RPS 1107 - Prostate cancer MR imaging: today and tomorrow

Author Block: A. Ng, P. T. G. .; London/UK
Purpose: Multiparametric MRI (mpMRI) ± prostate biopsy is internationally recommended for diagnosing clinically significant prostate cancer (csPCa). However, resource limitations limit global adoption. The PRIME trial (NCT04571840) aimed to evaluate whether biparametric MRI (bpMRI) without intravenous contrast, was non-inferior to mpMRI in detecting csPCa.
Methods or Background: In a prospective, multicentre, within-patient, non-inferiority trial, biopsy naïve men with suspected PCa underwent mpMRI. Radiologists first reported bpMRI (T2-weighted and diffusion weighted imaging) blinded to the dynamic contrast enhanced (DCE) sequences. After unblinding to DCE, radiologists reported the full mpMRI.

Men with bpMRI or mpMRI suggesting PCa underwent MRI-targeted ± systematic biopsy. Men whose MRI were not suggestive of PCa, but PSA density ≥0.15 ng/mL/mL received systematic biopsy. The primary outcome was the proportion of men diagnosed with csPCa (Gleason grade group (GGG) ≥2). Secondary outcomes included the proportion of men diagnosed with clinically insignificant PCa (ciPCa) (GGG 1), and csPCa (GGG ≥3).
Results or Findings: 490 patients included in the primary outcome analysis were recruited from 22 centres across 12 countries. bpMRI detected csPCa (GGG ≥2) in 143/490 (29.2%) compared to 145/490 (29.6%) on mpMRI (adjusted difference 0.4%; 95% CI -1.2 to 0.4; p=0.5). Results were consistent on a lesion-level analysis. bpMRI detected ciPCa (GGG 1) in 45/490 (9.2%) compared to 47/490 (9.6%) on mpMRI (adjusted difference 0.4%; 95% CI -1.2 to 0.4). bpMRI detected csPCa (GGG ≥3) in 73/490 (14.9%) compared to 75/490 (15.3%) on mpMRI (adjusted difference 0.4%; 95% CI -1.2 to 0.4).
Conclusion: In men with suspected prostate cancer, bpMRI with or without targeted biopsy was non-inferior to mpMRI in the detection of GGG 1, ≥2 or ≥3 prostate cancer.
Limitations: Radiologists were generally very experienced and scans were of good quality.
Funding for this study: The PRIME trial is supported by The John Black Charitable Foundation, Prostate Cancer UK, the European Association of Urology Research Foundation and Wolfgang.Dieckmann Foundation.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The UK National REC (West Midlands Black Country Research Ethics Committee, Nottingham) gave favourable approval for PRIME protocol V.2.0 on 28 June 2021 (ref: 21/WM/0091)

Author Block: S. Yu¹, J. Almeida², B. Whitcher¹, S. J. Withey¹, M. Blackledge¹, D-M. Koh¹, N. Papanikolaou², J. Winfield¹; ¹London/UK, ²Porto/PT
Purpose: Apparent diffusion coefficient (ADC) estimates from diffusion-weighted MRI (DWI) have shown good repeatability and ability to identify clinically-significant prostate cancer. Despite these findings, ADC values are not used quantitatively in clinical practice due to the lack of defined thresholds for interpretation and variation in ADC estimates between different imaging protocols. The impact of imaging protocol variations and inter-scanner differences on ADC estimates has not been quantified in large international datasets.
This study aims to model ADC values of the prostate, including variation with tumour grade, in a large multicentre dataset of DWI data to identify the imaging protocol and inter-scanner differences that affect ADC estimates.
Methods or Background: Mean ADC estimates of the prostate gland of 6413 patients from the ProCAncer-I repository including tumour grade and imaging metadata are used in the analysis. The whole prostate glands were segmented using methods developed in the ProCAncer-I project. A list of potentially significant imaging protocol parameters were compiled, based on literature review. Clinical data, including age, pathological Gleason Grade, and radiological PI-RADS scores were also collected.
Results or Findings: Random forest and Lasso regression identified significant factors using repeated 5-fold cross validation, with echo time, field of view, pixel spacing and PI-RADS=5 found consistently to be the most important factors correlating with ADC values. Lasso coefficients indicate that ADC value will change by -6.78, +98.58(10-6 mm2/s) per ms and mm increase in TE and pixel spacing, and +56.87, -34.84(10-6 mm2/s) for small-field-of-view scans and PI-RADS category 5, independently.
Conclusion: Using a real-world multi-centre prostate MRI dataset has allowed us to identify significant MR parameters and clinical factors that affect ADC estimates, which can inform on future multi-centre collaborations and protocol standardisation.
Limitations: N/A
Funding for this study: N/A
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information:

