RPS 407 - What's new in prostate imaging: advances and emerging techniques

Author Block: L. Russo¹, S. Bottazzi¹, O. Longoria², G. Avesani¹, S. J. Withey², L. D'Erme¹, E. Sala¹, D-M. Koh², N. Tunariu²; ¹Rome/IT, ²London/UK
Purpose: Treatment response assessment in metastatic castration-resistant prostate cancer (mCRPC) is critical because the Prostate Cancer Working Group 3 (PCWG3) criteria have notable limitations. The METastasis Reporting and Data System for Prostate Cancer (MET-RADS-P) provides standardised guidelines using whole-body MRI (WBMRI). Our main aim was to compare MET-RADS-P and PCWG3 criteria for disease progression categorization in mCRPC, as well as the prognostic value of MET-RADS-P for progression-free survival (PFS) and overall survival (OS).
Methods or Background: A cohort of 201 mCRPC patients treated at The Royal Marsden Hospital between January 2013 and February 2024 was retrospectively included. All patients underwent WBMRI, CT and BS at each time point. CT and BS were interpreted according to PCWG3 and WBMRI according to MET-RADS-P. Concordance between MET-RADS-P and PCWG3 in disease progression categorization was assessed overall, in bone and soft-tissue only. PFS and OS were evaluated using Kaplan-Meier survival curves with log-rank test comparisons.
Results or Findings: Overall, 64.5% of time points (302/468) were concordant between MET-RADS-P and PCWG3 criteria, with MET-RADS-P detecting progression earlier in 31.8% (149/468). Discrepancies were more pronounced in bone metastases, where MET-RADS-P identified progression in 55.1% of cases classified as non-progressive disease by PCWG3.
Progressing patients by MET-RADS-P had significantly worse PFS: median 2.7 months versus 4.2 months by PCWG3 (p<0.001). The median OS was 12.5 months for progressing patients by MET-RADS-P at 12-week assessment compared to 19.8 months for those stable or responding (p<0.001).
Conclusion: MET-RADS-P allowed for earlier progression detection compared with PCWG3, particularly in bone metastases, potentially permitting earlier therapeutic interventions. MET-RADS-P also demonstrated strong predictive value for PFS and OS, suggesting its potential role as an imaging biomarker in future clinical trials.
Limitations: Retrospective design and lack of cost and availability comparative analysis.
Funding for this study: This study represents independent research funded by the National Institute for Health and Care Research (NIHR) Biomedical Research Centre at The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research, London, and by the Royal Marsden Cancer Charity, and Cancer Research UK (CRUK) National Cancer Imaging Trials Accelerator (NCITA) and Prostate Cancer UK. The views expressed are those of the author(s) and not necessarily those of the NIHR or the Department of Health and Social Care. This work uses data provided by patients and collected by the NHS as part of their care and support.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the Institutional Ethics Committee (reference no. 21/LO/0605).

Author Block: M. Boschheidgen¹, R. Al-Monajjed¹, J. P. Radtke¹, H-P. Schlemmer², G. Antoch¹, L. Schimmöller¹, P. Albers¹; ¹Düsseldorf/DE, ²Heidelberg/DE
Purpose: To analyze the performance of targeted (TB) and systematic (SB) MRI/US fusion-guided prostate biopsy within the prospective PROBASE prostate cancer (PC) screening trial.
Methods or Background: Men aged forty-five from the general population were invited to screening. Those with confirmed prostate-specific antigen (PSA) levels of 3 ng/ml or higher were offered an MRI and were referred to MRI/US-guided biopsy. Biopsies were performed in every participant unrespective of the MRI result. Targeted and systematic biopsies with software-based fusion techniques were offered. The primary endpoint of this analysis was the PC detection in either TB or SB.
Results or Findings: A total of 554 men (median age 50 (range 44-54), median PSA level 4.1 ng/ml) were analyzed who underwent an MRI followed by MRI/US-guided biopsy. Of 217 PC diagnosed, 198 (91%) and 140 (65%) were detected by SB and TB, respectively. 64 of 217 PC (29%) were low grade (ISUP 1). 40 significant tumors were found exclusively by SB (26%), while 9 significant tumors were only diagnosed with TB (6%). SB detected significantly more low-grade cancer compared to TB (p<0.001). Cancer detection rate was 20% for PIRADS 1-2, 26% for PIRADS 3, 59% for PIRADS 4, and 92% for PIRADS 5.
Conclusion: In young men and in the setting presented here, systematic biopsy in addition to targeted MRI/US guided fusion biopsy still appears to be justified to adequately detect PC. Most PC (71%) were clinically significant. Performing only TB in young men without SB faces the risk of missing a significant number of csPC even if it simultaneously diagnoses fewer low-grade carcinomas.
Limitations: MRI did not influence clinical decision-making; experience in MRI reading and the image quality differed widely at the time of initiation
Funding for this study: Deutsche Krebshilfe
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by local ethics committee.

