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Ultrasound EvaluationOf the Fetal AbdomenUltrasound EvaluationOf the Fetal Abdomen
Fetal Abdomen
Of the Fetal AbdomenOf the Fetal Abdomen
Director of Ultrasound Research & Education
Geisinger Medical Center
Danville, Pennsylvania
Mani Montazemi, RDMS
Current Official Practice GuidelineCurrent Official Practice Guideline
• Abdomen
– Anterior abdominal wall
– Cord insertion
Stomach
• Abdomen
– Anterior abdominal wall
– Cord insertion
Stomach
Fetal Abdomen
– Stomach• Presence, size, situs
– Kidneys
– Bladder
– Number of umbilical cord vessels
– Stomach• Presence, size, situs
– Kidneys
– Bladder
– Number of umbilical cord vessels
Scanning Tips Scanning Tips
Fetal Abdomen
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Fetal StomachFetal Stomach
• Wide range of shapes– Round to oval to kidney-shaped
• Wide range of sizes– 4mm to 4cm
• Wide range of shapes– Round to oval to kidney-shaped
• Wide range of sizes– 4mm to 4cm
Fetal Abdomen
• Variable filling and emptying– Based on fetal swallowing and peristalsis
• Variable filling and emptying– Based on fetal swallowing and peristalsis
Non-visualization of the StomachNon-visualization of the Stomach
• < 19 wks, 50% ABNL
• > 19 wks, 100% ABNL
• < 19 wks, 50% ABNL
• > 19 wks, 100% ABNL
Fetal Abdomen
Esophageal AtresiaEsophageal Atresia
Fetal Abdomen
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Esophageal AtresiaEsophageal Atresia
• Incidence – 1 in 2500 to 4000 live births
• Overall detection rate – only 50%– Most of the polyhydramnios occur after 24 weeks
S ll h b bbl ld b di i d b i
• Incidence – 1 in 2500 to 4000 live births
• Overall detection rate – only 50%– Most of the polyhydramnios occur after 24 weeks
S ll h b bbl ld b di i d b i
Fetal Abdomen
– Small stomach bubble could be dismissed as being normal
– Small stomach bubble could be dismissed as being normal
Esophageal AtresiaEsophageal Atresia
• Small stomach depend on the type of esophageal atresia
• 5 types - most common with
• Small stomach depend on the type of esophageal atresia
• 5 types - most common with
Fetal Abdomen
yptracheoesophageal fistula– Fluid may cross the fistula
– Gastric secretions may accumulate
yptracheoesophageal fistula– Fluid may cross the fistula
– Gastric secretions may accumulate
Esophageal AtresiaEsophageal Atresia
• High incidence of additional anomalies > 50%– Cardiac, other GI, GU track,
CNS, Facial, skeletal, T18/21
• 40 % have IUGR
• High incidence of additional anomalies > 50%– Cardiac, other GI, GU track,
CNS, Facial, skeletal, T18/21
• 40 % have IUGR
Fetal Abdomen
• Incidence three times higher in twins
• Classic findings– Polyhydramnios
– Absent or small stomach bubble
• Incidence three times higher in twins
• Classic findings– Polyhydramnios
– Absent or small stomach bubble
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Non-visualization or Always Small Stomach (< 1cm)
Non-visualization or Always Small Stomach (< 1cm)
Causes:• High Gastrointestinal obstruction
– Mouth to esophagus
• Narrow/compressed chest
Causes:• High Gastrointestinal obstruction
– Mouth to esophagus
• Narrow/compressed chest
Fetal Abdomen
• Narrow/compressed chest
• Thoracic or neck mass
• Swallowing disorders
• Defect or mass in the fetal mouth (clefts)
• Severe neurologic or muscular abnormalities
• Narrow/compressed chest
• Thoracic or neck mass
• Swallowing disorders
• Defect or mass in the fetal mouth (clefts)
• Severe neurologic or muscular abnormalities
What do you see?What do you see?
