Roberta Riello

Brain volumes in healthy adults aged 40 years and over: a voxel-based morphometry study.

Background and aims: Gender and age effect on brain morphology have been extensively investigated. However, the great variety in methods applied to morphology partly explain the conflicting results of linear patterns of tissue changes and lateral asymmetry in men and women. The aim of the present study was to assess the effect of age, gender and laterality on the volumes of gray matter (GM) and white matter (WM) in a large group of healthy adults by means of voxel-based morphometry. This technique, based on observer-independent algorithms, automatically segments the 3 types of tissue and computes the amount of tissue in each single voxel. Methods: Subjects were 229 healthy subjects of 40 years of age or older, who underwent magnetic resonance (MR) for reasons other than cognitive impairment. MR images were reoriented following the AC-PC line and, after removing the voxels below the cerebellum, were processed by Statistical Parametric Mapping (SPM99). GM and WM volumes were normalized for intracranial volume. Results: Women had more fractional GM and WM volumes than men. Age was negatively correlated with both fractional GM and WM, and a gender × age interaction effect was found for WM, men having greater WM loss with advancing age. Pairwise differences between left and right GM were negative (greater GM in right hemisphere) in men, and positive (greater GM in left hemisphere) in women (−0.56±4.2 vs 0.99±4.8; p=0.019). Conclusions: These results support side-specific accelerated WM loss in men, and may help our better understanding of changes in regional brain structures associated with pathological aging.

Prescription and choice of diagnostic imaging by physician specialty in Alzheimer’s Centers (Unità di Valutazione Alzheimer — UVA) in Northern Italy

Background and aims: Physician’s specialty has been shown to have an effect on health outcomes and financial expenditure in a number of conditions. This is particularly true in the differential diagnosis of cognitive deterioration, in which technological procedures are needed. The aim of this study is to assess the effect of physician specialty on the prescription of diagnostic imaging (CT and MR) in patients with cognitive impairment, referred to Alzheimer Evaluation Units (Unità di Valutazione Alzheimer] in Northern Italy. Methods: An ad-hoc questionnaire was sent to UVA referents in northern Italy (Lombardy, Piedmont, Trentino, Emilia-Romagna and Veneto), requesting information on the frequency of prescriptions for CT and MR and reasons for the choice, on a 0 to 7 scale. Results: The physician-in-charge was a neurologist in 22 and a geriatrician in 22 Alzheimer’s centers. Intensive use of CT was similar in neurologists and geriatricians (64 vs 68%], whereas intensive use of MR was more frequent in neurologists (41 vs 10%; p=0.03). Overall, organizational factors (availability of the scanner on-site and waiting list for imaging, mean weight=1.6±1.4) were as important as patient-related factors (age, severity of cognitive impairment, and clinical suspicion of cerebrovascular disease, mean weight 1.1±1.4; p=0.84). Sixty-five percent of neurologists based their choices between CT and MR on patient-related and 35% on organizational factors, whereas the opposite proportion was found for geriatricians (29 vs 71%, p=0.04). Conclusions: The high weight of organizational factors on the prescription of diagnostic imaging is not consistent with an evidence-based diagnostic system.