Vanishing pelvic mass: Decidualized endometriosis during pregnancy.

A 40-year-old woman without history of endometriosis was found to have 10 cm pelvic mass on the routine first trimester ultrasound. Magnetic resonance imaging (MRI) of the pelvis demonstrated a large solid mass abutting the rectum which raised the concern for malignancy. Transrectal biopsy of the mass was performed with histopathology result of decidualized endometriosis. Patient continued her pregnancy and had cesarean section at 39 weeks. Interestingly, no mass was found when obstetrician performed pelvic examination after delivery in the operative room. This case is a unique presentation of endometriosis during pregnancy in a patient with no prior history of endometriosis. Large size and abutment of the rectum by the decidualized endometriosis on MRI led to misinterpretation as malignancy. Our case highlights complexity of the deep infiltrative endometriosis (DIE) during pregnancy which can misguide the providers, lead to unnecessary procedures and unwanted complications.

Cumulative cancer locations on prostate biopsy and active surveillance outcomes in the MRI era.

BACKGROUND: To validate the use of a cumulative cancer locations (CCLO) score, a measurement of tumor volume on biopsy, and to develop a novel magnetic resonance imaging (MRI)-informed CCLO (mCCLO) score to predict clinical outcomes on active surveillance (AS). METHODS: The CCLO score is a sum of uniquely involved sextants with prostate cancer on diagnostic + confirmatory biopsy. The mCCLO score incorporates MRI findings into the CCLO score. Participants included 1284 individuals enrolled on AS between 1994 and 2022, 343 of whom underwent prostate MRI. The primary outcome was grade reclassification (GR) to grade group ≥2 disease; the secondary outcome was receipt of definitive treatment. RESULTS: Increasing CCLO and mCCLO risk groups were associated with higher risk of GR and undergoing definitive treatment (both p < 0.001). On multivariable analysis, increasing mCCLO score was associated with higher risk of GR and receipt of definitive treatment (hazard ratios [HRs] per 1-unit increase: 1.26 [95% confidence interval [CI]: 1.12-1.41] and 1.21 [95% CI: 1.07-1.36], respectively). The model using mCCLO score to predict GR (c-index: 0.671; 95% CI: 0.621-0.721) performed at least as well as models using the number of cores positive for cancer (0.664 [0.613-0.715]; p = 0.7) and the maximum percentage of cancer in a core (0.641 [0.585-0.696]; p = 0.14). CONCLUSIONS: The CCLO score is a valid, objective metric to predict GR and receipt of treatment in a large AS cohort. The ability of the MRI-informed mCCLO to predict GR is on par with traditional metrics of tumor volume but is more descriptive and may benefit from greater reproducibility. The mCCLO score can be implemented as a shorthand, informative tool for counseling patients about whether to remain on AS.

PRECISE Version 2: Updated Recommendations for Reporting Prostate Magnetic Resonance Imaging in Patients on Active Surveillance for Prostate Cancer.

BACKGROUND AND OBJECTIVE: The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations standardise the reporting of prostate magnetic resonance imaging (MRI) in patients on active surveillance (AS) for prostate cancer. An international consensus group recently updated these recommendations and identified the areas of uncertainty. METHODS: A panel of 38 experts used the formal RAND/UCLA Appropriateness Method consensus methodology. Panellists scored 193 statements using a 1-9 agreement scale, where 9 means full agreement. A summary of agreement, uncertainty, or disagreement (derived from the group median score) and consensus (determined using the Interpercentile Range Adjusted for Symmetry method) was calculated for each statement and presented for discussion before individual rescoring. KEY FINDINGS AND LIMITATIONS: Participants agreed that MRI scans must meet a minimum image quality standard (median 9) or be given a score of 'X' for insufficient quality. The current scan should be compared with both baseline and previous scans (median 9), with the PRECISE score being the maximum from any lesion (median 8). PRECISE 3 (stable MRI) was subdivided into 3-V (visible) and 3-NonV (nonvisible) disease (median 9). Prostate Imaging Reporting and Data System/Likert ≥3 lesions should be measured on T2-weighted imaging, using other sequences to aid in the identification (median 8), and whenever possible, reported pictorially (diagrams, screenshots, or contours; median 9). There was no consensus on how to measure tumour size. More research is needed to determine a significant size increase (median 9). PRECISE 5 was clarified as progression to stage ≥T3a (median 9). CONCLUSIONS AND CLINICAL IMPLICATIONS: The updated PRECISE recommendations reflect expert consensus opinion on minimal standards and reporting criteria for prostate MRI in AS. PATIENT SUMMARY: The Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) recommendations are used in clinical practice and research to guide the interpretation and reporting of magnetic resonance imaging for patients on active surveillance for prostate cancer. An international panel has updated these recommendations, clarified the areas of uncertainty, and highlighted the areas for further research.

