This would avoid introducing inconsistencies between the content of the File Preamble and the remainder of the file content. In particular, if an FSU implementation needs to update the file content but is not able to recognize and fully process the content of the File Preamble (see Section 7.1), it may consider setting the first four bytes of the Preamble to 'DICM' followed by 124 bytes to 00H. The FSU is responsible for ensuring the internal consistency of the File and its conformance to PS3.10 and the specific SOP Class stored, exactly as if the FSU was creating a new File. If the content of a file needs to be updated or changed by an FSU, it is considered by this Part of the DICOM Standard as an M-DELETE Operation followed by an M-WRITE Operation. The non-support of such file update capabilities to the DICOMDIR File may simply result in having to delete and create a new file in order to keep the directory information consistent.

The DICOM File Service does not require that file update capabilities (e.g., append) be supported by every Media Format Definition selected. However it is assumed to be performed by the FS Creator. Media Preparation is outside the scope of this Part of the DICOM Standard.

Create dicomdir file