Magnetic resonance imaging for patients with permanent pacemakers: initial clinical experience.
BACKGROUND
Magnetic resonance imaging is a diagnostic tool of growing importance. Since its introduction, certain medical implants, e.g., pacemakers, were considered an absolute contraindication, mainly due to the presence of ferromagnetic components and the potential for electromagnetic interference. Patients with such implants were therefore prevented from entering MRI systems and not studied by this modality. These devices are now smaller and have improved electromechanical interference protection. Recently in vitro and in vivo data showed that these devices may be scanned safely by MRI.


OBJECTIVE
To report our initial experience with three patients with pacemakers who underwent cerebral MRI studies.


METHODS
The study included patients with clear clinical indications for MRI examination and who had implanted devices shown to be safe by in vitro and in vivo animal testing. In each patient the pacemaker was programmed to pacing-off. During the scan, continuous electrocardiographic telemetry, breathing rate, pulse oximetry and symptoms were monitored. Specific absorption rate was limited to 4.0 W/kg for all sequences. Device parameters were assessed before, immediately after MRI, and 1 week later.


RESULTS
None of the patients was pacemaker dependent. During the MRI study, no device movement was felt by the patients and no episodes of inappropriate inhibition or rapid activation of pacing were observed. At device interrogation there were no significant differences in device parameters pre-, post-, and 1 week after MRI. Image quality was unremarkable in all imaging sequences used and was not influenced by the presence of the pacemaker.


CONCLUSIONS
Given appropriate precautions, MRI can be safely performed in patients with a selected permanent pacemaker. This may have significant implications for current MRI contraindications.
Department of Radiology, Rambam Medical Center, Haifa, Israel.
Dorith
D
Goldsher
Shlomo
S
Amikam
Monther
M
Boulos
Mahmoud
M
Suleiman
Reuven
R
Shreiber
Ayelet
A
Eran
Yuval
Y
Goldshmid
Ramzi
R
Mazbar
Ariel
A
Roguin
D000368:Aged; D002985:Clinical Protocols; D000075202:Contraindications; D017147:Defibrillators, Implantable; D004574:Electromagnetic Fields / Q000009:adverse effects; D019544:Equipment Failure Analysis; D004869:Equipment Safety; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000009:adverse effects; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010138:Pacemaker, Artificial; D011446:Prospective Studies