Likelihood of sampling prostate cancer at systematic biopsy as a function of gland volume and number of cores.

BACKGROUND: Pre-biopsy multiparametric magnetic resonance imaging (mpMRI) of the prostate is used to conduct targeted prostate biopsy (TB), guided by ultrasound and registered (fused) to the MRI. Systematic biopsy (SB) continues to be used together with TB or in mpMRI-negative patients. There is insufficient evidence on how to use SB to inform clinical decision-making in the mpMRI era. The purpose of this study was to estimate the effect of prostate volume and number of SB cores on sampling clinically significant prostate cancer (csPCa) using a simulation method based on clinical data. METHODS: SBs were simulated using data from 42 patients enrolled in a transrectal ultrasound robot-assisted biopsy trial. Linear mixed models were used to examine the relationship between the number of SB cores and prostate volume on 1) clinically significant cancer detection probability (csCDP) and 2) percent of mpMRI depicted regions of interest (ROIs) sampled with the SB. RESULTS: Median values and interquartile range (IQR) were 47.16 cm3 (35.61-65.57) for prostate volume, 0.57 cm3 (0.39-0.83) for ROI volume, and 4.0 (2-4) for PI-RADS v2.1 scores on MRI. csCDP increased with the increasing number of simulated SB cores and decreased substantially with larger prostate volume. Similarly, the percent of ROIs sampled increased with the increasing number of simulated SB cores and was lower for prostate volumes ≥60 cm3 compared to glands <60 cm3. CONCLUSIONS: The effect of the number of SBs performed on detecting csPCa varies largely with gland volume. The common 12-core SB can achieve adequate cancer detection and sampling of ROIs in smaller glands, but not in larger glands. In addition to TB or in mpMRI-negative patients, the number of SB cores can be adjusted to prostate volume. Performing 12-core SB alone in ≥60 cm3 glands results in inadequate sampling and potential PCa underdiagnosis.

Baseline prostate health index risk category and risk category changes during active surveillance predict grade reclassification.

BACKGROUND: It is not known whether baseline prostate health index (PHI) at the initiation of active surveillance (AS) or repeated PHI testing during AS is of clinical value after confirmatory biopsy in AS men followed with multiparametric magnetic resonance imaging (mpMRI). METHODS: We identified 382 AS patients with no greater than Grade Group 1 (GG1) prostate cancer on diagnostic and confirmatory biopsy, at least one mpMRI and PHI test, of which 241 had at least 2 PHI tests. Grade reclassification (GR) was defined as ≥GG2 on surveillance biopsy. PHI risk categories 1 to 4 were as defined by the manufacturer. Associations between baseline PHI risk category or baseline PSA density (PSAD), change in PHI risk categories over time or PSAD changes over time and GR were evaluated with multivariable Cox proportional hazard regression models adjusted for age, Prostate Imaging-Reporting and Data System score and number of positive cores. RESULTS: Men with baseline PHI scores in the highest risk categories had lower rates of GR-free survival (log-rank P < 0.001), as did those who increased in PHI risk category or remained in a high PHI risk category during surveillance (log-rank P = 0.032). On multivariable regression, baseline PHI risk category was a predictor of GR (risk category 4 [vs. 1] hazard ratio [HR] 2.74, 95% confidence interval [CI] 1.32-5.66, P = 0.002, model C-index 0.764, Akaike Information Criterion [AIC] 797), as were PHI risk category changes over time (risk category 4 [vs. 1] HR 4.20, 95% CI 1.76-10.05, P = 0.002, C-index 0.759, AIC 489). Separate models with baseline PSAD and PSAD changes over time yielded C-indices of 0.709 (AIC 809) and 0.733 (AIC 495) respectively. CONCLUSIONS: Baseline PHI risk category and PHI changes over time were both independent predictors of GR after confirmatory biopsy, but the added benefit over PSAD seemed modest. However, baseline PHI and PHI risk category changes provided clinically useful risk stratification for time to GR, so further evaluation of PHI's ability to help reduce the frequency of mpMRI and/or surveillance biopsies with more PHI data points over time may be warranted.

Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) Magnetic Resonance Imaging Scoring to Predict Clinical Outcomes in Active Surveillance for Grade Group 1 Prostate Cancer.

OBJECTIVE: To determine whether radiological change on serial multiparametric magnetic resonance imaging scored using the Prostate Cancer Radiological Estimation of Change in Sequential Evaluation (PRECISE) Scoring system predicts grade reclassification (GR) at surveillance biopsy in men on active surveillance (AS) with Grade Group 1 (GG1) prostate cancer (PCa). METHODS: We retrospectively reviewed records of 255 men with low-risk PCa on AS with magnetic resonance imaging (MRI)-informed diagnostic and confirmatory biopsies and studied the subset who had surveillance biopsies (n = 163) within 6months of an interval MRI. RESULTS: We studied 309 PRECISE scores in 255 men. 14% demonstrated radiological progression (PRECISE 4-5) on interval MRI performed within 24months, compared to 34% of those whose interval MRI was performed at a >3-year interval (P = .002). 28% (46/163) of men undergoing surveillance biopsy experienced GR to ≥ GG2 PCa. There was no significant increase in the rate of GR with increasing PRECISE score (PRECISE 1-2: 24%, PRECISE 3: 23%, PRECISE 4-5: 38%; P = .11). There was a significant increase in the rate of GR with increasing PI-RADS score (P < .05). On multivariable analysis, a PI-RADS score of 4-5 was significantly associated with GR compared to men who had a highest PI-RADS ≤3 (OR=1.98 [95% CI: 1.45-3.09, P = .01]). CONCLUSION: In a low-risk AS cohort with limited follow-up, a patient's highest PI-RADS rather than their PRECISE score on interval MRI was predictive of GR on surveillance biopsy.

American College of Radiology initiatives on prostate magnetic resonance imaging quality.

Magnetic resonance imaging (MRI) has become integral to diagnosing and managing patients with suspected or confirmed prostate cancer. However, the benefits of utilizing MRI can be hindered by quality issues during imaging acquisition, interpretation, and reporting. As the utilization of prostate MRI continues to increase in clinical practice, the variability in MRI quality and how it can negatively impact patient care have become apparent. The American College of Radiology (ACR) has recognized this challenge and developed several initiatives to address the issue of inconsistent MRI quality and ensure that imaging centers deliver high-quality patient care. These initiatives include the Prostate Imaging Reporting and Data System (PI-RADS), developed in collaboration with an international panel of experts and members of the European Society of Urogenital Radiology (ESUR), the Prostate MR Image Quality Improvement Collaborative, which is part of the ACR Learning Network, the ACR Prostate Cancer MRI Center Designation, and the ACR Appropriateness Criteria. In this article, we will discuss the importance of these initiatives in establishing quality assurance and quality control programs for prostate MRI and how they can improve patient outcomes.

Identifying Men Who Can Remain on Active Surveillance Despite Biopsy Reclassification to Grade Group 2 Prostate Cancer.

PURPOSE: Men on active surveillance with Grade Group 1 prostate cancer who reclassify to Grade Group 2 on surveillance biopsy often leave active surveillance. We aimed to identify subgroups of men who can safely remain on active surveillance despite preoperative reclassification to Grade Group 2. MATERIALS AND METHODS: We studied 249 active surveillance patients with surveillance biopsies classified as Grade Group 1 or Grade Group 2 who underwent radical prostatectomy. Perineural invasion, cancer volume, linear length and maximum percentage of Gleason pattern 4, and prostate-specific antigen density were evaluated. Radical prostatectomy adverse pathology was defined by any of: pN1; ≥pT3; ≥Grade Group 2 with ≥20% Gleason pattern 4; intraductal carcinoma; large cribriform glands. RESULTS: A multivariable logistic regression model incorporating prostate-specific antigen density and perineural invasion stratified radical prostatectomy adverse pathology risk among Grade Group 1 and Grade Group 2 active surveillance patients. 57% (39/68) of Grade Group 1 men reclassified to Grade Group 2 while on active surveillance had favorable radical prostatectomy pathology. Those without biopsy perineural invasion and with low prostate-specific antigen density were more likely to have favorable radical prostatectomy pathology. CONCLUSIONS: Most Grade Group 1 men who enter active surveillance and subsequently reclassify to Grade Group 2 have favorable findings at radical prostatectomy and can remain on active surveillance. Among patients reclassified to Grade Group 2, those with low prostate-specific antigen density and without perineural invasion had the lowest risk of radical prostatectomy adverse pathology, comparable to (or below) that of Grade Group 1 patients who were not reclassified to Grade Group 2 preoperatively. Prostate-specific antigen density and perineural invasion stratify risk in active surveillance patients reclassified to Grade Group 2 and, if concordant with other clinicopathological and radiographic findings, can enable more patients to remain on active surveillance. Reclassification to Grade Group 2 alone should not disqualify men from remaining on active surveillance.

Clinical Significance of Perineural Invasion in Men With Grade Group 1 Prostate Cancer on Active Surveillance.

PURPOSE: We aimed to evaluate the clinical significance of perineural invasion in men on active surveillance for Grade Group 1 prostate cancer. MATERIALS AND METHODS: We identified 1,969 men with Grade Group 1 prostate cancer and at least 1 follow-up biopsy. A time-dependent Cox model and a logistic regression model were used to assess the association between biopsy-detected perineural invasion and grade reclassification (defined as the detection of Grade Group ≥2 prostate cancer on a surveillance biopsy), and adverse pathology (defined as Grade Group ≥3 ± seminal vesicle invasion ± lymph node involvement) at radical prostatectomy, respectively. RESULTS: The 198 men with perineural invasion detected during active surveillance had lower rates of grade reclassification-free survival than those without perineural invasion (P < .001). On multivariable analysis perineural invasion was significantly associated with grade reclassification (HR 3.25, 95% CI 2.54-4.16, P < .001); an association that persisted in the multiparametric magnetic resonance imaging subset. At radical prostatectomy, men with biopsy-detected perineural invasion had more extraprostatic extension than men without perineural invasion (Relative Risk 1.71, 95% CI 1.15-2.56). However, on multivariable analysis biopsy-detected perineural invasion was not associated with adverse pathology (OR 0.68, 95% CI 0.27-1.68, P = .40) and these patients did not exhibit more biochemical recurrence at 5 years (P > .05). CONCLUSIONS: Perineural invasion during active surveillance was associated with grade reclassification. At radical prostatectomy biopsy-detected perineural invasion patients exhibited more extraprostatic extension but biopsy-detected perineural invasion was not independently associated with more adverse pathology. In addition, these patients did not have more biochemical recurrence during follow-up. Perineural invasion should not preclude Grade Group 1 patients from active surveillance but they may warrant more stringent monitoring.

Prostate multi-parametric magnetic resonance imaging appearance of diffuse adenosis of the peripheral zone (DAPZ).

Imaging specialists must recognize potential mimics of prostate cancer (PCa) on multi-parametric magnetic resonance imaging (mpMRI). We describe the appearance of diffuse adenosis of the peripheral zone (DAPZ) on mpMRI. The features of DAPZ parallel those of diffuse PCa, with low signal on T2-weighted images, rapid enhancement on dynamic contrast-enhanced sequences, and restricted diffusion. DAPZ is typically encountered in younger men with elevated prostate specific antigen (PSA) levels and portends an increased risk of the development of PCa. Recognition of the imaging appearance of DAPZ may reassure patients with concordant pathologic findings and may aid in selecting patients for follow-up.

Prostate MRI Qualification: AJR Expert Panel Narrative Review.

