Exclude trace volume from Philips DICOM?

[mgxd]

Originally brought up in nipy/heudiconv#275 by @bmelo

Version: nibabel-2.3.1

Loading up a Philips diffusion DICOM (with trace volume) results in an incorrect image shape with an extra? dimension (96, 96, 60, 2, 33).

In [1]: from nibabel.nicom.dicomwrappers import wrapper_from_file

In [2]: mw = wrapper_from_file('philips-dwi.dcm', force=True)

In [3]: mw.image_shape
---------------------------------------------------------------------------
WrapperError                              Traceback (most recent call last)
<ipython-input-3-4963e90423f3> in <module>()
----> 1 mw.image_shape

/home/mathias/miniconda2/envs/dev3/lib/python3.6/site-packages/nibabel/onetime.py in __get__(self, obj, type)
    139         # Errors in the following line are errors in setting a
    140         # OneTimeProperty
--> 141         val = self.getter(obj)
    142 
    143         setattr(obj, self.name, val)

/home/mathias/miniconda2/envs/dev3/lib/python3.6/site-packages/nibabel/nicom/dicomwrappers.py in image_shape(self)
    535         n_vols = np.prod(shape[3:])
    536         if n_frames != n_vols * shape[2]:
--> 537             raise WrapperError("Calculated shape does not match number of "
    538                                "frames.")
    539         return tuple(shape)

WrapperError: Calculated shape does not match number of frames.