MRI-based transperineal biopsy performed at high-volume tertiary care centres with a significant experience of prostate mpMRI and image-guided targeted biopsies yielded high detection rates of Gleason score 7-10 cancer. Prostate biopsies may not be needed for men with low PSAD and an unsuspicious MRI. In patients with high probability lesions, combined targeted and systematic biopsies are recommended.

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In patients with high probability mpMRI lesions, the highest detection rates of Gleason score 7-10 cancer still required combined targeted and systematic MRI/US image-fusion; however, systematic biopsy alone may be sufficient in patients with equivocal lesions. Repeated prostate biopsies may not be needed at all for patients with a low PSA density and a negative mpMRI read by experienced radiologists.

ObjectivesTo assess cancer detection rates of different target-dependent transperineal magnetic resonance (MR)/ultrasonography (US) fusion-guided biopsy templates with reduced number of systematic cores. Patients and MethodsSingle-centre outcome of transperineal MR/US fusionguided biopsies of 487 men with a single target MR imaging (MRI) lesion, prospectively collected between 2012 and 2016. All men underwent transperineal targeted biopsy (TB) with two cores, followed by 18-24 systematic sector biopsies (SB) using the Ginsburg protocol. Gleason score ≥7 prostate cancer detection rates for two-core TB, fourcore extended TB (eTB), 10-to 20-core saturation TB (sTB) including cores from sectors adjacent to the target, and 14 core ipsilateral TB (iTB) were compared to combined TB+SB. ResultsCancer was detected in 345 men and Gleason score 7-10 cancer in 211 men. TB alone detected 67%, eTB 76%, sTB 91% and iTB 91% of these Gleason score 7-10 cancers. In the subgroup of 33 men (7% of cohort) with an anterior >0.5 mL highly suspicious MRI lesion and a prostate volume ≤45 mL, four-core eTB detected 31 of 32 cancers (97%) and all 26 Gleason score 7-10 cancers.Conclusion sTB detected Gleason score 7-10 cancer in 25% more of the men than a two-core TB approach, and in almost as many men (91%) as the 20-26-core combined TB+SB, while needing only 10-20 cores. A four-core extended TB may suffice for large, highly suspicious anterior lesions in small or slightly enlarged prostates.

In a repeat biopsy setting, a PSAD of ≤0.2 ng/mL/mL is associated with low detection of Gleason score ≥7 prostate cancer, not only in men with negative mpMRI, but also in men with equivocal imaging. Surveillance, rather than repeat biopsy, may be appropriate for these men. Conversely, biopsies are indicated in men with a high PSAD, even if an mpMRI shows no suspicious lesion, and in men with an mpMRI suspicious for cancer, even if the PSAD is low.

MR imaging is useful for the noninvasive work-up of lesions classified as BI-RADS category 4 at mammography or US and can help avoid 92% of unnecessary biopsies. The false-negative rate was 0% for all US findings and for all mammographic findings except pure clustered microcalcifications. Additional invasive cancers were identified in three women with false-positive findings from mammography and US.

Rectal distension has a significant negative effect on the quality of both T2W and DW images. Consideration should therefore be given to bowel preparation prior to prostate mpMRI to optimise image quality.

ObjectivesTo investigate the value of second-opinion evaluation of multiparametric prostate magnetic resonance imaging (MRI) by subspecialised uroradiologists at a tertiary centre for the detection of significant cancer in transperineal fusion prostate biopsy.MethodsEvaluation of prospectively acquired initial and second-opinion radiology reports of 158 patients who underwent MRI at regional hospitals prior to transperineal MR/untrasound fusion biopsy at a tertiary referral centre over a 3-year period. Gleason score (GS) 7-10 cancer, positive predictive value (PPV) and negative (NPV) predictive value (±95 % confidence intervals) were calculated and compared by Fisher’s exact test.ResultsDisagreement between initial and tertiary centre second-opinion reports was observed in 54 % of cases (86/158). MRIs had a higher NPV for GS 7-10 in tertiary centre reads compared to initial reports (0.89 ± 0.08 vs 0.72 ± 0.16; p = 0.04), and a higher PPV in the target area for all cancer (0.61 ± 0.12 vs 0.28 ± 0.10; p = 0.01) and GS 7-10 cancer (0.43 ± 0.12 vs 0.2 3 ± 0.09; p = 0.02). For equivocal suspicion, the PPV for GS 7-10 was 0.12 ± 0.11 for tertiary centre and 0.11 ± 0.09 for initial reads; p = 1.00.ConclusionsSecond readings of prostate MRI by subspecialised uroradiologists at a tertiary centre significantly improved both NPV and PPV. Reporter experience may help to reduce overcalling and avoid overtargeting of lesions.Key Points• Multiparametric MRIs were more often called negative in subspecialist reads (41 % vs 20 %).• Second readings of prostate mpMRIs by subspecialist uroradiologists significantly improved NPV and PPV.• Reporter experience may reduce overcalling and avoid overtargeting of lesions.• Greater education and training of radiologists in prostate MRI interpretation is advised.Electronic supplementary materialThe online version of this article (doi:10.1007/s00330-016-4635-5) contains supplementary material, which is available to authorized users.