Cardiac Fibroblast Activation in Patients Early After Acute Myocardial Infarction: Integration with MR Tissue Characterization and Subsequent Functional Outcome

The Journal of Nuclear Medicine

article

Johanna Diekmann¹  Tobias Koenig²  James T. Thackeray¹  Thorsten Derlin¹  Christoph Czerner¹  Jonas Neuser²  Tobias L. Ross¹  Andreas Schäfer²  Jochen Tillmanns²  Johann Bauersachs²  Frank M. Bengel¹ 

[1] Department of Nuclear Medicine, Hannover Medical School;Department of Cardiology and Angiology, Hannover Medical School

关键词: myocardial infarction;    fibroblast activation protein;    PET;    left ventricular remodeling;   

DOI  :  10.2967/jnumed.121.263555

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

After acute myocardial infarction (AMI), fibroblast activation protein (FAP) upregulation exceeds the infarct region. We sought further insights into the physiologic relevance by correlating FAP-targeted PET with tissue characteristics from cardiac MRI (CMR) and functional outcome. Methods: Thirty-five patients underwent CMR, perfusion SPECT, and 68Ga-FAP inhibitor (FAPI)-46 PET/CT within 11 d after AMI. Infarct size was determined from SPECT by comparison to a reference database. For PET, regional SUVs and isocontour volumes of interest determined the extent of cardiac FAP upregulation (FAP volume). CMR yielded functional parameters, area of injury (late gadolinium enhancement [LGE]) and T1/T2 mapping. Follow-up was available from echocardiography or CMR after 139.5 d (interquartile range, 80.5–188.25 d) (n = 14). Results: The area of FAP upregulation was significantly larger than the SPECT perfusion defect size (58% ± 15% vs. 23% ± 17%, P < 0.001) and infarct area by LGE (28% ± 11%, P < 0.001). FAP volume significantly correlated with CMR parameters at baseline (all P < 0.001): infarct area (r = 0.58), left ventricle (LV) mass (r = 0.69), end-systolic volume (r = 0.62), and end-diastolic volume (r = 0.57). Segmental analysis revealed FAP upregulation in 308 of 496 myocardial segments (62%). Significant LGE was found in only 56% of FAP-positive segments, elevated T1 in 74%, and elevated T2 in 68%. Fourteen percent (44/308) of FAP-positive segments exhibited neither prolonged T1 or T2 nor significant LGE. Of note, FAP volume correlated only weakly with simultaneously measured LV ejection fraction at baseline (r = −0.32, P = 0.07), whereas there was a significant inverse correlation with LV ejection fraction obtained at later follow-up (r = −0.58, P = 0.007). Conclusion: Early after AMI and reperfusion therapy, activation of fibroblasts markedly exceeds the hypoperfused infarct region and involves noninfarcted myocardium. The 68Ga-FAPI PET signal does not match regional myocardial tissue characteristics as defined by CMR but is predictive of the evolution of ventricular dysfunction. FAP-targeted imaging may provide a novel biomarker of LV remodeling that is complementary to existing techniques.

【 授权许可】

CC BY