Density Value

Introduction

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

Depending on the modality, a Modality Lookup Table (LUT) might be applied to the pixel value. In this case, the larger value can correspond to either the darker area of the image or the brighter area of the image.

Note:

The density units for mean, standard deviation, maximum value, and minimum values vary depending on the modality. For example, CT uses Hounsfield Unit, 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 CT images that are "non-Fuji" modalities with image processing presets, the density value measurements are NOT affected. The density value is always calculated using the pixel data, not the preset 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

Configuring Annotations Settings