Event rates in subgroup analyses.

Values are arithmetic mean (standard deviation [SD]) or number (%) and 95% confidence intervals (CI). Percentages may not total 100% because of rounding. P values were obtained using the chi-squared and Fisher's exact test. See Figure 1 for the flow of patients. Patients who did not attend their MR imaging appointment were classified as having an event for the intention-to-treat analysis but not for the per-protocol analysis.*The body mass index (BMI) is the weight in kilograms divided by the square of the height in meters.†Including MR imaging which was prevented, aborted or performed with conscious sedation due to claustrophobia.‡For MR imaging of the cervical spine, the shoulder, and the head, patients were examined head-first because feet-first imaging, which alleviates claustrophobia by a factor of more than 10, was possible only for lumbar spine imaging in both groups [12].