Liver contrast enhanced ultrasound perfusion imaging in the evaluation of chronic hepatitis C fibrosis: preliminary results

We wanted to determine whether liver contrast-enhanced ultrasound (CEUS)–derived peak signal intensity (PSI) and peak signal intensity/time (PIT) predict liver fibrosis in chronic hepatitis C (CHC). Fortynine patients with CHC (METAVIR classification) and 10 control subjects were included in the study. After a bolus of 2.4 mL SonoVue (Bracco Imaging, Milan, Italy) solution was injected into a peripheral vein, the right lobe of the liver containing the right portal vein was scanned in a transverse section. Two-dimensional sonography was performed using the Philips iU22 ultrasound system (Philips Healthcare, Best, the Netherlands). A 1.0–5.0-MHz (C5-1) wideband convex transducer was used, applying the following settings in all cases. Regions of interest were manually drawn over the right liver lobe and over the portal vein (PV). Liver parenchyma PSI (LPpsi) and PIT (LPpit), portal vein PSI (PVpsi) and PIT (PVpit) were automatically calculated. dPSI was defined as the difference between PVpsi and LPpsi. A significant correlation was observed between PAPSI and fibrosis scores. When patients were stratified according to their LPpsi, a significant difference was achieved only between patients with fibrosis score 0–1 vs. 2–3 and 2 vs. 4. Statistically significant differences between all fibrosis scores, except 0 vs. 1 and 3 vs. 4 were observed when dPSI was used to stratify patients. Overall diagnostic accuracy of LPpsi and dPSI measurement for severe fibrosis by area under the receiving operator characteristic curve analysis was, respectively, 0.87 and 0.88.We suggest that liver CEUS perfusion could have the potential to be used as a complementary tool for the evaluation of liver fibrosis. However, further large-scale studies are required to accurately assess its accuracy in the evaluation of liver fibrosis

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

MR breast imaging: A comparative analysis of conventional and parallel imaging acquisition [RM delle mammelle: Confronto tra tecnica convenzionale ed imaging parallelo]

Purpose. The objective of this study was to compare conventional breast magnetic resonance imaging (MRI) with breast MRI acquired with the sensitivity-encoding (SENSE) technique on a 1.5-T MRI scanner in the same patient, on the basis of image quality and kinetics analysis. Materials and methods. Thirty-one patients with suspicious mammography and US findings were included in the study. Conventional breast MRI consisted of the following sequences: T1 (matrix, 288x512); T2 (matrix 225x512); short tau inversion recovery (STIR) (matrix 320x224) and dynamic T1 [2D fast-field echo (FFE)] (matrix 256x512; temporal resolution =80 s). The SENSE technique included the following sequences: T1 (matrix 512x512); T2 (matrix 512x512); short-tau inversion recovery (STIR) (matrix 320x224); dynamic T1 (3D FFE) (matrix 512x512, with a temporal resolution ≤70 s). Image quality was graded on a four-point scale, and the mean scores given to each sequence were compared between the two protocols. The relative enhancement rates and the qualitative features of the signal intensity (SI)/time curves were also compared between the two protocols. Results. The readers found 64 contrast-enhanced lesions in 31 patients. Nineteen patients had a total of 27 malignant lesions. In the remaining 12 patients, 37 benign lesions were found. No significant differences between the two protocols were observed with regard to the mean relative enhancement rates and the qualitative features of the SI/time curves. In detail, the mean image quality scores were higher for SENSE imaging (p<0.05). The mean image quality score for the T1 and T2 morphological sequences were comparable. In contrast, the quality scores for the STIR images differed significantly between the two protocols (p<0.001), and a significant difference was also observed when comparing the T1 postcontrast images (p<0.001). Conclusions. Our data suggest that the SENSE imaging protocol applied in our study is superior to conventional imaging with regard to image quality, especially for T1 postcontrast and STIR images. SENSE imaging protocols may provide an alternative to conventional sequences for contrast-enhanced MRI of the breast using 1.5-T MR scanners. © 2008 Springer-Verlag

FEM analysis of RF breast ablation: Multiprobe versus cool-tip electrode

Background: Radio-frequency ablation (RFA) has recently received much attention as an effective minimally invasive strategy for the local treatment of tumors. The purpose of this study was to evaluate the efficacy of single-needle cool-tip RF breast ablation in terms of temperature distribution and duration of the procedure as compared to multiprobe RF breast ablation. Materials and Methods: Two different commercially available radiofrequency ablation needle electrodes were compared. Finite-element method (FEM) models were developed to simulate the thermoablation procedures. A series of ex vivo radiofrequency thermal lesions were induced to check the response of the FEM calculations. Results: Data obtained from FEM models and from ex vivo procedures showed that cool-tip RF breast ablation assures better performances than multiprobe RF breast ablation in terms of temperature distribution and duration of the procedure. Histopathological analysis of the cool-tip RF thermoablated specimens showed successful induction of coagulation necrosis in the thermoablated specimens. Conclusion: Data obtained from FEM models and from ex vivo procedures suggest that the proposed cool-tip RF breast ablation may kill more tumor cells in vivo with a single application than the multiprobe RF breast ablation

