RT Book, Section
A1 Monteagudo, Ana
A1 Timor-Tritsch, Ilan E.
A2 Malinger, Gustavo
A2 Monteagudo, Ana
A2 Pilu, Gianluigi
A2 Paladini, Dario
A2 Timor-Tritsch, Ilan E.
SR Print(0)
ID 1194695773
T1 Anomalies of Neural Tube Development
T2 Timor's Ultrasonography of the Prenatal Brain, 4e
YR 2023
FD 2023
PB McGraw Hill Education
PP New York, NY
SN 9781260136166
LK obgyn.mhmedical.com/content.aspx?aid=1194695773
RD 2024/04/18
AB KEY  POINTSFailure  of  closure  of  the  neural  tube  during  neurulation  results  in  neural  tube  defects.  Neurulation,  both  primary  and  secondary,  are  completed  by  approximately  32  post-ovulatory  days.All  cases  of  anencephaly,  approximately  80%  of  spina  bifida,  and  18%  of  cephaloceles  are  open  lesions.  In  cases  of  closed  neural  tube  defects,  the  maternal  serum  alpha-fetoprotein  (MSAFP)  is  normal  and  the  diagnosis  is  made  at  the  time  of  the  ultrasound  examination.In  the  first  trimester,  open  spina  bifida  can  be  diagnosed  by  direct  observation  of  the  spinal  defect  or  by  using  several  posterior  brain  “clues”  such  as  non-visualization  of  the  intracranial  translucency  (IT)  and  cisterna  magna  (CM);  increased  brainstem  (BS)  diameter;  decreased  brainstem  to  occipital  bone  (BSOB)  diameter  as  well  as  increased  BS–BSOB  ratio.During  the  second  and  third  trimesters,  diagnosis  of  spina  bifida  can  be  made  by  direct  observation  of  the  spinal  defect  or  by  the  “classic”  intracranial  sonographic  signs,  namely  the  “lemon”  and  “banana”  signs.Anencephaly  is  a  lethal  malformation.  The  outcome  of  cephalocele  is  dependent  on  the  size  and  presence  of  associated  anomalies  or  genetic  syndromes.  Open  spina  bifida  and  Chiari  II  malformation  are  not  lethal  anomalies,  although  they  are  associated  with  a  significant  amount  of  morbidity  and  mortality.Recurrence  risk  for  neural  tube  defects  (NTDs)  ranges  between  2%  and  5%.