Obstetrics Flashcards
First trimester ?
Week 1 - 12
Second trimester?
Week 13 - 26
Third trimester ?
Week 27 - 42
Supine Hypotensive syndrome?
When the pregnant patient is placed in SUPINE, resulting in reduction of blood return to the heart resulting of the gravid uterus compressing the maternal IVC
Patients suffer from ; tachycardia, sweating, nausea, and pallor
These symptoms are alleviated when you assist the patient into DECUBITUS
TPAL?
Term
Premature
Abortions
Live births
(Should include the inquiry of previous pregnancies or fetal complications, diabetes, hypertension, infertility and the general health of other children at time of birth and currently)
Causes of first trimester bleeding ?
Ectopic pregnancy
Gestational Trophoblastic disease
Miscarriage
Blighted ovum
Embryonic demise
SubChorionic hemorrhage
Second trimester painful bleeding indicative of ?
Placenta ABRUPTION
Second trimester painless bleeding is indicative of ?
placenta PREVIA
Triple screen ?
Done between the weeks of 15 to 20
MSAFP, hCG, and estriol
Quadruple screen ?
Estriol/ hCG/ MSAFP
Additionally Inhibin - A
When are levels and NT measurement obtained ?
Weeks between 11 to 14
Levels ; hCG, estriol, and PAPP-A (pregnancy- associated plasma protein A)
And measuring the posterior fetal neck fold aka NT
Materni2Plus test?
Simple blood test that can be done early as 9 weeks ;
Reveal gender and highly accurate in detecting chromosomal anomalies such as ; trisomy 18, 21, and 13
DECREASED hCG levels indicative of ?
Abortion (misscarriage)
Anembryonic pregnancy
Ectopic pregnancy
Edwards Syndrome (18)
Turner syndrome /monosomy X (With hydrops)
Increased MSAFP levels indicative of?
Anencephaly
Cephalocele
Gastroschisis
Omphalocele
Patau / trisomy 13
Spina Bifida (meningocele or myelomeningocele)
Decreased MSFP indicative of ?
Downs Syndrome / trisomy 21
Edwards / trisomy 18
Turner Syndrome / Monosomy X
Decreased Estriol level indicative of ?
Down syndrome / trisomy 21
Edward syndrome / trisomy 18
Turner Syndrome/ monosomy x
First trimester measurements ?
Yolk sac
Gestational sac / MSD
CRL / Crown Rump Length
NT / translucency
Associated with pregnancy ?
Appendicitis (lower right quadrant pain)
Gallstones (right upper quadrant pain)
Hydronephrosis - with later term pregnancies (obstructing asymptomatic ureter)
(Back pain)
Abdominal circumference criteria?
TRANSVERSE
Fetal abdomen at the level of the umbilical vein and stomach
Also acceptable to be seen ;
Transverse thoracic spine, right adrenal gland, and gallbladder
Head circumference criteria ?
Measured from the outer perimeter of the skull at the level of the third ventricle, thalami and cavum septum pellucidum and falx cerebri
Head circumference criteria ?
Measured from the outer perimeter of the skull at the level of the third ventricle, thalami and cavum septum pellucidum and falx cerebri
(Taken at the same level as BPD)
From the outer to outer diameter
Typically more accurate since it’s independent from fetal head shape — providing a more consistent parameter for estimating gestational age
Femoral length criteria?
Sound beam is placed perpendicular to the long axis of the femoral shaft
Biparietal Diameter ?
Measure from the outer edge of the proximal skull to the inner edge of the distal skull (leading edge to leading edge)
Level of the thalamus, third ventricle, cavum septum pellucidum, and falx cerebri
Can be obtained from end of first trimester (week 13/14) in the axial plane
The cranial bones must be symmetric on both sides of the head
Biophysical point criteria ?
Thoracic movements (atleast one episode of stimulated fetal breathing lasting atleast 30 sec.)
Fetal movements (atleast three or more gross fetal body)
Fetal tone (atleast one flexion to extension of a limb or one hand opening/ closing)
Amniotic fluid (atleast one pocket of fluid measuring > 1 CM in vertical diameter in two perpendicular planes)
Nonstress Test (atleast two fetal heart accelerations)
(Each worth 2 points )
Fetal lie?
Either longitudinal or transverse
Fetal presentation?
Fetal body part closest to the internal os of the cervix
Cephalic is most common but baby can also present breech ;
Breech types?
Complete
Incomplete/ footling
Frank
Complete breech?
Fetal legs are flexed at the hips and there is flexion of the knees
Frank breech?
