Role of imaging in diagnosis of and differentiation between vasculitides

Imaging in vasculitis

Vasculitides may involve small, medium-sized or large arteries. In small-vessel vasculitides imaging studies of lungs, nasal sinuses, cerebrum, heart and other organs are important for determining disease extension and disease activity. Aneurysms are a hallmark of medium-sized artery vasculitides. In large-vessel vasculitis, imaging studies depict homogeneous, circumferential wall swelling and smoothly tapered luminal narrowing. Ultrasound and high-resolution magnetic resonance imaging (MRI) show characteristic wall abnormalities in temporal and occipital arteries whereas ultrasound, MRI, MR angiography, computed tomography (CT), CT angiography and positron emission tomography delineate characteristic features in extra-cranial arteries that are affected in large-vessel giant cell arteritis, Takayasu arteritis and idiopathic aortitis. Conventional angiography has still its place for therapeutic interventions. Imaging has led to a better understanding of the nature and distribution of vasculitides. It significantly facilitates diagnosis of patients with suspected vasculitis.

[Imaging techniques for the evaluation of systemic manifestations of vasculitis]

Vasculitides create a local inflammatory process in the vessel wall, which determines the different organic manifestations according to vessel size and location. Imaging techniques play a key role in the characterization and detection of large and medium size vessel vasculitides. Imaging is able to detect the vessel wall edema and to monitor the therapeutic response. In small vessel vasculitis, imaging can indirectly analyse the organic and/or systemic manifestations, because at present, none of the imaging techniques has the necessary spatial resolution to directly visualize small vessels.

Prognosis of large-vessel giant cell arteritis

OBJECTIVE

The prognosis of large-vessel GCA (LV-GCA) has not yet been investigated. How does it compare to GCA without arm vasculitis (GCA controls)?

METHODS

Charts of 53 LV-GCA patients and 53 GCA controls were reviewed following a predetermined protocol. Telephone interviews of patients or their primary care physicians were conducted. Forty LV-GCA patients underwent follow-up duplex ultrasound examinations of proximal arm arteries.

RESULTS

The mean observation time was 50 (s.d. +/- 31) months. None of the LV-GCA patients developed ischaemic arm complications. In 30%, proximal arm artery wall swelling disappeared completely. It decreased in 53%. In 8% it remained unchanged, in 5% it increased and in 5% arteries occluded with collateral flow. After the start of treatment, anterior ischaemic optic neuropathy developed neither in LV-GCA patients nor in GCA controls, amaurosis fugax occurred in 4 and 6%, arterial hypertension in 53 and 66%, strokes in 9 and 9%, myocardial infarction in 2 and 2%, diabetes mellitus in 30 and 25%, osteoporosis in 38 and 23%, and osteoporotic fractures in 15 and 4%, respectively. Mean corticosteroid dose was 3.7 mg/day. Mean duration of therapy was 42 months. All differences were insignificant. Four LV-GCA patients developed vasculitic popliteal artery stenoses.

CONCLUSIONS

The prognosis of LV-GCA is benign with regard to ischaemic complications. Proximal artery wall swelling decreases in most cases. Its course is similar to GCA without proximal arm arteritis.