Fetal Abdomen
Duodenal ObstructionDuodenal Obstruction
Fetal Abdomen
Large, obstructed stomach and a distended proximal duodenumLarge, obstructed stomach and a distended proximal duodenum
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Duodenal ObstructionDuodenal Obstruction
• Two cystic structures in the abdomen that communicate with each other– Classic “double bubble”
• Two cystic structures in the abdomen that communicate with each other– Classic “double bubble”
Fetal Abdomen
Duodenal ObstructionDuodenal Obstruction
• Can be seen as early as 22 weeks, usually it’s not apparent up until 29-32 weeks
• Polyhydramnios after 24 weeksDetection rate only 50%
• Can be seen as early as 22 weeks, usually it’s not apparent up until 29-32 weeks
• Polyhydramnios after 24 weeksDetection rate only 50%
Fetal Abdomen
– Detection rate = only 50%
• Associated with a 30% incidence of trisomy 21
• Associated with VACTERL complex
– Detection rate = only 50%
• Associated with a 30% incidence of trisomy 21
• Associated with VACTERL complex
VACTERL ComplexVACTERL Complex
Vertebral defects
Anal atresia
Cardiac defects
Vertebral defects
Anal atresia
Cardiac defects
Fetal Abdomen
Tracheoesophageal fistula
Esophageal atresia
Renal anomalies
Limb defects
Tracheoesophageal fistula
Esophageal atresia
Renal anomalies
Limb defects
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Duodenal ObstructionMajority of cases are due to mechanical problems
Duodenal ObstructionMajority of cases are due to mechanical problems
• Intrinsic causes – structural abnormalities
– Atresia (42%) • half of all duodenal atresias occur with Down syndrome, although
conversely, few cases of Down syndrome have duodenal atresia
Diaphragmatic web (10%)
• Intrinsic causes – structural abnormalities
– Atresia (42%) • half of all duodenal atresias occur with Down syndrome, although
conversely, few cases of Down syndrome have duodenal atresia
Diaphragmatic web (10%)
Fetal Abdomen
– Diaphragmatic web (10%)
– Stenosis (38%)
• Extrinsic causes – external cause
– Annular pancreas
– Malrotation
– Ladd’s bands
– Diaphragmatic web (10%)
– Stenosis (38%)
• Extrinsic causes – external cause
– Annular pancreas
– Malrotation
– Ladd’s bands
Duodenal ObstructionDuodenal Obstruction
• Prognosis is dependent upon whether other anomalies are present and their severity
• Prognosis is dependent upon whether other anomalies are present and their severity
Fetal Abdomen
Polyhydramnios is a constant feature in all intestinal atresiaPolyhydramnios is a constant feature in all intestinal atresia
Fetal Abdomen
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Ventral Wall DefectsVentral Wall Defects
Omphalocele– Central defect– Associated anomalies are common– High risk of aneuploidy
Omphalocele– Central defect– Associated anomalies are common– High risk of aneuploidy
Gastroschisis– Periumbilical defect– Associated anomalies are uncommon– Little to no risk of aneuploidy– High rate of bowel related
complications
Gastroschisis– Periumbilical defect– Associated anomalies are uncommon– Little to no risk of aneuploidy– High rate of bowel related
complications
Fetal Abdomen
complications– Associated with substance abuse &
medications
complications– Associated with substance abuse &
medications
OmphaloceleOmphalocele
Fetal Abdomen
• Herniation of intraabdominal contents into the base of the cord
• ALWAYS covered by a membrane
OmphaloceleOmphalocele
• Umbilical cord inserts onto membrane– In large defects may be displaced eccentrically
• The herniated bowel is NOT directly exposed to amniotic fluid
• Umbilical cord inserts onto membrane– In large defects may be displaced eccentrically
• The herniated bowel is NOT directly exposed to amniotic fluid
Fetal Abdomen
• Bowel usually does not thicken or dilate• Bowel usually does not thicken or dilate
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Is This an Omphalocele?Is This an Omphalocele?
