When are angiographic studies performed for the diagnosis of Polyarteritis nodosa?
When clinically involved tissue is not available for biopsy (e.g., a patient who presents with constitutional symptoms and digital ischemia).
Angiographic evaluation for PAN usually requires study of the abdominal viscera. The best plan is to study clinically involved organs: the kidney, liver, spleen, stomach, and small/large bowel. In rare cases, hand or foot arteriography is necessary. The sensitivity/specificity of visceral angiography is 90%. Although magnetic resonance angiography (MRA) and computed tomography angiography (CTA) are less sensitive in demonstrating microaneurysms, they are less invasive and may show organ infarcts (wedge-shaped areas in kidney; splenic infarcts). Fluorodeoxyglucose-positron emission tomography (PET) is not routinely used in the evaluation of medium-vessel vasculitis. In patients with muscle involvement, a “leopard skin appearance” can be seen; however PET is not indicated in patients with a suspicion of small- or medium-vessel vasculitis.
