Evaluation of the severity of chronic hepatitis C with 3-T 1H-MR spectroscopy

OBJECTIVE. The purpose of this study was to compare the spectral characteristics of lipids, choline-containing compounds, and glutamine-glutamate complex assessed with H-1-MR spectroscopy with the histologic findings in patients with chronic hepatitis C. SUBJECTS AND METHODS. Nine healthy controls and 30 patients with biopsy-proven hepatitis C virus-related liver disease participated in this prospective study. Degree of fibrosis and histologic activity were scored according to the METAVIR classification. The percentage of involved hepatocytes was used to grade steatosis. Hepatic spectra were obtained with a 3-T spectroscopic system. Tenfold cross-validated stepwise discriminant analysis was performed to classify disease severity on the basis of the spectroscopic findings. RESULTS. There was a strong correlation between H-1-MR spectroscopically measured lipid concentration and the degree of steatosis at histologic examination (r=0.9236, p < 0.0001). This finding enabled clear separation of groups according to degree of histologically determined steatosis. Variation in lipid concentration was consistent with the degree of steatosis (r=0.7265, p < 0.0001) and stage of fibrosis (r=0.8156, p < 0.0001). In univariate analysis, concentrations of both choline-containing compounds and glutamine-glutamate complex had a direct correlation with histologic grade ( p < 0.0001) and degree of steatosis ( p < 0.0001) but not with stage of fibrosis ( p > 0.05). In multivariate analysis, the only factor independently associated with concentrations of choline-containing compounds and glutamine-glutamate complex was histologic grade. In cross-validated discriminant analysis based on choline-containing compound, glutamine-glutamate complex, and lipid resonance, 70% ( 21 of 30) of the histologic grade groups and 73% (22 of 30) of the steatosis groups were correctly classified. CONCLUSION. Hydrogen-1 MR spectroscopy can be an alternative to liver biopsy in the evaluation of steatosis and necroinflammatory activity in liver disease but is not useful for complete evaluation of hepatic fibrosis

Follow-Up of Coiled Cerebral Aneurysms at 3T: Comparison of 3D Time-of-Flight MR Angiography and Contrast-Enhanced MR Angiography

BACKGROUND AND PURPOSE: Our aim was to compare contrast-enhanced MR angiography (CE-MRA) and 3D time-of-flight (TOF) MRA at 3T for follow-up of coiled cerebral aneurysms. MATERIALS AND METHODS: Fifty-two patients treated with Guglielmi detachable coils for 54 cerebral aneurysms were evaluated at 3T MRA. 3D TOF MRA (TR/TE = 23/3.5; SENSE factor = 2.5) and CE-MRA by using a 3D ultrafast gradient-echo sequence (TR/TE = 5.9/1.8; SENSE factor = 3) enhanced with 0.1-mmol/kg gadobenate dimeglumine were performed in the same session. Source images, 3D maximum intensity projection, 3D shaded surface display, and/or 3D volume-rendered reconstructions were evaluated in terms of aneurysm occlusion/patency and artifact presence. RESULTS: In terms of clinical classification, the 2 MRA sequences were equivalent for 53 of the 54 treated aneurysms: 21 were considered fully occluded, whereas 16 were considered to have a residual neck and 16 were considered residually patent at follow-up MRA. The remaining aneurysm appeared fully occluded at TOF MRA but had a residual patent neck at CE-MRA. Visualization of residual aneurysm patency was significantly ( P = .001) better with CE-MRA compared with TOF MRA for 10 (31.3%) of the 32 treated aneurysms considered residually patent with both sequences. Coil artifacts were present in 5 cases at TOF MRA but in none at CE-MRA. No relationship was apparent between the visualization of patency and either the size of the aneurysm or the interval between embolization and follow-up. CONCLUSION: At follow-up MRA at 3T, unenhanced TOF and CE-MRA sequences are similarly effective at classifying coiled aneurysms as occluded or residually patent. However, CE-MRA is superior to TOF MRA for visualization of residual patency and is associated with fewer artifacts

In vivo Diffusion Tensor Magnetic Resonance Tractography of the Sheep Brain : An Atlas of the Ovine White Matter Fiber Bundles

