Fetal Abdomen and Genitourinary system

stomach

• seen in the left upper quadrant

• should be seen by 16w

• amniotic fluid filled structure

• used as a marker for taking an AC measurement

• if no fluid seen (stomach is empty) check later in the exam

small bowel

sonographic appearance varies with menstrual age

• mid gut herniation

• early pregnancy: hypoechoic

• late pregnancy: more echogenic

Hyperechoic bowel is NOT normal. echogenicity should be less than bone

may see peristalsis of the small bowel in?

3rd trimester

Large bowel

• seen after 22 weeks

• hypoechoic tubular structure

• haustral folds appear as thin linear echoes within the lumen

Liver

occupies the upper right abdomen

left lobe is larger in utero

Sonographic appearance of liver

homogenous, moderate echogenicity

Gallbladder

• seen after 20 weeks

• elongated fluid-filled structure

• more oval than the intrahepatic umbilical

Spleen

• sits in the left upper quadrant

• increases in size during gestation

• homogenous, similar to kidney, less echogenic than the liver

• best imaged in trans, left of stomach

abdominal cord insertion (ACI)

• umbilical cord seen entering the fetal abdomen just above the level of the bladder

• courses to the liver within the falciform ligament

• ensure smooth abdominal cord insertion

• rule our gastroschisis and omphalocele

kidneys develop from that organs?

excretory organs in the embryo

• pronephros

• mesonephros

• metanephros

form in the pelvis and ascend into the abdomen

kidneys

how should kidneys be evaluated?

• presence, number, position

• size

• collecting system dilation

• appearance (texture and echo)

describe kidney sono

• homogenous cortex

• hypoechoic pyramids and anechoic collecting system

how are kidneys imaged?

TRV

• on either side of the spine

• measure AP diameter of renal pelvis

LONG
- long axis of the kidney

renal pelvis size criteria

< 27w >4mm abnormal

27-40w: >7mm abnormal

adrenals

best seen in trv

hypoechoic cortex, echogenic medulla

bladder

• empties and fills at least one every 30min

• empty bladder is an indication of an abnormality

• anechoic fluid filled

Genitalia

develop between 9-12 weeks

fetal testes produce androgens that cause masculinization of the external genetalia

turtle sign

for male

three-line sign/hamburger sign

for girl