fetal GIT anomalies prenatal ultrasound

1. IMAGING OF FETAL GIT
ANOMALIES
PRESENTER : DR. DEEPAK GARG

2. the human embryo develops into a bilaminar disk of ectoderm and
endoderm, with the endoderm forming the lining of the yolk sac. The
endoderm is the scaffold for the future digestive tract.
lateral folds , causing the endoderm to roll into a gut tube and pulling
the amnionic cavity to surround the embryo.
The head, tail and lateral folds draw the ventral body wall into a narrow
region around the connecting stalk – the umbilical ring . Note how the
gut tube is pinched off from the yolk sac to form the narrow vitelline duct
.

3.  Stomach forms at about 4 weeks & descends into
abdomen from initial position at about 7 weeks
 Abdominal wall muscles develop at about 11 weeks
 Stomach can be seen on ultrasound at about as early as
7 weeks & should b routinely noted by 13 – 14 wks of
gestation

24. CLASSIFICATION OF FETAL
GI ANOMALIES
 esophageal atresia/ TEF
 duodenal atresia/ stenosis
 Small-bowel atresia
 Meconium ileus
 Anorectal atesia
 hepatomegaly
 Splenomegaly
 Omphalocele
 Gastroschisis
 Cystic anomalies like : choledochal cyst etc

25. ESOPHAGEAL ATRESIA–
TRACHEO–ESOPHAGEAL (TE)
FISTULA
 Defect : lack of development of the intermediate esophageal
portion, mainly because of an interruption of the blood
supply during organogenesis.
 Communication between the proximal and the distal tract of
the esophagus is absent
 can occur as an isolated anomaly (10% of cases) or,
frequently, be associated with a (TE) fistula (90% of cases)
 VAC(TE)RL association

26. Oesophageal atresia without
fistula(blind pouches) 10%
(TYPE A)
Proximal fistula with
distal blind pouch
<1% (TYPE B)

27. Proximal and distal
fistulae
<1%(TYPE D)
"H"-type fistula
4%(TYPE E)
Distal fistula with
proximal blind pouch
87% TYPE C)
Type c,d and e are difficult to detect on usg as through trachea, some
amniotic fluid may actually reach the distal esophagus and eventually
fill the stomach. So stomach bubble will not be absent in these cases

28. IMAGINGUSG :
- Non-visualization of the gastric bubble
- Polyhydramnios
- Dilatation of the proximal esophageal tract, the so-called “pouch sign”
- Presence of a small stomach (in type C,D - TEF)
- Evidence of FGR
- VAC(TE)RL association
so more than 85% of cases of esophageal atresia are not detected in utero coz
various signs of esophageal atresia can be present in one or the other conditions-
1.The highly indicative of esophageal atresia is non-visualization of the gastric
bubble. But stomach bubble is present in cases with distal TE fistula
2. polyhydramnios, it becomes clearly evident only in the late 2nd trimester
3. Pouch sign can also be seen in the normal fetus after swallowing
4. FGR COZ OF an effect of the reduced intestinal absorption of the proteins
present in the amniotic fluid. But it is very non specific.

30. Esophageal atresia. (a) At 23 weeks of gestation, a suspicion of esophageal atreria
(without distal TE fistula) arises due to persistent non-visualization of the gastric
bubble in the abdomen. The amount of amniotic fluid is normal. (b) At 30 weeks of
gestation, polyhydramnios has developed and the stomach is still not visualized: the
diagnosis of esophageal atresia is confirmed.

31. DIFFERENTIALS…..
 Normal stomach that recently emptied
 Congenital diagphragmatic hernia
 Abdominal wall defects
 Situs inversus (total / partial)
 Anhydramnios
 Microgastria
 Aneuploidy

32. CONGENITAL DIAGPHRAGMATIC HERN
Congenital diaphragmatic hernia, Bochdalek type. In this variant of CDH, the stomach
(S) is visible in the middle of the thorax, or in the left hemithorax, while the mediastinum,
with the heart, is shifted contralaterally. RA, right atrium; LV, left ventricle.

