iMAP™ imaging of tumorous lesions surrounding the coronary arteries in a patient with an elevated serum level of immunoglobulin G4

A 76-year-old woman with multiple coronary risk factors was admitted to our hospital because of episodes of new-onset chest pain that had begun 3 days previously. She underwent percutaneous coronary intervention (PCI) for severe stenoses in the two high lateral (HL) branches. Intravascular ultrasound (IVUS) revealed massive stenotic lesions in the HL branches and tumorous nonstenotic lesions in the left anterior descending coronary artery (LAD) and the left circumflex coronary artery (LCx). iMAP™, optical coherence tomography (OCT), and coronary computed tomography angiography (CCTA) were performed. iMAP depicted fibrosis in the vessel (green areas) and nonfibrotic tissue change suggestive of inflammation outside the vessel (yellow/red areas). OCT revealed high-intensity homogenous intimal hyperplasia with superficial calcification, and CCTA showed massive periarterial soft lesions in the HL, LAD, and LCx. The serum IgG4 level was high at 252–427 mg/dL (8 measurements) (reference range, 4.8–105.0 mg/dL). We suspected IgG4-related coronary periarteritis on the basis of the comprehensive diagnostic criteria as a possible diagnosis. The clinical course was good after initial and subsequent PCIs for both the HL stenoses and the progressing LCx stenosis, and there was no recurrence of angina pectoris thereafter. Steroids were not administered because the massive lesions did not enlarge during the 16 months of follow-up. iMAP was able to evaluate the tissue characteristics of tumorous lesions in the stenosed HL branches and the nonstenotic LAD and LCx in a patient with an elevated level of IgG4.