Statistical methods
Statistical analysis was performed with MATLAB 2015b program (MathWorks Inc., Natick, MA, U.S.A.). Patients with MSFB were divided into two groups based on whether they presented IH on CT images; clinical characteristics and CT findings were compared between groups. Univariate analysis of categorical variables was performed using the χ2 test or Fisher’s exact test, where appropriate. Univariate analysis of continuous variables was performed using the Mann–Whitney U test. Logistic regression analysis was performed to evaluate the associations of multiple different variables with MSFB without IH. For each significant independent variable, the odds ratio (OR) and 95% confidence interval were calculated. A P-value of <.05 was considered to be statistically significant.