A disposable bag for maintaining sterility of a medical instrument having a detection mechanism and cable extending from the detection mechanism,wherein the bag comprises:a pair of flexible sheets comprised of a polymeric material,the pair of sheets being arranged in parallel to each other and sealed along opposing lateral sides that extend longitudinally from a top end to a bottom end,the cable having a selected length such that upon insertion of the detection mechanism through the enclosed interior chamber of the bag, the cable extends longitudinally through the open bottom end,the bag being adapted to be attached to at least a portion of the cable that extends from the detection mechanism downstream toward the open bottom end.