Author Block: M. D. M. Palma, D. Freire Maia Vieira, T. A. Leite De Lima, J. Nather, F. Chahud, R. B. Reis, V. F. Muglia; Ribeirao Preto/BR
Purpose: Cribriform pattern (CP) is a distinct histological feature present in various neoplasms, characterized by cohesive tumour cells surrounding circular spaces, creating a "Swiss cheese" appearance. In prostate cancer (PCa), CP is one of the four architectural subtypes of the Gleason 4 pattern and has been linked to worse outcomes compared to other morphologies. This study aimed to determine if CP presents distinct features on multiparametric magnetic resonance imaging (MRI).
Methods or Background: In this retrospective, single-centre study, we identified PCa cases with CP from 2016 to 2023, with MRI conducted within four months of histological diagnosis. Patients without CP but with equivalent Gleason grades and risk stratification were included as controls in a ratio of up to 1.5:1. Two radiologists, with over 5 and the other with 7 years of prostate imaging experience, evaluated lesion size, form, location, prostate volume, mean apparent diffusion coefficient (ADC) values, and post-contrast kinetic curves. Clinical staging, prostate-specific antigen (PSA), and PSA density (dPSA) were also reviewed.
Results or Findings: The study included 42 patients with CP and 72 without CP. No significant differences were found between the groups regarding PSA (p=0.43), dPSA (p=0.37), lesion size (p=0.33), location (p=0.65), mean ADC (p=0.21), or kinetic curve type (p=0.75). Significant differences were observed for age (p<0.0001), prostate volume (p=0.001), and PI-RADS category (p=0.05). In univariate logistic regression, age and PI-RADS score were independent predictors of CP presence, but only age remained significant in multivariate analysis (p=0.0001).
Conclusion: Cribrifrom pattern in PCa is more common in older men with larger prostates and higher PI-RADS scores. However, no specific morphological or functional MRI parameters were associated with the presence of this pattern.
Limitations: Single-centre, retrospective study.
Funding for this study: None
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: Our Institutional Review Board approved the research with a waiver for informed consent due to the retrospective nature.

