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Cervix.ppt (Read-Only)
Sonography of the Lower Uterine Segment and Cervix Mani Montazemi, RDMS Mani Montazemi, RDMS Cervix Manager of the Maternal Fetal Center Imaging Baylor Collage of Medicine Texas Children Hospital – Pavilion for Women Houston, Texas & Clinical Instructor / Faculty Thomas Jefferson University Hospital Philadelphia, Pennsylvania Least accurate method to measure cervical length & to identify a cervical funnel Mani Montazemi, RDMS Cervix Lower Uterine Segment Evaluation of the Cervix Predicting Preterm Delivery • Digital • Fetal Fibronectin • Ultrasound Transabdominal Translabial Transvaginal Mani Montazemi, RDMS Cervix J Ultrasound Med 22:239-241, 2003 Filling of the Bladder For Pelvic Sonograms Beryl R. Benacerraf, MD Mani Montazemi, RDMS Cervix Transabdominal Examination Pitfalls – Presenting fetal part – Bladder distension – Symphysis pubis cartilage – External os not visible – Critical angle artifact – Large maternal body habitus – Lower uterine contraction Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 1 Mani Montazemi, RDMS Cervix Transabdominal Examination Mani Montazemi, RDMS Cervix Transabdominal Examination Pitfalls – Presenting fetal part – Bladder distension – Symphysis pubis cartilage – External os not visible – Critical angle artifact – Large maternal body habitus – Lower uterine contraction Mani Montazemi, RDMS Cervix Transabdominal Examination Pitfalls – Presenting fetal part – Bladder distension – Symphysis pubis cartilage – External os not visible – Critical angle artifact – Large maternal body habitus – Lower uterine contraction Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Transabdominal Examination Pitfalls – Presenting fetal part – Bladder distension – Symphysis pubis cartilage – External os not visible – Critical angle artifact – Large maternal body habitus – Lower uterine contraction Mani Montazemi, RDMS Cervix 2 Transabdominal Examination Pitfalls – Presenting fetal part – Bladder distension – Symphysis pubis cartilage – External os not visible – Critical angle artifact – Large maternal body habitus – Lower uterine contraction Mani Montazemi, RDMS Cervix Transabdominal Examination Pitfalls – Presenting fetal part – Bladder distension – Symphysis pubis cartilage – External os not visible – Critical angle artifact – Large maternal body habitus – Lower uterine contraction Mani Montazemi, RDMS Cervix Placenta Previa: False Positives Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Lower Uterine Segment Contraction Post Void • Are common! • These contractions are very slow & long Mani Montazemi, RDMS Cervix “Contractions” Mani Montazemi, RDMS Cervix 3 “Contractions” “Contractions” Thick & asymmetric LUS Round myometrium Mani Montazemi, RDMS Cervix “Contractions” Mani Montazemi, RDMS Cervix Thick & asymmetric LUS Myometrial Thickness ≤ 1.5 cm “Contractions” Thick & asymmetric LUS Myometrial Thickness ≤ 1.5 cm Cervical length > 5 – 5.5cm Mani Montazemi, RDMS Cervix “Contractions” Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Thick & asymmetric LUS Myometrial Thickness ≤ 1.5 cm “Contractions” Thick & asymmetric LUS Myometrial Thickness ≤ 1.5 cm Cervical length > 5 – 5.5cm Cervical length > 5 – 5.5cm “S” shaped cervical canal “S” shaped cervical canal Mani Montazemi, RDMS Cervix 4 “Contractions” Thick & asymmetric LUS Myometrial Thickness ≤ 1.5 cm Cervical length > 5 – 5.5cm “S” shaped cervical canal Internal os cephalad to bladder reflection Mani Montazemi, RDMS Cervix If indicated, the cervical length should ALWAYS be measured with transvaginal approach Mani Montazemi, RDMS Cervix Common Indications for TV Evaluation of Cervix • Evaluating patients with vaginal bleeding to look for placenta previa • Fetal parts • Diagnosing cervical incompetence • Assessing cervical effacement and dilation in patients with preterm labor • Multiple Gestations • Post cerclage placement • History of preterm labor • Succenturiate lobed placentas • Velamentous cord insertion Mani Montazemi, RDMS Cervix Whether that’s due to incompetent cervix or preterm labor leading to preterm birth is the single most common cause of poor neonatal outcome Mani Montazemi, RDMS Cervix Preterm Delivery • • • • Preterm Delivery Transvaginal Approach Effects 8% of births Accounts for 15 – 20% of neonatal deaths 75% of non-anomaly deaths Treatment > $5 billion/yr USA Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 5 Transvaginal Approach Feet Anterior Posterior Good midline sagittal view of the cervix Head Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Anatomic Landmarks for Vaginal Sonography Anatomic Landmarks for Vaginal Sonography Bladder Chorion External Os Chorioamnion Membrane Cervical Length Internal Os Amnion Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Transvaginal Approach Transvaginal Approach Wall of the vagina * * Be careful - Excess Pressure Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 6 Transvaginal Approach Mani Montazemi, RDMS Cervix Excessive Probe Pressure Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Excessive Probe Pressure Mani Montazemi, RDMS Cervix Lower Uterine Segment Well developed Vs. Under developed Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 7 Earliest Time to Scan the Cervix Mani Montazemi, RDMS Cervix Landmarks Mani Montazemi, RDMS Cervix Landmarks Cervical Length • • • • Mani Montazemi, RDMS Cervix Upper limit of normal Average Lower limit of normal Pathologically decreased 5.0 cm 4.0 cm 3.0 cm 2.0 cm Mani Montazemi, RDMS Cervix Cervical Length “ One step” vs. “Two step” Technique Straight or