This is not the document you are looking for? Use the search form below to find more!

Report home > Health & Fitness

Transcranial Doppler (TCD) Ultrasonography

0.00 (0 votes)
Document Description
Transcranial Doppler (TCD) ultrasonography is considered medically necessary when ANY of the following indications are met: • screening of children age 2-16 years with sickle cell disease for assessing stroke risk • detection and monitoring of angiographic vasospasm (VSP) after spontaneous subarachnoid hemorrhage (sSaH) • detection of abnormal cerebral blood flow and/or embolic events during carotid endarterectomy (CEA) as well as in the immediate postoperative period
File Details
  • Added: April, 29th 2011
  • Reads: 837
  • Downloads: 19
  • File size: 209.86kb
  • Pages: 14
  • Tags: transcranial doppler, tcd, ultrasonography, brain, guidelines
  • content preview
Submitter
  • Name: rosie
Embed Code:

Add New Comment




Related Documents

Transvaginal ultrasonography associated with colour Doppler energy in the diagnosis of hydrosalpinx

by: bailey, 5 pages

The aims of this prospective study were to investigate the accuracy of B-modetransvaginal ultrasonography alone, using the typical finding of the presence of an elongated shaped mass with incomplete ...

Three-dimensional Ultrasonography and Power Doppler in Ovarian Cancer Screening of Asymptomatic Peri-and Postmenopausal Women

by: najmah, 8 pages

To determine whether introducing three-dimensional (3D) ultrasonography with power Doppler facilities as a secondary screening test, preceded by annual transvaginal grayscale ultrasonography (TVUS) ...

How useful is uterine artery Doppler ultrasonography in predicting pre-eclampsia and intrauterine growth restriction?

by: ashton, 3 pages

Pre-eclampsia and intrauterine growth restriction remain important causes of maternal and neonatal complications and death.1-3These 2 conditions are felt to be the result of abnormal placenta ...

Ultrasonography of the kidney and the renal vessels Part I: Normal findings, inherited and renoparenchymatous diseases

by: tetsuo, 30 pages

Renal ultrasonography has become the standard imaging modality in the investigation of kidneys because it offers excellent anatomic detail, requires no special preparation of patients is readily ...

Acetylsalicylic Acid for the Prevention of Preeclampsia and Intra-uterine Growth Restriction in Women with Abnormal Uterine Artery Doppler: A Systematic Review and Meta-analysis

by: kinga, 9 pages

Preeclampsia is a major global cause of maternal, neonatal and perinatal mortality. From studies of placental pathophysiology in women with preeclampsia, a potentially important role of low-dose ...

Ultrasonography in Developmental Dysplasia of the Hip

by: rebeka, 16 pages

A safe, noninvasive method of imaging of the hip: it can be used both for diagnosis and to monitor treatment. Provides advantages when combined with clinical examination: it can provide information ...

A systematic review of ultrasonography in osteoarthritis

by: chisami, 10 pages

Ultrasonography has been increasingly utilized to aid the understanding and management of rheumatic conditions. In recent years there has been a focus on the validity and utility of ultrasonography ...

Ultrasonography In Orthopaedic Practice - A Review

by: hulyah, 5 pages

Ultrasonography is an invaluable non-invasive imaging technique that uses non-ionizing high frequency sound energy of 1 - 10 mHz in the diagnosis and management of a variety of disorders. There is ...

Postoperative spinal ultrasonography findings in spinal dysraphia

by: katja, 3 pages

Diastematomyelia is a form of spinal dysraphism involving sagittal clefting of the spinal cord, conus medullaris, and/or filum terminale into two hemicords. It can be an isolated finding or can be ...

Ultrasonography and computed tomography in patients with right lower quadrant pain: Difficult cases of appendicitis

by: roberto, 8 pages

Acute appendicitis is a common cause of acute abdomen and both computed tomography (CT) and ultrasonography (US) are used in the diagnostic work-up of these patients. In general, imaging has high ...

Content Preview
MEDICAL NECESSITY GUIDELINES


Subject: Transcranial Doppler (TCD)

Effective Date: 11/15/2006
Ultrasonography
Revision Date: 11/15/2007
Number: 0345



INSTRUCTIONS FOR USE
This Medical Necessity Guideline outlines the factors CareAllies considers in determining medical necessity for this indication.
Please note, the terms of a participant’s particular benefit plan document or summary plan description (SPD) may differ significantly
from the standard upon which this Medical Necessity Guideline is based. For example, a participant’s benefit plan document or SPD
may contain a specific exclusion related to the topic addressed. In the event of a conflict, a participant’s benefit plan document or
SPD always supercedes the information in this Medical Necessity Guideline. In the absence of a controlling federal or state
coverage mandate, benefits are ultimately determined by the terms of the applicable benefit plan document or SPD. Coverage
determinations in each specific instance require consideration of 1) the terms of the applicable group benefit plan document or SPD
in effect on the date of service; 2) any applicable laws/regulations, and; 3) the specific facts of the particular situation. Medical
Necessity Guidelines are not recommendations for treatment and should never be used as treatment guidelines. ©2007
Intracorp/CareAllies


Transcranial Doppler (TCD) ultrasonography is considered medically necessary when ANY of the
following indications are met:


• screening of children age 2–16 years with sickle cell disease for assessing stroke risk
• detection and monitoring of angiographic vasospasm (VSP) after spontaneous subarachnoid
hemorrhage (sSaH)
• detection of abnormal cerebral blood flow and/or embolic events during carotid endarterectomy
(CEA) as well as in the immediate postoperative period

TCD ultrasonography for the following conditions is considered experimental, investigational or
unproven and not medically necessary (this list may not be all-inclusive):


• cerebral microembolism detection, for the detection of cerebral microembolic signals in a variety
of cardiovascular/cerebrovascular disorders/procedures
• coronary artery bypass graft (CABG) surgery, during CABG for detection of cerebral microemboli
and to document changes in flow velocities and carbon dioxide (CO2) reactivity during CABG
surgery
• vasomotor reactivity (VMR) testing (i.e., vasoreactive study), for the detection of impaired
cerebral hemodynamics in patients with severe (>70%) asymptomatic extracranial internal carotid
artery (ICA) stenosis, symptomatic or asymptomatic extracranial ICA occlusion, and cerebral
small-artery disease


General Background

The brain is dependent on a constant supply of blood to maintain normal function and structure because
of its high metabolic rate and inability to store glucose or oxygen. Therefore, cerebral blood flow must be
regulated to ensure the continuous delivery of these nutrients. Measurement of cerebral blood flow can
be used to assess flow deficits and to guide therapeutic interventions directed at optimizing cerebral
blood flow (Kirkness, 2005).

Diagnostic ultrasonography is an established, effective diagnostic imaging technique that uses high-
frequency ultrasound waves for both imaging and Doppler examinations. There are many applications of
diagnostic ultrasound (American College of Radiology [ACR], 2006b). Ultrasonography uses a variety of
transducers which are available for different applications. Ultrasonography can be coupled with Doppler
Page 1 of 14
Number: 0345


devices, with or without color, allowing for flow measurements in vascular structures (Koenigsberg, et al.,
2003). Echoencephalography is a type of diagnostic ultrasound that can be used on neonates for
determination of ventricular size, delineation of cerebral contents, and detection of fluid masses or other
intracranial abnormalities.

There are four types of Doppler ultrasound, including (Nissl, 2007):

Continuous Wave Doppler: This measures how continuous sound waves change in pitch as
they encounter blood flow blockages or narrowed blood vessels.
Duplex Doppler: This produces a picture of a blood vessel and the organs that surround it. A
computer converts the Doppler sounds into a graph that provides information about the speed
and direction of blood flow through the blood vessel being examined.
Color Doppler: In this procedure, a computer converts the Doppler sounds into colors that are
overlaid on the image of a blood vessel. The colors represent the speed and direction of flow
through the vessel.
Power Doppler: This is a newer technique that is up to five times more sensitive than color
Doppler. Power Doppler can get pictures that are difficult or impossible from standard color
Doppler. Power Doppler is most commonly used to evaluate blood flow through vessels within
solid organs.

Transcranial Doppler (TCD) ultrasonography is a noninvasive ultrasonic technique that uses a hand-held
low-frequency (i.e., 2–2.5 megahertz [MHz]) sector transducer that sends fixed or pulsed sound waves to
measure the velocity of blood flowing in the basal arteries of the brain. Sound waves are transmitted
through temporal, orbital, and suboccipital acoustic windows of the skull. When the sound waves come in
contact with blood, they are reflected off the red blood cells through the brain and skull to a detector. The
velocity of the sound waves reflected to the surface is changed because the blood cells themselves are in
motion toward, or away, from the sound wave detector. This is called Doppler shift and is directly related
to the velocity and flow of the blood cells. The velocity of the blood cells is faster during systole and
slower during diastole. The blood in the center of the lumen moves quicker than the blood near the vessel
wall. A spectrum of flow velocities is produced. TCD measurements of flow velocity are commonly made
in the middle cerebral artery. Other arteries that may be measured by TCD include the anterior cerebral,
anterior communicating, posterior cerebral and communicating, and basilar arteries (Chernecky, et al.,
2008; Mahla, et al., 2005).

TCD is used primarily to evaluate and manage patients with cerebrovascular disease. Conventional and
digital subtraction angiography (DSA) constitute the reference standard for evaluating patency and
degree of stenosis in intracranial vessels. TCD is operator-dependent and requires training and
experience to perform and interpret results. Diagnostic ultrasound examinations should be supervised
and interpreted by trained and qualified physicians (ACR, 2006b). TCD can be performed by
sonographers, technologists, and physicians. Interpretation of TCD measurements is performed by
neurologists and other specialists (Sloan, et al., 2004).

