Magnetic resonance imaging evaluation after implantation of a titanium cervical disc prosthesis: a comparison of 1.5 and 3 Tesla magnet strength.
OBJECTIVE
Cervical disc prostheses induce significant amount of artifact in magnetic resonance imaging which may complicate radiologic follow-up after surgery. The purpose of this study was to investigate as to what extent the artifact, induced by the frequently used Discover(®) cervical disc prosthesis, impedes interpretation of the MR images at operated and adjacent levels in 1.5 and 3 Tesla MR.


METHODS
Ten subsequent patients were investigated in both 1.5 and 3 Tesla MR with standard image sequences one year following anterior cervical discectomy with arthroplasty.


METHODS
Two neuroradiologists evaluated the images by consensus. Emphasis was made on signal changes in medulla at all levels and visualization of root canals at operated and adjacent levels. A "blur artifact ratio" was calculated and defined as the height of the artifact on T1 sagittal images related to the operated level.


RESULTS
The artifacts induced in 1.5 and 3 Tesla MR were of entirely different character and evaluation of the spinal cord at operated level was impossible in both magnets. Artifacts also made the root canals difficult to assess at operated level and more pronounced in the 3 Tesla MR. At the adjacent levels however, the spinal cord and root canals were completely visualized in all patients. The "blur artifact" induced at operated level was also more pronounced in the 3 Tesla MR.


CONCLUSIONS
The artifact induced by the Discover(®) titanium disc prosthesis in both 1.5 and 3 Tesla MR, makes interpretation of the spinal cord impossible and visualization of the root canals difficult at operated level. Adjusting the MR sequences to produce the least amount of artifact is important.
Department of Neurosurgery, Oslo University Hospital Rikshospitalet, Oslo, Norway, jsundset@ous-hf.no.
Jarle
J
Sundseth
Eva A
EA
Jacobsen
Frode
F
Kolstad
Oystein P
OP
Nygaard
John A
JA
Zwart
Per K
PK
Hol
D000328:Adult; D016477:Artifacts; D001672:Biocompatible Materials; D002574:Cervical Vertebrae / Q000473:pathology / Q000601:surgery*; D017586:Diskectomy; D005260:Female; D006801:Humans; D007403:Intervertebral Disc / Q000473:pathology / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D059346:Magnets; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D016032:Randomized Controlled Trials as Topic; D013116:Spinal Cord / Q000473:pathology; D013126:Spinal Nerve Roots / Q000473:pathology; D014025:Titanium; D059145:Total Disc Replacement
D001672:Biocompatible Materials; D014025:Titanium