Dynamic Cerebral Contrast-enhanced Perfusion MRI - Biomedical Signal Analysis: Contemporary Methods and Applications - page 311

(a) (b)

(c) (d)

Figure 11.5
Quantitative analysis of clustering results with regard to side asymmetry of brain
perfusion in analogy to figure 11.4 for vector quantization by fuzzy clustering based
on deterministic annealing. For a better orientation, an anatomic EPI scan of the
analyzed slice is underlaid in (a) and (b). The X-axis represents the scan number
while the Y-axis is arbitrary for (c) and (d).

slice position, are presented in figure 11.10. Clusters #1, #3, #4, and
#15 represent larger vessels located primarily in the cerebral sulci,
while most of the other clusters seem to correspond to parenchymal
vascularization. The important difference from the results of the stroke
subject data in figures 11.1, 11.2, 11.3, and 11.5 is evident: the side-
asymmetry with regard to both the temporal pattern and the amplitude
of brain perfusion is here nonexistent. This fact becomes obvious since