Author Block: S. Durmaz¹, S-C. J. Wu², K-L. Lee², A. Shakur², I. Caglič², T. Barrett²; ¹Istanbul/TR, ²Cambridge/UK
Purpose: To evaluate the impact of PSA density (PSAd) on the probability of detecting clinically significant prostate cancer (csPCa) across different prostate volume ranges and PI-RADS scores.
Methods or Background: 2097 patients undergoing multiparametric MRI (mpMRI) for suspected PCa were included. 738/2097 (35.2%) had PCa, and 566/2097 (27%) had csPCa (Gleason ≥3+4), patients were classified as negative after biopsy (n=299) or were diagnosed with clinically insignificant PCa (n=172) or having a negative mpMRI and completing at least one-year follow-up without developing PCa (n=1060). Single-variable logistic regression analyses were conducted to assess the impact of PSAd on the probability of csPCa within the different prostate volume ranges (<40 mL, 40-60 mL, 60-80 mL, >80 mL) and PI-RADS groups.
Results or Findings: The median age, PSA, PSAd, and prostate volume was 66 years (IQR: 61-72), 5.6 ng/mL (IQR:4.05-8.05), 0.10 ng/mL/mL (IQR:0.07-O.15), and 56 mL (IQR:39-80), respectively. Logistic regression at a PSAd of 0.15 ng/mL/mL showed the probability of csPCa decreased with increasing prostate volume: <40 mL (44%), 40-60 mL (38%), 60-80 mL (29%), and >80 mL (18%). At the same PSAd level, the probability of csPCa increased with increasing PI-RADS score: PIRADS 1-2 (3%), PI-RADS 3 (26%), PI-RADS 4 (63%), PI-RADS 5 (70%). Regardless of the PSAd level, the risk of csPCa in patients with PI-RADS 4-5 lesions was always >20%.
Conclusion: When using PSAd to assist in the decision to perform MRI, or to biopsy patients with PI-RADS 1-3 scores, caution should be exercised in those with larger volume prostates, as the lower PSAd can provide false reassurance.
Limitations: Retrospective design. All patients underwent mpMRI and prostate biopsy at a single tertiary referral center with extensive experience in prostate MRI and biopsy.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: This is a retrospective study.

Author Block: F. Li¹, L. Zhuo¹, L. Yue¹, L. Juan¹, L. Wang¹, R. Liu¹, F. Wang², Y. Xiang³; ¹Mianyang City/CN, ²Luzhou/CN, ³Leshan/CN
Purpose: The purpose of this study is to develop and verify a deep learning model using preoperative multi-parameter MRI images to predict BCR risk after radical prostatectomy.
Methods or Background: Patients after radical surgery at 4 centers between August 2013 and September 2021 were retrospectively included with the endpoint outcome of 3-year BCR (two consecutive specific antigen [PSA] levels > 0.2 ng/mL [0.2µg/L]). A transformer-based DL model was used to predict BCR after radical surgery using 3D tumor images, a clinical model was constructed by multivariate logistic regression, Kaplan-Meier plots were used for estimating recurrence-free survival, and finally, pre- and post-surgical Capra models, a clinical model, a multi-instance model, and a transformer model, Multimodal Combine model were compared to assess the performance of predicting BCR.
Results or Findings: A total of 582 patients (median age 70 years, (IQR 44-89 years) with a median follow-up of 43 months (IQR, 29-71 months) were randomized into a training group (n=249 ), an internal test set (n=107), an external test set 1 (n=189), and an external test set 2 (n=37).The AUC of the Transformer model in the 0.92 in the internal test set, 0.84 in the external test set 1, and 0.82 in the external test set 2, and the multimodal Combine model further improves the performance, respectively, with 0.94 (95% CI. 0.885 - 0.992), 0.94 (95% CI, 0.900 - 0.969), and 0.83 (95% CI, 0.693 - 0.965), and early recurrence-free survival and overall survival could be better risk-stratified and predicted using the Combine model.
Conclusion: A transformer-based DL model for predicting BCR after radical surgery was developed and internally and externally validated, and the joint model is better and expected to guide individualized treatment.
Limitations: Not applicable.
Funding for this study: No funding was provided for this study
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics （2024）014-1

