The role of brain perfusion SPECT in the diagnosis of frontotemporal dementia: A systematic review.

BACKGROUND AND PURPOSE: Frontotemporal dementia (FTD) is the second most common cause of presenile dementia. The clinical distinction between FTD, Alzheimer's disease (AD), and other dementias is a clinical challenge. Brain perfusion SPECT may contribute to the diagnosis of FTD, but its value is unclear. METHODS: We performed a systematic review to investigate the diagnostic accuracy of the brain SPECT in (1) distinguishing FTD from AD and other dementias and (2) differentiating FTD variants. RESULTS: Overall, 391 studies were retrieved on the initial search and 35 studies composed the final selection, comprising a total number of 3142 participants of which 1029 had FTD. The sensitivity and the specificity for the differential diagnosis of FTD versus AD ranged from 56% to 88% and from 51% to 93%, respectively. SPECT is not superior to the clinical method of diagnosis, but the combination of SPECT with clinical data seems to improve the diagnostic accuracy. CONCLUSION: Brain perfusion SPECT has a limited value in the diagnostic framework of FTD. SPECT can be performed when FDG-PET is not available. SPECT is recommended only for selected cases when the diagnosis is challenging using conventional methods.

Behavioral variant of frontotemporal dementia or frontal variant of Alzheimer's disease? A case study.

Alzheimer's disease (AD) has heterogeneous clinical presentations. Amnestic progressive disorder leading to dementia is the most typical, but non-amnestic presentations are also recognized. Here we report a case of frontal variant of AD. A right-handed woman, aged 68 years, was referred for progressive behavioral disorders and personality changes. She had a corroborated history of dietary changes, hyperorality, impulsivity, affective indifference and apathy, with functional impairment. Cognitive assessment yielded severe executive deficits. Positron emission tomography with fluorodeoxyglucose showed marked hypometabolism in frontotemporal regions, with relative preservation of parietal regions. CSF AD biomarkers showed low Aß42, high Tau and high P-Tau. The patient fulfilled criteria for probable behavioral variant frontotemporal dementia. However, considering the AD pathophysiological signature on CSF biomarkers, a diagnosis of frontal variant of AD was established. In the perspective of disease-modifying therapies, it is important to identify atypical Alzheimer presentations, as these patients may be candidates for specific treatments.

A doença de Alzheimer (DA) tem apresentações clínicas heterogêneas. Amnésia progressiva associada a demência é a forma mais comum, mas apresentações não-amnésticas são também reconhecidas. Relatamos um caso de variante frontal da DA. Um mulher destra, de 68 anos, consultou-se devido a transtornos comportamentais progressivos, com alterações de personalidade. Modificações de padrão alimentar, hiperoralidade, impulsividade, indiferença afetiva e apatia, com declínio funcional, foram corroboradas pela família. A avaliação cognitiva evidenciou grave disfunção executiva. A tomografia de emissão de pósitrons com flúordeoxiglicose revelou proeminente hipometabolismo em regiões frontotemporais, com relativa preservação de regiões parietais. A análise de biomarcadores de DA no líquido cefalorraquidiano mostrou redução de níveis de Aß42, com aumento de níveis de Tau e P-Tau. A paciente preencheu critérios diagnósticos para demência frontotemporal (variante comportamental) provável. Contudo, considerando o perfil de biomarcadores em favor de fisiopatologia da DA, o diagnóstico de variante frontal de DA foi estabelecido. Na perspectiva de tratamentos modificadores da doença, é crucial identificar apresentações atípicas da DA, visto que esses pacientes podem ser candidatos a terapias específicas.