Checking the Image Acquisition Protocol

DCE-CT/MR scanners use multidetectors to simultaneously capture multiple slices of images.  The DCE Tool automatically detects the number of CT/MR slices (or detectors) used to capture these images from the DICOM headers called "SliceLocation".  The time protocol (or the frequency of image acquisition) used for imaging is determined from the DICOM header called "AcquisitionTime".

However, if the time protocol is incorrectly entered or the DICOM headers are generated incorrectly, the DCE Tool will either recognize an incorrect time protocol or assume that the images were acquired at a frequency of 1 image per second.  Therefore, it is important to check the parameters on the Time Protocol Settings tab before proceeding.  The information presented in the Scan Time Protocol table is based on the cumulative number of slices acquired.

To verify the information in the Time Protocol Settings:

      1.  Verify the information in the Number of Slices Per Volume text box.
      2.  Verify the information in the Scan Time Protocol table (see below).


How is the Scan Time Protocol table read?

From slice 1 to slice 240, the images were acquired every second.
From slice 240 to slice 242, the images were acquired every 8 seconds.
From slice 242 to slice 256, the images were acquired every 15 seconds.

In other words, this is a study that contains a continuous phase (1st to 240th slices) and a discontinuous phase (242nd to 256th slices).  The inter-scan delay is 8 seconds (240th to 242nd slices).

The time protocol settings can also be visualized in the Time Protocol Display graph. 

To change the information in the Time Protocol Settings tab:

      1.  Directly change the numbers in the Sec column if all other information presented is correct, or
      2.  Click the Remove button to remove the row(s) with incorrect information
      3.  Then enter the correct information in the Time Series and Scan Time Interval text boxes.
      4.  Click Add to update the table.
      5.  Click Confirm Time Protocol and Continue once the information presented is correct to proceed to
           the Contrast Uptake tab (or Intensity Uptake if it is a DCE-MR series).