[Insight-users] Measuring tumor diameter

[Somer, Edward]

Hi,

Having segmented the tumour I'd try a 3D-distance transform to find the 
interior pixel furthest from any edge of the mask. Isn't the maximum 
diameter then twice the value of the distance transform at this point?

Perhaps I'm missing something,

Ed

Andriy Fedorov wrote:
> Luis,
>
> I am actually looking for an automatic tool.
>
> The approach I am currently considering is this:
>
> 1) go through the axial slices, find the one with the largest area
> 2) extract that slice contour
> 3) go through all possible combinations of the contour points, find
> the pair of most distant points, and take this as a diameter
> 4) follow the line between the points in the previous step, and
> subtract the parts of the line that are outside the contour (this is
> how the tumor measurements are actually taken). This may change the
> measured diameter.
> 5) repeat steps 3 and 4 until the maximum is found after taking into
> account diameter parts outside the countour
>
> The problem of course is that this procedure will be quadratic to the
> number of contour points, and I am looking for ways to speed this up,
> or find an existing implementation, or find a better way to find the
> farthest point. I thought about kd-tree to optimize point location,
> but I am not sure how to use it for farthest point.
>
> Any comments are welcome
>
> Andriy Fedorov
>
>
> On Thu, Dec 11, 2008 at 9:47 AM, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>   
>> Hi Andi,
>>
>>
>> Are you looking for an automatic tool ?
>> or for an interactive method ?
>>
>> In VTK you will find 3D Widgets designed
>> for taking measurements in-plane.
>>
>>
>>  Regards,
>>
>>
>>     Luis
>>
>>
>> ------------------------
>> Andriy Fedorov wrote:
>>     
>>> Hi,
>>>
>>> I need to measure the longest diameter of a 3D tumor segmentation. I
>>> was wondering, if anybody is aware of any existing tools for this
>>> purpose? If not, are there tools to quickly measure the diameter of a
>>> 2D projection of the segmentation?
>>>
>>> I just wanted to have the community opinion before starting to
>>> implement something myself.
>>>
>>> Andriy Fedorov
>>> _______________________________________________
>>> Insight-users mailing list
>>> Insight-users at itk.org
>>> http://www.itk.org/mailman/listinfo/insight-users
>>>
>>>       
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
>   


-- 
Edward Somer, PhD.
Senior PET Methodologist
The PET Imaging Centre 
St Thomas' Hospital
London, UK
SE1 7EH

work tel: +44 (0) 20 7188 1497
work fax: +44 (0) 20 7620 0790
e-mail: Edward.Somer at kcl.ac.uk / Edward.Somer at googlemail.com