BACKGROUND AND OBJECTIVE: The anisotropy factor of light scattering (g) (wavelength 632.8 nm) in heated myocardium decreases as a function of temperature, suggesting, on the basis of Mie theory of light scattering, formation of an increasing number of particles with diameters smaller than the incident wavelength. STUDY DESIGN/ MATERIALS AND METHODS: To test this hypothesis, fresh myocardium was heated at constant temperatures between 37 degrees C and 75 degrees C for 1,000 s. Changes in size and number of granules generated by disintegrating organelles and sarcomeres were studied as a function of temperature by transmission electron microscopy, planimetry and particle counting. RESULTS: The mitochondria started to disintegrate at 45 degrees C and myofibrils between 45 degrees C and 50 degrees C into increasing numbers of small electron dense granules (diameter 50-200 nm), which correlated with the observed decrease of g from 0.93 +/- 0.02 (at room temperature to 45 degrees C) to 0.77 +/- 0.05 at 75 degrees C. CONCLUSION: The scattering coefficient microseconds of 161 +/- 33 cm-1 did not change significantly.
BACKGROUND AND OBJECTIVE: The anisotropy factor of light scattering (g) (wavelength 632.8 nm) in heated myocardium decreases as a function of temperature, suggesting, on the basis of Mie theory of light scattering, formation of an increasing number of particles with diameters smaller than the incident wavelength. STUDY DESIGN/ MATERIALS AND METHODS: To test this hypothesis, fresh myocardium was heated at constant temperatures between 37 degrees C and 75 degrees C for 1,000 s. Changes in size and number of granules generated by disintegrating organelles and sarcomeres were studied as a function of temperature by transmission electron microscopy, planimetry and particle counting. RESULTS: The mitochondria started to disintegrate at 45 degrees C and myofibrils between 45 degrees C and 50 degrees C into increasing numbers of small electron dense granules (diameter 50-200 nm), which correlated with the observed decrease of g from 0.93 +/- 0.02 (at room temperature to 45 degrees C) to 0.77 +/- 0.05 at 75 degrees C. CONCLUSION: The scattering coefficient microseconds of 161 +/- 33 cm-1 did not change significantly.
Authors: Stephanie A Eyerly; Tristram D Bahnson; Jason I Koontz; David P Bradway; Douglas M Dumont; Gregg E Trahey; Patrick D Wolf Journal: Heart Rhythm Date: 2012-07-03 Impact factor: 6.343
Authors: Stephanie A Eyerly; Tristram D Bahnson; Jason I Koontz; David P Bradway; Douglas M Dumont; Gregg E Trahey; Patrick D Wolf Journal: Ultrason Imaging Date: 2014-04 Impact factor: 1.578