Author Block: L. Xu¹, F. Giganti², C. M. Moore², H. Sun³, X. Wang¹, L. Shi¹; ¹Hangzhou/CN, ²London/UK, ³Beijing/CN
Purpose: To evaluate the impact of a Prostate Imaging Quality (PI-QUAL) v2 lecture on accuracy and inter-reader agreement of prostate MRI image quality assessment among radiologists and technologists from diverse professional backgrounds and institutions, and to evaluate its role in institutional-level quality improvement through a quality control (QC) process.
Methods or Background: Ten participants (five radiologists and five technologists) from five different hospitals independently evaluated 15 prostate MRIs before and after a standardized PI-QUAL lecture. Reference scores were established by two experienced radiologists. Assessment accuracy was evaluated by the area under the ROC curve (AUC). Inter-reader agreement was measured using percent agreement (PA) and Gwet’s AC1. Subgroup analyses were conducted based on participant characteristics. For the quality assurance and QC (QA/QC), each center submitted 15 prostate MRIs before and after the lecture. Image quality was evaluated centrally to determine institutional improvement.
Results or Findings: The overall AUC improved from 0.629 to 0.842 (p < 0.001), with subgroup improvements across all participant types (pre: 0.500–0.688; post: 0.806–0.896). Inter-reader agreement improved from PA 57.6% to 72.6% and Gwet’s AC1 from 0.214 to 0.466. Through the QA/QC process, three centers initially failed to meet PI-QUAL v2 technical criteria. After feedback, image quality markedly improved, with all post-intervention scans achieving PI-QUAL v2 scores >1.
Conclusion: A structured PI-QUAL v2 lecture significantly improved both the accuracy and inter-reader agreement of prostate MRI image quality assessments among diverse evaluators. Incorporating QA/QC further enhanced institutional image quality. PI-QUAL v2 training is a feasible strategy for standardizing prostate MRI quality.
Limitations: First, the number of cases evaluated was limited. Second, no hands-on workshop was conducted.
Funding for this study: Not available.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the Institutional Review Board (IRB No. IRB-2025-683 (IIT)).

Author Block: G. Hang¹, R. Z. Lee¹, A. L. C. Y. Lai¹, N. Lath¹, J. Velaga², K. J. Tay¹, N. T. Ngo¹, Y. M. Law¹; ¹Singapore/SG, ²Brunswick East/AU
Purpose: The growing adoption of focal therapy (FT) for localized prostate cancer (PCa) emphasizes the need for standardized MRI-based frameworks to detect recurrent clinically significant prostate cancer (csPCa). The Transatlantic Recommendations for Prostate Gland Evaluation with MRI after Focal Therapy (TARGET) and Prostate Imaging after Focal Ablation (PI-FAB) systems have recently been proposed to guide post-FT multiparametric MRI (mpMRI) assessment. This study compared the diagnostic performance and inter-reader agreement of TARGET and PI-FAB.
Methods or Background: Patients who underwent FT for localized csPCa were recruited as part of a prospective phase II trial and an extended cohort. All patients underwent mpMRI and prostate biopsy. Two genitourinary radiologists evaluated post-FT mpMRI independently using TARGET and PI-FAB. Diagnostic metrics (sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV], accuracy) were analyzed. Inter-reader agreement was assessed using quadratic weighted Cohen’s kappa (κ).
Results or Findings: Seventy-nine patients with 139 ablated sites were included. For both TARGET and PI-FAB, radiologist 1 achieved the same sensitivity 100%, specificity of 82.6%, PPV of 62%, NPV of 100%, and an accuracy of 74.8%. Radiologist 2 achieved a sensitivity of 72.4% and 78.5%, a specificity of 65.4% and 64.8%, a PPV of 52.2% and 43.1%, an NPV 90% and 92.3%, and an accuracy of 66.9 % and 67.6% in TARGET and PI-FAB, respectively. Inter-reader agreement was moderate (κ=0.59 for TARGET, κ=0.60 for PI-FAB)
Conclusion: TARGET and PI-FAB demonstrated comparable diagnostic performance in detecting in-field recurrence of csPCa following FT. Despite different reader experience, moderate agreement was achieved, supporting their role in standardized post-FT mpMRI evaluation.
Limitations: This study was conducted at a single center with a modest sample size, which limits generalizability. Only two radiologists participated, restricting assessment of variability across broader expertise levels.
Funding for this study: Dr KJ Tay received funding support from National Medical Research Council, Singapore.
Grant number - NCT04138914.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Singapore General Hospital IRB

Author Block: Y. Chen, H. Wang, Y. Guo; Guangzhou/CN
Purpose: To investigate the feasibility of time-dependent diffusion MRI-based microstructural mapping for noninvasively characterizing the intraductal carcinoma (IDC) and invasive cribriform (Cr) histologic patterns in prostate cancer (PCa).
Methods or Background: This retrospective study enrolled men with pathologically confirmed PCa based on radical prostatectomy specimens between March 2023 and March 2025. Time-dependent diffusion MRI was performed using pulsed and oscillating gradient diffusion MRI sequences. The microstructural parameters, including cell diameter(d), extracellular diffusivity(Dex), intracellular fraction (fin), and cellularity were estimated with a two-compartment model. Apparent diffusion coefficient (ADC) maps were generated for each diffusion frequency (0 Hz, 17 Hz, 33 Hz). These parameters were compared between PCa with and without Cr/IDC patterns. Their diagnostic performance in detecting Cr/IDC architecture were assessed.
Results or Findings: A total of 81 participants were enrolled, of which 69.5% (57/81) PCa exhibited Cr/IDC patterns. Among all measurements derived from time-dependent diffusion MRI, fin and cellularity were significantly higher in the Cr/IDC-positive group compared to the negative group (P < 0.001 and P = 0.002, respectively), while ADC0Hz and ADC17Hz values were significantly lower (P = 0.015 and P = 0.029, respectively). No significant differences were observed in Dex, d and ADC33Hz (P = 0.151, 0.689, and 0.055, respectively). For detecting Cr/IDC morphology, fin yielded the highest area under the receiver operating characteristic curve (AUC) of 0.758 (95% CI: 0.639–0.877). Cellularity, ADC0Hz and ADC17Hz showed AUCs of 0.732 (95% CI: 0.605–0.858), 0.671 (95% CI: 0.545–0.798), and 0.654 (95% CI: 0.519–0.790), respectively.
Conclusion: Microstructural mapping via time-dependent diffusion MRI demonstrates strong potential for noninvasively characterizing histologic subtypes of PCa, showing high efficacy in identifying cribriform architecture and intraductal carcinoma.
Limitations: Sensitivity analyses adjusted for Gleason grade were not performed due to the small cohort.
Funding for this study: National Natural Science Foundation of China (82372075, 82371911, 82402415); Natural Science Outstanding Youth Fund Project of Guangdong Province (2024B1515020061); Youth Medical Innovation and Practice Research Program of Guangzhou (2023QNYXYB009)
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the institutional Medical Research Ethics Committee of the First Affiliated Hospital, Sun Yat-sen University.

