Biomedical subjects

Giuseppe Iannucci

Publications and source records attributed to Giuseppe Iannucci.

8 recordsLinked to original sources

PubMed2005

Progressive gray matter damage in patients with relapsing-remitting multiple sclerosis: a longitudinal diffusion tensor magnetic resonance imaging study.

BACKGROUND: Diffusion tensor magnetic resonance imaging (DT MRI) has the potential to provide in vivo information about tissue microstructure. In multiple sclerosis (MS), DT MRI has disclosed the presence of occult structural damage in the normal-appearing brain tissues. OBJECTIVE: To investigate whether DT MRI is sensitive to longitudinal changes of brain damage that may occur beyond the resolution of T2-weighted images in patients with relapsing-remitting MS. DESIGN: Twenty-six untreated patients with relapsing-remitting MS were followed up for 18 months. Dual-echo, DT and postcontrast T1-weighted MRIs of the brain were obtained at baseline and then every 3 months. Mean diffusivity (D) histograms of normal-appearing gray (GM) and white matter were produced. Total T2-hyperintense and T1-hypointense lesion volumes; normalized whole brain tissue, GM, and white matter volumes; percentage brain volume change between the study entry and exit images; average lesion D; and fractional anisotropy were also calculated. RESULTS: During the study period, a significant decrease of normalized whole brain tissue, average lesion fractional anisotropy and normal-appearing GM D histogram peak height, and a significant increase of average normal-appearing GM D and T2-hyperintense lesion volumes were observed. Changes of normal-appearing GM diffusivity were independent of the concomitant changes of normalized whole brain tissue and GM volumes. CONCLUSIONS: The DT MRI findings show progressive microstructural changes in the normal-appearing GM of patients with untreated relapsing-remitting MS. Such changes do not reflect a concomitant development of brain atrophy and confirm the importance of GM pathology in MS.

Adult↗

PubMed2004

European study on intravenous immunoglobulin in multiple sclerosis: results of magnetization transfer magnetic resonance imaging analysis.

BACKGROUND: Magnetization transfer magnetic resonance imaging (MT MRI) can provide in vivo markers reflecting the severity of multiple sclerosis-related brain damage occurring within and outside T2-visible lesions. OBJECTIVE: To investigate the effect of intravenous immunoglobulin (IVIG) treatment on the accumulation of brain damage in patients with secondary progressive multiple sclerosis (SPMS), measured using MT MRI.Design, Patients, and Intervention Seventy patients with SPMS participating in the European, multicenter, randomized, double-blind, placebo-controlled trial of IVIG in SPMS underwent brain T2-weighted and MT MRI at baseline and after 12 and 24 months. The MT MRI scans were post-processed and analyzed to obtain MT ratio values from T2-visible lesions and MT ratio histograms from the normal-appearing brain tissue (NABT). RESULTS: At baseline, a significant difference was found for NABT MT ratio histogram peak height (P =.003) between treated patients and patients receiving placebo. No significant differences between treated patients and those receiving placebo were found for any of the considered MT MRI-derived metrics in terms of treatment x time interaction. Nevertheless, over the 24-month period, the placebo patients experienced a 6.75% reduction of the NABT MT ratio histogram peak height, whereas treated patients experienced only a 0.92% reduction of the NABT MT ratio histogram peak height. CONCLUSIONS: This study did not show any statistically significant effect of IVIG on MT MRI quantities. Nevertheless, the markedly different percentage change of the NABT MT ratio histogram peak height over time between patients receiving placebo and treated patients suggests a possible role of IVIG treatment in preventing the loss of "truly" normal brain tissue in SPMS patients.

Brain↗

PubMed2003

Age-related changes in conventional, magnetization transfer, and diffusion-tensor MR imaging findings: study with whole-brain tissue histogram analysis.

PURPOSE: To investigate the influence of aging on conventional magnetic resonance (MR) imaging-, magnetization transfer MR imaging-, and diffusion-tensor MR imaging-derived measurements. MATERIALS AND METHODS: Dual-echo T1-weighted magnetization transfer and diffusion-tensor MR images of the brain were obtained in 89 healthy subjects. Normalized brain parenchymal volume (NBV) was measured by using a fully automated technique. Magnetization transfer ratio (MTR), apparent diffusion coefficient (ADC), and fractional anisotropy (FA) histograms were created for the whole brain (MTR values) or for a large representative portion of it (ADC and FA values). Bivariate correlations were assessed by using the Spearman rank correlation coefficient. A stepwise selection procedure was used to identify the combination of variables that were most influenced by subject age in a multivariate regression model. RESULTS: Significant correlations were found between subject age and the following variables: number of hyperintense areas in the brain at T2-weighted MR imaging (r = 0.63, P <.001), NBV (r = -0.79, P <.001), mean ADC (r = 0.34, P =.001), ADC peak height (r = -0.34, P =.001), and FA peak height (r = -0.57, P <.001). NBV correlated significantly with number of hyperintense areas (P <.001), MTR peak height (P <.001), mean ADC (P =.001), ADC peak height (P =.001), and FA peak height (P <.001). The final multivariable regression model included NBV and number of hyperintense areas at T2-weighted MR imaging as independent predictors of subject age. CONCLUSION: In addition to the extent of T2-weighted MR imaging hyperintense areas and the measurement of NBV, diffusion-tensor MR imaging provides additional in vivo information about microstructural age-related brain tissue changes.

