Neurology · MU Sofia

27. Ultrasound

Introduces ultrasound as a non-invasive, radiation-free way to assess blood flow in cerebral and cervical vessels, then covers carotid duplex imaging and transcranial Doppler, naming the arteries each examines. It explains the Doppler principle and how flow velocity, direction and stenosis are measured, lists clinical indications such as carotid stenosis, stroke and vasospasm, and closes with the main findings and the advantages and limitations of the method.

Inside: 1 section · 15 flashcards · 1 min

Topic 27 of 88 in the MU Sofia syllabus for Neurology (Medicine, Year 4). The free AceMed note covers it in 1 section, about 191 words (1 min of reading), with 15 flashcards.

In this note

  1. Ultrasound

Ultrasound

Definition: Ultrasound (US) is a non-invasive imaging method that uses high-frequency sound waves to visualize blood vessels and assess blood flow in the nervous system.

  • It is mainly used to evaluate cerebral and cervical circulation.

Types of Neurological Ultrasound

1. Carotid Duplex Ultrasound

Combines:

  • B-mode imaging (vessel anatomy)
  • Doppler ultrasound (blood flow)

Examines: Common carotid artery. Internal carotid artery. External carotid artery. Vertebral arteries

2. Transcranial Doppler (TCD)

Assesses blood flow in intracranial arteries: Middle cerebral artery (MCA). Anterior cerebral artery (ACA). Posterior cerebral artery (PCA). Basilar artery

Principle (Doppler Effect)

Movement of red blood cells changes the frequency of reflected ultrasound waves.

This allows measurement of: Blood flow velocity. Direction of blood flow. Vascular stenosis or occlusion

Clinical Indications

1. Cerebrovascular Disease: Carotid stenosis. Carotid occlusion. Stroke and TIA evaluation

2.Intracranial Vascular Disorders: Vasospasm after subarachnoid hemorrhage. Intracranial stenosis

Monitoring: Cerebral circulation. Emboli detection

Main Findings

  • Stenosis: Increased flow velocity. Turbulent blood flow
  • Occlusion: Absent blood flow signal
  • Vasospasm: Markedly increased flow velocity

Advantages: Non-invasive. Safe. Painless. No radiation. Can be repeated frequently. Bedside examination possible

Limitations

  • Operator-dependent
  • Limited visualization of deep brain structures
  • Bone may interfere with transcranial examination

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