Does a patient with a history of possible Transient Ischemic Attack (TIA) 14 days prior to visit warrant an Magnetic Resonance Imaging (MRI) with and without contrast?

MRI Imaging for Possible TIA 14 Days After Event

For a patient presenting 14 days after a possible TIA, MRI of the brain WITHOUT contrast is warranted, but there is no evidence supporting the addition of contrast enhancement for routine TIA evaluation. 1

Key Imaging Recommendations

Brain Parenchymal Imaging

• MRI brain without contrast should be performed to identify any acute or subacute ischemic lesions that may have resulted from the TIA event, even at 14 days post-event 2
• Diffusion-weighted imaging (DWI) sequences remain positive in approximately 70% of minor strokes and 13% of TIAs when performed weeks after the event, making MRI valuable even with delayed presentation 3
• At 14-17 days post-symptom onset, DWI can still detect high-signal lesions and help clarify whether T2 abnormalities represent recent versus chronic ischemic changes 3

Contrast Enhancement Is NOT Indicated

• The American College of Radiology explicitly states there is no relevant literature supporting the use of contrast-enhanced MRA of the head in TIA evaluation 1
• Standard MRI brain without contrast is sufficient for detecting TIA-related infarcts 1
• Contrast enhancement contributed to delineation of acute lesions in only 2 of 45 patients (4%) in one study, demonstrating minimal added value 4

Complete Neurovascular Workup Beyond Brain MRI

Critical Additional Imaging Required

While you asked specifically about MRI with/without contrast, incomplete neurovascular imaging is associated with 30% increased odds of stroke within 90 days (OR 1.30,95% CI 1.23-1.38) 5. Therefore, the following should also be obtained:

• MRA head without contrast to evaluate for intracranial steno-occlusive disease 1
• MRA neck without contrast OR carotid duplex ultrasound to screen for extracranial carotid stenosis 1, 2
• These vascular studies should ideally have been performed within 48 hours of symptom onset per AHA guidelines, but remain important even at 14 days 1, 2

Clinical Context and Timing Considerations

Why This Matters at 14 Days

• The 90-day stroke risk after TIA ranges from 11.6% overall to 20.1% for carotid territory TIAs 2
• MRI at 14 days can reclassify up to 40% of suspected TIAs as clinically recovered ischemic strokes (CRIS), which changes therapeutic management 6
• Patients with MRI-confirmed infarction have significantly higher frequency of identifiable vascular or cardiac causes (odds ratio 5.2) requiring specific treatment 4

Common Pitfalls to Avoid

• Do not order MRI brain with AND without contrast for routine TIA evaluation—this adds cost, time, and gadolinium exposure without evidence of benefit 1
• Do not perform brain imaging alone—37.3% of TIA patients receive incomplete neurovascular workups, which is associated with worse outcomes 5
• Do not assume normal imaging at 14 days excludes significant pathology—DWI lesions persist for weeks and provide clinically useful information in 36% of delayed presentations 3

Recommended Imaging Protocol

Order the following studies:

1. MRI brain without contrast (including DWI sequences) 1, 2, 3
2. MRA head without contrast 1
3. MRA neck without contrast OR carotid duplex ultrasound 1, 2

Do NOT order:

• MRI brain with contrast 1
• MRI brain with AND without contrast 1
• MRA with contrast enhancement 1