AbstractID: 8435 Title: Problems with two automatic methods for SPECT-SPECT and SPECTMRI Volume Matching
We evaluated two different releases of commercial software for
SPECT-SPECT (using mutual information) and SPECT-MRI (using surface
matching) volume registration. We found the matching to be inadequate
for localizing on the SPECT scan spatial structural identified on the
MRI scan in 13 out of 23 SPECT-MRI cases, and in 4 out of 18
SPECT-SPECT cases. The failures of this software to successfully
produce a valid volume match are not the result of operator error, as
in some cases the analysis was performed as many as three separate
times by persons of various training levels (drawn from a pool
consisting of a nuclear medicine technologist, an experienced nuclear
medicine radiologist, and an experienced nuclear medicine
physicist). Additionally, the data input into the commercial tool was
in full cubic voxel format as required. Significant mis-registration
errors were identified when applying ROIs defined on the MRI scan to
the SPECT data. These errors were most readily apparent in the lower
brain areas (such as the medulla and cerebellar hemispheres) where
some structures are clearly outside the region of the SPECT brain data
after the automatic registration. This was confirmed both by numeric
evaluation of the SPECT voxel data and explicit visualization (using
both the commercially provided "cursor tool", and a fusion tool
locally developed for use with IBM’s Data Visualization Explorer
(DX)). Based on these findings, we recommend caution when applying
these automated methods of volume matching.