<qa>  What is the blood clot lodged in a lung artery?The study will use imaging data, demographic information, and other medical information from the medical charts of Clinical Center patients to test and evaluate new CAD applications. Such applications include detection of subcutaneous under the skin lesions in melanoma patients, bone lesions in patients with advanced cancer, and pulmonary emboli blood clot lodged in a lung artery in patients who are known to have pulmonary emboli, and other uses. 