Imaging description

A 12-year-old girl presented with acute abdominal pain. She had undergone chemo and radiation therapy seven years previously for metastatic neuroblastoma. The patient had experienced other, less severe episodes of abdominal pain over the past several months. On clinical examination she had diffuse abdominal pain, hypertension, and non-palpable femoral pulses. A CT scan demonstrated severe narrowing of the infrarenal abdominal aorta as well as occlusions of the celiac trunk, superior mesenteric artery (SMA), left renal artery, and focal narrowing of the proximal right renal artery (Fig. 43.1). The patient underwent a right renal artery angioplasty and right aortorenal bypass surgery.

Importance

Middle aortic syndrome (MAS) is a clinicopathologic term referring to significant, segmental tubular narrowing of the suprarenal, inter-renal, or infrarenal abdominal aorta, frequently associated with concomitant stenoses in the renal and visceral arteries. Ultrasound with Doppler and flow velocity investigations can directly detect the stenosis itself and demonstrate increased flow velocity and mono- or biphasic waveforms of arteries distal to the stenosis (as opposed to the normal triphasic waveforms). CT or MR angiographies can confirm the diagnosis. It is important to consider the possibility of MAS in specific patient populations and in the setting of classical clinical symptoms, described in more detail below. MAS can lead to a series of severe complications, including cerebral hemorrhage, cardiac infarctions, renal insufficiency, and mesenteric ischemia/infarction.