An advantage of TCD is that it can be performed at the bedside and repeated as needed or applied for
continuous monitoring. A limitation to TCD is that it can only record cerebral blood flow velocities in
certain segments of large intranial vessels, although large vessel intracranial arterial disease commonly
occurs at these locations (Sloan, et al., 2004). Factors that may affect TCD results include (Chernecky, et
al., 2008):

• the body habitus of the patient and the technical condition of the equipment
• flow velocity is age-dependent and decreases continuously through adulthood
• detection of small aneurysms is limited by insonation angles and spatial resolution
• intramural calcification may inhibit sound penetration, leading to false-positive results
• accurate transmission and reflection of ultrasonographic signals can be affected by the presence
of calcium or gas overlying the vessel
• intracranial pressure, blood pressure and volume, hematocrit, and subarachnoid hemorrhage
affect flow velocity
Page 2 of 14
Number: 0345


• false-negative exams of vasospasm are associated with chronic high blood pressure, increased
intracranial pressure, severe spasm of the carotid siphon, and distal vasospasm
• tobacco and caffeine use
• false-positive and false-negative results have been reported when evaluating for cross flow
through the anterior and posterior communicating arteries in patients with occlusive
cerebrovascular disease

There are many proposed applications for TCD including, but not limited to, the following (Chernecky and
Berger, 2008; American Academy of Neurology [AAN], 2004):

• predict the risk of stroke in children with sickle cell anemia
• vasoconstriction as a result of insult
• cerebral dynamics after head injury
• intraoperatively to monitor velocity in the middle portion of the cerebral artery during carotid
endarterectomy (CEA)
• evaluate collateral circulation stenosis
• establish brain death in adults
• diagnostic in intracranial aneurysms, arteriovenous malformations, and moyamoya syndrome
• assessment of blood supply in intracranial neoplasms
• cerebral microembolism detection, for the detection of cerebral microembolic signals in a variety
of cardiovascular/cerebrovascular disorders/procedures
• coronary artery bypass graft (CABG) surgery, during CABG for detection of cerebral microemboli
and to document changes in flow velocities and carbon dioxide (CO2) reactivity during CABG
surgery
• vasomotor reactivity (VMR) testing (i.e., vasoreactive study), for the detection of impaired
cerebral hemodynamics in patients with severe (>70%) asymptomatic extracranial ICA stenosis,
symptomatic or asymptomatic extracranial ICA occlusion, and cerebral small-artery disease

U.S. Food and Drug Administration (FDA)
The FDA regulates TCD systems as Class II devices, and the commonly used systems have been
approved via the FDA 510(k) process.

Literature Review
Sickle Cell Disease: Sickle cell disease is an autosomal recessive disorder associated with thrombotic
occlusions of the large intracranial arteries which may lead to a stroke in young adults (Sila, et al., 2007).
These arteries are accessible to TCD, and TCD can be used to monitor flow velocity over time. Mean flow
volumes of ≥ 200 cm per second are considered abnormal and require transfusion (Kassab, et al., 2007).

A randomized, controlled, multicenter study was titled the “Stroke Prevention Trial in Sickle-Cell Anemia,”
or STOP (Adams, et al., 1998). To enter the study, children with sickle-cell anemia and no history of
stroke had to have undergone two TCD studies that showed that the time-averaged mean blood flow
velocity in the internal carotid or middle cerebral artery was 200 cm per second or higher. The patients
were randomly assigned to receive standard care or transfusions to reduce the hemoglobin S
concentration to less than 30% of the total hemoglobin concentration. The incidence of stroke (cerebral
infarction or intracranial hemorrhage) was compared between the two groups. A total of 130 children were
enrolled; 63 were randomly assigned to receive transfusions and 67 to receive standard care. There were
10 cerebral infarctions and one intracerebral hematoma in the standard-care group, as compared to one
infarction in the transfusion group—a 92% difference in the risk of stroke. The investigators and the
National Heart Lung and Blood Institute (NHLBI), which funded the study, decided to terminate it. A
clinical alert based on STOP was issued to physicians in the United States; it noted that STOP reduced
first-time stroke in children with sickle-cell anemia by 70% by the administration of prophylactic
transfusion therapy. The study design was based on the clinical observation that, if hemoglobin S (HbS)
levels are maintained at or below 30% in children who have had a stroke, the incidence of recurrence can
be reduced from 80% to approximately 10% with periodic exchange or simple transfusions.

In a follow-up study of the STOP trial, Lee et al. (2006) confirmed the reliability of TCD in identifying
children with sickle-cell disease at high risk for stroke and the efficacy of transfusion in reducing risk of
Page 3 of 14
Number: 0345


stroke. Six stroke events in the post-trial follow-up were predicted by abnormal TCD results, regardless of
the treatment status. None of the patients with normal and conditional TCD results on follow-up
developed stroke.

Intracranial Vasospasm after Subarachnoid Hemorrhage (SAH): Intracranial vasospasm is the
constriction of cerebral blood vessels due to the presence of blood in the subarachnoid space after a
rupture of cerebral aneurysm or trauma. The vasospasm may result in ischemia to the brain. The
subarachnoid hemorrhage (SAH) can be identified by TCD up to 1–2 days before it becomes clinically
symptomatic, allowing for initiation of triple H therapy (i.e., (hypervolemia, hypertension, and
hemodilution). A mean flow volume of 120 cm per second is a sign of mild spasm. A value above 180 cm
per second is a sign of severe spasm (Kassab, et al., 2007).

Post-traumatic cerebral vasospasms occur in the late phase following trauma (i.e., 4–5 days). An
approximate 30% incidence rate was reported using TCD versus a 19% incidence rate when cerebral
angiography was used for detection (Trinidad, et al., 2008).

