Sonography of fetal GIT

Ultrasound Diagnosis of Anomalies of the Fetal GIT

“A Systematic Approach”

Professor Hassan Nasrat FRCS, FRCOG

www.hassannasrat.com

JUCOG November 2013

Thursday, November 28, 13

http://www.hassannasrat.com

http://www.hassannasrat.com

★Overlap Between Appearance Of Normal And Abnormal Fetal Bowel.

Challenges in Sonography of the Fetal GIT




The main differential feature of the gastrointestinal (GI)tract in comparison with other organ systems is that itsultrasound appearance varies significantly during preg-nancy and also, for some sites, in the course of the sameultrasound examination, due to the physiology of swal-lowing, stomach emptying, and intestinal peristalsis. It istherefore necessary to become acquainted with thewhole range of anatomic correlates. It should also beunderlined that the origin of a cystic or solid massdetected in the abdominal cavity can also be difficult toidentify with certainty. For example, a cystic anechoiclesion can correspond to very different diagnoses accord-ing to its site and the relationships with the adjacent vis-cera: enteric duplication cyst, mesenteric cyst, choledochalcyst, double bubble in duodenal atresia, adrenal hemor-rhage, renal cyst, or ovarian cyst. Finally, it shouldbe underlined that, as far as obstructive GI lesions areconcerned (duodenal atresia, esophageal atresia, ilealatresia, etc.), the dilatation of the tract proximal to theobstruction can become sonographically evident only inthe 3rd trimester.

Timing of examination. As already mentioned, theultrasound appearance of the various GI tracts changessignificantly with advancing gestational age. In the 3rdtrimester, the density of the intestinal content at the levelof the colon increases and becomes hypoechoic in com-parison with the intestinal walls. This allows identifica-tion of the whole course of the colon, from the cecum tothe rectum (Figure 7.1). It is also important to considerthat the sonographic echogenicity of the intestinal wallschanges significantly with the emission frequency ofthe transducer: higher frequencies (6–7 MHz) makethe interfaces between the solid intestinal walls and thefluid content much brighter, with a consequent overallincrease in intestinal echogenicity.

Ultrasound approach and scanning planes (views). Acomplete ultrasound assessment of the GI tract requiresa series of views targeted to the various segments thathave to be visualized, from the mouth to the rectum.Some of these views have already been described inChapters 3 and 6. To these views, those necessary toexplore the intra-abdominal intestinal tract, the liver,and the spleen should be added.

Cranial views (mouth, pharynx, and esophagus). Theseviews have already been described in Chapter 3, and thereader may refer to that chapter for full description.These views are summarized below:

•• lips: oblique view (Figure 7.2a)•• tongue/pharynx: axial view (Figure 7.2b)

Chapter 7Anomalies of the gastrointestinal

tract and abdominal wall

NORMAL ANATOMY OF THE GASTROINTESTINAL TRACTAND ABDOMINAL WALL: ULTRASOUND APPROACH,SCANNING PLANES, AND DIAGNOSTIC POTENTIAL

Figure 7.1 Axial view of the upper abdomen in a 35-week-old fetus.Note the dilatation of the colon with the haustra. This finding may beindicative of an obstruction or may be completely normal, as it happenedto be in this case.

207

07-Ultrasound 8015.qxd 3/27/2007 3:22 PM Page 207

Axial view of the upper abdomen in a 35-week-old fetus. Note the dilatation of the colon with the haustra. This finding may be indicative of an obstruction or may be normal,


★Appearance Varies Significantly During The Course Of Pregnancy And During The Course Of The Same Examination.


36 wks15 wks 24 wks



★Appearance Varies Significantly During The Course Of Pregnancy And During The Course Of The Same Examination.

★Difficulty To Identify The The Origin Of Abnormal Sonographic Signs E.g. Cystic Or Solid Mass.

★Obstructive Lesions Becomes Evident In The 3rd Trimester.



Haeusler MC, Berghold A, Stoll C, Barisic I, Clementi M, EUROSCAN Study Group Prenat Diagn. 2002;22(7):616.

Overall Esophageal Duodenal Small B. Large B. Anal Atresia

Prenatal Ultrasonographic Detection Of Gastrointestinal Obstruction: Results From 18 European Congenital Anomaly Registries.

EUROSCAN Study

34%

25%

52%

40%

29%

8%

34%


Ultrasound Diagnosis of Anomalies of the Fetal GIT

“A Systematic Approach”


✤Normal Sonographic Appearance of the GIT Tract.

✤Systemic Approach to Fetal GIT Sonography.

✤Sonographic Signs suggestive of Anomalies.


Physiologic Midgut Herniation

Physiologic Midgut Herination Between 9-11th Week Due To Rapid Growth Of The Intestine And Liver Beyond The Capacity Fo Of The Abdominal Cavity, Reduced By 12th Week


• The Fetal Esophagus Is Normally Collapsed And Typically Not Visualized.

• Swallowing Occurs By 11 To 14 Weeks Of Gestation. Phases Of Swallowing Can Occur At 20-30 Minutes.

Esophagus30 Wks

pharynx


Sagital Axial

Coronal Render


In First And Second Trimesters:

• Fluid In The Lumen After 13 Weeks. Peristalsis Can Be Observed As Early As 18 Weeks.

• The Colon Is Best Visualized After 24 Weeks. As Hypoechoic Regions Along The Periphery Of The Abdomen.

Bowel

Late Second and Third Trimesters:

• Increased echogenicity with accumulation of Meconium.

• Normal small bowel loops do not exceed 7 mm in diameter or 15 mm in length.

• The large colon can achieve a diameters up to 23 mm at term.

15 wks

25 wks

36 wks


Normal fetal bowel at 24 weeks of gestation.(A) T2w coronal image shows high signal fluid filled loops of bowel throughout the abdomen. Minimal low signal meconium can be seen in the pelvis.(B) T1w coronal image better demonstrates high signal meconium filling the rectosigmoid and descending colon.

Magnetic resonance images of normal fetal bowel


★Cranial Views: ( Mouth, Pharynx, And Esophagus).

★Abdominal Views ( Ileum, Jejunum, Colon, Abdominal Wall)

★Views Of GIT Related Organs ( Liver, Spleen).

Ultrasound Approach And Scanning Planes




★Related Intra-abdominal Organs ( Liver, Spleen).



Cranial Views ( Lips, Mouth, Pharynx)

Cranial views and related malformations. We describeagain the cranial views in order to underline the normalultrasound appearance of the esophagus. This mayappear, in its proximal part, as a pouch full of amnioticfluid, especially if the fetus has just swallowed. The two-dimensional (2D) sagittal view and the 3D volume con-trast imaging (VCI-C)-derived coronal view of thethorax may allow the thoracic esophageal tract to be rec-ognized as a thin prevertebral anechoic structure, whenfilled with some amniotic fluid (Figure 7.3). In this situa-tion, the thoracic tract of the esophagus may resemble avessel. Power or color Doppler may be used to excludeits vascular origin. Also on the 4-chamber view, thecross-sectional appearance of the esophagus distendedby some amniotic fluid may be mistaken for that of anabnormal vessel, as in abnormal pulmonary or systemic(axygos continuation) venous return. This artifact isshown in Figure 7.3d. Some authors have also describedthe sonographic aspect of the esophagus when emptyas ‘two or more parallel echogenic lines’.1 Finally, itshould be underlined that also the esophagus, like mostthoracic anatomic structures, may benefit from a 3Dapproach. In particular, the coronal thoracic planeimaged with VCI-C is advantageous for assessment ofthoracic esophagus (Figure 7.3b).

