Class: NodeLinearKetyEstimator

Node Icon

Fit a contrast agent concentration (CA) curve to the Kety Model (also known as the Tofts model). Both 2 and 3 parameter models can be used. In the three parameter model CA residing in the vascular compartment is included in the model. To select model, use ‘Normal’ or 'Extended' for the two and three parameter models, respectively.Three inputs can be used. An image with CA concentation (in milli molar) and an AIF is required. To speed up the calculations a mask can be used to reduce the region where the analysis is performed to a part of the image. A linear least squares method is used for the fitting.



Input contrast agent concentration map.

Type: Image4DFloat, Required, Single


Input arterial input function.

Type: CurveCollection, Required, Single


Input mask which defines the region where the Kety estimator will be applied.

Type: Image4DBool, Optional, Single



Ktrans map. A measure of capillary permeability in each voxel.

Type: Image4DFloat


Ve map. The fractional volume of the extravascular extracellular space.

Type: Image4DFloat


Vp map. The fractional plasma volume.

Type: Image4DFloat


Kety Model Selection

Use Normal for the two parameter model and Extended for the 3 parameter model.

Values: Normal, Extended

Set undefined values to Number

Undefined values (failed fits) are set to this value.


1. Murase K. Efficient method for calculating kinetic parameters using T1-weighted dynamic contrast-enhanced magnetic resonance imaging. Magn Reson Med 2004;51:858–862

See also