Posted by
Salim Kanoun on
Feb 26, 2017; 7:40am
URL: http://imagej.273.s1.nabble.com/Problems-in-reading-Hounsfield-units-from-a-DICOM-image-Fiji-tp5018195p5018197.html
Hi Shreya,
I never seen that.
Depending on the manufacturer there is a high range of possible rescale
slope/intercept.
However imageJ always recover the correct UH for each CT I have seen.
Maybe your Dicom are corrupted ? Can you share with us a sample of the
original dicom file ?
Best regards
Salim
Le 26 févr. 2017 06:24, "Shreyakanakiya" <
[hidden email]> a écrit :
Hello,
I have a set of DICOM images. When I import them as an image sequence I
believe that Fiji reads the slope and intercept from the DICOM header and
converts the raw pixel values to Hounsfield units (HU). In my header file,
however, the rescale slope = 1 and rescale intercept = 0. Thus by the
formula,
Hounsfield unit = pixel value*slope+intercept
My Hounsfield units are the same as pixel values. I want to segment the
image using the Hounsfield scale (air = -1000 HU, water = 0 HU). But since
all my values are positive I am unable to use it directly. I have attached a
histogram of my DICOM image stack for reference. The left peak represents
the background (air) and the right peak represents the grayscale
distribution of my data (rock).
I'm not aware of a calibration to have only positive HU but am new to this
field and wanted to know if such a calibration exists ? If yes, is there a
way I can rescale them such that air = -1000 HU, water = 0 HU and so on?
Thanks in advance.
-Shreya
<
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