VT Transcranial Doppler Imaging 3

Question 1

During TCD-guided bubble study for patent foramen ovale (PFO), when should the patient perform the Valsalva maneuver?

Accepted Answer

5–10 seconds after injection, during release

Answer

The Valsalva maneuver should be released 5–10 seconds after injection to transiently raise right atrial pressure and maximize right-to-left shunt detection.

Question 2

A TCD study shows MCA mean velocity of 220 cm/s with a Lindegaard ratio of 2.5. This most likely represents:

Accepted Answer

Hyperemia

Answer

High MCA velocity with a low Lindegaard ratio (<3) indicates hyperemia rather than vasospasm, as extracranial ICA velocity is proportionally elevated.

Question 3

The normal depth range for insonating the MCA M1 segment via the transtemporal window is approximately:

Accepted Answer

35–60 mm

Answer

The MCA M1 segment is typically found at depths of 35–60 mm through the transtemporal window.

Question 4

Which TCD waveform feature is most indicative of downstream arterial occlusion (distal high resistance)?

Accepted Answer

Normal velocities with increased PI

Answer

Distal arterial occlusion creates high resistance outflow, manifesting as elevated pulsatility index (PI) with relatively preserved systolic but reduced diastolic velocity.

Question 5

In TCD assessment of cerebral autoregulation, the autoregulation index (ARI) is determined by measuring:

Accepted Answer

Dynamic response of MCA velocity to rapid blood pressure changes

Answer

The autoregulation index assesses the dynamic cerebrovascular response (MCA velocity changes) following rapid blood pressure perturbations such as thigh-cuff deflation.

(VT) Vascular Technician Certification Practice Test

(VT) Vascular Technician Certification Practice Test

VT Transcranial Doppler Imaging 3