Sensitivity of Transcranial Doppler Versus Intracardiac Echocardiography in the Detection of Right-to-Left Shunt

Division of Cardiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA.
JACC. Cardiovascular imaging (Impact Factor: 6.99). 04/2010; 3(4):343-8. DOI: 10.1016/j.jcmg.2009.12.012
Source: PubMed

ABSTRACT The purpose of this study was to understand the reason for variation in the sensitivity of different methods of detecting right-to-left shunts (RLS).
Patent foramen ovale (PFO) is implicated in the pathogenesis of cryptogenic stroke, decompression illness, and migraine headaches. Intravenous agitated saline injections with tomographic imaging (transthoracic, transesophageal, and intracardiac echocardiography) has been used for detecting intracardiac shunts. Some patients with a high clinical suspicion of PFO have inconclusive echocardiographic study results. Transcranial Doppler (TCD) is an alternative method for detecting RLS that is not dependent on tomographic imaging.
Thirty-eight consecutive patients who were undergoing PFO closure had simultaneous transcranial Doppler and intracardiac echocardiography performed. Agitated saline injections were performed at rest, with Valsalva maneuver, and with forced expiration into a manometer to 40 mm Hg before and after closure, as well as 3 or more months after closure. Right atrial pressures were measured in the periprocedural period, and RLS were graded according to standard methods during these maneuvers.
Right atrial pressures were significantly higher with Valsalva maneuver compared with rest (before closure 21.6 +/- 11.9 mm Hg vs. 6.6 +/- 2.6 mm Hg, p < 0.001; after closure 28.4 +/- 13.9 mm Hg vs. 6.8 +/- 2.6 mm Hg, p < 0.001) and with manometer compared with Valsalva maneuver (before closure 38.7 +/- 6.6 mm Hg vs. 21.6 +/- 11.9 mm Hg, p < 0.001; after closure 44.0 +/- 9.5 mm Hg vs. 28.4 +/- 13.9 mm Hg, p < 0.001). Intracardiac echocardiography underestimated shunting in 34% of patients with Valsalva maneuver or manometer after closure compared with TCD.
Transcranial Doppler with immediate feedback provided by forced expiration against a manometer to 40 mm Hg is more sensitive than echocardiographic imaging for the detection of RLS. These observations have significant implications for determining the incidence of RLS in patients with stroke or migraine.

  • [Show abstract] [Hide abstract]
    ABSTRACT: First Page of the Article
    IEEE 1987 Ultrasonics Symposium; 02/1987
  • [Show abstract] [Hide abstract]
    ABSTRACT: Summary form only given, as follows. A promising approach to implementing electronic neural networks is to design and fabricate special-purpose VLSI chips, because the software execution of simulated annealing on conventional computers is very slow. A hardware realization of simulated annealing is described using the analog between the temperature in the Boltzmann machine and the amplifier gain in the electronic neural circuits. Detailed requirements for the annealing schedule are analyzed. Experimental results on the transfer characteristics of 4-bit Hopfield neural-based analog-to-digital converters with the simulated annealing technique are presented
  • [Show abstract] [Hide abstract]
    ABSTRACT: With the introduction of low-k materials into the intermetal dielectric (IMD) layers, it is important to optimize the via etch process in order to minimize the IMD degradation that is caused by harsh O<sub>2</sub> and wet stripping treatments. A simple, sensitive, and cost-effective measurement method is introduced for the determination of low-k material degradation caused during the via etch process. By using a single damascene comb structure, a large sidewall area of low-k material can be exposed to the etch strip process in question. The intra-line capacitance between the trenches is an extremely sensitive parameter to evaluate material degradation. Using this method, etch and strip processes can be tailored for a specific low-k material, which in turn, improve the interconnect performance and via yield. The results from this method are identical to results coming from the optimization of electrical performance with completely integrated chips and is in very good agreement with FTIR analysis for bare films
    Interconnect Technology, 1999. IEEE International Conference; 02/1999
Show more


Available from