Placental Disorders Imaging Guidelines
Tips for Diagnosis Document placental location Relationship to internal cervical os Mani Montazemi, RDMS Placental appearance Director of Ultrasound Education & Quality Assurance Placental cord insertion assessment Baylor College of Medicine Division of Maternal-Fetal Medicine Maternal Fetal Center Imaging Manager Texas Children’s Hospital, Pavilion for Women Houston Texas & Clinical Instructor Thomas Jefferson University Hospital - Radiology Department Mani Montazemi, RDMSPhiladelphia, Pennsylvania Mani Montazemi, RDMS Placenta Placenta
Placenta Placenta
Mani Montazemi, RDMS Placenta
Placental Size Placental Size – Imaging Pitfalls
• Placental thickness ↑ with gestation • Subplacental veins • > 4 cm is considered abnormally thick • Acute placental hemorrhage • Myometrial contraction • Fibroids
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
1 Placental Thickening Placental Thickening: Maternal
• Maternal • Anemia • Fetal • Diabetes • Placental • Intrauterine infections
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Placental Thickening: Fetal
• Hydrops • Macrosomia • Diabetes • Infections • Neoplasms • Beckwith-Wiedemann Syndrome • Umbilical vein obstruction • High output cardiac failure – AVM, Chorioangioma, sacrococcygeal teratoma, cardiac anomaly etc.
Mani Montazemi, RDMS Placenta
Placental Thickening: Placental Placental Size – Too Small
• H. mole • Intrauterine growth impairment • Hemorrhage • Preeclampsia • Chromosomal abnormalities (usually triploidy) • Placental infarction • Polyhydramnios
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
2 Diagnostic Challenge Circumvallate Placenta
Echogenic rim of placental tissue at edge of placenta • A double layer of amnion & chorion, as well as necrotic villi & fibrin, form a raised white ring around the surface of the placenta disk at a variable distance from the umbilical cord insertion site
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Circumvallate Placenta Circumvallate Placenta
Differential diagnosis • Amniotic sheet (Synechia) • Amniotic band
Difficult diagnosis only 10% identified
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Interpretation Tips Interpretation Tips
“Look carefully at attachment points” “Look carefully at attachment points” • Circumvallate placenta • Circumvallate placenta – Membranes attach only on placenta – Membranes attach only on placenta • Synechia • Synechia – Membranes attach to uterine wall – Membranes attach to uterine wall • Amniotic band • Amniotic band – Membranes attach to fetus – Membranes attach to fetus
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
3 Interpretation Tips Amniotic Band
“Look carefully at attachment points” • 2o to amniotic membrane rupture • Circumvallate placenta • This causes amniotic fibrous bands to float in – Membranes attach only on placenta the amniotic fluid and potentially wrap around • Synechia parts of the baby or umbilical cord – Membranes attach to uterine wall • Amniotic band – Membranes attach to fetus
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Amniotic Band Amniotic Band
• Spectrum of asymmetric disruption deformities & amputations – Absent digits, limbs, or portions of limbs – Facial clefts – Cranial & abdominal wall disruption
Mani Montazemi, RDMS Placenta
Amniotic Band Amniotic Band
Constriction Point Distal Edema Left Leg
20 weeks GA
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
4 Amniotic Band Amniotic Band
Left Right
Umbilical cord Left leg Amniotic band
Edematous Left foot Arterial Flow Decresed
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Amniotic Band Amniotic Band
Intrauterine YAG-Laser band release Lucía was born at 28 weeks gestation
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Amniotic Band Amniotic Band
BAND RESECTION AND MULTIPLE Z-PLASTY
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
5 Succenturiate Lobe of the Placenta Identify Communicating Vessels
• One or more extra lobes of the placenta separated from the body of the placenta
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Identify Communicating Vessels
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
6 Identify Cord Insertion Site Succenturiate Lobe of the Placenta
• Succenturiate lobe + vasa previa Differential diagnosis: – 60-80% fetal mortality if not diagnosed prenatally • Subchorionic hemorrhage • Myometrial contraction • Uterine myoma
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Caution! Caution!
