O5‐01‐05: TAU IMAGING WITH 18 F‐MK6240 IN ALZHEIMER'S DISEASE AND OTHER DEMENTIAS

patients, two had F-MK6240 binding in medial temporal cortex much lower than expected (SUVRs of 1.71 and 1.99 vs. 3.44 5.48 for remaining amyloid-positive patients). One of these patients had high F-MK-6240 binding in neocortex, presented at an early age (53 years), was male, and had relatively large hippocampal volume compared to other amyloid-positive controls (1.0% vs 0.87 6 0.15% total intracranial volume, Fig 1B). This case may represent hippocampal-sparing AD, an atypical neuropathological subtype more frequently seen in males and in younger patients. The other amyloid-positive patient lacking medial temporal F-MK-6240 binding was older (78 years) and had low binding throughout the brain, despite small hippocampal volume (0.50% total intracranial volume, Fig 1C). This case may represent an amyloid pathophysiological process with a concomitant non-tau copathology (A+TN+). Out of 10 amyloid-negative patients, only one had evident F-MK-6240 binding in medial temporal cortex in range of amyloid-positive patients (SUVR 1⁄4 3.14, Fig 1D). This case may represent primary age related tauopathy (PART). Conclusions: 18