PRESENTATION ON PRENATAL IMAGING OF LIVER & GIT

1. BY-
Dr. Nidhi Aggarwal

2. Intestinal obstruction
 Esophagus
 Stomach
 Duodenum
 Small bowel
 Colon
 Anorectal

3. Esophageal Atresia
 Developmentally, the trachea and esophagus differentiate inferiorly from
the posterior pharynx. Incomplete differentiation of the respiratory and
GI tracts can lead to esophageal atresia with or without tracheoesophageal
(TE) fistulas.
 The incidence of TE fistulas, all types, is 2.8 per 10,000 pregnancies.
 Most types of esophageal atresia (90%) are associated with TE fistulas, and
therefore the stomach will be visualized on ultrasound.
 The combination of inability to see a stomach on ultrasound and
the presence of polyhydramnios is more suggestive of esophageal
atresia than absent stomach alone.
 Half of TE fistulas are part of the VACTERLsequence, a nonrandom group
of coexisting defects: vertebral defects, anal atresia, cardiac anomalies,
tracheoesophageal fistula with esophageal atresia, renal and radial
dysplasia, and limb defects. VACTERL has sporadic inheritance.
 Association with down’s syndrome.

5. Distension of a proximal esophageal pouch typically
intermittent either on ultrasound or MRI

6. Stomach
 The fetal stomach can be seen as early as 7 weeks .
 Should be noted routinely by 13 to 14 weeks’
gestation
 The stomach should be in the left upper
abdomen.
 Presence of a right-sided stomach and a right-
sided heart is termed total situs inversus.
 A right-sided stomach and a left-sided heart
result in partial situs inversus.

8. Small or Absent Fetal Stomach
 Fluid in the stomach should be reliably visualized on
first-trimester screening and all subsequent fetal
evaluations.
 Generally, the stomach will fill during a 30-minute
examination.
 Amniotic fluid in cases of absent stomach is typically
normal early in the second trimester, but
polyhydramnios is common by the third trimester.
 The finding of a persistently absent stomach on serial
ultrasound scans should trigger genetic counseling and
consideration of chromosomal testing.

9. ABSENT STOMACH
 Normal stomach that recently emptied
 Displaced stomach into chest in hernia
 Displaced stomach into abdominal wall defect
 Esophageal atresia
 Aneuploidy
 Anhydramnios
 Microgastria

10. Dilated Fetal Stomach
 In the second or third
trimester a prominent or
transiently dilated fetal stomach
may be seen on ultrasound.
 However, diagnosing a dilated
fetal stomach requires that the
stomach be persistently
dilated throughout a 30-minute
assessment.
 The differential diagnosis of a
dilated fetal stomach includes
normal fetus and
gastrointestinal
atresia(primarily duodenal
atresia).

11. Midline or Right-Sided Stomach
 When an apparently malpositioned stomach is noted,
the situs must again be carefully determined.
 A midline stomach can represent intestinal
malrotation. However, heterotaxy syndrome,
including right isomerism and left isomerism is more
common. It is characterized by an abnormal symmetry of
the viscera and veins and may be associated with
complex cardiac anomalies, intestinal malrotation,
and splenic (asplenia or polysplenia), and hepatic
abnormalities.
 The incidence of asplenia/polysplenia heterotaxy
syndromes is 0.45 per 10,000 pregnancies.

13. SMALL BOWEL AND COLON
 In the first trimester and early in the second
trimester, the small and large bowel appear
somewhat heterogeneous, with echogenicity
similar to but increased, compared to liver.
 Later in pregnancy, fluid can be seen in small
bowel loops.
 Meconium can be seen in the colon.
 All GI atresias are thought to represent a failure
of recanalization of the bowel lumen, which is a
solid tube early in fetal life.

14. Duodenal Stenosis and Atresia
 Dilation of the duodenum resulting from stenosis (obstruction) or
atresia is the most common bowel obstruction in the fetus;
occurring in 1 or 2 per 10,000 live births.
 Duodenal atresia is also associated with anomalies of the VACTERL
spectrum
 Diagnosis of duodenal stenosis is most common in the third trimester.
 Duodenal stenosis can be distinguished by hyperperistalsis of the
dilated proximal duodenum, whereas in DA, no peristalsis may exist at
all.
 DA is associated with malrotation of the bowel in approximately
29% of cases.
 Other causes for proximal obstruction include an adhesive Ladd band
in a patient with primary midgut malrotation, or annular pancreas.
 Duodenal obstruction typically has polyhydramnios.
The more proximal the atresia, the earlier and the more
frequently an abnormally large amniotic fluid volume tends
to present.

