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Radiology
Nuchal Translucency
Built from Obstetric Imaging
What’s inside
8 sections · 98 slides
Overview
- What this deck covers
What nuchal translucency is
A normal finding first, an abnormal one only past a threshold
- Start with the picture, not the term
- How the finding was pieced together
- The formal definition
- What counts as too thick
- Nuchal translucency measured at 13 weeks
- Three ways to express an age-adjusted result
- How one measurement becomes a risk number
- Reading the risk arithmetic
Why a thick nuchal translucency matters
One measurement, a wide range of conditions behind it
- A powerful marker for Down syndrome
- Adding blood markers sharpens it
- 63–77%
- Not a trisomy 21 test only
- Extra chromosome 21 on a karyotype
- Birth defects that also thicken the nape
- Genetics beyond a chromosome count
- How much extra sequencing actually finds
- Risk climbs with every extra millimetre
- Chance of aneuploidy by measured thickness
- When the chromosomes are normal
- Thickened nuchal fluid at 11 weeks
Why the fluid collects
Several different roads to the same picture on the screen
- One picture, many causes
- Proposed routes to the same puddle
- The skin and the drainage explanations
- The heart explanation
- The skeletal dysplasia explanation
Measuring it properly
A number used like a laboratory value has to be produced like one
- Why technique is the whole story
- Who scans, and by which route
- The window when it can be done
- Crown-rump length sets the gestational age
- Proving the slice is truly side-on
- Reading those landmarks
- Neck position changes the number
- Do not mistake the amnion for skin
- Magnification and caliper rules
- Repeat, and do not give up early
- When the cord loops around the neck
- Good versus poor nuchal translucency technique
- The image a good protocol produces
- The same measurement done badly
- What the two panels teach
- How programmes keep the number honest
- The two training programmes
- Monitoring never stops
- A programme that has now closed
Cystic hygroma or thick nuchal translucency
A long-running argument that may matter less than it seems
- Two labels for the same neck
- How the FASTER trial defined a cystic hygroma
- Septated cystic hygroma at 12 weeks
- Septations seen across the neck
- What the FASTER cystic hygroma cohort showed
- The Fetal Medicine Foundation view
- Read the outcome table alongside both views
- Fetal Outcomes Based on Presence of Septated Cystic Hygroma or Enlarged Nuchal Translucency
- Outcome comparison as printed in the book
- Why the argument may not matter
- What happens to these pregnancies
- So do not over-monitor the survivors
- Other things that look like a thick nape
- How to tell them apart
Where nuchal translucency fits today
A blood test changed the running order, not the value of looking
- The offer everyone should get
- How screening has moved on
- What the DNA blood test actually is
- What cfDNA is and is not validated for
- Two screening approaches side by side
- cfDNA is still only a screen
- Why a rarer condition gives more false alarms
- How the guidance bodies see it
- What the early scan gives you anyway
- Reading the added value
- If the measurement cannot be obtained
- How the test is chosen
- Read the screening options table this way
- Terminology Used to Describe Aneuploidy Screening Options
- Terminology Used to Describe Aneuploidy Screening Options (continued)
- Screening options as printed in the book
- The main advantage of screening early
- When the number is high enough to stop screening
- What to do after a thick nuchal translucency
- If she wants to avoid an invasive test
- Twins make blood-based screening harder
- Identical twins sharing one placenta
- Normal chromosomes, thick nuchal translucency
- The heart deserves its own scan
- But it is still a good referral trigger
- When the fluid does not go away
- What happens to the children afterwards
What to carry away
The message for the referring clinician and for the parents
- What the referring physician needs to know
- Only offer it if you can do it properly
- Where that leaves the scan
- Key points, part one
- Key points, part two
- References
- References (continued)
- References (continued)
- References (continued)
- References (continued)
- Suggested readings
- Obstetric Imaging: Fetal Diagnosis and Care, 2nd Edition