Placenta SAG
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Diagnostic Challenge
Mani Montazemi, RDMS Placenta
7 Diagnostic Challenge Velamentous Cord Insertion
Insertion of cord into membranes before entering the placenta
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Velamentous Cord Insertion Velamentous Cord Insertion
The velamentous vessels are surrounded only by fetal • Suspect when marginal placental insertion membranes, with no Wharton's jelly, thus they are • Diagnosis made with Doppler color flow prone to compression or disruption
Mani Montazemi, RDMS Cord appears to insert directly on uterine wall Mani Montazemi, RDMS Placenta Placenta
Velamentous Cord Insertion Velamentous Cord Insertion
Remember • Find both CI sites in monochorionic twins
Normal placenta CI site not seen “Twins have 6 to 9 times higher incidence” Mani Montazemi, RDMS VCI branching vessels are submembranous Mani Montazemi, RDMS Placenta Placenta
8 Velamentous Cord Insertion
• Velamentous insertion of the umbilical cord in one of • Velamentous cord insertion associated with the twins is a significant risk factor for TTTS 13x increase in discordant birth weight
R D
Mani Montazemi, RDMS Mani Montazemi, RDMS Multiple Gestations Multiple Gestations
Vasa Previa Diagnostic Challenge
• Partial or complete obstruction of the internal cervical os by blood vessels
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
9 Vasa Previa
• Low lying placentas; • Succenturiate lobed placentas; • Velamentous cord insertion; Risk Factors • Multiple pregnancies; • Pregnancies resulting from IVF
Most Common Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
False Positive Vasa Previa Placenta Previa – Risk Factors
• Obligate cord presentation • Previous placenta previa • Prior cesarean deliveries • Marginal vein • Multiple gestation • Cervical varices • Increasing parity – incidence 0.2 % in nulliparas versus up to 5 % in grand multiparas • Maternal age – higher in older nulliparous females • Number of curettages for spontaneous or induced abortions • Smoking • Cocaine use
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Risk of Previa Placenta Previa – Marginal
• 0.26% If no prior C-section • 0.65% If 1 prior C-section • 1.8% If 2 prior C-section • 3.0% If 3 prior C-section • 10.0% If 4 or more prior C-section
Clark 1985 Inferior edge of placenta within 2cm of IO Often resolves with advancing pregnancy
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
10 Placenta Previa – Partial
Edge of placenta partially covers IO Difficult to differentiate from marginal previa Often resolves with advancing pregnancy Mani Montazemi, RDMS Placenta
Placenta Previa – Complete Placenta Previa – Complete
Asymmetric complete previa Symmetric complete previa Small part of placenta crosses IO Placenta centrally implanted on cervix May resolve with advancing pregnancy Will not resolve with advancing pregnancy Mani Montazemi, RDMS If > 1.5 cm crosses IO then less likely to resolve Mani Montazemi, RDMS Placenta Placenta
Remember
27 weeks Hospitalized with bleeding Use TVUS to R/O placenta previa in all patients with bleeding in 2nd & 3rd trimester
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
11 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 Mani Montazemi, RDMS Placenta Placenta
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Consequence of Placenta Migration Succenturiate lobe
• Regressing previa • May be low-lying or cross internal os • Succenturiate lobe • Vasa previa • Migration cord origin • Velementous cord origin
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
12 Trophotropism Placenta Previa: False Positives
• Overfilling of the bladder • Uterine contraction • Fibroid low in the uterus
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Reminder • The placenta’s relationship to the IO should be assessed in every scan. Failure to see the inferior edge of the placenta should lead to TV scanning to R/0 previa if not previously done in the 2nd trimester • A previa can be missed near term if the fetal head is low in the pelvis
Mani Montazemi, RDMS Placenta
AFP = ??? Placenta Accreta
• G4 P3 • In patients with placenta previa, the risk of • Prior C-section accreta is 10-25% with 1 previous CS and • There is high association with placenta accreta 50% with 2 or more previous CS and elevated AFP • 1/22,000 pregnancies in the absence of previa
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
13 Risk Factors Placenta Accreta