16.  The classic “double bubble” sign of a second
echolucent mass medial to the stomach (in a transverse
view of fetal abdomen) is considered diagnostic of
duodenal obstruction. Second bubble representing the
dilated duodenum proximal to the atretic area.
 Because an abdominal fluid collection can have other
etiologies, it is important to demonstrate a continuum
between the stomach and the cystic mass.
 Apparent double-bubble sign is also associated with
postnatal diagnoses of choledochal cyst and
duodenal duplication cyst.
 Finding the double-bubble sign should trigger genetic
counseling and consideration of amniocentesis because
of the association with trisomy 21.

17. Jejunal and Ileal Atresias
 The prevalence of jejunoileal atresias range from .54 to 1.11 cases per
10,000 live births.
 Jejunal atresias are slightly more common (51%than ileal).
 The most common etiology hypothesized for jejunoileal atresias is isolated
vascular compromise.
 Jejunal atresias have been associated with nonbowel anomalies in up to
42% of cases, with ileal obstructions associated with nonbowel anomalies
only in up to 2%.
 Jejunal atresias, however, are more likely to be multiple and less often
associated with in utero perforation than ileal atresias, likely because
of the lower compliance of the ileum.
 “Apple peel” jejunal atresia is a subtype that involves agenesis of the
mesentery, is more often familial,and is likely of a different etiology.
 Cystic fibrosis (CF) is a common underlying etiology for ileal obstruction,
with or without meconium-increased echogenicity noted prenatally.

18.  The small bowel is considered to be dilated if it is
larger than 7 mm.
 In proximal jejunal atresia, more loops will be dilated
than just the double bubble seen with DA (“triple
bubble” in very proximal jejunal atresia)
 In distal jejunal atresia and ileal atresia, multiple
dilated, fluid-filled loops are seen and typically a normal
amniotic fluid volume is present.

20. Colon
 Colonic atresias are difficult to diagnose specifically unless
the obstructed segment can be identified with certainty in the
expected location of the colon, or interhaustral notches can
be separated from valvulae conniventes on ultrasound.
 Meconium typically is seen in the rectum by 20 weeks’
gestation, in the left colon by 24 weeks’ gestation, and in the
right colon by 31 weeks’ gestation, but this pattern may be
altered by the pathology that is present.
 On FSE T2-weighted sequences, meconium has a very
low signal, whereas it shows a high signal on T1 weighting.
 In general, when dilated loops are discovered, ultrasound
is sufficient to diagnose the level of obstruction as proximal
versus distal and to generate a focused differential
diagnosis.
 Fetal MRI is reserved for complex cases.

21. Causes of non visualization of
meconium
 Bowel obstruction
 Bowel perforation (meconium peritonitis/pseudocyst)
 Megacystic-microcolon-hypoperistalsis syndrome
 Cloacal exstrophy
 Cloacal malformation
 Congenital diarrhea syndromes

22. Anorectal Atresias
 Of the large colon atresias, anorectal
atresia is the most common. The
incidence is 0.8 to 4 per 10,000
live births.
 associated with VACTERL sequence.
 Proximal bowel dilation is
uncommon,
 On ultrasound and MRI, the
diagnosis may be suspected if the
characteristic hypoechoic
configuration of the anal
musculature is absent. Also, a cord
or ridge of abnormal fibrous
tissue at the perineum may be
imaged by ultrasound or MRI.

23. Megacystis and Microcolon
 In megacystis-microcolon–intestinal
hypoperistalsis syndrome,there is a
distended bladder and at times a
dilated small bowel.
 There is a 4:1 female predominance
 Magnetic resonance imaging (MRI)
can be helpful in identifying the
microcolon.

24. MECONIUM PERITONITIS
AND PSEUDOCYST
 Meconium peritonitis is a result of in utero small bowel perforation
and subsequent extrusion of meconium intraperitoneally.
 Calcifications can be seen in the peritoneum, outlining bowel or liver.
 When the extruded meconium becomes walled off in the
peritoneum and develops a heterogeneous cystic appearance, this is
termed a meconium pseudocyst.
 Associated ultrasound findings include ascites, polyhydramnios,
and dilated bowel. Both meconium ileus and meconium peritonitis
are associated with CF in 8% to 40% of cases.
 Meconium peritonitis has been classified to predict a postnatal
surgical requirement.
 The risk of need for postnatal surgery increases with the number
of findings. Once meconium peritonitis or ileus has been diagnosed,
serial fetal sonography in recommended.