Axial view of the abdomen and related malformations(Figure 7.4a). This represents the classic view for mea-surement of the abdominal circumference. On this view,the following structures of the GI tract can be recog-nized: on the left, the gastric bubble, appearing as a well-defined, anechoic, round or oval area (although, in somecircumstances, particulate matter can be seen floating init); on the right, most of the liver, which shows a weakly

hyperechogenic echostructure, and the intrahepatic tractof the umbilical vein, anechoic with evident walls.Nomograms of the normal gastric biometry versus gesta-tional age are available in the literature2 (see theAppendix). The GI anomalies that can be recognized onthis view are as follows:

•• esophageal atresia: non-visualization of the gastricbubble

•• duodenal atresia/stenosis: double bubble•• hepatomegaly: increased liver volume•• splenomegaly: increased splenic volume

Non-visualization of the gastric bubble (Figure 7.7).Following the spirit of this book – from ultrasound signto diagnosis – we believe it useful to define a diagnosticalgorithm to apply in the case of non-visualization ofthe gastric bubble. The importance of this algorithmlies in the fact that the stomach may be impossible todisplay on ultrasound not only in case of esophagealatresia but also in a heterogeneous group of other con-ditions. First, it has to be excluded that the stomach isnot visible because it has just emptied in the duodenumfollowing its physiologic emptying cycle. To confirm orexclude this frequent cause of non-visualization of thegastric bubble, it is sufficient to rescan the woman after60–80 minutes; in fact, the physiologic filling–empty-ing cycle of the stomach lasts about 50–60 minutes.3 Incases of severe oligohydramnios from premature rup-ture of membranes and, to a lesser extent, from severefetal growth restriction (FGR), the stomach could beempty, since the amount of residual amniotic fluid maynot be enough to ensure a sufficient filling to be recog-nizable on ultrasound. Other very severe conditions

•• neck (hypopharynx and esophagus): sagittal view(Figure 7.3a,b)

•• thorax (esophagus): sagittal view (Figure 7.3c)

•• thorax (esophagus): axial 4-chamber view(Figure 7.3d)

Abdominal views (ileus, jejunum, colon, liver,spleen, and abdominal wall). The scanning viewsare:

•• axial view of the upper abdomen: stomach and righthepatic lobe (Figure 7.4a)

•• axial view of the lower abdomen: small bowel(Figure 7.4b)

•• midsagittal view of the abdomen: cord insertion andrectal pouch in the pelvis (Figure 7.5a, b)

•• left parasagittal view: spleen•• right parasagittal view: right hepatic lobe (Figure 7.5c)•• coronal view (VCI-C): general approach (Figure 7.6)

208 ULTRASOUND OF CONGENITAL FETAL ANOMALIES

Figure 7.2 Cranial views for the assessment of the upper gastrointesti-nal tract (mouth and pharynx). (a) Oblique view of the lips. (b) Axialview of the mouth with the tongue (T) and, behind, the oropharynx(arrows).

GASTROINTENSTINAL TRACT AND ABDOMINAL WALLANOMALIES BY SCANNING VIEW

a b


Cranial views and related malformations. We describeagain the cranial views in order to underline the normalultrasound appearance of the esophagus. This mayappear, in its proximal part, as a pouch full of amnioticfluid, especially if the fetus has just swallowed. The two-dimensional (2D) sagittal view and the 3D volume con-trast imaging (VCI-C)-derived coronal view of thethorax may allow the thoracic esophageal tract to be rec-ognized as a thin prevertebral anechoic structure, whenfilled with some amniotic fluid (Figure 7.3). In this situa-tion, the thoracic tract of the esophagus may resemble avessel. Power or color Doppler may be used to excludeits vascular origin. Also on the 4-chamber view, thecross-sectional appearance of the esophagus distendedby some amniotic fluid may be mistaken for that of anabnormal vessel, as in abnormal pulmonary or systemic(axygos continuation) venous return. This artifact isshown in Figure 7.3d. Some authors have also describedthe sonographic aspect of the esophagus when emptyas ‘two or more parallel echogenic lines’.1 Finally, itshould be underlined that also the esophagus, like mostthoracic anatomic structures, may benefit from a 3Dapproach. In particular, the coronal thoracic planeimaged with VCI-C is advantageous for assessment ofthoracic esophagus (Figure 7.3b).

Axial view of the abdomen and related malformations(Figure 7.4a). This represents the classic view for mea-surement of the abdominal circumference. On this view,the following structures of the GI tract can be recog-nized: on the left, the gastric bubble, appearing as a well-defined, anechoic, round or oval area (although, in somecircumstances, particulate matter can be seen floating init); on the right, most of the liver, which shows a weakly

hyperechogenic echostructure, and the intrahepatic tractof the umbilical vein, anechoic with evident walls.Nomograms of the normal gastric biometry versus gesta-tional age are available in the literature2 (see theAppendix). The GI anomalies that can be recognized onthis view are as follows:

•• esophageal atresia: non-visualization of the gastricbubble

•• duodenal atresia/stenosis: double bubble•• hepatomegaly: increased liver volume•• splenomegaly: increased splenic volume

Non-visualization of the gastric bubble (Figure 7.7).Following the spirit of this book – from ultrasound signto diagnosis – we believe it useful to define a diagnosticalgorithm to apply in the case of non-visualization ofthe gastric bubble. The importance of this algorithmlies in the fact that the stomach may be impossible todisplay on ultrasound not only in case of esophagealatresia but also in a heterogeneous group of other con-ditions. First, it has to be excluded that the stomach isnot visible because it has just emptied in the duodenumfollowing its physiologic emptying cycle. To confirm orexclude this frequent cause of non-visualization of thegastric bubble, it is sufficient to rescan the woman after60–80 minutes; in fact, the physiologic filling–empty-ing cycle of the stomach lasts about 50–60 minutes.3 Incases of severe oligohydramnios from premature rup-ture of membranes and, to a lesser extent, from severefetal growth restriction (FGR), the stomach could beempty, since the amount of residual amniotic fluid maynot be enough to ensure a sufficient filling to be recog-nizable on ultrasound. Other very severe conditions

•• neck (hypopharynx and esophagus): sagittal view(Figure 7.3a,b)

•• thorax (esophagus): sagittal view (Figure 7.3c)

•• thorax (esophagus): axial 4-chamber view(Figure 7.3d)

Abdominal views (ileus, jejunum, colon, liver,spleen, and abdominal wall). The scanning viewsare:

•• axial view of the upper abdomen: stomach and righthepatic lobe (Figure 7.4a)

•• axial view of the lower abdomen: small bowel(Figure 7.4b)

•• midsagittal view of the abdomen: cord insertion andrectal pouch in the pelvis (Figure 7.5a, b)

•• left parasagittal view: spleen•• right parasagittal view: right hepatic lobe (Figure 7.5c)•• coronal view (VCI-C): general approach (Figure 7.6)


Figure 7.2 Cranial views for the assessment of the upper gastrointesti-nal tract (mouth and pharynx). (a) Oblique view of the lips. (b) Axialview of the mouth with the tongue (T) and, behind, the oropharynx(arrows).

