CD68 and coronary atherosclerosis measurement: In a proof-of-principle study of 10 individuals undergoing carotid endarterectomy, 18F-fluorocholine (FCH) uptake, quantified as TBRmax, was significantly higher in symptomatic atheroma versus contralateral carotid arteries, and correlated with plaque CD68 content (rho = 0.648, p = 0.043), but did not correlate with the degree of carotid artery stenosis [102].