### Abstract

Transcranial Doppler sonography (TCD) was first introduced by Rune Aaslid and colleagues in 1982 to non-invasively measure blood flow velocities in the major branches of the Circle of Willis through the intact skull.1 A 2-MHz frequency pulse wave ultrasonic beam penetrates the skull and allows returned echo signals to be detected. The frequency shift of the returned echoes is calculated using the Doppler equation f_{D} = 2 f_{o} v cosθ/(c - cosθ), where f_{D} is Doppler shift, f_{o} is the emitting frequency, v is the scatterer speed, θ is the Doppler angle, and c is the sound propagation speed. The average speed of sound in soft tissues is 1540 m/s and the Doppler angle for TCD examination is assumed to be 0° for all arteries (cos 0° = 1). Therefore the Doppler equation is rearranged to calculate the velocity of moving blood in basal cerebral arteries: v(cm/s) = 77 f_{D} (kHz)/f_{o} (MHz), where the 77 coefficient is valid for frequency and velocity units shown in parentheses.

Original language | English (US) |
---|---|

Title of host publication | Noninvasive Vascular Diagnosis |

Subtitle of host publication | A Practical Guide to Therapy: Second Edition |

Publisher | Springer London |

Pages | 103-126 |

Number of pages | 24 |

ISBN (Print) | 1846284465, 9781846284465 |

DOIs | |

State | Published - Dec 1 2007 |

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### All Science Journal Classification (ASJC) codes

- Medicine(all)

### Cite this

*Noninvasive Vascular Diagnosis: A Practical Guide to Therapy: Second Edition*(pp. 103-126). Springer London. https://doi.org/10.1007/978-1-84628-450-2_9

**Transcranial doppler sonography.** / Ribo, Marc; Alexandrov, Andrei.

Research output: Chapter in Book/Report/Conference proceeding › Chapter

*Noninvasive Vascular Diagnosis: A Practical Guide to Therapy: Second Edition.*Springer London, pp. 103-126. https://doi.org/10.1007/978-1-84628-450-2_9

}

TY - CHAP

T1 - Transcranial doppler sonography

AU - Ribo, Marc

AU - Alexandrov, Andrei

PY - 2007/12/1

Y1 - 2007/12/1

N2 - Transcranial Doppler sonography (TCD) was first introduced by Rune Aaslid and colleagues in 1982 to non-invasively measure blood flow velocities in the major branches of the Circle of Willis through the intact skull.1 A 2-MHz frequency pulse wave ultrasonic beam penetrates the skull and allows returned echo signals to be detected. The frequency shift of the returned echoes is calculated using the Doppler equation fD = 2 fo v cosθ/(c - cosθ), where fD is Doppler shift, fo is the emitting frequency, v is the scatterer speed, θ is the Doppler angle, and c is the sound propagation speed. The average speed of sound in soft tissues is 1540 m/s and the Doppler angle for TCD examination is assumed to be 0° for all arteries (cos 0° = 1). Therefore the Doppler equation is rearranged to calculate the velocity of moving blood in basal cerebral arteries: v(cm/s) = 77 fD (kHz)/fo (MHz), where the 77 coefficient is valid for frequency and velocity units shown in parentheses.

AB - Transcranial Doppler sonography (TCD) was first introduced by Rune Aaslid and colleagues in 1982 to non-invasively measure blood flow velocities in the major branches of the Circle of Willis through the intact skull.1 A 2-MHz frequency pulse wave ultrasonic beam penetrates the skull and allows returned echo signals to be detected. The frequency shift of the returned echoes is calculated using the Doppler equation fD = 2 fo v cosθ/(c - cosθ), where fD is Doppler shift, fo is the emitting frequency, v is the scatterer speed, θ is the Doppler angle, and c is the sound propagation speed. The average speed of sound in soft tissues is 1540 m/s and the Doppler angle for TCD examination is assumed to be 0° for all arteries (cos 0° = 1). Therefore the Doppler equation is rearranged to calculate the velocity of moving blood in basal cerebral arteries: v(cm/s) = 77 fD (kHz)/fo (MHz), where the 77 coefficient is valid for frequency and velocity units shown in parentheses.

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U2 - 10.1007/978-1-84628-450-2_9

DO - 10.1007/978-1-84628-450-2_9

M3 - Chapter

SN - 1846284465

SN - 9781846284465

SP - 103

EP - 126

BT - Noninvasive Vascular Diagnosis

PB - Springer London

ER -