Detection of myocarditis using T1 and ECV mapping is not improved by early compared to late post‐contrast imaging. (30th June 2019)

• Record Type: Journal Article
• Authors: Lundin, Magnus; Sörensson, Peder; Vishnevskaya, Liya; Maret, Eva; Kellman, Peter; Sigfridsson, Andreas; Ugander, Martin
• Is Part Of: Clinical physiology and functional imaging. Volume 39:Number 6(2019:Nov.)
• Page Start: 384
• Page End: 392
• Publication Date: 2019-06-30
• Subjects: cardiac MRI -- cardiovascular magnetic resonance -- contrast agents -- contrast‐enhanced MRI -- ECV mapping -- gadolinium -- myocarditis -- T1 mapping; Physiology, Pathological -- Periodicals; Diagnostic imaging -- Periodicals; 612
• DOI: 10.1111/cpf.12588
• Languages: English
• ISSNs: 1475-0961

Abstract

Summary: Background: Cardiovascular magnetic resonance (CMR) of myocarditis may include early gadolinium enhancement (EGE) and global relative enhancement (GRE) by T 1 ‐weighted images acquired before and early after contrast administration. However, the importance of timing for post‐contrast imaging has not been evaluated using T 1 mapping. We aimed to improve the understanding of the contrast mechanisms by evaluating whether early or late post‐contrast T 1 mapping was better at detecting myocarditis. Methods: Controls and patients referred to evaluate myocarditis underwent 1·5T CMR. T 1 mapping was performed before, and 3 min (early) and 21 min (late) after intravenous contrast (0·2 mmol kg −1 ). Extracellular volume fraction (ECV) and the GRE and EGE equivalents by T 1 mapping were calculated. Focally affected myocardium in myocarditis was defined as increased native T 1 compared to remote myocardium. Results: The GRE equivalent by T 1 mapping was higher in myocarditis ( n = 19) compared to controls ( n = 19) both early ( P <0·001) and late ( P <0·001). While remote myocardium in myocarditis had higher enhancement relative to skeletal muscle compared to controls early ( P = 0·002) and late ( P <0·001), ECV of skeletal muscle was lower compared to controls both early ( P = 0·03) and late ( P = 0·004), and remote myocardial ECV did not differ from controls early ( P = 0·37) or late ( P = 0·52). The difference in ECV between affected and remote myocardium was higher late compared to early by 5·3 ± 0·7 versus 4·0 ± 0·6%‐points ( P = 0·002). Conclusion: Quantitative evaluation by T 1 mapping shows that early post‐contrast imaging does not improve the detection of myocarditis compared to late post‐contrast imaging. Focal myocardial abnormalities were more conspicuous late post‐contrast.