How is spinal cord infarction diagnosed in a patient with sudden severe back or neck pain, rapid onset focal neurological deficits, and vascular risk factors such as hypertension, diabetes, atherosclerosis, recent aortic surgery, anticoagulation, or embolic sources?

Diagnosis of Spinal Cord Infarction

MRI of the entire spine without contrast is the diagnostic imaging modality of choice for suspected spinal cord infarction, though initial imaging within the first 12-24 hours may be falsely negative in up to 24% of cases, requiring repeat MRI at 48-72 hours if clinical suspicion remains high. 1, 2

Clinical Recognition: The Foundation of Diagnosis

The diagnosis of spinal cord infarction begins with recognizing the characteristic clinical pattern that overrides initial negative imaging:

• Rapid onset to nadir within 12 hours is the strongest clinical predictor, occurring in 77% of spontaneous cases 1
• Severe focal neurological deficits developing while the patient is active, with smooth progression over minutes to hours 1, 3
• Peri-onset focal pain in the back, neck, trunk, or limbs occurs in 64-68% of cases 1, 4
• Dissociative sensory loss (selective pain/temperature impairment with preserved proprioception) is present in 39-60% of patients 1, 4

A clinical presentation consistent with acute myelopathy and vascular risk factors overrides an initially negative MRI and should not delay appropriate management. 2

MRI Imaging Protocol and Timing

Initial Imaging (Within 12 Hours)

• MRI spine without IV contrast is the preferred initial study, allowing detailed assessment of soft tissues, vertebral marrow, and spinal canal patency 5
• Expect false negatives: Initial MRI is normal in 24% of cases because T2 changes develop over hours to days 1, 2
• Include diffusion-weighted imaging (DWI): Restricted diffusion appears as early as 8 hours and provides the highest diagnostic yield in the hyperacute phase 2, 6, 4

Repeat Imaging (48-72 Hours)

If initial MRI is negative but clinical suspicion remains high, repeat MRI at 48-72 hours is mandatory. 2

The delayed imaging reveals characteristic patterns:

• "Owl eyes" sign (bilateral anterior horn hyperintensity) in 65% of cases 1
• "Pencil-like" hyperintensity (longitudinal T2 signal in central cord) in 40% of cases 1, 2
• Longitudinally extensive lesions spanning multiple segments in 68% of cases 1, 4
• Anterior spinal artery territory involvement (transverse infarction 52.5%, ASA territory 27.5%) 4

Confirmatory MRI Features

Beyond the characteristic T2 patterns, look for these supportive findings:

• DWI/ADC restriction present in 67% when performed, lasting up to 60 days in some cases 1, 4
• Linear gadolinium enhancement in anterior gray matter (39% of cases) 1
• Adjacent vertebral body infarction in 9-25% of cases 1, 4
• Ventral cauda equina enhancement in 14% 4
• Weakened enhancement of dorsal venous plexus in 45% 4

Vascular Imaging for Etiology

Once spinal cord infarction is confirmed, vascular imaging identifies the underlying cause:

• CTA of neck and chest if arterial dissection, aortic pathology, or atherosclerotic disease is suspected based on risk factors 5
• MRA of neck can detect vertebral artery dissection with 77% sensitivity, particularly when combined with fat-suppressed T1 sequences to visualize mural hematoma 5, 7, 8
• CTA has 100% sensitivity for vertebral artery dissection and is preferred over MRA when dissection is the primary concern 7, 8

Adjunctive Diagnostic Tools

Evoked Potentials (Hyperacute Phase)

Motor and sensory evoked potentials can provide diagnostic confirmation before DWI becomes positive. 6

• Central motor conduction time (CMCT) shows abnormalities in 100% of tested cases, with motor evoked potentials completely absent in 75% 6
• Somatosensory evoked potentials (SEP) are abnormal in 90% of cases 6
• Timing advantage: EP abnormalities are more profound in spinal cord infarction than transverse myelitis, even when performed earlier 6

Cerebrospinal Fluid Analysis

• Mild inflammation occurs in only 8% of cases, helping distinguish from inflammatory myelopathies 1
• Normal CSF does not exclude spinal cord infarction 1

Proposed Diagnostic Criteria

Definite spontaneous spinal cord infarction requires: 1

1. Acute myelopathy with rapid onset (typically <12 hours to nadir)
2. Absence of cord compression on MRI
3. MRI showing characteristic patterns (owl eyes, pencil-like hyperintensity, or DWI restriction in appropriate vascular territory)
4. Confirmatory findings: vertebral body infarction, adjacent vessel dissection/occlusion, or DWI/ADC restriction

Probable spontaneous spinal cord infarction requires: 1

1. Acute myelopathy with rapid onset
2. Absence of cord compression on MRI
3. Characteristic MRI T2 patterns without confirmatory findings
4. Vascular risk factors present

Critical Pitfalls to Avoid

• Do not dismiss the diagnosis with negative initial MRI: 24% of cases have normal imaging in the first 12-24 hours 1, 2
• Do not wait for imaging to start management: If clinical suspicion is high, initiate appropriate care while awaiting confirmatory imaging 2
• Do not confuse with transverse myelitis: Spinal cord infarction has more rapid onset, dissociative sensory loss, and peri-onset pain; CSF is typically normal 1, 6
• Do not forget to image the entire spine: Lesions can occur at any level, with 92.5% occurring at T8-L2 or C4-T4 4
• Do not overlook vertebral body infarction: This finding in 9-25% of cases strongly supports the diagnosis 1, 4