GASTROINTENSTINAL TRACT AND ABDOMINAL WALLANOMALIES BY SCANNING VIEW

a b


Oblique View Of The Lips

Axial View Of The Mouth With The Tongue (T) And, Behind, The

Oropharynx (arrows)Thursday, November 28, 13

Neck (hypopharynx And Esophagus)

Sagittal View

that may result in non-visualization of the stomachbubble are the fetal akinesia deformation sequence(FADS) and the other neuroarthrogryposes (Chapter10): here the swallowing reflex is blocked due to con-tracture of the masseters and the pharyngeal muscles.This leads to polyhydramnios on the one hand and tonon-visualization of the stomach on the other. In addi-tion, it seems that the increased incidence of non-visu-alization of the gastric bubble reported in cases ofcomplex facial clefts is due to the fact that the palatalanomaly renders deglutition ineffective. The stomachmay also be impossible to visualize in its usual positiondue to migration, as in left-sided congenital diaphrag-matic hernia (CDH). Finally, there is an extremely rarecongenital anomaly, microgastria, which represents anarrest in the development of the stomach. A diagnosticflow-chart to be applied in the case of non-visualiza-tion of the stomach is shown in Figure 7.7.

Axial view of the lower abdomen and related malforma-tions (Figure 7.4b). On this view, which is parallel andcaudal to the axial view discussed above, the smallbowel, the transverse colon, and, in some cases, the cordinsertion can be recognized. With minor tilting of thetransducer, the gallbladder can also be demonstrated.The ileal loops appear isoechoic or weakly hyperechoicin comparison with the relatively hypoechoic colon. Thegallbladder has a variable shape, as in postnatal life, andusually has an anechoic content. It should be underlinedthat the rare recognition of apparent sludge in the fetalgallbladder in the 3rd trimester should not be consideredto be synonymous with gallstones. The major anomaliesthat may be detected on this view are as follows:

•• Omphalocele: defect of the anterior abdominal wall,containing bowel and /or liver, which bulges from thecord insertion area

ANOMALIES OF THE GASTROINTESTINAL TRACT AND ABDOMINAL WALL 209

Figure 7.3 Ultrasound views of the thoracic esophagus. (a) Sagittalview of the fetal neck, showing the course of the esophagus (arrow-heads), which is temporarily dilated by the swallowing of some amni-otic fluid. (b) The same region (arrowheads)is shown in the coronalview, using three-dimensional volume contrast imaging (VCI-C). (c)More caudally, the parasagittal view demonstrates the esophagusbehind the left atrium (arrowheads). (d) The same region, on the 4-chamber view: on this view, it is necessary to differentiate the tempo-rary dilatation of the esophagus (arrowhead) from an abnormalvenous return (systemic or pulmonary). If the anechoic area is due toesophageal dilatation, it disappears after a few minutes; in addition,the use of color/power Doppler may easily confirm or rule out a car-diovascular anomaly.

Figure 7.4 Axial abdominal views (stomach, bowel, liver, andspleen). (a) Axial view of the upper abdomen: the stomach is visible onthe left, the right hepatic lobe on the right, and the intrahepatic tract ofthe umbilical vein on the midline. (b) Axial view of the lower abdomen(ventral approach): the bowel (ileus and jejunum) and a small segmentof the umbilical vein (arrow) are visible.

a b

c d

a

b








a b

c d

a

b


The Same Region Shown In The Coronal View, Using Three-dimensional Volume Contrast Imaging.

The Esophagus (The Neck)Sagital And Coronal Views








a b

c d

a

b








a b

c d

a

b


The Esophagus (The Chest)Sagital And Axial Views

Esophagus Sagittal View

Axial 4-chamber View




★Related Intra-abdominal Organs ( Liver, Spleen).



Axial View Of The Upper Abdomen:

Stomach And Right Hepatic Lobe

Axial View Of The Lower Abdomen: Small Bowel

Midsagittal View:The Cord Insertion And

Rectal Pouch In The Pelvis

Left Para Sagittal View:

The Stomach & Spleen

Right Para Sagittal View:Rt Hepatic Lobe

Coronal View3 D Imaging








a b

c d

a

b


Axial View Of The Upper Abdomen: On The Left, The Gastric Bubble.On The Right, Most Of The Liver, Appears As A Weakly Hyperechogenic Structure.The Intrahepatic Tract Of The Umbilical Vein.

Axial View Of The Upper Abdomen: Stomach And Right Hepatic Lobe








a b

c d

a

b


Axial View Of The Lower Abdomen (ventral Approach)The Bowel (ileus And Jejunum) And A Small Segment Of The Umbilical Vein (arrow) Are

Visible.

Axial View Of The Lower Abdomen: Small Bowel


•• Gastroschisis: ileal loops floating freely in the amnioticfluid

•• Choledochal cyst: an anechoic cystic structure justbelow the liver

•• Small-bowel atresia: severe dilatation of ileal loopsproximal to the atretic tract

•• Meconium ileus: diffuse hyperechogenicities and cal-cifications within the intestinal lumen, sometimesassociated with small-bowel obstruction

Midsagittal view of the abdomen and related malfor-mations (Figure 7.5 a,b). This view allows one toassess the contour of the abdominal wall and the cord

insertion site; in addition, in the pelvis, it is possible toidentify the rectal pouch behind the bladder: it appearsas a hypoechoic structure that becomes particularlyevident in the 3rd trimester, when it is full with meco-nium. In this view abdominal wall defects, namelyomphalocele, gastroschisis, and in some cases, bladderand cloacal extrophy, can be detected.

Left parasagittal view and related malformations. Thisview is parallel and to the left of the midsagittal one.On this view, the stomach and the spleen can be seen,although the spleen is very difficult to visualize since it liesbelow the shadows of the lower ribs and has an echoden-sity that is rather similar to that of the liver and the lung.With color/power Doppler, using an axial approach, it ispossible to locate the vascular hilum of the spleen. Nomo-grams reporting the two maximum splenic diameters ver-sus gestational age have been published and are reported inthe Appendix. However, it should be noted that, whenconspicuous, such as in the case of severe cytomegalovirus(CMV) infection, splenomegaly cannot be missed.

Right parasagittal view and related malformations(Figure 7.5c). If the transducer is moved contralaterally,towards the right part of the abdomen, the right lobe ofthe liver comes into view, appearing as a solid, weakly


Figure 7.5 Other abdominal views (liver, abdominal wall, andrectum). (a) Midsagittal view of the abdomen: the cord insertion,highlighted by power Doppler, and part of the small bowel (arrow-head) are visible. (b) With small movements of the transducer, it ispossible to visualize, in the pelvis, the bladder and, behind it, the rectalpouch (arrow). (c) Right parasagittal view of the abdomen: the righthepatic lobe (Li), just below the hypoechoic layer of the diaphragm(arrowheads) and some ileal loops are visible. RL, right lung.

