Pathologically, it includes a heterogeneous group of sporadic and familial neuropsychiatric disorders. Pick disease is one of the neuropathological entities of FTD. Unlike AD, which increases in frequency with age, FTD is rare after the age of 75. Although the diagnosis of FTD is primarily clinical, neuroimaging serves several purposes: exclusion of other structural brain abnormalities that could clinically mimic FTD, differentiation of FTD from other neurodegenerative disorders (most commonly AD), and classification of the known subtypes of FTD [43]. Multimodal imaging is a promising approach in neuroimaging of FTD. Integrated PET/MRI systems allow a combination of structural and functional imaging in one examination that can increase sensitivity and specificity of these modalities in a smaller cohort of patients and thus may represent a method of choice in FTD [44]. CT Head Noncontrast CT head is used to exclude other lesions that may clinically mimic the disease. CT head with intravenous (IV) contrast or dual-phase imaging is not needed for initial evaluation. Dementia Amyloid PET/CT Brain Use of amyloid PET in FTD is limited to the exclusion of underlying amyloid brain pathology that can be seen in cases of AD with atypical presentation. PET tracers specific for tau protein deposits in the brain are currently being investigated, but no systematic studies on their application in FTD have been published [44]. FDG-PET/CT Brain FDG-PET is an established tool for differentiating FTD and AD and classifying different FTD subtypes. FDG-PET has a sensitivity of 60% and a positive predictive value of 78.5% for differentiating the subtypes of FTD [44]. The CMS coverage decision for payment for FDG-PET brain, in 2004, was based on FDG brain PET being a very valuable diagnostic study to differentiate AD and FTD in patients with documented cognitive decline of at least 6 months and a recently established diagnosis of dementia [45].
Dementia. Pathologically, it includes a heterogeneous group of sporadic and familial neuropsychiatric disorders. Pick disease is one of the neuropathological entities of FTD. Unlike AD, which increases in frequency with age, FTD is rare after the age of 75. Although the diagnosis of FTD is primarily clinical, neuroimaging serves several purposes: exclusion of other structural brain abnormalities that could clinically mimic FTD, differentiation of FTD from other neurodegenerative disorders (most commonly AD), and classification of the known subtypes of FTD [43]. Multimodal imaging is a promising approach in neuroimaging of FTD. Integrated PET/MRI systems allow a combination of structural and functional imaging in one examination that can increase sensitivity and specificity of these modalities in a smaller cohort of patients and thus may represent a method of choice in FTD [44]. CT Head Noncontrast CT head is used to exclude other lesions that may clinically mimic the disease. CT head with intravenous (IV) contrast or dual-phase imaging is not needed for initial evaluation. Dementia Amyloid PET/CT Brain Use of amyloid PET in FTD is limited to the exclusion of underlying amyloid brain pathology that can be seen in cases of AD with atypical presentation. PET tracers specific for tau protein deposits in the brain are currently being investigated, but no systematic studies on their application in FTD have been published [44]. FDG-PET/CT Brain FDG-PET is an established tool for differentiating FTD and AD and classifying different FTD subtypes. FDG-PET has a sensitivity of 60% and a positive predictive value of 78.5% for differentiating the subtypes of FTD [44]. The CMS coverage decision for payment for FDG-PET brain, in 2004, was based on FDG brain PET being a very valuable diagnostic study to differentiate AD and FTD in patients with documented cognitive decline of at least 6 months and a recently established diagnosis of dementia [45].