Faculty Bibliography

INTRODUCTION/BACKGROUND:Focal dose intensification strategies targeting the dominant intra-prostatic lesion (DIL) improve outcomes of patients with prostate cancer. The purpose was to determine whether the 6-month multiparametric (mp)MRI response of the DIL is associated with post-treatment prostate-specific antigen (PSA) kinetics after MRI linear accelerator (LINAC) guided stereotactic body radiotherapy (SBRT) with focal dose intensification. METHODS:), and PSA ≤ 1.0 ng/mL. RESULTS:(100.0% vs 82.9%, p = 0.010) and PSA ≤ 1.0 ng/mL (45.9% vs 11.4%, p = 0.001) compared to those without mpMRI CR. In 10 patients without 6-month mpMRI CR but had further MRI follow-up (median 13 months), DILs either further decreased in size (30.0%) or resolved (70.0%). CONCLUSION/CONCLUSIONS:Initial 6-month mpMRI response correlates with PSA kinetics, which is associated with important clinical outcomes. mpMRI can be used for post-SBRT evaluation to gauge local tumor response of the DIL, where most recurrences occur.

High-quality bladder MRI is essential for reliable detection and characterization of bladder tumors. While the Vesical Imaging Reporting and Data System (VI-RADS) was developed to standardize acquisition, interpretation, and reporting of MRI for bladder cancer staging, no universal scoring system has been established for quality assessment. A systematic review showed that existing efforts for bladder MRI quality assessment have largely relied on study-specific, subjective Likert-type scales, with substantial variability, hindering reproducibility and comparability across studies and institutions. In this paper, we describe a novel bladder MRI scoring system that was developed by the multidisciplinary American College of Radiology VI-RADS Steering Committee, the VI-RADS Quality Score. It provides stratification of quality scores-inadequate, adequate, and optimal-based on signal-to-noise ratio, ability to clearly visualize relevant anatomic landmarks, and assessments of common imaging artifacts, which can guide clinical decision-making. It also emphasizes per-sequence scores in addition to an overall assessment to support targeted MRI protocol optimization. The VI-RADS Quality Score will need to be prospectively validated and will facilitate reproducibility across institutions, build trust in bladder MRI within multidisciplinary teams, and accelerate widespread adoption of bladder MRI for bladder cancer imaging. KEY POINTS: Question While high-quality bladder MRI is essential for evaluating bladder cancer, no universal scoring system is established for quality assessment. Findings A systematic review showed that studies on bladder MRI quality had significant variability. A structured scoring system was developed by the multidisciplinary VI-RADS steering committee. Clinical relevance High-quality bladder MRI is essential for reliable evaluation of bladder cancer. The VI-RADS Steering Committee developed a scoring system for bladder MRI quality assessment. This is expected to facilitate reproducibility and build trust in bladder MRI within multidisciplinary teams.

OBJECTIVE:Indeterminate lesions on prostate-specific membrane antigen (PSMA)-PET are challenging to address. We aimed to develop, implement, and evaluate a multidisciplinary consensus algorithm that integrates existing interpretation systems with multimodality imaging and clinicopathological information for interpreting indeterminate bone and lymph node lesions on PSMA-PET. MATERIALS AND METHODS/METHODS:This was a retrospective single-center study on a prospectively implemented algorithm. We included all consecutive prostate cancer patients whose PSMA-PET findings for indeterminate bone lesions or lymph nodes were discussed at a multidisciplinary tumor board (MDT) in 2024-2025. An algorithm determining the level of suspicion for metastasis was developed in a multidisciplinary fashion, incorporating lesion location, conventional imaging features, PSMA-PET characteristics, and clinicopathological information. The application of the algorithm and outcomes were documented, compared against a composite reference standard. Comparisons were made with PSMA-RADS and PROMISE V2 PSMA-expression scores. RESULTS:81 patients (median age 68, interquartile range 64-75) were included. Algorithm results were benign (48.1% [39/81]), equivocal (4.9% [4/81]), metastasis (40.7% [33/81]), and mixed (benign and metastatic lesions, 6.2% [5/81]). The algorithm was correct in 94.1% (64 of 68 patients with a sufficient reference standard). The algorithm was discordant with PSMA-RADS in 54.3% (44/81) and with PROMISE V2 PSMA-expression score in 71.6% (58/81). The frequency of equivocal lesions was lower using the algorithm (4.9% [4/81]) compared with PSMA-RADS (53.1% [43/81]) and PSMA-expression score (64.2% [52/81]). CONCLUSION/CONCLUSIONS:A multidisciplinary consensus algorithm for interpreting indeterminate bone lesions and lymph nodes on PSMA-PET was developed and implemented. Integrating clinicopathological information and multimodality imaging in an MDT setting reduced equivocal interpretations. KEY POINTS/CONCLUSIONS:Question While prostate-specific membrane antigen (PSMA)-PET has become essential in the management of prostate cancer, indeterminate bone lesions and lymph nodes remain challenging to address. Findings A multidisciplinary algorithm for interpreting indeterminate bone lesions and lymph nodes on PSMA-PET, incorporating clinicopathological information and multimodality imaging, reduced the frequency of equivocal interpretations. Clinical relevance An algorithm for interpreting indeterminate bone lesions and lymph nodes on PSMA-PET, incorporating clinicopathological information and multimodality imaging in a multidisciplinary tumor board setting, decreases the frequency of equivocal interpretations and can potentially help management decisions.

