Result of TCD

Cerebral Blood Flow Velocity (cm/s)

Frequency of exam

Absence of window

-

Use other imaging resource to analyze cerebrovascular events.

Technical difficulty due to lack of cooperation

-

Repeat every three months; evaluation by another examiner.

Low cerebral blood flow velocity

70

Repeat after 1 month.

Normal cerebral blood flow velocity

<170

Repeat annually.

Low conditional

Between 170 and 184

Repeat at three-month intervals. If the subsequent results are normal, adopt the normal conduct.

High conditional

Between 185 and 199

Repeat after 1 month. In case of unchanged examinations, it is recommended to repeat every three months. In case of two consecutive abnormal results, it is recommended to discuss the risk of strokes and consider a chronic transfusion regimen.

Abnormal

Between 200 and 219

Repeat after 1 month.

If the velocity remains higher or equal to 200, it is recommended to discuss the risk of strokes and consider chronic transfusion regimen.

If the result decreases to 170-199, it is recommended to repeat it after one month (if high conditional—between 185 and 199); or repeat it after 6 months (if conditional low—between 170 and 184).

If the result is normalized (<170), it is recommended to repeat in 1 year.

More than 220

Discuss imminent risk of strokes and consider chronic transfusion regimen.