Active groups are any of {HEAD ~ various pharmacologically or therapeutically active moieties}, including {TAIL ~ moieties} useful for magnetic resonance contrast enhancement 
including
Active groups are any of { HEAD ~ various pharmacologically or therapeutically active moieties } , including { TAIL ~ moieties } useful for magnetic resonance contrast enhancement
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH