Stroke, Vol 24, 1246-1250, Copyright © 1993 by American Heart Association
H Markus
BACKGROUND: The identification of gaseous emboli using Doppler ultrasound
was described as early as the 1960s. Recently it has been demonstrated that
this method can also detect solid emboli such as thrombi and platelet
aggregates. This may make this technology useful in a large number of
patients with, or at risk of, embolic stroke. SUMMARY OF REVIEW: Emboli
appear as short-duration, high-intensity signals in the Doppler spectrum.
The intensity of the Doppler signal from an artery containing an embolus
depends on the density difference between the embolic material and blood.
This difference is greatest for gaseous emboli, which are therefore the
most easy to detect. Gaseous emboli have been demonstrated during deep-sea
diving, and their presence correlates with the occurrence of decompression
sickness. Similar signals have been detected during cardiopulmonary bypass.
A relation has been demonstrated between the number of emboli detected by
transcranial Doppler and a decline in neuropsychological function after
cardiopulmonary bypass. Solid emboli such as thrombi and platelet
aggregates result in less intense signals than air emboli. Their detection,
using Doppler ultrasound, has recently been described in patients with
prosthetic heart valves, atrial fibrillation, and carotid artery disease.
It may also help in the detection and localization of embolic sources in
patients with stroke. Studies in in vitro and in vivo models demonstrate
that this technique provides information on the size and type of emboli.
Larger emboli produce signals of greater intensity and duration. Practical
patient monitoring will require automatic emboli detectors incorporated
into the Doppler machine; such programs are being developed. CONCLUSIONS:
Detection of solid emboli using Doppler techniques offers an exciting new
diagnostic tool. It has been demonstrated that the technique can detect
solid emboli. The prognostic significance of such emboli remains to be
determined. It is hoped that the technique will allow detection of patients
at high risk of embolic stroke in whom appropriate prophylactic treatment
can then be instituted.
ARTICLES
Transcranial Doppler detection of circulating cerebral emboli. A review
Division of Clinical Neuroscience St George's Hospital Medical School, London, UK.
This article has been cited by other articles:
 |
|
 |
|
  L. R. Caplan A 70-Year-Old Man With a Transient Ischemic Attack: Review of Internal Carotid Artery Stenosis JAMA, July 2, 2008; 300(1): 81 - 90. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. D.C. Sauren, M. la Meir, M. Palmen, E. Severdija, F. H. van der Veen, W. H. Mess, and J. G. Maessen New ultrasonic radiation reduces cerebral emboli during extracorporeal circulation Eur. J. Cardiothorac. Surg., August 1, 2007; 32(2): 274 - 280. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Colangelo, L. Torracca, E. Lapenna, S. Moriggia, G. Crescenzi, and O. Alfieri Vacuum-assisted venous drainage in extrathoracic cardiopulmonary bypass management during minimally invasive cardiac surgery. Perfusion, November 1, 2006; 21(6): 361 - 365. [Abstract] [PDF]
|
|
|
|
 |
|
 M. Barak and Y. Katz Microbubbles: Pathophysiology and Clinical Implications Chest, October 1, 2005; 128(4): 2918 - 2932. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Perthel, S. Kseibi, A. Bendisch, and J. Laas Use of a dynamic bubble trap in the arterial line reduces microbubbles during cardiopulmonary bypass and microembolic signals in the middle cerebral artery Perfusion, May 1, 2005; 20(3): 151 - 156. [Abstract] [PDF]
|
|
|
|
 |
|
 I. Momjian-Mayor and J.-C. Baron The Pathophysiology of Watershed Infarction in Internal Carotid Artery Disease: Review of Cerebral Perfusion Studies Stroke, March 1, 2005; 36(3): 567 - 577. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. A Rodriguez, K. A Williams, A. Babaev, F. Rubens, and H. J Nathan Effect of perfusionist technique on cerebral embolization during cardiopulmonary bypass Perfusion, January 1, 2005; 20(1): 3 - 10. [Abstract] [PDF]