33. FADS, fetal
akinesia
deformation
sequence…
here the
swallowing
reflex is
blocked due
to contracture
of the
masseters
and the
pharyngeal
muscles.
This leads to
polyhydramni
os on the one
hand and to
non-
visualization
of the
stomach on
the other.

35. DUODENAL
ATRESIA/STENOSIS

36. DUODENAL ATRESIA/STENOSIS
 Highly associated with trisomy 21
 TYPES :
- complete (80%)
- Partial (20%)
 IMAGING :
- classic “double bubble” sign
- Polyhydramnios

37. –In most cases (80%), the obstruction is due to complete
atresia and is caudal to the ampulla of Vater.( due to
Annular pancreas or Occlusion by SMA)
In the remaining 20% of cases, the obstruction can be
due to a membrane located within the lumen of the
duodenum.
In partial obstruction- the double bubble may become
visible only late in gestation or may even never occur,
with a constantly dilated stomach with evidence of the
pylorus being the only sign of the partial obstruction.

38. DUODENAL
ATRESIA/STENOSIS
Duodenal atresia. (a) At 23 weeks of gestation, initial evidence of a double bubble is
detected (arrow).
(b) After few minutes, intestinal peristalsis demonstrates the communication between
the stomach and the dilated proximal duodenum in longitudional view

39. A. ) Later in gestation, a clear double bubble (arrow) has developed, confirming the
suspicion of duodenal atresia
B.. Duodenal atresia in an 8-hour-old female neonate who presented with bilious vomiting.
Abdominal scout radiograph shows a markedly distended stomach and duodenum with no
gas in the rest of the intestinal tract (double bubble sign).

40. DIFFERENTIALS….
conditions featuring a cystic structure in the middle or right
upper abdomen
 Choledochal cysts
 Hepatic cysts
 Renal cystic disease
 HDN
 Meconium pseudocyst
 Mesenteric/ Omental cyst

41. CHOLEDOCHAL CYST
It may be seen as an anechoic fetal intra-abdominal cyst within or close to the
fetal liver.
Demonstration of continuity with the fetal gall bladder or hepatic ducts or
presence of associated intra- and extrahepatic ducts may further further aid
the diagnosis

42. MECONIUM
PSEUDOCYST
When meconium is walled off after perforation, along with dilated small bowel
loops, a large cyst with echogenic contents, intracystic calcification, marked
polyhydramnios, a diagnosis of giant cystic meconium peritonitis should be
made. Meconium pseudocyst (arrow) in a second trimester fetus with meconium
peritonitis.

43. HYDRONEPHROSIS
Coronal scan of the kidney in a case of uretropelvic junction (UPJ) obstruction;
the renal pelvis (RP) and calyceal distension (arrows) end abruptly at the
ureteral junction.
(b) Severe UPJ obstruction presenting as an abdominal cyst; the renal
parenchyma is thinned to a few millimetres. + FEATURES OF

45. SMALL-BOWEL ATRESIA
JEJUNOILEAL ATRESIA
Best diagnostic clue:
- late onset dilated, fluid-filled loops of bowel ( largest
transverse lumen dia >7 mm) with hyperechoic walls
- Hyperperistalsis within small bowel loops highly suggestive of
obstruction
- Rarely presents as a cyst-like mass
-Late onset polyhydramnios
DIFFERENTIALS…Hirschprung’s disease (aganglionic megacolon)
meconium ileus

47. JEJUNAL ATRESIA
Jejunal atresia (37 weeks of gestation). Note the extremely severe dilatation
without evidence of perforation (absence of meconium peritonitis). The
arrowheads indicate the site of the peristaltic wave, opening and closing the
communication between adjacent loops from (a) to (b).

