Concordance and Diagnostic Accuracy of [C-11]PIB PET and Cerebrospinal Fluid Biomarkers in a Sample of Patients with Mild Cognitive Impairment and Alzheimer's Disease

• Background: Alzheimer's disease (AD) pathology can be quantified in vivo using cerebrospinal fluid (CSF) levels of amyloid-beta(1-42) (A beta(1-42)), total-tau (t-tau), and phosphorylated tau (p- tau(181p)), as well as with positron emission tomography (PET) using [C-11]Pittsburgh compound-B ([C-11]PIB). Studies assessing concordance between these measures, however, have provided conflicting results. Moreover, it has been proposed that [C-11]PIB PET may be of greater clinical utility in terms of identifying patients with mild cognitive impairment (MCI) who will progress to the dementia phase of AD. Objective: To determine concordance and classification accuracy of CSF biomarkers and [C-11]PIB PET in a cohort of patients with MCI and AD. Methods: 68 patients (MCI, n = 33; AD, n = 35) underwent [C-11]PIB PET and CSF sampling. Cutoffs of >1.41 ([C-11]PIB), <450 pg/mL-and a more lenient cutoff of 550 pg/mL-(A beta(1-42)), <6.5 (A beta(1-42)/p-tau181p), and 1.14 (A beta(1- 42)/t-tau), were used to determine concordance. Logistic regression was used to determine classification accuracy with respect to stable MCI (sMCI) versus MCI who progressed to AD (pMCI). Results: Concordance between [C-11]PIB and A beta(1-42) was highest for sMCI (67%), followed by AD (60%) and pMCI (33%). Agreement was increased across groups using A beta(1-42) < 550 pg/mL, or A beta(1-42) to tau ratios. Logistic regression showed that classification accuracy of [11C] PIB, between sMCI and pMCI, was superior to A beta(1-42) (73% versus 58%), A beta(1-42)/t-tau (63%), and A beta(1-42)/p-tau181p (65%). Conclusion: In the present study, [C-11]PIB proved a better predictor of progression to AD in patients with MCI, relative to CSF measures of A beta(1-42) or A beta(1-42)/tau. Discordance between PET and CSF markers for A beta(1-42) suggests they cannot be used interchangeably, as is currently the case.

Subject headings

SAMHÄLLSVETENSKAP  -- Psykologi (hsv//swe)

SOCIAL SCIENCES  -- Psychology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Neurovetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Neurosciences (hsv//eng)

Keyword

[C-11]PIB

Alzheimer's disease

amyloid

cerebrospinal fluid

mild cognitive impairment

positron emission tomography

tau

Publication and Content Type

ref (subject category)

art (subject category)