I just pushed my changes to ImageMagick and I can read your image perfectly now. This will be resolved in the next version of Magick.NET. If you want to get the DICOM information you should use the
GetAttribute method of MagickImage. For the name of patient you should use "dcm:Patient'sName" and with "dcm:StudyDate" you can get the study date. A lot more are available in your file. You get get all their names with the AttributeNames property.