48. ILEAL ATRESIA
24 weeks 30 weeks 36 weeks
. (a) Before 24 weeks of gestation, there is hardly any evidence of intestinal
dilatation. The only doubtful sign is moderate dilatation (> 7 mm) of a single
ileal/jejunal loop, possibly associated with a hyperechoic wall (arrowheads).

49. ILEAL ATRESIA
24 weeks 30 weeks 36 weeks
(b) In the 3rd trimester, the obstruction becomes evident, with moderately severe
dilatation of various loops. In the dilated bowel loops cranial to the obstruction,
increased intestinal peristalsis is seen, with the intestinal content moving from one loop
to the adjacent one.

50. ILEAL ATRESIA
24 weeks 30 weeks 36 weeks
. (c) At 36 weeks, by following the course of the dilated loops, it is
possible to demonstrate the communication between the various dilated
segments (the maximum transverse diameter of the loops was 23 mm).

51. ILEAL ATRESIA
(a) Upright radiograph shows multiple air-fluid levels occupying the entire abdominal
cavity. (b) Image from a barium enema study shows numerous dilated, air-filled loops
of bowel and a small, unused colon (functional microcolon).

52. MECONIUM ILEUS
 Meconium ileus is characterized by an ileal mechanical obstruction
caused by inspissated meconium,(the primary cause of which is
cystic fibrosis)
 ETIOPATHOGENESIS : high protein content
less fluids
significant inspissation
blocks the intraluminal transit of the meconium
Intestinal obstruction
perforation

53. IMAGING
 multiple dilated loops
 hyperechoic content within gut loops
 hyperechoic walls
 ascites
 Diffuse intra-abdominal calcifications
first evidence of meconium ileus at ultrasound consists of the so-called
HYPERECHOIC ILEUS

54. Meconium ileus. (a) At 29 weeks of gestation, some ileal loops are dilated and show
hyperechoic walls (arrow). The presence of macrocalcifications (arrowheads)
demonstrates the perforation and the consequent meconium peritonitis
(b): an oblique view of the abdomen also demonstrates the presence of a secluded
sac of ascites containing meconium sludge (arrow).

55. (d) Another case showing diffuse intra-abdominal
calcifications (arrows), consistent with a diagnosis of
meconium peritonitis.

59. ANORECTAL ANOMALIES
TYPES :
- External : imperforate anus with/without fistula
- Internal : pure rectal atresia and rectal atresia with fistula
- Mixed : ectopic anus
Anorectal malformations can be divided, on the basis of their
embryologic origin, into the following:
EXTERNAL : due to abnormalities of the development and fusion
of the external perineal layers.
INTERNAL : developmental anomaly involves the primary partition
of the cloaca by the urogenital septum.

60. IMAGING :
 overdistended rectum & Sigmoid Colon with
normal liquor.
 Liquor is decreased when associated with
rectovesical fistula.
 rectal pouch is larger than full bladder, and
with a bilobed appearance

61. Anorectal atresia. (a) Normal filling of the rectal pouch (arrow) behind the
bladder (BI).
(b) Evident dilatation of the rectum, which also shows hyperechoic content
(arrows).

62. (c) The fetus after termination of pregnancy. In addition to other
anomalies, anorectal atresia was confirmed: the anal orifice is not visible

67. o We should use probe of frequency less
than 5 MHz. High frequency transducers
give false positive results
 Echogenic bowel suggests bowel
compromise. In approximately one third of
fetuses with echogenic bowel on prenatal
ultrasonography, a malformationof the GI
tract is later confirmed
 Diagnosis is highly operator dependent

68. Iliac crest is used as an internal standard as it can usually be imaged at the same
level as the bowel.
Increasing echogenicity (and therefore a higher grade) correlates with increased risk of a
fetal abnormality
A detailed ultrasound of the fetus should be performed (careful evaluation of the amniotic
fluid, placenta, and membranes, for any features of intra-amniotic bleeding, such as
particulate debris or clot floating in the amniotic fluid or chorioamniotic separation).

