Accumulation of technetium-99m tetrofosmin on myocardial perfusion scintigraphy in a patient with immunoglobulin-G4 related coronary periarteritis

A 50-year-old man presented with an abnormal chest radiograph during an annual medical examination. Non-contrast-enhanced chest computed tomography (CT) revealed multiple mediastinal lymphadenopathies and pericardial masses. Contrast-enhanced coronary CT angiography showed multiple pericoronary masses with strong contrast enhancement surrounding the coronary arteries and abnormal coronary arterial dilatation (Fig. 1A and B). Invasive coronary angiography detected multiple coronary aneurysms in the right coronary artery and left circumflex artery (LCX), and a giant pseudoaneurysm at the LCX (Fig. 1C and F, and Supplementary Video S1 and S2). The image fusion of technetium-99m tetrofosmin (Tc-99m-TF) myocardial perfusion single-photon emission computed tomography (SPECT) and CT revealed tracer accumulation in the pericoronary-arterial masses (Fig. 1D and E). The patient’s immunoglobulin-G4 (IgG4) level was elevated (4380 mg/dL), and was diagnosed with IgG4-related coronary periarteritis (IgG4-rCP). Oral steroid therapy (40 mg/day) was initiated, and the dose was gradually decreased to 10 mg/day. A follow-up CT scan showed that the mass had shrunk, and the serum IgG4 level had decreased (320 mg/dl).