Adult↗

PubMed2003

Occult tissue damage in patients with primary progressive multiple sclerosis is independent of T2-visible lesions--a diffusion tensor MR study.

Although quantitative magnetic resonance (MR) studies have shown that primary progressive multiple sclerosis (PPMS) patients have subtle and diffuse changes of the normal-appearing brain tissue (NABT), the nature of these changes is still poorly understood. The aim of this study was to improve our understanding of the NABT damage in PPMS patients by comparing diffusion tensor magnetic resonance (DT MR) quantities of a large portion of the brain from these patients with those from healthy subjects with and without T2-visible lesions. Dual-echo and DT MR images of the brain were obtained from 20 patients with PPMS, 20 age- and gender-matched healthy volunteers with normal conventional MR scans of the brain, and 20 age-, gender- and T2 lesion volume-matched healthy subjects. Mean diffusivity (MD) and fractional anisotropy (FA) histograms of the NABT were derived from all the individuals. Average lesion MD and FA were calculated in PPMS patients and healthy controls with T2-visible lesions. MD and FA histogram-derived metrics of the NABT from PPMS patients differed significantly from the corresponding quantities from healthy volunteers with no brain T2-visible lesions and from those from healthy volunteers with overt brain MR abnormalities (p values ranging from < 0.0001 to 0.01). Average lesion MD was also significantly higher in PPMS patients than in healthy volunteers with T2-visible lesions (p = 0.03). In PPMS patients, no significant correlation was found between any of the DT MR quantities of NABT damage and a) the T2 lesion volume, b) the average lesion MD, and c) the normalized brain volume. This study shows that in PPMS patients there is a significant microscopic damage of the NABT which is independent of the extent of T2-visible abnormalities. This suggests that Wallerian degeneration of fibers passing through macroscopic abnormalities is not a major factor contributing to diffuse NABT pathology of these patients.

Adult↗

PubMed2002

Cognitive dysfunction in patients with mildly disabling relapsing-remitting multiple sclerosis: an exploratory study with diffusion tensor MR imaging.

Previous studies assessing the magnetic resonance imaging (MRI) correlates of cognitive dysfunction in multiple sclerosis (MS) achieved conflicting results. Diffusion tensor (DT)-MRI provides metrics that are sensitive to the macro- and microscopic MS lesion load with increased specificity to the more destructive aspects of MS pathology than conventional imaging. We performed an exploratory study to assess the magnitude of the correlation between quantities derived from DT-MRI and measures of cognitive impairment in patients with relapsing-remitting (RR) MS.T2, T1, DT-MRI scans of the brain and an extensive battery of neuropsychological tests (exploring language, complex reasoning, attention and memory) were obtained from 34 RRMS patients. We measured T2 and T1 lesion volumes (LV) and brain volume. Average lesion mean diffusivity (D) and fractional anisotropy (FA) were calculated. D and FA histograms from the brain tissue (BT), the normal-appearing brain tissue (NABT), the normal-appearing white matter (NAWM) and the normal-appearing gray matter (NAGM) were also obtained. Nine patients (26.5%) were found to be cognitively impaired. Moderate correlations were found between symbol digit modalities test, verbal fluency test and 10/36 spatial recall test scores and T2 LV, T1 LV and average lesion, WBT, NABT, NAWM and NAGM values (r values ranging from -0.30 to -0.53). No correlations were found between any of the neuropsychological test scores and brain volume, average lesion FA and WBT FA.DT-MRI provides quantitative metrics that seem to reflect the severity of language, attention and memory deficits in patients with RRMS. This study also suggests that the extent and the intrinsic nature of the macroscopic lesions as well as the damage of the NAWM and NAGM all contribute to the neuropsychological deficits of RRMS patients.

Adult↗

PubMed2002

Assessment of normal-appearing white and gray matter in patients with primary progressive multiple sclerosis: a diffusion-tensor magnetic resonance imaging study.

