Page 200 - Like me, or else... - Michelle Achterberg

Chapter 7
state towards the MR scan and MR protocol length. Previous research has described several child-specific scanner environment adaptations that have been used in (clinical) radiology departments (Galvan et al., 2012; Raschle et al., 2012; Fassbender et al., 2017b). One adaptation that has been shown to be particularly useful is the use of a mock scanner (Rosenberg et al., 1997; Hallowell et al., 2008; Durston et al., 2009), which replicates the MRI environment and can be used to familiarize young subjects with the procedure of an MRI scan. Children who underwent such an MRI simulation were less stressed (as indicated by lower heart rate) than children who were not trained with a simulator (Rosenberg et al., 1997). Moreover, studies showed a linear decrease in (self and parent reported) anxiety levels after MRI simulation (Rosenberg et al., 1997; Durston et al., 2009), indicating that an MRI simulation can make children feel more at ease with MRI research. This is important for the well-being of the participant, and a positive experience with the MRI scan can also increase retention of participants in longitudinal imaging studies, which is important for the validity of developmental MRI studies (Telzer et al., 2018). However, it is currently unknown whether a more positive emotional state towards the MRI scan is related to better outcomes in terms of scan quantity and quality. By using multi-informant estimations of emotional state, we directly tested the relation between scanner related distress and scan quantity and scan quality. We first examined how scanner related distress changed over time at three moments: before the MRI simulation, before the MRI scan, and after the MRI scan. We hypothesized that the emotional state would become more positive over time (Durston et al., 2009). Moreover, we hypothesized that there would be little influence of genetics on scanner related distress, as it is highly influenced by the environment (i.e., the MRI simulation). Next, we evaluated MRI scan quantity by investigating how scan quantity was related to emotional state, and to what extend scan quantity was influenced by genetics. Scan quantity was defined as the number of completed MRI runs within the protocol (ranging from 0-9). It should be noted that completing a run does not necessarily indicate that the MRI data is useable, and therefore scan quantity is essentially different from scan quality.
Similar to scan quantity, we investigated whether scan quality was related to emotional state, and to what extend scan quality was influenced by genetics. As an additional factor of interest, we examined scan quality across the duration of the MR session, as children tend to lose focus faster than adults, which may result in increased motion over time (Van Horn and Pelphrey, 2015; Fassbender et al., 2017b). Scan quality was examined in two ways: 1) the percentage of included MRI runs within the session (defined as the number of scans with sufficient quality relative to the number of runs completed), and 2) the amount of absolute and framewise head displacement in mm in fMRI runs. The first estimate of scan quality provides an overall, relatively simple measure of quality over the whole MRI session. The second measure provides a more sophisticated, quantitative measure of scan quality, but could only be calculated for functional MRI runs
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