Non-invasive assessment of temperature variation in Ex-vivo renal tissue by tracking average grey-level from B-mode images

The average grey-levels (AVGL) calculated from B-Mode images were assessed for non-invasive temperature estimation in a porcine kidney sample. The porcine kidney was subjected to heating and cooling procedure with temperature varying from 36°C to 45°C. The sample was continuously imaged with an ultrasound scanner, and simultaneously temperature was measured at each 5 s using two Type-T thermocouples placed at the central region and at the bottom of the sample. The result shows that AVGL/Temperature relations were highly correlated for both regions, and considering heating and cooling periods. Besides, AVGL/Temperature functions estimated fitting errors inferior to ± 0.25°C, indicating that it might be possible to track temperature changes from both tissues using AVGL. This result is innovative since it suggests that AVGL seems to be robust to estimate non-invasively temperature variations in B-mode images from tissues presenting a complex morphological structure.