Density Value

Synapse uses the information embedded in an image to convert the pixel data into quantifiable values. Examples of these conversions include the display of Hounsfield Units (HU) on CT images or optical density (OD) on computed radiography (CR) images. Image type determines the value units.

Note:
  • The density units for mean, standard deviation, maximum value, and minimum values vary depending on the modality. For example, CT uses HU, and PT uses Standard Uptake Values (SUV). SUV correction methods are dependent on the DICOM data available in the series. To change the SUV correction method, see Configuring Annotations Settings.
  • For Fujifilm for-processing images, the density, mean, standard deviation, maximum value, and minimum values are calculated after applying an image processing preset.

Synapse hides the SD, M, Min, Max, and density values for images for the following reasons:

  • If an image displays in color (not monochromatic).
  • In most cases, if an image does not contain both tags rescale slope and rescale intercept, except for MR images. MR does not require the rescale slope and rescale intercept tags to display density values.

Additional Considerations

For Fujifilm CR/DX images with Image Processing Presets, density value measurements are performed on images after Fujifilm image processing is applied. When a preset includes image processing, the density value measurement will include changes.

Related Topics

Annotations and Measurements Overview