25. MECONIUM PERITONITIS: NEED
FOR POSTNATAL SURGERY (%)
 Isolated calcifications: 0%
 Calcifications and pseudocyst,
ascites, or bowel dilation: 52%
 Calcifications and two of
pseudocyst, ascites, or bowel
dilation: 80%
 Calcifications, pseudocyst,
ascites, and bowel dilation: 100%
 Polyhydramnios and any of above
findings: 69%

28. Echogenic Bowel-
 Hyperechogenicity of the bowel is described when
echoes of the bowel are as echogenic as the iliac crest
with the ultrasound gain at the lowest gain, where
bone looks white in the second trimester of pregnancy
 As the echogenicity of normal bowel increases
throughout pregnancy, the finding of echogenic bowel
becomes normal in the third trimester.
 In particular, meconium in the colon can be seen normally
as echogenic material in the third trimester.

29. ECHOGENIC BOWEL: COMMON
ASSOCIATED RISKS
 Aneuploidy
 Cystic fibrosis
 Swallowed fetal blood
 Infection
 Gastrointestinal atresias
 Intrauterine growth
restriction
 Fetal demise

30. Echogenic bowel with Aneuploidy
 The most common abnormal karyotype is trisomy 21,
but trisomies 13 and 18, 45,X, and triploidies have all
been reported in fetuses with echogenic bowel.
 Trisomy 21 is associated with GI dysfunction and
dysmotility.
 Thus, it is hypothesized that the dysmotility is the
pathophysiologic cause of the echogenicity in
aneuploid fetuses.

31. Echogenic bowel &Cystic Fibrosis
 Echogenic bowel, meconium cysts, and
peritonitis are the sonographic findings visible in
the second trimester in fetuses with CF. With
confirmed diagnosis of CF, the echogenic
appearance of the bowel is caused by the
biochemical alterations in the secretory-
digestive-absorptive function of the small intestinal
mucosa, leading to meconium obstruction in small
bowel, primarily meconium ileus.

32. Swallowed Fetal Blood
 Echogenic bowel has been noted in pregnancies
complicated by vaginal bleeding, in those with
asymptomatic subchorionic hemorrhage, and
with the unexpected finding of new or old blood on
amniocentesis performed for chromosomal
analysis.

33. Fetal Viral Infection
 Fetal viral infections including cytomegalovirus(CMV)
and parvovirus infection are other associated
etiologies of echogenic bowel.
 The etiology of the echogenic bowel in fetuses with
viral infection is not known.
Intrauterine Growth Restriction and Fetal
Demise
 The risk of both intrauterine growth restriction (IUGR)
and fetal demise increases in the second and
third trimesters after the second-trimester diagnosis of
echogenic bowel. Incidence is 10% for IUGR and 5.8%
to 15% for fetal demise.

34. Fetal Ascites
Serous
• Bowel perforation (fluid may be complex)
• Hydrops: immune and nonimmune (most common cause)
• Ruptured or torted ovarian cyst
• Cardiac decompensation
• Hypoproteinemia
• Hepatic dysfunction (storage disorders, mass, infection)
Bilious
• Perforation of a choledochal cyst
Chylous
• Thoracic duct obstruction, increased intrathoracic pressure
• Lymphatic malformation (e.g., Klippel-Trenaunay syndrome)
• Mesenteric lymphangiomatosis
Hemorrhagic
• Rupture of a vascular tumor
• Trauma
Uriniferous
• Perforation of the collecting system or bladder
• Cloacal malformation, urogenital sinus

35. ABDOMINAL WALL
Embryology
 The embryonic abdominal wall develops from the lateral plate mesoderm
and endoderm in later embryonicdevelopment (days 16-26). Each lateral
plate splits horizontally into the parietal and visceral mesoderm.
 The space between these layers becomes the body cavity (coelomor
celum).
 Normal development of the abdominal wall requires enfolding of the
lateral plate around the coelom in several dimensions: caudally, cephalad,
and laterally.
 In the normal enfolding process, the lateral folds come together before the
normal gut rotation, leaving a physiologic gut herniation into the coelomic
outpouching of the umbilical cord insertion.
 This herniation is usually visible on ultrasound from 9 to 11 weeks.

36.  If craniad infolding fails, the resulting defect
would be to the abdominal wall and lower chest
.
 Lateral fold defects lead to an omphalocele (the
most common isolated ventral wall defect )
 Caudal fold failure results in bladder or cloacal
exstrophy.

