Localization of temporal epilepsy foci by subtraction ictal perfusion single photon emission computed tomography is enhanced when using 3D-OSEM iterative reconstruction.
Fiche publication
Date publication
novembre 2009
Auteurs
Membres identifiés du Cancéropôle Est :
Pr KARCHER Gilles
Tous les auteurs :
Ben Mahmoud S, Maillard L, Poussier S, Koessler L, El Khawaja MS, Laurens MH, Vespignani H, Karcher G, Marie PY
Lien Pubmed
Résumé
OBJECTIVES: Subtraction ictal single photon emission computed tomography (SPECT) images, provided by filtered back-projection (FBP), may exhibit a confusing high level of noise. This study was aimed at assessing an optimized three-dimensional ordered subset expectation maximization (3D-OSEM) iterative reconstruction in this setting. METHODS: On phantom images, parameters of 3D-OSEM reconstruction were selected as those providing the higher signal/noise ratio but a high enough spatial resolution, equivalent to that of conventional FBP reconstruction (full width at half-maximum = 11 mm). Thereafter, subtraction ictal ethylene cysteine dimer-SPECT coregistered to MRI and reconstructed with either FBP or 3D-OSEM were compared in 21 patients with well-characterized temporal epilepsy foci (subsequent successful surgical treatment). RESULTS: On subtraction images, the use of the selected 3D-OSEM reconstruction (five iterations, 16 subsets and a 9 mm Gauss filter) instead of FBP was associated with: (i) marked reductions in background activity (0.05 +/- 0.09 vs. 0.25 +/- 0.18 cps, P < 0.001) and in the size of temporal foci (10 +/- 7 vs. 14 +/- 11 cm, P = 0.01) and (ii) a trend toward higher accuracy in identifying the involved temporal lobes (86 vs. 76%). CONCLUSION: Localization of temporal epilepsy foci by subtraction ictal SPECT is likely to be enhanced by using 3D-OSEM rather than FBP reconstruction because of marked reductions in background activity and in the size of detected foci.
Référence
Nucl Med Commun. 2009 Nov;30(11):846-53.