Figure 7.6 Coronal view of thorax and abdomen: volume contrastimaging (VCI-C): 3D ultrasound allows reconstruction of the coronalview of the fetal body, which is rather difficult to obtain with 2D ultra-sound. On this view, the spatial relationships among the thoracic andthe abdominal viscera can be studied in detail. The diaphragm appearsas a hypoechoic layer (arrowheads). In the thorax, the right lung (RL,right lung) and the heart (H), in the left hemithorax, are clearly dis-played (the left lung is hidden by the heart). Below the diaphragm, theliver is visible, with its left lobe (LL, left lobe) above the gastric bubble(St) and the right lobe (RL); the arrow indicates the gallbladder.

a

b

c













a

b

c


The Rectal Pouch Appears Filled With Hypoechoic

Meconium Appears In The Pelvis Behind The Bladder

Small Part Of The Small Bowel

Midsagittal View:The Cord Insertion And Rectal Pouch In The Pelvis

Mid-sagital View (Ventral) Showing Cord Insertion And Rectal Pouch Of The Pelvis Thursday, November 28, 13

Rt. Para-Sagital View Showing The Rt. Lung, The Diaphragm, Rt Hepatic Lobe And Bowel Loops

Right Para Sagittal View:Rt Hepatic Lobe












a

b

c














a

b

c


The Right Lung

The Diaphragm

The Gall Bladder

Coronal View3 D Imaging

Coronal View Showing Topography Of Abdominal OrgansThursday, November 28, 13

Ultrasound Views Used In Examination Of Fetal Abdomen And Related Malformations

Axial View Of The Upper Abdomen

Axial View Of The Lower Abdomen

Mid-Sagital View

Right Para-sagital

Left Para-sagital

★Esophageal Atresia: ★Duodenal Atresia/stenosis: ★Hepatomegaly: ★Splenomegaly:

★Omphalocele: ★Gastroschisis: ★Choledochal Cyst: ★Small-bowel Atresia: ★Meconium Ileus:

★Omphalocele, Gastroschisis.★In Some Cases, Bladder And Cloacal Extrophy.

★RL, Right Lung. ★Diaphragm (arrowheads).★The Right Hepatic Lobe (Li).★Some Ileal Loops.

★The Stomach And The Spleen

★Esophageal Atresia: ★Duodenal Atresia /stenosis: ★Hepatomegaly: ★Choledochal Cyst: ★Enteric Duplication Cyst: ★Splenomegaly: ★Small-bowel Atresia: ★Meconium Ileus:

Coronal View


Ultrasound Signs Suggestive Of GIT Anomalies

✦Non-visualization Of The Gastric Bubble.✦Cystic Lesions .

✦Dilated Small Bowel.

✦Dilated Large Bowel.✦“Echogenic Bowel”.

✦Large Liver / Spleen.✦Abdominal Wall Defects


✦Non-visualization Of The Gastric Bubble.


Non Visualization of the Stomach

Rule out physiologic Emptying.



Normal Amniotic Fluid Absent Amniotic Fluid





•PROM

•Sever FGR

•Bilateral Renal Agenesis





•PROM

•Sever FGR


Associated Anomalies?





•PROM

•Sever FGR



Yes





•PROM

•Sever FGR



Yes Stomach in Thorax

Contractures

Facia Cleftings

Lt. Sided Diaphragmatic Hernia





•PROM

•Sever FGR




Contractures

Facia Cleftings


FADSfetal akinesia deformation

sequence





•PROM

•Sever FGR




Contractures

Facia Cleftings



sequence

Cleft Lip/plalte





•PROM

•Sever FGR



Yes

No

Stomach in Thorax

Contractures

Facia Cleftings

Esophageal Atresia



sequence

Cleft Lip/plalte



Incidence: 1 /2500–1 /4000 Live Births.

Esophageal Atresia


Associated Anomalies:

✦Chromosomal Anomalies: (20–44%): Trisomies 21 And, To A Lesser Extent, 18.

✦Non-chromosomal Syndromes: 50 % Have Additional Anomalies. Cardiac Malformations (25%). VACTERL (vertebral, Anal Atresia, Cardiac, Tracheoesophageal Fistula, Renal, Limb)


Etiology:Failure Of Division Of The Primitive Foregut Into The Ventral Tracheobronchial Part And The Dorsal Digestive Part Around About 8 Weeks Of Gestation.

Esophageal Atresia


With a distal Fistula(85 %)

5 Types of Esophageal atresia

without fistula (8 %)

with fistula to both esophageal

segments (<1 %)

Isolated fistula No esophageal atresia

(<4 %)

With proximal Fistula

(1%)

The Presence Of TE Fistula Is Responsible For The Poor Prenatal Diagnosis Of Esophageal Atresia.

Proximal Esoph.

Distal Esoph.

Trachea


Diagnostic Triad (8-10 % In Cases):

✦Polyhydramnios: Becomes Evident In The Late 2nd Trimester.

✦Absent/Small Stomach: In 85% Of Cases It Is Visible.

✦The “Pouch Sign”: Dilated Proximal Esophageal Pouch.

Ultrasound Findings

The Overall Detection Rate, Considering All Possible Signs Of Esophageal Atresia Is In The Range Of 24–42%


Definition. In esophageal atresia, the communicationbetween the proximal and the distal tract of the esophagusis absent, due to a lack of development of the intermediateesophageal portion, mainly because of an interruption ofthe blood supply during organogenesis. Esophageal atre-sia can occur as an isolated anomaly (10% of cases) or,much more frequently, be associated with a tracheo-esophageal (TE) fistula (90% of cases), i.e., an abnormalcommunication between the trachea and the distalesophageal stump. The frequent association with TE fis-tula is responsible for the extremely low intrauterinedetection rate: this is due to the fact that some amnioticfluid may actually reach the distal esophagus and eventu-ally fill the stomach, just by transiting through the fistula.If this is the case, then ultrasound diagnosis becomesvirtually impossible, being based on the detection of a con-stantly small gastric bubble. Anatomically, five types ofesophageal atresia are recognized, according to the Grossclassification,4 on the base of the anatomy and site of theTE fistula:

•• type A: no fistula (8% of cases)•• type B: fistula with proximal stump (1%)•• type C: fistula with distal stump (88%)•• type D: double fistula with both stumps (1%)•• type E: fistula without concomitant esophageal

atresia (1%)

As pointed out above, only type A is reliably detectable inthe fetus by the non-visualization of the gastric bubble.

Etiology and pathogenesis. The etiology of the defect isunknown. It originates when, at 8 weeks of gestation,the primitive foregut does not divide into the ventraltracheobronchial part and the dorsal digestive part.