Prostate MRI is now established as a first-line investigation for individuals presenting with suspected localized or locally advanced prostate cancer. Successful delivery of the MRI-directed pathway for prostate cancer diagnosis relies on high-quality imaging as well as the interpreting radiologist's experience and expertise. Radiologist certification in prostate MRI may help limit interreader variability, optimize outcomes, and provide individual radiologists with documentation of meeting predefined standards. This AJR Expert Panel Narrative Review summarizes existing certification proposals, recognizing variable progress across regions in establishing prostate MRI certification programs. To our knowledge, Germany is the only country with a prostate MRI certification process that is currently available for radiologists. However, prostate MRI certification programs have also recently been proposed in the United States and United Kingdom and by European professional society consensus panels. Recommended qualification processes entail a multifaceted approach, incorporating components such as minimum case numbers, peer learning, course participation, continuing medical education credits, and feedback from pathology results. Given the diversity in health care systems, including in the provision and availability of MRI services, national organizations will likely need to take independent approaches to certification and accreditation. The relevant professional organizations should begin developing these programs or continue existing plans for implementation.

Tumor Connectomics: Mapping the Intra-Tumoral Complex Interaction Network Using Machine Learning.

The high-level relationships that form complex networks within tumors and between surrounding tissue is challenging and not fully understood. To better understand these tumoral networks, we developed a tumor connectomics framework (TCF) based on graph theory with machine learning to model the complex interactions within and around the tumor microenvironment that are detectable on imaging. The TCF characterization model was tested with independent datasets of breast, brain, and prostate lesions with corresponding validation datasets in breast and brain cancer. The TCF network connections were modeled using graph metrics of centrality, average path length (APL), and clustering from multiparametric MRI with IsoSVM. The Matthews Correlation Coefficient (MCC), Area Under the Curve-ROC, and Precision-Recall (AUC-ROC and AUC-PR) were used for statistical analysis. The TCF classified the breast and brain tumor cohorts with an IsoSVM AUC-PR and MCC of 0.86, 0.63 and 0.85, 0.65, respectively. The TCF benign breast lesions had a significantly higher clustering coefficient and degree centrality than malignant TCFs. Grade 2 brain tumors demonstrated higher connectivity compared to Grade 4 tumors with increased degree centrality and clustering coefficients. Gleason 7 prostate lesions had increased betweenness centrality and APL compared to Gleason 6 lesions with AUC-PR and MCC ranging from 0.90 to 0.99 and 0.73 to 0.87, respectively. These TCF findings were similar in the validation breast and brain datasets. In conclusion, we present a new method for tumor characterization and visualization that results in a better understanding of the global and regional connections within the lesion and surrounding tissue.

Multiparametric magnetic resonance imaging to characterize cabotegravir long-acting formulation depot kinetics in healthy adult volunteers.

AIM: Cabotegravir long-acting (LA) intramuscular (IM) injection is being investigated for HIV preexposure prophylaxis due to its potent antiretroviral activity and infrequent dosing requirement. A subset of healthy adult volunteers participating in a Phase I study assessing cabotegravir tissue pharmacokinetics underwent serial magnetic resonance imaging (MRI) to assess drug depot localization and kinetics following a single cabotegravir LA IM targeted injection. METHODS: Eight participants (four men, four women) were administered cabotegravir LA 600 mg under ultrasonographic-guided injection targeting the gluteal muscles. MRI was performed to determine injection-site location in gluteal muscle (IM), subcutaneous (SC) adipose tissue and combined IM/SC compartments, and to quantify drug depot characteristics, including volume and surface area, on Days 1 (≤2 hours postinjection), 3 and 8. Linear regression analysis examined correlations between MRI-derived parameters and plasma cabotegravir exposure metrics, including maximum observed concentration (Cmax ) and partial area under the concentration-time curve (AUC) through Weeks 4 and 8. RESULTS: Cabotegravir LA depot locations varied by participant and were identified in the IM compartment (n = 2), combined IM/SC compartments (n = 4), SC compartment (n = 1) and retroperitoneal cavity (n = 1). Although several MRI parameter and exposure metric correlations were determined, total depot surface area on Day 1 strongly correlated with plasma cabotegravir concentration at Days 3 and 8, Cmax and partial AUC through Weeks 4 and 8. CONCLUSION: MRI clearly delineated cabotegravir LA injection-site location and depot kinetics in healthy adults. Although injection-site variability was observed, drug depot surface area correlated with both plasma Cmax and partial AUC independently of anatomical distribution.

