Improvement of Lesion Detection by Echographic Image Processing

The texture of echographic images of scattering media is characterized by speckle. The phenomenon of speckle formation is due to the relatively narrow bandwidth of the transmitted ultrasound pulses and the constructive and destructive interference of echoes backscattered by a volume of tissue which occurs on the surface of the receiving transducer’. The presence of speckle, causing a mottled or granular echographic image, degrades the apparent resolution in the images and it interferes with the visual assessment of small contrasts in grey level or in texture. However, changes in mean grey level and in texture pattern indicate diffuse parenchymal diseases or focal lesions (e.g., metastatic tumours) within an organ. Therefore, early detection of these changes is of great clinical importance.