Clinical Utility of Amyloid PET Imaging in the Differential Diagnosis of Atypical Dementias and Its Impact on Caregivers.
Recent studies have supported a role for amyloid positron emission tomography (PET) imaging in distinguishing Alzheimer's disease (AD) pathology from other pathological protein accumulations leading to dementia. We investigated the clinical utility of amyloid PET in the differential diagnosis of atypical dementia cases and its impact on caregivers. Using the amyloid tracer 18F-NAV4694, we prospectively scanned 28 patients (mean age 59.3 y, s.d. 5.8; mean MMSE 21.4, s.d. 6.0) with an atypical dementia syndrome. Following a comprehensive diagnostic workup (i.e., history taking, neurological examination, blood tests, neuropsychological evaluation, MRI, and FDG-PET), no certain diagnosis could be arrived at. Amyloid PET was then conducted and classified as positive or negative. Attending physicians were asked to evaluate whether this result led to a change in diagnosis or altered management. They also reported their degree of confidence in the diagnosis. Caregivers were met after disclosure of amyloid PET results and completed a questionnaire/interview to assess the impact of the scan. Our cohort was evenly divided between positive (14/28) and negative (14/28) 18F-NAV4694 cases. Amyloid PET resulted in a diagnostic change in 9/28 cases (32.1%: 17.8% changed from AD to non-AD, 14.3% from non-AD to AD). There was a 44% increase in diagnostic confidence. Altered management occurred in 71.4% (20/28) of cases. Knowledge of amyloid status improved caregivers' outcomes in all domains (anxiety, depression, disease perception, future anticipation, and quality of life). This study suggests a useful additive role for amyloid PET in atypical cases with an unclear diagnosis beyond the extensive workup of a tertiary memory clinic. Amyloid PET increased diagnostic confidence and led to clinically significant alterations in management. The information gained from that test was well received by caregivers and encouraged spending quality time with their loved ones.
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.
Mohamed Reda
MR
Bensaïdane
Département d'imagerie médicale, CHU de Québec, QC, Canada.
Jean-Mathieu
JM
Beauregard
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.
Stéphane
S
Poulin
Département d'imagerie médicale, CHU de Québec, QC, Canada.
François-Alexandre
FA
Buteau
Département d'imagerie médicale, CHU de Québec, QC, Canada.
Jean
J
Guimond
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.
David
D
Bergeron
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.|Département des Sciences Neurologiques, Université Laval, QC, Canada.
Louis
L
Verret
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.
Marie-Pierre
MP
Fortin
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.
Michèle
M
Houde
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.|Département des Sciences Neurologiques, Université Laval, QC, Canada.
Rémi W
RW
Bouchard
McGill University, QC, Canada.
Jean-Paul
JP
Soucy
Clinique Interdisciplinaire de Mémoire (CIME), CHU de Québec, QC, Canada.|Département des Sciences Neurologiques, Université Laval, QC, Canada.
Robert
R
Laforce
D000368:Aged; D000682:Amyloid / Q000378:metabolism*; D017028:Caregivers / Q000523:psychology; D003704:Dementia / Q000175:diagnosis / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography / Q000379:methods*; D011788:Quality of Life / Q000523:psychology; D011795:Surveys and Questionnaires
D000682:Amyloid
Alzheimer variants; Alzheimer’s disease; amyloid PET imaging; atypical dementia; caregivers; clinical utility; differential diagnosis; frontotemporal lobar degeneration; impact; primary progressive aphasia