Fetal buttocks are closest to the cervix
Footling/ incomplete breech?
When there is extension of atleast one of the legs toward the cervix
The above image is of the gravid uterus of a 39-year-old patient who presented to the ultrasound department with a history of elevated MSAFP.
She states that the fetus appears to have been moving regularly, and she has had no pain or vaginal bleeding. What is the most likely diagnosis?
A.Spina bifida
B. Trisomy 18
C. Endometriosis
D. Anencephaly
Anencephaly
In the TPAL designation, the “L” refers to:
a. Living children
b. Lethal anomalies
c. Live births
d. Lost pregnancies
Live Births
All of the following are observed during a biophysical profile except:
a. Fetal tone
b. Thoracic movement
c. Fetal breathing
d. Fetal circulation
Fetal circulation
Which of the following would not be decreased in the presence of
Edwards syndrome?
a. Estriol
b. hCG
c. alpha-Fetoprotein
d. All would be decreased
All would be decreased
All of the following are produced by the placenta except:
a. alpha-Fetoprotein
b. hCG
c. PAPP-A
d. Inhibin A
AFP/ alpha fetoprotein (produced by the yolk sac and liver)
A myelomeningocele is associated with:
a. Down syndrome
b. Spina bifida
c. Edwards syndrome
d. Patau syndrome
Spina Bifida
The anechoic space along the posterior aspect of the fetal neck is the:
a. Nuchal fold
b. Nuchal cord
c. Nuchal translucency
d. Rhombencephalon
Nuchal Translucency
The premature separation of the placenta from the uterine wall before the birth of the fetus describes:
Placental ABRUPTION
Biophysical profile scoring is conducted:
a. Until the fetus cooperates
b. For 10 minutes
c. For 45 minutes
d. For 30 minutes
For 30 minutes
What is the fetal presentation when the fetal buttocks are closest to the cervix?
Frank breech
Which of the following would not typically produce an elevation in hCG?
a. Down syndrome
b. Anembryonic pregnancy
c. Triploidy
d. Molar pregnancy
Anembryonic pregnancy
The protein that is produced by the yolk sac, fetal gastrointestinal tract, and the fetal liver is:
AFP
Which of the following would be least likely associated with an elevation in MSAFP?
a. Anencephaly
b. Turner syndrome
c. Spina bifida
d. Myelomeningocele
Turners Syndrome
Trisomy 21 ?
Down’s syndrome
Trisomy 18 ?
Edwards syndrome
Trisomy 13?
Patau syndrome
Evolution of conceptus / zygote / blastocyst?
Mature ovum is released through ovulation / day 14, because the Graafian follicle ruptures and liberates the ovum into the distal portion of the tube (infundibulum)
The sperm and egg unite in the distal one - third of the fallopian tube (ampulla)
Conception usually occurs within the first 24 hours
The zygote formed transforms into the morula, which turns into the blastocyst which begins to implant into the decidualized endometrium at the uterine fundus
Blastocyst (inner/outer layer)?
Outer ;
Trophoblastic cells that produce hCG and eventually develops into the placenta and chorion (gestational sac)
Inner; develops into the embryo, amnion, umbilical cord, and the primary / secondary yolk sacs
Chorionic villi ?
Fingerlike projections of gestational tissue that attach to the decidualized endometrium
(allows transfer of nutrients from the mother to the fetus)
What occur during the 4th week of gestation?
The embryo is located between the yolk sac and the amnion
Primary yolk sac regresses
Chorionic and Amniotic membranes are formed
Outer ; chorionic sac
Inner ; amniotic sac
By the END of the 4th week ;
The secondary yolk sac becomes lodged between the chorion and amniotic membranes
Extraembryonic Coelom?
Aka chorionic cavity
Where the secondary yolk sac is located at the end of the fourth week of gestation
(Between the chorionic and amniotic membranes)
What occurs during the 4th week of embryo development ?
Alimentary Canal begins to form (foregut/ midgut/hindgut)
Neural tube begin to develop (fetal head and spine)
What occurs at 6 weeks of embryo development ?
All internal and external structures begin to develop
The obstacle of an inaccurate LMP being provided by the patient can be overcome by the following?
Referencing hCG levels in maternal circulation
Gestational sac AKA?
Chorionic sac
Lab test used to detect pregnancy ?
hCG
(Produced throughout pregnancy by the placenta)
Detected in maternal circulation early as 23 (days) menstrual/ gestational age
Earliest definitive sign of IUP ?
