Direct Extension of IgG4-Related Periarteritis of the Coronary Artery to the Adjacent Myocardium Demonstrated Using Dual-Energy Cardiac Computed Tomography

A 69-year-old man with a history of sialadenitis and sinusitis was admitted with acute decompensated heart failure. Dual-energy coronary CT angiography (DE-CCTA) revealed no significant stenosis but huge coronary aneurysms in the proximal left anterior descending coronary artery and diffuse ectasia in the right coronary artery (RCA) (Supplementary Figure 1), similar to findings on invasive coronary angiography, and newly disclosed diffuse calcification in the RCA and severe wall thickening of the atrioventricular nodal artery (AVNA) adjacent to the inferior wall of the left ventricular (LV) at the base level (Figure A–D). Two-chamber views of delayed-phase dual-energy cardiac CT (DE-CCT) showed epicardial late iodine enhancement (LIE), adjacent to a soft tissue mass with LIE around the AVNA, in LV inferior wall at the base (Figure E–G). Cardiac magnetic resonance (CMR) similarly revealed epicardial late gadolinium enhancement (LGE) in the region of the AVNA (Supplementary Figure 2), which led to a diagnosis of IgG4-related coronary periarteritis extending to the adjacent myocardium, because the serum IgG4 levels were markedly elevated. There was spatial matching of LIE on DE-CCT and LGE on CMR.

Figure.

Dual-energy coronary CT angiography at 70 keV shows diffuse ectasia and calcification in the right coronary artery (RCA) and wall thickening of the atrioventricular nodal artery (AVNA) adjacent to the inferior wall of the LV at the base level (arrows) (A–D). Delayed-phase dual-energy cardiac CT shows epicardial late iodine enhancement (LIE) in the LV inferior wall at the base level (arrows) and adjacent to the soft tissue mass around the AVNA (arrowhead) at 50 keV (E); there is a significant increase in iodine density in the epicardial LIE area (2.6 mg/mL) within the blue region of interest (ROI) compared with a remote area in the anterior wall (0.9 mg/mL) within the yellow ROI on iodine density imaging (F); there is also a greater contrast between the LIE (blue curve) and the remote area (yellow curve) at 50 keV than at 70 keV, equivalent to conventional single-energy CT (G).

IgG4-related coronary periarteritis primarily involves the adventitia and its direct extension to the adjacent myocardium has not been reported. We found DE-CCT to be a comprehensive imaging modality for evaluating both coronary artery morphology and myocardial fibrosis in this patient with IgG4-related disease.

Disclosures

K.S. is a member of Circulation Journal’s Editorial Team.

Supplementary Files

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https://doi.org/10.1253/circj.CJ-23-0849