Intra- and interobserver variability of thyroid volume measurements in healthy adults by 2D versus 3D ultrasound.

Full Abstract

Thyroid volume measurement by ultrasonography (US) is essential in numerous clinical diagnostic and therapeutic fields. While known to be limited, the accuracy and precision of two-dimensional (2D) US thyroid volume measurement have not been thoroughly characterized.

OBJECTIVE:
We sought to assess the intra- and interobserver variability, accuracy and precision of thyroid volume determination by conventional 2D US in healthy adults using reference volumes determined by three-dimensional (3D) US. Design,

METHODS:
In a prospective blinded trial, thyroid volumes of ten volunteers were determined repeatedly by nine experienced sonographers using conventional 2D US (ellipsoid model). The values obtained were statistically compared to the so-called true volumes determined by 3D US (multiplanar approximation), the so-called gold standard, to estimate systematic errors and relative deviations of individual observers.

RESULTS:
The standard error of measurement (SEM) for one observer and successive measurements (intraobserver variability), was 14%, and for different observers and repeated measurements (interobserver variability), 17%. The minimum relative thyroid volume change significantly different at the 95% level was 39% for the same observer and 46% for different observers. Regarding accuracy, the mean value of the differences showed a significant thyroid volume overestimation (17%, p < 0.01) by 2D relative to 3D US.

CONCLUSION:
2D US is appropriate for routine thyroid volumetry. Nevertheless, the so-called human factor (random error) should be kept in mind and correction is needed for methodical bias (systematic error). Further efforts are required to improve the accuracy and precision of 2D US thyroid volumetry by optimizing the underlying geometrical modeling or by the application of 3D US.

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Author information

Author/s: Andermann, P (P); Schlögl, S (S); Mäder, U (U); Luster, M (M); Lassmann, M (M); Reiners, Chr (C);

Affiliation: Department of Nuclear Medicine, University of Würzburg, Josef-Schneider-Strasse 2, 97080 Würzburg, Germany. andermann_p(-atsign-)klinik.uni-wuerzburg.de

Journal and publication information

Publication Type: Journal Article

Journal: Nuklearmedizin. Nuclear medicine (Nuklearmedizin), published in Germany. (Language: eng)

Reference: 2007-; vol 46 (issue 1) : pp 1-7

Dates: Created 2007/02/14; Completed 2007/04/04;

PMID: 17299648, status: MEDLINE (last retrieval date: 12/26/2008)

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adult
Female
Humans
Male
Middle Aged

Middle Aged
Observer Variation
Reference Values
Thyroid Gland - anatomy & histology; ultrasonography
Ultrasonography - methods

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