OP04.04: Development of an in vivo quantitative ... - Wiley Online Library

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practice: The role of the advanced practice sonographer. B. R. Benacerraf. Harvard Medical School, Boston, United States. Objectives: To evaluate the use of the ...
18th World Congress on Ultrasound in Obstetrics and Gynecology

OP04.04 Development of an in vivo quantitative ultrasound methodology to scan the cervix B. L. McFarlin1 , M. L. Oelze2 , T. A. Bigelow3 , E. K. Chien4 , H. Ji5 , W. D. O’Brien, Jr. 2 1

Maternal Child Nursing, University of Illinois at Chicago, Chicago, United States, 2 Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, United States, 3 Department of Electrical Engineering, University of North Dakota, Grand Forks, United States, 4 Obstetrics and Gynecology, Brown University/Women’s and Infants Hospital of Rhode Island, Providence, United States, 5 Department of Obstetrics and Gynecology, Brown University/Women’s and Infants Hospital of Rhode Island, Providence, United States Objectives: The cause of ultrasound scattering in tissues has been hypothesized to be related to the amount of collagen, elastin and to the structure and function of the extracellular matrix. Our prior work demonstrated that the decreased collagen concentration in cervical ripening clearly affected ultrasound scattering from the tissue. Before our work can be translated for use in humans to detect cervical changes in pregnancy, an in vivo quantitative ultrasound (QUS) methodology needed to be developed. Methods: Five timed-pregnant groups (day 15, 17, 19, 20, & 21 of pregnancy) and a non-pregnant group of randomly assigned Sprague-Dawley rats, (8 rats/group) were ultrasonically scanned under anesthesia with a 40-MHz custom miniature vaginal transducer (NIH Transducer Resource Center) then euthanized and the cervix harvested. Ultrasonic scatterer property estimates (average scatterer diameter [ASD], acoustic concentration [AC]) from the cervices were quantified and then compared to hydroxyproline, soluble collagen (uncross-linked), insoluble collagen (non-extractable) {Sircol TM assay [Biocolor, UK]}. Attenuation was measured for each cervix and used to estimate scatterer properties. The attenuation algorithm was verified via computer simulations and an ex vivo tissue sample. The attenuation accuracy was better than 15%. Results: Gestational day was correlated with cervical: ASD, AC, (P < 0.03); hydroxyproline, tropocollagen, soluble and insoluble collagen (P < 0.0001). The differences among gestational groups were very small (effect size = 0.13), suggestive of biologic variability, that is, a single QUS measurement of the cervix is less likely to detect significant changes than repeated longitudinal measurements in the same animal. Conclusions: The findings of this study will be used to guide longitudinal in vivo studies to predict and validate cervical changes during pregnancy.

OP04.05 Dynamic magnetic resonance imaging (DMR) and three dimensional extended imaging (3DXI) in the first trimester diagnosis of placenta percreta: A three cases report J. L. Duque, C. Torres, S. Molina, D. A. Alfonso, A. Motta Maternal Fetal Medicine, Fetal Medicine Unit-Medicina Perinatal LTDA., Bogota, Colombia Placenta percreta is a life threatening obstetrical condition. Diagnosis is often achieved by conventional ultrasound imaging at second half

Oral poster abstracts

of pregnancy leading to multiple and severe complications. Due to its increasing incidence, a reliable and earlier antenatal diagnosis is needed. We describe prenatal assessment, outcome and pathological anatomy of placenta percreta in three early diagnosed cases before 11 weeks with conventional two dimensional (2D) and three dimensional (3D) ultrasound and using novel techniques as DMR and 3DXI. As long as we know these are the earliest cases reported. We describe conventional 2D and 3D ultrasound imaging findings supplemented by DMR and 3DXI in three cases of first trimester diagnosed placenta percreta with the use of Accuvix XQ ultrasonographic equipment (Medison. Seoul, Korea). The obtained data were analyzed in the post-processor software 3DXI viewer (V1.00.0518, Medison, Seoul, Korea) and correlated with clinical and pathological findings. Conventional sonographic examination revealed bulging of placental tissue to uterine serosa at first trimester in patients with morbidly-adherent placenta. DMR and 3DXI confirmed previous findings and revealed the depth and extend of placental invasion into the miometrium. DMR and 3DXI are useful additional methods to diagnose and classify morbidly-adherent placenta.

OP04.06 A collaborative approach to a high volume ultrasound practice: The role of the advanced practice sonographer B. R. Benacerraf Harvard Medical School, Boston, United States Objectives: To evaluate the use of the advanced practice sonographer (APS) in conjuction with staff sonographers, to improve the efficiency of a busy OB GYN sonography practice and enable a single physician to evaluate 85 patients in one work day. Methods: One day, selected at random in a busy practice of OB GYN sonography is examined during which one physician, 2 APS and 7 staff sonographers examined 86 patients. Each patient was first scanned by a staff sonographer and triaged according to sonographic findings or clinical circumstance. Patients were either rescanned by a physician or an APS, or the images taken by the staff sonographer were then reviewed by the physician in cases of followup or limited scans. The physician supervised all scans. The workflow algorithm was designed to optimize the physican’s time while integrating the skills of the APS and staff sonographers. Results: From 7 : 30AM- to 4 : 40PM, 85 patients were scanned with one supervising physician. There were 72 obstetrical and 13 gynecological scans. All gyncolgical scans were scanned by a staff sonographer and the physician. After the standard staff sonographer’s scan, 36 of the total 72 OB patients were rescanned by the APS under the supervision of the physician (but not rescanned by the physician)(Table 1). The physician scanned the 8 abnormalities (sacrococcygeal teratoma, limb abnormality, placenta accreta, renal anomalies (3), hyperechoic bowel, choroids plexus cysts), as well 9 of the second trimester high risk anatomy patients of which 2 had an echogenic intracardiac focus seen by the sonographer, one 1st trimester failed pregnancy and the 8 amniocentesis patients. The staff sonographers performed the remaining 20 scans (1st trimester or follow up growth scans) and images were reviewed by the physician. Conclusions: This study shows that one physician, APS and sonographers can work as a team to optimize physican time while using additional skills of the APS.

Table OP04.06: Table Scanner

TOTAL APS Sonographer only Physician

322

2nd Trimester

Twins

First Trimester

3rd Trimester

Amnio

26 17 anatomic surveys 0 9 high risk (2 EIF)

5 3 (1 2nd and 2 3rd tri) rd 2 (f/u 3 trimester growth 0

11 0 10(5NT, 5 viability) 1 (MAB)

14 6 growth or placental location 8 (f/u growth) 0

8 0 0 8 procedures

Anomalies

8 (2nd

8 0 0 opinions and anomalies

Ultrasound in Obstetrics & Gynecology 2008; 32: 308–397