Faculty Bibliography

OBJECTIVES/OBJECTIVE:Prostate-specific membrane antigen (PSMA)-PET/CT has become integral to management of prostate cancer; however, PSMA-avid rib lesions pose a diagnostic challenge. This study investigated clinicopathological and imaging findings that predict metastatic etiology of PSMA-avid rib lesions. MATERIALS AND METHODS/METHODS:), miPSMA score), CT features (sclerotic, lucent, fracture, no correlate), other sites of metastases, and primary tumor findings. A composite reference standard for rib lesion etiology (metastatic vs non-metastatic) based on histopathology, serial imaging, and clinical assessment was used. RESULTS:, miPSMA), more commonly involved multiple ribs, and were more often sclerotic (p < 0.01); lucency/fractures were only seen in benign lesions. CONCLUSION/CONCLUSIONS:Several imaging and clinicopathological factors differed between PSMA-avid metastatic and benign lesions. Isolated rib lesions without other sites of metastasis are almost always benign. Careful assessment of CT features can help diagnose benign lesions. KEY POINTS/CONCLUSIONS:Question While prostate-specific membrane antigen (PSMA)-PET/CT has become integral to the management of prostate cancer, PSMA-avid rib lesions pose a diagnostic challenge. Findings Approximately a quarter of patients who had PSMA-avid rib lesions were metastatic. However, only 2.1% of them had isolated rib metastasis (without PSMA-avid metastases elsewhere). Clinical relevance Isolated PSMA-avid rib lesions are almost always benign when there is no evidence of metastatic disease elsewhere. Scrutinizing CT features can help diagnose benign PSMA-avid lesions with greater certainty.

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.

BACKGROUND:Potential rural-urban differences in prostate cancer care are understudied, particularly regarding the utilization of advanced diagnostic tests. Herein we examined variations in Positron Emission Tomography (PET) utilization for prostate cancer care, including diagnosis, staging and treatment planning, across residential regions in the United States. METHODS:Patients newly diagnosed with prostate cancer between 2019 and 2021 and post-diagnostic PETs were identified using full Medicare claims data. PET use was assessed in all newly diagnosed patients, though indications vary by risk. Patients' counties were categorized as metro, urban, or rural, from most to least urbanized. Regional PET utilization was further examined at the level of hospital referral regions. A multivariable logistic regression model was performed to assess the impact of rurality on PET imaging. A secondary analysis included an interaction term for race to explore the effect of residence on PET imaging by racial group. RESULTS:Overall, 495 865 patients were included in the analysis: 393 861 (79.4%) lived in metro, 56 698 (11.4%) in urban and 39 707 (8.0%) in rural counties. Patients in metro counties underwent PET imaging more often (8.4%) than patients in urban (7.3%) or rural counties (7.2%), p < 0.0001. At a level of hospital referral region, PET utilization rates ranged from 2.2 to 20.8%. PET imaging was more commonly performed in White compared to Black or Hispanic patients. Rural patients were less likely to undergo PET imaging compared to metro patients (odds ratio [OR] 0.87, 95% Confidence interval [CI]: 0.82-0.92 p < 0.0001). Rural Black (OR 0.69, 95%CI 0.57-0.83, p < 0.0001) and rural White patients (OR 0.89, 95%CI 0.83-0.94 p < 0.0001) were less likely to obtain PET imaging compared to their metro counterparts, p-interaction < 0.0001. CONCLUSION/CONCLUSIONS:Rural patients were less likely to undergo PET imaging than metro patients. The effect of rurality was most pronounced among Black patients. Our findings underscore the need for strategies to support equitable use of PET imaging.

OBJECTIVES/OBJECTIVE:An increasing number of patients with prostate cancer (PCa) undergo assessment with magnetic resonance imaging (MRI) and prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA-PET/CT). This offers comprehensive multimodality staging but can lead to discrepancies. The objective was to assess the rates and types of discordance between MRI and PSMA-PET/CT for primary PCa assessment. MATERIALS AND METHODS/METHODS:Consecutive men diagnosed with intermediate and high-risk PCa who underwent MRI and PSMA-PET/CT in 2021-2023 were retrospectively included. MRI and PSMA-PET/CT were interpreted using PI-RADS v2.1 and PRIMARY scores. Discordances between the two imaging modalities were categorized as "minor" (larger or additional lesion seen on one modality) or "major" (positive on only one modality or different index lesions between MRI and PSMA-PET/CT) and reconciled using radical prostatectomy or biopsy specimens. RESULTS:Three hundred and nine men (median age 69 years, interquartile range (IQR) 64-75) were included. Most had Gleason Grade Group ≥ 3 PCa (70.9% (219/309)). Median PSA was 9.0 ng/mL (IQR 5.6-13.6). MRI and PSMA-PET/CT were concordant in 157/309 (50.8%) and discordant in 152/309 (49.1%) patients; with 39/152 (25.7%) major and 113/152 (74.3%) minor discordances. Of 27 patients with lesions only seen on MRI, 85.2% (23/27) were clinically significant PCa (csPCa). Of 23 patients with lesions only seen on PSMA-PET/CT, 78.3% (18/23) were csPCa. Altogether, lesions seen on only one modality were csPCa in 80.0% (36/45). CONCLUSION/CONCLUSIONS:MRI and PSMA-PET/CT were discordant in half of patients for primary PCa evaluation, with major discrepancies seen in roughly one out of eight patients. KEY POINTS/CONCLUSIONS:Question While both MRI and PSMA-PET/CT can be used for primary tumor assessment, the discordances between them are not well established. Findings MRI and PSMA-PET/CT were discordant in about half of the patients. Most prostate lesions seen on only one modality were significant cancer. Clinical relevance MRI and PSMA-PET/CT are often discordant for assessing the primary prostate tumor. Using both modalities for primary prostate tumor evaluation can provide complementary information that may substantially impact treatment planning.

