Indium-111 labelled leucocyte uptake in aortitis

Inflammatory conditions of the aorta may present with non-specific clinical features, including unexplained fever. Indium-111 labelled leucocyte imaging may be performed in such patients to look for the presence of occult sepsis or to assess the activity of a known vasculitis. Of approximately 1100 patients to undergo leucocyte scintigraphy for these indications over a 5 year period, three had focal leucocyte uptake in the aorta. The final diagnoses were: (1) periaortitis in Wegener's granulomatosis; (2) aortic dissection in giant cell arteritis; and (3) streptococcal aortitis with impending rupture. In all three cases the uptake was initially not thought to be in the aorta, but in bowel, a paravertebral abscess and in the lumbar spine respectively. Further imaging with CT and MRI led to the correct diagnoses. As the aorta is a rare site of focal leucocyte uptake, errors in image interpretation are likely. The rapid diagnosis of inflammatory conditions of the aorta is essential, however, as they may be life-threatening if unrecognized; therefore awareness of the aorta as a potential site of uptake is important. Urgent referral for further imaging is imperative in these cases as a false or delayed diagnosis may lead to avoidable morbidity and mortality.