Prototype Description and Ex Vivo Evaluation of a System for Combined Endorectal Magnetic Resonance Imaging and In-Bore Biopsy of the Prostate.

ABSTRACT: We describe early ex vivo proof-of-concept testing of a novel system composed of a disposable endorectal coil and converging multichannel needle guide with a reusable clamp stand, embedded electronics, and baseplate to allow for endorectal magnetic resonance (MR) imaging and in-bore MRI-targeted biopsy of the prostate as a single integrated procedure. Using prostate phantoms imaged with standard T 2 -weighted sequences in a Siemens 3T Prisma MR scanner, we measured the signal-to-noise ratio in successive 1-cm distances from the novel coil and from a commercially available inflatable balloon coil and measured the lateral and longitudinal deviation of the tip of a deployed MR compatible needle from the intended target point. Signal-to-noise ratio obtained with the novel system was significantly better than the inflatable balloon coil at each of five 1-cm intervals, with a mean improvement of 78% ( P < 0.05). In a representative sampling of 15 guidance channels, the mean lateral deviation for MR imaging-guided needle positioning was 1.7 mm and the mean longitudinal deviation was 2.0 mm. Our ex vivo results suggest that our novel system provides significantly improved signal-to-noise ratio when compared with an inflatable balloon coil and is capable of accurate MRI-guided needle deployment.

Multimodality Imaging of Cholecystectomy Complications.

Cholecystectomy is one of the most common surgeries performed in the United States. Although complications are uncommon, the high incidence of this surgery means that a radiologist will likely encounter these complications in practice. Complications may arise in the immediate postoperative period or can be delayed for weeks, months, or years after surgery. Vague and nonspecific symptoms make clinical diagnosis challenging. As a result, multimodality imaging is important in postoperative evaluation. US and multidetector CT are the usual first-line imaging modalities. Hepatobiliary scintigraphy, SPECT/CT, and MRI with conventional or gadoxetate hepatobiliary contrast material are important and complementary modalities that are used for workup. The authors begin with a brief discussion of surgical technique and expected postoperative findings and then describe complications organized into four groups: (a) biliary complications, (b) stone-related complications, (c) iatrogenic complications, and (d) gallbladder complications. Biliary complications include bile leaks and bilomas, acute biliary obstruction, and biliary stricture. Stone-related complications include retained and recurrent stones and spillage of stones into the peritoneum. Iatrogenic complications include hemorrhage, vasculobiliary injury, arterial pseudoaneurysms, duodenal injury, and migration of clips. Gallbladder complications include recurrent cholecystitis after subtotal reconstituting cholecystectomy and unexpected gallbladder cancer. An invited commentary by Mullens and Ibrahim is available online. Online supplemental material is available for this article. ©RSNA, 2022.

In-Bore Versus Fusion MRI-Targeted Biopsy of PI-RADS Category 4 and 5 Lesions: A Retrospective Comparative Analysis Using Propensity Score Weighting.

BACKGROUND. Few published studies have compared in-bore and fusion MRI-targeted prostate biopsy, and the available studies have had conflicting results. OBJECTIVE. The purpose of this study was to compare the target-specific cancer detection rate of in-bore prostate biopsy with that of fusion MRI-targeted biopsy. METHODS. The records of men who underwent in-bore or fusion MRI-targeted biopsy of PI-RADS category 4 or 5 lesions between August 2013 and September 2019 were retrospectively identified. PI-RADS version 2.1 assessment category, size, and location of each target were established by retrospective review by a single experienced radiologist. Patient history and target biopsy results were obtained by electronic medical record review. Only the first MRI-targeted biopsy of the dominant lesion was included for patients with repeated biopsies or multiple targets. In-bore and fusion biopsy were compared by propensity score weights and multivariable regression to adjust for imbalances in patient and target characteristics between biopsy techniques. The primary endpoint was target-specific prostate cancer detection rate. Secondary endpoints were detection rate after application of propensity score weighting for cancers in International Society of Urological Pathology (ISUP) grade group 2 (GG2) or higher and detection rate with the use of off-target systematic sampling results. RESULTS. The study sample included 286 men (in-bore biopsy, 191; fusion biopsy, 95). Compared with fusion biopsy, in-bore biopsy was associated with significantly greater likelihood of detection of any cancer (odds ratio, 2.28 [95% CI, 1.04-4.98]; p = .04) and nonsignificantly greater likelihood of detection of ISUP GG2 or higher cancer (odds ratio, 1.57 [95% CI, 0.88-2.79]; p = .12) in a target. When off-target sampling was included, in-bore biopsy and combined fusion and systematic biopsy were not different for detection of any cancer (odds ratio, 1.16 [95% CI, 0.54-2.45]; p = .71) or ISUP GG2 and higher cancer (odds ratio, 1.15 [95% CI, 0.66-2.01]; p = .62). CONCLUSION. In this retrospective study in which propensity score weighting was used, in-bore MRI-targeted prostate biopsy had a higher target-specific cancer detection rate than did fusion biopsy. CLINICAL IMPACT. Pending a larger prospective randomized multicenter comparison between in-bore and fusion biopsy, in-bore may be the preferred approach should performing only biopsy of a suspicious target, without concurrent systematic biopsy, be considered clinically appropriate.

