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

Background Decreased amyloid β (1-42) (Aβ42) 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 Aβ42, 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.