Biomedical subjects

O von Ramm

Publications and source records attributed to O von Ramm.

5 recordsLinked to original sources

PubMed2000

Real-time volumetric echocardiography: the technology and the possibilities.

The heart is a dynamic organ with complexities in its shape. As such, it places special demands on three-dimensional techniques for reconstruction. Real-time volumetric echocardiography, which is based on phased array and parallel processing principles to enhance line density within a scan volume, provides rapid image acquisition. We introduce the principle, potential clinical importance, current limitations, and future of volumetric imaging methods.

Echocardiography, Three-Dimensional↗

PubMed1991

Real-time, three-dimensional echocardiography: feasibility and initial use.

The purpose of this article is to review new approaches to three-dimensional acquisition and presentation of echocardiographic data. New three-dimensional phased-array devices hold great promise for the development and application of new descriptors for left ventricular performance, myocardial perfusion, and other important indices of cardiac function.

Echocardiography↗

PubMed1986

Real-time orthogonal mode scanning of the heart. I. System design.

A necessary percursor to real-time three-dimensional echocardiographic imaging is the ability to obtain multiple planes of acoustic data simultaneously. A new ultrasound imaging technique facilitates the display of two real-time orthogonal B-mode images (O-mode). The O-mode technique uses a novel two-dimensional transducer and system processor to interrogate the two perpendicular planes simultaneously, yielding sector arcs that share one origin. It permits simultaneous display of two sector arcs on a single monitor either side by side or in a two-dimensional projection designed to convey the three-dimensional nature of the acoustic data. Clinical results from the first 50 patients undergoing O-mode evaluation indicate that image quality in the two simultaneously obtained planes is equal to that of a single plane when the system is operating in its conventional format. These data confirm the feasibility of real-time multiplane imaging. The system design offers the potential for the future addition of more simultaneous planes and, thus, the possibility of real-time three-dimensional ultrasound imaging.

Adult↗

PubMed1981

Combined doppler and phased-array echocardiographic estimation of cardiac output.

The capability of a pulsed Doppler flowmeter combined with a phased-array imaging system to measure volume flow was tested in vitro and in patients undergoing cardiac catheterization. The Doppler-phased-array system (DPA) was used to determine vessel diameter and a superimposed cursor was used to locate the range and angle of the Doppler sample volume. DPA estimates of continuous flow through tubing in a water tank correlated strongly (r = 0.99) with measured flow corresponding to physiologic ranges from 3-12 l/min. For pulsatile flow in a water tank, a correlation of r = 0.86 with measured flow was obtained, whereas DPA estimates of cardiac outputs compared with Fick estimates in the 11 patients produced a correlation of r = 0.83. These data indicate that estimates of cardiac output are possible using the DPA approach.

Adult↗

PubMed1977

A comparison of real-time, two dimensional echocardiography and cineangiography in detecting left ventricular asynergy.

Left ventricular wall motion was assessed in 105 consecutive patients both invasively, using biplane cineangiography, and noninvasively, by a real-time, phased-array, two-dimensional echocardiography system. Ventricular wall motion in five anatomic areas of the ventricle (anterolateral, posterolateral, apical, septal, and inferior) was analyzed by both methods in a double-blind manner. Two-dimensional echocardiographic images were deemed adequate for analysis in 82% of the regions (430 of 525). Fifty-five discrepancies were noted in the comparison of the remaining 430 regions. The reasons for discrepancies in interpretation between the two methods were established for 54 during retrospective review: 33 were due to echocardiography (inadequate target visualization, observer error, or tangential echo views). Fifteen were related to angiography (overlay of silhouettes or observer error), and six were due to other reasons including definition problems or spatial orientation difficulties. Both real-time, two-dimensional echocardiography and cineangiography have advantages and disadvantages. The techniques used together could provide more complete information concerning ventricular wall movement than is now currently available.

Cineangiography↗