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. 2019 Feb 27;34(9):e68.
doi: 10.3346/jkms.2019.34.e68. eCollection 2019 Mar 11.

Addition of Cervical Elastography May Increase Preterm Delivery Prediction Performance in Pregnant Women with Short Cervix: a Prospective Study

Hyun Soo Park  1 , Hayan Kwon  1 , Dong Wook Kwak  2   3 , Moon Young Kim  2 , Hyun-Joo Seol  4 , Joon-Seok Hong  5 , Jae-Yoon Shim  6 , Sae-Kyung Choi  7 , Han-Sung Hwang  8 , Min Jeong Oh  9 , Geum Joon Cho  9 , Kunwoo Kim  10 , Soo-Young Oh  11 ; Korean Society of Ultrasound in Obstetrics and Gynecology Research Group
Affiliations

Addition of Cervical Elastography May Increase Preterm Delivery Prediction Performance in Pregnant Women with Short Cervix: a Prospective Study

Hyun Soo Park et al. J Korean Med Sci. .

Abstract

Background: We investigated whether there is a difference in elastographic parameters between pregnancies with and without spontaneous preterm delivery (sPTD) in women with a short cervix (≤ 25 mm), and examined the ability of elastographic parameters to predict sPTD in those women.

Methods: E-CervixTM (WS80A; Samsung Medison, Seoul, Korea) elastography was used to examine the cervical strain. Elastographic parameters were compared between pregnancies with and without sPTD. Diagnostic performance of elastographic parameters to predict sPTD ≤ 37 weeks, both alone and in combination with other parameters, was compared with that of cervical length (CL) using area under receiver operating characteristic curve (AUC) analysis.

Results: A total of 130 women were included. Median gestational age (GA) at examination was 24.4 weeks (interquartile range, 21.4-28.9), and the prevalence of sPTD was 20.0% (26/130). Both the elastographic parameters and CL did not show statistical difference between those with and without sPTD. However, when only patients with CL ≥ 1.5 cm (n = 110) were included in the analysis, there was a significant difference between two groups in elasticity contrast index (ECI) within 0.5/1.0/1.5 cm from the cervical canal (P < 0.05) which is one of elastographic parameters generated by E-Cervix. When AUC analysis was performed in women with CL ≥ 1.5 cm, the combination of parameters (CL + pre-pregnancy body mass index + GA at exam + ECI within 0.5/1.0/1.5 cm) showed a significantly higher AUC than CL alone (P < 0.05).

Conclusion: An addition of cervical elastography may improve the ability to predict sPTD in women with a short CL between 1.5 and 2.5 cm.

Keywords: Elastography; Pregnancy; Preterm Delivery; Short Cervix; Strain; Ultrasonography.

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Conflict of interest statement

Disclosure: The authors have no potential conflicts of interest to disclose.

Figures

Fig. 1
Fig. 1. Measurements and ROI definitions in elastography images. (A) CL measurement using 6-MHz transvaginal probe in B-mode ultrasonography. Measurement areas of E-Cervix. (B) Strain values of the IOS and EOS are measured using a 1-cm radius from IOS, and EOS, respectively. (C) Values of strain mean, hardness ratio, and ECI are measured from within 0.5/1.0/1.5 cm area of the cervical canal. The patient agreed to publication of the elastography image of the uterine cervix.
ROI = regions of interest, CL = cervical length, IOS = internal os of cervix, EOS = external os of cervix, ECI = elasticity contrast index.
Fig. 2
Fig. 2. E-Cervix elastography image generation processes. (A) Flow diagram of E-Cervix elastography measurements. (B) E-Cervix elastography image generation by multiple frames.
Fig. 3
Fig. 3. Receiver operating characteristic curve using the predicted probability calculated from the logistic regression model using CL, pre-pregnancy BMI, GA at CL measurement, and parameters of ECI within 1.5 cm from the cervical canal.
AUC = area under receiver operating characteristic curve, BMI = body mass index, CL = cervical length, GA at CL = gestational age at cervical length measurement, ECI = elasticity contrast index.
See this image and copyright information in PMC

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