For a 53‑year‑old man with a prior ischemic stroke, labile hypertension and new neck and left‑arm sensory symptoms after a normal non‑contrast head CT, should the next imaging be a CTA (computed tomography angiography) of the head and neck or an MRI (magnetic resonance imaging) brain with MRA (magnetic resonance angiography)?

Imaging Recommendation for Prior Stroke Patient with New Sensory Symptoms

Yes, you need MRI brain without contrast combined with MRA head and neck (preferably without contrast for the head, with contrast for the neck) as the next imaging step after a negative non-contrast head CT. 1, 2

Why MRI/MRA is the Appropriate Next Step

The negative head CT does not exclude acute ischemia or vascular pathology that could explain your symptoms. Non-contrast CT has only 16% sensitivity for detecting acute ischemic stroke in the first 3 hours, compared to 77% sensitivity for MRI with diffusion-weighted imaging (DWI). 2 Given your prior stroke history, labile hypertension, and new neck/arm sensory symptoms, you are at high risk for recurrent cerebrovascular events that require more sensitive imaging.

Key Clinical Concerns Your Symptoms Raise

Your constellation of symptoms—neck sensations plus left arm paresthesias in a patient with prior stroke and labile hypertension—raises three critical diagnostic possibilities:

• Recurrent ischemic stroke (particularly thalamic or brainstem stroke, which commonly presents with isolated sensory symptoms) 3, 4
• Cervical arterial dissection (neck pain/sensations with neurologic symptoms is a classic presentation) 1, 5
• Critical vascular stenosis requiring urgent intervention 1

Specific MRI Protocol Needed

Order: MRI brain without IV contrast + MRA head and neck 1, 2

The MRI protocol should include:

• Diffusion-weighted imaging (DWI) - detects acute ischemia within minutes with 91% sensitivity 2
• FLAIR sequences - identifies chronic lacunar infarcts and white matter disease 2
• Gradient-echo (GRE) or susceptibility-weighted imaging (SWI) - excludes hemorrhage and microbleeds 2
• MRA head without contrast (time-of-flight technique) - evaluates intracranial vessels for stenosis/occlusion 2, 6
• MRA neck with contrast - superior visualization of carotid bifurcation and extracranial vessels, critical for detecting dissection 1, 6

Why Not CTA?

While CTA head and neck is rated as "usually appropriate" for stroke evaluation 1, MRI/MRA is superior in your specific clinical scenario for several reasons:

• Better soft tissue characterization for detecting arterial dissection (the neck symptoms are particularly concerning for this) 1, 5
• No radiation exposure (important given you may need serial imaging for labile hypertension monitoring) 1
• Superior detection of small ischemic lesions that could explain isolated sensory symptoms 2, 3
• Can be performed as a single comprehensive study without requiring multiple separate acquisitions 2

Critical Pitfalls to Avoid

Do not assume the negative head CT rules out stroke. Sensory-only stroke syndromes, particularly from thalamic lesions, are frequently missed on CT but readily detected on MRI. 3 One study found that patients with pure sensory thalamic strokes had involvement of the nucleus ventrocaudalis in 89% of cases, and these small lesions are often invisible on CT. 3

Do not delay imaging while managing blood pressure. Your labile hypertension is likely a physiological response to cerebral ischemia rather than the primary problem. 7, 8 In acute ischemic stroke, elevated blood pressure often decreases spontaneously and should generally not be aggressively treated unless systolic BP exceeds 220 mmHg (or 185 mmHg if thrombolysis is being considered). 8

Do not dismiss sensory symptoms as "atypical" for stroke. Chest and arm sensory symptoms can mimic cardiac ischemia but may represent thalamic, corona radiata, or lateral medullary stroke. 4 In one series, 5 stroke patients presented with chest discomfort as a prominent sensory symptom that was initially mistaken for angina. 4

Timeline and Urgency

This imaging should be performed urgently (within 24 hours), not emergently. 1 While you are not in the hyperacute treatment window for thrombolysis, your symptoms suggest either:

• Ongoing ischemia requiring urgent intervention
• Arterial dissection at risk for propagation
• High-grade stenosis requiring revascularization

The American College of Radiology recommends that MRI/MRA ordered for stroke workup should be performed within 6 hours and interpreted within 2 hours during normal working hours. 1

What This Imaging Will Accomplish

The combined MRI/MRA will:

• Detect acute ischemia missed by CT (particularly small thalamic or brainstem strokes causing sensory symptoms) 2, 3
• Identify arterial dissection (the neck symptoms are a red flag for this) 1, 5
• Assess for high-grade stenosis requiring urgent revascularization 1
• Evaluate chronic small vessel disease related to your hypertension 9
• Guide secondary stroke prevention by identifying the stroke mechanism 1

Bottom line: The negative cardiac workup and head CT do not adequately explain your symptoms or exclude dangerous vascular pathology. MRI brain with MRA head and neck is the evidence-based next step to prevent a potentially devastating recurrent stroke. 1, 2