Objective
To compare prospectively the diagnostic performance of a biparametric (T2‐weighted imaging [T2WI] and diffusion‐weighted imaging [DWI]) 1.5‐T fast magnetic resonance imaging (fMRI) protocol with the standard 3.0‐T multiparametric MRI (mpMRI) protocol of the European Society of Urological Imaging (ESUR) in men referred for a prostate biopsy.
Patients and Methods
Ninety patients with a prostate cancer (PCa) risk of ≥10% according to the SWOP calculator 4 underwent first fMRI and then the reference mpMRI. Patients with Prostate Imaging Reporting and Data System (PI‐RADS) v.2 lesions ≥3/5 on the mpMRI were scheduled for MRI/ultrasonography (US) fusion‐guided prostate biopsy. Performance of fMRI was assessed using receiver‐operating characteristic curve analysis and mpMRI as reference. Calculation of inter‐technique agreement on PI‐RADS v.2 score by Cohen's κ.
Results
The diagnostic accuracy of fMRI shown by the lesion‐based analysis was excellent: area under the curve (AUC) 0.961 (P < 0.001), sensitivity 95%, specificity 97%, positive predictive value (PPV) 99%, negative predictive value (NPV) 89%. The patient‐based analysis showed an AUC for fMRI of 0.975 (P < 0.001), a sensitivity of 98%, a specificity of 97%, a PPV of 98% and an NPV of 97%. Agreement on the PI‐RADS score between both protocols was found to be good (κ = 0.78 [0.57; 0.99]); fMRI missing PI‐RADS 4 lesions in three patients. Biopsy results showed no cancer in two patients (two cores per nodule) and Gleason 6 cancer in one patient. There was only one false‐positive fMRI, with a PI‐RADS score of 4, whose biopsy was negative.
Conclusion
In the triage of men with a high risk of PCa for prostate biopsy, an f MRI protocol (1.5‐T magnet, T2WI + DWI, <15 min) may safely replace the traditional ESUR 3.0‐T mpMRI protocol, saving time and contrast injection.