PURPOSE: The clinical potential of striatal imaging with dopamine transporter (DAT) SPECT tracers is hampered by the limited capability to recover activity concentration ratios due to partial volume effects (PVE). We evaluated the accuracy of a least squares method that allows retrieval of activity in regions of interest directly from projections (LS-ROI). METHODS: An Alderson striatal phantom was filled with striatal to background ratios of 6:1, 9:1 and 28:1; the striatal and background ROIs were drawn on a coregistered X-ray CT of the phantom. The activity ratios of these ROIs were derived both with the LS-ROI method and with conventional SPECT EM reconstruction (EM-SPECT). Moreover, the two methods were compared in seven patients with motor symptoms who were examined with N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) (FP-CIT) SPECT, calculating the binding potential (BP). RESULTS: In the phantom study, the activity ratios obtained with EM-SPECT were 3.5, 5.3 and 17.0, respectively, whereas the LS-ROI method resulted in ratios of 6.2, 9.0 and 27.3, respectively. With the LS-ROI method, the BP in the seven patients was approximately 60% higher than with EM-SPECT; a linear correlation between the LS-ROI and the EM estimates was found (r=0.98, p=0.03). CONCLUSION: The LS-ROI PVE correction capability is mainly due to the fact that the ill-conditioning of the LS-ROI approach is lower than that of the EM-SPECT one. The LS-ROI seems to be feasible and accurate in the examination of the dopaminergic system. This approach can be fruitful in monitoring of disease progression and in clinical trials of dopaminergic drugs.
PURPOSE: The clinical potential of striatal imaging with dopamine transporter (DAT) SPECT tracers is hampered by the limited capability to recover activity concentration ratios due to partial volume effects (PVE). We evaluated the accuracy of a least squares method that allows retrieval of activity in regions of interest directly from projections (LS-ROI). METHODS: An Alderson striatal phantom was filled with striatal to background ratios of 6:1, 9:1 and 28:1; the striatal and background ROIs were drawn on a coregistered X-ray CT of the phantom. The activity ratios of these ROIs were derived both with the LS-ROI method and with conventional SPECT EM reconstruction (EM-SPECT). Moreover, the two methods were compared in seven patients with motor symptoms who were examined with N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) (FP-CIT) SPECT, calculating the binding potential (BP). RESULTS: In the phantom study, the activity ratios obtained with EM-SPECT were 3.5, 5.3 and 17.0, respectively, whereas the LS-ROI method resulted in ratios of 6.2, 9.0 and 27.3, respectively. With the LS-ROI method, the BP in the seven patients was approximately 60% higher than with EM-SPECT; a linear correlation between the LS-ROI and the EM estimates was found (r=0.98, p=0.03). CONCLUSION: The LS-ROI PVE correction capability is mainly due to the fact that the ill-conditioning of the LS-ROI approach is lower than that of the EM-SPECT one. The LS-ROI seems to be feasible and accurate in the examination of the dopaminergic system. This approach can be fruitful in monitoring of disease progression and in clinical trials of dopaminergic drugs.
Authors: Albert Cot; Carles Falcón; Cristina Crespo; Josep Sempau; Deborah Pareto; Santiago Bullich; Francisco Lomeña; Francisco Calviño; Javier Pavía; Domènec Ros Journal: J Nucl Med Date: 2005-09 Impact factor: 10.057
Authors: T Chaly; V Dhawan; K Kazumata; A Antonini; C Margouleff; J R Dahl; A Belakhlef; D Margouleff; A Yee; S Wang; G Tamagnan; J L Neumeyer; D Eidelberg Journal: Nucl Med Biol Date: 1996-11 Impact factor: 2.408
Authors: R B Innis; J P Seibyl; B E Scanley; M Laruelle; A Abi-Dargham; E Wallace; R M Baldwin; Y Zea-Ponce; S Zoghbi; S Wang Journal: Proc Natl Acad Sci U S A Date: 1993-12-15 Impact factor: 11.205
Authors: Stephen C Moore; Sudeepti Southekal; Mi-Ae Park; Sarah J McQuaid; Marie Foley Kijewski; Stefan P Müller Journal: IEEE Trans Med Imaging Date: 2011-09-29 Impact factor: 10.048
Authors: Valentina Berti; Cristina Polito; Silvia Ramat; Eleonora Vanzi; Maria Teresa De Cristofaro; Giannantonio Pellicanò; Francesco Mungai; Paolo Marini; Andreas Robert Formiconi; Sandro Sorbi; Alberto Pupi Journal: Eur J Nucl Med Mol Imaging Date: 2009-09-02 Impact factor: 9.236