Curved Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 8 Straight Cervix Mani Montazemi, RDMS Cervix Curved Cervix Mani Montazemi, RDMS Cervix Curved Cervix Cervical Changes • Essentially the same in – Term labor – Preterm labor – Cervical incompetence If height ≥ 5 mm “two step” technique Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Cervical Changes • Trust • Your • Vaginal • Ultrasound Mani Montazemi, RDMS Cervix Cervical Changes T Y V U Mani Montazemi, RDMS Cervix 9 Cervical Changes Cervical Changes • Dilation • Effacement • Funneling or Beaking • Posterior – caudal • Bulging membranes • Dilation Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix – Widening of the endocervical canal from side to side Cervical Changes • Effacement – Shortening of the cervix – Reduction of the cervical length from internal end to external end Cervical Changes • Funneling or Beaking – Extension of amniotic fluid for some variable distance (≥ 5mm) into the endocervical canal from internal os toward external os – ‘V’ shape • More common, triangular “notch” at the internal os – ‘U’ shape • Uncommon, typically larger than V-shaped variety • Usually deeper than it is broad and may be dynamic Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Cervical Changes Cervical Beaking – V Shape • Funneling or Beaking – Extension of amniotic fluid for some variable distance (≥ 5mm) into the endocervical canal from internal os toward external os – ‘V’ shape • More common, triangular “notch” at the internal os – ‘U’ shape • Uncommon, typically larger than V-shaped variety • Usually deeper than it is broad and may be dynamic Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 10 Cervical Funneling – U Shape Cervical Funneling Funnel Length > 1.6 cm Cervical Length < 2.0 cm Funnel Width >1.4 cm Sonographic Criteria Mani Montazemi, RDMS Cervix Diagnostic Challenge Mani Montazemi, RDMS Cervix Diagnostic Challenge Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Lower Uterine Segment Mani Montazemi, RDMS Cervix Diagnostic Challenge Mani Montazemi, RDMS Cervix 11 Diagnostic Challenge Cervical Changes to • Posterior Caudal – In the early to mid pregnancy the cervix points posteriorly toward the sacrum Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Cervical Changes to • Posterior Caudal • Bulging of membranes – In the early to mid pregnancy the cervix points posteriorly toward the sacrum – As the woman progresses towards labor the cervix starts to rotate to line up with vagina Mani Montazemi, RDMS Cervix Cervical Changes Soft – Fluid extends all the way to the external os – If into vagina, delivery likely unstoppable Mani Montazemi, RDMS Cervix Preterm Labor Preterm Labor “to evaluate for cervical dilation” “to evaluate for cervical dilation” BLADDER AF Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 12 Diagnostic Challenge Remember Cervical Change is Dynamic! Mani Montazemi, RDMS Cervix Cervix – Dynamic Changes Mani Montazemi, RDMS Cervix Cervix – Dynamic Changes Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Cervix – Dynamic Changes Mani Montazemi, RDMS Cervix Cervix – Dynamic Changes Mani Montazemi, RDMS Cervix 13 Cervical Stress Test with Gentle Pressure Mani Montazemi, RDMS Cervix Cervical Stress Test with Gentle Pressure Mani Montazemi, RDMS Cervix Don’t… Don’t… • Use cervical ultrasound as a screening test • Rely upon transabdominal ultrasound to measure length to identify a funnel. It is not reproducible because of the variable pressure created by the maternal bladder Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Don’t… Diagnostic Challenge • Measure cervical length before16 weeks, too much variation to be useful Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 14 Vasa Previa • Partial or complete obstruction of the internal cervical os by blood vessels Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Vasa Previa • • • • • Low lying placentas; Succenturiate lobed placentas; Velamentous cord insertion; Multiple pregnancies; Pregnancies resulting from IVF Risk Factors Most Common Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 15 Placenta Previa – Marginal Inferior edge of placenta within 2cm of IO Often resolves with advancing pregnancy Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Placenta Previa – Partial Placenta Previa – Complete Edge of placenta partially covers IO Difficult to differentiate from marginal previa Often resolves with advancing pregnancy Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Asymmetric complete previa Small part of placenta crosses IO May resolve with advancing pregnancy If > 1.5 cm crosses IO then less likely to resolve Placenta Previa – Complete 27 weeks Hospitalized with bleeding Symmetric complete previa Placenta centrally implanted on cervix Will not resolve with advancing pregnancy Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 16 3 weeks later • It is recognized that apparent placental position early in pregnancy may not correlate well with its location at the time of delivery • “Trophotropism” – The ability or the desire of the placenta to seek a blood supply – Proliferation of placental villi in areas of better blood supply (corpus , fundus) Kurt Benirschke, MD Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Trophotropism Mani Montazemi, RDMS Cervix Trophotropism Mani Montazemi, RDMS Cervix 17 Succenturiate lobe • May be low-lying or cross internal os Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix Mani Montazemi, RDMS Cervix 18 Introduction to Ultrasound Evaluation of the Cervix Thank You Mani Montazemi, RDMS Cervix Thank You Mani Montazemi, RDMS Cervix 19
