Multiplicative optical tomography of cardiac electrical activity.
Cardiac electrical activity can be mapped today through the response of voltage-sensitive dyes; but poor transparency of muscle tissue has enforced shallow-depth imaging. We present a three-dimensional (3D) reconstruction method for electrical activity deep inside the myocardial wall. Our approach is nonlinear and differs substantially from standard diffusive optical tomography. It does not require matrix inversion, data regularization or a priori information concerning the original object. Opposite sides of a slab-shaped preparation are scanned in parallel by detection and illumination points with a constant vector offset between illumination and detection axes (biaxial scanning). Scanning is performed in two perpendicular directions. In each direction, a pair of 2D images is obtained under offsets of opposite signs. These two pairs are the input for a multiplicative reconstruction algorithm, whose output is a 3D image. The overall procedure was successfully tested on computer-generated sources that include points, lines and hemispheres, patterned after actual electrophysiological excitations. The algorithm is computationally efficient and stable with respect to varying noise levels in the raw data.
Wellner
Marcel
M
Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA. wellnerm@upstate.edu
Bernus
Olivier
O
Mironov
Sergey F
SF
Pertsov
Arkady M
AM
D000465:Algorithms; D004594:Electrophysiology; D006329:Heart Conduction System / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D009206:Myocardium / Q000473:pathology*; D011856:Radiographic Image Enhancement / Q000379:methods*; D041622:Tomography, Optical / Q000379:methods*