STATISTICAL ANALYSIS Data were analyzed using the SPSS 15 software package (SPSS Inc., Chicago, Illinois, USA). Continuous variables were summarized as means ± SD, or range, when appropriate. Categorical variables were summarized as frequency and percentage. For comparison of qualitative variables, a chi-squared test was calculated. For comparison of quantitative variables, Students t test was used. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy for each arm was investigated. Differences were considered significant at a P value of <0.05 (two-sided).