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F C van Egmond

Publications and source records attributed to F C van Egmond.

6 recordsLinked to original sources
PubMed2000

A fast rotating scanning unit for real-time three-dimensional echo data acquisition.

Most three-dimensional (3-D) echocardiography (3-DE) systems today are based on off-line methods where a large number of cross-sectional 2-D scans have to be acquired sequentially before a 3-D image can be reconstructed. Because acquisition is done step-by-step based on ECG triggering plus respiratory gating, this introduces motion artefacts and takes significant acquisition time. Another 3-D approach is based on 2-D transducers and parallel beam-forming. Such a system is very complex. In this manuscript, a fast continuously-rotating scanning unit, based on a 64-element phased-array transducer, is described. Typical rotation speed of the 3-D unit is 8 rotations per s. Therefore, 16 3-D volume datasets can be acquired per s in real-time. The first clinical examples as acquired with this probe are presented.

Artifacts↗
PubMed1995

Comparison of intravascular ultrasonic findings after coronary balloon angioplasty evaluated in vitro with histology.

This study investigated whether vascular damage and quantitative changes observed with intravascular ultrasound at the most stenotic site are representative of the ultimate outcome after coronary balloon angioplasty. Atherosclerotic coronary arteries (n = 40) were studied in vitro with intravascular ultrasound. From each vascular specimen, 10 corresponding intravascular ultrasound cross sections obtained before and after balloon angioplasty were selected for comparison with their histologic counterpart. Morphologic and quantitative data obtained from all cross sections were compared with data derived from the most stenotic site. The incidence of vascular damage (i.e., dissection, plaque rupture, and media rupture) at the most stenotic site was lower than that seen for each vascular specimen. The sensitivity of intravascular ultrasound in detecting these morphologic features for each vascular specimen was high for dissection and media rupture (79% and 76%, respectively), and low for plaque rupture (37%). After balloon angioplasty, quantitative changes seen at the most stenotic site were greater than those in all cross sections: free lumen area +58% versus +29%, media-bound area +17% versus +12%, and plaque area reduction -9% versus -6%, respectively. The increase in free lumen area was caused predominantly by media-bound area increase (81%) and to a lesser extent by plaque area decrease (19%). This study revealed that a higher incidence of vascular damage is found when the whole segment is analyzed rather than 1 single cross section at the most stenotic site. Quantitative effects of coronary balloon angioplasty seen with intravascular ultrasound were greater at the most stenotic site than at all cross sections.

Adult↗
PubMed1991

Assessment of medial thinning in atherosclerosis by intravascular ultrasound.

This study investigated the in vitro (40 MHz) and in vivo (30 MHz) feasibility of intravascular ultrasound to document the influence of atherosclerotic lesions on the typical 3-layered appearance of muscular arteries. The in vitro images of 39 arteries were compared with the corresponding histologic sections. Media and lesion thickness were measured at the areas of minimal and maximal lesion thickness. The median media thickness was 0.8 mm in the absence of a lesion, decreasing to 0.3 mm in the area of maximal atherosclerosis. The ultrasonic data correlated closely with histologic measurements (0.6 and 0.3 mm, respectively). The in vivo study was performed in 29 patients undergoing coronary or peripheral vascular procedures. A total of 150 still-frames were selected for quantitative analysis. The median media thickness was 0.6 mm in the absence of a lesion, decreasing to 0.1 mm in the area with maximal atherosclerosis. This study revealed that intravascular ultrasound imaging accurately determines that media thickness of muscular arteries is inversely related to lesion thickness. In vitro data, verified with histology, can be translated to humans in vivo.

Arteries↗
PubMed1989

Arterial wall characteristics determined by intravascular ultrasound imaging: an in vitro study.

The feasibility of assessing arterial wall configuration with an intravascular 40 MHz ultrasound imaging device was investigated in an in vitro study of 11 autopsy specimens of human arteries. The system consists of a single element transducer, rotated with a motor mounted on an 8F catheter tip. Cross sections obtained with ultrasound were matched with the corresponding histologic sections. The arterial specimens were histologically classified as of the muscular or elastic type. Muscular arteries interrogated with ultrasound presented with a hypoechoic media, coinciding with the smooth muscle cells. In contrast, the media of an elastic artery densely packed with elastin fibers was as echogenic as the intima and the adventitia. On the basis of the cross-sectional image, it was possible to determine the nature of the atherosclerotic plaque. The location and thickness of the lesion measured from the histologic sections correlated well with the data derived from the corresponding ultrasound images. This study indicates that characterization of the type of artery and detection of arterial wall disease are possible with use of an intravascular ultrasound imaging technique.

Adult↗
PubMed1988

Intra-arterial ultrasonic imaging for recanalization by spark erosion.

Presently several new methods are being developed to recanalize obstructed arteries during catheterization. Intra-arterial high frequency ultrasonic imaging may be used as a guidance for these new techniques. Spark erosion is a new obstruction removal technology. Experiments have shown that this method can be applied in a selective way. An ultrasonic intra-arterial imaging system allows for the proper indication of the spark erosion catheter relative to the obstruction. The first in vitro results of this study illustrate that integration of catheter tip imaging and spark erosion is possible.

Angioplasty, Balloon↗