Importing and Calibrating CT or MR Images

Preparing the image files

The recommended method of preparing CT and MR multiplanar reconstructions (MPR) for Plaque Simulator is to use the OsiriX program to create the images and export them as .jpg files. You should create a folder for each new patient and organize all of the support files for the patient in their folder. If you follow the PS6 naming conventions for image files (i.e. files with extensions .jpg, .png, .tif and so on), you can load all of your images with a single click and file navigation procedure.

The PS6 naming conventions for image files are:

  • The substring "axial" is reserved for the axial MPR image (case insensitive, e.g. some permissible names are axial, Axial, axialxxxx, xxxxaxial).
  • The substring "sagit" is reserved for the sagittal MPR image (case insensitive, e.g. some permissible names are sagit, Sagit, sagittal, Sagittal).
  • The substring "equat" is reserved for the coronal image at the equator (case insensitive, e.g. some permissible names are equat, Equator, Equatorial).
  • The substring "mer" is reserved for the tumor-meridian MPR image (case insensitive, e.g. some permissible names are t-mer, T-Mer, t-meridian, T-Meridian).
  • The substring "cor" is reserved for the tumor-coronal MPR image (case insensitive, e.g. some permissible names are t-cor, T-Cor, t-coronal, T-Coronal).
  • The substring "US2" is reserved for ultrasound image #2 (case sensitive, e.g. some permissible names are US2, US2image, xxxUS2).
  • The substring "US" is reserved for ultrasound image #1 (case sensitive, e.g. some permissible names are US, US1, USimage, US1image, xxxUS, xxxUS1).
  • The substring "fund" is reserved for the fundus collage (case insensitive, e.g. some permissible names are fund, fundus and Fundus but not FUNDUS since the upper case pair US is reserved for ultrasound images).
  • The substring "eyepic" is reserved for a frontal picture of the eye (case insensitive, e.g. some permissible names are eyepic, eyepicture, EyePic, EyePicture).

For example, if the name of the patient is Mr. Posterior Tutorial, create a folder named "Posterior Tutorial" and put all of the images associated with that patient into his folder. If you have additional image files that include any of the reserved substrings put them in a folder whose name is enclosed in (), otherwise they will interfere with the multiple file loading process.

NOTE: Image widths and heights should be at least a few hundred pixels, but not greater than about 1000 pixels. As image dimensions increase, memory usage during planning increases, image processing slows, and the resulting file sizes for .iplan and printing to .pdf increase. File sizes greater than about 10MB complicate electronic transfer. If you intend to email .pdf files to colleagues for review, you may need to apply image resolution filters to your .pdf files before emailing.

ExamplePatientFolder

In Plaque Simulator's Image window
  • If the Image window is not visible, bring it to the front by selecting the Images item from the Window menu.
    WindowImages
ImageWindowAtStartup

Opening image files

In the Image window:

To open a single image, first select an image buffer by clicking the button for that image. For example, to open the axial MPR, click the button labeled Axial. PS will display the current axial image in the Image window if one already exists. To open a new axial image, control-click (or right mouse button click) the Axial button and select Load Axial... from the contextual menu. This will open the OSX file navigation window from which you can navigate to, select and open the axial file. You may optionally simply drag and drop the axial file into the Image window. Note: when opening a single image, the file's name is ignored.

SingleImageLoader

To simultaneously open up to 9 images using the PS6 naming conventions described above, option-click the Axial button or select Load All... from the contextual menu. PS will open a file navigation window and prompt you to open an image. Navigate to the MPR image's folder (e.g. a folder named for the patient) and open any image in the folder. PS will search that folder and open all images that adhere to the image file naming conventions. You may also simultaneously drag and drop multiple images into the Image window. If the drag and drop consists of more than one image file, PS will load the images according to the file naming conventions.

MultiImageLoader

CT and MR Image Calibration
  • To calibrate a CT (or MR) image you must first activate one of the MPR group images (axial, equator, sagittal, t-coronal or t-meridian) then enable and position the MPR ruler in the Image window.
  • Click the Ruler button in the MPR image controls group (its just above the button labeled Angle) to display Plaque Simulator's MPR calibration ruler.
  • Drag Plaque Simulator's MPR ruler over the calibration ruler of the image or any object in the image of known dimensions, typically about 40 or 50 mm.
  • Adjust the diameter of Plaque Simulator's MPR ruler by dragging the yellow control boxes until the magenta circle fits the known object. In the example on the right, the diameter of Plaque Simulator's MPR ruler represents 50 mm according to the green calibration rulers in the image.
  • With the MPR ruler still enabled, click the Calibrate button in the MPR Image controls group to open the calibration dialog sheet.
    CTGroupAxial
  • Enter the diameter in mm (e.g. 50 mm). Buttons for 30, 40 and 50 mm diameter presets are also provided as a convenience.
  • You can propogate this calibration to any or all other MPR images that you know will use the same calibration by individually enabling the various checkboxes or with the Select All button.
  • Click the OK button to exit the sheet.
CalibrateImageRuler
CalibrateImageDialog