Fetal Ab Flashcards
The diaphragm separates the more echogenic lungs from the ____________ and the ____________.
Liver; stomach
The superior aspect of the abdominopelvic cavity is defined as a thin, dome shaped muscle which appears sonographically as a hypoechoic curved line. This is known as?
Diaphragm
You can see the diaphragm on a ____________ or ____________ view of the fetus.
Coronal; Sagittal
The _________ is a large organ occupying most of the upper abdomen.
Liver
The _________ lobe is larger than the _________ in the fetus.
Left; right
The anechoic, fluid-filled gallbladder is seen in the __________ right abdomen, _________ to the liver margin.
Anterior; inferior
What organ is difficult to see in the fetus?
Spleen
What organ is located in the left upper abdomen, posterior to the stomach and is echogenic and homogeneous?
Spleen
The development of anterior abdominal wall involves __________ __________ of the viscera into the base of the ___________ __________ during the first trimester.
Normal herniation
Umbilical cord
When does the development of abdominal wall occur?
8th - 12th to 14th week of gestation
The evaluation of the anterior abdominal wall should be performed after ______ weeks.
14
This is a small defect involving all three layers of the abdominal wall, allowing the intestines to protrude into the amniotic cavity. It usually occurs to the right of the umbilical cord insertion and has no covering or membranous sack.
Gastroschesis
What are the possible abdominal wall defects in the fetus?
- Gastroschesis
2. Omphalocele
In order to see gastroschesis, the fetus must be imaged with the fetal abdomen in __________ plane. You must look above and below at the level of the umbilical cord insertion.
Transverse
Gastroschesis is a sporadic defect, not associated with ____________ ____________ or other abnormalities.
chromosomal abnormalities
This results from failure of the intestines to return to the abdomen during the second stage of intestinal rotation which occurs before the 14th week of life.
Omphalocele
With gastroschesis, when and why do complications arise?
Complications arise postnatally with these babies because bowel gets stuck together due to exposure of amniotic fluid. Frequently, bowel obstructions occur in the pediatric and infant years.
An omphalocele could contain ___________ or most of the _________ contents, depending how severe
Bowel; abdominal
This defect is covered by a membrane which is a layer of amnion and peritoneum, and is present at the level of the umbilical cord insertion.
Omphalocele
There is high association between omphalocele and other congenital anomalies, most commonly _________ _________. There’s also associated chromosomal abnormalities, most frequently ________ _______ and _______.
Cardiac defects
Trisomy 13 and 18
If the ________ is contained with the omphalocele, there is less risk of associated chromosomal abnormalities.
Liver
- remember liver out is good
What are the ultrasound findings of an omphalocele?
- extra abdominal mass consisting of a combination of liver and/or bowel loops and sometimes other organs
- the mass is contiguous with the umbilical cord
- membranous sac covering herniated organs
This midline defect involves the lower abdominal wall as well as the anterior wall of urinary bladder. Generally, it is an isolated defect, characterized by exposure and protrusion of the urinary bladder but possibly associated with genital anomalies like cleft clitoris, epispadias, and wide separation of the pubic bones.
Urinary bladder Exstrophy
What are the ultrasound findings with urinary bladder exstrophy?
- the bladder will not be identified even over 30 minutes of scanning
- the amniotic fluid volume will be normal
- possible soft tissue protrusion may also be present from lower abdominal wall
- separation of pubic bones
- microphallus in male fetus
On transverse images, this structure is seen as an ovoid, fluid collection in the left upper quadrant of the fetal abdomen.
Stomach
__________ is not seen unless a stenosis present. Maybe seen in late stage pregnancies as the fetus swallowing.
Esophagus
What is gastric pseudo mass?
Swallowed cellular debris
Occasionally, you may see echoes within the stomach, particularly in late stage pregnancy which is called the _________ _________ ________.
Gastric pseudo mass
*this should not be mistaken for a tumor (see callen’s chapter on pitfalls.
What structure is difficult to isolate specific segments unless there’s fluid to provide contrast and is normally of mixed echotexture to cystic in appearance. You may see peristalsis by late second trimester.
Intestines
A mixture of bile and swallowed vernix, desquamated cells and fetal hair which fills the colon and may appear as echogenic. This is most obvious in the late third trimester. The colon is usually in the periphery of the abdomen and the small bowel is central.
Meconium
This abnormality can occur 1 in 2000-3000 live births. Defined as the discontinuity of the esophagus. 90% are accompanied by an distal trachea-esophageal fistula. There is 30-70% association with other congenital malformations including cardiac, GI, genitourinary, and musculoskeletal.
Esophageal Atresia
What are the ultrasound findings for esophageal atresia?
- small to absent fetal stomach
- failure to demonstrate the stomach even on serial ultrasounds
- associated polyhydramnios, because fetus is not swallowing the fluid
This abnormality is the most common perinatal intestinal obstruction. 65% of fetuses with this have either a chromosomal abnormality or an associated abnormality at birth, most commonly cardiac and vertebral abnormalities.
Duodenal atresia
30% of infants with duodenal atresia have ________.
trisomy 21 (downs syndrome)
What is the most important ultrasound finding of duodenal atresia?
- double bubble sign equals dilated stomach and dilated proximal duodenum.
What are the ultrasound findings of duodenal atresia?
- double bubble
- polyhydramnios, because there is limited swallowing of fluid
- the double bubble and polyhyramnios may not become apparent until after 24 weeks
An abnormality that is obstruction of the intestine with subsequent distentions of bowel loops. It may occur anywhere along the intestinal tract or at the level of the anus. The precise site is often unknown.
Intestinal atresia
What are the ultrasound findings of intestinal atresia?
- multiple fluid filled and distended bowel loops
- polyhyramnios
- possible perforation of the GI tract, indicated by abdominal calcification and ascites.
Sterile chemical peritonitis caused by small bowel perforation in utero. It can occur after fetal bowel obstruction caused by intestinal atresia, volvulus, or meconium ileus. Cystic fibrosis is considered to be the cause in 35 to 40% of cases because of thick, sticky meconium.
Meconium peritonitis
Meconium ileus and meconium peritonitis are associated with _________ _________.
cystic fibrosis
With meconium peritonitis what is seen on ultrasound?
- high specular echoes, corresponding to calcifications within the fetal abdomen. These may shadow.
- fetal ascities and polyhydramnios. may seen presence of a meconium pseudocyst.
What abnormality is described below:
- increased echogenicity of the fetal bowel can be identified on second trimester ultrasound
- it can be diffuse or focal, uniform or over a well defined area that does not shadow
- located primarily in the lower fetal abdomen and pelvis
Hyperechoeic bowel
What is the simplest criteria for diagnosis of hyperechoeic bowel?
more echogenic than adjacent fetal bone
*tends to look more echogenic when using higher frequencies and when using harmonics.
A __________ frequency should be used to evaluate hyperechoic bowel.
lower
What are the common causes for echogenic bowel?
- normal variant
- Trisomy 21
- Cytomegalovirus or CMV infection
Abdominal ascites in a fetus, is most commonly seen with __________ _________.
Hydrops Fetalis