73. FETAL CMV
Echogenic bowel in fetal CMV infection

74. ANOMALIES OF ABDOMINAL
WALL
EMBRYOLOGY

75. ANOMALIES OF ABDOMINAL
WALL
 Omphalocele
 Gastroschisis
 Ectopia cordis
 Cloacal exstrophy
 limb–body–wall complex

76. OMPHALOCELE
 Omphalocele is a defect in the closure of the abdominal wall
leads to herniation of abdominal viscera
USG : -
 bulging structure
(i) arises from the anterior abdominal wall
(ii) contains some abdominal viscera (liver and/or bowel)
(iii) presents the cord insertion on its convexity
 Ascites
 Polyhydramnios
The presence of the umbilical vein within the omphalocele is an
indirect sign of the fact that this anomaly represents a
primary closure defect of the abdominal wall

77. OMPHALOCELE
The herniated organs are wrapped in a two-layered sac, with the two layers being the
peritoneum and the amnion.
The cord insertion is located on the top of the sac.
Two variants of omphalocele exist, according to the presence or absence of the liver in
the sac.

78. A.At 23 weeks of gestation, the axial view of the abdomen
demonstrates a large omphalocele containing the liver (the
arrows indicate the large wall defect).

79. A.Midsagittal view of the abdomen: a case of omphalocele containing the liver at
29 weeks of gestation (normal karyotype). LIVER in herniated sac is sure
short sign of omphalocoele
B.Rarely, ascites can be associated with the omphalocele and can be detected
in the sac (Asc); color Doppler shows the umbilical vein.

80. DIFFERENTIAL
DIAGNOSIS
 physiologic herniation in the cord
 gastroschisis
 limb–body–wall complex
 cloacal exstrophy
Normally physiological herniation gets corrected by 11 wks of gestation, If
an omphalocele containing only ileal loops is identified earlier than the 12th
week of gestation, the fetus should be rescanned in a week’s time: if the
herniation persists, then it is an omphalocele

81. GASTROSCHISIS
 Paraumbilical defect of the abdominal wall through which
bowel loops herniate to float freely in the amniotic fluid
 Etiopathogenesis : - abnormal regression of the right UV
- vascular accident during embryogenesis
 USG : - freely floating bowel outside the fetal abdomen
- identification of the right para-umbilical wall defect
- Normal cord insertion.
- thickening and edema of the intestinal walls with signs
of obstruction

82. GASTROSCHISIS
•herniated viscera consist, in the overwhelming majority of cases, of bowel loops only; in
very rare circumstances, the stomach and urogenital structures may herniate as well. As
already pointed out, there is no membrane wrapping the herniated viscera and these float
freely in the amniotic fluid.
•defect is small (< 2 cm),& this is responsible for occurrence of bowel infarction due to
torsion and/or compression of the mesenteric pedicle on the rim of the defect

83. Gastroschisis at 16 weeks of gestation. showing the
bowel loops floating freely in the amniotic fluid

84. Gastroschisis at 31 weeks of gestation. The appearance of
bowel dilatation in the 3rd trimester represents a
complication, indicating a likely obstruction. This situation
may evolve with perforation and/or necrosis of one or more
bowel loops.

85. Axial view demonstrating some meconium blocked in the dilated loop
(arrowhead).

86. LIMB–BODY–WALL
COMPLEX
Limb–body wall complex consists of a variable groups of congenital limb
and body wall defects of the chest and abdomen
a) Free floating complex mass containing liver with short umbilical cord
originating from the placenta to the mass

87. LIMB–BODY–WALL
COMPLEX
a. Coronal MR images show large anterior abdominal wall defect (arrows)
with liver (L) and bowel (B) attached to placenta (P).
b. Sagittal MR image shows heart (H), liver (L), and bowel (arrows) protruding
through anterior abdominal and chest wall defect.