Liquid biopsy helps detect cells and cell-derived metabolites, proteins, nucleic acids, and vesicles that are shed into body fluids by tumors. This diagnostic test requires only approximately 10 mL of blood or urine. It has received considerable attention as a minimally invasive tool for whole-body tumor interrogation for use in patients with cancer. It poses an attractive and potentially cost-effective alternative to invasive tissue sampling through tissue biopsies, especially serial assessments, such as for treatment response evaluation and mutations that occur during cancer treatment. Cell-free and circulating tumor DNA are the most frequently tested liquid biopsy analytes, and have shown promise for cancer screening, assessment of residual disease after treatment, and clinical outcome prediction and prognostication. Whereas liquid biopsy is less sensitive than imaging in early tumor stages, it is more specific and may help detect treatment response earlier than the Response Evaluation Criteria in Solid Tumors, or RECIST. Aimed primarily at radiologists, this review article provides an update on recent developments in the use of liquid biopsy, including findings from landmark clinical trials and U.S. regulatory approvals as companion diagnostic tests for clinical use, particularly in four malignancies: lymphoma, breast cancer, prostate cancer, and melanoma. Finally, current challenges for the clinical implementation of liquid biopsy are discussed.

Multiparametric MRI of the bladder is highly accurate in the detection and local staging of bladder cancer. The Vesical Imaging Reporting and Data System (VI-RADS) scoring system has improved the diagnostic accuracy, reproducibility, and interpretability of bladder MRI in the assessment of the invasion of the muscularis propria. There are several technical details concerning bladder MRI that need to be strictly applied to obtain the highest possible diagnostic potential from the MRI. In addition, image evaluation, accurate interpretation, and reporting need to be standardized to optimize diagnostic accuracy and interreader agreement. This review describes the patient population for bladder MRI and discusses, with a practical approach, the correct acquisition protocol for optimal image quality using VI-RADS with reporting tips, pitfalls, and challenges for its clinical application. This review also discusses the latest evidence, clinical implications, current controversies, and future challenges, including gaps in knowledge, of the VI-RADS scoring system.

OBJECTIVES/UNASSIGNED:To evaluate the incidence and degree of rectal wall infiltration (RWI) of spacer gel used during prostate radiotherapy among two practitioners experienced in using rectal spacers. MATERIALS AND METHODS/UNASSIGNED:Consecutive patients with prostate cancer who received prostate radiotherapy after hydrogel rectal spacer insertion in August 2023-August 2024 by two experienced practitioners were retrospectively included. Post-implant magnetic resonance imaging examinations were evaluated by two radiologists for RWI: 0 (no abnormality), 1 (rectal wall edema), 2 (superficial RWI), and 3 (deep RWI). Scores 2-3 were considered positive for RWI and their location and degree of RWI (radial, longitudinal, and circumferential) were also categorized. Inter-reader agreement was assessed with Cohen's Kappa. RESULTS/UNASSIGNED:215 men were included. Agreement was substantial between the radiologists for RWI scores (Kappa, 0.697; 95% confidence interval, 0.594-0.800). RWI scores were 0 in 80.5% (173/215), 1 in 7.9% (17/215), 2 in 10.7% (23/215), and, 3 in 0.9% (2/215) of the men. Altogether, RWI was present (scores 2-3) in 11.6% (25/215), most commonly in the mid-gland and apex with median radial, longitudinal, and circumferential involvement of 3.2 mm, 8.6 mm, and 11.5%. None of these patients demonstrated any significant rectal toxicity. CONCLUSION/UNASSIGNED:RWI was very uncommon for experienced practitioners. The degree of RWI was focal and not associated with increased complications.

The American College of Radiology Vesical Imaging-Reporting and Data System (VI-RADS) Steering Committee will strive to ensure high-quality imaging practices for bladder cancer (BC) and improve outcomes for BC patients. Work will involve evaluation of the current status of magnetic resonance imaging for BC and identify actionable areas to improve its utility in clinical practice. Current VI-RADS gaps related to unmet clinical needs, research areas to address, and future steps and timelines will be identified.