37.  Abdominal wall defects include gastroschisis,
omphalocele, ectopia cordis, cloacal exstrophy,
and amniotic band syndrome (limb–body wall
defects). The overall incidence of abdominal wall
defects is 6.3 per 10,000 pregnancies.
 Because of the loss of integrity in the
epidermal covering, abdominal wall defects are
associated with elevations of maternal serum alpha-
fetoprotein (MS-AFP).

38. Gastroschisis Omphalocele
 Gastroschisis is a full-thickness
paraumbilical defect of the abdominal
wall, most often right sided.
 Unlike omphalocele, free-floating loops
of bowel in the amniotic fluid are
the key finding on ultrasound.
 No gender predilection in the affected
fetuses.
 Particularly in young women,
gastroschisis is associated with use of
tobacco, illicit drugs, and
pseudoephedrine.
 Increased risk of preterm birth weight
(<10%) and a relatively high stillbirth
rate.
 Associated GI abnormalities (atresias,
stenosis, perforations, or volvulus) are
common (11%-31%).
 Etio- isolated vascular compromise of
the abdominal wall in the first trimester,
failed development of the mesoderm
and the lateral mesodermal enfolding.
 Omphalocele is a midline abdominal
wall defect into which the abdominal
contents are extruded.
 It is covered by amnion and peritoneum
.
 most common in women 35 to 40 years
old.
 Omphaloceles have a higher risk (10%-
30%) of chromosome abnormalities
than gastroschisis (aneuploidies trisomies
13 and 18, 21).
 Omphalocele has a 55% to 58% risk
of associated anomalies, including
midline defects (cardiac, clefting, and
spinal/vertebral anomalies), clubfoot,
and central nervous system anomalies.
 Omphalocele is also part of Beckwith-
Weidemann syndrome
 The etiology of development of
omphalocele is multifactorial including
failure of closure of the lateral
mesodermal folds.

42. Ectopia Cordis
 Ectopia cordis is a midline fetal
defect with all or part of the heart
extruded out of a sternal defect,
with or without a membrane .
 Trisomy 18 is associated with
this diagnosis.
 If craniad infolding fails, the
resulting defect would be to the
abdominal wall and lower
chest.
 Pentalogy of Cantrell
(omphalocele, sternal defect,
ventral mediastinal diaphragmatic
hernia, pericardial defect, and
ectopia cordis)

43. Amniotic Band Syndrome and
Limb–Body Wall Complex
 Amniotic band syndrome can affect any part of the fetus.
 If a band has disrupted development of the anterior abdominal wall, the
defect can appear similar to a gastroschisis .
 Extended and complex midline defects of the abdominal wall or thorax
are generally categorized as limb–body wall complex or body stalk anomaly.
 These defects are often one aspect of a fetus with multiple anomalies and
are associated with limb or spinal defects, craniofacial defects,
exencephaly, or encephaloceles.
 The first type, phenotypically characterized by craniofacial defects,
amnion bands, and adhesions, is caused by vascular disruption or
amnion rupture in very early pregnancy.
 The second type has no craniofacial defects but rather urogenital
anomalies (including cloacal and bladder exstrophies), anal atresia, and
abnormalities of the placental attachment site, as well as persistence of the
extraembryonic coelom. This type is thought to be caused by fetal
maldevelopment.
 Oligohydramnios is common.
 The prognosis for both types, in the absence of amniotic fluid, is universally
fatal.

45. Bladder Exstrophy
 In bladder exstrophy, the ventral wall of the
bladder, inferior rectus musculature, and skin are
absent, and the residual dorsal wall of the bladder is
continuous with the abdominal wall.
 Sonographic diagnostic criteria include the
presence of an infra-abdominal mass and inability to
visualize a bladder. There is an inferiorly displaced
umbilical cord,usually with a unilateral umbilical
artery .

46. Omphalocele-Exstrophy–
Imperforate Anus–Spinal Defects
 (OEIS) complex was formerly known as cloacal exstrophy .
 The OEIS defects probably result from failure of fusion of the
abdominal cloaca and exstrophy of the common cloaca that
receives ureters, ileum, and a rudimentary hindgut.
 Additional findings occur in the genital tubercles and pubic rami,
with incomplete development of the lower vertebrae. Imperforate anus,
cryptorchidism, and epispadias occur in males, with anomalies of the
müllerian duct derivatives in females, as well as a wide range of
urinary tract anomalies, including renal agenesis.
 Criteria for sonographic diagnosis of OEIS are nonvisualization of
the bladder associated with a visualized persistent cloaca, presence of
an omphalocele, and spinal defects, typically neural tube defects or
tethered cord.
 Single umbilical artery is a common associated finding.
 Diagnosis of OEIS has been reported as early as 13weeks.
 Both bladder and cloacal exstrophy include diastasis of the pubic
symphysis and may have more complex pelvic bone deformities.

