/// \brief returns the Fourth field of the current gdcmDictEntry
/// \warning NOT part of the Dicom Standard.
/// May be REMOVED an any time. NEVER use it.
/// @return The Fourth field
/// \brief returns the Fourth field of the current gdcmDictEntry
/// \warning NOT part of the Dicom Standard.
/// May be REMOVED an any time. NEVER use it.
/// @return The Fourth field