Brix

Class: NodeBrix

Node Icon

Calculates pharmacokinetic maps using a modified Brix model with the assumption that signal enhancement is linearly dependent on contrast agent (CA) concentration. The model is given by:

\(\displaystyle \frac{S(t)}{S(0)} = 1+A \frac{kep}{kel-kep} \Big(\exp(-kep\cdot t)-\exp(-kel\cdot t)\Big)\)

in which \(S(t)\) is the dynamic signal and \(S(0)\) is the baseline signal.

Two imputs are required: A baseline signal and a dynamic signal.These must correspond to data acquisition sequences with identical settings(except number of frames). An optional mask can also be provided to limit the calculations to a region.

Produces a pharmacokinetic maps A [arb. unit], kel [min \(^{-1}\)] and kep [min \(^{-1}\)].

Inputs

Signal

The dynamic image.

Type: Image4DFloat, Required, Single

Baseline

The baseline image.

Type: Image4DFloat, Required, Single

Mask

Input mask which defines the region where the calculations will be performed.

Type: Image4DBool, Optional, Single

Outputs

A

Amplitude parameter map.

Type: Image4DFloat

Kel

The elimination constant parameter map.

Type: Image4DFloat

Kep

The exchange rate constant from the EES to plasma.

Type: Image4DFloat

Residual Norm

The residual norm.

Type: Image4DFloat

Settings

Guess A per voxel Boolean

Allow A to be a fitting parameter per voxel (TRUE) or assume a sptially constant A (FALSE).

A Number

Amplitude parameter.

Kel (min¯¹) Number

Contrast elimination rate.

Kep (min¯¹) Number

Contrast extraction rate.

References

H.T. Ma, J. F. Griffith, D. K. Yeung, and P. C. Leung, “Modified brix model analysis of bone perfusion in subjects of varying bone mineral density,” J. Magn. Reson. Imaging, vol. 31, no. 5, pp. 1169–1175, May 2010

Keywords: Brix, dynamic, contrast, dce, kep, kel