Development of an Ultrasonic Method to Detect Cervical Remodeling in Vivo in Full-Term Pregnant Women

The objective of this study was to determine whether estimates of ultrasonic attenuation could detect changes in the cervix associated with medically induced cervical remodeling. Thirty-six full-term pregnant women underwent two transvaginal ultrasonic examinations separated in time by 12 h to determine cervical attenuation, cervical length and changes thereof. Ultrasonic attenuation and cervical length data were acquired from a zone (Zonare Medical Systems, Mountain View, CA, USA) ultrasound system using a 5–9 MHz endovaginal probe. Cervical attenuation and cervical length significantly decreased in the 12 h between the pre-cervical ripening time point and 12 h later. The mean cervical attenuation was 1.1 ± 0.4 dB/cm-MHz before cervical ripening agents were used and 0.8 ± 0.4 dB/cm-MHz 12 h later (p \u3c 0.0001). The mean cervical length also decreased from 3.1 ± 0.9 cm before the cervical ripening was administered to 2.0 ± 1.1 cm 12 h later (p \u3c 0.0001). Cervical attenuation and cervical length detected changes in cervical remodeling 12 h after cervical ripening administration

Beyond Cervical Length: A Pilot Study of Ultrasonic Attenuation for Early Detection of Preterm Birth Risk

The purpose of this study was to determine whether cervical ultrasonic attenuation could identify women at risk of spontaneous preterm birth. During pregnancy, women (n = 67) underwent from one to five transvaginal ultrasonic examinations to estimate cervical ultrasonic attenuation and cervical length. Ultrasonic data were obtained with a Zonare ultrasound system with a 5- to 9-MHz endovaginal transducer and processed offline. Cervical ultrasonic attenuation was lower at 17–21 wk of gestation in the SPTB group (1.02 dB/cm-MHz) than in the full-term birth groups (1.34 dB/cm-MHz) (p = 0.04). Cervical length was shorter (3.16 cm) at 22–26 wk in the SPTB group than in the women delivering full term (3.68 cm) (p = 0.004); cervical attenuation was not significantly different at this time point. These findings suggest that low attenuation may be an additional early cervical marker to identify women at risk for SPTB

Using speckle statistics to improve attenuation estimates for cervical assessment

Preterm birth is a major contributor to infant mortality worldwide. Cervical length and previous history of preterm birth are the only two indicators which can help in identifying preterm birth but have a low positive identifying rate. Quantitative ultrasound parameters like attenuation can provide additional details about the tissue microstructure besides the diagnostic image. Attenuation can be used to detect preterm cases as the attenuation decreases with the increasing gestation age and this decrease can be seen earlier in cases of preterm birth. The algorithm and the size of the region of interest (ROI) play a vital role in calculating valid estimates of attenuation. In this paper, we compared the ability of the Spectral log difference algorithm and the Spectral difference algorithm to detect changes in the cervix leading to delivery for both full term and preterm births under varying ROI sizes. Spectral log difference yields a more consistent decrease in the attenuation as we approach delivery for both the preterm and full term patients. ROI size doesn\u27t significantly alter the observed trends for this study. For preterm birth a maximum decreases of 0.35dB/cm-MHz was observed. The bias in attenuation algorithms can be removed by selecting homogenous regions inside the cervix, but the cervix is a heterogeneous tissue. Gamma mixture model is used to segment the cervix into different tissue types and attenuation algorithm are then applied to individual tissue type to get an estimate of attenuation. The area under the receiver operating characteristic curve increases from 56% to 80% when gamma mixture model is used for segmentation