Second and Third Trimester: Must Know Diagnoses

8/3/2014
2nd/3rd trimester scan
• Everything in the fetus
– Biometry
Second and Third Trimester: Must Know Diagnoses
Anne Kennedy MB, BCh
Professor of Radiology
Adjunct Professor of Obstetrics and Gynecology
Co‐Director Maternal Fetal Diagnostic Center
University of Utah Hospitals and Clinics
• Abdominal circumference
• Head circumference and biparietal diameter
• Femur length
• Placenta
• Fluid • Cervix “as clinically appropriate”
American Institute of Ultrasound in Medicine. AIUM practice guideline for the performance of
obstetric ultrasound examinations. J Ultrasound Med 2013; 32: 1083–1101. doi:10.7863/ultra.32.6.1083
Must Diagnose
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Vasa Previa
Morbidly Adherent Placenta
Abnormal 4 chamber heart
“Hydrocephalus”
Complications of monochorionicity
Risk factors for vasa previa
Placenta previa
Low‐lying placenta
Succenturiate lobe
Velamentous cord insertion
• Multiple gestation
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Reddy UM et al . Fetal Imaging . J Ultrasound Med. 2014 May;33(5):745‐57. Clinical photo courtesy of MJ Kamyar MD
Velamentous cord
Succenturiate Lobe
Normal placental cord insertion
Graphics reproduced courtesy of Amirsys Inc. Salt Lake City
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Vasa Previa: Velamentous cord
Velamentous cord
Clinical photo courtesy of MJ Kamyar MD
Vasa previa: Succenturiate lobe
Morbidly Adherent Placenta
• Prior cesarean section
– Placenta previa
• Prior uterine instrumentation
– Myomectomy
– Septoplasty
– D&C
US morbidly adherent placenta US normal anterior placenta
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Normal vs Abnormal
Normal vs Abnormal
Situs
Lack of formation of the normal decidual plate causes the placenta accreta spectrum. Chorionic villi extend into the myometrium. This “morbidly adherent placenta” fails to separate normally at the time of delivery.
• Situs solitus
–Normal
• Situs inversus
–Right left inversion
• Situs ambiguous
–Anything else
Bleeding can be catastrophic.
Cardiac Size
• HC:CC
– about 50%
• Area
– 3 hearts should fit in cross section of chest at 4C level
• Wall thickness
– Cardiomyopathy
• Hypertrophic • Dilated
• Diabetic Cardiac Axis
• Apex left
• Stomach and apex left for situs solitus
• Normal axis 30‐45o
– Line from spine to sternum
– Line along axis of ventricular septum
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Abnormal cardiac axis
• Chest mass
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Chamber symmetry
• Cardiac causes
CDH
CPAM
Sequestration
Teratoma
• Pulmonary agenesis – Chamber asymmetry
– Conotruncal malformations
– Heterotaxy syndromes
• Ectopia cordis
• Both ventricles apex forming
• RV > LV (1.6:1 by term)
• RA = LA
• IV septum ~ 2x IA septum
• Foramen ovale flap moves right to left
Which chamber is it?
• LV
– Smooth interior
– No septal valve attachment
• RV
RV
– Trabeculated interior with moderator band
– Tricuspid valve leaflet attaches to septum
LV
RA
LA
• LA
– Pulmonary veins connect • RA
– Systemic veins connect
Rib
Spine
RV
RV
LV
LV
RA
LA
Rib
Rib
Spine
Spine
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Heterotaxy with AVSD and Azygos Continuation of IVC
4 chamber checklist
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Axis
Situs
Size
Septum
AV Valve offset
• Symmetry
– Ventricles
• Chamber anatomy
– Atria
• Foramen ovale
• Vessels behind heart
• Aorta to LA
Pulmonary atresia Intact ventricular septum
Diagnoses you can make from the
4‐Chamber view
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Checklist for “watery” brains
• Midline
– Is there a falx?
– Is there a cavum?
• If there is a “cyst”?
