Diagnostic performance of multiparametric MRI based Vesical Imaging-Reporting and Data System (VI-RADS) scoring in discriminating between non-muscle invasive and muscle invasive bladder cancer

Abstract

Purpose: The purpose of the present study was to assess the diagnostic accuracy of the Vesical Imaging-Reporting and Data System (VI-RADS) scoring system in predicting muscle infiltration of bladder cancer (BC) on a pre-operative multiparametric magnetic resonance imaging (mpMRI).

Methods: The prospective study enrolled patients with bladder lesions detected on a preliminary ultrasonography or cystoscopy. The patients underwent mpMRI on a 3T MRI scanner followed by surgery within 2 weeks. The tumours were assigned a VI-RADS score by 2 experienced abdominal radiologists. The VI-RADS score was compared with postoperative histopathological findings to confirm detrusor muscle infiltration. The diagnostic performance of VI-RADS for predicting muscle invasion was assessed by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy.

Results: A total of 60 patients were included in the study with a male: female ratio of 4.4 : 1. Transurethral resection of bladder tumour (TURBT) was performed in 47 (78.4%) and radical cystectomy in 13 (21.6%) patients. 19 (31.7%) had non-muscle invasive invasive BC (NMIBCa) and 41 (68.3%) had muscle invasive BC (MIBCa) on histopathology. There was a significant association between VI-RADS score and its components with muscle invasion (p < 0.05). A VI-RADS score of ≥ 3 had a sensitivity of 97.56% (95% CI: 0.87-0.99%), specificity of 73.68% (95% CI: 0.49-0.91), positive predictive value of 88.9% (95% CI: 0.79-0.94), negative predictive value of 93.33% (95% CI: 0.66-0.99), and diagnostic accuracy of 90% (95% CI: 0.80-0.96) for prediction of muscle invasion.

Conclusion: VI-RADS scoring system pre-operatively predicts the likelihood of muscle invasion in BC with a satisfactory diagnostic performance, and it should be incorporated in the diagnostic work-up of BC patients.

Keywords: Vesical Imaging-Reporting and Data System (VI-RADS); bladder cancer; multiparametric magnetic resonance imaging (mpMRI); muscle invasion; prediction.

Figure 1

A 54-year-old man with positive cystoscopy for bladder mass. T2-weighted MR image (A) shows a polyploidal mass (arrow) less than 1 cm in size at right lateral bladder wall with intermediate signal intensity that does not extend through muscularis propria. T2-weighted imaging evaluation of mass was SC 1. DWI image (B) and ADC map (C) shows lesion with restricted diffusion that does not extend through muscularis propria. DWI evaluation of mass was DWI 1. Dynamic contrast-enhanced (DCE) MR image (D) shows early enhancement of lesion not extending through muscularis propria. DCE-MRI evaluation of mass was DCE 1. Overall, the VI-RADS score was 1. Histology showed non-muscle invasive lesion

Figure 2

A 62-year-old man with haematuria and positive cystoscopy for bladder mass. Axial T2-weighted MR image (A) shows papillary mass on left posterolateral wall with stalk greater than 1 cm with intermediate signal intensity that does not extend through muscularis propria (SC 2). DWI (B) and ADC map (C) shows lesion with restricted diffusion, not extending through muscularis propria (DWI 2). Dynamic contrast-enhanced (DCE) MR image (D) shows early enhancement of lesion, not extending through muscularis propria (CE 2). Overall, the VI-RADS score was 2. Histology showed non-muscle invasive lesion

Figure 3

A 58-year-old female patient with an exophytic tumour located at the posterior wall of the bladder. Axial T2-weighted image (A) shows intermediate signal tumour with no clear interruption of low-signal intensity muscularis propria. DWI (B) and ADC map (C) shows no clear interruption of muscularis propria. DCE image (D) shows no early enhancement of muscularis propria with interrupted enhanced linear submucosa. A VI-RADS score of 3 was obtained. Histology showed non-muscle invasive lesion

Figure 4

A 60-year-old male patient with history of haematuria. T2-weighted axial image (A) shows posterior wall papillary mass lesion disrupting the underneath hypo-intense detrusor lining, with no extension to perivesical fat (SC 4). Axial DWI (B) and ADC (C) shows diffusion restricting tumour with disruption of low signal intensity muscularis propria, with no extension to perivesical fat. DCE-MRI shows early enhancement of the tumour extending into muscle layer denoting muscle invasion (CE 4). A VI-RADS score of 4 was assigned. Histology con- firmed muscle invasion

Figure 5

A 77-year-old male patient with positive cystoscopy for bladder mass. Axial T2-weighted MR image (A) shows polyploidal mass arising from antero-lateral bladder wall with intermediate signal intensity that extends through muscularis propria, invading perivesical fat tissue (SC 5). DWI (C) and ADC map (D) shows lesion with restricted diffusion extending through muscularis propria invading perivesical fat tissue (DW 5). Dynamic contrast-enhanced (DCE) MR image (D) shows early and heterogeneous enhancement of lesion extending through muscularis propria invading perivesical fat tissue (CE 5). Overall, the VI-RADS score was 5. Histology confirmed muscle invasion