Removal of an orbital metallic foreign body to facilitate magnetic resonance imaging: technical case report.

OBJECTIVE AND

IMPORTANCE

Magnetic resonance imaging (MRI) is the imaging modality of choice for brain tumors and other lesions of the central nervous system. However, this procedure is contraindicated in patients with orbital metallic foreign bodies. In such cases, the usual clinical strategy is to manage the patient without the benefit of MRI scans and, instead, to rely on less sensitive imaging modalities in particular computed tomographic scanning.

CLINICAL PRESENTATION: Two patients, one with a posterior fossa mass and one with suspected central nervous system lymphoma, were seen at our institution. MRI scanning was recommended, but had been precluded in both patients by the presence of metal fragments in the orbit.

INTERVENTION: In each case, the orbital foreign body was successfully localized and removed. Postprocedure computed tomographic scanning confirmed complete removal. MRI scanning was then performed without difficulty. The first patient underwent posterior fossa craniotomy and removal of the tumor, which proved to be a medulloblastoma. The second patient was found to have evidence of lymphoma in the cranial base and meninges and was treated with radiotherapy and systemic and intrathecal chemotherapy. MRI scanning provided superior diagnostic information and spared both patients the risks and discomfort of myelography and exposure to ionizing radiation from multiple computerized tomographic scans.

CONCLUSION

Two patients with central nervous system tumors underwent removal of a metal fragment in the orbit for the specific purpose of facilitating MRI scans. This is a practical, straightforward concept, which should be considered when MRI scanning is needed for optimal patient management.