title: Fetal gastrointestinal MRI: all that glitters in T1 is not necessarily colon.
abstract: BACKGROUND
  It has been described that both the colon and distal ileum present with a physiological hypersignal on T1-weighted sequences during the second and third trimesters of pregnancy because of their protein-rich meconium content, it was unclear whether the normal characteristics that have been described on fetal MRI can be applied to gastrointestinal (GI) obstructions.
  
  
  OBJECTIVE
  To analyse the localisation value of T1 hypersignal within dilated bowel loops in fetuses with gastrointestinal tract obstruction.
  
  
  METHODS
  A retrospective 4-year multicentre study analysing cases of fetal GI obstruction in which MRI demonstrated T1 hypersignal content in the dilated loops. Data collected included gestational age (GA) at diagnosis, bowel appearance on US, CFTR gene mutations and amniotic levels of gastrointestinal enzymes. The suggested prenatal diagnosis was eventually compared to postnatal imaging and surgery.
  
  
  RESULTS
  Eleven patients were included. The median GA at US diagnosis was 23 weeks (range 13-32). In eight cases there was a single dilated loop, while several segments were affected in three. The median GA at MRI was 29 weeks (range 23-35). One case presented with cystic fibrosis mutations. Final prenatally suspected diagnoses were distal ileal atresia or colon in nine cases and proximal atresia in two. Postnatal findings were proximal jejunal atresia in nine cases and meconium ileus in two. In five cases the surgical findings demonstrated short bowel syndrome.
  
  
  CONCLUSIONS
  In cases of fetal occlusion, T1 hypersignal should not be considered as a sign of distal ileal or colonic occlusion. The obstruction may be proximal, implying a risk of small bowel syndrome, which requires adequate parental counselling.
authors.affiliation: Service de Radiopediatrie, La Timone Children's Hospital, 264 rue saint-Pierre, Marseille 13385, France. marina_colombani@yahoo.fr
authors.forename: Marina
authors.initials: M
authors.lastname: Colombani
authors.forename: Mathilde
authors.initials: M
authors.lastname: Ferry
authors.forename: Catherine
authors.initials: C
authors.lastname: Garel
authors.forename: Marie
authors.initials: M
authors.lastname: Cassart
authors.forename: Alain
authors.initials: A
authors.lastname: Couture
authors.forename: Laurent
authors.initials: L
authors.lastname: Guibaud
authors.forename: Fred
authors.initials: F
authors.lastname: Avni
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gorincour
mesh_terms: D003106:Colon / Q000473:pathology*; D005260:Female; D005315:Fetal Diseases / Q000473:pathology*; D006801:Humans; D007415:Intestinal Obstruction / Q000473:pathology*; D007422:Intestines / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011296:Prenatal Diagnosis / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity