Voxel-based quantitative analysis of brain images from ¹⁸F-FDG PET with a block-matching algorithm for spatial normalization.
OBJECTIVE
Statistical Parametric Mapping (SPM) is widely used for the quantitative analysis of brain images from ¹⁸F fluorodeoxyglucose positron emission tomography (FDG PET). SPM requires an initial step of spatial normalization to align all images to a standard anatomic model (the template), but this may lead to image distortion and artifacts, especially in cases of marked brain abnormalities. This study aimed at assessing a block-matching (BM) normalization algorithm, where most transformations are not directly computed on the overall brain volume but through small blocks, a principle that is likely to minimize artifacts.


METHODS
Large and/or small hypometabolic areas were artificially simulated in initially normal FDG PET images to compare the results provided by statistical tests computed after either SPM or BM normalization.


RESULTS
Results were enhanced by BM, compared with SPM, with regard to (i) errors in the estimation of large defects volumes (about 2-fold lower) because of a lower image distortion, and (ii) rates of false-positive foci when numerous or extended abnormalities were simulated. These observations were strengthened by analyses of FDG PET examinations from epileptic patients.


CONCLUSIONS
Results obtained with the BM normalization of brain FDG PET appear more precise and robust than with SPM normalization, especially in cases of numerous or extended abnormalities.
CRAN, CNRS UMR 7039, Nancy, France.
Christophe
C
Person
Valérie
V
Louis-Dorr
Sylvain
S
Poussier
Olivier
O
Commowick
Grégoire
G
Malandain
Louis
L
Maillard
Didier
D
Wolf
Nicolas
N
Gillet
Véronique
V
Roch
Gilles
G
Karcher
Pierre-Yves
PY
Marie
D000328:Adult; D000465:Algorithms; D000704:Analysis of Variance; D001921:Brain / Q000000981:diagnostic imaging*; D001931:Brain Mapping / Q000379:methods*; D003627:Data Interpretation, Statistical; D004833:Epilepsy, Temporal Lobe / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012016:Reference Values; D018709:Statistics, Nonparametric; D020521:Stroke / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18