The study included 182 subjects in the analysis. The mean age was 57.7 ± 15.3 years. Of the subjects, 71 (39.0%) met the OAB criteria.
1. Relationship between subjective symptoms and CT findings
1.1. Relationship between OABSS and CT findings
On the abdominal CT scans, the VFA, VFV, and VFV/TAV values were all significantly higher in the OAB group than in the non-OAB group (p < 0.001 for all values). The PMA and PMV values were significantly lower in the OAB group (PMA, p = 0.030; PMV, p = 0.004).
Of these parameters, the VFV/TAV value correlated the most with the total OABSS (r = 0.394, p < 0.001). When a receiver operating characteristic curve was drawn for the VFV/TAV value and the presence/absence of OAB, the area under the curve was 0.742 (p < 0.01). When the cutoff value was set to 0.381, the sensitivity was 0.563 and the specificity was 0.811.
1.2. Relationship between CLSS and CT findings
The VFA, VFV, and VFV/TAV values all had a significant positive correlation with the Q3 (urgency) score. Of them, the VFV/TAV value correlated the most (r = 0.457, p < 0.001). In addition, a positive correlation was observed between the VFV/TAV value and the Q7 (straining) score (r = 0.272, p < 0.001).
Both PMA and PMV values had a significant negative correlation with the Q3 (urgency) score. The PMV value had a stronger negative correlation (r = -0.208, p = 0.005). In addition, there were significant negative correlations of both PMA and PMV values with the Q5 (stress urinary incontinence) score (PMA: r = -0.148, p = 0.046; PMV: r = -0.163, p = 0.028).
2. Relationship between findings of objective symptoms and CT findings
In particular, the maximum flow rate negatively correlated with the VFV/TAV value and positively correlated with the PMV value (VFV/TAV: r = -0.289, p < 0.001; PMV: r = 0.304, p < 0.001).
3. Multivariate analysis
A multivariate analysis of VFV/TAV and PMV values and factors that cause OAB and weak urine flow, such as age, sex, and hypertension, showed that a high VFV/TAV value and age were independent risk factors for OAB, like in the univariate analysis (odds ratio: 2.34, 95% confidence interval: 1.05–5.20, p = 0.038). In addition, a low PMV value was shown to be a risk factor for weak urine flow in the multivariate analysis (odds ratio: 2.09, 95% confidence interval: 1.06–4.12, p = 0.033).