Ultrasound diagnosis. First, it should be underlinedonce more that more than 85% of cases of esophagealatresia are not detected in utero due to the existence of aconcurrent TE fistula: this fistula does not preventnormal stomach filling in most instances, and only in areduced number of cases is a constantly underfilled stom-ach found. In this regard, it is interesting to report that asonographic sign possibly associated with esophagealatresia in the presence of a small stomach has beendescribed in a few articles. This consists of a dilatation ofthe proximal esophageal tract, the so-called pouch sign.5

This sign is observed transiently also in the normal fetusafter swallowing; in fetuses with a small stomach andpolyhydramnios, the detection of a persistent pouch signwould indicate the likely presence of a TE fistula. Theoverall detection rate, considering all possible signs ofesophageal atresia, should be in the range of 24–42%.6,7

The only sign that, if present, is highly indicative ofesophageal atresia (but only in the 8–10% of cases thatare not associated with a TE fistula) is non-visualizationof the gastric bubble (Figure 7.9). As also shown in Figure7.7, a wide range of pathologic conditions may be associ-ated with this sign, and all of these should be ruled outprior to reaching a definite diagnosis of esophageal atre-sia. The fact that these anomalies include very severe or


CHARACTERIZATION OF MAJOR ANOMALIES

Incidence. Frequent: 1 /2500–1 /4000 live births.

Diagnosis. Non-visualization of the gastric bubble, relatively late-onset polyhydramnios. In some of the casesassociated with a TE fistula, a constantly small stomach. Inconstantly, an upper esophageal pouch (pouch sign).

Risk of chromosomal anomalies. High (20–44%): trisomies 21 and, to a lesser extent, 18.

Risk of non-chromosomal syndromes. Relatively high: VA(C)TER(L).

Outcome. Generally good, but depends mainly on the extent of the atretic tract.

ESOPHAGEAL ATRESIA – TRACHEO–ESOPHAGEAL (TE) FISTULA

Figure 7.9 Esophageal atresia. (a) At 23 weeks ofgestation, a suspicion of esophageal atreria (with-out TE fistula – see text) arises due to persistentnon-visualization of the gastric bubble in theabdomen. The amount of amniotic fluid is normal.(b) At 30 weeks of gestation, polyhydramnios hasdeveloped and the stomach is still not visualized:the diagnosis of esophageal atresia is confirmed.

a b


Definition. In esophageal atresia, the communicationbetween the proximal and the distal tract of the esophagusis absent, due to a lack of development of the intermediateesophageal portion, mainly because of an interruption ofthe blood supply during organogenesis. Esophageal atre-sia can occur as an isolated anomaly (10% of cases) or,much more frequently, be associated with a tracheo-esophageal (TE) fistula (90% of cases), i.e., an abnormalcommunication between the trachea and the distalesophageal stump. The frequent association with TE fis-tula is responsible for the extremely low intrauterinedetection rate: this is due to the fact that some amnioticfluid may actually reach the distal esophagus and eventu-ally fill the stomach, just by transiting through the fistula.If this is the case, then ultrasound diagnosis becomesvirtually impossible, being based on the detection of a con-stantly small gastric bubble. Anatomically, five types ofesophageal atresia are recognized, according to the Grossclassification,4 on the base of the anatomy and site of theTE fistula:

•• type A: no fistula (8% of cases)•• type B: fistula with proximal stump (1%)•• type C: fistula with distal stump (88%)•• type D: double fistula with both stumps (1%)•• type E: fistula without concomitant esophageal

atresia (1%)

As pointed out above, only type A is reliably detectable inthe fetus by the non-visualization of the gastric bubble.

Etiology and pathogenesis. The etiology of the defect isunknown. It originates when, at 8 weeks of gestation,the primitive foregut does not divide into the ventraltracheobronchial part and the dorsal digestive part.

Ultrasound diagnosis. First, it should be underlinedonce more that more than 85% of cases of esophagealatresia are not detected in utero due to the existence of aconcurrent TE fistula: this fistula does not preventnormal stomach filling in most instances, and only in areduced number of cases is a constantly underfilled stom-ach found. In this regard, it is interesting to report that asonographic sign possibly associated with esophagealatresia in the presence of a small stomach has beendescribed in a few articles. This consists of a dilatation ofthe proximal esophageal tract, the so-called pouch sign.5

This sign is observed transiently also in the normal fetusafter swallowing; in fetuses with a small stomach andpolyhydramnios, the detection of a persistent pouch signwould indicate the likely presence of a TE fistula. Theoverall detection rate, considering all possible signs ofesophageal atresia, should be in the range of 24–42%.6,7

The only sign that, if present, is highly indicative ofesophageal atresia (but only in the 8–10% of cases thatare not associated with a TE fistula) is non-visualizationof the gastric bubble (Figure 7.9). As also shown in Figure7.7, a wide range of pathologic conditions may be associ-ated with this sign, and all of these should be ruled outprior to reaching a definite diagnosis of esophageal atre-sia. The fact that these anomalies include very severe or


CHARACTERIZATION OF MAJOR ANOMALIES

Incidence. Frequent: 1 /2500–1 /4000 live births.

Diagnosis. Non-visualization of the gastric bubble, relatively late-onset polyhydramnios. In some of the casesassociated with a TE fistula, a constantly small stomach. Inconstantly, an upper esophageal pouch (pouch sign).

Risk of chromosomal anomalies. High (20–44%): trisomies 21 and, to a lesser extent, 18.

Risk of non-chromosomal syndromes. Relatively high: VA(C)TER(L).

Outcome. Generally good, but depends mainly on the extent of the atretic tract.

ESOPHAGEAL ATRESIA – TRACHEO–ESOPHAGEAL (TE) FISTULA

Figure 7.9 Esophageal atresia. (a) At 23 weeks ofgestation, a suspicion of esophageal atreria (with-out TE fistula – see text) arises due to persistentnon-visualization of the gastric bubble in theabdomen. The amount of amniotic fluid is normal.(b) At 30 weeks of gestation, polyhydramnios hasdeveloped and the stomach is still not visualized:the diagnosis of esophageal atresia is confirmed.

a b


with development of polyhydramnios and the stomach is still not visualized.

Absent/Small Stomach

persistent non-visualization of the gastric bubble in the abdomen.

Text

Suspected Diagnosis at 23 weeks

Confirmed Diagnosis at 30 weeks


The Coronal View, Using Three-dimensional Volume Contrast Imaging .

Sagittal view of the fetal neck, showing the course of the esophagus which is temporarily dilated by the swallowing of some amniotic fluid.

The Pouch Sign


Rendered three-dimensional ultrasound image of the fetus showing the pouch in the fetal mediastinum, and the trachea. The pouch extended to the level of the C7 vertebrae. Esophageal atresia diagnosed with three-dimensional ultrasonography Ultrasound

Obstet Gynecol 2005; 26: 307–308

MRI partially revealed the characteristicpouch sign.


Esophageal atresiaObstetric Management

★Assessed For Associated Anomalies.

★Genetic Amniocentesis.

★Delivery At Tertiary Care Center.

★Esophageal Abnormalities Alone Are Not An Indication For Altering The Route Of Delivery.

Outcome:

•The Extent Of The Atretic Tract.

•Associated Anomalies.Thursday, November 28, 13


✦Non-visualization Of The Gastric Bubble.✦Cystic Lesions (Double Bubble And Its DD).


✦Dilated Large Bowel.✦Echogenic Bowel”.



