Prostate Imaging Reporting and Data System (PI-RADS) Score V2.1 has improved the detection of clinically significant prostate cancer (csPCa). A majority of prostate cancer (PCa) arises from the Peripheral Zone (70-80%). 20- 25% of PCa arises in the TZ while 1-8% of PCa is identified in the CZ. Despite PI-RADS v2.1 consideration of zonal imaging differences, competing disease, such as BPH, mimic suspicious lesions, and pose diagnostic challenges. PSA density (PSAD), a surrogate for discerning BPH and PCa, has yet to be included in the evaluation of suspicious PI-RADS lesions.

Single center retrospective review of patients (2016-2023) harboring PI-RADS 3-5 lesions who subsequently underwent prostate biopsy. CsPCa defined as Grade Group (GG) ≥ 2. Imaging and pathology reviewed by radiologist and pathologist respectively. PSAD and ADC values were stratified as ≥ 0.15 ng/mL2 vs. < 0.15 ng/mL, and ≥700 vs <700mm2/s x10-6 respectively.

PZ has a 3.2x greater chance of harboring GG2-GG5 as compared to the TZ for all PI-RADS 3-5 lesions. A PSAD cutoff of ≥.15 ng/mL 2 has a 4.76x increased risk of GG2-GG5 for all PI-RADS 3-5 lesions as compared to a PSAD.

The PZ and a PSAD cutoff ≥0.15 were strongly associated with a higher detection of csPCa across all PI-RADS scores. In TZ lesions with low PSAD patients, csPCA rate ranged from 6.7%-52.9% as compared to high PSAD and PZ lesions (35.7-95.5%). In cases of low probability (<10%), omission of biopsy can be considered. The addition of PSAD and zonal distribution of MRI visible lesions may serve as a useful adjunct when discussing risk stratification and biopsy needs