Thyroid volumetric quantification: comparative evaluation between conventional and volumetric ultrasonography.
OBJECTIVE
Thyroid volume quantification is an important parameter for radiotherapy dosing in cases of major thyroid diseases such as thyroiditis and carcinoma. In clinical practice, this calculation is performed by means of ultrasonography on the basis of an ellipsoid formula obtained from the 3 axes. The aim of our study was to compare the accuracy of volume calculation between B-mode ultrasonography and volumetric ultrasonography (VUS).


METHODS
Between April and May 2007, 27 consecutive patients selected for thyroidectomy were prospectively evaluated. One expert ultrasound operator calculated each thyroid volume with standard B-mode ultrasonography on the basis of the 3 axes of each lobe, and then the patients were analyzed with an offline workstation equipped with volumetric probes (VUS). On the offline workstation, 2 separate blinded operators (VUS1 and VUS2) calculated the thyroid volume with virtual organ computer-aided analysis. Data acquired were then compared with pathologic anatomy (PA).


RESULTS
The mean time for B-mode analysis was 6 minutes, whereas VUS analysis needed a mean time of 16.5 minutes. Interobserver variability between the median VUS1 and VUS2 measurements was 0.36 mL (interquartile range [IQR], -0.79 to 0.37 mL; P < .156). The median variability between B-mode ultrasonography and PA was -9.6 mL (IQR, -16.7 to 1.5 mL; P < .001), and that between VUS and PA was -2.87 mL (IQR, -11.97 to 9.51 mL; P = .019). The overall performance of B-mode ultrasonography in comparison with PA was -29.1% (IQR, -47.5% to -5.9%), and that of VUS in comparison with PA was -6.3% (IQR, -26.3 to 13.7%; P < .001).


CONCLUSIONS
Volumetric ultrasonography is a valid tool that compares better with PA than does B-mode ultrasonography.
Malago
Roberto
R
Department of Radiology, Policlinico G. B. Rossi, University of Verona, Verona, Italy. rmalag@sirm.org
D'Onofrio
Mirko
M
Ferdeghini
Marco
M
Mantovani
William
W
Colato
Chiara
C
Brazzarola
Paolo
P
Motton
Massimiliano
M
Mucelli
Roberto Pozzi
RP
D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013959:Thyroid Diseases / Q000000981:diagnostic imaging*; D013961:Thyroid Gland / Q000000981:diagnostic imaging*; D014463:Ultrasonography / Q000379:methods*