Quantitative Ultrasound Parameters Based on the Backscattered Echo Power Signal as Biomarkers of Cervical Remodeling: A Longitudinal Study in the Pregnant Rhesus Macaque

Abstract

Clinical prediction and especially prevention of abnormal birth timing, particularly preterm, is poor. The cervix plays a key role in birth timing; it first serves as a rigid barrier to protect the developing fetus, then becomes the pathway to delivery of that fetus. Imaging biomarkers to define this remodeling process could provide insights to improve prediction of birth timing and elucidate novel targets for preventive therapies. Quantitative ultrasound (QUS) approaches that appear promising for this purpose include shear wave speed (SWS) estimation to quantify softness as well as parameters based on backscattered power, such as the mean backscattered power difference (mBSPD) and specific attenuation coefficient (SAC), to quantify organization of tissue microstructure. Invasive studies in rodents demonstrated that, as pregnancy advances, cervical microstructure disorganizes as tissue softness and compliance increase. Our noninvasive studies in pregnant women and Rhesus macaques suggested that QUS can detect these microstructural changes in vivo. Our previous study in the same cohort showed a progressive decline in SWS during pregnancy, consistent with increasing tissue softness, and we hypothesized that backscatter parameters would also decrease, consistent with increasing microstructural disorganization. In this study, we analyzed mBSPD and the SAC in the cervices of Rhesus macaques (n=18). We found that both mBSPD and SAC decrease throughout pregnancy (p < 0.001 for both parameters), and *

Labour and delivery: a clinician's perspective on a biomechanics problem

“…Our group of clinicians, physicists and engineers is pursuing answers to these questions. We have learned that properties such as cervical softness and microstructural organization can be objectively quantified in pregnant women and rhesus macaques, and that they dramatically change as pregnancy royalsocietypublishing.org/journal/rsfs Interface Focus 9: 20190032 progresses [40][41][42][43]. We have also learned that the area of the internal os contains circumferentially oriented smooth muscle cells, which may operate as a sort of sphincter at this critical junction between the cervix, membranes and uterus [44].…”

Investigation of backscatter factor in medical radiography using anthropomorphic phantom by optically stimulated luminescence dosimeter

“…Evaluating the backscatter is important and has extensive applications in other fields such as ultrasound and optics which employ backscatter concept in the form of backscatter parameters and also backscatter statistics for different purposes like tissue characterization [17][18][19].…”