Diagnostic value of high signal abnormalities on T2 weighted MRI in the differentiation of Alzheimer's, frontotemporal and vascular dementias.
OBJECTIVE
The occurrence of high signal abnormalities on T2 weighted images is strongly age related. The diagnostic value of these changes in a younger population with dementia is not currently known. We studied the potential of high signal changes on magnetic resonance imaging (MRI) in differentiating Alzheimer's disease (AD), frontotemporal dementia (FTD) and vascular dementia (VaD) in younger patients.


METHODS
High signal abnormalities were rated, using a previously validated scale, from hard copies of T2 weighted axial images of 102 patients with AD (n=49), VaD (n=31), FTD (n=22) (mean ages 63-65 years).


RESULTS
High signal abnormalities were widespread across AD, VaD and FTD. Although they were most frequent and most severe in the VaD group only lacunes and grade III deep white matter hyperintensities (DWMH) were specific for these patients.


CONCLUSIONS
High signal changes on T2 weighted images on MRI are common across degenerative (AD and FTD) and vascular dementias. Although lacunes and grade III DWMH are specific for VaD, the low sensitivities (sensitivities: for lacunes, 0.32; for grade III DWMH, 0.16) limit their use as diagnostic markers for VaD. High signal changes on MRI should be interpreted with caution in dementias. Their presence, even in younger patients, should not deter one from diagnosing AD or FTD.
Varma
Anoop R
AR
Cerebral Function Unit, Neurology Department, Manchester Royal Infirmary, Central Manchester Healthcare Trust, Oxford Road, Manchester, UK. anoop.varma@btinternet.com
Laitt
R
R
Lloyd
J J
JJ
Carson
K J
KJ
Snowden
J S
JS
Neary
D
D
Jackson
A
A
D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis*; D001479:Basal Ganglia / Q000473:pathology; D015140:Dementia, Vascular / Q000175:diagnosis*; D005260:Female; D005625:Frontal Lobe / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D013702:Temporal Lobe / Q000473:pathology*