Author Block: G. Agrotis, S. Ursprung, P. Van Leeuwen, H. Van der Poel, U. van der Heide, I. G. Schoots; Amsterdam/NL
Purpose: To systematically review and meta-analyze the prognostic value of pre-treatment MRI for oncological outcomes in men undergoing radical prostatectomy.
Methods or Background: A systematic literature search of MEDLINE, Embase, and Scopus was performed from inception through March 2025.
Eligible studies evaluated pre-treatment MRI in men undergoing radical prostatectomy and reported long-term oncological outcomes, including biochemical recurrence, metastatic failure, overall survival, or cancer-specific mortality. Two reviewers independently extracted data and assessed study quality using the Quality in Prognostic Studies tool. Random-effects meta-analysis was performed to pool hazard ratios (HRs). The primary outcome was biochemical recurrence. Secondary outcomes included metastatic failure and prostate cancer–specific mortality.
Results or Findings: Forty-four studies (27,453 patients) were included. MRI-detected extracapsular extension (mT3a disease) (HR 2.16 [95% CI, 1.85–2.52]) and seminal vesicle invasion (mT3b disease) (HR 3.32 [2.68–4.12]) were strong independent predictors of biochemical recurrence. PI-RADS score (HR 2.22 [1.86–2.64]) and tumor apparent diffusion coefficient values (HR 2.39 [1.65–3.47]) also showed prognostic value. Additional MRI features associated with recurrence included tumor diameter (HR 1.04 [1.01–1.07]), tumor volume (HR 1.56 [1.20–2.02]), peripheral zone tumor location (HR 3.64 [1.71–7.72]), and MRI-detected positive lymph nodes (HR 2.33 [1.78–3.04]). For metastatic failure, MRI-detected extracapsular extension (HR 4.11 [2.24–7.571]), seminal vesicle invasion (HR 8.36 [2.21–31.6]), and tumor diameter (HR 1.04 [1.02–1.06]) were independent predictors. MRI-detected extracapsular extension was also associated with prostate cancer–specific mortality (HR 7.86 [4.51–13.7]).
Conclusion: Pre-treatment MRI provides independent prognostic value for biochemical recurrence, metastatic failure, and cancer-specific mortality in men undergoing radical prostatectomy. Integration of specific MRI-derived predictors into risk models may improve preoperative stratification, guide treatment planning, and inform post-treatment management.
Limitations: retrospective, heterogeneity of MRI protocols and variability of readers
Funding for this study: No funding to disclose
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information:

Author Block: M. Boschheidgen¹, R. Al-Monajjed¹, A. Kilaviciute², J. P. Radtke¹, H-P. Schlemmer², G. Antoch¹, P. Albers¹, L. Schimmöller³; ¹Düsseldorf/DE, ²Heidelberg/DE, ³Herne/DE
Purpose: While MRI-guided targeted biopsy (TB) is becoming an integral part for early prostate cancer (PCa) detection, its role in screening of younger men remains unclear. Here we analyse the additional value of systematic biopsy (SB) to improve detection of clinically significant PCa (csPCa).
Methods or Background: 525 men aged 45–54 years with confirmed PSA ≥3.0 ng/ml underwent mpMRI followed by combined TB and SB between February 2014 and August 2023 within a multicenter, prospective screening trial in Germany. Software-based MRI/ultrasound fusion 2-core TB combined with SB was performed transrectally or transperineally. Primary objective was to analyse differences in csPC detection rates between SB versus TB in correlation to MRI. Secondary objectives were overall PCa detection and ISUP grade group (GG) distribution by SB and/or TB.
Results or Findings: PCa was detected in 209 men (39%). 148 were csPCa (71%; ISUP GG ≥2). SB missed 24 cases of csPCa (16%) and TB missed 49 (33%). SB detected 25 more low-risk PCa than TB (n=51 vs. n=26). In 64% of the cases in which SB detected a higher ISUP GG (n=89; including ISUP GG 1) the positive cores were located within the MRI-detected lesions. 5 ISUP GG ≥3 PCa were not identified on MRI.
Conclusion: A relevant proportion of csPCa was missed by 2-core TB although they were correctly identified on MRI, suggesting limitations in targeting accuracy and/or fusion technique. Thus, SB or at least perilesional sampling should become the standard biopsy technique in PCa detection in younger men until targeting can be further optimized.
Limitations: Limitations are the lack of centralized MRI review before biopsy, variability in biopsy technique, retrospective subgroup analysis, and short follow-up.
Funding for this study: Deutsche Krebshilfe
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethikkommission Düsseldorf

