Quantitative 3·D Echocardiography of The Heart and The Coronary Vessels

The recognition of the existence of ultrasound is credited to L. Spallanzani (1729- 1799). In recent years, ultrasound has been used as an imaging modality in medicine. I. Edler and C.H. Hertz produced the first ultrasound images of the heart in 1953. In the 1960's great progress was made in the clinical application of ultrasound when real-time two-dimensional ultrasound scanners were developed. In 1968, J. Somer constructed the first electronic phased-array scanner and this technology is still the most widely used in ultrasound equipment. In 1974 F.E. Barber and colleagues produced a duplex scanner which integrated imaging with pulsed-wave Doppler measurements. C. Kasai and colleagues constmcted in 1982 the color-coded Doppler flow imaging system based on autocorrelation detection, providing a noninvasive "angiogram" simulation of normal and abnormal blood flow on a "beat-to-beat" basis. Transesophageal echocardiography became available to clinicians in 1985 due to the developments of 1. Soquet who invented the mono- and biplane electronic phased-array probel Echocardiography has become one of the most commonly used diagnostic imaging techniques in cardiology. The development of commercial 3-D echocardiographic equipment began in the early 1990's. In 1993 a technique allowing acquisition of tomographic parallel sliced data set of echocardiographic images of the heart with a lobster tail TEE probe, was 2 developed by the German based company "TomTec GmbH". The TEE probe had an imaging element which could be controlled by computer applying a stepping motor. They also developed an interface to the patient to record the respiration and R-R intervals. This allowed the acquisition of ultrasound images ECG-triggered and gated, which reduced motion artifacts caused by beat-to-beat and respiratory variations in cardiac dimensions and position. After the acquisition of a tomographic data set, the images were post-processed and with application of software interpolation algorithms, gaps in the data set could be filled. This post-processed data set could then be used to reconstruct 3-D volume rendered images of the heart. 3-D ultrasound provides cardiac images which more closely mimic actual anatomy'than 2-D cross-sectional linages, and may thus be easier to interpret

Dynamic Three-Dimensional Echocardiography Offers Advantages for Specific Site Pacing

We have developed a novel technique for specific site pacing

Evaluation of Four-Year Coronary Artery Response After Sirolimus-Eluting Stent Implantation Using Serial Quantitative Intravascular Ultrasound and Computer-Assisted Grayscale Value Analysis for Plaque Composition in Event-Free Patients

ObjectivesThis study sought to evaluate the long-term arterial response after sirolimus-eluting stent implantation.BackgroundSirolimus-eluting stents are effective in inhibiting neointimal hyperplasia without affecting plaque volume behind the stent struts at six months.MethodsSerial quantitative intravascular ultrasound and computer-assisted grayscale value analysis over four years were performed in 23 event-free patients treated with sirolimus-eluting stents.ResultsIn the first two years, the mean plaque volume (155.5 ± 42.8 mm3post-procedure and 156.8 ± 57.7 mm3at two years, p = 0.86) and plaque compositional change expressed as mean percent hypoechogenic tissue of the plaque behind the stent struts (78.9 ± 8.6% post-procedure and 78.2 ± 8.9% at two years, p = 0.67) did not significantly change. However, significant plaque shrinking (change in plaque volume = −18.4 mm3, p = 0.02) with an increase in plaque echogenicity (change in percent hypoechogenic tissue = −7.8%, p < 0.0001) was observed between two and four years. The mean neointimal volume increased over four years from 0 to 8.4 ± 5.8 mm3(p < 0.0001). However, no further statistically significant change occurred between two and four years (7.0 ± 6.7 mm3vs. 8.4 ± 5.8 mm3, p = 0.25).ConclusionsBetween two and four years after sirolimus-eluting stent implantation, peri-stent tissue shrank with a concomitant increase in echogenicity. These intravascular ultrasound findings suggest that late chronic artery responses may evolve for up to four years after sirolimus-eluting stent implantation. In addition, the fact that the neointima does not significantly change from two to four years may suggest that the biological phenomenon of a delayed healing response has begun to subside

Adjustment method for mechanical Boston scientific corporation 30 MHz intravascular ultrasound catheters connected to a Clearview console. Mechanical 30 MHz IVUS catheter adjustment.

Intracoronary ultrasound (ICUS) is often used in studies evaluating new interventional techniques. It is important that quantitative measurements performed with various ICUS imaging equipment and materials are comparable. During evaluation of quantitative coronary ultrasound (QCU) software, it appeared that Boston Scientific Corporation (BSC) 30 MHz catheters connected to a Clearview ultrasound console showed smaller dimensions of an in vitro phantom model than expected. In cooperation with the manufacturer the cause of this underestimation was determined, which is described in this paper, and the QCU software was extended with an adjustment. Evaluation was performed by performing in vitro measurements on a phantom model consisting of four highly accurate steel rings (perfect reflectors) with diameters of 2, 3, 4 and 5 mm. Relative differences (unadjusted) of the phantom were respectively: 15.92, 13.01, 10.10 and 12.23%. After applying the adjustment: -0.96, -1.84, -1.35 and -1.43%. In vivo measurements were performed on 24 randomly selected ICUS studies. These showed differences for not adjusted vs. adjusted measurements of lumen-, vessel- and plaque volumes of -10.1 +/- 1.5, -6.7 +/- 0.9 and -4.4 +/- 0.6%. An off-line adjustment formula was derived and applied on previous numerical QCU output data showing relative differences for lumen- and vessel volumes of 0.36 +/- 0.51 and 0.13 +/- 0.31%. 30 MHz BSC catheters connected to a Clearview ultrasound console underestimate vessel dimensions. This can retrospectively be adjusted within QCU software as well as retrospectively on numerical QCU data using a mathematical model