Persistent right Umbilical vein

Umbilical Vein Varices

Choledochal cysts

Hepatic cysts

Duodenal Atresia

Urachal Cysts

Mesenteric cysts

UreteroceleSplenic Cysts

Enteric Duplication

Cysts

Ovarian Cysts

Duplex kidney

Adrenal Hemorrhage

Dilatation of the renal pelvis

Multicystic Dysplastic Kidney

For final diagnosis both the location of the mass and its ultrasound appearance should be taken in consideration

Cystic Lesions


DUODENAL ATRESIA

Definition: The Tract Between The Proximal And Distal Portions Of The Duodenum Is Atretic.

22 wks


Incidence: 1/2500 - 1/10 000 Life Births. Atresia Accounts For Up To 75 Percent Of Intestinal Obstructions.


•Chromosomal Anomalies: Up To 40% Association With DS.

• Non Chromosomal Anomalies: 40–50% Of Cases. (other GI, Vertebral (33%), Cardiac Anomalies (30%). Intestinal Malrotation (40%), More Severe Anomalies Of The Biliary Tract And Of The Pancreas (annular Pancreas).


Incidence: 1/2500 - 1/10 000 Life Births. Atresia Accounts For Up To 75 Percent Of Intestinal Obstructions.

The Etiology: Is Unknown.

The Pathogenetic: Interruption Of Blood Supply During Organogenetic Period. Or Lack Of Duodenal Recanalization.


•Chromosomal Anomalies: Up To 40% Association With DS.

• Non Chromosomal Anomalies: 40–50% Of Cases. (other GI, Vertebral (33%), Cardiac Anomalies (30%). Intestinal Malrotation (40%), More Severe Anomalies Of The Biliary Tract And Of The Pancreas (annular Pancreas).


3 Types of DUODENAL ATRESIA

Type 1The muscular

wall is intact But

Membranous mucosal

atresia (69%)

Type 3 Complete separation of the two ends plus

biliary tract anomalies

Type 2Short fibrous

cord connects the two ends of the atretic duodenum

duodenumduodenum


★The classic double bubble With communication in between.

★ Associated polyhydramnios.

Definition. In duodenal atresia, the tract between theproximal and distal portions of the duodenum is atretic.In most cases (80%), the obstruction is due to completeatresia and is caudal to the ampulla of Vater. In theremaining 20% of cases, the obstruction can be due to adiaphragm or membrane located within the lumen of theduodenum, and can be complete or partial (stenosis).

Etiology and pathogenesis. The etiology of the defectis unknown. The pathogenetic mechanism involvesan interruption of blood supply during organogeneticperiod, as for most GI tract atresias. According toanother theory, the defect may be due to a lack of duode-nal recanalization – always during early embryogenesis.

Ultrasound diagnosis. This is based upon recognition ofthe classic double bubble, associated with polyhydram-nios, which often develops in the late 2nd, early 3rdtrimester. Usually, when the midtrimester anomaly scanis carried out (at 18–21 weeks of gestation in most coun-tries), polyhydramnios is absent and the double bubblehas not yet completely developed: the only finding con-sists of an evidently dilated stomach, with initial dilata-tion only of the duodenum (Figure 7.10a,b). Duringfollow-up scans, which should always be scheduled if thestomach presents the above-mentioned features (enlarge-ment and evidence of pylorus), the classic double bubblebecomes clearly visible (Figure 7.10c). Care should betaken in demonstrating a communication between thetwo anechoic bubbles, to obtain confirmation that thesecond bubble is actually the dilated proximal duode-num (Figure 7.10b): only by demonstrating this commu-nication can the rare occurrence of enteric duplicationcysts or other upper abdominal cysts (Figure 7.8) beruled out. Furthermore, it should be noted that, in theless common cases of duodenal stenosis, most of whichare not diagnosed prenatally, the double bubble maybecome visible only late in gestation or may even neveroccur, with a constantly dilated stomach with evidenceof the pylorum being the only sign of the partial obstruc-tion. Finally, it should be underlined that in theextremely rare cases in which duodenal atresia is associ-ated with esophageal atresia, the overdistension of thestomach and proximal duodenum is massive.

•• Differential diagnosis. This should include allother conditions featuring a cystic structure in themiddle or right upper abdomen (Figure 7.8): chole-dochal cysts, enteric duplication cysts, and hepaticcysts. The differential diagnosis is made by simplydemonstrating the communication between the right-sided anechoic structure and the stomach: if this com-munication exists, then the diagnosis can only beduodenal atresia.

•• Prognostic indicators. The association with otheranomalies, which is relatively frequent, represents themain poor prognostic sign.

•• Association with other malformations. Major anom-alies are associated with duodenal atresia in 40–50% ofcases, with a prevalence (in decreasing order) of otherGI, vertebral (about 33%), and cardiac anomalies


Figure 7.10 Duodenal atresia. (a) At 23 weeks of gestation, initial evi-dence of a double bubble is detected (arrow). (b) After a fewminutes, intestinal peristalsis demonstrates the communication betweenthe stomach (st) and the dilated proximal duodenum. (c) Later in gesta-tion, a clear double bubble (arrow) has developed, confirming the suspi-cion of duodenal atresia. (d) Three-dimensional ultrasound withinversion mode rendering: the site of the obstruction is clearly visible.

Incidence. Frequent 1 /2500–1 /10 000 live births.

Diagnosis. Double bubble, with communication between the two parts; late polyhydramnios.

Risk of chromosomal anomalies. High (20–50%): mainly trisomy 21.

Risk of non-chromosomal syndromes. Low.

Outcome. Mainly good.

DUODENAL ATRESIA

a

c d

b















DUODENAL ATRESIA

a

c d

b


Duodenal atresia. (a) At 23 weeks of gestation, initial evidence of a double bubble is detected (arrow). (b) After a few minutes, intestinal peristalsis demonstrates the communication between the stomach (st) and the dilated proximal duodenum.

Ultrasound Findings















DUODENAL ATRESIA

a

c d

b















DUODENAL ATRESIA

a

c d

b


Three-dimensional ultrasound with inversion mode rendering: the site of the obstruction is clearly visible.

Later in gestation, a clear double bubble (arrow) has developed, confirming the suspicion of duodenal atresia.

Ultrasound Findings


• In the absence of communication between stomach and Duodenum the DD of other upper abdominal cysts should be considered.

• Type 2 and 3 of duodenal stenosis are rarely diagnosed prenatally.

• May be suspected late in pregnancy because of a constantly dilated stomach with evidence of the pylorum in late gestation.

Ultrasound Findings


★Karyotyping.

★Search For Associated Malformations (including Fetal Echocardiography).

★Measures Against Risk Of Preterm Delivery Because Of The Severe Polyhydramnios.

★Delivery In A Tertiary Referral Center.

Duodenal Atresia Obstetric Management

✤Isolated cases have have overall survival of about 90%

✤Late- onset sequelae: e.g. megaduodenum, duodenogastro-esophageal reflux, and peptic ulcers.

Prognosis:





✦Dilated Large Bowel.✦Echogenic Bowel”.

✦Large Liver / Spleen.✦Abdominal Wall Defects.


✴Ileal & Jejunal Atresia.

✴Meconium Ileus.



