Leading the way
in Transcranial
Diagnostic Ultrasound


Power M-mode Transcranial Doppler with HDO™ Digital Processing

Transcranial Doppler Ultrasound

— Transcranial Doppler Applications —

Neurovascular Diagnostic Exams

Neurovascular TCD exams provide dynamic visualization of blood flow velocities and direction of flow in cerebral arteries. These exams are frequently used in conjunction with other imaging modalities to add real time blood flow monitoring through stenotic regions or in hemorrhagic vessels. The digital power M-Mode allows the operator to rapidly find windows and to see 64 mm of depth in a single view. This study is reimbursable under CPT code 93886, TCD - Complete Exam.

For further reading:

Applications and Advantages of Power Motion-Mode Doppler in Acute Posterior Circulation Cerebral Ischemia

Tsivgoulis G, Sharma VK, Hoover SL. - Stroke. 2008 Apr;39(4):1197-204. Epub 2008 Mar 6.

Full article available here.

A risk score to predict ischemic lesions after protected carotid artery stenting

Sharma Vk - J Neurol Sci. 2009 Feb 15;277(1-2):191-2; author reply 192-3.

Full article available here.

PFO Detection

Contrast TCD utilizing a measured Valsalva maneuver is an easy to perform test to detect Patent Foramen Ovale (PFO) and other right to left shunts. One of the advantages of TCD over TEE is the patient’s ability to perform an adequate valsalva strain. Utilizing the Spencer Technologies ST3 and Marc series headframe, the PFO/RLS test becomes a very straight forward study lasting generally less than 30 minutes. This study is reimbursable under CPT code 93893, TCD, Emboli detection with injection (Bubble Study).

For further reading:

Contrast transcranial Doppler ultrasound in the detection of right-to-left shunts: comparison of Echovist-200 and Echovist-300, timing of the Valsalva maneuver, and general recommendations for the performance of the test.

Droste DW, Jekentaite R, Stypmann J, et al. - Cerebrovasc Dis. 2002;13(4):235-41.

Full article available here.

Outcome of patients with cryptogenic stroke and patent foramen ovale foramen oval

Nedeltchev K, Arnold M, Wahl A, Sturzenegger M, et al. - J Neurol Neurosurg Psychiatry 2002;72:347–350

Full article available here.

Unilateral versus Bilateral Middle Cerebral Artery Detection of Right-to-Left Shunt by Power M-Mode Transcranial Doppler.

Jesurum JT, Fuller CJ, Moehring MA*, et al - J Neuroimaging. 2008 Sep 25. [Epub ahead of print]

Full article available here.

Migraine Headache Relief After Transcatheter Closure of Patent Foramen Ovale

Reisman M, Christofferson RD, Jesurum J et al - J Am Coll Cardiol. 2005 Feb 15;45(4):496-8.

Full article available here.

Patent Foramen Ovale and Cryptogenic Stroke in Older Patients

Handke M, Harloff A, Olschewski M, et al. - n engl j med 2007: 357;22

Full article available here.

Power M-Mode Transcranial Doppler for Diagnosis of Patent Foramen Ovale and Assessing Transcatheter Closure

Spencer MP, Moehring MA*, Jesurum J - J Neuroimaging. 2004 Oct;14(4):342-9

Full article available here.

*Dr. Moehring is an employee of Spencer Technologies.

Vasospasm (VSP) Monitoring

TCD has been shown to be effective in monitoring day to day velocity changes in cerebral circulation post cerebral aneurysm rupture or neuro-radiologic intervention. The Spencer Technologies ST3 has a high pulse repetition frequency (PRF) to accurately measure high blood flow velocities that are common with vasospasm. Additionally The Spencer Technologies ST3 has a unique multiday trend report specifically designed for tracking and reporting vasospasm. This study is reimbursable under CPT code 93888, TCD - Limited Exam.

Embolic Monitoring

Power M-mode is a valuable tool in detecting cerebral micro emboli (blood clot or air bubbles) due to a variety of pathologies including fibrillation or prosthetic valves. Another application for embolic monitoring is to identify asymptomatic carotid stenosis patients at high risk for stroke. With the Spencer Technologies HDO digital M-Mode, “embolic tracks” can be differentiated from artifact. This study is reimbursable under CPT code 93892, TCD, Emboli detection w/o injection.

