Despite the known validity of clinical diagnostic criteria, significant overlap of clinical symptoms between
Frontotemporal dementia (FTD) subtypes exists in several cases, resulting in great uncertainty of the diagnostic boundaries.
We evaluated the perfusion between FTD subtypes using brain perfusion 99mTc-HMPAO SPECT with Brodmann areas
(BA) mapping. NeuroGamTM software was applied on single photon emission computed tomographic (SPECT) studies
for the semi-quantitative evaluation of perfusion in BA and the comparison with the software’s normal database. We
studied 91 consecutive FTD patients: 21 with behavioural variants (bvFTD), 39 with language variants (lvFTD) [12 with
progressive non-fluent aphasia (PNFA), 27 with semantic dementia (SD)], and 31 patients with progressive supranuclear
palsy (PSP)/corticobasal degeneration (CBD). Stepwise logistic regression analyses showed that the BA 28L and 32R
could independently differentiate bvFTD from lvFTD, while the BA 8R and 25R could discriminate bvFTD from SD and
PNFA, respectively. Additionally, BA 7R and 32R were found to discriminate bvFTD from CBD/PSP. The only BA that
could differentiate SD from PNFA was 6L. BA 6R and 20L were found to independently differentiate CBD/PSP from
lvFTD. Moreover, BA 20L and 22R could discriminate CBD/PSP from PNFA, while BA 6R, 20L and 45R were found to
independently discriminate CBD/PSP from SD. Brain perfusion SPECT with BA mapping can be a useful additional tool
in differentiating FTD variants by improving the definition of brain areas that are specifically implicated, resulting in a
more accurate differential diagnosis in atypical or uncertain forms of FTD.