Quantitative Elastography of the Cervix for Predicting Labor Induction Success

Abstract

Purpose: To evaluate the role of quantitative elastography of the cervix in the prediction of successful labor induction compared to the Bishop score (BS) and ultrasound cervical length (CL).

Materials and Methods: A prospective pilot study was conducted between July 2010 and June 2011 in patients without preterm membrane rupture undergoing labor induction with vaginal prostaglandins. Before starting induction, the BS, functional CL and cervical tissue strain (TS) were assessed. TS assessment was performed twice using the Tissue Doppler Imaging (TDI) software. Diagnostic accuracy was evaluated for the prediction of the following endpoints: active labor achievement (success vs. failure, time interval < 24 h and < 48 h), vaginal delivery (success vs. failure, time interval < 36 h and < 72 h) and total amount of prostaglandins used for labor induction (< 6 mg and < 12 mg).

Results: We analyzed 77 patients with a mean gestational age of 39.7 ± 1.5 weeks of gestation and a mean strain of 0.75 ± 0.17. The TS significantly predicted a failure of labor induction, which occurred in 4 cases, both in mono- and multivariate analysis, independently of the functional cervical length (TS 0.6 ± 0.1). No correlation was found between the TS and other outcomes. The Bishop score and functional cervical length were found to predict only an early response to labor induction (time to active labor < 24 h, time to vaginal delivery < 36 h and PG usage < 6 mg). The diagnostic accuracy was slightly but not significantly improved if both TS and CL were considered.

Conclusion: Preliminary data show the possible usefulness of quantitative cervical elastography in the prediction of labor induction failure.

Zusammenfassung

Ziel: Untersuchung der Rolle der quantitativen zervikalen Elastografie im Vergleich zum Bischop-Score (BS) und zur sonografischen Zervixlänge (CL) in der Vorhersage einer erfolgreichen Geburtseinleitung.

Material und Methoden: Die prospektive Pilotstudie wurde bei Patientinnen ohne vorzeitigen Blasensprung und vor der Geburtseinleitung mit vaginalen Prostaglandinen durchgeführt. Vor Beginn der Einleitung wurden der BS, die funktionelle CL und die zervikale Gewebe-Steifigkeit (TS) bestimmt. Die TS-Messung wurde zweimal mittels Tissue Doppler Imaging (TDI) Software durchgeführt. Die diagnostische Genauigkeit für die Vorhersage der folgenden Endpunkte wurde ausgewertet: aktive Geburtsphase (Erfolg vs. Therapieversagen, Zeitintervall < 24 und < 48 Std.), vaginale Entbindung (Erfolg vs. Therapieversagen, Zeitintervall < 36 und < 72 Stud.) und die gesamte Menge der eingesetzten Prostaglandine (< 6 und < 12 mg).

Ergebnisse: Es wurden 77 Patientinnen mit einem mittleren Gestationsalter von 39,7 ± 1,5 Schwangerschaftswochen untersucht. Der mittlere TS betrug 0,75 ± 0,17. Der TS sagte signifikant ein Versagen der Geburtseinleitung, welches in 4 Fällen aufgetreten ist, unabhängig von der CL, voraus (TS 0,6 ± 0,1). Es wurde keine Korrelation zwischen TS und andere Ergebnisse festgestellt. Der BS und die CL konnten nur eine frühzeitige Antwort auf eine Geburtseinleitung vorhersagen (Zeit bis zur aktiven Geburtsphase < 24 Std., Zeit bis zur vaginalen Entbindung < 36 Std. und PG-Nutzung < 6 mg). Die diagnostische Genauigkeit unter Berücksichtigung des TS und der CL konnte leicht, aber nicht signifikant, verbessert werden.

Schlussfolgerungen: Die vorläufigen Daten zeigen einen möglichen Nutzen der quantitativen zervikalen Elastografie in der Vorhersage einer frustranen Geburtseinleitung.

Key words

cervix - ultrasound Doppler - obstetrics - tissue elastography - tissue doppler imaging - labor induction - sensitivity and specifity

