The Italian Alzheimer's Disease Neuroimaging Initiative (I-ADNI): validation of structural MR imaging.

BACKGROUND: The North American Alzheimer's Disease Neuroimaging Initiative (NA-ADNI) was the first program to develop standardized procedures for Alzheimer's disease (AD) imaging biomarker collection. OBJECTIVE: We describe the validation of acquisition and processing of structural magnetic resonance imaging (MRI) in different Italian academic AD clinics following NA-ADNI procedures. METHODS: 373 patients with subjective memory impairment (n = 12), mild cognitive impairment (n = 92), Alzheimer's dementia (n = 253), and frontotemporal dementia (n = 16) were enrolled in 9 Italian centers. 22 cognitively healthy elderly controls were also included. MRI site qualification and MP-RAGE quality assessment was applied following the NA-ADNI procedures. Indices of validity were: (i) NA-ADNI phantom's signal-to-noise and contrast-to-noise ratio, (ii) proportion of images passing quality control, (iii) comparability of automated intracranial volume (ICV) estimates across scanners, and (iv) known-group validity of manual hippocampal volumetry. RESULTS: Results on Phantom and Volunteers scans showed that I-ADNI acquisition parameters were comparable with those one of the ranked-A ADNI scans. Eighty-seven percent of I-ADNI MPRAGE images were ranked of high quality in comparison of 69% of NA-ADNI. ICV showed homogeneous variances across scanners except for Siemens scanners at 3.0 Tesla (p = 0.039). A significant difference in hippocampal volume was found between AD and controls on 1.5 Tesla scans (p < 0.001), confirming known group validity test. CONCLUSION: This study has provided standardization of MRI acquisition and imaging marker collection across different Italian clinical units and equipment. This is a mandatory step to the implementation of imaging biomarkers in clinical routine for early and differential diagnosis.

Micro-Raman study of copper hydroxychlorides and other corrosion products of bronze samples mimicking archaeological coins.

Three bronze samples created by CNR-ISMN (National Research Council-Institute of Nanostructured Materials) to be similar to Punic and Roman coins found in Tharros (OR, Sardinia, Italy) were studied to identify the corrosion products on their surfaces and to evaluate the reliability of the reproduction process. Micro-Raman spectroscopy was chosen to investigate the corroded surfaces because it is a non-destructive technique, it has high spatial resolution, and it gives the opportunity to discriminate between polymorphs and to correlate colour and chemical composition. A significant amount of green copper hydroxychlorides (Cu(2)(OH)(3)Cl) was detected on all the coins. Their discrimination by Raman spectroscopy was challenging because the literature on the topic is currently confusing. Thus, it was necessary to determine the characteristic peaks of atacamite, clinoatacamite, and the recently discovered anatacamite by acquiring Raman spectra of comparable natural mineral samples. Clinoatacamite, with different degrees of order in its structure, was the major component identified on the three coins. The most widespread corrosion product, besides hydroxychlorides, was the red copper oxide cuprite (Cu(2)O). Other corrosion products of the elements of the alloy (laurionite, plumbonacrite, zinc carbonate) and those resulting from burial in the soil (anatase, calcite, hematite) were also found. This study shows that identification of corrosion products, including discrimination of copper hydroxychlorides, could be accomplished by micro-Raman on valuable objects, for example archaeological findings or works of art, avoiding any damage because of extraction of samples or the use of a destructive analytical technique.

DTI of trabecular bone marrow.

The development of NMR diffusion imaging and diffusion tensor imaging (DTI) has offered the possibility of studying the porous structures beyond anatomical imaging. In fact, random molecular motions, within tissue components, probe tissue microstructures. Up to now, the DTI method was mainly used to investigate cerebral morphology and study white matter diseases. In this study, it has been applied to trabecular bone marrow analysis to obtain structural information on spongy bone tissue. Our first results show that DTI could represent an important tool in studying the microstructural architecture of the trabecular bone as well as the microarchitecture of porous media.

The influence of superplasticizers on the first steps of tricalcium silicate hydration studied by NMR techniques.

The influence of superplasticizer sulfonated naphthalene formaldehyde (SNF) on the hydration process of tricalcium silicate (C3S) paste was investigated by (1)H nuclear magnetic resonance spin-spin and spin lattice relaxation times. The addition of SNF superplasticizer to C3S paste clearly affects the morphology and growth rates of the hydration products, mainly by increasing the dormant period length, which lasts for several hours more than in conventional C3S hydrated paste, while reducing the acceleration period length. The relaxation data indicated that a pronounced delay occurs in the C3S hardening when sulfonated polymers are added to the makeup water. For all the analyzed samples, prepared with a water-to-C3S ratio of 0.4, the decay of the echo magnetization has been fitted by adopting both a monoexponential and a biexponential relaxation model in order to evaluate the contributions from water in different regimes of hydration.