The diagnosis of polyarteritis nodosa (PAN) is often delayed because patients present with diverse clinical symptoms, but with less disease-specific signs. However, early diagnosis and treatment of PAN is necessary to prevent serious organ damage. Herein, we present a boy in whom the diagnosis of classical PAN was established rapidly with ultrasound and computed tomography (CT) angiography. Moreover, complete disappearance of the aneurysms after one month of therapy was documented. This case is presented in order to underline the role of new imaging techniques in the diagnosis and follow-up of patients with PAN.