Abstract
Background In a normal pregnancy, cervical collagen fibers remain organized in predictable patterns
throughout most of the gestation. Cervical remodeling reflects a rearrangement of
collagen fibers in which they become increasingly disordered and contribute to the
pathogenesis of spontaneous preterm birth. Quantitative ultrasound analysis of cervical
tissue echotexture may have the capacity to identify microstructural changes before
the onset of cervical shortening.
Objective The primary objective of this study was to examine the utility of a novel quantitative
sonographic marker, the cervical heterogeneity index (HI), which reflects the relative
organization of cervical collagen fibers. Also, we aimed to determine an optimal HI
cut-point to predict spontaneous preterm birth.
Study Design This retrospective cohort study employed a novel image-processing technique on transvaginal
ultrasound images of the cervix in gestations between 14 and 28 completed weeks. The
transvaginal sonography images were analyzed in MATLAB (MathWorks, Natick, MA) using
a custom image-processing technique that assessed the relative heterogeneity of the
cervical tissue.
Results A total of 151 subjects were included in the study. The mean HI in subjects who delivered
preterm and at term was 8.28 ± 3.73 and 12.35 ± 5.80, respectively (p < 0.0001). Thus, decreased tissue heterogeneity was associated with preterm birth,
and increased tissue heterogeneity was associated with delivery at term. In our study
population, preterm birth was associated with a short cervix (<2.5 cm), history of
preterm birth and lower HI, and our findings indicate that HI may improve prediction
of preterm birth.
Conclusion Quantitative ultrasound measurement of the cervical HI is a promising, noninvasive
tool for early prediction of spontaneous preterm birth.
Keywords
cervix uteri - diagnostic imaging - quantitative ultrasound - pregnancy - premature
birth - ultrasonography
