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Automatic ultrasound technique to measure angle of progression during labor
Author(s) -
Conversano F.,
Peccarisi M.,
Pisani P.,
Di Paola M.,
De Marco T.,
Franchini R.,
Greco A.,
D'Ambrogio G.,
Casciaro S.
Publication year - 2017
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 - 10.1002/uog.17441
Subject(s) - medicine , sonographer , ultrasound , symphysis , reliability (semiconductor) , reproducibility , semi automatic , algorithm , statistics , computer science , surgery , radiology , mathematics , mechanical engineering , power (physics) , physics , quantum mechanics , engineering
Objective To evaluate the accuracy and reliability of an automatic ultrasound technique for assessment of the angle of progression (AoP) during labor. Methods Thirty‐nine pregnant women in the second stage of labor, with fetus in cephalic presentation, underwent conventional labor management with additional translabial sonographic examination. AoP was measured in a total of 95 acquisition sessions, both automatically by an innovative algorithm and manually by an experienced sonographer, who was blinded to the algorithm outcome. The results obtained from the manual measurement were used as the reference against which the performance of the algorithm was assessed. In order to overcome the common difficulties encountered when visualizing by sonography the pubic symphysis, the AoP was measured by considering as the symphysis landmark its centroid rather than its distal point, thereby assuring high measurement reliability and reproducibility, while maintaining objectivity and accuracy in the evaluation of progression of labor. Results There was a strong and statistically significant correlation between AoP values measured by the algorithm and the reference values ( r = 0.99, P < 0.001). The high accuracy provided by the automatic method was also highlighted by the corresponding high values of the coefficient of determination ( r 2 = 0.98) and the low residual errors (root mean square error = 2°27′ (2.1%)). The global agreement between the two methods, assessed through Bland–Altman analysis, resulted in a negligible mean difference of 1°1′ (limits of agreement, 4°29′). Conclusions The proposed automatic algorithm is a reliable technique for measurement of the AoP. Its (relative) operator‐independence has the potential to reduce human errors and speed up ultrasound acquisition time, which should facilitate management of women during labor. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.