Fetal Abdomen
Pseudo-OmphalocelePseudo-Omphalocele
Fetal Abdomen
Caused by scanning oblique or by excessive transducer pressureCaused by scanning oblique or by excessive transducer pressure
OmphaloceleCan be a small or large wall defect
OmphaloceleCan be a small or large wall defect
Fetal Abdomen
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OmphaloceleOmphalocele
• Small– Failure of normal midgut rotation
– Cord midpositioned
Us all contains onl bo el
• Small– Failure of normal midgut rotation
– Cord midpositioned
Us all contains onl bo el
Fetal Abdomen
– Usually contains only bowel
– Associated with chromosomal anomalies
– Usually contains only bowel
– Associated with chromosomal anomalies
OmphaloceleOmphalocele
• Large– Failure of anterior abdominal
wall closure
– Cord eccentric
• Large– Failure of anterior abdominal
wall closure
– Cord eccentric
Fetal Abdomen
Cord eccentric
– May contain organs
– Scoliosis
– Associated with structural anomalies
Cord eccentric
– May contain organs
– Scoliosis
– Associated with structural anomalies
OmphaloceleOmphalocele
Measurements of AC inaccurate and should
Fetal Abdomen
inaccurate and should be excluded from
biometric calculations
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OmphaloceleOmphalocele
• IUGR has been reported in 20% of patients
• 50% have associated anomalies (20% cardiac)
• 30% are associated with trisomy 13 & 18
• IUGR has been reported in 20% of patients
• 50% have associated anomalies (20% cardiac)
• 30% are associated with trisomy 13 & 18
Fetal Abdomen
• Elevated maternal serum alpha-fetoprotein (70%)• Elevated maternal serum alpha-fetoprotein (70%)
OmphaloceleOmphalocele
• Omphalocele and cord cyst may co-exist– Whartons jelly cyst – mucoid degeneration of Wharton Jelly
– Allantoic cyst – always near insertion site
– Omphalomesenteric duct cyst – associated with intraabdominal
• Omphalocele and cord cyst may co-exist– Whartons jelly cyst – mucoid degeneration of Wharton Jelly
– Allantoic cyst – always near insertion site
– Omphalomesenteric duct cyst – associated with intraabdominal
Fetal AbdomenJane J.K. Burns, RDMS
mesenteric cystsmesenteric cysts
Diagnostic ChallengeDiagnostic Challenge
Separate from but contiguous with the bladder
Fetal Abdomen
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Patent Urachus With Allantoic CystPatent Urachus With Allantoic Cyst
Urachus is an embryological remnant of the allantois which runs from the apex of the bladder
through the umbilical ring to terminate in the proximal umbilical cord
Fetal Abdomen
Umbilical Cord
Allantoic Stalk
Yolk Stalk
Cloaca
A Ruptured OmphaloceleCan Resemble Gastroschisis
A Ruptured OmphaloceleCan Resemble Gastroschisis
Fetal Abdomen
Omphalocele @11 Weeks ?Omphalocele @11 Weeks ?
