The E-R Model in Section A.1.2 depicts those components of the DICOM Application Information Model that directly reference the X-Ray Angiographic Image IOD, with exception of the Frame of Reference and Modality LUT entities, which are not used. Additionally, "Image" in Figure A.1-1 may represent a single-frame or a multi-frame image. A frame denotes a two-dimensional organization of pixels recorded as a single exposure.