|
|
|
|
|
|
S. Milo, E. Rambod, C. Gutfinger, and M. Gharib Mitral mechanical heart valves: in vitro studies of their closure, vortex and microbubble formation with possible medical implications Eur. J. Cardiothorac. Surg., September 1, 2003; 24(3): 364 - 370. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Perthel, S. Kseibi, A. Bendisch, and J. Laas The dynamic bubble trap reduces microbubbles in extracorporeal circulation and high intensity transient signals in the middle cerebral artery: a case report Perfusion, September 1, 2003; 18(5): 325 - 329. [Abstract] [PDF]
|
|
|
|
 |
|
 U. Junghans and M. Siebler Cerebral Microembolism Is Blocked by Tirofiban, a Selective Nonpeptide Platelet Glycoprotein IIb/IIIa Receptor Antagonist Circulation, June 3, 2003; 107(21): 2717 - 2721. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G.C. Cloud and H.S. Markus Diagnosis and management of vertebral artery stenosis QJM, January 1, 2003; 96(1): 27 - 54. [Full Text] [PDF]
|
|
|
|
 |
|
 G. Orlandi, S. Fanucchi, C. Fioretti, G. Acerbi, M. Puglioli, R. Padolecchia, F. Sartucci, and L. Murri Characteristics of Cerebral Microembolism During Carotid Stenting and Angioplasty Alone Arch Neurol, September 1, 2001; 58(9): 1410 - 1413. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. A. Rodriguez, G. Cornel, N. A. Weerasena, and W. M. Splinter Effect of Trendelenburg head position during cardiac deairing on cerebral microemboli in children: A randomized controlled trial J. Thorac. Cardiovasc. Surg., January 1, 2001; 121(1): 0003 - 9. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Markus, M. Cullinane, and G. Reid Improved Automated Detection of Embolic Signals Using a Novel Frequency Filtering Approach Stroke, August 1, 1999; 30(8): 1610 - 1615. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Molloy, J. F. Martin, P. A. Baskerville, S. C. A. Fraser, and H. S. Markus S-Nitrosoglutathione Reduces the Rate of Embolization in Humans Circulation, October 6, 1998; 98(14): 1372 - 1375. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. W. M. Keunen, C. J. Stam, D. L. J. Tavy, W. H. Mess, B. M. Titulaer, and R. G. A. Ackerstaff Preliminary Report of Detecting Microembolic Signals in Transcranial Doppler Time Series With Nonlinear Forecasting Stroke, August 1, 1998; 29(8): 1638 - 1643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Valdueza, L. Harms, F. Doepp, J. Koscielny, and K. M. Einhaupl Venous Microembolic Signals Detected in Patients With Cerebral Sinus Thrombosis Stroke, August 1, 1997; 28(8): 1607 - 1609. [Abstract] [Full Text]
|
|
|
|
 |
|
 C. Specker, J. Rademacher, D. Sohngen, M. Sitzer, I. Janda, M. Siebler, H. Steinmetz, and M. Schneider Cerebral microemboli in patients with antiphospholipid syndrome Lupus, January 1, 1997; 6(8): 638 - 644. [Abstract] [PDF]
|
|
|
|
|
|
M. Kurusz, B. D Butler, J. Katz, and V. R Conti Air embolism during cardiopulmonary bypass Perfusion, November 1, 1995; 10(6): 361 - 391. [PDF]
|
|
|
|
|
|
U. Sliwka, F.-P. Job, D. Wissuwa, R. R. Diehl, F.-A. Flachskampf, P. Hanrath, and J. Noth Occurrence of Transcranial Doppler High-Intensity Transient Signals in Patients With Potential Cardiac Sources of Embolism : A Prospective Study Stroke, November 1, 1995; 26(11): 2067 - 2070. [Abstract] [Full Text]
|
|
|
|
|
|
M. Sitzer, W. Muller, M. Siebler, W. Hort, H.-W. Kniemeyer, L. Jancke, and H. Steinmetz Plaque Ulceration and Lumen Thrombus Are the Main Sources of Cerebral Microemboli in High-grade Internal Carotid Artery Stenosis Stroke, July 1, 1995; 26(7): 1231 - 1233. [Abstract] [Full Text]
|
|
|
|
|
|
L. Valton, V. Larrue, P. Arrue, G. Geraud, and A. Bes Asymptomatic Cerebral Embolic Signals in Patients With Carotid Stenosis : Correlation With Appearance of Plaque Ulceration on Angiography Stroke, May 1, 1995; 26(5): 813 - 815. [Abstract] [Full Text]
|
|
|
|
|
|
M. Sturzenegger, J. H. Beer, and F. Rihs Monitoring Combined Antithrombotic Treatments in Patients With Prosthetic Heart Valves Using Transcranial Doppler and Coagulation Markers Stroke, January 1, 1995; 26(1): 63 - 69. [Abstract] [Full Text]
|
|