TCD is a noninvasive and painless ultrasound method that uses sound waves to evaluate blood flow in and around the brain. There is no special contrast or radiation involved in the test. During the TCD exam, high frequency sound waves are transmitted through the tissues of the skull. These sound waves reflect off blood cells moving within the blood vessels, allowing the TCD system to measure the rate and direction of blood flow in the main cerebral arteries known as the Circle of Willis. While most forms of ultrasonography deliver images of the tissue studied, TCD delivers audible sounds that can be heard, recorded, and examined.
Physicians recommend this highly accurate and sensitive test for patients with stroke or stroke-like symptoms. It is used to diagnose of a wide range of conditions affecting blood flow to, and within, the brain.
Detection and evaluation of cerebral vasospasm after spontaneous or traumatic subarachnoid hemorrhage.
Intraoperative and perioperative monitoring of intracranial flow velocity and hemodynamic patterns during carotid endarterectomy, carotid stenting, or other high-risk surgeries.
Detection of free-floating particles in the bloodstream, known as emboli, which are a significant source of stroke risk.
Assessment of vasomotor reactivity to determine if the small vessels that regulate blood flow to the brain are working properly.
Assessment of right to left shunting through a bubble study.
There are five CPT codes covering TCD testing
Similar to other ultrasound-based tests, TCD uses sound waves to evaluate structures inside the body, in this case the blood flow in the brain. However, the brain is protected by the skull and ultrasound waves cannot easily pass-through bone. TCD testing requires the operator to be able to find the transtemporal window (thin part of the bone in the skull) that will allow the ultrasound waves to penetrate the skull and find the blood vessels that need to be evaluated. Finding this window is one of the most difficult parts of the exam. It is unique to this form of ultrasound, resulting in a high learning curve compared to other ultrasound tests.
Because of the lack of TCD-trained healthcare professionals, many hospitals are not able to provide TCD testing for their patients.
The NovaGuide Intelligent Ultrasound is an FDA cleared, AI-driven, robotic TCD system. Any healthcare practitioner can be taught how to set up the system and perform the exam. Offering secure, cloud-based access to exam data, NovaGuide View allows clinical specialists to view exam images and videos, add interpretations, and complete reports.
The NovaGuide system autonomously finds the temporal window. Once the transtemporal window is identified, an algorithm finds and locks onto the strongest cerebral blood flow signal. The algorithm was designed to mimic the search of a TCD sonographer, but responds to real-time data rather than being a fixed search pattern. The signal acquisition time and signal accuracy of NovaGuide has been shown to be comparable to an expert TCD sonographer.4
This can only be done with a 5 degree of freedom (DOF) system. Semi-automated solutions cannot perform this mapping.
Through thousands of cases and with the world’s largest cerebral blood flow data set, NovaSignal has been able to map the temporal bone for locations of signal acquisition.
Download Increasing Exam Accuracy and Efficiency through AI-Driven, Robotic TCD Ultrasound to discover how the autonomous, robotic NovaGuide Intelligent Ultrasound broadens access to TCD for hospitals with no expertise, while also increasing exam accuracy and efficiency.