Learning objectives
To review one of the most important measurements performed on the first trimester ultrasound,
the nuchal translucency (NT),
and the main foetal anomalies associated with its increase.
Background
An increased NT has been strongly associated with many genetic,
cardiovascular and structural anomalies.
Is the sonographic appearance of the amount of nuchal fluid behind the cervical spine that can be identified and measured in virtually all fetuses between the 10th and 14th week of gestation.
Cystic hygromas are congenital malformations of the lymphatic system,
characterized by fluid filled lesions at sites of lymphatic–venous connections along the posterior neck and back,
and in which septations may develop.
Cystic hygroma may be considered a markedly increased...
Findings and procedure details
At our institution chorionic villus sampling and foetal echocardiogram are provided when a nuchal translucency greater than the 95th percentile is found.
On confirmation of major genetic or structural anomalies,
termination of pregnancy is offered and foetal autopsy performed.
A foetal radiography is also included before pathological examination.
In a five-year period,
two hundred and nineteencases where nuchal translucency was greater than the 95th percentile were reviewed and radiological-pathological correlation performed on pregnancy termination cases.
Pathology
nº of cases (39)
Down syndrome
17
Edwards syndrome...
Conclusion
NT has been proven to be a useful first trimester ultrasound marker for
potential severe conditions.
As the thickness of the NT increases,
the odds of
abnormal karyotype,
major congenital anomaly and unfavourable outcome
increase.
To better diagnose specific diseases,
it is important to recognise adicional
ultrasound anomalies or markers,
which can be better understand by radiologic-pathologic correlation.
Personal information
As the first author,
Diogo Castelo,
Radiology resident at Centro Hospitalar de Vila Nova de Gaia e Espinho (CHVNG/E),
would like to manifest gratitude to his co-workers,
to the Obstetrics diagnostic unit from CHVNG/E and to the CGC Genetics,
in accompanying this review and for all the iconographic material provided.
References
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Nicolaides KH,
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Byrne D,
Mansur C,
Marks K.
Fetal nuchal translucency: ultrasound screening for chromosomal defects in first trimester of pregnancy. BMJ.
1992;304(6831):867-9;
2.Hinshaw HK.
Fetal nuchal translucency: ultrasound screeningfor fetal trisomy in the first trimester of pregnancy. Br J Obstet Gynaecol.
1995;102(9):758;
3.
Vieira LA,Silva SV,
Faria RB,
et al.Perinatal and pediatric follow up of childrenwith increased nuchal translucency and normal karyotype.Rev Bras Ginecol Obstet.
2013; 35(6):274-80.
4.1.
Ayras O,
Tikkanen M,
Eronen M,et at.Increased nuchal translucency and pregnancy outcome:retrospective study...