Study
Complete Circle Evaluation
Vasoreactivity study
Emboli detection without IV microbubble injection
Emboli detection with IV microbubble injection
Limited evaluation
CPT Code
93886
93890
93892
93893
93888
Complete Circle Evaluation
An in-depth evaluation of mean flow velocity(MFV) of the entire Circle of Willis. Sample MVF recordings are acquired that can be helpful in assessing stenosis, occlusion, and compensatory flow in setting of a proximal occlusion.
Vasoreactivity study
Used to assess a patients cerebral autoregulatory capacity in order to help determine a patients risk for stroke. This test is performed with a 30-second breath-hold to monitor changes in MFV of unilateral or bilateral middle cerebral arteries. A Breath Holding Index (BHI) is obtained through simple calculations dependent on each individual study parameters.
Emboli detection without IV microbubble injection
A 30-minute recording of a vessel of interest to assess for potential on-going embolic activity in the setting of stroke or TIA patients. A critical component to assure stroke aftercare is maximized. A valuable too in assessing risk for patients with any degree of carotid plaque.
Emboli detection with IV microbubble injection
Another valuable study in top stroke-patient care is evaluating the presence and degree of a left to right shunt also known as a patent foramen ovale (PFO). Multiple injections of agitated saline are used in secession with MCA monitoring
Limited evaluation
The main limitation to TCD is Hyperostosis hindering insonation of arteries. In this case a limited evaluation can be performed of the bilateral vertebral and basilar arteries, as well as terminal ICA and opthalmic arteries if necessary. This could also be necessary due to patient tolerance abilities.
An example of a complete Circle of Willis Evaluation in a healthy patient. Each vessel is assessed for MFV and direction of flow. Waveform morphology can also provide valuable information regarding your patients perfusion. Although not pictured, each vessel is sampled along the entire visible length to ensure there are no areas of stenosis or other abnormalities.
In this image we see an example of a normal emboli-detection study performed over a period of 30-minutes. A technologist is present during the entire time listening in conjunction with the machines automated system for Hyper-Intense Transient Signals (HITS). HITS determine the presence of ongoing embolic activity in a specific vessels which can help dial in your patients care.
During a Vasoreactivity exam a baseline recording of either the unilateral or bilateral middle cerebral artery is taken after a period of rest. The patient is instructed to hold their breath to the best of their abilities for a period of 30-seconds. A MFV is recorded at the start of the breath hold and then again at the end. Using a simple formula we are able to provide a Breath Hold Index, In the example to left the BHI would be 0.90, VMR impairment is noted when BHI is less than 0.69.