Protocol - Stroke Risk in Children with Sickle Cell Disease - TCDi

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Imaging Transcranial Doppler (TCDi) ultrasonography is an imaging technique that measures the blood flow velocity in large intracranial arteries. This TCDi protocol covers how to identify relevant intracranial landmarks and how to record and score TCDi results.

Specific Instructions

Results from Imaging Transcranial Doppler (TCDi) ultrasound should be interpreted by a medical doctor with expertise in TCDi in sickle cell disease (SCD). Additionally, the TCD results should be compared with published guidelines to determine if the subject should be receiving prophylactic red cell transfusion or require more frequent TCD or other monitoring.

The Working Group does not recommend angle correction of TCDi blood-flow velocities. Cut-points for blood flow velocities are currently based on uncorrected velocities, and new parameters need to be established for angle-corrected velocities. Instead of angle correction, investigators should optimize the velocities with various maneuvers to get the best angle by transducer position.

The Working Group notes that blood-flow velocities indicative of stroke risk can be obtained by either Transcranial Doppler (TCD) ultrasound or Imaging Transcranial Doppler (TCDi) ultrasonography. The choice of TCD or TCDi depends on the expertise and equipment available to investigators.

The Sickle Cell Disease Curative Therapy Working Group recommends that imaging transcranial doppler (TCDi) ultrasonography be performed in sickle cell patients undergoing hematopoietic cell transplant at one time point pre-transplant. Additionally, investigators should indicate whether the results from TCDi were the indication for transplant.




Imaging Transcranial Doppler Ultrasonography

Identifying Intracranial Landmarks and Major Cerebral Arteries

Krejza et al. (2000) provide standard parameters for the visualization of the anterior, middle, and posterior cerebral arteries through the temporal acoustic window in the thin temporal region of the skull.

Recording Imaging Transcranial Doppler Ultrasonography Results

Examiners should record the highest time-averaged mean blood-flow velocity using a 3-millimeter sample volume placed at the point of highest velocity as determined by color aliasing artifacts in the following arteries:

  • middle cerebral artery,
  • distal internal carotid artery,
  • anterior and posterior cerebral arteries, and
  • basilar artery.

Angle-corrected mean velocities can be obtained by automatic or manual tracing of the Doppler waveform. Uncorrected flow velocities are calculated for each artery as the product of angle-corrected velocities and the cosine of the recorded angle of insonation based on the Doppler equation.

Scoring of Uncorrected Flow Velocities

Normal: blood velocities less than 165 centimeters per second in all arteries.

Conditional: blood velocities greater than 165 centimeters per second but less than 200 centimeters per second in all arteries.

Abnormal: blood velocity of 200 centimeters per second or greater in either the internal carotid artery or the middle cerebral artery.

Personnel and Training Required

Imaging Transcranial Doppler (TCDi) ultrasonography should be administered by trained ultrasonographers and interpreted by clinicians (e.g., radiologists, neurologists, hematologists) with expertise in TCDi in children with sickle cell disease (SCD).

Equipment Needs

2 megahertz Doppler ultrasonogram with a 1.8 to 3.6 megahertz transducer.

Requirement CategoryRequired
Major equipment Yes
Specialized training Yes
Specialized requirements for biospecimen collection No
Average time of greater than 15 minutes in an unaffected individual Yes
Mode of Administration

Clinical examination and physical measurement


Toddler, Child, Adolescent


Children and adolescents aged 2 years and older with hemoglobin SS or beta-zero thalassemia disease and without a history of clinical stroke.

Selection Rationale

Transcranial Doppler (TCD) ultrasound is a valid and reliable method that has been shown in clinical trials to select children for prophylactic blood transfusion. In contrast to traditional TCD, imaging TCD allows direct visualization of the arteries under examination.



Human Phenotype Ontology Sickle Cell Anemia ORPHA:232 HPO
Human Phenotype Ontology Anemia OMIM:603903 HPO
caDSR Form PhenX PX821002 - Stroke Risk In Children With Sickle Cell Disease Tcdi 6254567 caDSR Form
Derived Variables


Process and Review

Not applicable.

Protocol Name from Source

Imaging Transcranial Doppler (TCDi) ultrasonography


Identifying Intracranial Landmarks and Major Cerebral Arteries

Krejza, J., Mariak, Z., Melhem, E. R., & Bert, R. J. (2000). A guide to the identification of major cerebral arteries with Transcranial Color Doppler Sonography. American Journal of Roentgenology, 174, 1297-1303.

