MRI artifacts following anterior cervical diskectomy

BACKGROUND Magnetic resonance imaging (MRI), despite being an excellent imaging technique in neurosurgical practice, is unfortunately susceptible to numerous artifacts. Some of these artifacts are easily identifiable and do not interfere; however, others are more subtle and can be easily mistaken for false pathology. postoperative MRI can further complicate the imaging interpretation, by producing another group of artifacts. It is imperative for practicing neurosurgeons, as well as neuroradiologists, to have a clear understanding of these postoperative artifacts. METHODS We discuss four cases who had been operated for anterior cervical decompression with bony fusion. All the patients had apostoperative MRI of the cervical region that showed a ''false compression'' of the cervical cord. The normal computed tomography (CT) scan in some cases and the discrepancy with the clinical condition of the patients excluded the diagnosis of compression of the cervical cord. RESULTS The overall appearance of the postoperative MRI can be very difficult to interpret. The artifact seen following anterior cervical diskectomy is an example of such a situation. We have confirmed that the postoperative MRIs showing artifacts do not indicate cord or root compression; a routine postoperative plain X ray or CT scan of the operated area can also confirm the absence of compression. CONCLUSION These are examples of cases in which the postoperative MRI had an unexpected metallic artifact that not only caused difficulty in the interpretation of the images but at times suggested a clinical problem when actually there was none. Very thin cut CT scans may not show these artifacts that are picked up by the sensitive MRI study. A proper clinical evaluation and selection of the appropriate MRI techniques and the MRIs can eliminate or at least decrease the incidence of the artifacts. Above all, further education of practicing physicians is needed to avoid false alarms caused by these metallic artifacts. (C) 1997 by Elsevier Science Inc.