Subacute combined degeneration

Findings

Figure 2 and Figure 4: Sagittal and axial T2-weighted images demonstrate symmetrical hyperintensity within the dorsal columns that is contiguous in length over several vertebral body lengths.
Figure 1 and Figure 3: Sagittal T1-weighted images pre and post-gadolinium demonstrate hypointense signal within the dorsal cervical spinal cord without enhancement.


Diagnosis: Subacute combined degeneration


MR findings in subacute combined degeneration include symmetrical increased signal intensity in T2-weighted sequences along the dorsal columns that is usually contiguous over multiple vertebral body lengths.
The differential diagnosis includes B12 deficiency with subacute combined degeneration, tabes dorsalis and vacuolar myelopathy in AIDS.

Vitamin B12 deficiency causes a wide range of neurological, hematological and gastrointestinal disorders. Subacute combined degeneration is one such neurological disorder that is characterized by symmetrical numbness, weakness and paresthesia. It most commonly results from pernicious anemia and is potentially reversible with B12 supplementation.

MR findings include symmetrical increased signal intensity on T2-weighted sequences along the dorsal columns that is usually contiguous over multiple vertebral body lengths. Lesions are iso or hypointense to the normal cord on precontrast T1-weighted sequences. There can be variable contrast enhancement. The differential diagnosis includes tabes dorsalis and vacuolar myelopathy in AIDS. These can be distinguished from other myelopathies on the bases of their symmetry and contiguous cord level involvement. They can be differentiated from each other on the basis of laboratory tests and clinical history.