Region of Interest
The English term region of interest, ROI abbreviated means translated " area of interest". It is generally used to select a range from a trace to statistically evaluate ( for example, maximum value, average value, width of a peak, area under the curve). As measured curves are often used count rates recorded time, spectrally or along a path.
It is used as a two - or three-dimensional region in the computer-based imaging, and the imaging process and is often encountered in nuclear medicine.
Choices for ROIs
ROIs can be operated manually, semi -automatically or fully automatically by evaluation software. We distinguish:
- Manual ROI: The user draws by hand - with keyboard, computer mouse, light pen or joystick - an area itself.
- Semi-automatic ROI: The evaluation supports the user when drawing the ROI. The user draws, for example, only one line, the evaluation closes automatically and thus defines the evaluation range. Or: The user defines gross fixed an area within which the evaluation identified a region that is defined by points having values above a user-specified threshold.
- Fully automatic ROIs: The evaluation determined without operator intervention criteria of demarcation.
Multidimensional ROIs
Mostly it is in the region of interest to an examined organ or a representative subsurface region. One can compare a ROI with a probe in the image area of any size and shape. The investigated within a ROI parameters can be, for example: count rate (number per unit time), SUV (English: Standardized Uptake Value) in positron emission tomography, during the counting rate over a time course in the scintigraphy of the kidney or Hounsfield value in computed tomography.
ROIs can be created not only in the two-dimensional visual field, but also in space, ie describe three-dimensional structures.
Source
- Udalrich Büll, Gustav hearing (ed.): Clinical Nuclear Medicine. 2nd edition. VCH Verlagsgesellschaft, 1990, ISBN 3-527-15427-2.
- Metabolism
- Nuclear Medicine