• High morbidity from maternal bleeding • Prior Uterine resection • 90% require transfusions – septum revision, myomectomy • 7% mortality • 15% uterine rupture with percreta • In Vitro Fertilization – 13 fold increase • Plan and manage clinically for worst case scenario • Deliver at 34-35 weeks • Endometrial ablation – Complications from bleeding increase after 36 weeks • C-Section with hysterectomy • Radiation therapy • Smoking • Age
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Placenta Accreta
Increta Villi invade • Low implantation site, especially if offset into myometrium (cesarean scar) • Abnormal vascular spaces • Irregular placental / myometrial interface Percreta Villi invade to or through uterine serosa Bladder / Rectum
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
internal cervical os
Patient 2Low sac at 6 weeks gestation 4 prior cesarean sections Low sac at 6 weeks gestation 2 prior cesarean sections Placenta percreta placenta accreta next to area of scar
14 Placenta Previa without invasion of the myometrium
Intact bladder Uterine wall interface
Myometrium thickness
Mani Montazemi, RDMS Placenta
Placenta Accreta - Diagnostic Criteria Placenta Accreta - Diagnostic Criteria
No decidua between villi & myometrium • Multiple hypoechoic placental vascular lacunae – Swiss cheese appearance
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Placenta Accreta - Diagnostic Criteria Placenta Accreta
• Loss of hypoechoic myometrial zone • Usually occur low and at site of prior c-section • Thinning of subplacental hypoechoic zone < 1-2 mm • Use high resolution linear transducer for anterior placenta • Loss of bladder mucosal reflector • Focal exophitic masses
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
15 Placenta Accreta - Diagnostic Criteria
• Presence of color “tongues” of blood flow to the myometrial lakes
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Normal Placenta
Mani Montazemi, RDMS Placenta
Placenta Accreta
Mani Montazemi, RDMS Placenta
16 Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
27 weeks, 3 days
17 “In the 16 of 17 cases of percreta, the serosa-bladder interface hypervascularity was associated with vascularization of the entire placental width.”
Previa with No Accreta Placenta Percreta
Ultrasound Obstet Gynecol 2013; 41: 406-412 27 weeks, 3 days
Abruptio Placenta
• Subchorionic 81% – 91% before 20 weeks – 67% after 24 weeks
• Retroplacental 16% • Preplacental 4%
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Placental Abruption Abruptio Placenta
• Placental abruption causes a wide spectrum of • Acute hemorrhage sonographic findings that may be overlooked occasionally difficult to or misdiagnosed distinguish from the adjacent placenta • Look for placenta abruption in all gestations >20 wks with vaginal bleeding or tender uterus • Poor outcome when fetal bradycardia present
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
18 Sonographic Features of Abruptio Placenta Placental Abruption – False Positives
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Subchorionic Hemorrhage Subchorionic Hemorrhage
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Diagnostic Challenge
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Chorioangioma Placenta
19 Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Preplacental Hemorrhage
Hematoma is adjacent to, but does not compress the CI site Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Chorioangioma Chorioangioma
• Benign tumors of the placenta • Well-defined • Histology: blood vessels • Usually solitary but may be multiple (angiomatous) or cellular • Generally hypoechoic • Associated with MSAFP – Heterogeneous elevation • Hemorrhage • Infarction • Degeneration • Near cord insertion • Size usually stable throughout pregnancy
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
20 Chorioangioma Chorioangioma
• Fetal tachcardia and fetal distress may develop if there is great vascularity acting as an AVM
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Chorioangioma Placental Infarction
• Tumors < 5 cm are usually of no clinical • Focal lesion significance – ischemic necrosis of the placenta • Tumors > 5 cm may be associated with • Difficult to diagnosis sonographically unless polyhydramnios, premature labor, antepartum calcification hemorrhage, IUGR, hydrops and/or heart • Prognosis dependent upon failure extent of process
Mani Montazemi, RDMS Mani Montazemi, RDMS Placenta Placenta
Thank You
Mani Montazemi, RDMS Placenta
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