Intrauterine

- Hello, my name is Phil Perera,
and I'm the emergency ultrasound coordinator
at the New York Presbyterian Hospital in New York City.
And welcome to SoundBytes Cases.
In this module entitled Emergency OB/GYN Ultrasound: Part I,
we're going to focus entirely on the
ultrasound findings of intrauterine pregnancy.
Now patients with early pregnancy and vaginal bleeding
with or without abdominal pain
are frequently seen in the emergency department.
Luckily for us, emergency OB/GYN ultrasound
has evolved to be one of the most helpful
applications of sonography
in a busy emergency medicine practice.
So this module will be focused
primarily on the detection of intrauterine pregnancy
and we'll examine the ultrasound findings that define
a normal pregnancy for an emergency physician sonographer.
Before launching into the sonographic findings
of a normal intrauterine pregnancy,
let's take a moment to quickly review
the OB/GYN anatomy important for this application.
We see the uterus to the left and adnexa to the right.
Notice the areas of the uterus.
We see the lower cervix,
the intermediate body,
and the fundal region towards the top of the uterus.
Now, the fundal region is where we define
an intrauterine pregnancy to be located.
We see the area where the fallopian tube
enters into the uterus,
which is the interstitial region in a normal uterus
and the cornual region in a bicornuate uterus.
And this is where some variants of ectopics can implant.
Notice the areas of the fallopian tube to the right,
which we'll concentrate more on
with regard to ectopic pregnancy.
And we see the broad ligament there encasing
the fallopian tube and the ovary as seen to the right.
When taking care of a patient
who has vaginal bleeding in pregnancy,
there's four main classifications of diagnoses.
The first is a Threatened Abortion,
which is defined as the presence
of an intrauterine pregnancy with bleeding.
The second main classification
encompasses several different terms.
The terms that are commonly used are,
Incomplete Abortion,
Missed Abortion,
Blighted Ovum,
and Fetal Demise.
Basically, all of these mean the presence
of fetal membranes or parts,
without expected fetal growth or cardiac activity.
The third main classification is a Completed Abortion,
in which there is no further presence
of fetal membranes or parts,
and on examination, usually the cervical os will be closed.
The fourth main classification is the most dangerous,
is Ectopic Pregnancy.
Here's a table showing the structures in pregnancy
and about the time that they're seen on transvaginal
versus transabdominal sonography.
As we look in the Embryonic Structure column to the left,
we see the first structure that appears
is a gestational sac, seen on transvaginal sonography
at about 4.5 to 5 weeks,
and about a week later on transabdominal sonography.
The yolk sac is seen at about 5 to 5.5 weeks
on transvaginal sonography
and a week later on transabdominal sonography.
I have this circled in red,
as this is really the way we diagnose
an intrauterine pregnancy.
Then note the fetal pole is seen at about 5.5 to 6 weeks
on transvaginal sonography
and a week later on transabdominal sonography.
The last main finding, which is a fetal heart beat,
is seen at about six weeks on transvaginal sonography
and about at seven weeks on transabdominal sonography.
Another important concept for OB/GYN sonography,
is the correlation of the serum beta HCG
to the findings of a normal pregnancy.
As we see here for transvaginal sonography,
the discriminatory zone at which we will see
findings of an intrauterine pregnancy
are about 1,500 to 2,000 mIU.
For transabdominal sonography,
the discriminatory zone is about 6,500 mIU.
Now, this rule does not apply to ectopic pregnancies,
which secrete beta HCG at atypical levels
and are commonly seen with betas all over the map.
They can be seen with betas lower than 1,000
and as high as 30,000.
The first finding that will occur
during an intrauterine pregnancy
is going to be a gestational sac.
As we see here in the ultrasound picture to the right,
it's a small, round circle that's dark
or hypoechoic in relation to the rest of the uterus.
We actually see a gestational sac below that
that came out of a patient.
Notice that it has a translucent, membrane-type appearance.
Unfortunately, gestational sac
is not diagnostic of an intrauterine pregnancy,
as a pseudogestational sac of ectopic pregnancy
can be seen from hormonal stimulation.
As a general rule of emergency ultrasound,
is that visualization of a gestational sac
is not adequate to call an intrauterine pregnancy.
Here's two video clips showing the gestational sac.
Long Axis to the left,
and Short Axis to the right.
We see here a very small diameter gestational sac
in both of these orientations.
Unfortunately, this can be seen with a
pseudogestational sac of ectopic pregnancy.
So a small gestational sac, like this,
is in no way diagnostic of an intrauterine pregnancy
for the emergency physician sonographer.
