There are a couple ways to determine the number of slices in a mosaic. Easiest would be to open the dicom image in a viewer and count. Another way is to look at the Acquisition Number (0020|0012) and Instance Number (0020|0013) in the dicom header. If you open up a dicom image and extract those numbers, you'll see that

InstanceNumber = (AquisitionNumber-1)*numSlices + 1


numSlices = (InstanceNumber - 1)/(AcquisitionNumber - 1)

Of course, this will only work with images other than the first one.

This image viewer has a nice dicom header explorer in it:

Hope this helps!

Wen-Ching Liu wrote:
[log in to unmask]" type="cite">Dear All:

Our Siemens MR system has been upgraded and I found the
image format for MOSAIC is different now.  Does anyone know
how to read the DICOM tag "Number of Images in Mosaic" or
something similar which can tell me how many slices in the

This question may be too technique, sorry about that.
I have problems to find the answer.

Thanks in advance.

Wen-Ching Liu, Ph.D.

Assistant Professor
Functional Imaging Laboratory
Department of Radiology
University of Medicine and Dentistry
of New Jersey-New Jersey Medical School

973-972-2281/fax: 973-972-0836