Fetal Abdomen
Potential PitfallPotential Pitfall
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Normal Midgut HerniationNormal Midgut Herniation
• Fetal bowel normally herniates into the base of the umbilical cord at approx. the 7-8 weeks MA
• Detected sonographically from 9 11 wks
• Fetal bowel normally herniates into the base of the umbilical cord at approx. the 7-8 weeks MA
• Detected sonographically from 9 11 wks
Fetal Abdomen
• Detected sonographically from 9-11 wks
• Should not be visible by 12 week
• Detected sonographically from 9-11 wks
• Should not be visible by 12 week
“Possible Anomaly”CRL > 44mm with persistent herniation
Maximum dimension of abdominal mass > 7mm
Normal Midgut HerniationNormal Midgut Herniation
• This appearance should not be mistaken for a ventral wall defect
• This appearance should not be mistaken for a ventral wall defect
Fetal Abdomen
Midgut (umbilical) herniation beyond the 12th week of gestation has to be considered pathological
Fetal Abdomen
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GastroschisisGastroschisis
Fetal Abdomen
Small defect to right of cord insertionNo membrane over bowel
GastroschisisGastroschisis
• Incidence is 1 in 3000 births– Varies considerably with
maternal age
– Strong association reported among younger patients
• Incidence is 1 in 3000 births– Varies considerably with
maternal age
– Strong association reported among younger patients
Fetal Abdomen
• Less likely for organ herniation
• Variable amounts of bowel herniated
• Bowel floats within amniotic fluid
• Less likely for organ herniation
• Variable amounts of bowel herniated
• Bowel floats within amniotic fluid
GastroschisisGastroschisis
• Hepatic herniation is less frequent with gastroschisis than with omphaloceles
• Hepatic herniation is less frequent with gastroschisis than with omphaloceles
Fetal Abdomen
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GastroschisisGastroschisis
• Small defect (2-4cm)• Small defect (2-4cm)
Fetal Abdomen
GastroschisisGastroschisis
• Associated anomalies in about < 10% of fetuses
• IUGR in up to 50%
• No chromosomal abnormalities
• Elevated maternal serum alpha fetoprotein (70%)
• Associated anomalies in about < 10% of fetuses
• IUGR in up to 50%
• No chromosomal abnormalities
• Elevated maternal serum alpha fetoprotein (70%)
Fetal Abdomen
• Elevated maternal serum alpha-fetoprotein (70%)• Elevated maternal serum alpha-fetoprotein (70%)
GastroschisisGastroschisis
• Oligohydramnios – More common than polyhydramnios
– Suggest fetal distress
• Oligohydramnios – More common than polyhydramnios
– Suggest fetal distress
Fetal Abdomen
• Polyhydramnios– Suggest bowel obstruction or atresia
• Polyhydramnios– Suggest bowel obstruction or atresia
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GastroschisisGastroschisis
• Marked bowel dilatation, which may be either external or internal to the abdominal cavity, suggests bowel obstruction and/or ischemia
• Marked bowel dilatation, which may be either external or internal to the abdominal cavity, suggests bowel obstruction and/or ischemia
Fetal Abdomen
GastroschisisGastroschisis
• Bowel can twist and cut off blood supply• Bowel can twist and cut off blood supply
Fetal Abdomen
GastroschisisGastroschisis
Fetal Abdomen
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GastroschisisGastroschisis
Fetal Abdomen
GastroschisisGastroschisis
Fetal Abdomen
Ectopic Cordis“Large omphalocele coming all the way to heart”
Ectopic Cordis“Large omphalocele coming all the way to heart”
• Rare malformation
• Protrusion of heart through chest wall
• Association - Pentalogy of Cantrell
• Rare malformation
• Protrusion of heart through chest wall
• Association - Pentalogy of Cantrell
Fetal Abdomen
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Pentalogy of CantrellPentalogy of Cantrell
A term used to describe the association of 5 anomalies:
1. Midline supraumbilical abdominal defect
2. Defect of the lower sternum
3 Defect of the diaphragmatic pericardium
A term used to describe the association of 5 anomalies:
1. Midline supraumbilical abdominal defect
2. Defect of the lower sternum
3 Defect of the diaphragmatic pericardium
Fetal Abdomen
3. Defect of the diaphragmatic pericardium
4. Anterior diaphragmatic hernia
5. Intracardiac abnormalities
3. Defect of the diaphragmatic pericardium
4. Anterior diaphragmatic hernia
5. Intracardiac abnormalities
Pentalogy of Cantrell – US FindingsPentalogy of Cantrell – US Findings
• Midline anterior wall defect usually upper abdomen
• Ectopic heart• Pericardial or pleural effusion
• Midline anterior wall defect usually upper abdomen
• Ectopic heart• Pericardial or pleural effusion
Fetal Abdomen
• Craniofacial anomalies• Ascites• Two vessel cord
• Craniofacial anomalies• Ascites• Two vessel cord
Limb-Body Wall ComplexLimb-Body Wall Complex
• Also known as “body stalk” anomaly
