Myocardial Oxygenation in Dogs During Reactive Hyperemia

Parsons, William J.; Rembert, Judith C.; Bauman, Robert P.; Greenfield, Joseph C.; Piantadosi, Claude A.

doi:10.1117/1.429875

Cited by 5 publications

(1 citation statement)

References 40 publications

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“…Although a small blood flow contribution may still exist (DERUMEAUX et al, 1998;PARSONS et al, 1998), for example from collateral blood vessels, the LDPM signal is expected to be almost entirely generated by tissue motion. Low-velocity intervals (TDIi,t), at the end of the occlusions, were always found late in systole.…”

Section: Discussionmentioning

confidence: 99%

Myocardial tissue motion influence on laser Doppler perfusion monitoring using tissue Doppler imaging

Karlsson

Hübbert

Lönn

et al. 2004

Med. Biol. Eng. Comput.

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Tissue motion of the beating heart generates large movement artifacts in the laser Doppler perfusion monitoring (LDPM) signal. The aim of the study was to use tissue Doppler imaging (TDI) to localise intervals during the cardiac cycle where the influence of movement artifacts on the LDPM signal is minimum. TDI velocities and LDPM signals were investigated on three calves, for normal heartbeat and during occlusion of the left anterior descending coronary artery. Intervals of low tissue velocity (TDIint, < 1 cm s(-1)) during the cardiac cycle were identified. During occlusion, these intervals were compared with low LDPM signal intervals (LDPMint, <50% compared with baseline). Low-velocity intervals were found in late systole (normal and occlusion) and late diastole (normal). Systolic intervals were longer and less sensitive to heart rate variation compared with diastolic ones. The overlap between LDPMint and TDIint in relation to TDIint length was 84+/-27% (n = 14). The LDPM signal was significantly (p < 0.001, n = 14) lower during occlusion if calculated during minimum tissue motion (inside TDIint), compared with averaging over the entire cardiac cycle without taking tissue motion into consideration. In conclusion, movement artifacts are reduced if the LDPM signal is correlated to the ECG and investigated during minimum wall motion. The optimum interval depends on the application; late systole and late diastole can be used.

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Section: Discussionmentioning

confidence: 99%

Myocardial tissue motion influence on laser Doppler perfusion monitoring using tissue Doppler imaging

Karlsson

Hübbert

Lönn

et al. 2004

Med. Biol. Eng. Comput.

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Applications of Near‐Infrared Spectroscopy in Medical Sciences

Heise¹

2001

Near‐Infrared Spectroscopy

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Near-infrared spectroscopy has found many applications, which are described in part in other chapters of this book. For chemical quality and process control, nearinfrared spectroscopy has received much attention because of its speed and attribute of requiring little or no sample preparation. Fast measurement equipment and techniques have been established within the pharmaceutical industry for the identification of raw materials on receipt, as well as for verifying the composition of pharmaceutical formulations before the final products leave the premises. Within the life sciences arena, several standard methods for food analysis have been accepted by a number of different associations, even as early as in the 1980s, one example being the determination of protein and moisture in cereals. Other applications are concerned with the analysis of meat and fish, for example, for the determination of fat, protein etc., whereas convenient analyses of beer and other alcoholic beverages are carried out by transmission spectroscopy. The authentication of food and food ingredients is another field in which near-infrared spectroscopy has been successfully applied.The relatively late emergence of near-infrared spectroscopy into the medical field is mainly due to the complexity of the samples under investigation, analytes of low concentrations and problems associated with the intense absorptions of water, usually the major constituent of biomedical samples and, in particular, of biofluids. Therefore, it was of great importance to have good reproducibility for the recording of spectra and a high signal-to-noise ratio, which could be accomplished by using Fourier-transform spectrometers. Clinical chemistry has profited from recent improvements in instrumentation, and the successful near-infrared spectroscopic analysis of human blood plasma for a number of important analytes has marked the beginning of a new era [l].The rationale behind medical diagnosis by spectroscopy was substantiated by Mantsch and co-workers through the fact that diseases are accompanied by changes in the biochemistry of the cells and tissues that make up the different organs in our body. Since the infrared spectroscopic technique can provide information on biological molecules like proteins and peptides, chromophores and chro-Near-In frared Spectroscopy : Principles, Instruments, Applications

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Improved model for myocardial diffuse reflectance spectra by including mitochondrial cytochrome aa3, methemoglobin, and inhomogenously distributed RBC

Lindbergh¹,

Häggblad²,

Ahn³

et al. 2011

Journal of Biophotonics

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The aim of this study was to compare a previously used light transport model (I) comprising the chromophores hemo- and myoglobin, fat, and water, with two extended models, where the chromophores of cytochrome aa3, methemo- and metmyoglobin are added (model II), and in addition, accounting for an inhomogenous hemoglobin distribution (model III). The models were evaluated using calibrated diffuse reflectance spectroscopy measurements on the human myocardium. Model II proved a significantly better spectral fitting, especially in the wavelength ranges corresponding to prominent absorption characteristics for the added chromophores. Model III was significantly better than model II and displayed a markedly higher tissue fraction and saturation of hemo- and myoglobin. The estimated tissue chromophore fractions, saturation and oxidation levels, were in agreement with other studies, demonstrating the potential of diffuse reflectance spectroscopy measurements for evaluating open heart surgery. However, the choice of chromophores and vessel packaging effects in the light transport model has a major effect on the results.

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Myocardial Oxygenation in Dogs During Reactive Hyperemia

Cited by 5 publications

References 40 publications

Myocardial tissue motion influence on laser Doppler perfusion monitoring using tissue Doppler imaging

Myocardial tissue motion influence on laser Doppler perfusion monitoring using tissue Doppler imaging

Applications of Near‐Infrared Spectroscopy in Medical Sciences

Improved model for myocardial diffuse reflectance spectra by including mitochondrial cytochrome aa3, methemoglobin, and inhomogenously distributed RBC

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