Role of multiparametric magnetic resonance imaging in the diagnosis and staging of urinary bladder cancer

Abstract

Objectives: To assess the role of multiparametric magnetic resonance imaging (mp-MRI) in the diagnosis and staging of urinary bladder cancer (BC).

Materials and methods: Fifty patients diagnosed with bladder masses underwent mp-MRI study. The results of 3 image sets were analyzed and compared with the histopathological results as a reference standard: T2-weighted image (T2WI) plus dynamic contrast-enhanced (DCE), T2WI plus diffusion-weighted images (DWI), and mp-MRI, including T2WI plus DWI and DCE. The diagnostic accuracy of mp-MRI was evaluated using receiver operating characteristic curve analysis.

Results: The accuracy of T2WI plus DCE for detecting muscle invasion of BC was 79.5% with a fair agreement with histopathological examination (κ = 0.59); this percentage increased up to 88.6% using T2WI plus DWI, with good agreement with histopathological examination (κ = 0.74), whereas mp-MRI had the highest overall accuracy (95.4%) and excellent agreement with histopathological data (κ = 0.83). Multiparametric MRI can differentiate between low- and high-grade bladder tumors with a high sensitivity and specificity of 93.3% and 98.3%, respectively.

Conclusions: Multiparametric MRI is an acceptable method for the preoperative detection and accurate staging of BC, with reasonable accuracy in differentiating between low- and high-grade BC.

Keywords: Apparent diffusion coefficient; Bladder cancer; Diffusion-weighted imaging; Multiparametric magnetic resonance imaging; Transurethral resection of bladder tumor.

Figure 1

ROC, sensitivity, and specificity of the ADC value in detecting muscle invasion in bladder cancer. ADC = apparent diffusion coefficient; ROC = receiver operating characteristic curve.

Figure 2

Box plots comparing measured ADC values and their corresponding pathological grades. ADC = apparent diffusion coefficient.

Figure 3

(A) Axial CT of the pelvis reveals a large bladder mass (red arrow). (B) Axial T2W MRI scan of the pelvis reveals a fungating intravesical mass with evidence of muscle layer and perivesical fat invasion (yellow arrows). (C) Axial diffusion-weighted image (b = 1000 s/mm²). (D) ADC map of the pelvis reveals a bladder mass infiltrating the anterior wall and perivesical fat. ADC value = 1 × 10³ mm²/s. (E) Axial DCE. (F) Time-intensity curve showing an enhancing infiltrating bladder mass and evidence of wall infiltration (green arrow) and Type III curve “washout.” ADC = apparent diffusion coefficient; CT = computed tomography; DCE = dynamic contrast enhanced; MRI = magnetic resonance imaging; T2W = T2-weighted. b value measures the degree of diffusion weighting applied, thereby indicating the amplitude (G), time of applied gradients (δ) and duration between the paired gradients (△) and is calculated as: b = γ² G² δ² (△−δ/3).

Figure 4

(A) Axial T2W MRI. (B) Coronal T2W. (C) Sagittal T2W MRI scans of the pelvis show diffuse wall thickening, a sessile mass lesion in the left lateral wall, and evidence of perivesical fat infiltration (red arrows). (D) Axial diffusion-weighted image (b = 1000 s/mm²) of the pelvis reveals bladder mass showing no restricted diffusion “facilitated” (yellow arrows). ADC value = 2.4 × 10³ mm²/s. (E) Time-intensity curve showing a Type I curve “rising.” (F) Hematoxylin-eosin‐stained slide reveals follicular cystitis. ADC = apparent diffusion coefficient; MRI = magnetic resonance imaging; T2W = T2-weighted. b value measures the degree of diffusion weighting applied, thereby indicating the amplitude (G), time of applied gradients (δ) and duration between the paired gradients (△) and is calculated as: b = γ² G² δ² (△−δ/3).

Figure 5

(A) Axial CT image of the pelvis shows a polypoidal mass lesion in the posterior wall. (B) Axial T2WI MRI of the pelvis reveals a polypoidal mass lesion with intact hypointense muscle layer (red arrow). (C) Axial diffusion-weighted image (b = 1000 s/mm²). (D) ADC map of the pelvis reveals a bladder mass with an intact muscle layer and positive inchworm sign (yellow arrows). ADC value = 1.7 × 10³ mm²/s. (E) Sagittal DCE. (F) Time-intensity curve; shows early enhancing bladder mass (green arrow), no early bladder wall enhancement, and Type II curve “plateau.” ADC = apparent diffusion coefficient; CT = computed tomography; DCE = dynamic contrast enhanced; MRI = magnetic resonance imaging; T2WI = T2-weighted image. b value measures the degree of diffusion weighting applied, thereby indicating the amplitude (G), time of applied gradients (δ) and duration between the paired gradients (△) and is calculated as: b = γ² G² δ² (△−δ/3).