Hepatosplenic volumetric assessment at MDCT for staging liver fibrosis.

PURPOSE: To investigate hepatosplenic volumetry at MDCT for non-invasive prediction of hepatic fibrosis. METHODS: Hepatosplenic volume analysis in 624 patients (mean age, 48.8 years; 311 M/313 F) at MDCT was performed using dedicated software and compared against pathological fibrosis stage (F0 = 374; F1 = 48; F2 = 40; F3 = 65; F4 = 97). The liver segmental volume ratio (LSVR) was defined by Couinaud segments I-III over segments IV-VIII. All pre-cirrhotic fibrosis stages (METAVIR F1-F3) were based on liver biopsy within 1 year of MDCT. RESULTS: LSVR and total splenic volumes increased with stage of fibrosis, with mean(±SD) values of: F0: 0.26 ± 0.06 and 215.1 ± 88.5 mm3; F1: 0.25 ± 0.08 and 294.8 ± 153.4 mm3; F2: 0.331 ± 0.12 and 291.6 ± 197.1 mm3; F3: 0.39 ± 0.15 and 509.6 ± 402.6 mm3; F4: 0.56 ± 0.30 and 790.7 ± 450.3 mm3, respectively. Total hepatic volumes showed poor discrimination (F0: 1674 ± 320 mm3; F4: 1631 ± 691 mm3). For discriminating advanced fibrosis (≥F3), the ROC AUC values for LSVR, total liver volume, splenic volume and LSVR/spleen combined were 0.863, 0.506, 0.890 and 0.947, respectively. CONCLUSION: Relative changes in segmental liver volumes and total splenic volume allow for non-invasive staging of hepatic fibrosis, whereas total liver volume is a poor predictor. Unlike liver biopsy or elastography, these CT volumetric biomarkers can be obtained retrospectively on routine scans obtained for other indications. KEY POINTS: • Regional changes in hepatic volume (LSVR) correlate well with degree of fibrosis. • Total liver volume is a very poor predictor of underlying fibrosis. • Total splenic volume is associated with the degree of hepatic fibrosis. • Hepatosplenic volume assessment is comparable to elastography for staging fibrosis. • Unlike elastography, volumetric analysis can be performed retrospectively.

The Liver Segmental Volume Ratio for Noninvasive Detection of Cirrhosis: Comparison With Established Linear and Volumetric Measures.

OBJECTIVE: The aim of this study was to compare the liver segmental volume ratio (LSVR), a novel volumetric computed tomography measurement, with established linear measurements for differentiating normal from cirrhotic livers. METHODS: Hepatic volumes were measured using semiautomated software (Liver Analysis Application, Philips IntelliSpace Portal) on contrast-enhanced abdominal computed tomography scans in 312 adults, including 108 patients with end-stage liver disease (mean age, 55 years; 63 men/45 women) and 204 healthy controls (potential renal donors; mean age, 46 years; 82 men/122 women). The LSVR was defined as the volume ratio of Couinaud segments I to III to segments IV to VIII. Linear measures included the caudate-to-right lobe ratio and maximal splenic dimension. RESULTS: Differences in LSVR between cirrhotics and controls were highly significant (P < 0.0001; mean, 0.55 ± 0.29 versus 0.27 ± 0.07; receiver operating characteristic [ROC] area under the curve [AUC], 0.916). Linear caudate-to-right lobe ratio differences were not statistically significant between the 2 cohorts (P = 0.051; ROC AUC, 0.567). Total liver volume was ineffective for discrimination (ROC AUC, 0.598). An LSVR threshold of 0.35 or greater had a sensitivity and specificity for cirrhosis of 81.5% and 88.7%, respectively. CONCLUSIONS: Regional hepatic volume changes, as reflected by the LSVR, are more effective than standard linear measures or total liver volume for differentiating cirrhotic from normal livers.

Heterogeneous oxidation of nitrite anion by gas-phase ozone in an aqueous droplet levitated by laser tweezers (optical trap): is there any evidence for enhanced surface reaction?

The oxidation of nitrite anion within an aqueous atmospheric droplet may be a sink for HONO in the lower atmosphere. An optical trap with Raman spectroscopy is used to demonstrate that the oxidation of aqueous nitrite anion in levitated, micron sized, aqueous droplets by gas-phase ozone is consistent with bulk aqueous-phase kinetics and diffusion. There is no evidence of an enhanced or retarded reaction at the droplet surface at the concentrations used in the experiment or likely to be found in the atmosphere. The oxidation of nitrite in an aqueous droplet by gas-phase ozone does not cause the droplet to hydrodynamically change in size and demonstrates use of an optical trap as a wall-less reactor to measuring aqueous-phase rate coefficients.

Inflammatory dendritic cells migrate in and out of transplanted chronic mycobacterial granulomas in mice.

An estimated one-third of the world's population is infected with Mycobacterium tuberculosis, although most affected individuals maintain a latent infection. This control is attributed to the formation of granulomas, cell masses largely comprising infected macrophages with T cells aggregated around them. Inflammatory DCs, characterized as CD11c+CD11b+Ly6C+, are also found in granulomas and are an essential component of the acute immune response to mycobacteria. However, their function during chronic infection is less well understood. Here, we report that CD11c+ cells dynamically traffic in and out of both acute and chronic granulomas induced by Mycobacterium bovis strain bacillus Calmette-Guérin (BCG) in mice. By transplanting Mycobacterium-induced granulomas containing fluorescently labeled CD11c+ cells and bacteria into unlabeled mice, we were able to follow CD11c+ cell trafficking and T cell activation. We found that half of the CD11c+ cells in chronic granulomas were exchanged within 1 week. Compared with tissue-resident DC populations, CD11c+ cells migrating out of granuloma-containing tissue had an unexpected systemic dissemination pattern. Despite low antigen availability, systemic CD4+ T cell priming still occurred during chronic infection. These data demonstrate that surveillance of granulomatous tissue by CD11c+ cells is continuous and that these cells are distinct from tissue-resident DC populations and support T cell priming during both stages of Mycobacterium infection. This intense DC surveillance may also be a feature of Mycobacterium tuberculosis infection and other granuloma-associated diseases.