Textbook literature states the detection and monitoring of post-SAH vasospasm remains the most
common use of TCD (Bedell, et al., 2008). Professional society practice guidelines state TCD is able to
provide information, and the clinical utility has been established in the detection and monitoring of
angiographic vasospasm after spontaneous subarachnoid hemorrhage (sSaH) (AAN, 2004).

Carotid Endarterectomy (CEA): Textbook literature by Mahla et al. (2005) states that, due to increasing
experience with TCD during CEA, it has become one of the accepted methods for monitoring cerebral
blood flow during carotid surgery, especially with detection of emboli. Preoperative TCD screening may
be useful in defining which asymptomatic patients are at higher risk for stroke. Surgeons who use TCD
monitoring have been able to alter their technique to reduce intraoperative microembolization. The
authors state that TCD is becoming increasingly accepted as useful for the detection of emboli after
completion of arterial repair. There are studies that demonstrate the utility of TCD in detecting an
abnormally high rate of postoperative embolization after carotid surgery.

TCD monitoring of the middle cerebral artery during the successive stages of CEA was used to assess
the association of cerebral microembolism and hemodynamic changes with stroke and stroke-related
death (Ackerstaff, et al., 2000). In this multicenter study of 1058 patients, researchers observed 31
patients with ischemic and eight patients with hemorrhagic operative strokes. Four of these patients died.
The authors stated, “in CEA, TCD-detected microemboli during dissection and wound closure, ≥ 90%
middle cerebral artery velocity decrease at cross-clamping, and ≥ 100% pulsatility index increase at
clamp release are associated with operative stroke.” In combination with the presence of preoperative
cerebral symptoms and ≥ 70% ipsilateral internal carotid artery (ICA) stenosis, four TCD monitoring
variables (age, sex, preoperative cerebral symptoms, and ipsilateral and contralateral ICA stenosis
reasonably discriminate between patients with and without operative stroke. The researchers conclude
that this supports the use of TCD as a potential intraoperative monitoring modality to alter the surgical
technique in order to decrease the risk of stroke during or immediately after the operation.

Ogasawara et al. (2005) studied whether intraoperative blood flow velocity monitoring in the middle
cerebral artery by using TCD could be used as a reliable technique to detect cerebral hyperperfusion
following CEA by comparing findings with those of brain single photo emission computed tomography
(CT) (SPECT). Intraoperative blood flow velocity monitoring was achieved in 60 of 67 patients undergoing
CEA for the treatment of ipsilateral ICA stenosis ≥ 70%. SPECT was used to assess cerebral blood flow
before and immediately after CEA. Of the 60 patients, six patients experienced post-CEA hyperperfusion.
The sensitivity, specificity, and positive predictive value (PPV) of the blood flow volume increases
immediately after declamping of the ICA for detecting post-CEA hyperperfusion were 100%, 94%, and
67%, respectively. The sensitivity and specificity of the blood flow volume increases at the end of the
procedure for detecting post-CEA hyperperfusion were 100% for both parameters. Hyperperfusion
syndrome developed in two patients with post-CEA hyperperfusion. In two patients, blood flow volume
monitoring was not possible because of failure to obtain an adequate bone window. The authors
concluded that “intraoperative middle cerebral artery blood flow volume monitoring by using TCD is a less
reliable method to detect cerebral hyperperfusion following CEA than postoperative middle cerebral artery
blood flow monitoring, provided adequate monitoring can be achieved” (Ogasawara, et al., 2005).
Page 4 of 14
Number: 0345



Coronary Artery Bypass Graft (CABG) Surgery:
Textbook literature by Mahla et al. (2005) states that
TCD is used during CABG to detect air or particulate emboli during cannulation or bypass, when weaning
from bypass, and during decannulation, but outcome data proving utility is still lacking. Professional
society practice guidelines state that TCD is probably useful during CABG for detection of cerebral
microemboli and to document changes in flow velocities and CO2 reactivity during CABG surgery. Data
are insufficient regarding the clinical impact of this information (AAN, 2004).

Rodriquez et al. (2006) investigated the effect of choosing different intensity thresholds on the sensitivity
and specificity of detecting cerebral emboli. Eight patients had TCD recordings analyzed during
cardiopulmonary bypass. The authors concluded that using intensity thresholds higher than the optimal
for embolus detection decreases high-intensity transient signals. The authors also stated that choosing a
threshold depends on the type of method used for measuring the signal intensity. Furthermore, uniform
threshold criteria and comparative studies between Doppler devices are needed for making clinical trials
more comparable.

Monitoring for Heart Shunts: It has been reported that TCD can detect the presence of right to left
shunts such as patent foramen ovale in patients with contraindications to transesophageal
echocardiography (TEE) with similar sensitivity and specificity (Kassab, et al, 2007). The appearance of
echogenic bubbles greater than 25 in the left atrium, after injection of agitated saline and the Valsalva
maneuver, is diagnostic of patent foramen ovale. TCD may detect these emboli in the middle cerebral or
carotid arteries (Yatsu, 2005).

