Disclosure of amyloid imaging results to research participants: has the time come?

Amyloid imaging is becoming an increasingly popular tool in clinical research on Alzheimer's disease. In early studies, questions of whether to disclose amyloid imaging results were largely mooted by the immature state of the science. Lack of clarity as to what constituted a positive scan and what a positive scan meant from a prognostic or diagnostic perspective required investigators to advise research participants that, because their scans could not be meaningfully interpreted in a clinical sense, individual research scan results would not be disclosed. With a focus on the most widely used research tracer, Pittsburgh Compound B (PiB), we consider how advances in amyloid imaging are raising new questions about the appropriateness of withholding research results from study participants. We conclude that, although it remains advisable to withhold amyloid scan results from cognitively normal participants, it is no longer reasonable to uphold policies that unilaterally advise research participants with documented cognitive impairment that their PiB scans are uninterpretable. We outline circumstances that we believe compel investigators to provide research participants with the option of receiving their PiB scan results in a carefully managed fashion. Our findings can potentially be generalized to research involving all validated amyloid tracers.