We thank Sharma et al. for their comments on our paper which shows that measuring microembolic signals with transcranial Doppler at the level of the basilar artery across the foramen magnum (transforaminal approach) is an alternative for the detection of right-to-left cardiac shunt (RLS) in the absence of temporal bone windows [
]. We entirely agree with their comments that other extratemporal approaches such as using the vertebral arteries [
- Perren F.
- Savva E.
- Landis T.
Transforaminal Doppler: an alternative to transtemporal approach for right-to-left cardiac shunt assessment.
J Neurol Sci. 2008; 273: 49-50
], the common carotid arteries or even more peripheral arteries such as the contralateral brachial or femoral arteries [
- Del Sette M.
- Dinia L.
- Rizzi D.
- Sugo A.
- Albano B.
- Gandolfo C.
Diagnosis of right-to-left shunt with transcranial Doppler and vertebrobasilar recording.
Stroke. 2007; 38: 2254-2256
] are alternatives for the detection of RLS. Moreover, it appears that a number of methodological factors, such as the use of power M-mode transcranial Doppler with its multiple gates [
- Daly K.J.
- Hutchinson S.
- McCollum C.N.
Can a peripheral artery be used to detect venous-to-arterial circulation shunts?.
Cerebrovasc Dis. 2007; 25: 111-114
], measuring MES in a sitting position [
- Spencer M.P.
- Moehring M.A.
- Jesurum J.
- Gray W.A.
- Olsen J.V.
- Reisman M.
Power M-mode transcranial Doppler for diagnosis of patent foramen ovale and assessing transcatheter closure.
J Neuroimaging. 2004; 14: 342-349
], the addition of blood and increased agitation of the mixture [
- Lao A.Y.
- Sharma V.K.
- Tsivgoulis G.
- Malkoff M.D.
- Alexandrov AV Frey J.L.
Effect of body positioning during transcranial Doppler detection of right-to-left shunts.
Eur J Neurol. 2007; 14: 1035-1039
], or the use of galactose based contrast agent during Valsalva's maneuver [
- Sastry S.
- Daly K.
- Chengodu T.
- McCollum C.
Is transcranial Doppler for the detection of venous-to-arterial circulation shunts reproducible?.
Cerebrovasc Dis. 2007; 23: 424-429
], may all enhance sensitivity of the detection of RLS. All these methods achieve a detection of RLS with slightly different degrees of excellence and a good correlation with transesophageal echocardiography. However, as Sharma et al. point out, there exists actually no widely accepted protocol for the “best” procedure.
- Uzuner N.
- Horner S.
- Pichler G.
- Svetina D.
- Niederkorn K.
Right-to-left shunt assessed by contrast transcranial Doppler sonography: new insights.
J Ultrasound Med. 2004; 23: 1475-1482
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- Transforaminal Doppler: an alternative to transtemporal approach for right-to-left cardiac shunt assessment.J Neurol Sci. 2008; 273: 49-50
- Diagnosis of right-to-left shunt with transcranial Doppler and vertebrobasilar recording.Stroke. 2007; 38: 2254-2256
- Can a peripheral artery be used to detect venous-to-arterial circulation shunts?.Cerebrovasc Dis. 2007; 25: 111-114
- Power M-mode transcranial Doppler for diagnosis of patent foramen ovale and assessing transcatheter closure.J Neuroimaging. 2004; 14: 342-349
- Effect of body positioning during transcranial Doppler detection of right-to-left shunts.Eur J Neurol. 2007; 14: 1035-1039
- Is transcranial Doppler for the detection of venous-to-arterial circulation shunts reproducible?.Cerebrovasc Dis. 2007; 23: 424-429
- Right-to-left shunt assessed by contrast transcranial Doppler sonography: new insights.J Ultrasound Med. 2004; 23: 1475-1482
Published online: February 04, 2009
Accepted: January 6, 2009
Received: December 28, 2008
© 2009 Elsevier B.V. Published by Elsevier Inc. All rights reserved.