88. PENTALOGY OF CANTRELL
 Pentalogy of Cantrell : omphalocele,
ectopia cordis,
diaphragmatic defect,
pericardial defect, and
cardiovascular malformation
The cause of pentalogy of Cantrell is failure of the lateral body
folds to fuse in the thoracic region, with variable extension
inferiorly

89. Transverse sonogram demonstrates the nearly complete exteriorization of the heart
(arrow).
Longitudinal sonogram shows a large omphalocele (arrowheads) extending
cephalad to involve the region of the sternum. Ectopia cordis was also present.

90. CLOACAL EXSTROPHY
Failure to visualize the bladder in the pelvis. Sagittal view of the lower
body, showing the omphalocele (arrowheads) and the bladder exstrophy
(arrows).

93. HEPATOMEGALY
(HEPATITIS)
• Causes
• Intrauterine fetal infections( CMV)
,hepatitis are among the most common
causes of hepatosplenomegaly
• Down syndrome may be responsible, in
some cases, for moderate to severe
hepatomegaly.
• Rare benign and malignant hepatic
tumors, such as hemangioma or
hepatoblastoma.
• fetal anemia
• Beckwith–Wiedemann and Zellweger
syndromes

94. Hepatomegaly. This patient had serologically confirmed hepatitis A
infection in the 1st trimester. At 19 weeks, ultrasound demonstrated the
following: (a) Axial view: evident hepatomegaly, with capsular
macrocalcification and moderate ascites. (b) Left parasagittal view: The
ascites and moderate enlargement of the left hepatic lobe (LL, arrowheads)
are shown; in such a situation, the left hepatic lobe should not be mistaken
for the spleen.

95. HEPATOMEG
ALY
( CMV)Severe hepatomegaly due to
CMV infection.
(a) on the axial view of the
upper abdomen, it is
possible to recognize the
enlarged, hyperechoic, and
rather inhomogeneous liver
(arrows).
(b) On the right parasagittal
view, the degree of
hepatomegaly is easily
evaluated and the
prominence of the abdomen
in comparison with the
normal thorax is evident
(arrowheads

96. INTRAHEPATIC
CALCIFICATIONSA and b show calcification in
the fetal liver. The maternal
history was unremarkable,
and the outcome was normal.
C and D show diffuse
punctate calcifications in
fetal liver.
an infectious cause was
thought to be likely.

97. SPLENOMEGALY
Splenomegaly in two cases of severe fetal CMV infection. (a) On the coronal
view, at 37 weeks of gestation, it is possible to recognize the severely
enlarged spleen (Spl), the lower pole of which reaches the bladder (Bl) and a
concurrent similarly severe hepatomegaly (Li).
(b) A similar case, at 36 weeks of gestation, showing severe
hepatosplenomegaly, ascites, and intra-abdominal calcifications. Both
neonates died of widespread CMV infection.

98. FETAL GALLSTONES
Fetal gallstones. (a)
Coronal sonogram
obtained at 16 weeks
gestation shows
shadowing stones in the
fetal gallbladder.
Postulated causes of fetal
gallstones include
hemolytic disease,
cholestasis, and maternal
drug use. These stones
resolve immediately in post
natal life.

99. NEUROBLASTOMA
a. Neuroblastoma with hemorrhage in fetus at 34 weeks' gestational age referred
for evaluation of right suprarenal mass. Coronal sonogram of fetal abdomen
shows complex mass (arrow) above right kidney (arrowheads). No normal
adrenal tissue is identified.
b. Sagittal MR shows hyperintense well-demarcated lesion (arrow) above right
kidney (arrowheads).

100. CONCLUSION
 A wide spectrum of abdominal anomalies can be seen in utero.
 Look for any systemic involvement
 Most of GI anomalies show similar features like cysts,
abdominal wall defects
 Follow up of growth & assessment of progression of bowel
obstruction is important in atresias
 MRI is problem solving tool.