Clinical Impact of a Second FDG-PET in Atypical/Unclear Dementia Syndromes.
Diagnosis of atypical/unclear dementia is often difficult and this delays treatment initiation. Several authors have shown that beyond standard dementia workup, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) reduces the number of unclear diagnoses, leads to earlier treatment, and has a beneficial impact on families. However, it is not uncommon that the FDG-PET findings are equivocal in this setting. For those cases, a repeat FDG-PET may clarify the diagnosis and prevent treatment delay. We retrospectively assessed the clinical impact of a repeat FDG-PET in 59 patients with atypical/unclear dementia syndromes and inconclusive initial FDG-PET. Changes in primary diagnosis, diagnostic confidence, and management following the second FDG-PET were examined. Conducting a second FDG-PET reduced the number of unclear diagnoses from 80% to 34% , led to diagnostic change in 24% of cases, and treatment modification in 22% of patients. Overall, the clinical impact was higher when initial diagnostic confidence was low and the second FDG-PET repeated ≥12 months after the first one. In tertiary care memory clinic settings, when diagnostic incertitude persists despite extensive evaluation and an equivocal FDG-PET, repeating the FDG-PET 12 months later can greatly clarify the diagnosis and improve management.
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.
David
D
Bergeron
Département d'imagerie médicale, CHU de Québec, PQ, Canada.
Jean-Mathieu
JM
Beauregard
Service de médecine nucléaire, Institut de Cardiologie et de Pneumologie de Québec (IUCPQ), PQ, Canada.
Jean
J
Guimond
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.
Marie-Pierre
MP
Fortin
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.
Michèle
M
Houde
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.
Stéphane
S
Poulin
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.|Département des Sciences Neurologiques, Université Laval, PQ, Canada.
Louis
L
Verret
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.|Département des Sciences Neurologiques, Université Laval, PQ, Canada.
Rémi W
RW
Bouchard
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, PQ, Canada.|Département des Sciences Neurologiques, Université Laval, PQ, Canada.
Robert
R
Laforce
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D003704:Dementia / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Atypical dementia; FDG-PET; brain imaging; differential diagnosis