CSF and MRI markers independently contribute to the diagnosis of Alzheimer's disease.

Background: Decreased amyloid beta (1-42) (Abeta42) and increased (phosphorylated) tau in cerebrospinal fluid (CSF) are considered to be a reflection of plaques, tangles, and neuronal degeneration in Alzheimer's disease (AD). Atrophy of the medial temporal lobe (MTA) on magnetic resonance imaging (MRI) reflects neuronal loss in this area.

Objective: To compare diagnostic accuracy of CSF biomarkers and MTA in AD versus controls.

Methods: Abeta42, tau and tau phosphorylated at threonine 181 (Ptau-181) were measured in CSF from 61 AD patients and 32 controls by sandwich enzyme-linked immunosorbent assay. A CSF biomarker profile for AD was constructed. MTA was rated visually on MRI.

Results: When AD patients and controls were evaluated separately, no correlations were present between the CSF markers and MTA score. Both MTA and CSF biomarker profile were independently associated with the diagnosis AD (MTA: OR (95% CI)=28 (3-239); CSF biomarker profile: OR (95% CI)=57 (13-262)). Among individuals younger than 65 years old and without MTA 60% suffered AD, and the finding of an abnormal CSF biomarker profile was limited to AD patients only.

Conclusions: MTA and CSF biomarkers seem to be of incremental value for the diagnosis AD. CSF analysis is most sensitive in the absence of MTA, and especially among early-onset AD patients.