IgG4-related cardiovascular disease. The emerging role of cardiovascular imaging.

Immunoglobulin 4-related disease (IgG4-related disease) is a systemic inflammatory disease that presents with increases of serum IgG4. It may affect various systems, including the cardiovascular (CV) system. Assessment of serum IgG4 levels and involved organ biopsy are necessary for diagnosis. IgG4-related disease is characterized by fibrosclerosis, lymphocytic infiltration and presence of IgG4-positive plasma cells. The disease usually responds to treatment with corticosteroids and/or immunosuppressive medication. CV involvement may manifest as cardiac pseudotumors, inflammatory periaortitis, coronary arteritis and/or pericarditis. IgG4-related cardiovascular disorders can severely affect patient prognosis. Various imaging techniques, including echocardiography, Computed Tomography (CT), 18FDG-PET, Cardiovascular Magnetic Resonance (CMR) and cardiac catheterisation, have been successfully used for early disease detection and follow-up. Echocardiography and vascular ultrasound are the most commonly used non-invasive, non-radiating imaging techniques for the evaluation of IgG4-related CV disease. Periaortitis/periarteritis can be also assessed by CT, showing a soft tissue thickening around arteries. Coronary artery aneurysms can be easily diagnosed by coronary CT. In case of active periarterial or coronary artery inflammation, 18FDG-PET will show FDG uptake at the area of the lesion. CMR, due to its capability to perform function and tissue characterisation, can offer an integrated imaging of aorta, coronary arteries and the heart, assessment of disease acuity, extent of fibrosis and guide further treatment. However, multimodality imaging may be necessary for assessment of disease activity and fibrosis extent in those cases with multifocal CV involvement.