Interethnic variation in the prevalence of claustrophobia during MRI at Singapore General Hospital: does a wider bore MR scanner help?

Abstract

Background and objectives: It is estimated that 60 million magnetic resonance imaging (MRI) scans are performed annually around the world. Of these, 25% of patients experienced moderate to severe claustrophobia during the procedure. The aim of this study was to determine the prevalence and interethnic variations of patients requiring sedation due to claustrophobia. Another aim was to determine if a wider bore MR scanner was helpful in reducing the incidence of claustrophobia. Methodology: This was an institutional review board-approved study. We retrieved records for 11,813 adult outpatients from the hospital radiological system from 1 January 2012 to 31 December 2012. The data collected included patients’ gender, age, ethnicity, body region scanned, body orientation with respect to the scanner, the types of scanners used, and the need for sedation. Statistical analysis was performed using R 3.0.1. Results: The prevalence of claustrophobic patients requiring sedation was 0.45%, i.e. 53. Of these, 55% were females and 45% males. Among these, 64% were Chinese, 15% Malays, 15% Indians, and 6% were other races. 74% experienced claustrophobia at the 60 cm-wide bore scanners and 26% at 70 cm-wider bore scanners. Referring to Chinese, multivariable regression showed Malays and the Indians were six times and other ethnic groups were 12 times more likely to develop claustrophobia. The incidence of claustrophobia could be reduced by a factor of 2.95 with wider bore scanners. Conclusions: The MR environment is still disturbing to some patients. Feet-in positioning does not significantly minimize claustrophobia. Gender and age had no bearing on claustrophobia. Wider bore MR scanners with a bore size of 70 cm are an obvious choice toward more patient-friendly MR scanners.