Author Block: L. Laschena, F. Mezzapesa, L. De Giacomo, S. Novelli, E. Messina, V. Panebianco; Rome/IT
Purpose: To explore the potential role of DWI in defining the "lesion-core" in the prostate peripheral zone and to assess whether targeting biopsies specifically on the DWI-based “lesion-core” can improve the diagnostic performance in detecting csPCa.
Methods or Background: Prospective,single-center study; patients with clinical suspicion of PCa underwent mpMRI according to PI-RADS v2.1 recommendations and those with a positive scan (PI-RADS 5, 4 and PI-RADS 3 with PSA-density ≥0.15) were directed to a transrectal-fusion-targeted-biopsy (TBx). Only peripheral zone lesions with a mismatch in terms of size or extent between DWI and T2WI were considered. During pre-biopsy lesion segmentation performed by an experienced uro-radiologist, the “lesion-core” was indicated as the most restricting area on DWI, while the “penumbra” as the exceeding area visible on T2WI.During the procedure cores from each region were collected and separately stored. Statistical analyses included McNemar’s,Wilcoxon, and ROC.
Results or Findings: 111 patients were enrolled;152 lesions identified.Overall, 12 (10.8%) had no evidence of prostate cancer, 18 (16.2%) had ciPCa, and 81 (72.8%) were diagnosed with csPCa.When stratifying by biopsy site, significant differences emerged between “lesion-core” and “penumbra".Detection of csPCa was higher in the lesion-core (107-70.3%) compared to the penumbra (79-52.0%), with a significant difference (p=0.01).Similarly, Gleason scores were higher in the lesion-core than in the penumbra.ROC analysis confirmed the superior diagnostic performance of lesion-core biopsies.The AUC for csPCa detection was 0.86 for lesion-core targeting compared to 0.66 for penumbra targeting, with the difference reaching statistical significance (p=0.031).
Conclusion: DWI-based lesion-core targeting provides higher diagnostic yield for csPCa compared to penumbra sampling. This approach refines biopsy accuracy, reduces overdiagnosis of indolent disease, and may improve patient stratification. DWI should therefore be considered the dominant sequence to guide targeted biopsy in peripheral zone lesions.
Limitations: Single-center study, sample-size
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: N/A

Author Block: F. Spoto¹, E. Demozzi¹, G. Sala¹, C. Cicciò¹, L. Monterubbiano¹, N. Cardobi², G. Cacciatori², M. D'Onofrio², G. Foti¹; ¹Negrar/IT, ²Verona/IT
Purpose: To quantify the impact of reader expertise on diagnostic accuracy for transition zone lesions using histopathological validation, and evaluate associated clinical and economic implications.
Methods or Background: This retrospective single-center study analyzed 315 consecutive patients with PI-RADS ≥3 transition zone lesions who underwent multiparametric MRI followed by MRI-guided in-bore biopsy between January 2018 and December 2024. Cases underwent blinded re-interpretation by either community radiologists (n=164) or expert readers at specialized center (n=151). Assessment included diagnostic accuracy metrics, PI-RADS category-specific performance, inter-observer agreement, and multivariable logistic regression. Economic impact was assessed through cost analysis and incremental cost-effectiveness ratios.
Results or Findings: Expert readers achieved superior diagnostic accuracy compared to community radiologists (47.0% versus 35.4%, p<0.001), representing 11.6% absolute improvement. Positive predictive value for clinically significant cancer improved 15.2% (43.3% versus 28.1%, p<0.001). For PI-RADS 4 lesions (56.8% of cohort), specialized centers achieved 76.9% cancer detection versus 42.6% for non-specialized centers (p<0.001), nearly doubling detection while reducing false positives by 60%. In multivariable analysis, PI-RADS score remained the strongest predictor (OR 3.06, p<0.001), while expertise effect was attenuated after adjustment (OR 1.12, p=0.68). Inter-observer agreement between experts (κ=0.603) exceeded agreement with community readers (κ=0.291, p=0.002). Economic analysis revealed €627 cost reduction per cancer detected through expert interpretation.
Conclusion: Reader expertise substantially impacts diagnostic accuracy for transition zone lesions, particularly for PI-RADS 4 lesions where specialized centers nearly double cancer detection rates while reducing false positives by 60%.
Limitations: Study limitations include retrospective design, potential selection bias, and lack of external validation. Economic analysis was limited to direct medical costs from a healthcare system perspective, without considering indirect costs or long-term treatment expenses beyond initial diagnosis.
Funding for this study: This study received no external funding.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information:

Author Block: R. C. Yarol, C. Sinirsiz, M. S. Ozer, I. B. Akin, O. Bozkurt, V. Sen, E. B. Tuna, K. Yorukoglu, C. Altay; Izmir/TR
Purpose: The aim of this study is to investigate the ability of the Node-RADS in predicting lymph node metastasis of prostate cancer.
Methods or Background: The Node-RADS score was provided a standized assessment of lymph nodes with scores ranging from 1 to 5, accounting size and configuration criteria. In thıs study, 102 patients with prostate cancer who have undergone radical prostatectomy and lymph node dissection from 2021 to 2025 were retrospectively evaluated for detection of lymph nodes and scored according to Node-RADS system. Node-RADS evaluations were performed by two radiologists based on pre-operative MR examinations. Diagnostic accuracy was assessed with receiver-operating characteristics (ROC) curve analysis, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Interreader agreement was calculated using Cohen’s kappa.
Results or Findings: Overall, 102 patients with a mean age of 67.26 ± 6.20 years were included. Lymph node metastasis was histopathologically proven 12 among 102 patients (11,8%). One patient with a score of 1 (1/80) and one patient with a score of 2 (1/8) had a positive node. Considering a Node RADS 4–5 positive and a Node RADS 1–2 negative, PPV was 85.7% and the NPV was 97.7%. Node-RADS achieved a sensitivity of 75% and a specificity of 98,8%. ROC curve analysis for lymph node discrimination showed an AUC of 0.897.
Conclusion: Node-RADS is a reliable and effective tool for predicting nodal metastasis in prostate cancer. Pre-operative routine use of it may enhance radiological staging and support treatment decisions.
Limitations: Retrospective nature and limited number of patients
Funding for this study: No funding
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study is approved by ethics committee.

Author Block: A. Dehghanpour, M. Bicchetti, A. Borrelli, S. Novelli, E. Messina, V. Panebianco, L. Laschena; Rome/IT
Purpose: Active surveillance (AS) is the recommended strategy for men with low-risk prostate cancer. The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) criteria were designed to standardise the reporting of tumour progression on serial MRI, and PRECISE v2 has recently refined definitions and incorporated minimum quality standards.
Multiple studies have demonstrated the non-inferiority of biparametric MRI (bpMRI) compared to multiparametric MRI (mpMRI) for the detection of csPCa. The aim of this study was to evaluate whether contrast administration can also be safely omitted in patients undergoing AS.
Methods or Background: We retrospectively analysed a prospectively maintained single-centre AS cohort of 185 men with clinically insignificant prostate cancer and ≥3 years of follow-up. 120 underwent repeat biopsy; the remainder were clinically and radiologically stable. Two expert radiologists independently reviewed all MRI examinations and assigned PRECISE v2 scores once using mpMRI and once using bpMRI. Image quality was scored with PI-QUAL v2. The reference standard was ISUP group grade on biopsy or stable follow-up. Diagnostic performance was assessed with ROC analysis for a PRECISE cut-off ≥4.
Results or Findings: For mpMRI, PRECISE ≥4 predicted ISUP upgrading with sensitivity 70%, specificity 75%, PPV 58%, NPV 84%, and accuracy 72% (AUC 0.77). In scans with PI-QUAL 3, particularly DWI score 4, bpMRI yielded comparable performance: sensitivity 66%, specificity 73%, PPV 55%, NPV 82%, accuracy 70% (AUC 0.75). When PI-QUAL was <3, bpMRI showed inferior performance with mpMRI significantly outperforming bpMRI (p<0.05).
Conclusion: PRECISE scoring system is an accurate tool for predicting disease progression in men on AS, both with mpMRI and bpMRI when image quality is optimal. However, in suboptimal scans mpMRI clearly outperforms bpMRI, and it is therefore not yet safe to omit contrast administration.
Limitations: Retrospective study.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Institutional Review Board and the Ethics Committee

