MECHANICAL IMAGING - A NEW TECHNOLOGY FOR MEDICAL DIAGNOSTICS

Mechanical imaging (MI) is a newly developed modality of medical diagn ostics based on reconstruction of tissue structure and viscoelastic pr operties using mechanical sensors. The essence of MI is the solution t o an inverse problem using the data of stress patterns on the surface of tissue compressed by a pressure sensor array. Imaged tissue structu res are presented in terms of their visoelastic properties. Evaluation of tissue 'hardness' (shear elasticity modulus) provides a means for characterizing the tissue, differentiating normal and diseased Conditi ons and detecting tumors and other lesions. In contrast to the other e xisting methods of medical imaging which use sophisticated hardware su ch as superconductive magnets, expensive X-ray equipment and complex u ltrasonic phased arrays, MI hardware consists of inexpensive mechanica l sensors and a positioning system connected to a PC. A key feature of MI is 'knowledge-based imaging'. To produce a three-dimensional image , the computer uses both the measured parameters of an individual exam ined object and a general database on anatomy and pathology of the obj ect. Two applications of MI are currently being developed: MI for mass screening and detection of breast cancer and MI for imaging the prost ate and diagnosing prostate diseases. ii prototype of the device for m echanical imaging of the prostate has been developed and is being test ed clinically at the Robert Wood Johnson Medical School, New Jersey. T he device is comprised of a transrectal probe with a position sensor a nd a pressure sensor array mounted on the articulated rip, an electron ic unit and a PC. Results of extensive laboratory studies with rubber prostate models and initial data obtained in clinical trials strongly suggests that for certain applications the MI technology, as a new mod ality of imaging, has a diagnostic potential comparable to that of con ventional diagnostic technologies. Mechanical imaging of the prostate appeared to be an efficient means of objectively evaluating and imagin g the prostate and detecting prostate cancer. (C) 1998 Elsevier Scienc e Ireland Ltd. All rights reserved.