Differences between Proximal versus Distal Intraorbital Optic Nerve Diffusion Tensor Magnetic Resonance Imaging Properties in Glaucoma Patients

Purpose. To analyze in vivo the diffusion tensor magnetic resonance imaging (DT-MRI) properties of the intraorbital optic nerve at two different levels: Proximal to the optic nerve head (ONH) and distal to the ONH at the level of the orbital apex in glaucoma patients. Methods. Twenty-four patients with primary open-angle glaucoma were examined. The categorization into early and severe glaucoma was performed by Hodapp's classification. Fifteen healthy individuals served as controls. DT-MRI was performed with a 3T-MR unit. Results. At early stage mean diffusivity (MD) values were higher at the proximal site with respect to the distal site. On the contrary, a decrease in fractional anisotropy (FA) was observed only relative to patient stage, independent of optic nerve site. Moreover, at early disease stage an increase in overall diffusivities, was evident at the proximal site, whereas at the distal site a decrease of the largest diffusivity and an increase in both the intermediate and smallest diffusivities were observed. FA and MD measured at the proximal site, had, respectively, the highest sensitivity and specificity in discriminating between healthy and glaucomatous eyes. Conclusions. Our study represents the first attempt to evaluate in vivo fiber integrity changes along the optic nerve with DT-MRI. Optic nerve degeneration appears to be a process that affects differently the proximal and the distal segments of the optic nerve. The complementary high sensitivity of FA with the high specificity of MD at the proximal site may provide reliable indexes for the identification of glaucomatous patients at early stages

Capturing the systemic immune signature of a norovirus infection: an n-of-1 case study within a clinical trial.

BACKGROUND: The infection of a participant with norovirus during the adaptive study of interleukin-2 dose on regulatory T cells in type 1 diabetes (DILT1D) allowed a detailed insight into the cellular and cytokine immune responses to this prevalent gastrointestinal pathogen. METHODS: Serial blood, serum and peripheral blood mononuclear cell (PBMC) samples were collected pre-, and post-development of the infection. To differentiate between the immune response to norovirus and to control for the administration of a single dose of aldesleukin (recombinant interleukin-2, rIL-2) alone, samples from five non-infected participants administered similar doses were analysed in parallel. RESULTS: Norovirus infection was self-limited and resolved within 24 hours, with the subsequent development of anti-norovirus antibodies. Serum pro- and anti-inflammatory cytokine levels, including IL-10, peaked during the symptomatic period of infection, coincident with increased frequencies of monocytes and neutrophils. At the same time, the frequency of regulatory CD4 + T cell (Treg), effector T cell (Teff) CD4 + and CD8 + subsets were dynamically reduced, rebounding to baseline levels or above at the next sampling point 24 hours later.  NK cells and NKT cells transiently increased CD69 expression and classical monocytes expressed increased levels of CD40, HLA-DR and SIGLEC-1, biomarkers of an interferon response. We also observed activation and mobilisation of Teffs, where increased frequencies of CD69 + and Ki-67 + effector memory Teffs were followed by the emergence of memory CD8 + Teff expressing the mucosal tissue homing markers CD103 and β7 integrin. Treg responses were coincident with the innate cell, Teff and cytokine response. Key Treg molecules FOXP3, CTLA-4, and CD25 were upregulated following infection, alongside an increase in frequency of Tregs with the capacity to home to tissues. CONCLUSIONS: The results illustrate the innate, adaptive and counter-regulatory immune responses to norovirus infection. Low-dose IL-2 administration induces many of the Treg responses observed during infection

Using magnetic resonance imaging to assess visual deficits : a review

PURPOSE: Over the last two decades, magnetic resonance imaging (MRI) has been widely used in neuroscience research to assess both structure and function in the brain in health and disease. With regard to vision research, prior to the advent of MRI, researchers relied on animal physiology and human post-mortem work to assess the impact of eye disease on visual cortex and connecting structures. Using MRI, researchers can non-invasively examine the effects of eye disease on the whole visual pathway, including the lateral geniculate nucleus, striate and extrastriate cortex. This review aims to summarise research using MRI to investigate structural, chemical and functional effects of eye diseases, including: macular degeneration, retinitis pigmentosa, glaucoma, albinism, and amblyopia. RECENT FINDINGS: Structural MRI has demonstrated significant abnormalities within both grey and white matter densities across both visual and non-visual areas. Functional MRI studies have also provided extensive evidence of functional changes throughout the whole of the visual pathway following visual loss, particularly in amblyopia. MR spectroscopy techniques have also revealed several abnormalities in metabolite concentrations in both glaucoma and age-related macular degeneration. GABA-edited MR spectroscopy on the other hand has identified possible evidence of plasticity within visual cortex. SUMMARY: Collectively, using MRI to investigate the effects on the visual pathway following disease and dysfunction has revealed a rich pattern of results allowing for better characterisation of disease. In the future MRI will likely play an important role in assessing the impact of eye disease on the visual pathway and how it progresses over time