**History/Background and/or General Information**

Non-invasive tests for cerebrovascular arterial function document the nature,
location, extent and severity of disease in extracranial and intracranial
vessels including the carotid and vertebral arteries.

Non-invasive extracranial arterial studies involve the use of direct and
occasionally indirect methods of ultrasound. Please refer to CMS IOM
Publication 100-03, Medicare National Coverage Determinations (NCD) Manual,
Chapter 1, Part 1, Section 20.17 for a definition of direct and indirect
tests.

Doppler ultrasonography is used to evaluate hemodynamic parameters,
specifically the velocity of blood flow and the pattern or characteristics of
flow. The doppler ultrasound involves the evaluation of the supraorbital,
common carotid, external carotid, internal carotid, and the vertebral arteries
in the extracranial cerebrovascular assessment.

The second key component of vascular diagnostic ultrasound is the B-mode, or
brightness-mode image. This real time imaging technique provides a two-
dimensional gray-scale image of the soft tissues and vessels based on the
acoustic properties of the tissues.

Duplex ultrasonography combines the direct visualization capabilities of
B-mode ultrasonography and the blood-flow velocity measurements of doppler
ultrasonography.

**Definitions:**

  * A physiologic study implies functional measurement procedures including Doppler ultrasound studies, blood pressure measurements, transcutaneous oxygen tension measurements or plethysmography. A complete study includes pressure measurements and an additional physiologic technique (eg, Doppler waveforms or plethysmography).
  * Plethysmography implies volume measurement procedures including air, impedance, or strain gauge methods.
  * A duplex scan implies an ultrasonic scanning procedure with display of both two-dimensional structure and motion with time and Doppler ultrasonic signal documentation with spectral analysis and/or color flow velocity mapping or imaging.

**Covered Indications**

Non-invasive extracranial arterial studies will be considered medically
reasonable and necessary under the following circumstances:

  * To initially evaluate a patient presenting with an asymptomatic carotid bruit identified on physical examination. However, repeatedly using this test for a patient with an asymptomatic carotid bruit with no evidence of carotid stenosis is routine monitoring. As such, it is considered screening and is noncovered.
  * To evaluate a symptomatic patient with a carotid bruit(s).
  * To monitor a patient with known carotid stenosis. Patients demonstrating a diameter reduction of 30-50% are normally followed on an annual basis, whereas patients with a diameter reduction of greater than 50% are normally followed every six months. It is not necessary to monitor patients with a diameter reduction of less than 30%.
  * To initially evaluate a patient who has had a recent stroke (recent is defined as less than six months) to determine the cause of the stroke.
  * To evaluate a patient with focal cerebral or ocular transient ischemic symptoms (including, but not limited to, localizing symptoms, weakness of one side of the face, slurred speech, weakness of limb, ocular microembolism, arterial occlusions on retinal examination (branch or central), ischemic optic neuropathy, suspected dural or carotid cavernous fistulae). Ocular transient ischemic attacks are defined as retinal or visual field deficits and not temporarily blurred vision.
  * To evaluate a patient with syncope that is strongly suggestive of vertebrobasilar or bilateral carotid artery disease in etiology, as suggested by medical history.
  * To evaluate a patient with retinal arterial emboli (Hollenhorst plaques)
  * To evaluate a patient with transient monocular blindness (amaurosis fugax).
  * To evaluate a patient with signs/symptoms of subclavian steal syndrome. The symptoms usually associated with subclavian steal syndrome are a bruit in the supraclavicular fossa, unequal radial pulses, arm claudication following minimal exercise, and a difference of 20mmHg or more between the systolic blood pressures in the arms.
  * To evaluate a patient with proven carotid disease on medical management in whom cerebrovascular symptoms become recurrent.
  * To evaluate a patient presenting with an injury to the carotid artery or blunt neck trauma.
  * To evaluate a patient with vasculitis involving the extracranial carotid arteries.
  * To evaluate a patient with a suspected aneurysm of the carotid artery. This is suspected in patients with swelling of the neck particularly if occurring post carotid endarterectomy.
  * To evaluate a patient with suspected dissection.
  * To evaluate pulsatile neck masses.
  * To monitor patients who are post carotid endarterectomy. These patients are normally followed with duplex ultrasonography on the affected side at 6 weeks, 6 months, 1 year, and annually thereafter. 
  * To preoperatively validate the degree of carotid stenosis of a patient whose previous duplex scan revealed a greater than 70% diameter reduction. The duplex is only covered when the surgeon questions the validity of the previous study and the repeat test is being performed in lieu of a carotid arteriogram.
  * Preoperative evaluation of patients scheduled for major cardiovascular surgical procedures when there is evidence of systemic atherosclerosis.

Non-invasive vascular studies are medically necessary only if the outcome will
potentially impact the clinical management of the patient. Services are deemed
medically necessary when all of the following conditions are met:

1) Significant signs/symptoms of ischemia are present;

2) The information is necessary for appropriate medical and/or surgical
management; and

3) The test is not redundant of other diagnostic procedures that must be
performed.