Recording and Scoring Results

Arkuszewski, M., Krejza, J., Chen, R., Kwiatkowski, J. L., Ichord, R., Zimmerman, R., Ohene-Frempong, K., & Melhem, E.R. (2012). Sickle cell disease in children: Accuracy of imaging transcranial Doppler ultrasonography in detection of intracranial arterial stenosis. The Neuroradiology Journal, 25(4), 402-410.

General References

Adams, R. J., Brambilla, D., & Optimizing Primary Stroke Prevention in Sickle Cell Anemia (STOP 2) Trial Investigators. (2005). Discontinuing prophylactic transfusions used to prevent stroke in sickle cell disease. New England Journal of Medicine 353(26), 2769-2778.

Adams, R. J., McKie, V. C., Brambilla, D., Carl, E., Gallagher, D., Nichols, F. T., Roach, S., Abboud, M., Berman, B., Driscoll, C., Files, B., Hsu, L., Hurlet, A., Miller, S., Olivieri, N., Pegelow, C., Scher, C., Vichinsky, E., Wang, W., Woods, G., Kutlar, A., Wright, E., Hagner, S., Tighe, F., Lewin, J., Cure, J., Zimmerman, R. A., & Waclawiw, M. A. (1998). Stroke prevention trial in sickle cell anemia. Controlled Clinical Trials 19(1), 110-129.

Adams, R.J., McKie, V.C., Hsu, L., Files, B., Vichinsky, E., Pegelow, C., Abboud, M., Gallagher, D., Kutlar, A., Nichols, F.T., Bonds, D.R., & Brambilla, D. (1998). 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, 339(1), 5-11.

Jones, A., Granger, S., Brambilla, D., Gallagher, D., Vichinsky, E., Woods, G., Berman, B., Roach, S., Nichols, F., Adams, R. J. (2005). Can peak systolic velocities be used for prediction of stroke in sickle cell anemia? Pediatric Radiology, 35(1), 66-72.

Krejza, J., Chen, R., Romanowicz, G., Kwiatkowski, J.L., Ichord, R., Arkuszewski, M., Zimmerman, R., Ohene-Frempong, K., Desiderio, L., & Melhem, E. R. (2011). Sickle cell disease and transcranial Doppler imaging: Inter-hemispheric differences in blood flow Doppler parameters. Stroke, 42(1), 81-86.

Pavlakis, S. G., Rees, R. C., Huang, X., Brown, R. C., Casella, J. F., Iyer, R. V., Kalpatthi, R., Luden, J., Miller, S. T., Rogers, Z. R., Thornburg, C. D., Wang, W. C. & Adams, R. J. (2010). Transcranial doppler ultrasonography (TCD) in infants with sickle cell anemia: Baseline data from the BABY HUG trial. Pediatric Blood Cancer, 54, 256-259.

Platt, O. S. (2005). Preventing stroke in sickle cell anemia. New England Journal of Medicine, 353(26), 2743-2745.

Protocol ID


Export Variables
Variable Name Variable IDVariable DescriptiondbGaP Mapping
PX821002060000 Angle-corrected mean velocities by automatic more
tracing of the Doppler waveform. show less
PX821002070000 Angle-corrected mean velocities by manual more
tracing of the Doppler waveform. show less
PX821002030000 Highest time-averaged mean blood-flow more
velocity in the anterior cerebral artery show less
PX821002050000 Highest time-averaged mean blood-flow more
velocity in the basilar artery show less
PX821002020000 Highest time-averaged mean blood-flow more
velocity in the distal internal carotid artery show less
PX821002010000 Highest time-averaged mean blood-flow more
velocity in the middle cerebral artery. show less
PX821002040000 Highest time-averaged mean blood-flow more
velocity in the posterior cerebral artery show less
Neurology, Quality of Life, and Health Services
Measure Name

Stroke Risk in Children with Sickle Cell Disease

Release Date

July 30, 2015


A clinical test to measure the blood flow velocities in intracranial arteries. Elevated intracranial arterial blood flow rates are indicative of expanding vessel lesions and a subsequent increased risk of stroke.


This measure is used to stratify stroke risk in children to determine eligibility for prophylactic blood transfusion for stroke prevention.


stroke, Stroke risk, Blood velocity, Transcranial Doppler ultrasonography, TCD, Imaging Transcranial Doppler ultrasonography, TCDi, Brain, Blood flow, "Neurology, quality of life, and Health Services"

Measure Protocols
Protocol ID Protocol Name
821001 Stroke Risk in Children with Sickle Cell Disease - TCD
821002 Stroke Risk in Children with Sickle Cell Disease - TCDi

There are no publications listed for this protocol.