Souteyrand et al. (2006) compared transthoracic echocardiography (TTE) using second harmonic
imaging, TCD, and a TEE to determine which is most accurate and reliable for the detection of patent
foramen ovale. TEE is considered the gold standard to find a defect of the interatrial septum. From
August 2003 to April 2004, 107 patients who were hospitalized for stroke or transient ischemic attack
underwent TTE, TCD, and TEE. A patent foramen ovale was found in 41%, or 44 patients who had TTE
and TEE. All contrast tests were positive with TCD for the 44 patients. The contrast test was positive only
with TTE and TCD for two patients. Four false- negative contrast tests were found with TTE. Of the 63
patients who had a negative contrast test with TEE and TTE, the results were the same with TCD for 59
of the patients. The use of TCD was limited in older patients, since sometimes the temporal window is
calcified, therefore preventing the use of TCD. The authors stated they were not able to find the cause for
the four positive tests. The authors concluded their study confirms that TEE has limitations in the
diagnosis of patent foramen ovale. The limitations may be due to sedation, which hinders the Valsalva
maneuver. The authors concluded that TCD has an excellent negative predictive value (NPV) at 100%.
Therefore, the authors stated TCD used with TTE can accurately and reliably detect cases of patent
foramen ovale.

Intracranial Steno-occlusive Disease: Vascular imaging can be divided into noninvasive and invasive
studies. Commonly used noninvasive tests are Duplex scans (i.e., B-mode and Doppler combined), TCD,
magnetic resonance angiography (MRA), and computed tomography angiography (CTA). Duplex scans
show an accurate image of the extracranial carotid and vertebral arteries. TCD is useful for the evaluation
of the intracranial cerebral arteries by measuring flow velocities and directions. MRA and CTA are useful
for the evaluation of intracranial and extracranial large arteries. Combined use of these noninvasive tests
is usually adequate for evaluation of most stroke patients (Chung, et al., 2003).

The Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial was a prospective,
multicenter study. The aim of this study was to validate the ability of TCD and MRA to diagnose 50–90%
intracranial stenosis of the large proximal arteries compared to catheter angiography. SONIA was a
companion study to the WASID trial (Warfarin Aspirin Symptomatic Intracranial Disease). SONIA enrolled
407 patients at 46 sites in the United States. For prospectively tested noninvasive test cutpoints, PPVs
and NPVs were TCD, PPV 36% (95% confidence interval (CI): 27–46); NPV, 86% (95% CI: 81–89); MRA,
PPV 59% (95% CI: 54–65); NPV, 91% (95% CI: 89–93). For cutpoints modified to maximize PPV, they
were TCD, PPV 50% (95% CI: 36–64), NPV 85% (95% CI: 81–88); MRA PPV 66% (95% CI: 58–73),
NPV 87% (95% CI: 85–89). The authors concluded that “both TCD and MRA noninvasively identify 50–
99% intracranial large vessel stenoses with substantial NPV. The SONIA trial methods allow TCD and
Page 5 of 14
Number: 0345


MRA to reliably exclude the presence of intracranial stenosis. Abnormal findings on TCD or MRA require
a confirmatory test such as angiography to reliably identify stenosis” (Feldman, et al., 2007).

Tsivgoulis et al. (2007) evaluated the diagnostic accuracy of TCD against CTA in patients with acute
cerebral ischemia. Consecutive patients presenting to the emergency department with symptoms of acute
(< 24 hours) cerebral ischemia underwent emergent high-resolution brain CTA with a multidetector helical
scanner. TCD was performed at bedside with a standardized, fast-track insonation protocol before or
shortly (< two hours) after completion of the CTA. Previously published diagnostic criteria were
prospectively applied for TCD interpretation independent of angiographic findings. A total of 132 patients
underwent emergent neurovascular assessment with brain CTA and TCD. Compared to CTA, TCD
showed 34 true-positive, nine false-negative, five false-positive, and 84 true-negative studies (sensitivity
79.1%, specificity 94.3%, PPV 87.2%, NPV 90.3%, and accuracy 89.4%). In nine cases (7%), TCD
showed findings complementary to the CTA (i.e., real-time embolization, collateralization of flow with
extracranial ICA disease, alternating flow signals indicative of steal phenomenon). The authors concluded
that “bedside TCD examination yields satisfactory agreement with urgent brain CTA in the evaluation of
patients with acute cerebral ischemia. TCD can provide real-time flow findings that are complementary to
information provided by CTA” (Tsivgoulis, et al., 2007).

Forty-three patients were referred for TCD and underwent contrast angiography or MRA to determine the
accuracy of TCD in detecting intracranial stenoses and occlusions (Navarro, et al., 2004). Results
showed 21 patients with normal TCD and 22 who were diagnosed with terminal internal carotid artery
(TICA) stenosis or occlusion on TCD. Four patients had abnormal TCD findings that were not confirmed
by angiography. Two of 21 patients with normal TCD showed moderate (<50%) stenosis of the TICA and
cavernous segment of the ICA at angiography. TCD sensitivity was 90%, and specificity was 83%. The
authors concluded that TCD is a sensitive screening tool for lesions in the TICA. Specificity is likely
affected by the wide spectrum of stenosis severity shown at angiography and time lags between the
studies.

Felberg et al. (2002) prospectively compared the accuracy of TCD criteria and mean flow velocity (MFV)
thresholds to magnetic resonance imaging, computed tomography, and DSA in 136 patients with
symptoms of recent or remote stroke or transient ischemic attack. TCD showed 31 true-positive, nine
false-positive, two false-negative, and 94 true-negative studies. For all vessels, TCD had a sensitivity of
93.9% and a specificity of 91.2%. The authors concluded that TCD is both sensitive and specific in
identifying ≥ 50% intracranial arterial stenosis.

