IgG4-related Cardiovascular Disease from the Aorta to the Coronary Arteries: Multidetector CT and PET/CT.

Immunoglobulin G4 (IgG4)-related disease can affect the cardiovascular system, including the coronary arteries and pericardium and especially the walls of large and medium-sized vessels. The presence of coronary involvement is critical, as this condition can cause myocardial ischemia or sudden cardiac death. Although histopathologic examination remains the reference standard for detecting organ involvement and diagnosing IgG4-related disease, obtaining biopsy or surgical specimens from the vessel wall is still challenging. Because patients may be only mildly symptomatic, noninvasive imaging evaluation of IgG4-related cardiovascular disease (CVD) has an essential role in not only the diagnosis but also the management of this condition. Multidetector CT is a useful noninvasive examination for establishing the primary diagnosis and defining anatomic landmarks and their relationships. The spectrum of vessel involvement is vast, with varied manifestations. Radiologists should be familiar with inflammatory vasculitis, aneurysmal change, and pseudotumor formation in all vessels and the distribution of these conditions throughout the body. Electrocardiographically gated CT enables accurate, fast, and noninvasive characterization of coronary pathologic conditions and thus has an important advantage over catheter angiography. Combined PET/CT can depict inflammatory processes and help distinguish IgG4-related CVD from atherosclerosis. Familiarity with the PET/CT and CT findings of inflammatory processes involved in IgG4-related CVD is important for accurate diagnosis and evaluation of therapeutic response during follow-up. The multidetector CT and PET/CT characteristics of IgG4-related CVD, such as aortitis, periaortitis, arteritis, and periarteritis and including coronary artery involvement and pericarditis, are reviewed. In addition, the inflammatory process, quantification of active inflammation, and therapeutic response during follow-up associated with IgG4-related CVD are described. Online DICOM image stacks are available for this article. RSNA, 2018.