title: Magnetic resonance spectroscopy and brain volumetry in mild cognitive impairment. A prospective study.
abstract: To assess the accuracy of magnetic resonance spectroscopy (1H-MRS) and brain volumetry in mild cognitive impairment (MCI) to predict conversion to probable Alzheimer's disease (AD).
  
  
  
  Forty-eight patients fulfilling the criteria of amnestic MCI who underwent a conventional magnetic resonance imaging (MRI) followed by MRS, and T1-3D on 1.5 Tesla MR unit. At baseline the patients underwent neuropsychological examination. 1H-MRS of the brain was carried out by exploring the left medial occipital lobe and ventral posterior cingulated cortex (vPCC) using the LCModel software. A high resolution T1-3D sequence was acquired to carry out the volumetric measurement. A cortical and subcortical parcellation strategy was used to obtain the volumes of each area within the brain. The patients were followed up to detect conversion to probable AD.
  
  
  
  After a 3-year follow-up, 15 (31.2%) patients converted to AD. The myo-inositol in the occipital cortex and glutamate+glutamine (Glx) in the posterior cingulate cortex predicted conversion to probable AD at 46.1% sensitivity and 90.6% specificity. The positive predictive value was 66.7%, and the negative predictive value was 80.6%, with an overall cross-validated classification accuracy of 77.8%. The volume of the third ventricle, the total white matter and entorhinal cortex predict conversion to probable AD at 46.7% sensitivity and 90.9% specificity. The positive predictive value was 70%, and the negative predictive value was 78.9%, with an overall cross-validated classification accuracy of 77.1%. Combining volumetric measures in addition to the MRS measures the prediction to probable AD has a 38.5% sensitivity and 87.5% specificity, with a positive predictive value of 55.6%, a negative predictive value of 77.8% and an overall accuracy of 73.3%.
  
  
  
  Either MRS or brain volumetric measures are markers separately of cognitive decline and may serve as a noninvasive tool to monitor cognitive changes and progression to dementia in patients with amnestic MCI, but the results do not support the routine use in the clinical settings.
authors.affiliation: Radiology Department, Quirón Hospital, Zaragoza 50009, Spain.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Fayed
authors.affiliation: Department of Neurology, Miguel Servet Hospital, Zaragoza 50009, Spain. Electronic address: pmodrego@salud.aragon.es.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Modrego
authors.affiliation: Biomedical Engineering, Quirón Hospital, Valencia, Spain; CIBERSAM, Mental Research Network, Valencia, Spain.
authors.forename: Gracián
authors.initials: G
authors.lastname: García-Martí
authors.affiliation: Biomedical Engineering, Quirón Hospital, Valencia 46920, Spain.
authors.forename: Roberto
authors.initials: R
authors.lastname: Sanz-Requena
authors.affiliation: Radiology Department, Quirón Hospital, Valencia 46920, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Marti-Bonmatí
mesh_terms: D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology*; D001931:Brain Mapping / Q000379:methods; D060825:Cognitive Dysfunction / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D009929:Organ Size; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Alzheimer's disease; Brain volumetry; Magnetic resonance spectroscopy; Mild cognitive impairment