47. LIVER
 The fetal liver is clearly visualized in the upper abdomen
in the second half of gestation, although earlier in
gestation it has an echogenicity similar to renal echoes.
 In the fetus, the left side of the liver is larger than
the right side. The liver increases in size during
pregnancy.
 Hepatic calcifications may be noted in utero. The
pathophysiology of the calcifications in otherwise
normal fetuses is unknown. These are typically isolated
and of no clinical consequence. However, hepatic
calcifications have been reported in aneuploid or CMV-
infected fetuses with additional anomalies.

48.  When hepatic calcifications are visualized, it is
important to distinguish from calcifications that
line the liver and peritoneal cavity in fetuses
with meconium peritonitis.
 Color flow Doppler ultrasound is recommended
to distinguish vascular lesions.
 Vascular hepatic lesions have been noted to serve
as vascular reservoirs, leading to high-output cardiac
failure and fetal hydrops.
 Following these fetuses sonographically with
middle cerebral artery and ductus venosus
Doppler imaging may be helpful because of the
ability to predict fetal anemia of other etiologies.

51. BILIARY SYSTEM
 The normal fetal gallbladder
is an oblong, echolucent
structure in the anterior liver
,generally located 45 degrees
to the right of midline and
inferior to the umbilical vein.
The gallbladder increases in
size with gestational age.
 Visualization of the
gallbladder was most
common from 20 to 32
weeks.
 Nonvisualization of the
gallbladder is associated with
cystic fibrosis, gallbladder
atresia, and biliary atresia.

52.  Echodensities in the fetal gallbladder can be either
sludge or gallstones. They are primarily seen in the third
trimester.
 Gallstones are generally reported to have acoustic shadowing
. If there is no shadowing, it is assumed that the echogenic
debris represents sludge. In most cases, postnatal resolution
occurs, and children are asymptomatic.

53.  Enlarged gallbladder is
associated with fetal
aneuploidy.
 Cystic lesions of the
biliary tree have been
identified in utero. These
cysts may be anechoic,
may have echogenic
debris, or may
represent a bilobed
gallbladder.
 Choledochal cysts most
often represent dilation
of the common bile duct.

54. PANCREAS
 Pancreatic abnormalities reported prenatally
include polycystic pancreas and annular pancreas.
 The diagnoses of annular pancreas were
triggered by sonographic assessment for a
dilated duodenum. Annular pancreas is associated
with as many as 33% of fetuses with prenatally
diagnosed duodenal atresias.

55. SPLEEN
 The fetal spleen can be visualized as an echogenic
organ in the left upper abdomen, lateral to the spine
and the upper renal pole.
 Abnormalities of the fetal spleen (asplenia or
polysplenia) are associated with heterotaxy
syndromes and warrant a detailed fetal cardiac
examination.
 Splenomegaly in isoimmunized fetuses correlates
to the severity of fetal anemia.
 In addition, splenomegaly in utero has been
reported due to viral infection.

56. Masses and Other Organ
Abnormalities
1.abnormally enlarged or infiltrated viscera or
2.the presence or development of an abnormal
structure.Hepatosplenomegaly
•viral infection,
• fetal hydrops
• glycogen or lysosomal
storage disorders,
• Beckwith-Wiedemann
syndrome,
•the presentation in utero of
anemia or hematologic
malignancy
Isolated hepatomegaly
• increased right heart
pressure
•repository for metastatic
disease, such as
neuroblastoma

57. Intraperitoneal Cystic
Masses in the Fetus
Intraperitoneal Solid Masses
in the Fetus
 Gastrointestinal tract: duplication,
meconium pseudocyst,
segmental dilatation of the ileum
(ileal dysgenesis)
 Biliary: choledochal cyst
 Hepatic: epithelial cyst,
mesenchymal hamartoma,
vascular malformation
 Splenic: congenital epithelial cyst,
epidermoid
 Lymphatic: mesenteric cyst,
mesenteric lymphangiomatosis
 Ovarian: follicular cyst, torsion
(late), teratoma
 Hepatic: hepatoblastoma,
hemangioendothelioma,
rapidly involuting congenital
hemangioma, torsion of
accessory lobe,
mesenchymal hamartoma,
teratoma, infarction
 Splenic: torsion
 Ovarian: torsion (early),
teratoma
 Pulmonary:
infradiaphragmatic
sequestration