How is a Stroke Diagnosed? Tests, Imaging & Next Steps
How is a Stroke Diagnosed?
A fast, accurate stroke diagnosis is what makes acute treatment and long-term recovery possible. Diagnosis begins the moment a patient reaches the emergency department and follows a predictable sequence of history, exam, labs, and imaging.
Step 1: History and Red Flags
The first step is a focused history. Physicians look for classic red flags for stroke:
- Sudden onset of symptoms
- Focal neurological findings, typically on one side of the body
- Time of last known well
- Personal or family history of clotting, atrial fibrillation, hypertension, or diabetes
Step 2: Neurological Exam
A bedside neurological exam checks cranial nerves, motor strength, sensation, coordination, and speech. Most emergency teams use the NIH Stroke Scale to quantify severity.
Blood Work and Laboratory Testing
Bloodwork helps rule out conditions that mimic a stroke and identifies contributing factors:
- Complete blood count and clotting time
- Blood glucose (severe low blood sugar can mimic a stroke)
- Electrolytes and kidney function
- Signs of infection
- Troponin, since heart attacks and strokes can occur together
Diagnostic Imaging for Stroke
CT Scan
A non-contrast CT scan is usually the first image because it quickly rules out a brain bleed and guides whether clot-busting medication is safe.
MRI
MRI, particularly diffusion-weighted imaging, shows damaged brain tissue within minutes of an ischemic stroke and is more sensitive than CT for small or brainstem strokes.
Carotid Ultrasound
This test looks for plaque narrowing the carotid arteries in the neck, a common source of embolic strokes.
Echocardiogram
An echocardiogram searches for clots inside the heart that can travel to the brain, especially in patients with atrial fibrillation.
CT or MR Angiography
Vascular imaging identifies large-vessel blockages that may be candidates for mechanical clot retrieval.
After the Diagnosis: Recovery and Rehabilitation
Once a stroke is confirmed, the treatment plan is tailored to the type (ischemic or hemorrhagic), location, and severity of the injury. Learn more about how stroke is treated and rehabilitated and review the symptoms of a stroke.
Our clinic provides comprehensive post-hospital functional neurology rehabilitation, including vestibular therapy, neuro-visual rehabilitation, and balance and gait training. Contact us to learn more.
Frequently Asked Questions
How long does it take to diagnose a stroke?
In a well-run stroke center, initial imaging and diagnosis usually occur within 25 to 45 minutes of arrival so that time-sensitive treatments can begin.
Can a stroke be missed on a CT scan?
Yes. Small strokes, brainstem strokes, and very early ischemic strokes may not be visible on the initial CT. MRI is more sensitive when the diagnosis is unclear.
What is a TIA and how is it diagnosed?
A transient ischemic attack has stroke-like symptoms that resolve within 24 hours. It is diagnosed with the same imaging workup and is considered a strong warning of a future stroke.
Can chiropractic neurology diagnose a stroke?
No. Acute stroke diagnosis requires an emergency medical setting. Functional neurology clinics play their role during rehabilitation after the hospital has stabilized the patient.