Navarro et al. (2007) systematically reviewed the literature addressing the accuracy of TCD compared to
angiography for the diagnosis of ≥ 50% middle cerebral artery stenosis in patients with transient ischemic
attack or ischemic stroke. Six studies met their inclusion criteria. Using laboratory-specific variable mean
flow velocity cutoffs, self-reported best accuracy results yield a mean weighted average sensitivity of
92%, specificity of 92%, PPV of 88% and NPV of 98% for 80 cm/s cutoff. For 100 cm/s cutoff, the
sensitivities were 100%, specificity 97%, PPV 88% and NPV 100%. The authors concluded that “although
limited to few reports, this analysis demonstrates fair TCD performance against angiography. Since
increasing velocity cutoffs do not yield decreasing sensitivity and increasing specificity, further studies are
required to determine optimal velocity values and possibly other criteria such as velocity ratios to develop
a screening test with balanced performance parameters” (Navarro, et al., 2007).

Brain Death: Brain death is primarily diagnosed by the absence of any clinical sign of brain stem activity
and can be confirmed on the electroencephalogram (EEG). Angiography or radionuclear cerebral flow
studies can be used to support the diagnosis of brain death. However, angiography is an invasive
technique and requires transport of a critically ill patient. TCD is a noninvasive technique which can be
performed at the bedside. TCD has been used as an aid to the diagnosis of brain death. TCD studies can
be used to determine whether definitive studies documenting brain death need to be performed. Further
studies that document the sensitivity and specificity of TCD in the diagnosis of brain death are needed
before it can be used as a sole criterion for brain death (Mahla, et al., 2005).

The validity of TCD to confirm brain death by comparing it to angiography was studied by Poularas et al.
(2006). Both angiography and TCD confirmed brain death in all patients (n=40). Five patients required
repeated TCD examinations because of initial detection of a diastolic to and fro flow pattern. The authors
Page 6 of 14
Number: 0345


concluded that TCD was a sensitive tool to diagnose brain death, affording a reliable alternative
examination to standard angiography.

The frequency and causes of false-negative results in TCD examination for brain death were assessed in
a study by de Frietas et al. (2006). The two causes of false-negative TCD results in brain-dead patients
include both a lack of signal and the persistence of flow in the intracranial arteries. A total of 270 patients
were included in the study. The authors examined patients who were potential organ donors. The first
TCD examination gave a pattern of flow arrest in at least two intracranial arteries, confirming the
diagnosis of cerebral circulatory arrest in 204 (75.5%) of the patients. In nine (17%) brain-dead patients
without cerebral circulatory arrest, a lack of signal was observed in TCD examination. In seven (13.7%)
brain-dead patients without cerebral circulatory arrest, persistent flow was observed in the intracranial
arteries. In 10 (3.7%) of the brain-dead patients, there was a possible persistence of intracranial flow. The
authors also reported on the results of 16 studies which included a total of 680 patients. The overall
sensitivity of TCD for confirming brain death was 88%, and the cause of false-negative results was a lack
of signal in 7% of the patients and persistence of flow in 5%. The overall specificity was 98%. The authors
concluded that uniform criteria are needed for the use of TCD as a confirmatory test for brain death.

Monteiro et al. (2006) assessed the validity of TCD in confirming brain death. A systematic review of the
literature published between 1980 and 2004 was performed. The authors found two high-quality and eight
low-quality studies with a total of 684 patients. The high-quality studies showed a sensitivity of 95% and a
specificity of 99% to detect brain death. Meta-analysis of all ten studies showed a sensitivity of 89% and a
specificity of 99%. The authors concluded that cerebral circulatory arrest in the anterior and posterior
circulation predicted fatal brain damage in all patients; therefore, TCD can be used to determine the
appropriate time for angiography.

Children: Hirsch et al. (2002) reported on the use of TCD examinations in children (i.e., mean age 12.7
years; range in age 0.5–18 years) without an open fontanelle. The study was over seven years. A total of
858 children were referred from an outpatient clinic. The patients were divided into three groups
according to the reason for referral. Positive pathological results were found in the following: headache
and orthostatic dysregulation (0.4%), acute neurological symptoms (5.4%), and other indications (22.2%).
The PPV of finding an abnormality was very low at 0.5%. The authors concluded that TCD examination is
ineffective in children with nonspecific headache or orthostatic dysregulation. The authors found a higher
percentage of abnormal results in children referred for other indications. Those children usually undergo
MRI or MRA, if necessary. Therefore, the TCD examination does not add any additional information. The
authors state the value of TCD in children is not in the primary diagnosis of disease but in the follow-up of
known vascular processes (e.g., stenosis) or in chronic diseases (e.g., sickle cell disease).

