VT Transcranial Doppler Imaging 2

Question 1

Which TCD parameter is most useful for detecting cerebral vasospasm after subarachnoid hemorrhage?

Accepted Answer

Mean flow velocity

Answer

Mean flow velocity (MFV) >120 cm/s in the MCA is the primary TCD criterion for detecting cerebral vasospasm after subarachnoid hemorrhage.

Question 2

The Lindegaard ratio is calculated by dividing MCA mean velocity by which vessel's velocity?

Accepted Answer

Extracranial internal carotid artery

Answer

The Lindegaard ratio = MCA MFV / ipsilateral extracranial ICA MFV, used to distinguish vasospasm from hyperemia.

Question 3

A Lindegaard ratio greater than 6 is most consistent with which condition?

Accepted Answer

Severe vasospasm

Answer

A Lindegaard ratio >6 indicates severe vasospasm, while a ratio <3 with elevated MCA velocity suggests hyperemia.

Question 4

During TCD monitoring for microemboli, what is the characteristic appearance of a HITS signal?

Accepted Answer

Unidirectional high-intensity transient signal lasting <300 ms

Answer

High-intensity transient signals (HITS) appear as unidirectional, brief (<300 ms) high-intensity signals at least 3 dB above background noise.

Question 5

Which acoustic window is used to insonify the basilar artery during TCD?

Accepted Answer

Suboccipital/transforaminal

Answer

The suboccipital (transforaminal) window provides access to the vertebral arteries and basilar artery through the foramen magnum.

(VT) Vascular Technician Certification Practice Test