Evaluation of the Posterior Cingulate Region with FDG-PET and Advanced MR Techniques in Patients with Amnestic Mild Cognitive Impairment: Comparison of the Methods
Affiliations: [a] Department of General and Interventional Radiology and Neuroradiology, Wroclaw Medical University, Wroclaw, Poland | [b] Department of Nuclear Medicine, 4th Military Hospital, Wroclaw, Poland | [c] Department of Psychiatry, Wroclaw Medical University, Wroclaw, Poland | [d] Department of Pathophysiology, Wroclaw Medical University, Wroclaw, Poland | [e] Euromedic Wroclaw PET/CT Medical Center, Wroclaw, Poland
Correspondence:
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Correspondence to: Anna Zimny, Department of General and Interventional Radiology and Neuroradiology, Wroclaw Medical University, ul. Borowska 213, 50-556 Wroclaw, Poland. Tel.: +48 71 733 1660; Fax: +48 71 733 1689; E-mail: [email protected].
Abstract: Background:The posterior cingulate region is an area of the earliest pathological changes in amnestic mild cognitive impairment (aMCI). The utility of FDG-PET imaging in dementia is already well established. Objectives:The aim of the study was to compare FDG-PET with advanced MR measurements: MR spectroscopy (MRS), perfusion weighted imaging (PWI), and diffusion tensor imaging (DTI) within the posterior cingulate region in patients with aMCI. Methods:Fifty-five patients diagnosed with aMCI (66.5 y) and 20 age-matched controls (69 y) underwent MR examination including MRS, PWI, and DTI followed by FDG-PET scanning. Values of MRS metabolite ratios (NAA/Cr, Cho/Cr, mI/Cr), PWI cerebral blood volume (rCBV), and DTI fractional anisotropy (FA) were compared to the FDG-PET rates of glucose metabolism. Results:Compared to controls, aMCI patients showed significant (p < 0.05) glucose hypometabolism, and lower rCBV and FA values. FDG-PET results correlated significantly with rCBV values. Compared to FDG-PET, PWI showed similar and DTI greater accuracy in distinguishing aMCI from controls. According to FDG-PET findings, two groups of aMCI patients were established: those with lower (PET-positive) and normal (PET-negative) glucose uptake. PET-positive aMCI subjects showed normal MRS findings, lower rCBV and FA values, while PET-negative patients revealed normal MRS and PWI results but significantly lower FA values. Conclusions:Advanced MR techniques such as PWI and particularly DTI may be regarded as competitive techniques to FDG-PET. DTI was the only method to show alterations in aMCI patients with normal FDG-PET, PWI, and MRS findings. DTI seems to be a very sensitive biomarker of early degeneration in aMCI.