Ultrasound Findings Suggestive Of GIT Malformations



Right Para-sagital

Left Para-sagital

★Rt. Lung. ★Diaphragm.★The Rt. Hepatic

Lobe.★Some Ileal

Loops.

★The Stomach & The Spleen

Coronal View

★Non-visualization Of The Gastric Bubble.

★Double Bubble.

★Dilated Bowel Loops.

★Echogenic Bowel.

★Cystic Lesions.



Diagnosis:

•Dilatation Of The Ileal Loops Proximal To The Obstruction.

•Polyhydramnios.

Associated Anomalies:Low Risks Of Both Chromosomal And Non-chromosomal Syndromes.

Pathogenesis: Intrauterine Vascular Accidents Leading To Ischemic Necrosis Of The Bowel And Resorption Of The Affected Segment.

Ileal & Jejunal ATRESIA


Type I 20%

Intraluminal Membrane With Intact

Bowel Wall & Mesentery

Type II 35%

Blind Ends Are Separated By A Fibrous

Cord

Type IIIa 35%

Blind Ends Are Separated

By A V-shaped

Mesenteric Defect

Type IIIb “Apple-peel”

typeextensive

mesenteric defect and a loss of the normal blood

supply to the distal bowel.

Type IV 5%

Multiple segments of bowel atresia

Types Of Jejunal And Ileal Atresia

Poor Prognosis


Ileal Atresias

•More Often Single.

•Higher Tendency To Perforation.

•Higher Birth Weight.

•Lesser Risk Of PTL.

Jejunal Atresias

• More Often Multiple.

• Tend To Dilate Rather Than To Perforate.

• Low Birth Weight.

• More Tendency To PTL.


Axial Midlevel Abdominal Scan At 24 Weeks Showing Doubtful Sign Of Atresia •Moderate Dilatation (>7mm) Of A Single Ileal/jejunal Loop.•Hyperechoic Bowel Walls.

Ultrasound Findings 24 Weeks Suspected Abnormal Dilatation


The obstruction becomes evident, with moderately severe dilatation of various loops.

The communication between the various dilated segments (the maximum transverse diameter of the loops was 23 mm).

Ultrasound Findings

Same case at third trimester At 36 Weeks


Differentiate Between Ileal Or Jujenal Atresia Is Difficult. The Only Points Are The Evidence Of Intestinal Perforation (ascites With Particulate Matter And/or Calcifications) For The Ileal Or Extreme Dilatation Without Perforation For The Jejunal.

Jejunal Atresia (37 Weeks Of Gestation) With Extremely Severe Dilatation Without Evidence Of Perforation (absence Of Meconium Peritonitis).


Axial View at 27 weeks gestation showing several dilated loops of fluid filled bowel. Postnatally

confirmed isolated ileal atresia.Thursday, November 28, 13

✴Hirschprung’s Disease (Aganglionic Megacolon)

✴Volvulus (Appears Over 3-4 Days).

✴Meconium Ileus .

Differential Diagnosis:


MECONIUM ILEUS

A Mechanical ileal obstruction due to the increased consistency of meconium.

It carries significant risk of perforation and consequent meconium peritonitis with a consequent severe adhesive peritonitis

Associated Anomalies: Cystic Fibrosis (Approximately 10% of infants with cystic fibrosis develop meconium ileus and 90% of infants presenting with meconium ileus)


Axial scan at 29 weeks

Ultrasound Findings

dilatation of ileal loops with

hyperechoic walls (arrow)

Macrocalcifications demonstrates the

perforation


Oblique View Of The Same Case Demonstrates The Presence Of A Secluded Sac Of Ascites Containing Meconium Sludge (arrow).

Ultrasound Findings


Ultrasound Diagnosis.

Meconium Peritonitis As Evident By Diffuse Intra-abdominal Calcifications

Ultrasound Findings


Axial image shows a large cystic mass containing echogenic fluid anterior to dilated bowel loops consistent with a meconium pseudocyst.

Prenatal ultrasound image of ileal atresia with meconium pseudocyst

Sagittal ultrasound at 28 weeks of gestation shows several dilated loops of bowel.


Obstetric Management


Prognosis, Survival, And Quality Of Life: Depends On The The Presence Of Meconium Peritonitis. The Association With Cystic Fibrosis And Its Severity.



Prognosis, Survival, And Quality Of Life: Depends On The The Presence Of Meconium Peritonitis. The Association With Cystic Fibrosis And Its Severity.

• Screening Parents For CF Carrier Status

• Consider Amniocentesis For Fetal DNA Testing For Cystic Fibrosis.

• Delivery In Tertiary Care Unit.





✦Dilated Small Bowel (Ileal & Jejunal Atresia).

✦Dilated Large Bowel.✦Echogenic Bowel.✦Large Liver / Spleen.✦Abdominal Wall Defects


Echogenic Bowel

Diagnosis Usually In Second Trimester.

It Can Be Diffuse Or Focal.

Diagnostic Criteria: Echogenicity Similar To Or Greater Than That Of Adjacent Bone.Provided US Gain Set To The Lowest Point At Which Bone Appears White.

Prevalence: 0.4 -1% In The Second Trimester. In Normal Fetuses, It Is Generally Not Associated With Adverse Sequelae.


Normal bowel

The echotexture of the fetal bowel is homogenous, and is considerably less echodense than fetal bone.At low gain settings.


A very echogenic portion of fetal bowel seen in the mid abdomen that is as echodense as fetal bone.

Echogenic fetal bowelNormal bowel

The echotexture of the fetal bowel is homogenous, and is considerably less echodense than fetal bone.At low gain settings.


★Intraamniotic Bleeding:

★Aneuploidy:

★Cystic Fibrosis:

★Fetal Growth Restriction:

★Infection:

★Gastrointestinal Obstruction:

★Normal Finding In 0.4-1% Of Fetuses In Second Trimester With No Adverse Consequences.

Echogenic BowelAetiology


Intraamniotic bleeding and gastric pseudomass in fetus at 21 weeks' gestational age, 2 weeks after transplacental

amniocentesis

Intraamniotic bleeding


Echogenic fetal bowel at 15 weeks' gestational age in 33-year-old woman with vaginal bleeding associated with subchorionic hemorrhage


Echogenic bowel, Down syndrome

In this transverse image at the level of the umbilical cord insertion, the bowel is diffusely echogenic. At very low gain settings, the bowel is as echogenic as bone. Amniocentesis revealed fetal Down syndrome.


Echogenic bowel, cystic fibrosis

In this longitudinal image, there is a very echogenic portion of fetal bowel seen in the mid abdomen that is as echodense as fetal bone. Both parents were known carriers of the ΔF508 cystic fibrosis mutation, and the newborn was found to be homozygous for this mutation.


Meconium ascites

In this 20 week fetus, fetal ascites is noted in the lower abdomen, adjacent to what appeared to be a markedly echogenic loop of bowel.

fetal ascites

echogenic loop of bowel


Two weeks later, the ascites has resolved. The echogenic cystic area is still visible. After birth, imaging studies identified a

meconium pseudocyst.

Meconium Pseudocyst

In this 20 week fetus, fetal ascites is noted in the lower abdomen,

adjacent to what appeared to be a markedly echogenic loop of bowel.


