Related Experiment Video
Updated: Aug 11, 2026
Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
Transcranial Doppler (TCD) screening for stroke prevention in sickle cell anemia: pitfalls in technique variation
D I Bulas1, A Jones, J J Seibert
1Department of Radiology and Diagnostic Imaging, Children's National Medical Center, Washington, DC 20010, USA. dbulas@cnmc.org
Insights
Transcranical Doppler imaging (TCDI) shows lower velocities than transcranial Doppler (TCD) in children with sickle cell disease. These differences impact stroke risk assessment and prophylactic transfusion decisions based on the STOP protocol.
Area of Science:
- Neurology
- Pediatrics
- Medical Imaging
Background:
- Sickle cell anemia poses a high stroke risk in children.
- The Stroke Prevention Trial in Sickle Cell Anemia (STOP) protocol uses transcranial Doppler (TCD) to identify high-risk individuals based on specific velocity thresholds.
- Concerns exist regarding the comparability of TCD measurements obtained with different ultrasound devices and techniques.
Purpose of the Study:
- To compare findings between nonimaging TCD and transcranial duplex imaging (TCDI) in children with sickle cell disease.
- To evaluate the consistency of stroke risk assessment using these two ultrasound modalities.
Main Methods:
- Twenty-two children with sickle cell disease underwent both TCD and TCDI examinations on the same day.
- Examinations were conducted independently, with manual measurements recorded for both techniques.
- Comparisons were made for mean, peak systolic, and end-diastolic velocities, including a subgroup analysis of manual versus electronic measurements.
Main Results:
- Transcranial Doppler imaging (TCDI) consistently yielded lower velocity measurements across all evaluated intracranial arteries compared to TCD.
- Time-averaged maximum mean velocity (TAMMV) differences were smallest in the middle cerebral artery (-9.0%) and distal internal carotid artery (-10.8%).
- Despite velocity differences, risk stratification based on middle cerebral artery TAMMV remained consistent between TCD and TCDI.
Conclusions:
- Velocity measurements obtained via TCDI tend to be lower than those from TCD.
- These discrepancies necessitate careful consideration during stroke risk screening and selection for prophylactic transfusions in sickle cell disease patients.
- The findings highlight the importance of understanding modality-specific differences for accurate application of the STOP protocol.
Background:
The Stroke Prevention Trial in Sickle Cell Anemia (STOP) identified children as being at high stroke risk if the time-averaged maximum mean velocity (TAMMV) of the middle cerebral or intracranial internal carotid arteries measured > or = 200 cm/s. These values were obtained utilizing a 2-mHz dedicated nonimaging pulsed Doppler technique (TCD) and manual measurements. Questions have been raised as to the comparability of results obtained with different ultrasound machines and measurement techniques.
Objective:
The purpose of this study was to compare nonimaging (TCD) and transcranial duplex imaging (TCDI) findings in children potentially at risk for stroke with sickle cell disease.
Materials And Methods:
Twenty-two children with sickle cell disease and no history of stroke were evaluated by both TCD and TCDI. Examinations were performed on the same day without knowledge of the other modality results and read independently using manually obtained measurements. Mean velocities, peak systolic velocities, and end diastolic velocities obtained by the two techniques were compared. In a subgroup, manual measurements were compared to electronically obtained measurements.
Results:
TCDI values were lower than TCD measurements for all vessels. TCDI TAMMV values were most similar to the TCD values in the middle cerebral artery (-9.0%) and distal internal cerebral artery (-10.8%), with greater variability in the anterior cerebral artery (-19.3%), bifurcation (-16.3%), and basilar arteries (-23.1%). Risk group placement based on middle cerebral artery TAMMV values did not change when comparing the two techniques. Measurements obtained electronically were lower than those obtained manually.
Conclusion:
Velocities obtained by TCDI may be lower than TCD measurements, and these differences should be taken into consideration when performing screening for stroke risk and selection for prophylactic transfusion based on the STOP protocol.
