Gg. Hartnell et al., SAFETY OF MR-IMAGING IN PATIENTS WHO HAVE RETAINED METALLIC MATERIALSAFTER CARDIAC-SURGERY, American journal of roentgenology, 168(5), 1997, pp. 1157-1159
OBJECTIVE. Epicardial pacing wires retained in patients who undergo ca
rdiac surgery are thought to be a relative contraindication to MR imag
ing. However, to our knowledge no published evidence supports this bel
ief. Because other metallic materials retained after cardiac surgery m
ight represent a hazard to patients who undergo MR imaging, we sought
to determine the safety of such imaging.SUBJECTS AND METHODS. We exami
ned 200 patients who underwent MR imaging at 1 or 1.5 T after cardiac
surgery, Eighty-one were examined with ECG monitoring, The presence of
temporary epicardial pacing wires, prosthetic valves, and other metal
materials was confirmed by chest radiography. RESULTS. Of the 200 pat
ients reviewed, all had postoperative metallic material visible on che
st radiographs. Temporary epicardial pacing wire, cut short at the ski
n, was seen in 51 patients. Of the 81 patients examined with ECG monit
oring, we found that MR imaging produced no changes from baseline ECG
rhythms. None of the 200 patients reported symptoms suggesting arrhyth
mia or other cardiac dysfunction during MR imaging, CONCLUSION. MR ima
ging can be performed safely in patients who have undergone cardiac su
rgery and have retained metallic material, including valve replacement
s and temporary epicardial pacing wires cut short at the skin. MR imag
ing of patients with pacemakers was not evaluated, and we recommend th
at pacemakers remain a contraindication to MR imaging.