Prostate Magnetic Resonance Imaging for Local Recurrence Reporting (PI-RR): International Consensus -based Guidelines on Multiparametric Magnetic Resonance Imaging for Prostate Cancer Recurrence after Radiation Therapy and Radical Prostatectomy.

BACKGROUND: Imaging techniques are used to identify local recurrence of prostate cancer (PCa) for salvage therapy and to exclude metastases that should be addressed with systemic therapy. For magnetic resonance imaging (MRI), a reduction in the variability of acquisition, interpretation, and reporting is required to detect local PCa recurrence in men with biochemical relapse after local treatment with curative intent. OBJECTIVE: To propose a standardised method for image acquisition and assessment of PCa local recurrence using MRI after radiation therapy (RP) and radical prostatectomy (RT). EVIDENCE ACQUISITION: Prostate Imaging for Recurrence Reporting (PI-RR) was formulated using the existing literature. An international panel of experts conducted a nonsystematic review of the literature. The PI-RR system was created via consensus through a combination of face-to-face and online discussions. EVIDENCE SYNTHESIS: Similar to with PI-RADS, based on the best available evidence and expert opinion, the minimum acceptable MRI parameters for detection of recurrence after radiation therapy and radical prostatectomy are set. Also, a simplified and standardised terminology and content of the reports that use five assessment categories to summarise the suspicion of local recurrence (PI-RR) are designed. PI-RR scores of 1 and 2 are assigned to lesions with a very low and low likelihood of recurrence, respectively. PI-RR 3 is assigned if the presence of recurrence is uncertain. PI-RR 4 and 5 are assigned for a high and very high likelihood of recurrence, respectively. PI-RR is intended to be used in routine clinical practice and to facilitate data collection and outcome monitoring for research. CONCLUSIONS: This paper provides a structured reporting system (PI-RR) for MRI evaluation of local recurrence of PCa after RT and RP. PATIENT SUMMARY: A new method called PI-RR was developed to promote standardisation and reduce variations in the acquisition, interpretation, and reporting of magnetic resonance imaging for evaluating local recurrence of prostate cancer and guiding therapy.

Transperineal Prostate Biopsy Improves the Detection of Clinically Significant Prostate Cancer among Men on Active Surveillance.

PURPOSE: Transperineal prostate biopsy offers improved sampling of the anterior prostate compared to the transrectal approach. The objective of this study was to determine if transperineal prostate biopsy is associated with an increased incidence of cancer upgrading among men on active surveillance for very low or low risk prostate cancer. MATERIALS AND METHODS: Our active surveillance registry was queried to identify patients who underwent a surveillance biopsy following the introduction of transperineal prostate biopsy at our institution. Patients were dichotomized by the type of biopsy performed. The baseline characteristics and rates of cancer upgrading were compared between groups. RESULTS: Between November 2017 and June 2020, 790 men with very low or low risk prostate cancer underwent a surveillance biopsy. In total, 59 of 279 men (21.2%) in the transperineal prostate biopsy group were upgraded to grade group ≥2 as compared to 75 of 511 (14.7%) in the transrectal biopsy group (p=0.01). Among patients who were upgraded to grade group ≥2, 26 of 59 (44%) had grade group ≥2 detected in the anterior/transition zone with transperineal prostate biopsy compared to 14 of 75 (18.7%) with transrectal biopsy (p=0.01). Additionally, 17 of 279 men (6.1%) who underwent transperineal prostate biopsy were upgraded to grade group ≥3 vs 17 of 511 (3.3%) who underwent transrectal biopsy (p=0.05). After adjusting for age, prostate specific antigen density, use of magnetic resonance imaging, and number of prior transrectal biopsies, transperineal prostate biopsy was significantly associated with upgrading to grade group ≥2 (OR 1.49, 95% CI 1.11-2.19, p=0.01). CONCLUSIONS: Among men on active surveillance for very low or low risk prostate cancer, transperineal prostate biopsy was associated with an increased likelihood of upgrading to clinically significant prostate cancer. This is likely due to improved sampling of the anterior prostate with the transperineal approach.

