Breast cancer and non-malignant breast data: Quantification by FPT - Signal Processing in MRS with Biomedical Applications - page 326

shape spectrum (left upper panel (i)), which shows only a single resonance at
3.22 ppm. This was phosphoethanolamine (k = 5) which was overestimated,
whereas phosphocholine (k = 4) was unresolved. At N P = 1500 in the left
middle panel (ii) of Fig. 10.5 the component shape spectrum is converged
with peaks k = 4 and 5 being resolved with correct heights, as was the case
all the other peaks. Phosphocholine is seen to lie completely underneath PE.
Stability of convergence is confirmed at N P = 2000 in the lower panels for
both the absorption component shape spectrum (iii) and the total shape spec
trum (vi). For longer partial signal lengths and for the full signal length, this
was also the case.
For the data corresponding to malignant breast tissue, the convergence of
metabolite concentrations is illustrated on Fig. 10.6 for N P = 1000, 1500 and
2000. Before convergence, at N P = 1000 neither the concentrations of peaks
k = 4 (PCho) nor k = 5 (PE) are correctly assessed in the reconstruction
(top panel (i)) and there is a slight discrepancy in the concentrations of peaks
k = 3 (Cho), k = 6 (GPC), k = 7 (β−Glc) and k = 8 (Tau). At N P = 1500
(middle panel (ii)) and N P = 2000 (bottom panel (iii)), all of the metabolite
concentrations are observed to be correct, both numerically and by the graphic
representations. The metabolite concentrations were verified as correct for
higher N P , as well as for the full signal length N.
10.4.4 Comparison of the Pade findings for normal breast,
fibroadenoma and breast cancer
We compare the converged absorption component shape spectra and total
shape spectra for normal breast, fibroadenoma and breast cancer. The con
verged Padereconstructed absorption component and total shape spectra
within the range of 3.2 ppm to 3.3 ppm are shown for the normal breast
data ( Fig. 10.7 , top panels (i) and (iv)), fibroadenoma (middle panels (ii) and
(v)) and malignant breast data (bottom panels (iii) and (vi)). The amplitudes
of all the metabolites within this frequency range are low for the normal data,
β−glucose at 3.25 ppm (k = 7) is predominant, myoinositol (k = 9) at 3.28
ppm is the next most prominent peak. The phosphocholine peak is minimal.
The amplitudes of all the peaks are larger within the range of 3.2 ppm and
3.3 ppm for the fibroadenoma, in comparison to the spectra for the normal
breast. Betaglucose at 3.25 ppm (k = 7) is also the largest peak in the
spectrum of the fibroadenoma within this frequency range. The difference
between the total and component absorption shape spectrum is wellseen for
the fibroadenoma, since the peak (k = 4+5) at 3.22 ppm is approximately the
same height as myoinositol (k = 9 at 3.28 ppm) for the total shape spectrum,
whereas myoinositol is obviously larger than the resolved peaks k = 4 (PCho)
and k = 5 (PE) 3.22 ppm in the converged component shape spectrum.
For the malignant breast data the spectra have a notably different pattern
within the range of 3.2 ppm and 3.3 ppm. The taurine peak (k = 8) at 3.27
ppm is the largest, with peak k = 7 (β−Glc) at 3.25 ppm among the smaller