MR findings in AIDS-associated myelopathy

Abstract

Background and purpose: The most common cause of spinal cord disease among patients with AIDS or those infected with HIV-1 is AIDS-associated myelopathy. The purpose of this study was to determine the MR characteristics of the spinal cord in this patient population and to correlate these findings with the clinical severity of myelopathy.

Methods: MR images of the spinal cord in 21 patients with documented HIV-1 infection or AIDS and a clinical diagnosis of AIDS-associated myelopathy were assessed retrospectively for atrophy, intrinsic signal abnormality, and abnormal enhancement. The clinical severity of myelopathy was graded by a neurologist on the basis of physical examination, and a qualitative correlation was made with the MR findings.

Results: MR findings were abnormal in 18 of the 21 patients. The most common feature was spinal cord atrophy (n = 15), typically involving the thoracic cord with or without cervical cord involvement, followed by intrinsic cord signal abnormality (n = 6), and normal-appearing cord (n = 3). Three patients had both cord atrophy and intrinsic cord signal abnormality. The cord signal abnormality was diffuse, without predilection for any specific distribution pattern. Enhancement was not seen in any of the 10 patients who received intravenous contrast material. Only one of 16 patients with moderate to severe myelopathy had normal MR findings, as compared with two of five patients with mild myelopathy.

Conclusion: MR findings in the spinal cord are abnormal in the majority of patients with AIDS-associated myelopathy, typically showing spinal cord atrophy, with or without intrinsic cord signal abnormality. Patients with moderate to severe myelopathy have an increased frequency of spinal cord abnormalities, but a definite correlation between clinical severity of myelopathy and extent of MR abnormalities remains to be established.

fig 1.

A–C, T1-weighted sagittal (A), T2-weighted sagittal (B), and T2-weighted axial (C) MR images through the thoracic spine of an AIDS patient with mild myelopathy show cord atrophy and intramedullary cord signal abnormality

fig 2.

A–C, Sagittal T1-weighted (A), sagittal T2-weighted (B), and axial T2-weighted (C) MR images of the cervical spine in a patient with severe myelopathy show cervical cord atrophy and extensive abnormal intrinsic cord signal intensity

fig 3.

A and B, Noncontrast sagittal T1-weighted (A) and T2-weighted (B) images show a normal-sized cervicothoracic cord with intramedullary thoracic cord signal abnormality and no associated cord enlargement. There was no evidence of abnormal enhancement in the postcontrast study (not shown)

fig 4.

A, Luxol fast blue stain of the spinal cord in a patient with AIDS-associated myelopathy (not from our series) shows pathologic changes predominantly involving the posterior and lateral columns (arrows). B, A magnified view of the same specimen as in A shows vacuolization (small arrows) and lipid-laden macrophages (large arrows) scattered throughout the involved cord. (Reprinted with permission from Mandell GL. Atlas of Infectious Diseases, I: AIDS. 2nd ed. Philadelphia: Current Medicine, Inc; 1997.)