Magnetic Resonance Imaging-Guided Transurethral Ultrasound Ablation of Prostate Cancer.

PURPOSE: Magnetic resonance imaging-guided transurethral ultrasound ablation uses directional thermal ultrasound under magnetic resonance imaging thermometry feedback control for prostatic ablation. We report 12-month outcomes from a prospective multicenter trial (TACT). MATERIALS AND METHODS: A total of 115 men with favorable to intermediate risk prostate cancer across 13 centers were treated with whole gland ablation sparing the urethra and apical sphincter. The co-primary 12-month endpoints were safety and efficacy. RESULTS: In all, 72 (63%) had grade group 2 and 77 (67%) had NCCN® intermediate risk disease. Median treatment delivery time was 51 minutes with 98% (IQR 95-99) thermal coverage of target volume and spatial ablation precision of ±1.4 mm on magnetic resonance imaging thermometry. Grade 3 adverse events occurred in 9 (8%) men. The primary endpoint (U.S. Food and Drug Administration mandated) of prostate specific antigen reduction ≥75% was achieved in 110 of 115 (96%) with median prostate specific antigen reduction of 95% and nadir of 0.34 ng/ml. Median prostate volume decreased from 37 to 3 cc. Among 68 men with pretreatment grade group 2 disease, 52 (79%) were free of grade group 2 disease on 12-month biopsy. Of 111 men with 12-month biopsy data, 72 (65%) had no evidence of cancer. Erections (International Index of Erectile Function question 2 score 2 or greater) were maintained/regained in 69 of 92 (75%). Multivariate predictors of persistent grade group 2 at 12 months included intraprostatic calcifications at screening, suboptimal magnetic resonance imaging thermal coverage of target volume and a PI-RADS™ 3 or greater lesion at 12-month magnetic resonance imaging (p <0.05). CONCLUSIONS: The TACT study of magnetic resonance imaging-guided transurethral ultrasound whole gland ablation in men with localized prostate cancer demonstrated effective tissue ablation and prostate specific antigen reduction with low rates of toxicity and residual disease.

PI-RADS Committee Position on MRI Without Contrast Medium in Biopsy-Naive Men With Suspected Prostate Cancer: Narrative Review.

The steadily increasing demand for diagnostic prostate MRI has led to concerns regarding the lack of access to and the availability of qualified MRI scanners and sufficiently experienced radiologists, radiographers, and technologists to meet the demand. Solutions must enhance operational benefits without compromising diagnostic performance, quality, and delivery of service. Solutions should also mitigate risks such as decreased reader confidence and referrer engagement. One approach may be the implementation of MRI without the use gadolinium-based contrast medium (bipara-metric MRI), but only if certain prerequisites such as high-quality imaging, expert interpretation quality, and availability of patient recall or on-table monitoring are mandated. Alternatively, or in combination, a clinical risk-based approach could be used for protocol selection, specifically, which biopsy-naive men need MRI with contrast medium (multiparametric MRI). There is a need for prospective studies in which biopsy decisions are made according to MRI without contrast enhancement. Such studies must define clinical and operational benefits and identify which patient groups can be scanned successfully without contrast enhancement. These higher-quality data are needed before the Prostate Imaging Reporting and Data System (PI-RADS) Committee can make evidence-based recommendations about MRI without contrast enhancement as an initial diagnostic approach for prostate cancer workup.

RadioGraphics Update: PI-RADS Version 2.1-A Pictorial Update.

Editor's Note.-Articles in the RadioGraphics Update section provide current knowledge to supplement or update information found in full-length articles previously published in RadioGraphics. Authors of the previously published article provide a brief synopsis that emphasizes important new information such as technological advances, revised imaging protocols, new clinical guidelines involving imaging, or updated classification schemes. Articles in this section are published solely online and are linked to the original article.