External pneumatic compression device prevents fainting in standing weight-bearing MRI: a cohort study

To investigate if a peristaltic external pneumatic compression device attached to the legs, while scanning, can reduce a substantial risk of fainting in standing weight-bearing magnetic resonance imaging (MRI). This study comprised all patients with low back pain referred to standing MRI of the lumbar spine, using a 0.25-T open G-Scanner, from June 2011 to April 2012. The standing MRI protocol included a sagittal TSE T2w and an axial GRE T2w sequence giving a total scan time of 17 min. The first patients were scanned standing without a device (control group), and then from January to April 2012 the patients were scanned in the standing position using an external pneumatic compression device, attached to the legs (experimental group). One hundred and forty-nine patients (mean age 42.5, standard deviation 12.5, and range 20-77 years) were included and scanned standing. No significant difference in age (p = 0.51) or gender (p = 0.47) was observed between the control group (n = 86) and the experimental group (n = 63). Sixteen patients (19 %) fainted in the control group during the standing MRI scan, compared to one patient (2 %) in the experimental group where the pneumatic compression device was applied. The difference between groups was highly significant (p = 0.001; Fisher's exact test), with an OR = 0.071 (exact 95 % CI: 0.002 to 0.486) for the pneumatic compression device. A substantial risk of fainting during standing MRI was almost eliminated by using an external peristaltic pneumatic compression device.