Yan Yan1, Maryam Basij1, Alpana Garg2, Aneesha Varrey3,4, Ali Alhousseini4,5,6, Richard Hsu3, Edgar Hernandez-Andrade3,7, Roberto Romero3,8,9,10,11,12, Sonia S Hassan4,5,13, Mohammad Mehrmohammadi1,4,14,15. 1. Department of Biomedical Engineering, Wayne State University College of Engineering, Detroit, Michigan, United States of America. 2. Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan, United States of America. 3. Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Perinatology Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland and Detroit, Michigan, United States of America. 4. Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America. 5. Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America. 6. Department of Obstetrics and Gynecology, William Beaumont Hospital, Royal Oak, Michigan, United States of America. 7. Department of Obstetrics and Gynecology and Reproductive Sciences, McGovern Medical School, University of Texas, Health Science Center at Houston (UTHealth), Houston, Texas, United States of America. 8. Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan, United States of America. 9. Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, Michigan, United States of America. 10. Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan, United States of America. 11. Detroit Medical Center, Detroit, Michigan, United States of America. 12. Department of Obstetrics and Gynecology, Florida International University, Miami, Florida, United States of America. 13. Office of Women's Health, Wayne State University School of Medicine, Detroit, Michigan, United States of America. 14. Department of Electrical and Computer Engineering, Wayne State University, Detroit, Michigan, United States of America. 15. Barbara Ann Karmanos Cancer Institute, Detroit, Michigan, United States of America.
Abstract
OBJECTIVE: Cervical remodeling is an important component in determining the pathway of parturition; therefore, assessing changes in cervical tissue composition may provide information about the cervix's status beyond the measurement of cervical length. Photoacoustic imaging is a non-invasive ultrasound-based technology that captures acoustic signals emitted by tissue components in response to laser pulses. This optical information allows for the determination of the collagen-to-water ratio (CWR). The purpose of this study was to compare the CWR evaluated by using spectroscopic photoacoustic (sPA) imaging in cervical samples obtained from pregnant and non-pregnant women. METHODS: This cross-sectional study comprised cervical biopsies obtained at the time of hysterectomy (n = 8) and at the scheduled cesarean delivery in pregnant women at term who were not in labor (n = 8). The cervical CWR was analyzed using a fiber-optic light-delivery system integrated to an ultrasound probe. The photoacoustic signals were acquired within the range of wavelengths that cover the peak absorption of collagen and water. Differences in the CWR between cervical samples from pregnant and non-pregnant women were analyzed. Hematoxylin and eosin and Sirius Red stains were used to compare the collagen content of cervical samples in these two groups. RESULTS: Eight cervix samples were obtained after hysterectomy, four from women ≤41 years of age and four from women ≥43 years of age; all cervical samples (n = 8) from pregnant women were obtained after 37 weeks of gestation at the time of cesarean section. The average CWR in cervical tissue samples from pregnant women was 18.7% (SD 7.5%), while in samples from non-pregnant women, it was 55.0% (SD 20.3%). There was a significantly higher CWR in the non-pregnant group compared to the pregnant group with a p-value <0.001. A subgroup analysis that compared the CWR in cervical samples from pregnant women and non-pregnant women ≤41 years of age (mean 46.3%, SD 23.1%) also showed a significantly higher CWR (p <0.01). Lower collagen content in the pregnancy group was confirmed by histological analysis, which revealed the loss of tissue composition, increased water content, and collagen degradation. CONCLUSION: The proposed bimodal ultrasound and sPA imaging system can provide information on the biochemical composition of cervical tissue in pregnant and non-pregnant women. Photoacoustic imaging showed a higher collagen content in cervical samples from non-pregnant women as compared to those from pregnant women, which matched with the histological analysis. This novel imaging method envisions a new potential for a sensitive diagnostic tool in the evaluation of cervical tissue composition.
<span class="abstract_title">OBJECTIVE: Cervical remodeling is an important component in determining the pathway of parturition; therefore, assessing changes in cervical tissue composition may provide information about the cervix's status beyond the measurement of cervical length. Photoacoustic imaging is a non-invasive ultrasound-based technology that captures acoustic signals emitted by tissue components in response to laser pulses. This optical information allows for the determination of the collagen-to-<span class="Chemical">waterratio (CWR). The purpose of this study was to compare the CWR evaluated by using spectroscopic photoacoustic (sPA) imaging in cervical samples obtained from pregnant and non-pregnant women. METHODS: This cross-sectional study comprised cervical biopsies obtained at the time of hysterectomy (n = 8) and at the scheduled cesarean delivery in pregnant women at term who were not in labor (n = 8). The cervical CWR was analyzed using a fiber-optic light-delivery system integrated to an ultrasound probe. The photoacoustic signals were acquired within the range of wavelengths that cover the peak absorption of collagen and water. Differences in the CWR between cervical samples from pregnant and non-pregnant women were analyzed. Hematoxylin and eosin and Sirius Red stains were used to compare the collagen content of cervical samples in these two groups. RESULTS: Eight cervix samples were obtained after hysterectomy, four from women ≤41 years of age and four from women ≥43 years of age; all cervical samples (n = 8) from pregnant women were obtained after 37 weeks of gestation at the time of cesarean section. The average CWR in cervical tissue samples from pregnant women was 18.7% (SD 7.5%), while in samples from non-pregnant women, it was 55.0% (SD 20.3%). There was a significantly higher CWR in the non-pregnant group compared to the pregnant group with a p-value <0.001. A subgroup analysis that compared the CWR in cervical samples from pregnant women and non-pregnant women ≤41 years of age (mean 46.3%, SD 23.1%) also showed a significantly higher CWR (p <0.01). Lower collagen content in the pregnancy group was confirmed by histological analysis, which revealed the loss of tissue composition, increased water content, and collagen degradation. CONCLUSION: The proposed bimodal ultrasound and sPA imaging system can provide information on the biochemical composition of cervical tissue in pregnant and non-pregnant women. Photoacoustic imaging showed a higher collagen content in cervical samples from non-pregnant women as compared to those from pregnant women, which matched with the histological analysis. This novel imaging method envisions a new potential for a sensitive diagnostic tool in the evaluation of cervical tissue composition.
Authors: Laura E Masson; Christine M O'Brien; Rekha Gautam; Giju Thomas; James C Slaughter; Mack Goldberg; Kelly Bennett; Jennifer Herington; Jeff Reese; Emad Elsamadicy; J Michael Newton; Anita Mahadevan-Jansen Journal: Am J Obstet Gynecol Date: 2022-02-19 Impact factor: 10.693