Post-radiotherapy erectile dysfunction (ED) can significantly impact the quality of life of patients with prostate cancer (PCa). Critical anatomical structures, such as the neurovascular bundle (NVB), internal pudendal arteries (IPA), penile bulb, and corporal tissues track in close proximity to the prostate, making them susceptible to radiation-related damage. This study aimed to evaluate the anatomical patterns of these structures and their relationship with the prostate, and to provide comprehensive illustrative examples on MRI. Consecutive patients with PCa who underwent MRI-linear accelerator (LINAC)-based stereotactic body radiotherapy (SBRT) in January-December 2024 were included. NVB patterns were classified into 3 categories: (1) "classical" with discrete NVB elements, (2) "adherent", dispersed and adherent to prostatic capsule, and (3) "absent". The smallest distance between the IPA and the prostate capsule and membranous urethral length (MUL), serving as a surrogate for distance between corporal tissue and prostatic apex, were also measured. These MRI findings were compared between prostate volumes >40 and <40 ml and between MRI/pathological features of the dominant intraprostatic lesion. A total of 160 men (median age 70 years, interquartile range [IQR] 64-76) were included. The most common NVB pattern was "classic" (80.0-85.0%), followed by the "adherent" NVB pattern (13.8-18.1%). The median smallest distance between the IPA and prostate was 2.3 cm (IQR 1.8-2.8 cm), with 3.1-3.8% less than 1.0 cm. The median MUL was 1.5 cm (IQR, 1.2-1.8 cm), with 2.5% of patients less than 1.0 cm. No significant association was found between these MRI features and prostate volume or other variables (p = 0.09-0.99). In conclusion, most PCa patients demonstrated favorable anatomy for potential dose sparing of critical structures. Comprehensive MRI illustrations are provided to help radiation oncologists recognize the location, trajectory, and relationship of these structures, facilitating their contouring and ultimately aiding in achieving meaningful dose reductions to these erectile function structures.

OBJECTIVE:To develop a tool for the clinical hybrid imaging workflow which combines morphologic and functional measurements. And to quantify the number of clicks saved per positron emission tomography/computed tomography (PET/CT) interpretation. METHODS:A tool was developed where a volume of interest (VOI) is automatically created around line distance measurements. VOI statistics for both PET and CT component, and line distances are generated and displayed. Usage data for the first two months after introduction of the tool was analyzed. RESULTS:Eleven radiologists and nuclear medicine physicians used the tool in 364 PET/CTs. In 19% of examinations, the novel tool was the only tool that needed to be used. The novel combined tool was used 1001 times, whereas the traditional spherical VOI had been placed 1131 times. The usage ratio of new to traditional tool differed significantly between examinations with ≤ 6 annotations (ratio 1.0) versus > 6 annotations (ratio 0.63, p = 0.030). The average number of saved clicks per PET/CT was estimated at 16.5. CONCLUSION/CONCLUSIONS:A novel combined measurement tool for hybrid imaging was implemented and saved on average 16.5 clicks per examination. These improvements contribute to a smoother workflow and demonstrate the positive impact of thoughtful software design in medical practice.

Prostate-specific membrane antigen (PSMA) PET is a powerful tool for prostate cancer staging and restaging, providing higher sensitivity and specificity than conventional imaging. The recognition of interpretive pitfalls led to the development of various scoring systems and frameworks, which in turn created challenges for consistent interpretation. The Prostate Cancer Molecular Imaging Standardized Evaluation (PROMISE) version 2 classification integrates the five-point PRIMARY score for assessing local disease, the molecular imaging TNM stage for disease extent, and the PSMA expression score to assess eligibility for PSMA-targeted radioligand therapy. The PSMA Reporting and Data System (PSMA-RADS) classifies PSMA PET/CT findings on the basis of the likelihood of presence of prostate cancer. For assessing therapy response, PSMA PET Progression (PPP) criteria focus on new lesions and clinical or biochemical progression, whereas Response Evaluation Criteria in PSMA PET/CT (RECIP 1.0) assess new lesions and changes in total PSMA-positive total tumor volume. The European Association of Nuclear Medicine (EANM) E-PSMA guideline and EANM-Society of Nuclear Medicine and Molecular Imaging procedure guidelines provide standardized reporting recommendations, incorporating elements from existing systems such as PROMISE, PSMA-RADS, and PPP. Nevertheless, such systems can be essential for optimizing prostate cancer management and facilitating communication among imaging professionals, clinicians, and patients. This article outlines these systems and discusses potential strengths and weaknesses.

Various imaging modalities play key roles throughout the different stages of prostate cancer. Each imaging modality has different strengths and weaknesses and various scoring systems or frameworks are used to interpret their findings. Discordances between imaging modalities or interpretation frameworks, and even with clinicopathological findings are not uncommon. Discordances often lead to challenges in the decision-making process, especially with dynamically changing indications for newer imaging modalities. While more research is needed on harmonizing interpretations across different modalities, multidisciplinary team discussion is key to optimizing management of patients with prostate cancer when such discordances are present. In this comprehensive review, we take a deep dive in to these various discordances seen in clinical practice and explore their clinical implications.

PURPOSE/OBJECTIVE:To explore pragmatic approaches integrating MRI and PSMA-PET/CT for evaluating extraprostatic extension (EPE) of prostate cancer (PCa). METHODS:>12). Diagnostic performance was tested with receiver operating characteristic (ROC) curves and compared using DeLong and McNemar tests. RESULTS:>12 among which 87.5% (7/8) were corrected upgraded and had pathological EPE. CONCLUSION/CONCLUSIONS:Several pragmatic approaches were explored for integrating MRI and PSMA-PET/CT to assess EPE in PCa. Combining morphological information from MRI and PSMA expression on PET/CT demonstrated good diagnostic performance and may be a simple pragmatic integrated method that can be used.