• Failure of ventral abdominal wall to close– Often left sided
• Also known as “body stalk” anomaly
• Failure of ventral abdominal wall to close– Often left sided
Fetal AbdomenJane J.K. Burns, RDMS
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Limb-Body Wall ComplexLimb-Body Wall Complex
• Abdominal organs lie in a sac outside the abdominal cavity
• Short or absent umbilical cord
• Fetus lies directly on placenta*
• Universally fatal
• Abdominal organs lie in a sac outside the abdominal cavity
• Short or absent umbilical cord
• Fetus lies directly on placenta*
• Universally fatal
Fetal Abdomen
Limb-Body Wall ComplexLimb-Body Wall Complex
• Amniotic bands attached broadly to the fetus & placenta
• Large thoraco-abdominal wall defect – no covering membrane
• Amniotic bands attached broadly to the fetus & placenta
• Large thoraco-abdominal wall defect – no covering membrane
Fetal AbdomenJane J.K. Burns, RDMS
no covering membrane
• Distorted body axis
no covering membrane
• Distorted body axis
Limb-Body Wall ComplexLimb-Body Wall Complex
• Severe scoliosis – prominent feature
• Limb defects common
• Complex array of multiple malformations
• Severe scoliosis – prominent feature
• Limb defects common
• Complex array of multiple malformations
Fetal Abdomen
– Craniofacial & Internal organ anomalies– Craniofacial & Internal organ anomalies
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Bladder & Cloacal ExstrophyBladder & Cloacal Exstrophy
• Failure of closure of lower abdominal wall resulting in exposed bladder
• Omphalocele• Absent bladder
• Failure of closure of lower abdominal wall resulting in exposed bladder
• Omphalocele• Absent bladder
Fetal Abdomen
• Imperforate anus• Spinal abnormalities• Malformation of the
genitalia• Single umbilical artery
• Imperforate anus• Spinal abnormalities• Malformation of the
genitalia• Single umbilical artery
Bladder ExstrophyBladder Exstrophy
• 2o to abnormal development of the cloacal membrane
• Incidence is 1:30,000 births
• Eversion & exteriorization of the pelvic viscera on the
• 2o to abnormal development of the cloacal membrane
• Incidence is 1:30,000 births
• Eversion & exteriorization of the pelvic viscera on the
Fetal Abdomen
the pelvic viscera on the abdominal surface– Inferiorly displaced umbilicus
– Widely separared pubic bones
the pelvic viscera on the abdominal surface– Inferiorly displaced umbilicus
– Widely separared pubic bones
Reports of T21 & 13
Bladder Exstrophy – US FindingsBladder Exstrophy – US Findings
• Non-visible bladder• Normal kidneys• Normal amniotic fluid
volume
• Non-visible bladder• Normal kidneys• Normal amniotic fluid
volume
Fetal Abdomen
• Low CI• Bulging mass
protruding from the lower abdominal wall
• Small penis • Splayed iliac bones
• Low CI• Bulging mass
protruding from the lower abdominal wall
• Small penis • Splayed iliac bones
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Cloacal ExstrophyCloacal ExstrophyOmphalocele & bladder extrophy with prolapsed ileum between the two bladder halves
Fetal Abdomen
Ventral Wall DefectsRelation to UmbilicusVentral Wall DefectsRelation to Umbilicus
• Above umbilicus– Consider pentalogy of cantrell
• At umbilicusC id hi i h l l
• Above umbilicus– Consider pentalogy of cantrell
• At umbilicusC id hi i h l l
Fetal Abdomen
– Consider gastroschisis or omphalocele
• Below umbilicus– Consider exstrophy of bladder or cloaca
• Difficult to tell because of size– Consider body stalk anomaly
– Consider gastroschisis or omphalocele
• Below umbilicus– Consider exstrophy of bladder or cloaca
• Difficult to tell because of size– Consider body stalk anomaly
Normal Appearance of BowelNormal Appearance of Bowel
• Amniotic fluid is swallowed & as it gets to the small bowel it mixes with bowel mucopolysaccharide
• Moves to the large bowel – water is resorbed, leaving meconium
• Amniotic fluid is swallowed & as it gets to the small bowel it mixes with bowel mucopolysaccharide
• Moves to the large bowel – water is resorbed, leaving meconium
Fetal Abdomen
• Meconium is expelled at birth
• If there is obstruction or if meconium is abnormally thick that wouldn’t pass it causes obstruction in the bowel – meconium ileus
• Meconium is expelled at birth
• If there is obstruction or if meconium is abnormally thick that wouldn’t pass it causes obstruction in the bowel – meconium ileus
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Normal Appearance of BowelNormal Appearance of Bowel
• Meconium– Variable in echogenicity (hypo to hyperechoic), can be
seen throughout the later part of pregnancy, particularly in late 3rd trimester
• Meconium– Variable in echogenicity (hypo to hyperechoic), can be
seen throughout the later part of pregnancy, particularly in late 3rd trimester
Fetal Abdomen
Hyperechoic BowelHyperechoic BowelWhat DoesWhat Does
Fetal Abdomen
What Does
That Mean?
