Multiplet resonances in MRS data from normal and cancerous prostate - Signal Processing in MRS with Biomedical Applications - page 350

two extremes of the total shape spectrum that approximately correct heights
and widths (lactate and alanine at 1.33 ppm and 1.49 ppm respectively and
myoinositol and lactate at≈4.07 ppm and 4.12 ppm, respectively) were seen.
The admixture of the absorption and dispersive mode is apparent in the region
between≈3.05 ppm and 3.3 ppm, reflected in the appearance of three peaks
that are broadened with lowered heights and upward distortion. In the bottom
panel of Fig. 11.2 , the converged total absorption shape spectrum is shown
at N P = 800, and this was without any dispersive modes whatsoever.
The converged absorption component shape spectrum (top panel (i)) and
total absorption shape spectrum (bottom panel (i)) at N P = 800 are com
pared from 2.40 ppm to 3.70 ppm for normal glandular prostate ( Fig. 11.3 ) .
Therein, phosphocholine at 3.23 ppm and glycerophosphocholine at 3.24 ppm
are fully resolved in the component shape spectrum, while only a single peak
appears on the total shape spectrum. From the total shape spectrum one can
merely guess that the peaks are triplets assigned to myoinositol with three
serrations centered respectively at≈3.55 ppm and 3.66 ppm. In the Pade
reconstructed component shape spectrum, it is clearly seen there are three
overlapping components at both of these chemical shift frequencies. Simi
larly, the two triply serrated peaks centered at≈3.43 ppm and 3.26 ppm
corresponding to taurine on the total shape spectrum, are shown in panel (i)
to be comprised of three components each. For the peaks centered at≈3.26
ppm, this would be practically impossible to ascertain from the total shape
spectrum, especially towards the righthand side which abuts against the GPC
and PCho peaks. It would be just guesswork to even suggest from the total
shape spectrum that the broad structure with a prominent peak centered at
about 3.1 ppm has two components that correspond to polyamine.

11.3.2 Normal stromal prostate tissue: MR spectral data

reconstructed by FPT
Table 11.5 shows the reconstructed data by the FPT (−) for normal stromal
prostate at partial signal lengths N P = 500 and N P = 600. At the shorter
signal length N P = 500 (upper panel (i)) for the normal stromal tissue the
pattern was quite similar to that described for the normal glandular prostate
data. Two resonances were missing: peak k = 11 phosphocholine at 3.230242
ppm and the component of the taurine triplet at 3.250298 ppm (k = 13).
At N P = 500 all reconstructed spectral parameters and concentrations were
fully exact for peak k = 1 (lactate) and peak k = 5 of the citrate doublet.
The spectral parameters and computed concentrations were nearly correct for
other resonances at the outermost regions of the spectrum (k = 2, 3, 5−7
and k = 25−27). For alanine (k = 2) other than the last two digits of the
|d − k

|all the spectral parameters and computed concentration were exact at
N P = 500. For the other components of the doublets of doublets of citrate and
for creatine (k = 7) the chemical shift, Im(ν − k ) and concentrations were exact
and the|d − k |were correct to 4 or 5 of the six decimal places at N P = 500. The