Remember that the gestational sac is seen
at about 4.5 to 5 weeks on transvaginal sonography,
and about a week later on transabdominal sonography.
Here are the findings that we define
as indicative of an intrauterine pregnancy
for an emergency physician sonographer,
and that is the presence of a gestational sac
with a yolk sac inside.
As we see in the picture to the right,
the yolk sac has a circular-type appearance
that we call the Positive Cheerio Sign.
Let's just remember, gestational sac plus yolk sac
is indicative of intrauterine pregnancy.
However, bonus points are given
if you see a fetal pole with a heart beat
for confirmation of intrauterine pregnancy.
Here's a video clip showing a definitive
intrauterine pregnancy.
What we see here is a larger gestational sac
and as we look inside the gestational sac,
we see the positive yolk sac or Cheerio Sign.
Notice the circular yolk sac is seen
towards the inferior aspect of this gestational sac.
This would be diagnostic of an intrauterine pregnancy,
effectively ruling out an ectopic pregnancy
in the vast majority of patients.
Remember that the yolk sac is seen
at about 5 to 5.5 weeks on transvaginal sonography,
and about a week later on transabdominal sonography.
Here we see a pregnancy that is a bit further advanced.
Note we have a larger gestational sac,
that darker or hypoechoic area,
within the fundal region of the uterus,
and as we look inside the gestational sac,
we see the positive yolk sac or the Cheerio,
and looking just to the left of the yolk sac,
we see a tiny little fetal pole there.
Interestingly enough, as we zoomed up on that fetal pole,
we could make out the flicker of a heart beat.
So, a definitive intrauterine pregnancy.
Recall that the fetal pole is seen
at about 5.5 to 6 weeks on transvaginal sonography,
and about a week later on transabdominal sonography.
Here's a transvaginal short axis view
of a seven week intrautertine pregnancy.
We see the gestational sac here.
Notice that the gestational sac
is located in the center of the uterus
as seen here in short axis,
and there's a good amount of myometrial mantle
surrounding the gestational sac,
signifying a fundal location.
We see the positive Cheerio sign, or yolk sac,
to the upper right aspect of the gestational sac,
and right below, we see the fetal pole stretched out.
Notice the positive cardiac activity
as we scan back and forth through the fetal pole.
Here's another intrauterine pregnancy at about seven weeks,
again in the transvaginal short axis view.
We note the good amount of uterus
surrounding the gestational sac,
signifying the fundal location.
We see here the yolk sac or Cheerio sign,
and the fetal pole is stretched out below the yolk sac.
Notice the positive cardiac activity
within the fetal pole.
Now we see another very important finding here
on this ultrasound,
which is the amniotic membrane,
billowing out from around the fetal pole.
Eventually the amniotic membrane
will plaster down on the margins of the gestational sac
to form the amniotic cavity,
in which further growth of the fetus will occur.
Here's an interesting video clip
showing a twin pregnancy.
What we see here are two gestational sacs
signifying dichorionic twins,
and within each of the gestational sacs
we can see little fetal poles
with a flicker of heart beats.
Recall that fetal heart activity
is seen at about six weeks on transvaginal sonography
and about seven weeks on transabdominal sonography.
Here's an early second trimester pregnancy.
What we see here is the next Oscar De La Hoya.
Note the mean right hook on the baby here.
The important finding here is that
this is an intrauterine pregnancy
as we can define a good mantle of uterus
surrounding the pregnancy.
That's very important as there are some ectopics
that can grow to an advanced stage,
but they're discerned by a lack of uterus
around the pregnancy.
Here's another second trimester baby
and as I work in Northern Manhattan,
I refer to this baby as the Merengue baby.
Note the baby moving around fluidly within the amniotic sac.
A sure sign that this kid will grow up to be a slick dancer.
In conclusion, I'm glad I could share with you
this SoundBytes module
going over Emergency OB/GYN Ultrasound: Part I
of intrauterine pregnancy.
Emergency OB/GYN ultrasound is definitely
one of the most helpful sonographic applications
in a busy emergency medicine practice
and hopefully by going through the module
you now have an understanding
of the ultrasound findings diagnostic of a normal pregnancy.
I hope to see you back as we return
in OB/GYN Ultrasound Pregnancy Part 2,
focusing on further assessment of normal pregnancy
as well as looking further into
the ultrasound findings of an abnormal pregnancy.

Brightcove ID

5508114751001

https://youtube.com/watch?v=gv4q8ZB25JM

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Case: Intrauterine Pregnancy - Part 1

Case: Intrauterine Pregnancy - Part 1

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