Related Experiment Video
Updated: Feb 15, 2026

Functional Transcranial Doppler Ultrasound for Monitoring Cerebral Blood Flow
Published on: March 15, 2021
Lower Transcranial Doppler Flow Velocities in Sickle Cell Anemia Patients on Hydroxyurea: Myth or Fact
Sawsan M Moeen1, Ahmad F Thabet1, Hosam A Hasan2
11Clinical Hematology Unit, Department of Internal Medicine, Faculty of Medicine, Assiut University, Assiut, Egypt.
Abstract:
Transcranial Doppler (TCD) detects stroke risk in patients with sickle cell anemia (SCA). Hydroxyurea therapy has the ability to induce increased levels of fetal hemoglobin in sickle cells thus decreasing tendency for red cell sickling. This study aimed to evaluate TCD findings in SCA patients on hydroxyurea and correlate the time-averaged mean velocity (TAMV) with their hematological parameters. Forty SCA patients of both sexes, aged 16-22 years with no history of stroke were screened with TCD for an elevated TAMV, divided into: Group T (20 patients on blood transfusion); and Group H (20 patients on daily hydroxyurea). For all, full medical history, clinical examination, hemoglobin, hematocrit, leukocytes, platelets, fetal hemoglobin and sickling test, in addition TCD to describe the pattern of cerebral blood flow abnormalities were done. TAMV in all cerebral arteries were significantly higher in Group T than Group H, the highest TAMV (147.5 ± 57.09 cm/s) was found in the right middle cerebral artery and correlated negatively with hematocrit in Groups H (P < 0.001). There were 2 (10%) abnormal TAMV results and 5 (25%) conditional in Group T, while all results were normal in Group H. Hydroxyurea therapy may lower TCD velocities and prevent the risk of primary stroke in SCA patients.
More Related Videos
05:23Continuous Manual Exchange Transfusion for Patients with Sickle Cell Disease: An Efficient Method to Avoid Iron Overload
Published on: March 14, 2017
07:44Assessment of Cerebral Lateralization in Children using Functional Transcranial Doppler Ultrasound fTCD
Published on: September 27, 2010
Related Concept Videos
Velocity and Acceleration in Steady and Unsteady Flow
The acceleration can be generalized to any point in the flow, and expressed as components along three perpendicular directions, representing changes in velocity over...
Doppler Effect - I
Doppler Effect - II
Average Velocity
Instantaneous Velocity - II
Escape Velocity
To calculate the escape velocity, it is assumed that no energy is lost to any frictional forces. In practice, a satellite...