Cervix Elasticity and Length Measurements With Tactile-Ultrasound Probe: First Clinical Experience [32J

Abstract

INTRODUCTION: Premature cervix softening and shortening may be considered an early mechanical failure that predisposes to preterm birth. Clinical studies demonstrate that cervical elastography may be able to predict spontaneous preterm delivery. The purpose of the study was to access a new approach to cervix elasticity and length measurements based on the acquisition of stress-strain data by tactile and ultrasound transducers. METHODS: A Cervix Monitor (CM) was designed to provide a single-use, inexpensive cervix probe with a tactile array and an ultrasound transducer. 10 non-pregnant and 10 pregnant women at 22-29 weeks of pregnancy were examined with the CM in IRB approved studies. Cervix stress-to-strain ratio was used to calculate cervix elasticity (Young's modulus) for four cervix sectors at 3, 6, 9, and 12 o'clock. RESULTS: The study with non-pregnant women demonstrated the device safety. The study with pregnant women with gestational age 25.4±2.3 weeks demonstrated cervix elasticity 19.7±15.4 kPa and length 30.7±6.6 mm. Intraclass correlation coefficients between two measurements at the same cervix sector were found to be 0.97 for cervix elasticity and 0.93 for cervix length. The bias and the 95% limits of agreement (Bland-Altman plot) of cervix elasticity measurement are 3.8% and -22.4% to +14.9%, the precision was 9.5%. The bias and the 95% limits of agreement of cervix length measurement are -1.6% and -13.3% to +16.5%, the precision was 7.6%. CONCLUSION: The CM stress-strain data allowed computation of cervix elasticity and length. This approach has a potential to provide cervix markers to predict spontaneous preterm delivery in a cost-effective manner.