Biomedical subjects

J R Domnanovich

Publications and source records attributed to J R Domnanovich.

3 recordsLinked to original sources

PubMed1992

A new heart-sounds gating device for medical imaging.

A heart-sounds gating device has been designed and tested which identifies, individually, both the first (S1) and second (S2) heart sound from their timing relationship, providing two trigger points through the cardiac cycle for synchronizing medical images. The new heart-sounds gate utilizes dynamically varying timing windows to anticipate the occurrence of S1 and S2. The heart-sounds gate has been initially applied to nuclear imaging of the cardiac bloodpool, but may be applied to any imaging modality requiring cardiac synchronization.

Electrocardiography↗

PubMed1991

Multigated blood-pool imaging using heart sounds.

A method to trigger multigated blood-pool (MGBP) acquisition using both the first and second heart sound has been developed. The heart sound gating (HSG) circuitry identifies, individually, both the first (S1) and second (S2) heart sounds from their timing relationship alone, and provides two trigger points during the cardiac cycle. First heart sound gating may be performed to assess the systolic ejection portion of the cardiac cycle, with S2 gating utilized for reproduction of the diastolic filling portion of the cycle. Heart sound gating has been applied to twenty patients who underwent analysis of left ventricular function, and compared to conventional ECG-gated MGBP. Left ventricular ejection fractions calculated from MGBP studies using a first and a second heart sound trigger correlated well with conventional ECG gated acquisitions in patients adequately gated by HSG and ECG. Heart sound gating may be utilized in patients with rapidly changing heart rates, as S1 and S2 precisely define end-diastole and end-systole, respectively, and in situations when the ECG is inadequate for gating purposes.

Electrocardiography↗

PubMed1985

Dual-isotope motion correction technique for gated exercise scintigraphy.

In exercise multigated blood-pool imaging, significant degradation of image quality occurs as a result of patient movement under the gamma camera. Motion correction devices using centroid tracking of x-y events emanating from the organ of interest cannot be applied to blood-pool studies, because cardiac contraction and rotation masks the correctable patient motion component. We have developed a dual-isotope motion correction technique (DIMC) which utilizes a second point source of dissimilar energy (241Am) to monitor movement. Positional centroids from events incident in the 241Am window are used to develop correction coordinates which are applied to the 99mTc blood-pool events. The ability of DIMC to reduce blur due to motion has been evaluated qualitatively with phantoms and quantitatively by using spatial resolution measurements obtained from stationary line sources and from sources moving at varying rates. Based on these criteria, we have found the device to be capable of reducing over 90% of the image blur of objects moving at 5.1 cm per sec. In preliminary gated exercise studies, subjective perception of image quality was shown to be significantly improved in the DIMC corrected image, when compared to images obtained without DIMC. Improvement in image quality for exercise gated studies is of particular importance because of the low count density obtained during these procedures.

Americium↗