Surgical Retained Foreign Objects (RFOs) cause significant morbidity and mortality. They are associated with $1.5 billion annually in preventable medical costs. The detection accuracy of radiographs for RFOs is a mediocre 59%. We address the RFO problem with two complementary technologies: a three dimensional (3D) Gossypiboma Micro Tag (μTa) that improves the visibility of RFOs on radiographs, and a Computer Aided Detection (CAD) system that detects the μTag. The 3D geometry of the μTag produces a similar 2D depiction on radiographs regardless of its orientation in the human body and ensures accurate detection by a radiologist and the CAD. We create a database of cadaveric radiographs with the μTag and other common man-made objects positioned randomly. We develop the CAD modules that include preprocessing, μTag enhancement, labeling, segmentation, feature analysis, classification and detection. The CAD can operate in a high specificity mode for the surgeon to allow for seamless workflow integration and function as a first reader. The CAD can also operate in a high sensitivity mode for the radiologist to ensure accurate detection. On a data set of 346 cadaveric radiographs, the CAD system performed at a high specificity (85.5% sensitivity, 0.02 FPs/image) for the OR and a high sensitivity (96% sensitivity, 0.73 FPs/image) for the radiologists.
Gossypibomas are foreign objects, usually surgical sponges or towels, accidentally retained in the human
body during an operation. They are associated with significant postsurgical complications, morbidity and
mortality. Postsurgical radiographs are considered the standard of care for a retained foreign body, but their
detection sensitivity typically ranges between 60% and 80%. To address this we have microfabricated x-ray
visible microtags that can be attached to foreign bodies and allow them to be easily recognized by a trained
radiologist or a computer aided detection (CAD) algorithm. Key element of the microtag design is the use of
three radiopaque beads placed in a precise, triangular configuration. We demonstrated that those microtags
are visible in standard radiographs over different backgrounds (soft tissue, bone) and at different spatial
orientations. We envision that these microtags attached to surgical sponges and towels will greatly increase
the detection sensitivity and specificity of gossypibomas at an infinitesimal cost and will be used in the
operating room to provide point of care information to the surgeons.