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A 2 MHz continuous waveform noninvasive ultrasound doppler system has been used in the present investigation. With the aid of the audio signals of the frequency shifts, the ultrasound probe was positioned on the external chest so that the axis of the incident ultrasonic beam coincided with the direction of the maximum velocity vectors of the mitral jet. The frequency shifts due to the mitral jet were frequency analyzed and the time course of the maximum frequency shitl was determined. The time course of the maximum mitral jet velocity was then determined from the doppler equation and the time course of the mitral pressure gradient from an orifice equation. The usefulness of the technique was evaluated by studying 25 patients with mitral stenosis and 10 without heart disease. The patients with mitral stenosis were studied during cardiac catheterization and the ultrasound data, the pulmonary artery wedge pressure, and the left ventricular pressure were recorded simultaneously. A table is presented where the gradient determined with the ultrasound technique, Mu, is compared with the gradient determined from the pressure tracings, APM. Averaged over the 25 patients studied, APU was 1.7 mmHg smaller than

The presence of carotid ulceration was assessed by two readers for 55 B-mode ultrasound (US) studies. Intact surgical specimens were available for comparison. Ulceration was considered present if the following criteria were obtained: a continuous contour showing focal depression, a well-defined break in the surface 1 mm or more across, a well-defined back wall at the base of the depression, and an anechoic area within the plaque which extended to the surface and was 1 mm or more deep. Using these criteria, the two readers agreed on the diagnosis for 47 studies. When the surgical specimen was used as a reference standard, the accuracy of B-mode US was 60%, its sensitivity was 39%, and its specificity was 72%. Since the impact of scan quality was ruled out by using only scans on which the two readers agreed, the poor results must be attributed to the lack of definitive US criteria. A second review of the scans, with the readers looking only for a heterogeneous echo pattern, revealed that appearance had no higher correlation with ulceration at surgery than any of the original criteria had.

suMMARY The accuracy of a non-invasive ultrasound Doppler technique for the determination of the pressure gradient in mitral stenosis was evaluated in a study of 8 adult patients. Transseptal left atrial catheterisation and retrograde left ventricular catheterisation were performed. The same diastoles were used to compare the gradient constructed from the ultrasound data (APu) with that constructed from the manometric data (APM). In the 8 patients the difference between the mean diastolic values of APu and APM was -054 1'0 (SD) mmHg. The corresponding figure for mid-diastole was 0 01 ± 0 9 (SD) mmHg. The results indicate that the ultrasound technique is sufficiently accurate for diagnostic purposes.In an initial study of a non-invasive ultrasound Doppler technique for the determination of the pressure gradient in mitral stenosis (Holen et al., 1976) it was found that ultrasound can consistently register the frequency shifts from the diastolic mitral jet, and that the pressure gradient determined with ultrasound (APu,) agrees reasonably well with the manometric gradient (APM) obtained from the pulmonary capillary venous and left ventricular pressures. Subsequent ultrasound studies of more than 150 patients with mitral stenosis have reinforced this impression.