Caudate atrophy on MRI is a characteristic feature of FTLD-FUS.
OBJECTIVE
Frontotemporal lobar degeneration (FTLD) can be subdivided into those in which the abnormal protein is tau (FTLD-TAU), the TAR DNA binding protein 43 (FTLD-TDP) and the fused in sarcoma protein (FTLD-FUS). We have observed severe caudate atrophy at autopsy in FTLD-FUS, and hence, we aimed to determine whether caudate atrophy on MRI is a feature that can distinguish FTLD-FUS from FTLD-TDP and FTLD-TAU.


METHODS
From a cohort of 207 cases of FTLD, we identified all cases of FTLD-FUS that had a volumetric antemortem head MRI (n = 3). Caudate and frontal lobe volumes were measured in all three cases using atlas-based parcellation and SPM5 and were compared to 10 randomly selected cases of FTLD-TDP and 10 randomly selected cases of FTLD-TAU. Total grey matter volumes were also calculated for all cases.


RESULTS
The FTLD-FUS cases had significantly smaller caudate volumes (P = 0.02) yet similar frontal lobe grey matter volumes (P = 0.12) compared to FTLD-TDP and FTLD-TAU. Caudate volumes when corrected for total grey matter volume (P = 0.01) or frontal lobe grey matter volume (P = 0.01) were significantly smaller in FTLD-FUS than in FTLD-TDP and FTLD-TAU and showed no overlap with the other two groups.


CONCLUSIONS
Caudate atrophy on MRI appears to be significantly greater in FTLD-FUS compared with FTLD-TDP and FTLD-TAU, suggesting that severe caudate atrophy may be a useful clinical feature to predict FTLD-FUS pathology.
Department of Neurology (Behavioral Neurology), Mayo Clinic, Rochester, MN 55905, USA. josephs.keith@mayo.edu
K A
KA
Josephs
J L
JL
Whitwell
J E
JE
Parisi
R C
RC
Petersen
B F
BF
Boeve
C R
CR
Jack
D W
DW
Dickson
D000368:Aged; D001284:Atrophy; D015415:Biomarkers / Q000378:metabolism; D001931:Brain Mapping / Q000379:methods; D002421:Caudate Nucleus / Q000378:metabolism / Q000473:pathology*; D015331:Cohort Studies; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003937:Diagnosis, Differential; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology*; D057180:Frontotemporal Dementia / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D034702:RNA-Binding Protein FUS / Q000378:metabolism*; D012720:Severity of Illness Index; D016875:tau Proteins / Q000378:metabolism
D015415:Biomarkers; D004268:DNA-Binding Proteins; D034702:RNA-Binding Protein FUS; D016875:tau Proteins