Imaging of post-infarct myocardial inflammation with 68Ga-DOTATATE PET/MRI

Abstract Background After myocardial infarction (MI), inflammation and its resolution modulate the extent of damage. 68Ga-DOTATATE is a PET tracer that binds to somatostatin receptor 2 (SST2), which up-regulated in pro-inflammatory macrophages [1]. Purpose We investigated PET/MRI for quantifying post-infarct inflammation. Methods In this prospective observational cohort study, participants with MI underwent at baseline (t0: <2 weeks post-MI) 3 months (t3M). Patients prior MI, heart failure, coronary revascularisation, or contraindication PET/MRI, were excluded. Blood samples taken time imaging high sensitivity CRP (hsCRP), troponin I (hsTnI), NTproBNP peripheral blood monocyte subset counts measured by mass cytometry. maximum Standardised Uptake Values (SUV) Tissue-to-Background Ratios (TBR) adjusted pool activity compared infarct defined late gadolinium enhancement (LGE) MRI remote myocardium t0 t3M. Results Thirty-two patients (mean age 59 [SD 9] years; 26 [81%] male 6 [19%] female), comprised 18 (56%) ST elevation 14 (44%) non-ST enrolled. Mean peak was 16,953ng/L (range 408 >25,000ng/L), 16 (52%) had left ventricular impairment (ejection fraction <50%). signal co-localised LGE focal oedema (arrows) on T2-weighted (Fig. 1; asterisk: culprit artery) excellent ability discriminate from regions SUV 2.41 vs. 1.58, p<0.0001; t0: TBR 5.08 3.35, Fig. 2a). At 100 (SD 13) days after (n=23 patients), residual uptake remained higher than (t3M: 1.88 1.27, t3M: 3.96 2.73, p<0.0001), but reduced (SUV −22%, p=0.002; 2b). Reduction consistent overall decreases hsCRP (2.16 8.76 mg/L), hsTnI (19 1365 ng/L) (372 959 pg/mL) t3M (n=23, all p<0.05). Focal resolved 17 (74%) Infarct-to-remote ratio correlated (r=0.35, (n=9 samples) vs (n=20 samples), there reduction % classical-to-non-classical monocytes 6.5 3.8] 14.4 11.2], p=0.005). Conclusions This first study serial MI. Here we show tracks resolving Ongoing work as part seeks confirm cellular origin infarct-related SST2 expression within inflamed tissue, test longer-term association ischaemic remodelling. Funding Acknowledgement Type funding sources: Foundation. Main source(s): Wellcome TrustBritish Heart Foundation