MRI of AIDS-related polyradiculomyelitis.

Objective: We describe the unusual syndrome of cytomegalovirus (CMV) polyradiculomyelitis and its MR findings in two patients with AIDS.

Materials And Methods: The clinical records and MRI studies of two patients with AIDS and CMV polyradiculomyelitis were reviewed. The MR images were performed on a Picker 1.0 or 1.5 T MR unit. Axial and sagittal T1-weighted images of the lumbar spine were obtained, pre- and post-Gd-DTPA (0.1 mmol/kg) administration. Gradient echo sagittal images were also obtained.

Results: Precontrast images demonstrated a thickened cauda equina in both patients. In one patient the conus was ill defined on precontrast images. Post-contrast images demonstrated diffuse enhancement of the cauda equina in both patients as well as enhancement along the surface of the conus. In one patient the nerve roots were clumped and adherent to the walls of the thecal sac as well as to other nerve roots.

Conclusion: The clinical presentation of urinary retention, flaccid paraparesis, back and/or leg pain, and "saddle anesthesia" in a patient with AIDS should suggest the diagnosis of CMV polyradiculomyelitis. Although diffuse enhancement of the cauda equina on postcontrast MRI is a nonspecific finding, it would strongly support this diagnosis in the appropriate clinical setting. The diagnosis may be easily missed without the use of a contrast agent.