Figure 1.

Selection of ultrasound features using the least absolute shrinkage and selection operator (LASSO) logistic regression model in the training dataset. (A) The 12 ultrasound features are profiled by the LASSO coefficient. A coefficient profile plot against the log (λ) sequence was produced; (B) the area under the receiver-operating characteristic curve was plotted versus log (λ). The minimum criteria, together with 1 standard error of the minimum criteria (1 – SE criteria), was used to draw the dotted vertical lines at the optimal values. A λ value of 0.096, with log (λ) –3.385 was chosen (1 – SE criteria) according to 10-fold cross-validation, where optimal λ resulted in 3 nonzero coefficients.