Biomedical Engineering Reference
In-Depth Information
Fig. 3.5
The cardiac planes (SA, HLA, VLA) and a representative coronal plane of the final image
are shown for the serial pipeline in (
a
) and for the simplified pipeline with MCIRs in (
b
). For the
coronal slices the
-map is overlaid with the respective PET data. Line profiles indicated in the SA
views are given in Fig.
3.6
μ
3.2.4
Results
The serial pipeline and the simplified pipeline with MCIRs are applied to the same
XCAT software phantom data that is used for the evaluation part of Sect.
2.3
.
The underlying data is described in more detail in Sect.
2.1.6
. To be precise, the
SSD V
AMPIRE
result in Fig.
2.7
represents exactly the result of the simplified
pipeline with MCIRs to be discussed in the following. We do not include the
simplified pipeline (
without
MCIRs) into this evaluation as the strategy is very
close to the strategy of the simplified pipeline
with
MCIRs and MCIRs are generally
advantageous over simple averaging [
4
,
110
].
The average values (over all 25 gates) of the validation criteria described in the
evaluation part of Sect.
2.3
are summarized in Table
3.1
for both pipelines. The
values for the average and maximum endpoint error are further plotted in Fig.
3.4
for each gate individually. For all gates the average endpoint errors are below the
voxel size. The final corrected images of the two approaches are shown in Fig.
3.5
.
The images are essentially very similar which is supported by the line profiles in
Fig.
3.6
. On the one hand, this shows that we do not lose any accuracy due to the
approximation of the decoupled respiratory and cardiac motion using the simplified
pipeline. On the other hand, we are now able to apply our motion correction strategy
to PET data with a fine dual gating. The improvement due to motion correction
becomes obvious by comparing the results in Fig.
3.5
with Fig.
2.10
b.
In conclusion, we have seen several methods for motion correction in gated
PET. We discussed a pure gating-based technique with optimal gating. We further
presented various methods combining gating with motion estimation and correction.
For the particular case of dual gated PET the presented simplified pipelines provide
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