What Does
That Mean?
Hyperechoic BowelHyperechoic Bowel
• Increased echogenicity of the mesentery and small bowel walls
• Increased echogenicity of the mesentery and small bowel walls
Fetal Abdomen
The bowel itself is not echogenic
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Hyperechoic BowelHyperechoic Bowel
• Often normal variant– Related to higher
frequency transducers and to images with greater contrast
• Often normal variant– Related to higher
frequency transducers and to images with greater contrast
Fetal Abdomen
greater contrastgreater contrast
Fetal Abdomen
Echogenic Fetal BowelEchogenic Fetal Bowel
• Abnormal if– > 4 cm in size
– May have mass effect
Homogeneo s or heterogeneo s
• Abnormal if– > 4 cm in size
– May have mass effect
Homogeneo s or heterogeneo s
Fetal Abdomen
– Homogeneous or heterogeneous
– Brightness > bone (femur, spine, iliacs)
– Homogeneous or heterogeneous
– Brightness > bone (femur, spine, iliacs)
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Echogenic Fetal BowelEchogenic Fetal Bowel
• Seen in association with:– Cystic fibrosis, trisomy 21, cytomegalovirus
(CMV), parvo virus (5th disease), GI obstruction and IUGR
• Seen in association with:– Cystic fibrosis, trisomy 21, cytomegalovirus
(CMV), parvo virus (5th disease), GI obstruction and IUGR
Fetal Abdomen
Echogenic BowelEchogenic Bowel
• Swallowed blood (intra-amniotic hemorrhage)• Swallowed blood (intra-amniotic hemorrhage)
Fetal Abdomen
4 days post-amniocentesis4 days post-amniocentesis
Meconium PeritonitisMeconium Peritonitis
• Leaking of bowel contents leading to an intense peritoneal reaction
• Leaking of bowel contents leading to an intense peritoneal reaction
Fetal Abdomen
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Meconium PeritonitisMeconium Peritonitis
• 50% have underlying bowel pathology• 50% have underlying bowel pathology
Fetal Abdomen
Meconium PeritonitisMeconium Peritonitis
• Calcifications 85%– Usually punctate, linear or clumped foci
• Calcifications 85%– Usually punctate, linear or clumped foci
Fetal Abdomen
Meconium PeritonitisMeconium Peritonitis
• Calcifications 85%– Usually punctate, linear or clumped foci
• Ascities 54%U ll l
• Calcifications 85%– Usually punctate, linear or clumped foci
• Ascities 54%U ll l
Fetal Abdomen
– Usually complex– Usually complex
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Meconium PeritonitisMeconium Peritonitis
• Calcifications 85%– Usually punctate, linear or clumped foci
• Ascities 54%U ll l
• Calcifications 85%– Usually punctate, linear or clumped foci
• Ascities 54%U ll l
Fetal Abdomen
– Usually complex
• Bowel dilatations 27%
– Usually complex
• Bowel dilatations 27%
Meconium PeritonitisMeconium Peritonitis
• Calcifications 85%– Usually punctate, linear or clumped foci
• Ascities 54%U ll l
• Calcifications 85%– Usually punctate, linear or clumped foci
• Ascities 54%U ll l
Fetal Abdomen
– Usually complex
• Bowel dilatations 27%
• Pseudocysts 14%
• Polyhydramnios 65%
– Usually complex
• Bowel dilatations 27%
• Pseudocysts 14%
• Polyhydramnios 65%
Meconium PeritonitisMeconium Peritonitis
• Calcifications can extend to thorax• Calcifications can extend to thorax
Fetal Abdomen
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Meconium PeritonitisMeconium Peritonitis
• Calcifications can extend to scrotal sac• Calcifications can extend to scrotal sac
