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Observational Study
. 2024 Jun;63(6):772-780.
doi: 10.1002/uog.27541.

Accuracy of portable ultrasound machines for obstetric biometry

K J Rittenhouse  1 , B Vwalika  1   2 , Y Sebastião  1 , T Pokaprakarn  3 , N Sindano  4 , H Shah  5 , E M Stringer  1 , M P Kasaro  2   4 , S R Cole  6 , J S A Stringer  1   4 , J T Price  1   4
Affiliations
Observational Study

Accuracy of portable ultrasound machines for obstetric biometry

K J Rittenhouse et al. Ultrasound Obstet Gynecol. 2024 Jun.

Abstract

Objective: To evaluate the accuracy of two portable ultrasound machines (PUM) in assessing fetal biometry and estimated gestational age (EGA).

Methods: This was a secondary analysis of data from the Fetal Age Machine Learning Initiative, an observational study of pregnant women in the USA and Zambia. Each participant underwent ultrasound assessment by an experienced sonographer using both a high-specification ultrasound machine (HSUM) and a PUM (Butterfly iQ or Clarius C3) to measure fetal biometry and calculate EGA at each visit. By comparing paired PUM and HSUM scans, we estimated agreement between individual biometry measurements and aggregate gestational age estimates by reporting mean difference, intraclass correlation coefficient (ICC) and Bland-Altman plots, adjusting for trend.

Results: Between April and December 2021, 818 participants contributed 1386 paired PUM-HSUM ultrasound investigations, of which 991 PUM scans were obtained using the Butterfly iQ device and 395 using the Clarius C3 device. Gestational age at scan ranged from 7 to 38 weeks. Compared with HSUM, the Butterfly iQ PUM had a mean difference of -0.20 (95% CI, -0.60 to 0.20) days in the first trimester and -0.68 (95% CI, -0.93 to -0.44) days in the second/third trimesters. Compared with HSUM, the Clarius C3 PUM had a mean difference of -0.47 (95% CI, -1.11 to 0.18) days in the first trimester and -1.67 (95% CI, -2.10 to -1.25) days in the second/third trimesters. ICCs were 0.989 or greater throughout. Increasing gestational age was associated with increasing error and absolute error in EGA and fetal biometry. Both PUM devices demonstrated a modest trend toward underestimation of EGA with advancing gestational age in second/third-trimester scans, compared with HSUM.

Conclusion: The Butterfly iQ and Clarius C3 PUM devices were highly accurate in performing fetal biometry in a diverse population from the USA and Zambia. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Keywords: access to care; fetal biometry; obstetric ultrasound; point‐of‐care ultrasound; portable ultrasound; validation study.

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Figures

Figure 1:
Figure 1:
Study Sampling and Inclusion Approach.
Figure 2:
Figure 2:
First and Second/Third Trimester PUM vs. HSUM EGA. Scatterplots (a,c,e,g) of PUM vs HSUM EGA calculations with linear regression (red dashed line) and perfect fit plot (black line). Bland-Altman Plots (b,d,f,h) including linear predicted mean difference (black dashed line) and LOA (gray shaded region). Difference modeled as PUM minus HSUM. PUM: portable ultrasound machine; HSUM: high-specification ultrasound machine; EGA: estimated gestational age; LOA: limits of agreement
See this image and copyright information in PMC

References

    1. Yadav H, Shah D, Sayed S, Horton S, Schroeder LF. Availability of essential diagnostics in ten low-income and middle-income countries: results from national health facility surveys. Lancet Glob Health 2021. Nov;9(11):e1553–60. - PMC - PubMed
    1. Van Dyk B, Motto JA, Buchmann EJ. Routine second-trimester ultrasound for low risk pregnancies in a South African community. Int J Obstet Gynecol 2007. Sep;98(3):257–8. - PubMed
    1. Geerts LTGM Brand EJ, Theron GB. Routine obstetric ultrasound examinations in South Africa: cost and effect on perinatal outcome-a prospective randomised controlled trial. BJOG 1996. Jun;103(6):501–7. - PubMed
    1. Rykkje Carlsen, Nielsen. Hand-held ultrasound devices compared with high-end ultrasound systems: a systematic review. Diagnostics 2019. Jun 15;9(2):61. - PMC - PubMed
    1. Del Medico M, Altieri A, Carnevale-Maffè G, Formagnana P, Casella F, Barchiesi M, Bergonzi M, Vattiato C, Casazza G, Cogliati C. Pocket-size ultrasound device in cholelithiasis: diagnostic accuracy and efficacy of short-term training. Intern Emerg Med 2018. Oct;13(7):1121–6. - PubMed

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