volume using cross-sectional areas is a reproducible method for patients without substernal goiter.
• The US rotation ellipsoid method is less reproducible, particularly for large goiters.
• CT is the preferred imaging modality for measuring thyroid volume in goiters with substernal extension.