BACKGROUND: Diffusion-tensor magnetic resonance imaging is sensitive to the more destructive aspects of multiple sclerosis (MS) evolution occurring outside and within T2-visible lesions and, as a consequence, holds promise for providing a more complete picture of primary progressive (PP) MS-related tissue damage than conventional magnetic resonance imaging. OBJECTIVE: To improve our understanding of PPMS by assessing the extent of occult pathological features in the normal-appearing white and gray matter of the brain using diffusion-tensor magnetic resonance imaging. METHODS: Ninety-six patients with PPMS, 47 patients with secondary progressive (SP) MS, and 44 healthy control subjects were studied. T2-hyperintense and T1-hypointense lesion volumes were calculated, and the volume of the whole brain tissue was measured. Diffusion-tensor magnetic resonance imaging scans were postprocessed and analyzed to obtain the mean diffusivity and fractional anisotropy histograms from the brain and from the normal-appearing white and gray matter in isolation. RESULTS: The mean T2-hyperintense and T1-hypointense lesion volumes were lower in patients with PPMS than in patients with SPMS, while the mean absolute brain volumes were similar in the 2 groups. The average lesion diffusivity was significantly higher in patients with SPMS than in patients with PPMS (P<.001). Histogram-derived metrics of the brain tissue and normal-appearing white and gray matter were significantly different between patients with PPMS and healthy subjects (range, P =.004 to <.001). Average diffusivity values were significantly higher in patients with SPMS than in patients with PPMS for all the tissues studied (range, P =.001 to <.001). Fractional anisotropy histogram-derived quantities did not significantly differ between the 2 patient groups (range, P =.94 to.03). CONCLUSION: This study confirms that, in patients with PPMS, normal-appearing white and gray matter are not spared by disease-related pathological processes, although they are affected to a lesser degree than in patients with SPMS.

Adult↗

PubMed2002

MR correlates of cerebral atrophy in patients with multiple sclerosis.

OBJECTIVE: To investigate the in-vivo correlates of brain atrophy in patients with multiple sclerosis (MS) by assessing the relationship between normalized measures of brain volume (NBV) and other magnetic resonance (MR) measures of tissue damage. BACKGROUND: Brain atrophy diffusely occurs and progressively increases in patients with MS. Nevertheless, the mechanisms leading to brain atrophy in this disease are not fully understood. METHODS: MR examinations were performed in 20 patients with relapsing-remitting MS. Conventional MRI was used to assess NBV and total brain T2-hyperintense and T1-hypointense lesion volumes. Proton MR spectroscopic imaging and diffusion tensor MR imaging were also performed for large portions of brain containing mainly normal-appearing tissue to provide indices of tissue damage, including N-acetylaspartate to creatine ratio (NAA/Cr) and mean diffusivity (D). RESULTS: Values of NBV correlated significantly with those of average brain (r = -0.58, p = 0.007) and NAA/Cr (r = 0.67, p < 0.001). The relationship of these markers of tissue damage to NBV was also found when NAA/Cr and were computed together in a composite MR score (r = 0.70, p < 0.001). In contrast, NBV values did not correlate with measurements of average lesion, T(2) and T(1) weighted total brain MRI lesion volumes. CONCLUSIONS: This study suggests that brain atrophy in MS is not simply due to axonal loss, but rather reflects a more generalized process that involves various brain tissue components. Damage to the normal-appearing tissue rather than the extent and intrinsic pathology of macroscopic lesions seems to be important in the destructive process leading to MS-related irreversible cerebral atrophy.

Adult↗

PubMed2002

Magnetization transfer and diffusion tensor MR imaging of acute disseminated encephalomyelitis.

BACKGROUND AND PURPOSE: Patients with acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS) have a similar pattern of abnormalities on conventional MR images. We used magnetization transfer and diffusion tensor MR imaging to quantify normal-appearing brain tissue and cervical cord disease in patients with ADEM and to compare findings with those in healthy volunteers and patients with MS. METHODS: Brain dual-echo, T1-weighted magnetization transfer, and diffusion tensor images were obtained in eight patients with ADEM, in 10 patients with MS, and in 10 healthy volunteers. Fast short-tau inversion recovery, T1-weighted, and magnetization transfer cervical cord images were also obtained. We identified lesions on the images and quantified their volumes. We performed histogram analysis of the magnetization transfer ratio (MTR) and average mean histogram analysis of the diffusivity (D) in normal-appearing brain tissue and MTR in the cervical cord. RESULTS: Histogram analysis of normal-appearing brain tissue in patients with MS showed significantly lower MTRs and peak positions and significantly higher D averages compared with those in patients with ADEM. Patients with MS had significantly lower MTRs and D peak heights and significantly higher average D compared with those in healthy volunteers. Between patients with ADEM and control subjects, normal-appearing brain tissue MTR and D histogram metrics did not differ significantly. Cervical cord MTRs did not differ between control subjects and patients with ADEM, whereas the average MTR and histogram peak position was significantly lower in patients with MS than in the other groups. CONCLUSION: Outside the acute phase of disease and as opposed to what happens in MS, the normal-appearing brain tissue and cervical cord in patients with ADEM are spared in the pathologic process.

Adult↗