A gestational sac should be seen with transvaginal sonography with hCG levels between 1000 - 2000 mIU per mL
Average growth rate of the gestational sac?
1 mm per week
Ex. 5 weeks — > 5 mm gestational sac diameter / MSD
Normal hCG levels associated with normal IUP?
Doubles every 48 hours until it plateaus at the end of the first trimester and slowly decreases with advancing gestational age
Decreased levels of hCG compared to normal IUP indicates?
Ectopic pregnancy
Abortion/ miscarriage
Elevated levels of hCG compared to normal IUP indicates ?
Twin pregnancy
Complete Molar Pregnancy (significantly high levels of hCG)
First definitive sonographic finding of IUP?
Indentification of the gestational sac within the decidualized endometrium (thickened and echogenic)
Early gestational sac sonographic findings ?
First seen transabdominal by 5 weeks
Appearing as a small anechoic sphere within the decidualized endometrium
Growth rate ; 1mm/per day in early pregnancy
Intradecidual sign?
Small gestational sac in the uterine cavity surrounded by the thickened, echogenic endometrium
Double sac sign ?
Distinct appearance of the two layers of the DECIDUA separated by the anechoic fluid filled uterine cavity
Decidua CAPSULARIS/ PARIETALIS
Safe to assume that a round/ oval shaped fluid collection within the endometrium of a patient with a (+) pregnancy test and hCG levels above the discriminatory zone indicates?
Gestational sac
Chorionic Cavity ?
Space between the gestational sac and the amniotic sac
Location of the secondary yolk sac
Chorion Frondosum?
Decidualized tissue at the implantation site containing the chorionic villi
Fetal contribution of placenta
Fetal contribution of placenta ?
Chorionic frondosum
Chorion Laeve?
Portion of the chorion that does not contain chorionic villi
Decidua BASALIS?
Endometrial tissue at the implantation site
Maternal contribution of placenta
Maternal contribution of placenta ?
Decidua basalis
what is the earliest sonographic measurement obtained to date the pregnancy ?
MSD / mean sac diameter
(Relatively accurate form of dating but can only be used until a fetal pole is recognizable (sonographically)
MSD obtained by ?
Dimension L x W x H (divided by 3)
(By adding 30 to MSD (in milimeters) sonographer can estimate the gestational age in days)
Signs of potential pregnancy failure ?
Irregular shaped gestational sac
MSD > 25 mm that does not contain a fetal pole
First structure seen within the gestational sac ?
Secondary yolk sac
(Round, anechoic circular structure surrounded by a thin echogenic rim)
Located within the chorionic cavity (between the chorion and amnion)
Yolk sac is connected to the embryo via?
Vitelline duct / omphalomesenteric duct
Gestational sac consists of ?
Chorionic cavity
Amniotic cavity
Chorionic cavity ?
Between the amnion and the chorion
Fluid and the yolk sac is located
Amniotic cavity contents ?
Embryo and amniotic fluid
Amniotic membrane / amnion appearance ?
can be seen within the gestational sac as a thin, echogenic line loosely surrounding the embryo
When do the chorion and amnion typically fuse ?
Around the middle of the first trimester, by the 16th gestational week
Sonographic findings of embryo at 5 / 6 weeks ?
By 6 weeks with TV the embryo can be seen within the amniotic cavity adjacent to the yolk sac
Fetal heart motion is assessed with motion mode (M- mode) (between 5 to 6 weeks)
When the embryo is 4 mm , with definitive evidence by 5 mm
Growth rate; 1 mm/ per day
Often the first sonographic sign of a eminent embryologic demise ?
< 90 bpm
Bradycardia
Associated with a poor prognosis
Heart rate between 5 to 6 weeks ?
100 to 110 bpm
By 9 weeks heart rate should increase to?
150 bpm
From the second trimester to term heart rate ?
Around 150 bpm
Most accurate sonographic measurement of pregnancy ?
CRL / crown rump length
(From when the fetal pole is identified, till the second trimester and biometric measurements can be obtained )
Sonographic findings of embryo (7 to 8 weeks)?
Fetal limbs buds can be identified
Fetal head is larger than the body (bobble head)
Rhombencephalon may be seen within the fetal head as a round cystic structure
Stomach may also be seen in the upper abdomen at 8 weeks
Physical bowel herniation begins at 8 weeks — returns to the abdomen by 12 weeks
Physiological bowel herniation / migration occurs ?
Week 8 to 12
(If the midgut doesn’t not return into the abdomen by 12 weeks, follow up examination is warranted)
Fetus sonographic findings at the end of the first trimester ?
