Digital subtraction arthrography
This method uses digital subtraction techniques taken from the field of angiography, and requires expensive specialized equipment. It involves injection of contrast into the joint, while keeping the arm still, and taking images at 1 second intervals. The images are then subtracted by a computer from a mask image without contrast, in order to obtain bone-free images. Enthusiasts claim that it is more sensitive in detecting full thickness and deep surface tears, and can show the site and size of a tear more accurately than the conventional technique. It can also be used to evaluate shoulder replacements for loosening. It is technically more difficult than conventional arthrography, and has not found wide application.