✓Search For Other Markers (Trisomy). ✓Determine Recent History Of Bleeding. ✓Parental Screening For Cystic Fibrosis Carrier. ✓Maternal Serologic Testing For CMV And Toxoplasmosis.

✓Offer Amniocentesis For:

➡Fetal Karyotype: If The Priori Risk For Trisomy Is High.

➡DNA Testing For CF: If Both Parents Are Carriers.

➡PCR Testing For Infection (CMV&Toxoplasmosis): If There Is Serologic Evidence Of Recent Maternal Infection.

✓Fetal Surveillance For Fetuses With Echogenic Bowel And FGR.

Echogenic Bowel






✦Dilated Large Bowel.✦Echogenic Bowel.



✤Hirschsprung disease:

✤Anorectal malformations:

✤Colonic atresia.

Often Missed Prenatally Because Fluid Is Resorbed In The Small Bowel And Colonic Loops.

The Small Bowel And Colon To Retain Normal Diameters Despite Distal Obstruction.

Colonic Obstruction


➡A Functional Obstruction Due To Aganglionosis Of A Segment Of Colon.

➡Prenatal Diagnosis Is Rare Unless It Is Due To Total Colonic Aganglionosis Which Result In Small Bowel Dilatation.

➡Associated Anomalies: Occur In 25% Of Cases, With A Strong Association With Trisomy 21.

Colonic Obstruction

✤Hirschsprung disease


✤Anorectal malformations:

•Types:➡“high” Supralevator Lesions: Above The Levator Sling, Typically Associated With

Fistulas.

➡“low” Infralevator Lesions: Below The Levator Sling, Not Associated With Fistulas.

•Associated Anomalies: 50 % Of Cases.➡Chromosomal Anomalies: High Risk Of Trisomy 21 And 18.

➡Non -chromosomal Syndromes: Include VACTERL Association (vertebral, Anal Atresia, Cardiac, Tracheoesophageal Fistula, Renal, Limb), Caudal Regression Syndrome, And Sirenomelia.

Colonic Obstruction


✤Clonic Atresia:

A Rare Condition Often Missed Prenataly. Occur Secondary To Vascular Accident Or Mecahnical Event “volvulus”.

•Associated Anomalies: Occure In 1/3 Of Cases Include:gastroschisis, Omphalocele, Hirschsprung Disease, Or Ocular And Skeletal Anomalies

Colonic Obstruction


Normal Filling Of The Rectal Pouch (arrow), Behind The Bladder

• Anorectal Atresia May Be Suspected In The Third Trimester Because Of Overdistension Of The Rectum , To A Lesser Extent, Of The Sigmoid Colon.

• The Presence Of Polyhydramnios Suggest Associated Anomalies.

Ultrasound Findings


Dilatation Of The Rectum, Shows Hyperechoic Content

Normal Filling Of The Rectal Pouch (arrow), Behind The Bladder

• Anorectal Atresia May Be Suspected In The Third Trimester Because Of Overdistension Of The Rectum , To A Lesser Extent, Of The Sigmoid Colon.

• The Presence Of Polyhydramnios Suggest Associated Anomalies.

Ultrasound Findings


➡Colonic Atresia.

➡Meconium Ileus.

➡Imperforate Anus.

➡Persistent Cloaca.

➡Meconium Plug Syndrome.

➡Fetal Diarrhea.

➡Megacystis Microcolon Hypoperistalsis Syndrome.

Differential Diagnosis Of Fetal Bowel Dilatation


Chromosomal anomalies: Risk high (trisomies 18 and 21).

Non-chromosomal syndromes: Risk is high. Include

✦VA(C)TER(L): look for → anorectal malformation + vertebral anomalies + cardiac defects + esophageal atresia (TE fistula) + renal agenesis + limb anomalies.

✦Caudal regression syndrome: look for → anorectal malformation + renal agenesis + sacral agenesis + lumbar vertebral anomalies + femoral hypoplasia + talipes.

✦Sirenomelia: look for → anorectal malformation + fusion of inferior limbs + renal agenesis + severe vertebral anomalies + genital anomalies.

Associated Anomalies


Vertebral defects

Anal Atresia

Cardiac defects

Tracheoesophageal fistula

Esophagyeal atresia

Renal anomalies

Limb defects

VACTERAL Complex


Ultrasound Findings Suggestive Of GIT Malformations



Right Para-sagital

Left Para-sagital

★Rt. Lung. ★Diaphragm.★The Rt.

Hepatic Lobe.★Some Ileal

Loops.

★The Stomach & The Spleen

Coronal View

★Non-visualization Of The Gastric Bubble.

★Double Bubble.

★Dilated Bowel Loops.

★Echogenic Bowel.

★Cystic Lesions.





✦Dilated Large Bowel.✦Echogenic Bowel.✦Large Liver / Spleen.✦Abdominal Wall Defects


Right parasagittal view, the degree of hepatomegaly is easily evaluated and the prominence of the abdomen in comparison with the normal thorax is evident.

✦The Liver


HEPATOMEGALY/SPLENOMEGALY

★ Incidence: Rare. Often due to severe fetal infections.

★ Diagnosis: Enlarged liver/spleen.

★ Risk of chromosomal anomalies: Low, except for the myeloproliferative disease typical of trisomy 21.

★ Risk of non-chromosomal syndromes: Rare but Hepatomegaly can be associated with the Beckwith–Wiedemann and Zellweger syndromes.

★ Outcome: Depends on the underlying cause.


✦Fetal Infections: “CMV”

✦Myeloproliferative Disease Associated With Down Syndrome.

✦Benign And Malignant Hepatic Tumors: Such As Hemangioma Or Hepatoblastoma.

✦Venous Congestion Secondary To I Cardiac And Extracardiac Conditions Possibly Causing Heart Failure.

✦Rare Syndromic Conditions, Namely The Beckwith–Wiedemann And Zellweger Syndromes.

Etiology And Pathogenesis:


At 19 weeks scanning patient with confirmed Hepatitis A shows evident hepatomegaly, with capsular macrocalcification and moderate ascites.

Ultrasound Findings


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, which was normal in this case (c) (SPL and arrowheads).

Left parasagittal view

Ultrasound Findings


Severe hepatomegaly due to CMV infection. The Liver is enlarged, hyperechoic, and rather inhomogeneous liver (arrows).

Ultrasound Findings


Coronal view, at 37 weeks of gestation, The spleen is severely enlarged spleen (Spl), the lower pole of which reaches the bladder (Bl) and a concurrent similarly severe hepatomegaly (Li).

Splenomegaly in two cases of severe fetal CMV infection

A similar case, at 36 weeks of gestation, showing severehepatosplenomegaly, ascites, and intra-abdominal calcifications.


•Test For Maternal Serologic Evidence Of Recent CMV Or Other Hepatotropic Infections.

•Ultrasound Assessment Searching For Additional Signs Of Fetal Infection (cerebral Calcification, Hydrocephalus,

•Ascites, And Cardiomegaly (myocarditis).

Prognosis, Survival, And Quality Of Life: Depends On Its Cause.






✦Dilated Large Bowel.✦Echogenic Bowel.



Thanks


Sonography of fetal GIT

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