Fetal head ; within the lateral ventricles —> choroid plexus and seen separating the cerebral hemispheres ; falx cerebri
Fetal limbs more readily identified
Fetal movement
Fetal stomach
Urinary bladder
Umbilical cord
Spine
Developing placenta may be noted
With TV sonography the kidneys can be seen early as ?
13 to 14 weeks
Fetal abnormalities that can be detected at the end of the first trimester with TV - high resolution ?
Neural tube defects
Abdominal wall defects
Cardiac defects
Facial features (cleft palate)
Nasal bone
Disorders of the extremities
Placenta sonographic findings ?
May be seen developing by the end of the first trimester
Appears as a well defined, crescent shaped homogeneous mass of tissue along the margins of the gestational sac
Umbilical cord sonographic findings ?
Seen during the end of the first trimester as a tortuous structure connecting the fetus to the developing placenta
NT?
Vital part of early first trimester screening
Thin membrane along the posterior aspect of the fetal neck
Most common abnormalities associated with increased NT?
Trisomy 21
Trisomy 18
Turner’s syndrome
Congestive heart failure
Obtaining NT criteria ?
The margins of the NT edges must be clear enough for proper placement of the calipers.
2. The fetus must be in the midsagittal plane.
3. The image must be magnified so that it is filled by the fetal head, neck, and upper thorax.
4. The fetal neck must be in a neutral position, not flexed and not hyperextended.
5. The amnion must be seen as separate from the NT line.
6. The (+) calipers on the ultrasound must be used to perform the NT measurement.
7. Electronic calipers must be placed on the inner borders of the nuchal space with none of the horizontal crossbar itself protruding into the space.
8. The calipers must be placed perpendicular to the long axis of the fetus.
9. The measurement must be obtained at the widest space of the NT.
NT obtaining timeframe ?
Optimally measured between 11 to 13 weeks / 6 days
CRL measuring between ; 45 to 84 mm
NT dimmension should not exceed from week 11 to 13 and 6 days gestation?
< 3 mm
Associated early sonographic sign of Down syndrome ?
Increased NT
Absent/ hypoplastic nasal bone
Equal sign?
Appearance of a normal fetal bone and overlying nasal skin
Corpus Luteum Cyst associated with pregnancy ?
Most common functional cyst associated with pregnancy
Will usually enlarge due to high level of hCG exposure from the pregnancy and reach sizes up to 2 to 3 cm but can reach sizes up to 10 cm
Appears as a simple cyst, complex cyst with hemorrhagic components, as a hypoechoic mass or have a thick echogenic rim that displays increased colour doppler signal with low resistance spectral doppler waveform present
Could be confused for an ectopic pregnancy
Most common causes of pelvic pain with a positive pregnancy ?
Ectopic pregnancy
Ectopic pregnancy / EUP?
Pregnancy located anywhere other than the uterine or endometrial cavity (most commonly the fallopian tube)
Most common cause of pelvic pain with a positive pregnancy test
May lead to pregnancy loss, and in some cases even death
Ectopic pregnancy associations ?
ART
Fallopian tube scarring (essure device/ surgery)
PID ‘
Most common region for ectopic pregnancy?
Fallopian tube — ampulla segment
(Also can implant in the following areas :
isthmus of the tube, the fimbria, abdomen, interstitial portion of the fallopian tube (cornu of the uterus), ovary, and cervix,)
Increased risk of heterotopic pregnancy associated with ?
ART
Contributing factors to ectopic pregnancy ?
Previous ectopic pregnancy
Previous tubal surgery (including tubal sterilization)
History of pelvic inflammatory disease (salpingitis)
Undergoing infertility treatment / ART
Previous or present use of an intrauterine contraceptive device / IUD
Multiparity
Advanced maternal age
Classical clinical triad of Ectopic pregnancy ?
Pain
Vaginal bleeding
Palpable abdominal / pelvic mass
Also may present with ;
Amenorrhea
Low hCG compared to normal IUP levels
Shoulder pain ( secondary to intraperitoneal hemorrhage with diaphragmatic irritation)
Low hematocrit (with rupture)
Cervical motion tenderness
Sonographic findings of ectopic pregnancy ?
Extrauterine gestational sac with fetus and yolk sac seen
Adnexal ring sign, complete adnexal mass located between the uterus and ovary
Also a large amount of fluid located in the
Pelvis/POD / posterior cul de sac and Morrison pouch
Pseudogestational sac and a poorly decidualized endometrium
Most severe case of ectopic pregnancy ?