For further reading:

Absence of Microemboli on Transcranial Doppler Identifies Low-Risk Patients With Asymptomatic Carotid Stenosis

Spence JD, Tamayo A, Lownie SP, et al. - Stroke. 2005 Nov;36(11):2373-8. Epub 2005 Oct 13.

Full article available here.

Emboli and Renal Dysfunction in CABG Patients

Edmonds HL Jr. - J Cardiothorac Vasc Anesth. 2004 Oct;18(5):545-7.

Full article available here.

Power M-mode Doppler (PMD) for observing cerebral blood flow and tracking emboli.

Moehring MA*, Spencer MP. - Ultrasound Med Biol. 2002 Jan;28(1):49-57.

Full article available here.

*Dr. Moehring is an employee of Spencer Technologies.

Intra-Operative Monitoring

Transcranial Doppler (TCD) is frequently used to monitor cerebral arteries for emboli and real time blood flow velocities during surgical procedures such as carotid endarterectomy, coronary artery bypass grafting and cerebral/carotid angioplasty or stenting. The Spencer Technologies’ patented Power M-Mode display is a highly sensitive method of detecting cerebral emboli. This study is reimbursable under CPT code 93892, TCD, Emboli detection w/o injection.

For further reading:

Determination of Cerebral Blood Flow Dynamics During Retrograde Cerebral Perfusion Using Power M-Mode Transcranial Doppler

Estrera AL, Garami Z, Miller CC 3rd, et al. - Ann Thorac Surg. 2003 Sep;76(3):704-9; discussion 709-10.

Full article available here.

Feasibility of simultaneous pre- and postfilter transcranial Doppler monitoring during carotid artery stenting.

Garami ZF, Bismuth J, Charlton-Ouw KM, et al. - J Vasc Surg. 2009 Feb;49(2):340-4, 345.e1-2; discussion 345.

Full article available here.

Vaso-Motor Reactivity

The ability of cerebral blood vessels to adapt to changes in metabolic demands of the brain can be measured using Transcranial Doppler. Stimuli such as CO2 inhalation, breath holding or the administration of acetazolamide will typically cause a vasodilatory response. This response can be measured by monitoring blood flow velocity changes with TCD. Patients whose vasomotor reserve is exhausted may be at risk for stroke or may not be candidates for some surgeries. This study is reimbursable under CPT code 93890, TCD Vasoreactivity Study.

Sickle Cell Anemia

TCD screening of children with sickle cell disease between the ages of 2 and 16 years has been proven effective for assessing stroke risk. The time-averaged mean maximum blood flow velocity of > 200 cm/s in the ICA or MCA by TCD is has been associated with stroke. In one study, transfusing these patients based on their blood flow velocity measurements resulted in a 92% reduction in stroke. This study is reimbursable under CPT code 93888, TCD - Limited or 93886, TCD - Complete Exam.

For further reading:

Clinical Alert from the National Heart, Lung, and Blood Institute


Letter available here.

Clinical Alert Issued to U.S. Physicians:
New Treatment Prevents Strokes In Children With Sickle Cell Anemia

National Heart, Lung, and Blood Institute

Letter available here.

Lytic therapy

Lytic therapy for cerebral blood vessels can be monitored with Transcranial Doppler to determine the point at which reperfusion occurs. This can help moderate the dosage of the lytic agent and reduce the risk of bleeding. While recent studies have suggested that the use of TCD may reduce the time to reprofusion, the therapeutic aspect of TCD remains under investigation. This study is reimbursable under CPT code 93888, TCD - Limited Exam.

Brain Death

Brain death is a clinical diagnosis and brain death exams performed with TCD are used as confirmatory tests. Using the Spencer Technologies ST3 for patients who are thought to be moving toward that diagnosis can help in the planning of other more costly exams and the use of TCD is especially helpful in examining patients on barbiturate therapy.This study is reimbursable under CPT code 93888, TCD - Limited or 93886, TCD - Complete Exam.

For further reading:

Ultrasonographic cerebral perfusion in assessment of brain death: a preliminary study.

Abadal JM, Llompart-Pou JA, Homar J, et al. - J Ultrasound Med. 2008 May;27(5):791-4.

Full article available here.

Brain Death and Disorders of Consciousness
Series: Advances in Experimental Medicine and Biology , Vol. 550

Machado, Calixto; Shewmon, D. Alan (Eds.), page 109

Book exceprt available here.