Talwalkar, Jayant A.

PurposeTo investigate the influence of portal pressure on the shear stiffness of the liver and spleen in a well‐controlled in vivo porcine model with magnetic resonance elastography (MRE). A significant correlation between portal pressure and tissue stiffness could be used to noninvasively assess increased portal venous pressure (portal hypertension), which is a frequent clinical condition caused by cirrhosis of the liver and is responsible for the development of many lethal complications.Materials and MethodsDuring multiple intraarterial infusions of Dextran‐40 in three adult domestic pigs in vivo, 3D abdominal MRE was performed with left ventricle and portal catheters measuring blood pressure simultaneously. Least‐squares linear regressions were used to analyze the relationship between tissue stiffness and portal pressure.ResultsLiver and spleen stiffness have a dynamic component that increases significantly following an increase in portal or left ventricular pressure. Correlation coefficients with the linear regressions between stiffness and pressure exceeded 0.8 in most cases.ConclusionThe observed stiffness–pressure relationship of the liver and spleen could provide a promising noninvasive method for assessing portal pressure. Using MRE to study the tissue mechanics associated with portal pressure may provide new insights into the natural history and pathophysiology of hepatic diseases and may have significant diagnostic value in the future. J. Magn. Reson. Imaging 2013;38:809–815. © 2013 Wiley Periodicals, Inc.

Summary Background Emerging data suggest that oral antibiotics may have therapeutic effects in primary sclerosing cholangitis ( PSC ), but published studies are limited. Aims To investigate the safety and efficacy of oral vancomycin and metronidazole in patients with PSC . Methods Thirty‐five patients with PSC were randomised in a double‐blind manner into four groups: vancomycin 125 mg or 250 mg four times/day, or metronidazole 250 mg or 500 mg three times/day for 12 weeks. The primary endpoint was decrease in alkaline phosphatase ( ALK ) at 12 weeks. Secondary end points included serum bilirubin and Mayo PSC risk score; pruritus; and adverse effects ( AE s). Nonparametric tests were used for analysis. Results The primary endpoint was reached in the low‐dose (−43% change in ALK , P = 0.03) and high‐dose (−40%, P = 0.02) vancomycin groups, with two patients in the former experiencing ALK normalisation. Bilirubin decreased significantly in the low‐dose metronidazole group (−20%, P = 0.03) and trended towards significance in the low‐dose vancomycin group (−33%, P = 0.06). Mayo PSC risk score decreased significantly in the low‐dose vancomycin (−0.55, P = 0.02) and low‐dose metronidazole group (−0.16, P = 0.03). Pruritus decreased significantly in the high‐dose metronidazole group (−3.4, P = 0.03). AE s led to medication discontinuation in six patients, four of whom were receiving metronidazole. Conclusions Both vancomycin and metronidazole demonstrated efficacy; however, only patients in the vancomycin groups reached the primary endpoint, and with less adverse effects. Larger, longer‐term studies are needed to further examine the safety and efficacy of antibiotics as a potential treatment for patients with primary sclerosing cholangitis ( clinicaltrials.gov NCT01085760 ).

PurposeTo provide a fully automated algorithm for obtaining stiffness measurements from hepatic magnetic resonance elastography (MRE) images that are consistent with measurements performed by expert readers.Materials and MethodsAn initial liver contour was found using an adaptive threshold and expanded using an active contour to select a homogeneous area of the liver. The confidence map generated during the stiffness calculation was used to select a region of reliable wave propagation. The average stiffness within the automatically generated region of interest (ROI) was compared to measurements by two trained readers in a set of 88 clinical test cases ranging from healthy to severely fibrotic.ResultsThe stiffness measurements reported by the readers differed by −6.76% ± 22.8% (95% confidence) and had an intraclass correlation coefficient (ICC) of 0.972 (P < 0.05). The algorithm and the more experienced reader differed by 4.32% ± 14.9 with an ICC of 0.987.ConclusionThe automated algorithm performed reliably, even though MRE acquisitions often have motion artifacts present. The correlation between the automated measurements and those from the trained readers was superior to the correlation between the readers. J. Magn. Reson. Imaging 2013;38:371–379. © 2013 Wiley Periodicals, Inc.