how to calculation Hounsfield unit

I want to calculate Hounsfield Unit of a CT image, Please provide me the syntax

[EVA Gallego Camuñas]

Hello Jhilam,

I also need to calculate Hounsfield Unit of an image. I have some grey images and their histograms and I need to relate the peaks of the histograms with the Hounsfield unit.

Did you find out how to calculate that? I would be very grateful if you could help me.

Thank you.

Answer 1

[Shawn Moyer]

Hounsfield units can be calculated using DICOM metadata:

Pixel value in Hounsfield units = m*SV+b

where:

Note that Hounsfield units are the default unit when tag (0028, 1054) is absent.

References:

<ftp://medical.nema.org/medical/dicom/final/cp519_ft.pdf> https://www.medicalconnections.co.uk/kb/Hounsfield_Units http://www.dicomtags.com/Iods/index/home/page:56 http://stackoverflow.com/questions/10193971/rescale-slope-and-rescale-intercept

[mohd akmal masud]

Just to confirm, the equation that you give, d is rescale intercept, and m is the rescale slope.

But according to your link given, https://www.medicalconnections.co.uk/kb/Hounsfield_Units, HU = m * P + b, its show that b is rescale slope and P is rescale intercept. its look like contradictory.

Which one true?

[Walter Roberson]

The site says,

"where: m is the Dicom attribute (0028,1053) "Rescale slope" b is the Dicom attribute (0028,1052) "Rescale intercept" P is the value of that particular pixel in the pixels array."

The only way that can be meaningfully understood is

"where: [m is the Dicom attribute number (0028,1053) whose name is "Rescale slope"] and [b is the Dicom attribute number (0028,1052) whose name is "Rescale intercept"] and [P is the value of that particular pixel in the pixels array]."