TRANSCRANIAL DOPPLER (TCD) ULTRASOUND MED202.047 BlueReview POSTED DATE: 11/17/2003 EFFECTIVE DATE: 10/24/2003 _____________________________________________________________________________ COVERAGE: Transcranial Doppler (TCD) Ultrasound is considered medically necessary when used for the following: · Assessing for vasoconstriction such as in patients with subarachnoid hemorrhage; · Reviewing for severe stenosis in the carotid, vertebral and circle of Willis arteries; · Evaluating patterns and degrees of collateral circulation where identified areas of severe occlusion occur as in carotid endarectomy or intracranial atherosclerosis; · Determining risk in patient for transient ischemic attacks (TIA) or cerebrovascular accidents(CVA); · Identifying arteriovenous malformations (AVMs) and following flow patterns; or, · Assessing suspected brain death. TCD is considered investigational and experimental when used in following indications: · Evaluation of hemodynamic importance of extracranial atherosclerosis; · Monitoring cerebral blood flow following trauma; · Assessing migraine and tension headaches; · Reviewing cerebral blood velocity during cardiopulmonary bypass surgery and embolic events; · Evaluating blood flow patterns in central nervous system infections; · Assessing dementia; or · Evaluating glaucoma. ______________________________________________________________________ DESCRIPTION: Blue Cross and Blue Shield of Texas, a Division of Health Care Service Corporation, a Mutual Legal Reserve Company* Southwest Texas HMO, Inc.* d/b/a HMO BlueÒ Texas * Independent Licensees of the Blue Cross and Blue Shield Association TRANSCRANIAL DOPPLER (TCD) ULTRASOUND MED202.047 BlueReview POSTED DATE: 11/17/2003 EFFECTIVE DATE: 10/24/2003 _____________________________________________________________________________ TCD ULTRASOUND is a non-invasive modality for imaging blood flow in cerebral arteries and veins. In TCD, a probe placed over the skull generates ultrasonic waves. The bony plate of the skull limits TCD measurements to three primary sites (or acoustic windows). The sites are: · Temporal bone along the orbito-meatal line (the opening of the boney cavity that contains the eyeball); · Optic foramina (a passage through the bone for the eye); and, · Foramen magnum (the large opening in the inferior and anterior part of the occipital bone interconnecting the vertebral canal and the cranial cavity) at the base of the skull. Sound waves transmitted through these windows are reflected by blood in the intracranial vasculature. The frequency shift of the reflected sound waves recorded at the probe is used to estimate blood flow velocity or volume. ______________________________________________________________________ RATIONALE: Routine TCD examination of the intracranial arteries was demonstrated to be possible in 1982. TCD is primarily a technique for measuring relative changes in flow. One fact that has to be constantly kept in mind when utilizing TCD is that the value obtained for a particular artery is the velocity of blood flowing through the vessel, and unless the diameter of the vessel is established by other means it is not possible to determine the actual blood flow. The American Academy of Neurology technology assessment report published in 1990 stated that TCD established value in the assessment of patients with intracranial stenosis, collateral circulation, subarachnoid hemorrhage, and brain death. A panel of international experts reviewed the literature published up to 1998 and ranked the specific clinical applications of TCD based on the strength and quality of published evidence. This review sustained the position by the Academy in 1990. ______________________________________________________________________ PRICING: Since TCD Ultrasound (93886 or 93888) and magnetic resonance angiography of the head (70541) use different physical and technical principles for evaluating the cerebral vasculature, the information obtained from each test can be complementary rather than duplicative. Blue Cross and Blue Shield of Texas, a Division of Health Care Service Corporation, a Mutual Legal Reserve Company* Southwest Texas HMO, Inc.