Transcranial Doppler, MRA, and MRI as a screening examination for cerebrovascular disease in patients with sickle cell anemia: an 8-year study

Abstract

Objective. The authors previously reported five transcranial Doppler ultrasonography (TCD) findings as significant in detecting clinical cerebrovascular disease in a 4-year study in patients with sickle cell disease. This is a follow-up to evaluate the validity of the original findings over another 4-year period during which the study population doubled. A clinical follow-up of the original asymptomatic sickle cell patients with positive TCD, MRA, and MRI was also made. Materials and methods. Over an 8-year period TCD, MRI, and MRA were prospectively performed in 90 sickle cell patients who were clinically asymptomatic for stroke and in 27 sickle cell patients with clinical stroke. Results. Of the 4 out of original 46 control patients in 1992 who had positive MRA and TCD, 3 have subsequently had clinical stroke. None of the 9 original patients with positive TCD and positive MRI but negative MRA have developed stroke. All five original TCD indicators of disease were still significant (P < 0.05) for detecting clinical disease: maximum velocity in ophthalmic artery (OA) > 35 cm/s, mean velocity in middle cerebral artery (MCA) > 170 cm/s, resistive index (RI) in OA < 50, velocity in OA greater than in MCA, and velocity in posterior cerebral (PCA), vertebral, or basilar arteries greater than in MCA. Four additional factors were also significant: turbulence, PCA or ACA without MCA, RI < 30, and maximum velocity in MCA > 200 cm/s. Conclusion. Positive MRA with a positive TCD in an asymptomatic patient in long-term follow-up suggests a trend for developing clinical stroke. A 4- to 8-year follow-up of nine patients with positive TCD, positive MRI, but not positive MRA did not show development of clinical stroke. Nine Doppler findings are significant in screening for clinically symptomatic vascular disease in sickle cell patients. It is recommended that children with sickle cell disease be screened for cerebrovascular disease with TCD. If one or two indicators of abnormality are present, MRA is recommended. If the MRA is positive, the patient may be considered for transfusion therapy or other treatment for prevention of stroke.