This question is underspecified. It soulds like you have enhanced DICOM data, which suggests you have a Canon, Philips or Siemens XA scanner - so the question is which one? My first guess is this is a system running the emergent Siemens XA, and you will need to get the development build of dcm2niix to support the new features. You can get it by going here
  https://ci.appveyor.com/project/neurolabusc/dcm2niix
selecting your operating system (windows, Linux or MacOS) and downloading the artifact. This new development version will being report v1.0.20230320


Alternatively, you can run fslmerge.