Fetal Abdomen
Abdominal CalcificationsAbdominal Calcifications
• Infections: herpes, toxoplasmosis, cytomegalovirus
• Tumors: teratoma, hepatoblastoma, neuroblastoma
• Peritonitis: meconium leak
• Infarcted bowel
• Infections: herpes, toxoplasmosis, cytomegalovirus
• Tumors: teratoma, hepatoblastoma, neuroblastoma
• Peritonitis: meconium leak
• Infarcted bowel
Fetal Abdomen
• Infarcted bowel
• Gallstones
• Idiopathic
• Infarcted bowel
• Gallstones
• Idiopathic
Small & Large
Fetal Abdomen
Bowel ObstructionObstructions below the duodenum are even harder to diagnose
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Small Bowel ObstructionSmall Bowel Obstruction
• Jejunal & ileal obstruction is more common than duodenal obstruction!– Vascular injury
• Jejunal & ileal obstruction is more common than duodenal obstruction!– Vascular injury
Fetal Abdomen
• Small bowel loops can be seen specially in 3rd
trimester• Small bowel loops can be seen specially in 3rd
trimester
Small Bowel ObstructionSmall Bowel Obstruction
• They peristalsis and change in configuration
• Do not persist, and should not be >15 mm in length and 7 mm in diameter
• They peristalsis and change in configuration
• Do not persist, and should not be >15 mm in length and 7 mm in diameter
Fetal Abdomen
7 mm in diameter• Can rarely present as cyst
like mass• Polyhydramnios
– Timing & severity dependent on site of atresia
7 mm in diameter• Can rarely present as cyst
like mass• Polyhydramnios
– Timing & severity dependent on site of atresia
Small bowels are centrally locatedSmall bowels are centrally located
Small Bowel ObstructionSmall Bowel Obstruction
Causes:
• Intestinal atresia– Related to an in utero vascular accident
Causes:
• Intestinal atresia– Related to an in utero vascular accident
Fetal Abdomen
• Stenosis
• Volvulus
• Meconium ileus– In fetuses with cystic fibrosis
• Stenosis
• Volvulus
• Meconium ileus– In fetuses with cystic fibrosis
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PitfallsPitfalls
• Different processes can be mistaken for dilated small bowel– Cysts in an enlarged multicystic displastic kidney
Dilated tortuous ureter
• Different processes can be mistaken for dilated small bowel– Cysts in an enlarged multicystic displastic kidney
Dilated tortuous ureter
Fetal Abdomen
– Dilated tortuous ureter – Dilated tortuous ureter
Large Bowel ObstructionLarge Bowel Obstruction
• Normal large bowel < 20 mm diameter
• Rare - It occurs at the anal-rectal region
• Additional structural &
• Normal large bowel < 20 mm diameter
• Rare - It occurs at the anal-rectal region
• Additional structural &
Fetal Abdomen
chromosomal anomalies are very common (75%)– VACTERL & caudal regression
syndrome
Causes:• Atresia• Stenosis
chromosomal anomalies are very common (75%)– VACTERL & caudal regression
syndrome
Causes:• Atresia• Stenosis
Solid Abdominal MassesSolid Abdominal MassesMesoblastic nephroma Neuroblastoma Hepatoblastoma
Fetal AbdomenSubdiaphragmatic extralobar
pulmonary sequestration
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Fetal Abdomen
Abdominal CystsDifferential Diagnosis
Abdominal CystsDifferential Diagnosis
• RUQ– Hepatic/choledochal cyst
• LUQ– Splenic cyst
• PosteriorRenal cyst hydronephrosis
• RUQ– Hepatic/choledochal cyst
• LUQ– Splenic cyst
• PosteriorRenal cyst hydronephrosis
Fetal Abdomen
