Myocardial uptake of ⁶⁸Ga-DOTATATE: correlation with cardiac disease and risk factors

Background: Myocardial uptake on ⁶⁸Ga-DOTATATE PET/CT is often observed and its clinical relevance is poorly understood. Purpose: To detect any correlation between myocardial uptake of ⁶⁸Ga-DOTATATE and presence of cardiac disease or risk factors. Material and Methods: In this institutional review board-approved retrospective study, we reviewed ⁶⁸Ga-DOTATATE PET/CT scans in our institution between 1 May 2018 and 30 September 2018. A semi-quantitative score (MUS) for myocardial uptake of ⁶⁸Ga-DOTATATE was developed by measuring mean standardized uptake value (SUV) in five myocardial regions, corrected by blood pool activity, and MUS was validated between two readers. We investigated the relationship between MUS and presence of cardiac disease or risk factors, including Framingham score and coronary calcification. Results: A total of 145 scans were included (79 women; mean age = 56.9 ± 13.7 years). Inter-reader agreement was excellent with intraclass correlation coefficient (r) = 0.964 (95% confidence interval [CI] = 0.903–0.987; P < 0.001). There was a weak but significant positive correlation between MUS and presence of coronary calcifications (Spearman rho = 0.20; P = 0.016). MUS was higher in patients with heart disease or risk factors (n = 83, mean MUS 2.03, 95% CI = 1.85–2.21) compared to those without (n = 23, mean MUS 1.40, 95% CI = 1.17–1.62; P < 0.001), although the cardiac disease group was older with a higher percentage of men (62.0 years, 57.8% men compared to 47.6 years, 13.0% men; P value <0.0001 for both comparisons). Conclusion: For patients undergoing ⁶⁸Ga-DOTATATE PET/CT scan, an elevated MUS might indicate an underlying heart disease.