<unk> s are commonly diagnosed incidentally on abdominal imaging. The diagnosis can be made with many different imaging modalities such as ultrasound, intravenous pyelogram, CT, and MRI. Common features that can be found on imaging include: * Midline symmetrical fusion (present in 90% of cases) or lateral asymmetric fusion (present in 10% of cases) of the lower poles * Position of fused kidneys are lower than normal with incomplete medial rotation * Renal pelvis and ureters are positioned more anteriorly and ventrally cross the isthmus * Isthmus that may be positioned below the inferior mesenteric artery * Variant arterial supply that can originate from the abdominal aorta or common illiac arteries * Lower poles of kidney that extend ventromedially and may be poorly defined
Horseshoe kidney
Page kidney
Multicystic dysplastic kidney
Ectopic kidney
Crossed renal ectopia
Supernumerary kidney
Medullary sponge kidney
Renal segmental hypoplasia