Biomedical subjects

O T Von Ramm

Publications and source records attributed to O T Von Ramm.

4 recordsLinked to original sources

PubMed1998

3D ultrasound tissue motion tracking using correlation search.

Several methods for ultrasound tissue motion tracking and blood velocity estimation have been proposed and clinically applied. While providing valuable information to the clinician that was not obtainable from B-mode anatomical imaging, these methods still suffer from various fundamental and practical limitations that compromise their performance in certain clinical situations. A significant limitation is the inability of most of these methods to estimate the complete 3D motion or velocity vectors. With the introduction of ultrasound volumetric imaging, the need for a method that is capable of obtaining the complete motion vector is even more pressing. In this paper, we investigate the implementation of a correlation search scheme to estimate the 3D motion vectors using successive volumetric ultrasound scans. We present tracking results for motion along different axes and discuss the advantages and limitations of performing the correlation search in 3D.

Algorithms↗

PubMed1995

Feasibility study for a two-dimensional diagnostic ultrasound velocity mapping system.

A receive beam-tracking technique is introduced for simultaneously measuring more than one dimension of an existing velocity vector in medical ultrasound. By using flexible beamforming and a conventional linear-array transducer, vectors can be measured at real-time frame rates over a significant field of view. Both simulations and in vitro experiments show that this technique should provide more accurate measurements of blood flow velocities in the human body than is available with current color flow mapping systems.

Blood Flow Velocity↗

PubMed1978

Principles and applications of a dynamically focused phased array real time ultrasound system.

The physical principles and clinical applications of a high-resolution, dynamically focused phased-array real time ultrasound are described. Advantages of the real time technique include rapid survey capability, efficient selection of an appropriate tomographic plane, identification of pulsating structures, and dynamic studies. The capabilities of a high resolution phased array with extended dynamic focusing to a range of 15-20 cm are demonstrated in vascular, abdominal, and obstetric imaging. Appropriate clinical examples showing normal and pathological anatomy are presented. Comparisons with conventional B scans are illustrated.

Abdomen↗

PubMed1976

Echocardiographic evaluation of tricuspid valve endocarditis: an M mode and two dimensional study.

Standard M mode echocardiography and a new real time two dimensional echocardiographic imaging system were utilized to follow the progressive anatomic destruction of the tricuspid valve in a patient with bacterial endocarditis. The initial two dimensional echocardiographic study revealed large vegetative masses attached to severely prolapsing tricuspid leaflets. Serial studies demonstrated eventual disruption of the chordal attachments of the anterior tricuspid leaflet resulting in frank leaflet flail. This technique was seen to complement both M mode echocardiography and cardiac angiography by providing spatial information concerning serial changes in the disordered tricuspid valve. Such findings call attention to the relative roles of various diagnostic measures, including M mode and two dimensional echocardiography, in assessing the specific anatomic and functional performance of a diseased tricuspid valve.

Adult↗