**Limitations**

  * Dizziness is not a typical indication unless associated with other localizing signs or symptoms. However, episodic dizziness with symptom characteristics typical of transient ischemic attacks may indicate medical necessity, especially when other more common sources (eg, postural hypotension, arrhythmia or transiently decreased cardiac output as demonstrated by cardiac events monitoring) have been previously excluded. 
  * When reporting syncope as an indication for this service, it is necessary to document that other, more common causes have been ruled out.
  * When an uninterpretable study results in performing another type of study, only the successful study should be billed.
  * Non-invasive studies are reasonable and necessary only if the outcome will potentially impact the clinical course of the patient. For example, the studies are unnecessary when the patient is (or is not) proceeding on to other diagnostic and/or therapeutic procedures regardless of the outcome of the non-invasive studies. If it is obvious from the findings of the history and physical examination that the patient is going to proceed to angiography, then non-invasive vascular studies are not medically necessary. 
  * Performance of both non-invasive extracranial arterial studies and non-invasive evaluation of extremity veins during the same encounter is not appropriate as a general practice or standing protocol, and therefore, would not generally be expected (American College of Radiology, 2010). Consequently, documentation must clearly support the medical necessity if both procedures are performed during the same encounter, and be available upon request.

When reporting syncope as an indication for this service, it is necessary to
document that other, more common causes have been ruled out.

Generally, it is not expected that these services would be performed more than
once in a year, excluding inpatient hospital and emergency room places of
service.

**Methods Not Acceptable For Reimbursement:**

  * Pulse delay oculoplethysmography
  * Carotid phonoangiography and other forms of bruit analysis are covered services, but are included in the reimbursement for the office visit
  * Periorbital photoplethysmography
  *  Thermography
  * Light reflection rheography
  * Please refer to CMS IOM Publication 100-03, _Medicare National Coverage Determinations (NCD) Manual_ , Chapter 1, Part 1, Section 20.14 for additional plethysmography noncovered procedures.

The use of a simple hand-held or other Doppler device that does not produce
hard copy output, or that produces a record that does not permit analysis of
bidirectional vascular flow, is considered part of the physical examination of
the vascular system and is not separately reported (CPT 2010). The appropriate
assignment of a specific ultrasound CPT code is not solely determined by the
weight, size, or portability of the equipment, but rather by the extent,
quality, and documentation of the procedure. If an examination is performed
with hand-carried equipment, the quality of the exam, printout, and report
must be in keeping with accepted national standards. Since, the standard for
the above indications is a color-duplex scan, portable equipment must be able
to produce combined anatomic and spectral flow measurements.

As published in the CMS IOM Publication 100-08, _Medicare Program Integrity
Manual_ , Chapter 13, Section 13.5.4, an item or service may be covered by a
contractor LCD if it is reasonable and necessary under the Social Security Act
Section 1862 (a)(1)(A). Contractors shall determine and describe the
circumstances under which the item or service is considered reasonable and
necessary.

**Provider Qualifications**

The accuracy of non-invasive vascular diagnostic studies depends on the
knowledge, skill and experience of the technologist and the physician
performing the interpretation of the study. Consequently, the technologist and
the physician must maintain proof of training and experience.

All non-invasive vascular diagnostic studies must be: (1) performed by a
qualified physician, or (2) performed under the general supervision of a
qualified physician by a technologist who has demonstrated minimum entry level
competency by being credentialed in vascular technology, and/or (3) performed
in a laboratory accredited in vascular technology.

A qualified physician for this service is defined as follows: 1) A physician
who has staff privileges to interpret vascular laboratory studies in a
hospital that participates in the Medicare program in the state of Florida and
the U.S. territories of Puerto Rico and the U.S. Virgin Islands (as
applicable) or; 2) A physician who works in a certified vascular laboratory
or; 3) A physician who has the RVT or the RPVI (Registered Physician in
Vascular interpretation - provided by the ARDMS) certificate or ASN:
Neuroimaging Subspecialty Certification; 4) Physicians who are not covered by
one of these criteria will have until 2008 to comply.

Examples of certification in vascular technology for non-physician personnel
include:

  * Registered Vascular Technologist (RVT) credential
  * Registered Vascular Specialist (RVS) credential
  * Registered Technologist in Vascular Sonography (R.T. (VS))

These credentials must be provided by nationally recognized credentialing
organizations such as:

  * The American Registry of Diagnostic Medical Sonographers (ARDMS) which provides Registered Diagnostic Medical Sonographer (RDMS) and Registered Vascular Technologist (RVT) RVT credentials
  * The Cardiovascular Credentialing International (CCI) which provides RVS credential
  * The American Registry of Radiologic Technologists (ARRT) which provides vascular sonography (VS) credential.

Appropriate nationally recognized laboratory accreditation bodies include:

  * Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL)
  * American College of Radiology (ACR)

However, if the facility has a documented process for grand-fathering
experienced technicians who have performed the services referenced in this LCD
(a process addressing years of service and experience with number of
supervised cases), this documentation should be available upon request;
otherwise the provider must have documentation available upon request which
indicates that the technician meets the credentialing requirements as stated
above or is in the process of obtaining this credentialing.

For guidelines regarding general supervision during performance of a
procedure, please refer to 42 CFR Section 410.32 Diagnostic x-ray tests,
diagnostic laboratory tests, and other diagnostic tests: Conditions.