Transcranial Doppler
Non-invasive ultrasound assessment of cerebral blood flow velocities.
What is Transcranial?
Transcranial Doppler (TCD) uses ultrasound to measure blood flow velocity in major intracranial arteries through the skull.
How it works: Ultrasound waves penetrate the thin bone windows of the skull to measure blood flow velocities in real-time.
Common Uses of Transcranial
Stroke risk assessment
Identify patients with sickle cell disease at risk for stroke by detecting abnormal flow velocities.
Vasospasm detection
Monitor for cerebral vasospasm after subarachnoid hemorrhage, a serious complication.
Intracranial pressure assessment
Estimate intracranial pressure based on pulsatility indices in certain clinical scenarios.
Embolus detection
Detect microemboli circulating in the cerebral circulation, indicating potential sources of embolism.
Steno-occlusive disease evaluation
Assess for intracranial stenosis or occlusion in patients with suspected cerebrovascular disease.
Advantages
- ✓Non-invasive and portable
- ✓Real-time continuous monitoring capability
- ✓No ionizing radiation
- ✓Can be performed at bedside
- ✓Cost-effective compared to other neuroimaging
Limitations
- ⚠Operator dependent
- ⚠Limited acoustic windows
- ⚠Cannot visualize anatomy directly
- ⚠Flow velocity ≠ blood flow volume
- ⚠Less sensitive in older adults
Preparation Checklist
0 of 3 completed
⚖️Transcranial vs MRI
| Criteria | Transcranial | MRI |
|---|---|---|
| Speed | Moderate | Moderate |
| Radiation | No | Yes |
| Soft Tissue Detail | Limited | Excellent |
| Cost | High | High |
Related Imaging Modalities
MRI/CT for detailed anatomy; CTA/MRA for vascular imaging; conventional ultrasound for extracranial vessels.
MRI
MRI uses powerful magnets and radio waves to produce detailed images of organs and soft tissues. Excellent for brain, spine, and joint imaging.
CT
CT scans use X-rays to create detailed cross-sectional images of the body. They are particularly useful for detecting bone fractures, tumors, and internal bleeding.
Ultrasound
Ultrasound uses sound waves to create real-time images. Commonly used for pregnancy monitoring and examining organs like the heart, liver, and kidneys.
Browse Transcranial Terms
Explore common terms in Transcranial reports, each with detailed explanations, clinical significance, and related lab tests to help you understand your imaging results. lab tests.
Cerebral Vasospasm Transcranial Doppler: What It Shows, Cost
Elevated blood flow velocities with turbulence in intracranial arteries
Intracranial Stenosis Transcranial Doppler: What It Shows, C
Focal velocity elevation at stenosis with decreased velocities distal to narrowing
Right-to-Left Shunt Transcranial Doppler: What It Shows, Cos
Microbubbles detected in middle cerebral arteries after contrast injection
Sickle Cell Disease TCD Screening for Stroke Prevention: Wha
Elevated time-averaged mean maximum velocity (TAMMX) in major intracranial arteries, particularly middle cerebral artery
Brain Death Assessment with Transcranial Doppler: What It Sh
Characteristic flow patterns including oscillating flow, systolic spikes, or absent diastolic flow indicating cerebral circulatory arrest
Vasospasm Detection TCD After Subarachnoid Hemorrhage: What
Progressively elevated mean flow velocities in intracranial arteries with increased Lindegaard ratio, indicating arterial narrowing following subarachnoid hemorrhage
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