Standardised scoring of a multi-parametric 3-T MRI for a targeted MRI-guided prostate biopsy

The use of multi-parametric MRI and MRI-guided biopsy for the detection of prostate cancer is rapidly increasing. This is a pilot study to evaluate the consensus-based international MRI scoring system as decision criterion for targeted MRI-guided prostate biopsy. After a multi-parametric 3-T MRI (T2-weighted imaging, diffusion-weighted imaging, and dynamic contrast-enhanced MRI) in 23 consecutive patients a total of 47 lesions were scored according to a 5-point scale for each MRI sequence. A total score of a parts per thousand yen10 points was considered to be suspicious for prostate cancer. All 47 lesions were histologically assessed after MRI-guided biopsy. At the cut-off score of 10 points, sensitivity, specificity, negative predictive value and positive predictive value of multi-parametric MRI were 94.1, 43.3, 92.9 and 48.5%, respectively. A standardised scoring of lesions on multi-parametric MRI is feasible. The cut-off value leads to excellent values for sensitivity and negative predictive value. The values for specificity and positive predictive value are modest. Lesions with a total score < 10 points are very unlikely to be malignant.