Multiplet resonances in MRS data from normal and cancerous prostate - Signal Processing in MRS with Biomedical Applications - page 362

were resolved and with heights that were nearly correct at N P = 54.
The citrate peaks near 2.5 ppm and 2.75 ppm are single and narrower at
N P = 54, than on the converged total shape spectrum. The creatine peak
centered at around 3.05 ppm is widened and has a lower amplitude compared
to the peak corresponding to creatine on the converged total shape spectrum.
There is a single peak centered at 3.25 ppm at N P = 54 instead of the
two very narrow peaks and a triply serrated structure to the left. The peaks
at 3.35 ppm corresponding to scylloinositol and the triply serrated structure
corresponding to taurine centered at 3.43 ppm are not seen on the total shape
spectrum at N P = 54.
The two structures centered near 3.56 ppm and at 3.64 ppm correspond
ing to myoinositol are single peaks, although they should by triply serrated.
The converged total absorption shape spectrum at N P = 800 for the Pade
reconstructed data for malignant prostate is seen on the lower panel of Fig.
11.8 .
Figure 11.9 shows the converged absorption component shape spectrum
(top panel (i)) and total absorption shape spectrum (lower panel (ii)) for the
Padereconstructed data for malignant prostate. The spectrum is displayed
within the region between 2.40 ppm and 3.70 ppm at N P = 800. Comparing
the two panels, it can be seen that the triply and doubly serrated peaks on the
total shape spectrum merely suggest the number of components, such that it
is only from the converged component spectrum that the actual number of
underlying resonances is revealed.
As was true for normal stromal prostate, the polyamine peaks are small
in the case of prostate cancer. It would be much more di cult than for
the glandular prostate case to ascertain from the total shape spectrum that
there are precisely two PA components. On the total shape spectrum, the
citrate doublets centered near 2.53 ppm and 2.73 ppm appear as broad peaks
and there is only a hint of the doublet structures shown on the component
spectrum. While phosphocholine at 3.23 ppm and glycerophosphocholine at
3.24 ppm are completely resolved in the component shape spectrum, that is
not the case on the total shape spectrum.
11.3.4 Comparison of MRS retrievals from prostate tissue:
Normal glandular, normal stromal and cancerous
Figure 11.10 presents the converged Padereconstructed absorption compo
nent shape spectra, for the normal glandular prostate (top panel (i)), normal
stromal prostate (middle panel (ii)) and malignant prostate data (bottom
panel (iii)). The converged total shape spectra for these three cases are shown
in Fig. 11.11 .
For the normal glandular prostate, the most prominent spectral structures
besides the lactate resonance at 1.33 ppm, are the doublets of citrate doublets
at 2.5 ppm and 2.75 ppm, creatine peak at 3.04 ppm and tall, narrow choline
peak at 3.21 ppm.