Interstitial
Due to the high vascular content
Prone to excessive hemorrhage
Potentially life threatening because the pregnancy may progress normally until spontaneous rupture occurs
Gestational sac that is located in the superolateral portion of the uterus
( Assess for thinning of the myometrium surrounding the gestation that is located within the interstitial portion of the fallopian tube )
Treatment of ectopic pregnancy ?
Methotrexate
Administered either by ;
Injected into the EUP (sonographic guidance) or taken intramuscularly
When they are confined to the fallopian tube and size less than < 4 /5 cm
Gestational Trophoblastic Disease ?
Complete molar pregnancy or
partial incomplete molar pregnancy
Group of disorders that result from abnormal combination of male/ female gametes
GTD results in excessive growth of the trophoblastic cells, which produces hCG — which results in markedly high hCG levels and theca lutein cysts likely developing
(Typically benign but does have a malignant potential)
Most common type of gestation trophoblastic disease?
Complete / molar pregnancy
Sonographic findings of gestational trophoblastic disease (complete molar pregnancy) ?
Complex mass within the uterus
Color doppler may reveal hypervascularity around the mass but not within it
Vesicular snowstorm appearance secondary to placenta enlargement
Multiple, variable - sized cysts replacing the placenta tissue (hydropic chorionic villi)
Bilateral ovarian theca lutein cysts (large and multiloculated masses)
Sonographic findings of partial molar pregnancy ?
Complex mass within the uterus partially filling the uterine cavity adjacent to the gestational sac
Vesicular snowstorm appearance secondary to placenta enlargement
Multiple variable sized cysts replacing the placenta tissue (hydropic chorionic villi)
Triploid fetus
Symptoms of gestational trophoblastic disease?
Hyperemesis gravidarum
Markedly high hcg level (> 100 000 mIU per mL) leading to bilateral theca lutein cysts developing
Heavy vaginal bleeding with possible passageway of grapelike molar clusters
Hypertension
Uterine enlargement
Even hyperthyroidism and possibly preeclampsia or eclampsia
Diagnosis of blighted ovum / anembryonic gestation ?
No evidence of a fetal pole or yolk sac within the gestational sac
Often the gestational sac is irregular shaped with a poor decidual reaction
Patients often have lower hCG levels, vaginal bleeding and reduction in pregnancy symptoms
Embryonic demise / poor outcome associated with the following ?
Heart rate less < 90 bpm (bradycardia)
Not seeing heart activity within a 5mm fetal pole with endovaginal sonography
Yolk sac that is echogenic, enlarged, distorted, and/ or calcified
cause of embryonic demise?
May be idiopathic or linked with chromosomal abnormalities
Sonographic finding of impending fetal demise ?
Present small for dates and typically have vaginal bleeding with a closed cervix.
Gestational sac small compared to the CRL length
Yolk sac diameter ?
< 7 mm
Termination of a pregnancy before viability is termed ?
Miscarriage or Abortion
Abortion categories ?
Threatened
Complete
Incomplete
Missed
Inevitable
Septic
Elective
Abortion / miscarriage symptoms ?
Vaginal bleeding
Pelvic cramping
Passage of products of conception
Low hCG levels compared to IUP
First trimester miscarriages have been linked with ?
Idiopathic or
Ovarian abnormalities
Aneuploid fetus
Maternal infections
Physical abuse
Trauma
Drug abuse
Maternal endocrine abnormalities
Anatomic factors
Threatened abortion ?
Vaginal bleeding before 20 weeks
Closed cervical os
Low fetal heart rate
Complete / spontaneous abortion ?
All products of conception expelled
No intrauterine products of conception identified
Prominent endometrium (may contain hemorrhage)
Incomplete abortion ?
Parts of product of conception expelled
Thickened and irregular endometrium
Enlarged uterus
Missed abortion ?
Fetal demise with retained fetus
No detectable feta rate motion detected
Abnormal fetal shape
Inevitable abortion?
Vaginal bleeding with dilated cervix
Low lying gestational sac
Open internal os of cervix
SubChorionic hemorrhage ?
Essentially a bleed between the endometrium and gestational sac
Result from implantation of fertilized ovum into the uterus with subsequent low pressure bleeding / spotting and possible cramping
SubChorionic hemorrhage sonographic findings ?
Crescent anechoic/ hypoechoic/ echogenic shaped area adjacent to the gestational sac (echogenicity depends on age of hemorrhage)
May resemble a second gestational sac
Large subchorionic bleeds have been associated with ?
