A transcranial Doppler report describes blood flow velocities in the arteries inside your skull, compared with expected ranges and between the two sides. Raised velocities generally suggest narrowing; reduced or absent signals suggest blockage or a technical limitation.
A transcranial Doppler report describes blood flow velocities in the arteries inside your skull, compared with expected ranges and between the two sides. Raised velocities generally suggest narrowing; reduced or absent signals suggest blockage or a technical limitation.
The study measures how fast blood moves through each artery it can reach. When a vessel narrows, blood must speed up to pass through the narrower segment, so raised velocity is the main indicator of stenosis. The report lists each vessel examined with its measured velocity, and compares against expected ranges. Direction of flow is also recorded, because reversed flow in a vessel can indicate that blood is being diverted around a blockage elsewhere.
As with most paired studies, asymmetry between your two sides is often more meaningful than an absolute number, since normal ranges are wide. The report may also note that a vessel could not be adequately examined. That is usually a technical limitation rather than an abnormal finding: ultrasound has to pass through thin areas of the skull called acoustic windows, and in some people, particularly with increasing age, those windows are poor. An inadequate window is not the same as an abnormal result.
Transcranial Doppler examines arteries inside the skull. Carotid ultrasound examines the larger arteries in the neck, and the two answer different questions and are often used together. Transcranial Doppler is performed at both CNS offices and interpreted by the ordering neurologist; carotid ultrasound is arranged at an imaging facility since these offices have no imaging suite. Neither replaces clinical assessment, and results are discussed against your history.
Clinical Neurology Specialists has been physician-owned since 1998, when Leo Germin, M.D., FAANEM founded it. Five board-certified neurologists and four advanced practice providers see patients at the Las Vegas and Henderson offices, each with its own AANEM-accredited electrodiagnostic laboratory.
Clinical Neurology Specialists is an adult outpatient neurology practice for patients 18 and older. The practice performs no surgery and operates no imaging suite, infusion suite or interventional pain programme, and provides no emergency or inpatient care.
Physician-reviewed. Reviewed by the physicians of Clinical Neurology Specialists — board-certified neurologists, AANEM-accredited electrodiagnostic laboratories, physician-owned since 1998. Reviewed 1 August 2026. This article is general education for adults 18 and older and is not a substitute for a consultation.
Sources and further reading: National Institute of Neurological Disorders and Stroke; MedlinePlus: carotid artery disease; American Academy of Neurology.
Adults 18 and older, at the Las Vegas and Henderson offices. Call 702-804-1212 or request an appointment online.