Contrast transcranial Doppler ultrasound in the detection of right-to-left shunts. Reproducibility, comparison of 2 agents, and distribution of microemboli.
OBJECTIVE
Cardiac right-to-left shunts can be identified by transcranial Doppler ultrasound (TCD) with the use of different contrast agents and by transesophageal echocardiography (TEE). Systematic data are available on neither the reproducibility of contrast TCD, the comparison of different contrast agents, nor the comparison of simultaneous bilateral to unilateral recordings. Furthermore, we assessed the side distribution of thus provoked artificial cardiac emboli.


METHODS
Fifty-four patients were investigated by TEE and by bilateral TCD of the middle cerebral artery. The following protocol was performed twice: injection of 9 mL of agitated saline without Valsalva maneuver, injection of 9 mL of agitated saline with Valsalva maneuver, injection of 5 mL of a commercial galactose-based contrast agent without Valsalva maneuver, and injection of 5 mL of the galactose-based contrast agent with Valsalva maneuver.


RESULTS
In 18 patients, a right-to-left shunt was demonstrated by TEE and contrast TCD (shunt positive). Twenty-nine patients were negative in both investigations, 1 was positive on TEE and negative on TCD, and 6 patients were only positive on TCD. Both bilateral and repeated recordings increased the sensitivity of contrast TCD. There was a symmetrical distribution of microembolic signals in the right and left middle cerebral artery.


CONCLUSIONS
TCD performed twice and with the use of saline or a galactose-based contrast agent is a sensitive method in the identification of cardiac right-to-left shunts also identified by TEE. The cardiac microemboli in this study did not show any side preference for one of the middle cerebral arteries.
Droste
D W
DW
Department of Neurology, Department of Cardiology and Angiology and Institute of Arteriosclerosis Research, University of Münster, Germany.
Reisener
M
M
Kemény
V
V
Dittrich
R
R
Schulte-Altedorneburg
G
G
Stypmann
J
J
Wichter
T
T
Ringelstein
E B
EB
D000328:Adult; D000368:Aged; D002560:Cerebrovascular Circulation; D003287:Contrast Media; D004452:Echocardiography; D005260:Female; D007839:Functional Laterality; D006344:Heart Septal Defects, Atrial / Q000000981:diagnostic imaging*; D006801:Humans; D002542:Intracranial Embolism and Thrombosis / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods* / Q000592:standards*; D014636:Valsalva Maneuver
D003287:Contrast Media