• References

• 1 Ophir J, Cespedes I, Ponnekanti H et al. Elastography: a quantitative method for imaging the elasticity of biological tissues. Ultrasonic imaging 1991; 13: 111-134
• 2 Palmeri ML, Nightingale KR. What challenges must be overcome before ultrasound elasticity imaging is ready for the clinic?. Imaging in medicine 2011 ; 3: 433-444
• 3 Garra BS. Imaging and estimation of tissue elasticity by ultrasound. Ultrasound Q 2007 ; 23: 255-268
• 4 Sutherland GR, Hatle L, Claus P et al. Myocardial Motion/Deformation – Principles. Doppler Myocardial Imaging, A Textbook. Hasselt-Belgium: BSWK Scientific Consulting and Publishing; 2006: 5-18
• 5 D'Hooge J, Heimdal A, Jamal F et al. Regional strain and strain rate measurements by cardiac ultrasound: principles, implementation and limitations. Eur J Echocardiogr 2000 ; 1: 154-170
• 6 Fruscalzo A, Schmitz R, Klockenbusch W et al. Reliability of cervix elastography in late first and second trimester of pregnancy. Ultraschall in Med 2012; 33: 1-7
• 7 Fruscalzo A, Steinhard J, Londero AP et al. Reliability of quantitative elastography of the uterine cervix in at-term pregnancies. J Perinat Med 2013; 7: 1-7
• 8 Mella MT, Berghella V. Prediction of preterm birth: cervical sonography. Semin Perinatol 2009 ; 33: 317-24
• 9 Bishop EH. Pelvic Scoring for Elective Induction. Obstet Gynecol 1964 ; 24: 266-268
• 10 Friedman EA. Primigravid labor; a graphicostatistical analysis. Obstet Gynecol 1955 ; 6: 567-589
• 11 Seitz K. Elastografie in der Ultraschalldiagnostik: raus aus den Kinderschuhen? . Ultraschall in Med 2009; 30: 301-302
• 12 Gheonea DI, Saftoiu A. New Trends in Elasticity Imaging. Ultraschall in Med 2010; 31: 525-527
• 13 Bamber J, Cosgrove D, Dietrich CF et al. EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography. Part 1: Basis Principles and Technology. Ultraschall in Med 2013; 34: 169-184
• 14 Cosgrove D, Piscaglia F, Bamber J et al. EFSUMB Guidelines and Recommendations on the Clinical Use of Ultrasound Elastography. Part 2: Clinical Applications. Ultraschall in Med 2013; 34: 238-253
• 15 Feltovich H, Hall TJ, Berghella V. Beyond cervical length: emerging technologies for assessing the pregnant cervix. Am J Obstet Gynecol 2012; 207: 345-354
• 16 Feltovich H, Hall TJ. Quantitative imaging of the cervix: setting the bar. Ultrasound Obstet Gynecol 2013 ; 41: 121-128
• 17 Swiatkowska-Freund M, Preis K. Elastography of the uterine cervix: implications for success of induction of labor. Ultrasound Obstet Gynecol 2011 ; 38: 52-56
• 18 Molina FS, Gomez LF, Florido J et al. Quantification of cervical elastography: a reproducibility study. Ultrasound Obstet Gynecol 2012 ; 39: 685-689
• 19 Fruscalzo A, Schmitz R. Quantitative cervical elastography in pregnancy. Ultrasound Obstet Gynecol 2012 ; 40: 612
• 20 Hernandez-Andrade E, Hassan SS, Ahn H et al. Evaluation of cervical stiffness during pregnancy using semiquantitative ultrasound elastography. Ultrasound Obstet Gynecol 2012; 41: 152-156
• 21 Iams JD. Cervical ultrasonography. Ultrasound Obstet Gynecol 1997 ; 10: 156-160
• 22 Burger M, Weber-Rossler T, Willmann M. Measurement of the pregnant cervix by transvaginal sonography: an interobserver study and new standards to improve the interobserver variability. Ultrasound Obstet Gynecol 1997 ; 9: 188-193
• 23 Hatfield AS, Sanchez-Ramos L, Kaunitz AM. Sonographic cervical assessment to predict the success of labor induction: a systematic review with metaanalysis. Am J Obstet Gynecol 2007 ; 197: 186-192
• 24 Rozenberg P, Chevret S, Chastang C et al. Comparison of digital and ultrasonographic examination of the cervix in predicting time interval from induction to delivery in women with a low Bishop score. BJOG 2005 ; 112: 192-196
• 25 Keepanasseril A, Suri V, Bagga R et al. Pre-induction sonographic assessment of the cervix in the prediction of successful induction of labour in nulliparous women. Aust N Z J Obstet Gynaecol 2007 ; 47: 389-393
• 26 Reis FM. Prediction of successful induction of labor at term: role of clinical history, digital examination, ultrasound assessment of the cervix, and fetal fibronectin assay. American journal of obstetrics and gynecology 2003; 189: 1361
• 27 Lange AP, Secher NJ, Westergaard JG et al. Prelabor evaluation of inducibility. Obstet Gynecol 1982 ; 60: 137-147
• 28 Parra-Saavedra M, Gomez L, Barrero A et al. Prediction of preterm birth using the cervical consistency index. Ultrasound Obstet Gynecol 2011 ; 38: 44-51