RadiAnt DICOM Viewer - Discussion Forum
Number Of Phase Encoding Steps

Dec 26, 2019 07:37 PM
by Apple
Below is from DICOM header of a MRI image:
NumberOfPhaseEncodingSteps: 420
EchoTrainLength: 15
PercentSampling: 70
PercentPhaseFieldOfView: 100
PixelBandwidth: 250
AcquisitionMatrix: [0 320 224 0]
InPlanePhaseEncodingDirection: 'ROW'
Private_0019_10xx_Creator: 'SIEMENS MR HEADER'
Rows: 320
Columns: 320
PixelSpacing: [0.6875 0.6875]
Acquisition: 224 * 320
FieldOfView: 220 * 220

How to match the NumberOfPhaseEncodingSteps: 420 with all other parameters?

Thanks.

Apple
Dec 28, 2019 02:03 PM
by RadiAnt
NumberOfPhaseEncodingSteps: total number of lines in k-space in the 'y' direction collected during acquisition.
Feb 6, 2020 05:30 PM
by VetMed
Basically you will have to ask Siemens for the details. A little help I can give: Rows and Columns are the image reconstruction matrix (how the pixels are displayed on your monitor), whereas "Acquisition" is the true acquisition matrix. Usually the smaller value is the phase encoding part. But you also have only 70 Percent Sampling, which would give you an actual (true) acquisition matrix of only 157 (156.8 calculated 70 % of 224). Only way I see how you can have 420 phase encoding steps like that is via activated oversampling. That would increase the number of phase encoding steps outside of your FOV.
But again - Siemens might calculate that differently.
Best,
VetMed
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