Objective: To determine the detection of clinically significant prostate cancer (csPCa) index lesion using high resolution transrectal micro-ultrasound (MicroUS) applying PRI-MUS (Prostate Risk Identification using Micro Ultrasound) score v1.0. Methods: Men who underwent radical prostatectomy following biopsy and MicroUS assessment were included. MicroUS dynamic cine loops of these patients were retrospectively reviewed by an experienced radiologist. The radiologist was aware that patients had undergone radical prostatectomy but was blinded to pathological data. Suspicious sites were assigned a PRI-MUS score. Radical prostatectomy specimens were examined with the quarter mount technique. Detection rate of csPCa index lesion [Grade Group (GG) ≥2] by MicroUS was assessed at a patient level. Results: Twenty-five participants were included in the analysis. The median age was 65.5 years (range 56-74). Median PSA was 6.45 ng/dL (range 2-31.72). Two of 25 patients did not have csPCa (GG1 disease) on radical prostatectomy. MicroUS visualized 20/23 (87%) of the csPCa index lesions [median length 9 mm (range 1.5- 28.5)]. All identified lesions were categorized PRIMUS score 4 or 5. The 3 missed index lesions were in the transition zone [median length 10.5 mm (range 4.5-22.5)]. MicroUS missed 11 non index csPCa in 9 participants [median length 1.5 mm (range 1.5-10.5)]. Of these, 8 were GG2, 2 GG3 and 1 GG5. MicroUS identified the csPCa index lesion in all 9 of these men. Conclusion: MicroUS showed the high sensitivity (87%) in detecting index lesions in the prostate gland and identified 100% of index lesions in the peripheral zone.