Abstract: We included nine trials involving 1371 participants. Overall, results were mixed. Regarding five trials in clinical populations, three assessed smoking cessation behaviours, all featuring arterial scanning procedures to assess cardiovascular risk, and reported a statistically significant effect favouring the intervention, producing a pooled odds ratio (OR) of 2.81 (95% confidence interval (CI) 1.23 to 6.41, P = 0.01). One of these trials also measured physical activity and reported no statistically significant difference between the groups. A further trial measured skin examination behaviour following a skin photography procedure for assessing moles, and reported a statistically significant increase in favour of the intervention, with an OR of 4.86 (95% CI 1.95 to 12.10, P = 0.0007). The final clinical population trial measured a range of dietary intake and medication usage behaviours and featured an arterial scanning procedure assessing cardiovascular risk, and reported no statistically significant effects. Among the four trials in non-clinical populations, all featuring ultraviolet (UV) photography to highlight UV-related skin damage, a statistically significant result favouring the intervention was found in one trial for reducing tanning booth use, producing a mean difference (MD) of -1.10 (95% CI -1.90 to -0.30, P = .007) and one trial reported an outcome on which the control condition was favoured, with an MD of 0.45 (95% CI 0.04 to 0.86, P = 0.03) on intentional hours spent in the sun. In two further trials, no statistically significant behavioral effects were reported regarding time spent in the sun or sun protection behaviours. There was no evidence of significant adverse effects in the included trials, although this was not well reported. Due to the limited nature of the available evidence and the mixed results that were found, no strong statements can be made about the effectiveness of communicating medical imaging results to change health behaviour. Only three trials in clinical populations were similar enough in term of setting, intervention and outcome to allow meta-analysis. We suggest, however, that targeted interventions using medical imaging technologies may be effective in certain contexts, or as applied to certain behaviours, but that this should be considered on an intervention by intervention basis, and not assumed as a general principle.

Plain-language summary: We included nine trials involving 1371 participants in the review. In general, no strong evidence was found to support the effectiveness of this approach, but it was shown to be effective in some contexts. In smoking cessation interventions the effect of showing and explaining artery scanning images (to assess the risk of cardiovascular disease) was found to be more effective than not communicating images. In other outcomes, the effects were mixed. There was no evidence of significant harmful effects of this approach, although this was not well reported. A main limitation of the review is the small number of studies in this area and the great differences between them in terms of the precise nature of the interventions and the populations being studied. This makes drawing broad conclusions difficult.