Gravid Uterus And Fetus Flashcards
For targeted imaging
Magnetic Resonance Imaging
Best imaging modality used routinely to evaluate gravid uterus.
Ultrasound
Comprehensive examination
Level I
Confirm abnormalities seen in level I scan
Targeted or specialized or imaging for fetal anomaly
Level II
Special transducer for the examination
Earliest detection of intrauterine pregnancy
Best method for imaging 1st trimester of pregnancy
Transvaginal
Requires urinary bladder to be full
Best method for imaging 2nd and 3rd trimester of pregnancy
Trans abdominal
Implantation of conceptus occurs usually in the fundal region of the uterus
between day 20-day 23 of menstrual cycle
Seen on endovaginal examination by 4-4.5 weeks after the last menstrual period.
Fertilized ovum implants into the decidualized endometrium.
Gestational sac burros into the endometrium.
Echogenic ring is seen eccentric to the linear interface of endometrial surfaces.
Intradecidual Sac Sign (IDDS)
Earliest sign seen on transabdominal examination
-two echogenic rings are seen within the endometrial cavity
Used to differentiate between intrauterine pregnancy and decidual cast of ectopic pregnancy
Double Decidual Sac Sign
Outer ring- decidual lining of the uterine cavity
Decidua parietalls
Inner ring- covering free margin of gestational sac
Decidua capsularis
Decidua basal is and chorlonic frondosum form the placenta
Decidua basalis
Presence of yolk sac within a gestational sac confirms
Intrauterine pregnancy
Yolk sac should be visible on transvaginal ultrasound by the time the mean sac diameter (MSD) of gestational sac is ?
8 mm
Non-visualization of yolk sac in presence of embryo demonstrable by endovaginal ultrasound is associated with ?
Intrauterine embryonic demise or missed abortion
First seen as a focal thickening of the yolk sac
Development of embryo
Embryo
Diamond ring sign
Earliest demonstration of Amninon
Double bleb formed by - yolk sac and amniotic sac
Double BLEB sign
Visualization of amnion without embryo is usually sign of ?
Intrauterine embryonic death
Becomes visible at 6 weeks when CRL of embryo is 2 mm
Amnion
Amnion, chorion, and embryo seen
Early signs of Pregnancy
Used for estimation of gestational age
Date early pregnancy before embryo is visible
Date age of gestation from 4-6 weeks
Measured in three orthogonal planes
(Length +AP+ transverse) / 3
Measured from top of the head to bottom of the torso of the visualized embryo or fetus
Crown-Rump length
More accurate indicator of gestational age than MSD
Crown-rump length
Affected by shape of fetal head
Maximum diameter of a transverse section of the fetal skull at the level of the parietal eminences
-level of paired thalami and cavum septum pellucidum
Measurement is taken from outer edge of near cranium to inner edge of far cranium
Biparietal Diameter
Rugby-football-shaped skull
Thalami view
Reflects growth of fetal head( together with BPD)
Measured on same axial plane as BPD
Perimeter measurement of fetal cranium
Head circumference (HC)
Length of the outer perimeter of fetal abdomen measured at the level of stomach and intrahepatic portion of the umbilical vein
Abdominal circumference (AC)
Placing the calipers on the outer borders of the widest part of the fetal abdomen at 90* to the APAD
Transverse abdominal
Slightly curved echogenic structure that produces an acoustic shadow
Femoral shaft
Spike on one end of the shaft
Not included in measurement
Femoral epiphysis
Uniform moderate echogenicity
Smooth chorionic plate without indentations
Grade 0
Subtle indentations of chorionic plate
Small, diffuse calcifications
Grade 1
Larger indentations along chorionic plate
Larger calcifications in a dot-dash configuration along the basilar plate
Grade 2
Complete indentations of chorionic plate through to the basilar plate creating cotyledons
Grade 3
Produced by fetal kidneys and removed by fetal swallowing & subsequent absorption by the fetal bowel
Amniotic fluid volume
Decreased fetal biometry (abdominal circumference)
Echogenic bowel, mild cardiomegaly and abnormal uteroplacental/fetal Doppler
Uteroplacental insufficiency
Maternal history of persistent vaginal loss & dampness
Amniotic membrane rupture
Bilateral renal agenesis, polycystic kidney disease, multi cystic Dysplasia and bladder outflow obstruction
Abnormal fetal Renal function
Physiological polydramnios
Only complication
Premature delivery due to uterine overdistention
Idiopathic polyhydramnios
Separate placentas
Separate chorlonic sacs
Separate amniotic sac
Always diamniotic dichorionic twins
Dizygotic twins
Most common
Each twins has its own chorionic and amniotic sacs
Dichorionic diamniotic twins
Triangular peak of chorion extending from the placenta into the inter-twin membrane
Twin-peak (lambda) sign
At the point of insertion of the membrane dividing the twin pair of placenta
Delta of lambda sign
