Radiology Key

KEY FACTS Imaging • Exclusively in male fetuses • Bladder often grossly dilated, filling entire abdomen and increasing abdominal circumference • Distended bladder “funnels” into urethra ○ Keyhole sign from…

KEY FACTS Terminology • Reactive proliferation of placental tissue, not true neoplasm Imaging • Most common on fetal side of placenta, near cord insertion • Well-defined, hypoechoic mass • Flow…

KEY FACTS Imaging • Abdominal cyst in female fetus typically located in lower lateral abdomen or pelvis ○ Large cysts may extend into upper abdomen • Well circumscribed, generally anechoic,…

KEY FACTS Imaging • Obstruction at ureteropelvic junction (UPJ) leads to renal pelvis and calyceal distention • Renal pelvis dilated, elongated, and bullet-shaped ○ Can extend into pelvis and touch…

KEY FACTS Terminology • Urinary tract dilation (UTD) risk stratification system ○ A is for antenatal in UTD classification system – A1 = low risk for postnatal uropathy – A2-3…

KEY FACTS Imaging • > 90% of fetal cases arise in adrenal gland • May be solid, cystic, or mixed ○ Cystic appearance may represent involuting tumor and is excellent…

KEY FACTS Terminology • Most common nonlethal skeletal dysplasia Imaging • Long bones ○ Short limbs with normal ossification, no fractures ○ Rhizomelia: Proximal long bones (femur, humerus) more affected…

KEY FACTS Imaging • Inability to demonstrate normal anal dimple or target sign • Normal appearance ○ Axial: Hyperechoic mucosa within hypoechoic muscular ring ○ Coronal: Hyperechoic mucosal stripe between…

KEY FACTS Terminology • Definition: Genitourinary tract obstruction (at any level) causing renal parenchymal destruction Imaging • Progression: Urinary tract dilation (UTD) → ↑ renal echogenicity → small peripheral cortical…

KEY FACTS Terminology • Failure of kidneys to form Imaging • No kidneys in renal fossa or anywhere else in fetus • Adrenal glands are present and large, can mimic…