Author Block: C. Peter, A. Schaudinn, C. Ehrengut, T. Franz, L-C. Horn, N. Linder, J-U. Stolzenburg, H. Busse, T. Denecke; Leipzig/DE
Purpose: To evaluate the image quality of a rapid intraprocedural balanced steady-state free precession (b-SSFP) sequence for re-identification of prostate lesions during transrectal in-bore biopsies in comparison with that of a T2-weighted
Methods or Background: In this retrospective study, 127 patients with 140 PI-RADS ≥ 3 (version 2.1) lesions based on multiparametric 3T MRI (mpMRI) underwent transrectal in-bore biopsies. b-SSFP images were acquired at 1.5T for interventional guidance. Two radiologists (R1: 11 years and R2: 2 years of mpMRI experience) independently rated the image quality of both b-SSFP (acquisition time: 11-15 seconds) and diagnostic T2-weighted TSE (3T, acquisition time: 4-5 minutes) sequences using a 4-point scale (3: good, 2: acceptable, 1: poor, 0: impossible for lesion identification). Recognition rates (RR) were calculated as the percentage of cases with sufficient image quality (scores of 3 or 2). Subgroup analyses were performed by zonal location (PZ/TZ), lesion size (Results or Findings: The RR for the T2-weighted reference sequence was 98% for both radiologists, with subgroups ranging from 94% to 99%. For b-SSFP, the RR was 87% for R1 and 81% for R2, with subgroups ranging from 75% (PI-RADS 3) to 92-93% (PI-RADS 4/5, large lesions). No significant differences were found between readers. RR differences between sequences were statistically significant, except for TZ and large lesions rated by R1.
Conclusion: b-SSFP showed only moderately lower RR than the very high RR of T2-weighted reference images, especially for the experienced reader R1. Given its much shorter acquisition time, b-SSFP of discernible lesions therefore has the potential to reduce biopsy times, particularly for large or (highly) suspicious lesions (PI-RADS 4-5).
Limitations: Retrospective; single-center.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics committee was consulted, written informed consent was obtained from participating patients

Author Block: P. N. Franco, C. R. G. L. O. M. Talei Franzesi, C. Maino, R. Corso, D. Ippolito; Monza/IT
Purpose: To investigate the diagnostic value of diffusion-weighted (DWI) MRI early changes, 1 hour after treatment, in patients with organ-confined unfavourable prostate cancer (PCa) treated with Single-Dose Ablative Radiation Therapy (SDART), in comparison with biochemical markers.
Methods or Background: Twenty-four patients with intermediate unfavourable or high-risk localized PCa treated with SDART (21 Gy on the entire prostate with boost up to 24 Gy on the focal lesion) associated with hormone therapy were prospectively enrolled. Each patient was examined with a 3T scanner four times: (1) 1-2 weeks before RT (t0) for treatment planning; (2) 1 hour after treatment (t1); (3) 3 months after treatment (t2); (4) 2 years after treatment (t3). Regions of interest (ROIs) were plotted on apparent diffusion coefficient (ADC) maps and T2-HR sequences on lesions, benign peripheral zone, and the entire prostate gland. Patients’ laboratory data (PSA and testosterone) was collected.
Results or Findings: ADC values significantly increased in neoplastic lesions at t1, t2 and t3 (+22%, +43% and +53%, respectively). Conversely, no significant changes were observed in the benign peripheral zone and the entire prostate gland. On T2 sequences, signal intensity progressively decreased in the benign peripheral zone (t1: -1%; t2: -33%; t3: -42%) and in the entire prostate gland (t1: -6%; t2: -24%; t3: -31%), while no significant changes were observed in lesions. All patients except one had a complete biochemical response.
Conclusion: The study findings showed high diagnostic value of DWI and a good correlation between early (t1) changes in ADC values after SDART and later (t2 and t3) tumour response (both biochemical and imaging) in patients with unfavourable PCa. Early DWI changes can represent a useful parameter to evaluate treatment response and predict patients’ outcomes.
Limitations: Small sample size; associated hormone therapy.
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The local ethics committee formally approved this study.