Miscarriage and stillbirth
Acute SubChorionic hemorrhage appearance ?
Recent bleeds are hyperechoic or isoechoic to the placenta
Chronic subchorionic hemorrhage appearance?
(Long standing)
Anechoic or hypoechoic
Sonographic findings of fibroids associated with pregnancy ?
Common benign pelvic mass that can often be identified during the first trimester exam
Since they are stimulated by estrogen — they might increase in size with the ongoing pregnancy
Increased risk associated with early pregnancy failure, especially with multiple gestations
Cervical and lower segment types are most relevant since they might pose a dilemma at delivery
Needs to be differentiated from myometrial contractions
Myometrial contractions sonographic findings ?
Smooth muscle contraction
Appears like a myometrial fibroid but doesn’t consistently alter the shape of the uterine myometrium like a fibroid does
They typically resolve within 20 to 30 minutes
Symptoms of fibroids associated with pregnancy ?
Positive pregnancy test
Pelvic pressure
Menorrhagia
Palpable pelvic mass
Enlarged and bulky uterus (if multiple)
Urinary frequency
Dysuria
Constipation
IUD associated with pregnancy ?
Failed IUD / ineffective
Seen as an echogenic structure within the uterine cavity adjacent to the gestational sac
May produce shadowing
With a normal pregnancy, the first structure noted within the decidualized endometrium is the?
Chorionic Sac
Sonographically, a normal-appearing 7-week IUP is identified. Within the adnexa, an ovarian cystic structure with a thick, hyperechoic rim is also discovered. What does this ovarian mass most likely represent?
a. Theca lutein cyst
b. Corpus luteum cyst
c. Corpus albicans
d. Ectopic pregnancy
Corpus Luteum cyst
The first sonographically identifiable sign of pregnancy is the:
a. Amnion
b. Yolk sac
c. Decidual reaction
d. Chorionic cavity
Decidual Reaction
The first structure noted within the gestational sac is the:
a. Yolk sac
b. Embryo
c. Decidual reaction
d. Chorionic sac
Yolk Sac
What hormone maintains the corpus luteum during pregnancy?
a. Estrogen
b. Progesterone
c. Follicle-stimulating hormone
d. hCG
hCG / human chorionic gonadotropin
All of the following are clinical features of an ectopic pregnancy except:
a. Pain
b. Vaginal bleeding
c. Shoulder pain
d. Adnexal ring
Adnexal ring
In the early gestation, where is the secondary yolk sac located?
a. Chorionic cavity
b. Base of the umbilical cord
c. Embryonic cranium
d. Amniotic cavity
Chorionic Cavity
All of the following are sonographic findings consistent with ectopic pregnancy except:
a. Decidual thickening
b. Complex free fluid within the pelvis
c. Bilateral, multiloculated ovarian cysts
d. Complex adnexal mass separate from the ipsilateral ovary
Bilateral multiloculated ovarian cysts (theca lutein) so can’t be associated with EUP
Malignant forms of gestational trophoblastic disease ?
Choriocarcinoma and invasive mole
Which of the following is the most likely metastatic location for GTD?
a. Rectum
b. Pancreas
c. Spleen
d. Lungs
Lungs
(Liver and spleen as well)
All of the following are clinical findings consistent with a complete molar pregnancy except:
a. Vaginal bleeding
b. Hypertension
c. Uterine enlargement
d. Small for dates
Small for dates
All of the following may be sonographic findings in the presence of an ectopic pregnancy except:
a. Pseudogestational sac
b. Corpus luteum cyst
c. Adnexal ring
d. Low beta-hCG
Low beta hCG
Initially the brain is divided into three primary vesicles ?
Forebrain (prosencephalon)
Midbrain (mesencephalon)
Hindbrain
(rhombencephalon)
(May be seen within the fetal cranium during the end of the first trimester)
Eight cranial bones ?
Parietal (superior / lateral)
Temporal (inferior / lateral)
Frontal (anterior)
Occipital (posterior)
Sphenoid (lateral)
Ethmoid (anterior (between orbits)
Craniosynostosis ?
Premature fusion of the sutures
Leads to an irregular shaped head
Spaces that exist between the forming fetal bones ?
Fontanelles/ soft spots
Can be used as acoustic windows to assess for infantile intracranial hemorrhage or suspected brain anomalies
Bregma?
Anterior Fontanel when completely filled with bone
posterior skull suture filled with bone ?
Lambda
Foramen Magnum ?
