She was admitted to hospital in 1979 to evaluate her progressively limited exercise capacity. On examination she was a thin girl, 144 cm in height and 29 kg in weight. Her lips were mildly cyanosed. The peripheral pulses were normal and peripheral oedema was not present. Her blood pressure was 115/80 mmHg, with a heart rate of 80 beats per minute. The first sound was closely split. A grade 4/6 rough midsystolic murmur was audible in the second intercostal space at the left sternal border. In addition, a grade 3 protodiastolic murmur was heard best in the third intercostal space. The second heart sound was split. These findings were confirmed by phonocardiography.Chest x-ray film showed normal heart size, with dilatation of the pulmonary conus. Electrocardiography showed a PR interval of 0*18 second and evidence of right atrial and ventricular hypertrophy.The M-mode echocardiogram, performed with the Echocardio Visor single element, showed multiple "blurred" echoes in diastole posterior to the anterior leaflet of the tricuspid valve (Fig. 1A). These echoes were also seen in the right ventricular outflow tract. There was no interval between the tricuspid valve opening and the appearance of these "blurred" echoes. At the level of the pulmonary valve a discrete echo structure lying anterior to the valve was detected. This echo structure moved posteriorly with the onset of systole, shortly after the opening of the pulmonary valve (Fig. IB, see arrow).When the heart was examined with a dynamically focused Multiscan system,7 an abnormal thin walled

This study investigated the accuracy and reproducibility of a computer-aided method for quantification of intravascular ultrasound. The computer analysis system was developed on an IBM compatible PC/AT equipped with a framegrabber. The quantitative assessment of lumen area, lesion area and percent area obstruction was performed by tracing the boundaries of the free lumen and original lumen.Accuracy of the analysis system was tested in a phantom study. Echographic measurements of lumen and lesion area derived from 16 arterial specimens were compared with data obtained by histology. The differences in lesion area measurements between histology and ultrasound were minimal (mean _+ SD: -0.27 + 1.79 mm 2, p > 0.05). Lumen area measurements from histology were significantly smaller than those with ultrasound due to mechanical deformation of histologic specimens ( -5.38 + 5.09 mm 2, p < 0.05). For comparison with angiography, 18 ultrasound cross-sections were obtained in vivo from 8 healthy peripheral arteries. Luminal areas obtained by angiography were similar to those by ultrasound ( -0.52 + 5.15 mm 2, p > 0.05). Finally, intra-and interobserver variability of our quantitative method was evaluated in measurements of 100 in vivo ultrasound images. The results showed that variations in lumen area measurements were low (5 %) whereas variations in lesion area and percent area obstruction were relatively high (13 %, 10%, respectively).Results of this study indicate that our quantitative method provides accurate and reproducible measurements of lumen and lesion area. Thus, intravascular ultrasound can be used for clinical investigation, including assessment of vascular stenosis and evaluation of therapeutic intervention.

SummaryIn vivo application of intravascular high frequency ultrasonic imaging for peripheral and coronary artery disease is a promising technique for vascular surgeons, radiologists and cardiologists. This report demonstrates in vitro results obtained with a high frequency imaging catheter (40 MHz) in 70 human specimens including arteries with and without atherosclerosis, veins, coronary artery bypass grafts and vascular prosthetic material. Correlation between the ultrasonic images and the histologic characteristics of the corresponding vessel wall tissue and lumen geometry was established. In addition, the effect of intervention techniques i.e. balloon angioplasty, spark erosion and laser were studied with ultrasound and histology. It is anticipated that development of such a catheter imaging technique has potential for diagnostic imaging and for combination with therapeutic systems.

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The history of intraluminal echography dates back to the very beginning of diagnostic ultrasound. Over the years many fascinating ideas and applications of catheter tip or gastroscopic tube tip mounted transducers have been described. This chapter surveys these methods, subdividing them into a) measurements; b) Doppler and c) imaging. The survey ranges from early work of Cieszynski on the feasibility of echocardiography to more recent intra-arterial catheter tip Doppler with guidewire and balloon as described by Serruys. Examples of ultrasound catheter tip echography in combination with other techniques such as angioscopy, laser ablation and spark erosion are also described. Today practical approaches are limited to imaging only. The three major approaches for catheter tip echo imaging are described and compared. This paper concludes with the results of automatic contour analysis of the inner arterial boundaries.