– Renal cyst, hydronephrosis
• Anterior/mid-abdomen– Mesenteric cyst, umbilical vein varix
• Lower abdomen– Ovarian cyst (but may migrate to mid-abdomen)– Ureterocele– Urachal cyst– Hydrometrocolpos
– Renal cyst, hydronephrosis
• Anterior/mid-abdomen– Mesenteric cyst, umbilical vein varix
• Lower abdomen– Ovarian cyst (but may migrate to mid-abdomen)– Ureterocele– Urachal cyst– Hydrometrocolpos
Diagnostic ChallengeDiagnostic Challenge
Fetal Abdomen
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Diagnostic ChallengeDiagnostic Challenge
Fetal Abdomen
There is Flow! Is it venous or arterial?There is Flow! Is it venous or arterial?
Fetal Abdomen
Umbilical Vein VarixUmbilical Vein Varix
• Focal dilatation of umbilical vein
• Usually intraabdominal but extrahepatic may occur in association with persistent right umbilical vein
• Focal dilatation of umbilical vein
• Usually intraabdominal but extrahepatic may occur in association with persistent right umbilical vein
Fetal Abdomen
umbilical vein
• It may also occur in free floating loops of cord
• Umbilical vein varix of intra-amniotic segment is rarer than intra-abdominal
umbilical vein
• It may also occur in free floating loops of cord
• Umbilical vein varix of intra-amniotic segment is rarer than intra-abdominal
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Umbilical Vein VarixUmbilical Vein Varix
• Focal dilatation of intra-abdominal portion
– Usually near cord insertion
– Abnormal if internal diameter > 9 mm or twice size of intrahepatic portion of vein
Normal size at week 20 is 3 4 mm with linear increase up
• Focal dilatation of intra-abdominal portion
– Usually near cord insertion
– Abnormal if internal diameter > 9 mm or twice size of intrahepatic portion of vein
Normal size at week 20 is 3 4 mm with linear increase up
Fetal Abdomen
– Normal size at week 20 is 3-4 mm with linear increase up to 8 mm at term
– Normal size at week 20 is 3-4 mm with linear increase up to 8 mm at term
Umbilical Vein VarixUmbilical Vein Varix
Fetal Abdomen
Umbilical Vein VarixUmbilical Vein Varix
• Can be associated with:– Chromosome abnl (T-21, 18, 9)
– Congenital malformations– Decreased growth
H d
• Can be associated with:– Chromosome abnl (T-21, 18, 9)
– Congenital malformations– Decreased growth
H d
Fetal Abdomen
– Hydrops– Thrombosis
• May be first manifestation of elevated venous pressure therefore may signify increased risk of cardiac decompensation
• As isolated finding: normal outcome
– Hydrops– Thrombosis
• May be first manifestation of elevated venous pressure therefore may signify increased risk of cardiac decompensation
• As isolated finding: normal outcome
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Choledochal CystCholedochal Cyst
• Cystic dilatation of the CBD
• Separate from gallbladder
• No communication with stomach
• Cystic dilatation of the CBD
• Separate from gallbladder
• No communication with stomach
Fetal Abdomen
Abdominal CystsAbdominal Cysts
Fetal Abdomen
Abdominal CystsAbdominal Cysts
• Lower abdomen – Female: think ovarian: may migrate/auto-amputate
• Torsion in ~ 40 % if > 5 cm
• Lower abdomen – Female: think ovarian: may migrate/auto-amputate
• Torsion in ~ 40 % if > 5 cm
Fetal Abdomen
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Thank YouThank You
Fetal Abdomen
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