Opening at the base of the cranium where the spinal cord travels through
Brain can be divided into?
Cerebrum
Cerebellum
Cerebrum ?
Right / Left hemispheres
Largest part of the brain
Contains multiple sulci and gyri
Cerebral lobes?
Frontal
(2) Temporal
(2) Parietal
Occipital
Cerebrum is divided into a right and left hemisphere by ?
Interhemispheric fissure
Appears as a echogenic linear formation coursing through the midline
Cerebral hemispheres are linked in the midline by the corpus callosum
Cerebral hemispheres are linked in the midline by the ?
Corpus callosum
Corpus callosum ?
Thick echogenic band of tissue within the midline that provides communication and connection between the right and left halves of the brain
Should be completely intact between 18 - 20 weeks
Meninges layers (O/I)?
Outermost; dura mater
Middle; arachnoid membrane
Innermost ; pia mater
Meninges ?
Three protective layers that cover the brain and spinal cord and comprised of three layers ;
Dura Mater (outer)
Arachnoid membrane
Pia Mater (inner)
Cavum Septum Pellucidum ?
Midline anterior portion of brain between the frontal horns and lateral ventricles
(Does NOT communicate with the lateral ventricles)
Appears as a anechoic box shaped structure in axial / trv plane
Typically seen between 18 to 37 weeks
Closure of this structure typically occurs before birth or shortly after
Absence of the Cavum Septum Pellucidum associated with ?
Multiples cerebral malformations, including ACC / Agenesis of the Corpus Callosum
Thalamus ?
Vital
Two lobes are located on both sides of the third ventricle
Can NOT be confused for the cerebral peduncles which are more inferiorly positioned in the brain
Mass intermedia ?
Aka Interthalmic adhesion
Passes through the third ventricle to connect the two lobes of the thalamus
Third ventricle passes through
Lateral ventricles location ?
Located on both sides of the falx cerebri within the cerebral hemispheres
AKA ; right/ left
Consists of ;
Frontal , Temporal, and Occipital horns
Ventricles of the brain function ?
Provide cushioning for the brain
Choroid Plexus?
Located within the atria of both lateral ventricles
Mass of cells responsible for the production of CSF
Each lateral ventricle communicates with the third ventricle via ?
Foramen of Monro
(Located between the two lobes of the thalamus)
Third ventricle ?
Contains mass intermedia / interthalamic adhesion
Each lateral ventricle communicates with the third ventricle
Only seen when enlarged or surrounded by CSF
What connects the third and fourth ventricle inferiorly ?
Aqueduct of Sylvius / cerebral aqueduct
(Long , tube - like structure)
Fourth ventricle ?
Located anterior to the cerebellum within the midline of the brain
Has 3 apertures for CSF to travel through
Lateral ; foramina of Luschka
Foramina of Luschka ?
Two lateral apertures of the fourth ventricle located within the midline, anterior to the cerebellum
Purpose is to allow CSF to travel from the fourth ventricle to the subarachnoid space around the brain
Which aperture of the Foramen of Luschka allows CSF to pass from the fourth ventricle to the cisterna magna and subarachnoid space ?
Foramen of Magendie
CSF pathway ?
Greater part of CSF is produced by the cells of the choroid plexus
(Located within the trigone of the lateral ventricles)
Moves from the lateral ventricles to the fourth ventricle via the foramen of Monro
From the third ventricle to fourth ventricle via aqueduct of sylvius
Once in the fourth ventricle, the fluid can exit either through the lateral or median aperture
(Foramen of Luschka / Lateral )
(Foramen of Magendie /median)
Responsible for reabsorption of CSF into the venous system ?
Arachnoid villi
(Occurs at the superior sagittal sinus) which is located along the superior surface of the cerebrum within its midline
Cisterna Magna ?
Located posterior fossa of the cranium
Appears as a posterior fluid filled space
Posterior to the cerebellum between the cerebellar vermis and interior surface of the occipital bone
Common finding to see small septations within the cisterna magna
Cerebellum?
Located in the posterior fossa in the cranium
Consists ; left / right side
Appears dumbbell shaped anterior to the cisterna magna
Distorted cerebellum shape is associated with?
Spina bidfia
Arnold Chiari Malformations
OFD ?
Occipital Frontal
diameter
Obtained at the same level as the HC and BPD
Caliper is placed from the middle of the anterior frontal bone in the middle of the occipital bone
Brachycephaly ?
Rounder /short / wide head shape
Cephalic index ; > 85
Dolichocephalic / Scaphocephaly ?