Author Block: F. Porões, A. Nobile, L. Widmer, J. A. Vidal, J. Di Vincenzo, H. Najberg, J. M. M. Froehlich, C. Reischauer, H. Thoeny; Fribourg/CH
Purpose: We introduce a new parameter for predicting extraprostatic extension (EPE) on multiparametric magnetic resonance imaging (mpMRI): the maximal radial distance (maxRADD). It corresponds to the largest diameter of a prostate cancer focus (PCF) perpendicular to a contact with the prostate pseudocapsule. We compare accuracy and reproducibility of maxRADD with the previously proposed maximal capsular contact length (maxCCL) for predicting EPE.
Methods or Background: We retrospectively and consecutively included 81 patients undergoing prostate mpMRI between October 2018 and December 2020, followed by radical prostatectomy. One uropathologist with 8 years of experience collected for each PCF: location, maxCCL, maxRADD, and presence/absence of EPE. Four radiologists with 0, 2, 3, and 6 years of experience in prostate mpMRI determined maxRADD and maxCCL on mpMRI for each PCF twice in separate readings. Accuracy in predicting EPE was assessed using the area under the curve (AUC), with the pathologic findings as the gold standard. Inter-/intra-reader agreement were assessed using intraclass correlation coefficients (ICCs) and Cronbach’s alpha.
Results or Findings: On histolpathology, there was no significant difference in the accuracy of predicting EPE between maxRADD and maxCCL (AUCmaxRADD = 0.92, AUCmaxCCL = 0.91, p = 0.28). Pearson correlation showed a strong correlation of both parameters determined on mpMRI with their histopathological counterparts (>0.7), with the exception of maxCCL assessed by the reader w/o experience in prostate mpMRI (0.54). On mpMRI, inter-reader agreement was significantly higher for maxRADD (ICCmaxRADD = 0.96, ICCmaxCCL = 0.94, p = 0.046) and intra-reader agreement was higher but did not reach significance (average alphamaxRADD = 0.95, average alphamaxCCL = 0.92, p = 0.31).
Conclusion: MaxRADD permits assessing EPE with good accuracy and shows higher reproducibility compared with maxCCL.
Limitations: No significant limitation.
Funding for this study: This study has received funding by the Swiss National Science Foundation (Grant/Award Number: 32003B_176229/1) and the HFR Research GRANT (2352).
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by our institutional ethics committee (CER-VD). The ethics committee notification can be found under the project-ID 2020-01859.

Author Block: G. Brembilla, D. Cannoletta, M. Cosenza, F. Pellegrino, M. E. Porzi, L. Quarta, A. Stabile, A. Briganti, F. De Cobelli; Milan/IT
Purpose: To assess the impact of image quality, defined by PI-QUAL v2 scores, on the diagnostic yield of prostate MRI in centrally reviewed scans.
Methods or Background: We retrospectively identified consecutive patients who underwent MRI-targeted and systematic biopsies at our Institution (January 2023 - June 2024), with MRI performed externally. All the external MRI scans were centrally reviewed by an experienced uro-radiologist, who assigned PI-QUAL v2 and PI-RADS v2.1 scores. We assessed the proportion of PI-RADS 3 lesions and the detection rate of clinically significant prostate cancer (csPCa), stratified by PI-QUAL v2 scores, before and after central revision. Histopathological results from the biopsies were used as the reference standard.
Results or Findings: A total of 151 consecutive patients were included in the analysis. 37/151 (24%) of the MRI scans were scored PI-QUAL 1, 72/151 (48%) PI-QUAL 2, and 42/151 (38%) PI-QUAL 3.
Based on original reports, the overall proportion of PI-RADS 3 scans was 34/151 (23%). In PI-QUAL 1-2 vs 3 scans, the proportion of PI-RADS 3 in was 27% vs 12%, respectively; the csPCa detection rate was 48% vs 62%, respectively.
The reclassification rate of PI-RADS scores at central review was 64/151 (42%), and was higher for PI-QUAL 1-2 scans (47%) than for PI-QUAL 3 scans (31%). After central revision, the overall proportion of PI-RADS 3 in PI-QUAL 1-2 vs 3 was 19% vs 5%, respectively; the detection rate of csPCa was 58% vs 78%, respectively.
Conclusion: Lower prostate MRI image quality, as defined by the PI-QUAL v2 scoring system, is associated with a higher proportion of equivocal scans (PI-RADS 3) and a reduced csPCa detection rate in centrally revised MRI scans.
Limitations: Small sample size, only one radiologist for review
Funding for this study: None
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: IRB approved

