Introduction: The purpose of this study was to compare the diagnostic accuracy between multiparametric magnetic resonance imaging (mp-MRI) and biparametric magnetic resonance imaging (bp-MRI) in muscle-invasive bladder cancer (MIBC). Methods: The acquired images are divided into two sets. Set 1 (bp-MRI) included the axial, sagittal, coronal T2WI, and axial DWI/ADC images. Set 2 (mp-MRI) included Set 1 images in addition to DCE images. mp-MRI was evaluated according to VI-RADS score guideline, and bp-MRI was evaluated according to two types of MRI score criteria. bp-MRI (criteria 1, C1): VI-RADS score was determined 2 when SC 3 and DW 2 (SC 3+DW 2). bp-MRI (criteria 2, C2): VI-RADS score was determined 3 when SC 3 and DW 2. VI-RADS score =3 and 4 were respectively used as the cut-off value for predicting MIBC. The sensitivity, specificity, false positive rate (FPR), and false negative rate (FNR) of mp-MRI, bp-MRI (C1), and bp-MRI (C2) were calculated, as well as ROC and areas under the curves (AUCs). Results: When the cut-off value was =3, the sensitivity, specificity, FPR and FNR of bp-MRI (C1) were 0.91, 0.91, 0.19 and 0.04, respectively. The sensitivity, specificity, FPR and FNR of bp-MRI (C2) were 0.91, 0.83, 0.33 and 0.04, respectively. The sensitivity, specificity, FPR and FNR of mp-MRI were 0.91, 0.89, 0.23 and 0.04, respectively. When the cut-off value was =4, both bp-MRI (C1) and bp-MRI (C2) results were the same. The sensitivity, specificity, FPR and FNR were 0.75, 0.99, 0.04 and 0.09, respectively. Using mp-MRI, the sensitivity, specificity, FPR and FNR were 0.84, 0.99, 0.04 and 0.06, respectively. The AUCs for bp-MRI (C1), bp-MRI (C2) and mp-MRI were 0.953, 0.942 and 0.955, respectively. No significant difference of AUC in predicting MIBC was observed between bp-MRI (C1) and mp-MRI (P=0.512). bp-MRI (C1) and mp-MRI both had significant higher diagnostic accuracy than bp-MRI (C2) in predicting MIBC (P=0.029 and 0.037, respectively). Conclusions: bp-MRI (C1) and mp-MRI demonstrated comparable diagnostic accuracy in predicting MIBC. bp-MRI (C1) had better diagnostic accuracy than bp-MRI (C2) in predicting MIBC. Compared with mp-MRI, patients may benefit from RC or other aggressive treatments when bp-MRI (C1) prompted MIBC. SOURCE OF Funding: None