Diffusion Tensor Magnetic Resonance Imaging (DTI) allows to decode the mobility of water molecules in cerebral tissue, which is highly directional along myelinated fibers. By integrating the direction of highest water diffusion through the tissue, DTI Tractography enables a non-invasive dissection of brain fiber bundles. As such, this technique is a unique probe for in vivo characterization of white matter architecture. Unraveling the principal brain texture features of preclinical models that are advantageously exploited in experimental neuroscience is crucial to correctly evaluate investigational findings and to correlate them with real clinical scenarios. Although structurally similar to the human brain, the gyrencephalic ovine model has not yet been characterized by a systematic DTI study. Here we present the first in vivo sheep (ovis aries) tractography atlas, where the course of the main white matter fiber bundles of the ovine brain has been reconstructed. In the context of the EU's Horizon EDEN2020 project, in vivo brain MRI protocol for ovine animal models was optimized on a 1.5T scanner. High resolution conventional MRI scans and DTI sequences (b-value = 1,000 s/mm2, 15 directions) were acquired on ten anesthetized sheep o. aries, in order to define the diffusion features of normal adult ovine brain tissue. Topography of the ovine cortex was studied and DTI maps were derived, to perform DTI tractography reconstruction of the corticospinal tract, corpus callosum, fornix, visual pathway, and occipitofrontal fascicle, bilaterally for all the animals. Binary masks of the tracts were then coregistered and reported in the space of a standard stereotaxic ovine reference system, to demonstrate the consistency of the fiber bundles and the minimal inter-subject variability in a unique tractography atlas. Our results determine the feasibility of a protocol to perform in vivo DTI tractography of the sheep, providing a reliable reconstruction and 3D rendering of major ovine fiber tracts underlying different neurological functions. Estimation of fiber directions and interactions would lead to a more comprehensive understanding of the sheep's brain anatomy, potentially exploitable in preclinical experiments, thus representing a precious tool for veterinaries and researchers

Non-HDL cholesterol predicts coronary heart disease in primary prevention: findings from an Italian a 40-69 year-old cohort in general practice

Scopo. La frazione lipoproteica denominata “colesterolo non-HDL” viene raccomandata come un indice di rischio coronarico (RC) associata alla dislipidemia combinata ed è stata trovata un utile fattore predittivo del rischio coronarico nei pazienti diabetici. Abbiamo studiato l’associazione tra i fattori di RC noti, incluso la colesterolo non-HDL ed una “condizione di RC elevato”, cioè un “RC a 5-anni >15%” in medicina generale. Metodi. Abbiamo studiato 4085 individui di età 40-69 anni, 489 diabetici e 3596 non-diabetici, appartenenti ad una coorte opportunistica. Sono state utilizzate le statistiche descrittive, e la regressione logistica multivariata aggiustata per età e sesso per i confronti tra i 2 gruppi. Risultati. Circa il 12% dei participanti era diabetico. I confronti aggiustati per età e sesso hanno mostrato che tutte le variabili erano significativamente peggiori nei diabetici rispetto ai non-diabetici (eccetto fumo, colesterolo totale e rapporto colesterolo totale/HDL). I diabetici avevano un “RC medio a 5-anni” più alto dei non-diabetici (18.8±11.9% vs 7.5±6.9%, P15%” (55.4% vs 11.1%, P<0.01). Nei diabetici, le variabili associate ad una “condizione di RC elevato” sono: fumo, pressione arteriosa sistolica (PAS) e colesterolemia non-HDL; nei non-diabetici: fumo, PAS, colesterolemia non-HDL e HDL (inversamente). Conclusioni. Il colesterolo non-HDL – oltre a fumo e PAS – è un forte predittore di una “condizione di RC elevato” sia negli individui diabetici che non-diabetici

CSF β-amyloid and white matter damage: a new perspective on Alzheimer's disease

Objective: To assess the connection between amyloid pathology and white matter (WM) macro- and micro-structural damage in demented patients compared with controls. Methods: Eighty-five participants were recruited: 65 with newly diagnosed Alzheimer’s disease (AD), non-AD dementia or mild cognitive impairment (MCI), and 20 age- and sex-matched heatlhy controls. β-amyloid1-42 (Aβ) levels were determined in cerebrospinal fluid (CSF) samples from all patients and 5 controls. Among patients, 42 had pathological CSF Aβ levels (Aβ+), while 23 had normal CSF Aβ levels (Aβ-). All participants underwent neurological examination, neuropsychological testing and brain magnetic resonance imaging (MRI). We used T2-weighted scans to quantify white matter (WM) lesion loads (LL), and diffusion weighted images (DWI) to assess their microstructural substrate. Non-parametric statistical tests were used for between-group comparisons and multiple regression analyses. Results: We found an increased WM-LL in Aβ(+) compared to both, healthy controls (p=0.003) and Aβ(-) patients (p=0.02). Interestingly, CSF Aβ concentration was the best predictor patients’ WM-LL (r=-0.30, p<0.05) when using age as a covariate. Lesion apparent diffusion coefficient (ADC) value was higher in all patients than in controls (p=0.0001), and correlated with WM-LL (r=0.41, p=0.001). In Aβ(+), WM-LL correlated with WM microstructural damage in the left peritrigonal WM (p<0.0001). Conclusions: WM damage is crucial in Alzheimer’s disease (AD) pathogenesis. The correlation between CSF Aβ levels and WM-LL suggests a direct link between amyloid pathology and WM macro- and microstructural damage

Biblioteca Universale Rizzoli : 60 anni in 367 copertine

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