Assessment of liver viscoelasticity by using shear waves induced by ultrasound radiation force.

PURPOSE: To investigate the value of viscosity measured with ultrasonographic (US) elastography in liver fibrosis staging and to determine whether the use of a viscoelastic model to estimate liver elasticity can improve its accuracy in fibrosis staging. MATERIALS AND METHODS: The study, which was performed from February 2010 to March 2011, was compliant with HIPAA and approved by the institutional review board. Written informed consent was obtained from each subject. Ten healthy volunteers (eight women and two men aged 27-55 years) and 35 patients with liver disease (17 women and 18 men aged 19-74 years) were studied by using US elasticity measurements of the liver (within 6 months of liver biopsy). US data were analyzed with the shear wave dispersion ultrasound vibrometry (SDUV) method, in which elasticity and viscosity are measured by evaluating dispersion of shear wave propagation speed, as well as with the time-to-peak (TTP) method, where tissue viscosity was neglected and only elasticity was estimated from the effective shear wave speed. The hepatic fibrosis stage was assessed histologically by using the METAVIR scoring system. The correlation of elasticity and viscosity was assessed with the Pearson correlation coefficient. The performances of SDUV and TTP were evaluated with receiver operating characteristic (ROC) curve analysis. RESULTS: The authors found significant correlations between elasticity and viscosity measured with SDUV (r = 0.80) and elasticity measured with SDUV and TTP (r = 0.94). The area under the ROC curve for differentiating between grade F0-F1 fibrosis and grade F2-F4 fibrosis was 0.98 for elasticity measured with SDUV, 0.86 for viscosity measured with SDUV, and 0.95 for elasticity measured with TTP. CONCLUSION: The results suggest that elasticity and viscosity measured between 95 Hz and 380 Hz by using SDUV are correlated and that elasticity measurements from SDUV and TTP showed substantially similar performance in liver fibrosis staging, although elasticity calculated from SDUV provided a better area under the ROC curve.

Is antibiotic prophylaxis necessary for midurethral sling procedures? A series of 174 cases without preoperative antibiotics.

INTRODUCTION AND HYPOTHESIS: Despite the lack of evidence, antibiotic prophylaxis has been recommended for midurethral sling procedures. The goal of this study was to evaluate the rate of infectious complications in women undergoing midurethral sling procedures without antibiotic prophylaxis. METHODS: We reviewed the baseline characteristics and postoperative infectious complications of 174 consecutive women who underwent midurethral sling procedures without prophylactic antibiotics from April 2005 to January 2010. Patients undergoing concomitant vaginal surgery were excluded. RESULTS: The average age, parity, and body mass index of were 51.3 ± 12.6 years, 2.4 ± 1.3, and 30.1 ± 7.4 kg/m(2), respectively. There were no wound infections, 2 (1.4%) vaginal mesh exposures and 12 (8%) cases of bacteriuria. CONCLUSIONS: The risk of infections is low when a midurethral sling is performed without antibiotic prophylaxis. Antibiotic prophylaxis does not appear to offer any benefit in midurethral sling procedures.

Double-blinded randomized trial of preoperative antibiotics in midurethral sling procedures and review of the literature.

INTRODUCTION AND HYPOTHESIS: The objective of this study was to determine if prophylactic antibiotic use before midurethral sling procedures reduces infectious complications. METHODS: In this double-blinded randomized trial, we compared infectious complications between women who received cefazolin and placebo before midurethral sling procedures. RESULTS: The study was halted due to low rate of infectious outcomes seen at the first scheduled interim analysis. We enrolled 29 women in the cefazolin group and 30 in the placebo group. Total follow-up was 6 months (3-24 months). The groups were similar at the baseline. There was no statistically significant difference between the cefazolin and placebo groups, respectively, with respect to wound infections [1 (3.3%) and 0 (0%)], mesh exposure [0 (0%) and 1 (3.5%)], and bacteriuria [3 (10%) and 1 (3.5%)]. CONCLUSION: Because infection rates are low in both cefazolin and placebo groups, omitting preoperative antibiotics for midurethral slings may be justified.

Definitions for a common standard for 2D speckle tracking echocardiography: consensus document of the EACVI/ASE/Industry Task Force to standardize deformation imaging.

Recognizing the critical need for standardization in strain imaging, in 2010, the European Association of Echocardiography (now the European Association of Cardiovascular Imaging, EACVI) and the American Society of Echocardiography (ASE) invited technical representatives from all interested vendors to participate in a concerted effort to reduce intervendor variability of strain measurement. As an initial product of the work of the EACVI/ASE/Industry initiative to standardize deformation imaging, we prepared this technical document which is intended to provide definitions, names, abbreviations, formulas, and procedures for calculation of physical quantities derived from speckle tracking echocardiography and thus create a common standard.

Definitions for a common standard for 2D speckle tracking echocardiography: consensus document of the EACVI/ASE/Industry Task Force to standardize deformation imaging.

Recognizing the critical need for standardization in strain imaging, in 2010, the European Association of Echocardiography (now the European Association of Cardiovascular Imaging, EACVI) and the American Society of Echocardiography (ASE) invited technical representatives from all interested vendors to participate in a concerted effort to reduce intervendor variability of strain measurement. As an initial product of the work of the EACVI/ASE/Industry initiative to standardize deformation imaging, we prepared this technical document which is intended to provide definitions, names, abbreviations, formulas, and procedures for calculation of physical quantities derived from speckle tracking echocardiography and thus create a common standard.