Author Block: J. Uhlig, L. Biggemann, C. Louizi, A. Uhlig; Göttingen/DE
Purpose: To evaluate differences in prostate volume quantification on MRI comparing full manual segmentation and PIRADS-based approximation in 2 planes.
Methods or Background: Patients imaged with 3T mpMRI (Siemens VIDA) for suspected prostate cancer between 2021-2023 were included. PSA measurements were obtained at the time of mpMRI or extracted from patients records up to 3 months prior. Manual segmentation of the prostate was performed on all axial T2w slices serving as reference standard. Prostate volume was approximated using 3 measurements on T2w sagittal and axial planes according to the PIRADSv2.1 recommendations. Prostate volumes from manual segmentation and approximation were compared and the influence on PSA-density quantified using different cut-off values.
Results or Findings: n=331 patients were included (mean age 67 ± 7 years) with a mean PSA value of 8.1 ± 5.7 ng/ml.
Mean prostate volume using manual segmentation was 63.3cc (± 33cc), with n=142 patients having a volume of <=50cc, 51-100cc: n=148, 101-150cc: n=32, and >151cc: n=8. The mean absolute difference of prostate volume using approximation vs. segmentation was 9.1cc (±9.3cc, p=0.01). In general, smaller prostate volumes were overestimated, and larger volumes underestimated by approximation.
Using a PSA-density cut-off <0.1 ng/ml/cc, the approximation method yielded an accuracy = 88%. Using a PSA-density cut-off <0.15 ng/ml/cc, the approximation method yielded an accuracy = 90%.
Conclusion: Using PIRADSv2.1-based approximation of prostate volume on mpMRI yields a statistically significant difference when compared to full manual segmentation. These differences have a relevant effect on PSA-density calculation with potential impact on downstream patient management.
Limitations: Patients were recruited in only one tertiary center and imaged on one MRI scanner, which could limit the generalizability of presented results.
Funding for this study: This study received no funding.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: Ethics committee of the University Medical Center Goettingen

Author Block: E. Messina, A. Borrelli, L. Laschena, S. Lucciola, M. Pecoraro, V. Panebianco; Rome/IT
Purpose: PROSA is a randomized MRI-based screening protocol, investigating the role of MRI without contrast media injection (bi-parametric MRI, bpMRI) as secondary prevention test for prostate cancer (PCa) early diagnosis, comparing MRI with PSA-test. PROSA aims to investigate the efficiency of this screening protocol, both in terms of diagnostic accuracy, and cost-effectiveness.
Methods or Background: 590 men aged 49 to 69 years were enrolled and blindly randomized into two different arms:
(A) Men underwent bpMRI regardless of their PSA values;
(B) Men with increased PSA were directed to bpMRI, while those with normal PSA were not.
Men screened positive on MRI were directed to MR-directed targeted biopsy.
To evaluate the efficiency of the protocol we calculated the experimental event rate (EER), control event rate (CER), absolute risk reduction (ARR), number needed to treat (NNT).
Health Technology Assessment analysis was implemented to evaluate the cost-effectiveness. The cost/effectiveness ratio is calculated as follows: Delta Costs/ Delta effectiveness = (CA–CB)/(EA-EB).
Results or Findings: 289 men were randomized on Arm A and among them 15 clinically significant PCa (csPCa) were detected; 291 men were randomized on Arm B, with 6 csPCa detected (p=0.04).
On arm A, 8 men diagnosed with csPCa (53.3%) presented normal PSA levels.
Considering the efficiency of the screening protocol, EER was 5.23%, CER 2.06%, ARR 3.17%, and NNT 31.6. Therefore 32 interventions (in this study MRIs) are needed to find one event (in this study one csPCa).
The final cost/effectiveness ratio resulted to be € 3.562,61 for the diagnosis of one csPCa.
Conclusion: Prostate MRI without contrast media injection showed promising results compared to the use of PSA analysis alone as a screening tool, both in terms of efficiency and cost-effectiveness.
Limitations: Single center
Funding for this study: No
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: CE Approved