Enlongated and narrow head shape
Cephalic Index ; < 75
Cephalic Index formula ?
BPD / OFD x 100 = CI
(Used to indicate the shape of the fetal head)
Lateral ventricle measurement ?
In TRV and the level of the atrium
< 10 mm
Lateral ventricle measurement indicating that ventriculomegaly is present?
> 10 mm
Lemon shape fetal head associated with ?
Chiari II malformation
strawberry head shape associated with?
Trisomy 18 / Edwards syndrome
Cloverleaf shape skull is associated with?
Thanatophoric Dysplasia
Microcephaly is associated with?
TORCH infections
Trisomy 13/ Patau
Trisomy 18/ Edward
Meckel Gruber Syndrome
Fetal Alcohol syndrome
Macrocephaly is associated with?
Hydrocephalus
Hydranencephaly
Intracranial Tumor
Familial inheritance
Beckwith - Wiedemann syndrome
associated with brachycephaly ?
Craniosynostosis
Trisomy 21 / Down syndrome
Trisomy 18 / edward syndrome
Dolicocephaly is associated with?
Craniosynostosis
Transcerebellar measurement ?
Growth rate from 14 to 21 weeks —
1 mm / per week
Ex. 16 week fetus with 16 mm cerebellum
Measured in the transverse plane at the same level of the cisterna magna and thalamus
Depth of the cisterna magna ?
NOT measure more < 10 mm deep
Less < 2 mm in the transcerebellar plane
Consistent with mega cisterna magna and Dandy - Walker complex ?
Cistern magna deeper than > 10 mm
Measurement of transcerebellar ( < less than 2 mm ) is worrisome of ?
Arnold Chiari II malformation
Hydrocephalus ?
Refers to dilation of the ventricular system caused by an increased volume of CSF, resulting in increased intraventricular pressure
Caused by obstruction to the flow of CSF
May be caused by chromosomal aberration and intrauterine infections
Can either be classified as mild/ moderate/ or severe
Communicating or Noncommunicating types
Ventriculomegaly?
Abnormal enlargement of the ventricles
Most common cranial abnormality
> 10 mm atrial diameter measurement
Dangling cord sign
Most common cranial abnormality ?
Ventriculomegaly
Dangling Cord sign ?
VENTRICULOMEGALY
Describes the sonographic appearance of the choroid plexus “ hanging” and surrounded by CSF, within the dilated lateral ventricle
Noncommunicating Hydrocephalus ?
Obstruction level is located WITHIN the ventricular system
Communicating Hydrocephalus ?
Obstruction lies OUTSIDE the ventricular system
Aqueductal Stenosis ?
Most common cause of hydrocephalus in utero
Involves the aqueduct of Sylvius (located between the third and fourth ventricle) may be narrowed, hence preventing the flow of CSF
Causes the third ventricle and both the lateral ventricles to expand,
with the fourth ventricle remaining normal
Hydranencephaly ?
Fatal condition, most dying within a year of life
Entire cerebrum is replaced by a large sac containing CSF
Falx cerebri may be partially /completely absent, where as the brain stem and basal ganglia are maintained and surrounded by CSF
Thalamus may be seen, but there will be no cerebral cortex seen
Causes of hydranencephaly ?
Bilateral occlusion of the internal carotid arteries
Or
Intrauterine infections such as ;
Cytomegalovirus or toxoplasmosis
(Which BOTH lead to destruction of the cerebral hemispheres)
Hydranencephaly appearance ?
Seems to appear normal in the first trimester, and becomes more apparent by the second and third trimester
NO cerebral mantle is present
(Can be difficult to differentiate from severe ventriculomegaly and holoprosencephaly)
Holoprosencephaly ?
Alobar/ Semilobar/ Lobar
Midline brain anomaly that is associated with brain defects and atypical facial structures
50 - 70 % patients suffer as well from trisomy 13 / PATAU syndrome
Alobar Holoprosencephaly ?
Most SEVERE form, can be consistent with life
Cortex shape can either be ; pancake, ball, or cup
Alobar holoprosencephaly is diagnosed with what sonographic findings ?
Absence of the corpus callosum, CSP, third ventricle, Interhemispheric fissure, and falx cerebri
Horseshoe shaped monoventricle and the lobes of the thalamus are fused and more echogenic
The cerebellum and brain stem remain intact
Lobar Holoprosencephaly ?
Least severe form
Can be consistent with life, most patients suffer from severe mental retardation
There are varying degrees of fusion of midline structures