Author Block: C. Elsner, A-M. Pausch, T. Rabadi, N. Rupp, D. Eberli, A. M. Hötker; Zürich/CH
Purpose: Optimal follow-up and biopsy stratification after high-intensity focused ultrasound (HIFU) ablation of localized prostate cancer are challenging, as PSA levels are often unreliable due to inflammation and variable residual tissue. This study aimed to evaluate the diagnostic performance of the Prostate Imaging after Focal Ablation (PI-FAB) score on multiparametric MRI in combination with volume-adjusted PSA density (vaPSA-D, derived from volumetrically assessed residual vital prostate tissue) in recurrence detection.
Methods or Background: This IRB-approved, retrospective single-center study included 119 men treated with HIFU for localized prostate cancer. Follow-up mpMRI and prostate biopsies were performed at 6, 12, and 36 months. PI-FAB scores and vaPSA-D were assessed independently. Diagnostic performance was analyzed using histopathology from biopsy as the reference standard.
Results or Findings: The PI-FAB score demonstrated good diagnostic performance, particularly at 36 months (AUC 0.92). VaPSA-D likewise showed solid performance, with steadily increasing accuracy over time (AUC 0.68, 0.81, 0.84 at 6, 12, and 36 months; overall 0.78), outperforming PI-FAB at 12 months post-HIFU. Integrating vaPSA-D into PI-FAB subgroups significantly enhanced recurrence assessment: PI-FAB 1: sensitivity/specificity 75%/78% (threshold 0.14 ng/ml); PI-FAB ≥2: sensitivity/specificity 67%/85% (threshold: 0.18 ng/ml); PI-FAB 3: sensitivity/specificity 69%/90% (threshold: 0.18 ng/ml).
Conclusion: Both PI-FAB and vaPSA-D perform well in the post-HIFU setting, each with distinct strengths: PI-FAB shows excellent performance at late follow-up, while vaPSA-D ensures high sensitivity and reliable recurrence exclusion across all time points. Their combined application provides the most accurate assessment of in-field recurrence after HIFU, supporting a complementary rather than exclusive use of these tools to potentially reduce unnecessary biopsies.
Limitations: Limitations include the retrospective design, single-center setting, and an overall low recurrence prevalence.
Funding for this study: No funding for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Cantonal ethics committee Zurich

Author Block: G. Hang¹, R. Z. Lee¹, A. L. C. Y. Lai¹, N. Lath¹, J. Velaga², K. J. Tay¹, N. T. Ngo¹, Y. M. Law¹; ¹Singapore/SG, ²Brunswick East/AU
Purpose: Architectural distortion after focal therapy (FT) presents challenges for post-treatment surveillance using multiparametric magnetic resonance imaging (mpMRI). To address this, the Transatlantic Recommendations for Prostate Gland Evaluation with Magnetic Resonance Imaging After Focal Therapy (TAREGT) scoring system—a 5-point scale—was recently developed to evaluate residual cancer or in-field recurrence at ablation sites. This study aimed to assess the diagnostic performance and inter-rater reliability of the TARGET system in post-FT mpMRI.
Methods or Background: Patients were enrolled through a phase II clinical trial and an extended prospective cohort. Eligible participants had localized clinically significant prostate cancer (csPCa) and underwent cryotherapy or irreversible electroporation (IRE) between October 2019 and January 2024. All underwent post-FT mpMRI and subsequent prostate biopsy. Two genitourinary radiologists with 11 and 5 years of experience independently assessed mpMRI using TARGET. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated. Inter-rater reliability was measured with quadratic weighted Cohen’s kappa (κ).
Results or Findings: Seventy-nine patients with 139 treated sites were analyzed. Radiologist 1 achieved sensitivity 100 %, specificity 82.6 %, PPV 62 %, NPV 100 %, and accuracy 74.8 %. Radiologist 2 achieved sensitivity 72.4 %, specificity 65.4 %, PPV 52.2 %, NPV 90 %, and accuracy 66.9 %. Cohen’s κ was 0.59, indicating moderate agreement.
Conclusion: The TARGET scoring system demonstrated high diagnostic accuracy in detecting in-field recurrence after FT. Despite moderate inter-reader agreement, diagnostic performance was higher for the more experienced radiologist, highlighting the influence of expertise. These findings support TARGET as a valid framework for standardized post-FT mpMRI surveillance.
Limitations: This study was conducted at a single center with a modest sample size, which may limit generalizability. Only two radiologists participated, restricting assessment of variability across broader expertise levels.
Funding for this study: Dr KJ Tay received funding support from National Medical Research Council, Singapore.
Grant number - NCT04138914.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study has been approved by Singapore General Hospital IRB