Cardiac pacemakers, ICDs, and loop recorder: evaluation of translational attraction using conventional ("long-bore") and "short-bore" 1.5- and 3.0-Tesla MR systems

Abstract

Purpose: To evaluate magnet-related translational attraction for cardiac pacemakers, ICDs, and an insertable loop recorder in association with exposure to "long-bore" and "short-bore" 1.5- and 3.0-Tesla MR systems.

Materials and methods: Fourteen cardiac pacemakers, four ICDs, and one insertable loop recorder were evaluated for translational attraction using deflection angle tests performed at the points of the highest spatial gradients for long-bore and short-bore 1.5- and 3.0-Tesla MR systems according to ASTM guidelines.

Results: Deflection angles ranged from 9-90 degrees for the long-bore and from 11-90 degrees for the short-bore 1.5-T MR system. Deflection angles ranged from 23-90 degrees for the long-bore and from 34-90 degrees for the short-bore 3.0-T MR system. Three of the cardiovascular implants exhibited deflection angles > or = 45 degrees (i.e., indicating that they are potentially unsafe for patients) on the long-bore and short-bore 1.5-T MR systems. Eight implants exhibited deflection angles > or = 45 degrees on the long-bore 3.0-T MR system, while 14 exhibited deflection angles > or = 45 degrees on the short-bore 3.0-T MR system. In general, deflection angles for these cardiovascular implants were significantly (p < 0.01) higher on 1.5- and 3.0-Tesla short-bore compared to the long-bore MR systems.

Conclusions: Several of the cardiovascular implants that underwent evaluation may be problematic for patients undergoing MR procedures using 1.5- and 3.0-T MR systems because of risks associated with magnet-related movements. Obviously, additional MR safety issues must also be considered for these implants.