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Intra‐ and interoperator repeatability of the nuchal translucency measurement
Author(s) -
Pajkrt E.,
Mol B.W.J.,
Boer K.,
Drogtrop A.P.,
Bossuyt P.M.M.,
Bilardo C.M.
Publication year - 2000
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1046/j.1469-0705.2000.00088.x
Subject(s) - repeatability , medicine , intraclass correlation , nuchal translucency , nuchal translucency measurement , operator (biology) , confidence interval , standard deviation , nuclear medicine , reproducibility , limits of agreement , coefficient of variation , kappa , statistics , mathematics , first trimester , gestation , pregnancy , biochemistry , chemistry , geometry , repressor , biology , gene , transcription factor , genetics
Objective The aim of this study was to assess the repeatability of nuchal translucency measurement by well‐trained sonographers either experienced or inexperienced with the measurement. Methods The nuchal translucency was measured three times by two out of nine operators in 161 pregnant women attending two teaching hospitals. Intra‐operator and inter‐operator variation was assessed by calculating the standard deviation (SD). Intraclass Correlation Coefficients (ICC) with a 95% lower confidence limit (95% CL) were calculated for each operator and for pairs of operators. Intra‐and inter‐operator kappa statistics were calculated, after dichotomising the results into a nuchal translucency smaller or larger than 3 mm. Results The SD of intra‐operator difference was 0.35 mm. The intra‐operator repeatability showed ICCs varying from 0.83 to 0.95 for the experienced operators and from 0.47 to 0.83 for the inexperienced. The SD of inter‐operator differences was 0.56 mm, 0.46 mm and 0.44 mm, based on one, two and three measurements, respectively. The inter‐operator repeatability showed a variation in ICC from 0.74 to 0.95 in pairs of experienced sonographers to 0.51 in one pair inexperienced with the measurement. The kappa value expressing the intra and inter‐operator repeatability as being > 3 mm or < 3 mm was 0.88 and 0.85, respectively. Conclusion This study supports the finding that the nuchal translucency measurement is reproducible, as long as it is performed by sonographers well trained in the technique of this measurement. Copyright © 2000 International Society of Ultrasound in Obstetrics and Gynecology