Explicit Versus Implicit VR Attributes

DICOM attributes provide the length and then the data. When writing data to a file, you can include a two-letter value representation (VR) with the attribute or you can let DICOM infer the value representation from the data dictionary. When you specify the VR option with the value 'explicit', the dicomwrite function includes the VR in the attribute. The following figure shows the attributes with and without the VR.