Professional Societies/Organizations
American Academy of Neurology (AAN):
The Therapeutics and Technology Assessment
Subcommittee of the AAN performed a systematic review of literature through June 2003. In its 2004
report, Assessment: Transcranial Doppler Ultrasonography, the subcommittee reviewed the sensitivity
and specificity of TCD and transcranial color-coded sonography (TCCS) for various disease states
(Sloan, et al., 2004). The major recommendations of the AAN's technology assessment of TCD
ultrasonography are listed below:

• Settings in which TCD ultrasonography is able to provide information and in which its clinical
utility is established:

screening of children age 2–16 years with sickle-cell disease for assessing stroke risk
detection and monitoring of angiographic VSP spontaneous subarachnoid hemorrhage
(sSaH)

• Settings in which TCD is able to provide information, but in which its clinical utility, compared with
other diagnostic tools, remains to be determined:

Intracranial steno-occlusive disease: TCD is probably useful for the evaluation of occlusive
lesions of intracranial arteries in the basal cisterns, especially the ICA siphon and middle
Page 7 of 14
Number: 0345


cerebral artery. Data are insufficient to recommend replacement of conventional angiography
with TCD.
Cerebral circulatory arrest (adjunctive test in the determination of brain death): If needed,
TCD can be used as a confirmatory test, in support of a clinical diagnosis of brain death.

• Settings in which TCD is able to provide information, but in which its clinical utility remains to be
determined:

Cerebral thrombolysis: TCD is probably useful for monitoring thrombolysis of acute middle
cerebral artery occlusions.
Cerebral microembolism detection: TCD monitoring is probably useful for the detection of
cerebral microembolic signals in a variety of cardiovascular/cerebrovascular
disorders/procedures. Data do not support the use of this TCD technique for diagnosis or
monitoring response to antithrombotic therapy in ischemic cerebrovascular disease.
CEA: TCD monitoring is probably useful to detect hemodynamic and embolic events that may
result in perioperative stroke during and after CEA in settings where monitoring is felt to be
necessary.
CABG surgery: TCD monitoring is probably useful during CABG for detection of cerebral
microemboli. TCD is possibly useful to document changes in flow velocities and carbon
dioxide (CO2) reactivity during CABG surgery.
VMR testing: TCD is probably useful for the detection of impaired cerebral hemodynamics in
patients with severe (>70%), asymptomatic extracranial ICA stenosis; symptomatic or
asymptomatic extracranial ICA occlusion; and cerebral small-artery disease.
VSP after traumatic subarachnoid hemorrhage (tSAH): TCD is probably useful for the
detection of VSP following tSAH.
TCCS: TCCS is possibly useful for the evaluation and monitoring of space-occupying
ischemic middle cerebral artery infarctions.

• Settings in which TCD is able to provide information, but in which other diagnostic tests are
typically preferable:

Right-to-left cardiac shunts: Whereas TCD is useful for detection of right-to-left cardiac and
extracardiac shunts, TEE is superior, as it can provide direct information regarding the
anatomical site and nature of the shunt.
Extracranial ICA stenosis: TCD is possibly useful for the evaluation of severe extracranial ICA
stenosis or occlusion but, in general, carotid duplex and MRA are the diagnostic tests of
choice.
Contrast-enhanced TCCS: Contrast-enhanced TCCS may provide information in patients
with ischemic cerebrovascular disease and aneurysmal subarachnoid hemorrhage (aSAH).

The current practice parameter on neuroimaging of the neonate by the AAN states routine screening
cranial ultrasonography should be performed on all infants < 30 weeks’ gestation once between 7–14
days of age and should be optimally repeated between 36–40 weeks’ postmenstrual age. This strategy
detects lesions such as intraventricular hemorrhage, periventricular leukomalacia, and low-pressure
ventriculomegaly. Currently ultrasound, CT, and MRI represent the major imaging modalities for
evaluation of critically ill infants. It appears that these recommendations have not been updated since
2002 (Ment, et al., 2002).

American College of Radiology (ACR): The 2007 ACR Practice Guideline for the Performance of TCD
Ultrasound for Adults and Children states that TCD is a noninvasive technique that assesses blood flow
within the circle of Willis and the vertebrobasilar system in children who have a closed anterior fontanelle
and in adults. The ACR indications for a TCD ultrasound examination include, but are not limited to:

Adults
• Detection of stenosis or occlusion in a major intracranial artery in the circle of Willis and
vertebrobasilar system, including monitoring thrombolytic therapy for acute stroke patients.
Page 8 of 14
Number: 0345


• Follow-up of patients with known stenosis or occlusion of a major intracranial artery in the circle of
Willis and vertebrobasilar system.
• Detection and monitoring of vasospasm in patients with subarachnoid hemorrhage.
• Detection of circulating emboli in a major intracranial artery in the circle of Willis and
vertebrobasilar system.
• Detection of right-to-left shunts using agitated saline injection.
• Assessment of vasomotor reactivity.
• Confirmation of the clinical diagnosis of brain death by detection of complete cerebral
circulatory arrest.
• Intraoperative and periprocedural monitoring to detect embolization, thrombosis, hypoperfusion,
and hyperperfusion.

Children
• Evaluation of stenosis or occlusion in the circle of Willis and vertebrobasilar system in patients
with sickle cell anemia to determine the need for and continuation of blood transfusions.
• Follow-up of patients with known stenosis or occlusion of an artery in the circle of Willis and
vertebrobasilar system in patients with sickle cell anemia.
• Detection of vasculopathy, such as moyamoya.
• Assessment of arteriovenous malformations.
• Confirmation of the clinical diagnosis of brain death by detection of complete cerebral circulatory
arrest in infants more than six months of age.

