Vascular Neurology Symptoms and Risk Factors

Neurology diagnoses and treats disorders of the nervous system, including the brain, spinal cord, and nerves, as well as thought and memory.

Vascular Neurology: Diagnosis and Imaging

In the acute setting, the Non-Contrast Head CT (NCCT) remains the initial diagnostic workhorse. Its primary role is singular: to rule out hemorrhage. Blood appears bright white (hyperdense) on CT. If blood is present, clot-busting drugs are contraindicated.

While CT is insensitive to early ischemia (the stroke might not show up for 6-12 hours), early signs can sometimes be seen. The "Hyperdense Vessel Sign" indicates a visible clot inside an artery. The "ASPECTS" score is a systematic way of looking at the CT to quantify how much of the brain is already damaged, which helps guide treatment decisions.

• Rapid exclusion of intracranial hemorrhage
• Identification of Hyperdense MCA sign
• ASPECTS scoring of early ischemic change
• Loss of gray-white matter differentiation
• Detection of stroke mimics (tumors, subdural hematomas)

CT Angiography and Perfusion (multimodal CT)

Once hemorrhage is ruled out, the vascular tree must be mapped. CT Angiography (CTA) involves injecting contrast dye to visualize the arteries from the aortic arch to the vertex. This is critical for identifying Large Vessel Occlusions (LVO)—blockages in the main pipes that are accessible for mechanical removal.

CT Perfusion (CTP) is a functional scan. It measures how fast blood is moving through the brain tissue. It generates maps distinguishing the "core" (dead tissue, low blood volume) from the "penumbra" (starving tissue, delayed transit time). A large mismatch between core and penumbra indicates salvageable brain, justifying aggressive treatment even in delayed time windows.

• Visualization of vessel patency (CTA)
• Detection of Large Vessel Occlusion (LVO)
• Assessment of collateral flow quality
• Mean Transit Time (MTT) and Cerebral Blood Volume (CBV) maps
• Core-Penumbra mismatch analysis

Magnetic Resonance Imaging (MRI)

MRI is the gold standard for defining the infarct core. Diffusion Weighted Imaging (DWI) is a sequence sensitive to the movement of water molecules. In ischemic cells, the sodium pumps fail, water rushes in, and cellular swelling restricts water motion. This appears as bright signal on DWI within minutes of onset.

MRI is also essential for determining the "age" of a stroke. If a stroke is visible on DWI (cellular swelling) but invisible on FLAIR (fluid sequence), it indicates the stroke is less than 4.5 hours old. This "DWI-FLAIR mismatch" can qualify patients for thrombolysis even if they woke up with the stroke and the exact time of onset is unknown.

• Diffusion Weighted Imaging (DWI) sensitivity
• Apparent Diffusion Coefficient (ADC) confirmation
• DWI-FLAIR mismatch for wake-up strokes
• Gradient Echo (GRE/SWI) for microbleeds
• High-resolution vessel wall imaging

Ultrasonography (Carotid and Transcranial)

Ultrasound provides a dynamic assessment of blood flow without radiation. Carotid Duplex ultrasound assesses the arteries in the neck for atherosclerosis (plaque) and stenosis (narrowing). Velocity measurements can quantify the degree of blockage.

Transcranial Doppler (TCD) uses sound waves to penetrate the thin parts of the skull to measure flow velocity in the brain's arteries. It is used to monitor for vasospasm after subarachnoid hemorrhage, detect micro-emboli (HITS) passing through the circulation, and assess the patent foramen ovale (PFO) via a "bubble study."

• Assessment of carotid intima-media thickness
• Quantification of carotid stenosis velocity
• TCD monitoring for vasospasm
• Bubble study for right-to-left shunt (PFO)
• Emboli detection monitoring

Cardiac and Arrhythmia Monitoring

Since approximately 30% of strokes are cardioembolic (clots traveling from the heart), the heart is considered part of the neurovascular investigation. Transthoracic Echocardiogram (TTE) looks for structural thrombi or valvular vegetations. In some cases, a Transesophageal Echocardiogram (TEE) is needed to see the Left Atrial Appendage, a common hiding spot for clots in atrial fibrillation.

Detecting paroxysmal (intermittent) atrial fibrillation is a major diagnostic challenge. Standard EKGs often miss it. Vascular neurologists utilize long-term cardiac monitors—ranging from 30-day external Holter monitors to implantable loop recorders (ILRs) that sit under the skin for years—to catch these elusive rhythms.

• Transthoracic vs. Transesophageal Echocardiogram
• Left Atrial Appendage assessment
• Detection of Patent Foramen Ovale (PFO)
• Long-term cardiac rhythm monitoring (ILR)
• Evaluation of aortic arch atheroma