* d/b/a HMO BlueÒ Texas * Independent Licensees of the Blue Cross and Blue Shield Association TRANSCRANIAL DOPPLER (TCD) ULTRASOUND MED202.047 BlueReview POSTED DATE: 11/17/2003 EFFECTIVE DATE: 10/24/2003 _____________________________________________________________________________ In some circumstances, it may be necessary to obtain both non-invasive tests before management decisions can be made. ______________________________________________________________________ REFERENCES: · American Academy of Neurology Therapeutics and Technology Assessment Subcommittee. "Assessment: Transcranial Doppler." Neurology 1990; 40:680-81. · Physician Medicare Part B Newsletter # 342, 08/27/93, Non-Invasive Vascular Testing. · BCBSA TEC Assessment Program, "Transcranial Doppler Ultrasound", 1994; Tab 20. · Scientific American Medicine, Chapt.X: "Cerebrovascular Diseases", Feb. 1994, page 1-5. · BCBSA TEC Assessment Program, "MRA of the Head", 1996: Tab. 31 and "MRA of the Neck" 1996; Tab. 32, Medical Policy 6.01.07. · "Transcranial Doppler Ultrasound." American Journal of Neuroradiology, January 1997, 18(1): 127-33. · Annals of Vascular Surgery, January 1997, 11(1): 9-13.Sliwka, U, Lingnau, A, et al. "Prevalence and time course of microembolic signals in patients with acute stroke. A prospective study." Stroke (Feb. 1997) 28(2): 358-63. · Droste, DW, Hagedorn. G, et al. "Bigated transcranial Doppler for the detection of clinically silent circulating emboli in normal persons and patients with prosthetic cardiac valves." Stroke (March 1997), 28(3): 588-92. · Spencer, MP. "Transcranial Doppler monitoring and causes of stroke from carotid endarterectomy." Stroke (April 1997), 28(4): 685-91. · Arnold, M, et al "Continuous intraoperative monitoring of middle cerebral artery blood flow velocities and electroencephalography during carotid endarterectomy. A comparison of the two methods to detect cerebral ischemia." Stroke (July 1997), 28(7): 1345-50. · Scientific American Medicine, IV, Anemia: Hemolysis, (April 1997), page 22. · Adams RJ, McKie VC, Hsu L et al. "Prevention of a first stroke by transfusions in children with sickle cell anemia and abnormal results on Transcranial Doppler Ultrasonography." New England Journal of Medicine (1998); 339:5-11. · Cohen AR. "Sickle cell disease - new treatments, new questions." (Editorial) New England Journal of Medicine (1998); 339:42-44. · Babikian VL, et al. “Transcranial Doppler Ultrasonography.” Journal of Neuroimaging Year 1999 · Alexandrov, Andrei V., et al. “Transcranial Doppler: An Overview of its Clinical Applications.” Journal of Emergency and Intensive Care Medicine (2000) 4(1). Blue Cross and Blue Shield of Texas, a Division of Health Care Service Corporation, a Mutual Legal Reserve Company* Southwest Texas HMO, Inc.* d/b/a HMO BlueÒ Texas * Independent Licensees of the Blue Cross and Blue Shield Association TRANSCRANIAL DOPPLER (TCD) ULTRASOUND MED202.047 BlueReview POSTED DATE: 11/17/2003 EFFECTIVE DATE: 10/24/2003 _____________________________________________________________________________ ______________________________________________________________________ DISCLAIMER: State and federal law, as well as contract language, including definitions and specific inclusions/exclusions, takes precedence over Medical Policy and must be considered first in determining coverage. The member’s contract benefits in effect on the date that services are rendered must be used. Any benefits are subject to the payment of premiums for the date on which services are rendered. Medical technology is constantly evolving, and we reserve the right to review and update Medical Policy periodically. HMO Blue Texas physicians who are contracted/affiliated with a capitated IPA/medical group must contact the IPA/medical group for information regarding HMO claims/reimbursement information and other general polices and procedures. Blue Cross and Blue Shield of Texas, a Division of Health Care Service Corporation, a Mutual Legal Reserve Company* Southwest Texas HMO, Inc.* d/b/a HMO BlueÒ Texas * Independent Licensees of the Blue Cross and Blue Shield Association .