Risk perception in medical imaging: Understanding the effect of two risk presentation formats on knowledge (#226)
Medical imaging (MI), such as Computed Tomography (CT), is increasing. Patient knowledge of the risks associated with radiation exposure from MI is limited. The impact of increased knowledge of risks associated with CT scanning on intentions, anxiety and concern about MI is unknown.
To determine the efficacy of two information formats in increasing knowledge of the risks associated with CT scanning and to investigate the effect of increased knowledge on behavioural intentions, state anxiety and concern.
Design: Randomised controlled trial
Population: 143 adults from the general population
Intervention: Risk information format – participants were randomised to receive standard information format (SIF) presenting risk information numerically or a visual information format (VIF) with graphical risk information. The primary outcome measure was change in knowledge. Behavioural intentions, state anxiety and level of concern were also measured and paired-samples t-tests were conducted to determine the effect of information on these outcome measures. Change in (a) knowledge (b) intentions, (c) anxiety and (d) level of concern were regressed on risk format condition.
Overall, conceptual knowledge improved significantly from pre-intervention (M = 5.34, SD = 2.19) to post-intervention (M = 11.17, SD =1.84), p = .001. People receiving the SIF were, on average, .475 units higher in change in knowledge than those receiving VIF. However, this difference was not statistically significant (p =.267). Intentions, anxiety and level of concern did not change from pre- to post-test or as a function of information format (all p’s > .05)
Knowledge of the risks associated with CT scanning was low. Both information formats significantly improved participant knowledge of CT scanning risks. Behavioural intentions, anxiety and level of concern were unaffected. These results suggest full disclosure of potential MI risks increases knowledge about MI without increasing anxiety or concerns, or changing intentions, thereby supporting informed decision making.