The influence of temporal resolution and phase-encoding order on shape-based classification of dynamic contrast enhanced (DCE) MRI uptake curves in the breast

In DCE-MRI of the breast a T1-weighted dynamic imaging series is recorded during the uptake of a contrast agent (CA), usually Gd-DTPA. In clinical practice, temporal resolution is relatively low compared to the time-scale of the uptake process. This means that the signal intensity of voxels can change significantly during the acquisition of each dynamic. Depending on the applied protocol, each point of an uptake curve can represent, for instance, a certain time-point within the image-acquisition interval (as in linear or centric phase-encoding) or the whole image-acquisition interval (as in radial phase-encoding used in THRIVE). Thus, it is not necessarily a representation of the signal at the time-point that is assigned to the image (usually end of acquisition). This is due to the fact that the center of k-space, and therefore the timing of the acquisition of the central k-lines, is dominant in determining the overall signal intensity and contrast. Once we can use a higher temporal resolution, this undesired influence will diminish so that the obtained curve will more closely resemble the true uptake curve. However, this also means that the conventional curve classification schemes, such as Kuhl’s shape model [1] or the Three-Time-Point scheme (3TP) [2], will no longer be appropriate, since they have been developed and statistically validated for classification of low-temporal resolution curves. It appears that, until now, the variations caused by phase-encoding order and/or temporal resolution have been neglected. In this paper, we investigate the effects of these variations on shape-based curve classification.

@InProceedings { HTBVGH07,
  author       = "Heisen, M. and Twellmann, T. and Buurman, J. and Vilanova, Anna and Gerritsen, F.A. and Haar Romeny, B.M. ter",
  title        = "The influence of temporal resolution and phase-encoding order on shape-based classification of dynamic
                  contrast enhanced (DCE) MRI uptake curves in the breast",
  booktitle    = "Proceedings of the International Society of Magnetic Resonance in Medicine joint annual meeting (ISMRM 2007)
                  19-25 may 2007, Berlin, Germany",
  pages        = "1/1--1",
  year         = "2007",
  address      = "New York, New York, USA",
  note         = "ISMRM 2007, Berlin, Germany",
  url          = "http://graphics.tudelft.nl/Publications-new/2007/HTBVGH07"
}