wrong conversion of dicom-files

[Lyuba]

ImageMagick
DICOM-files (grayscale, 16 bits) are identified as 8-bits:
  identify test.dcm
  test.dcm DCM 512x512 512x512+0+0 8-bit DirectClass

and convert gives wrong picture for such files:
  convert test.dcm test.jpeg
additional parameters don't help:
  convert -depth 16 -type grayscale test.dcm test.jpeg

Version: ImageMagick 6.7.7-10 2014-03-06 Q16 http://www.imagemagick.org

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=14.04
DISTRIB_CODENAME=trusty
DISTRIB_DESCRIPTION="Ubuntu 14.04.2 LTS"

imagemagick:
  Installed: 8:6.7.7.10-6ubuntu3
  Candidate: 8:6.7.7.10-6ubuntu3
  Version table:
 *** 8:6.7.7.10-6ubuntu3 0
        500 http://archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status