Utility of Amyloid and FDG-PET in Clinical Practice: Differences Between Secondary and Tertiary Care Memory Units

Article type: Research Article

Authors: Lage, Carmen^a | Suarez, Andrea Gonzalez^a | Pozueta, Ana^a | Riancho, Javier^a | Kazimierczak, Martha^a | Bravo, Maria^a | Jimenez Bonilla, Julio^b | de Arcocha Torres, Marıa^b | Quirce, Remedios^b | Banzo, Ignacio^b | Vazquez-Higuera, Jose Luis^a | Rabinovici, Gil D.^c | Rodriguez-Rodriguez, Eloy^a | Sánchez-Juan, Pascual^{a; *}

Affiliations: [a] Neurology Service and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), ‘Marqués de Valdecilla’ University Hospital, University of Cantabria, Institute for Research ‘Marqués de Valdecilla’ (IDIVAL), Santander, Spain | [b] Department of Nuclear Medicine, University Hospital Marqués de Valdecilla, University of Cantabria, Molecular Imaging Group - IDIVAL, Santander, Spain | [c] Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, USA; Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Lab, Berkeley, CA, USA; Memory and Aging Center, University of California San Francisco, San Francisco, CA, USA

Correspondence: [*] Correspondence to: Pascual Sánchez-Juan, MD, ‘Marqués de Valdecilla’ University Hospital, Planta Baja Valdecilla Sur, Avda Marqués de Valdecilla s/n, 39011 Santander (Cantabria), Spain. Tel.: +34 942202520 /Ext. 73560); E-mail: psanchez@humv.es.

Abstract: The clinical utility of amyloid positron emission tomography (PET) has not been fully established. Our aim was to evaluate the effect of amyloid imaging on clinical decision making in a secondary care unit and compare our results with a previous study in a tertiary center following the same methods. We reviewed retrospectively 151 cognitively impaired patients who underwent amyloid (Pittsburgh compound B [PiB]) PET and were evaluated clinically before and after the scan in a secondary care unit. One hundred and fifty concurrently underwent fluorodeoxyglucose (FDG)-PET. We assessed changes between the pre- and post-PET clinical diagnosis and Alzheimer’s disease treatment plan. The association between PiB/FDG results and changes in management was evaluated using χ2 and multivariate logistic regression. Concordance between classification based on scan readings and baseline diagnosis was 66% for PiB and 47% for FDG. The primary diagnosis changed after PET in 17.2% of cases. When examined independently, discordant PiB and discordant FDG were both associated with diagnostic change (p < 0.0001). However, when examined together in a multivariate logistic regression, only discordant PiB remained significant (p = 0.0002). Changes in treatment were associated with concordant PiB (p = 0.009) while FDG had no effect on treatment decisions. Based on our regression model, patients with diagnostic dilemmas, a suspected non-amyloid syndrome, and Clinical Dementia Rating <1 were more likely to benefit from amyloid PET due to a higher likelihood of diagnostic change. We found that changes in diagnosis after PET in our secondary center almost doubled those of our previous analysis of a tertiary unit (9% versus 17.2%). Our results offer some clues about the rational use of amyloid PET in a secondary care memory unit stressing its utility in mild cognitive impairment patients.

Keywords: Alzheimer’s disease, amyloid, dementia, FDG, PET, PiB

DOI: 10.3233/JAD-170985

Journal: Journal of Alzheimer's Disease, vol. 63, no. 3, pp. 1025-1033, 2018