The ACR Practice Guideline for the Performance of Neurosonography in Neonates and Young Children
(2006a) was developed by the ACR and the American Institute of Ultrasound in Medicine (AIUM). It states
that neurosonographic examinations should be conducted with a real-time scanner, preferably with
transducers that can fit within and image through the anterior fontanelle. If the anterior fontanelle is not
available, imaging may be performed through other sutural openings or by using a transcranial approach,
usually with a lower-frequency transducer penetrating the squamosal portion of the temporal bone. The
transducer or scanner should be adjusted to operate at the highest clinically appropriate frequency,
recognizing that there is a trade-off between resolution and beam penetration. Doppler sonography or
color Doppler sonography may be used to evaluate intracranial blood flow in selected cases. It notes that
neonatal sonographic examinations should be performed on the neonate or young child (defined primarily
as those who have had no closure of the anterior fontanelle) for a valid reason, such as to determine the
presence or absence of hemorrhage, parenchymal abnormalities, ventricular dilation, congenital
abnormalities and vascular abnormalities.

American Society of Neuroimaging: The American Society of Neuroimaging Practice Guidelines
Committee, international neurosonological organizations, and experts in TCD have developed a practice
standard for TCD which is the first part of a series of practice standards for TCD. The authors report that
“scanning protocols, number of vessels, depth ranges for routine evaluation as well as reporting of TCD
examination vary between institutions. Given the emphasis on accreditation of vascular laboratories,
there is a need for standardization of scanning and interpretation processes.” Subsequent parts of the
series will detail specific TCD procedures, diagnostic criteria for interpretation of abnormal studies as well
as competency standards for neurovascular sonographers and interpreting physicians (Alexandrov, et al.,
2007).

Summary
The American Academy of Neurology's (AAN) Assessment: Transcranial Doppler (TCD) Ultrasonography
(2004) concluded that TCD is of established value in the screening of children age 2–16 years with sickle-
cell disease for stroke risk and the detection and monitoring of angiographic vasospasm (VSP) after
spontaneous subarachnoid hemorrhage (sSAH). The AAN report states that TCD monitoring is able to
provide information and is probably useful to detect hemodynamic and embolic events that may result in
perioperative stroke during and after carotid endarterectomy (CEA). Additionally, there is evidence in
peer-reviewed published studies and textbook literature that TCD is an accepted method for monitoring
cerebral blood flow to detect embolic events during and after CEA.

Page 9 of 14
Number: 0345


Although TCD may be able to provide some information, the diagnostic utility of TCD compared to that of
other established diagnostic tools remains to be determined for the evaluation of intracranial steno-
occlusive disease and in the determination of cerebral circulatory arrest/brain death. According to the
AAN report, the clinical utility of TCD has not been established for cerebral thrombolysis, cerebral
microembolism detection, coronary artery bypass graft (CABG) surgery, vasomotor reactivity (VMR)
testing (i.e., vasoreactive study), vasospasm after traumatic subarachnoid hemorrhage, and transcranial
color-coded sonography. Other diagnostic tests are typically preferable for right-to-left cardiac shunts and
extracranial internal carotid artery (ICA) stenosis.


Coding/Billing Information

Note:
This list of codes may not be all-inclusive.

When medically necessary:

CPT®*
Description
Codes
93886
Transcranial Doppler study of the intracranial arteries; complete study
93888
Transcranial Doppler study of the intracranial arteries; limited study

HCPCS
Description
Codes

No specific codes

ICD-9-CM
Description
Diagnosis
Codes
282.60–
Sickle-cell disease
282.69
430 Subarachnoid
hemorrhage
433.10–
Occlusion and stenosis of carotid artery
433.11

† Note: Limited to the use of transcranial Doppler ultrasonography as a screening method in
children age 2–16 years with sickle cell disease to assess stroke risk.

Experimental/Investigational/Unproven/Not medically necessary:

CPT* Codes
Description
93890
Transcranial Doppler study of the intracranial arteries; vasoreactivity
study
93892
Transcranial Doppler study of the intracranial arteries; emboli detection
without intravenous microbubble injection
93893
Transcranial Doppler study of the intracranial arteries; emboli detection
with intravenous microbubble injection

HCPCS
Description
Codes

No specific codes

ICD-9-CM
Description
Diagnosis
Codes
433.00–
Occlusion and stenosis of precerebral arteries
433.91
434.00–
Occlusion of cerebral arteries
Page 10 of 14
Number: 0345


Document Outline

  • ÿ

Download
Transcranial Doppler (TCD) Ultrasonography

 

 

Your download will begin in a moment.
If it doesn't, click here to try again.

Share Transcranial Doppler (TCD) Ultrasonography to:

Insert your wordpress URL:

example:

http://myblog.wordpress.com/
or
http://myblog.com/

Share Transcranial Doppler (TCD) Ultrasonography as:

From:

To:

Share Transcranial Doppler (TCD) Ultrasonography.

Enter two words as shown below. If you cannot read the words, click the refresh icon.

loading

Share Transcranial Doppler (TCD) Ultrasonography as:

Copy html code above and paste to your web page.

loading