– Midline/Lateral
• Cerebral hemispheres
– There or not?
– Normal or not?
– What about the ventricles?
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HLH
Pulmonary atresia
AVSD
Ebstein anomaly
Heterotaxy
TAPVR?
No Falx
Prosencephalon
Method of delivery
Timing of delivery
Prognosis
Recurrence risk • Aprosencephaly
• Atelencephaly
• Alobar holoprosencephaly
Mesencephalon
Rhombencephalon
• Size, shape, contour, lining
• Cerebellum
– Vermis?
– Cisterna magna/cyst?
– Torcular/tentorium?
Graphics reproduced with permission of Amirsys Inc. 5
8/3/2014
First trimester
Alobar Holoprosencephaly
Telencephalon
Diencephalon
Mesencephalon
Metencephalon
49 days
Myelencephalon
9 weeks TA
(bleeding , no fetal heart tones) Graphics reproduced with permission of Amirsys Inc. Falx: Yes
• Hydranencephaly
• Giant open lip schizencephaly
• Agenesis of corpus callosum with interhemispheric cyst
Bilateral giant open lip schizencephaly
Prognosis: Severe neurological impairment, seizure disorder
Coronal
Axial
Hydranencephaly
• Absent cerebral hemispheres • Early destruction of previously normal brain
• Falx present • Normal facies
AVID
Oh KY, Kennedy AM, Selden NR, McLean L, Sohaey R. Asymmetric ventriculomegaly, interhemispheric cyst, and dysgenesis of the corpus callosum (AVID): an imaging triad.
J Ultrasound Med. 2012 Nov;31(11):1811‐20. 6
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Twin twin transfusion syndrome
• Placental anastomoses result in arteriovenous shunt
Chorion
– 10‐20% monochorionic pregnancies
Y
Y
A
B
Amnions
• Donor (pump) twin high output
– sends blood to co‐twin instead of to placenta
– less blood to placenta = less coming back
– oligemia = decreased renal perfusion = oligohydramnios
• Recipient twin – gets “extra” blood from co‐twin= volume overload which may cause cardiomyopathy
– lots of blood to kidneys = lots of urine = polyhydramnios
TTTS
• Where is the membrane?
• Stuck twin
Graphic courtesy of Amirsys Inc, SLC, UT
TTTS
• ~10% monochorionic pregnancies
– 30% twins are monozygotic
• 70% of those are monochorionic
• Progressive
– 70‐100% mortality • if advanced, early presentation
– Most fetuses now expected to survive
• Laser coagulation of placental vessels is the treatment of choice
Society for Maternal‐Fetal Medicine, Simpson LL. Twin‐twin transfusion syndrome. Am J Obstet Gynecol. 2013 Jan;208(1):3‐18. Roberts D, Neilson JP, Kilby MD, Gates S. Interventions for the treatment of twin‐
twin transfusion syndrome. Cochrane Database Syst Rev. 2014 Jan 30;1:CD002073. TRAP
TRAP
• Placental anastomoses result in A‐A shunting
– ~1% monochorionic twins
• Pump twin high output
• Recipient twin – perfused with co‐twin’s deoxygenated blood – blood flow into fetus via arteries i.e. UA to internal iliacs to lower extremities
Graphic courtesy of Amirsys Inc, SLC, UT
Pagani G et al. Intrafetal laser treatment for twin reversed arterial perfusion sequence: cohort study and meta‐analysis. Ultrasound Obstet Gynecol. 2013 Jul;42(1):6‐14.
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DOUBLE TROUBLE
TTTS
TRAP
Combination of oligohydramnios in one sac and polyhydramnios in the other.
Check direction of umbilical artery flow in ANY abnormal twin
Must know
• Vasa previa
• Morbidly adherent placenta
• Normal 4 chamber
• Hydrocephalus
• Monochorionic twins
Why?
• Don’t kill a healthy baby
• Don’t kill a healthy mom
• CHD outcomes
• Pregnancy management
• Laser/RFA therapy
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