MRI-predicted levels of total tau and beta-amyloid (Aβ) can diagnose Alzheimer’s disease and frontotemporal lobar degeneration with 75% accuracy, researchers reported in the December 26, 2012, online issue of Neurology. The noninvasive procedure could serve as a surrogate for CSF biomarkers obtained through a lumbar puncture.
Corey T. McMillan, PhD, Research Associate in Neurology at the University of Pennsylvania in Philadelphia, and colleagues studied 185 patients with a clinically diagnosed neurodegenerative disease consistent with Alzheimer’s disease or frontotemporal lobar degeneration who had a lumbar puncture and a volumetric MRI. Thirty-two patients had genetic or autopsy-confirmed Alzheimer’s disease or frontotemporal lobar degeneration. The investigators decomposed MRI volumes and used linear regression to predict patients’ CSF total tau and Aβ. They subsequently evaluated the accuracy of MRI-predicted total tau and Aβ using four converging sources, including neuroanatomic visualization and categorization of a subset of patients with genetic or autopsy-confirmed Alzheimer’s disease or frontotemporal lobar degeneration.
“Regression analyses showed that MRI-predicted total tau/Aβ is highly related to actual CSF total tau/Aβ,” said Dr. McMillan. “In each group, both predicted and actual CSF total tau/Aβ have extensively overlapping neuroanatomic correlates,” he added. “MRI may serve as a noninvasive procedure that can screen for Alzheimer’s disease and frontotemporal lobar degeneration pathology as a surrogate for CSF biomarkers.”
“The advantage of the multivariate approach of McMillan et al over previous univariate studies is that these complex MRI patterns can be summarized with a single diagnostically useful value that could potentially be applied in a clinical setting,” said Christian Habeck, PhD, Assistant Professor of Neurology at Columbia University in New York City, and Jennifer L. Whitwell, PhD, of the Department of Radiology at the Mayo Clinic in Rochester, Minnesota, in an accompanying editorial. “One could also see how such a value could aid patient selection for future clinical trials that target these pathologies. However, an empirical test of the total tau/Ab prediction from brain data in an independent sample will be an important additional step before this method could be confidently applied to other cohorts.”