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The first 25 slides, exactly as they appear. The full deck has 184 content slides.
Radiology
The First-Trimester Fetal Anatomy Scan
Built from Obstetric Imaging
What’s inside
12 sections · 184 slides
Why we scan at 11 to 13 weeks
From a test for chromosomes to a look at the whole baby
- A scan with a job that changed
- Who fits inside the window
- Where it all started: fluid behind the neck
- Reading those four numbers
- Then a blood test changed the picture
- So why still measure NT?
- How the purpose shifted
- Why early anatomy is now possible
- The guidelines agree
- Eight regions, one sweep
Doing the scan to a protocol
A fixed order of views turns a look-around into an examination
- Why a written protocol wins
- Suggested first-trimester protocol: structures to examine
- Suggested first-trimester protocol: anomalies you may recognise
- Start where you already are: the CRL view
- One sagittal view of the whole fetus
- Two add-ons to the same view
Cranium and brain: the normal picture
The head is a third of the fetus, and the easiest place to start
- Why the head comes first
- What to check in the skull itself
- The metopic suture is your window
- Three basic planes for the fetal brain
- Midline landmarks on the sagittal view
- Intracranial translucency, in plain words
- Three axial slices of the head
- The butterfly sign
- The aqueduct of Sylvius
- Transvaginal axial views of the fetal head
- Transabdominal or transvaginal?
Cranium and brain: what can go wrong
Five defects that are within reach at 11 to 13 weeks
- Five brain problems you can catch early
- Open neural tube defects: the background
- Acrania and the anencephaly sequence
- Why it is harder than it sounds this early
- Acrania and anencephaly: three appearances
- The spectrum you will actually see
- Two extra clues
- When a band causes it
- Cephalocele: a hole with contents
- Large cephaloceles seen early
- The first question to ask
- Cephalocele with polycystic kidneys
- Working up a first-trimester cephalocele
- What a 35-case series showed
- Holoprosencephaly: the forebrain does not split
- Why those two numbers differ so much
- What alobar and semilobar HPE look like
- Alobar holoprosencephaly on axial views
- Face and chromosomes in HPE
- The posterior fossa: a recent addition
- A warning before you call it abnormal
- Posterior fossa cyst: what to look for
- Posterior fossa cyst in three fetuses
- What a posterior fossa cyst means
- Ventriculomegaly this early is rare
- Judging it without normal ranges
- Ventriculomegaly at 13 weeks
- The largest series so far
- Why the ratio may matter later
The face
Already in every scan, yet clefts were being missed
- The face is already part of screening
- The evidence that clefts were missed
- Why the profile view alone fails
- Normal fetal face: sagittal and coronal views
- The retronasal triangle
- Midfacial hypoplasia
- Cleft lip and palate on the profile
- Cleft lip and palate on early scans
- The coronal route to the primary palate
- Reaching the secondary palate
- Two markers, used together
- The superimposed line
- Micrognathia: a small chin
- Severe micrognathia and agnathia
- Two ways to make it less subjective
- Eyes and orbits: be realistic
- Hypotelorism, proboscis and a single ventricle
- Cyclopia, proboscis and cataract
The neck
Where the NT is measured, and where lymph goes wrong
- Why the back of the neck rules
- What can actually be diagnosed here early
- Nuchal edema is a different word
- Massive nuchal edema
- Cystic hygroma colli
- Cystic hygroma of the neck
- What travels with a cystic hygroma
- What happens afterwards
- Is a hygroma just a very thick NT?
- Distended jugular lymphatic sacs
- Distended jugular lymphatic sacs
The spine
The head often gives the diagnosis before the back does
- When the spine becomes visible
- Three planes, three different jobs
- How to image the fetal spine
- Reading the normal sagittal spine
- Abnormal curvature and hemivertebra
- When the curvature is severe
- Body-stalk anomaly at 12 weeks
- Spina bifida: the head tells the story
- Why an open spine changes the head
- One unusual combination
- The first-trimester head signs
- First-Trimester Sonographic Marker for Open Spina Bifida
- First-Trimester Sonographic Marker for Open Spina Bifida (continued)
- Published markers for early open spina bifida
- Reading that marker list
- Finding the spinal lesion itself
- Open spina bifida: head and spine findings
- What follows the diagnosis
- Short spine and segmental agenesis
The thorax
Heart, lungs, ribs and the sheet of muscle underneath
- What the chest survey covers
- Bones of the fetal chest
- The heart: what is realistic at this stage
- A workable order for the heart
- Colour Doppler views of the early fetal heart
- Why the heart deserves the effort
- The lungs when they are normal
- Bilateral pleural effusions
- Other dark spaces in the chest
- Large left thoracic cyst
- What the sagittal chest view proves
- Thoracoabdominal ectopia cordis
- The diaphragm between lung and liver
- Congenital diaphragmatic hernia
- Left congenital diaphragmatic hernia
- The right-sided version is harder
- When CDH is missed early
- What an early CDH diagnosis triggers
The abdomen and its wall
Where the cord goes in tells you most of what you need
- What the abdominal survey covers
- Normal thoracoabdominal outline and cord insertion
- Two dark structures, and no more
- Stomach and bladder in the normal abdomen
- What a missing or misplaced stomach means
- Bladder and umbilical vein
- Abdominal wall defects start at the cord
- The trap before 12 weeks
- Physiologic midgut hernia and its resolution
- Telling the two wall defects apart
- Omphalocele: what it is
- Omphalocele in two aneuploid fetuses
- Large liver-containing omphalocele
- Gastroschisis: what it is
- Gastroschisis: free-floating bowel
- Why gastroschisis still needs watching
- Body-stalk anomaly as a wall defect
- Ectopia cordis and a naming correction
- Findings that are abnormal at any gestation
- Large abdominal cyst beside the bladder
- What to do about an abdominal cyst
The urogenital tract and genitals
Kidneys, bladder, and the one measurement that changes everything
- Fluid volume does not reassure you here
- Finding the kidneys
- Kidneys, adrenals and renal arteries
- Adrenals, ureters and bladder
- Bladder and umbilical arteries on colour Doppler
- Megacystis: the definition
- Megacystis: size decides the story
- Severe megacystis and obstruction
- Severe megacystis with a dilated posterior urethra
- Mild megacystis can resolve
- Two other causes of a big bladder
- Mild megacystis with an umbilical cord cyst
- Polycystic kidneys and fetal sex
- Genital tubercle in male and female fetuses
The limbs
Three segments, four limbs, and one honest study
- What the guidelines now ask for
- Fetal upper limbs in the first trimester
- What limb defects are actually found
Bringing it together
What to carry out of this deck and into the scan room
- The scan changed jobs
- Protocol beats improvisation
- The head does most of the work
- Two questions for every abnormal finding
- Know what this scan cannot do
- References
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- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition