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PubMed2006

Measuring thyroid gland volume: should we change the correction factor?

OBJECTIVE: In the assessment of thyroid volume with sonography (formula of an ellipsoid), a correction factor is used. Whereas previously 0.524 was used, the World Health Organization has recently changed (after the first review) this correction factor to 0.479. We compare volume measurement of the thyroid using different correction factors to automated volume measurement using MDCT, and we define an optimal correction factor in thyroid volume assessment. CONCLUSION: Acceptable correction factors are situated in the range of 0.494-0.554. We propose a correction factor of 0.529 when using the ellipsoid formula.

Adult↗

PubMed2003

Reducing inter-observer variation in thyroid volume calculation using a new formula and technique.

OBJECTIVE: Ultrasound (US) measurement of thyroid volume is used in diagnosis and follow-up of patients with thyroid disease. We assessed a new formula and technique for thyroid volume calculation, based on an automatically continuous trace transverse surface area (aTSA) calculation, to ascertain where this technique could reduce inter-observer variation. METHODS: Three observers with a different level of US expertise, using a 12-5 MHz linear transducer, examined 25 volunteers. Inter-observer variations were calculated for diameter measurements and for the thyroid lobe volume calculations using the single factor ANOVA method. RESULTS: Using the new technique and formula, no statistically significant differences existed, in contradistinction to using the classical formula for an ellipsoid (P=0.02). CONCLUSION: When thyroid volume measurements are required, we recommend using a new method of thyroid volume calculation based on the use of an automatically calculated continuous trace aTSA measurement to avoid significant inter-observer variation in calculation of thyroid lobe volumes.

Adult↗