Claustrophobia during magnetic resonance imaging: Cohort study in over 55,000 patients

PURPOSE: To evaluate whether MR scanners with acoustic noise reduction and a short magnetic bore reduce the rate of claustrophobic reactions. MATERIALS AND METHODS: We performed a cohort study in an outpatient setting, enrolling a total of 55,734 consecutive patients referred for MRI of any part of the body based on a clinical indication. Imaging was performed using a conventional MR scanner (42,998 patients) and a recently developed MR scanner (12,736 patients) with 97% acoustic noise reduction and a short bore. Multiple logistic regression analysis was used to adjust for the nonrandomized design. RESULTS: In addition to those undergoing head-first examinations, female and middle-aged patients were significantly more likely to develop claustrophobia in the logistic regression analysis (P < 0.001). The rate of claustrophobic reactions was significantly lower with the recent MR scanner (0.7%; 95% confidence interval CI: 0.6-0.9%) than with the conventional scanner (2.1%; 95% CI, 2.0-2.3%; P < 0.001) with an adjusted odds ratio (OR) of 3.1 (95% CI, 2.5-3.9) and a number needed to treat of 72 (95% CI, 63-85). CONCLUSION: The incidence of claustrophobia may be reduced by a factor of 3 when recently-developed MR scanners are used.