Adenomyosis in Pregnancy: Diagnostic Pearls and Pitfalls.

Adenomyosis is a common benign uterine disorder in which ectopic endometrial glands extend into the myometrium. Adenomyosis is increasingly diagnosed in young women, affecting 20%-35% of women of reproductive age. Features of adenomyosis can be seen with either US or MRI, especially with newer imaging technology. With advances in reproductive endocrinology as well as a trend toward later maternal age, adenomyosis is increasingly noted during pregnancy, often while performing imaging for other reasons. Hormonal changes during pregnancy alter the appearance of adenomyosis, which includes diffuse, focal, and cystic adenomyosis. Recognizing these imaging changes in pregnancy proves essential for accurately diagnosing adenomyosis as a benign condition, as it mimics serious placental and myometrial abnormalities. Using a lower-frequency US transducer or MRI can be helpful in distinguishing among these entities. Describing the location of adenomyosis in relationship to the site of placentation is also important. Diagnosing adenomyosis is crucial because it can be associated with poor pregnancy outcomes, including spontaneous abortion, preterm birth, and fetal growth restriction. Adenomyosis is also a risk factor for preeclampsia. Intramural ectopic pregnancy is a rare but serious condition that can mimic cystic adenomyosis, and comparison with prepregnancy images can help differentiate the two conditions. The authors review the unique imaging characteristics of adenomyosis in pregnancy, focusing on accurate diagnosis of an underrecognized benign condition that can mimic myometrial and placental pathologic conditions.©RSNA, 2021.

Variability of the Positive Predictive Value of PI-RADS for Prostate MRI across 26 Centers: Experience of the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel.

Background Prostate MRI is used widely in clinical care for guiding tissue sampling, active surveillance, and staging. The Prostate Imaging Reporting and Data System (PI-RADS) helps provide a standardized probabilistic approach for identifying clinically significant prostate cancer. Despite widespread use, the variability in performance of prostate MRI across practices remains unknown. Purpose To estimate the positive predictive value (PPV) of PI-RADS for the detection of high-grade prostate cancer across imaging centers. Materials and Methods This retrospective cross-sectional study was compliant with the HIPAA. Twenty-six centers with members in the Society of Abdominal Radiology Prostate Cancer Disease-focused Panel submitted data from men with suspected or biopsy-proven untreated prostate cancer. MRI scans were obtained between January 2015 and April 2018. This was followed with targeted biopsy. Only men with at least one MRI lesion assigned a PI-RADS score of 2-5 were included. Outcome was prostate cancer with Gleason score (GS) greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2). A mixed-model logistic regression with institution and individuals as random effects was used to estimate overall PPVs. The variability of observed PPV of PI-RADS across imaging centers was described by using the median and interquartile range. Results The authors evaluated 3449 men (mean age, 65 years ± 8 [standard deviation]) with 5082 lesions. Biopsy results showed 1698 cancers with GS greater than or equal to 3+4 (International Society of Urological Pathology grade group ≥2) in 2082 men. Across all centers, the estimated PPV was 35% (95% confidence interval [CI]: 27%, 43%) for a PI-RADS score greater than or equal to 3 and 49% (95% CI: 40%, 58%) for a PI-RADS score greater than or equal to 4. The interquartile ranges of PPV at these same PI-RADS score thresholds were 27%-44% and 27%-48%, respectively. Conclusion The positive predictive value of the Prostate Imaging and Reporting Data System was low and varied widely across centers. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Milot in this issue.

Impact of Direct MRI-Guided Biopsy of the Prostate on Clinical Management.

OBJECTIVE. The purpose of this study is to investigate the impact of direct MRI-guided biopsy of the prostate on clinical management in practice. MATERIALS AND METHODS. We retrospectively identified 127 patients with unknown (n = 98) or untreated prostate cancer with a Gleason score of 6 (n = 29) who underwent direct MRI-guided biopsy of the prostate at our institution between August 2013 and January 2018, after initial multiparametric endorectal MRI examination revealed one or more Prostate Imaging Reporting and Data System (PI-RADS or PI-RADSv2) category 4 or 5 target lesion. All available medical and imaging records were reviewed to determine pertinent clinical details, biopsy findings, and postbiopsy management. RESULTS. The mean patient age was 68 years (interquartile range, 63-73 years). Findings from MRI-guided biopsy were positive for 93 of 127 patients (73%), with prostate cancer of Gleason score of 7 or higher diagnosed in 84 of these 93 patients (90%). When stratified by clinical scenario, the rate of positive biopsy findings was 66% (57/86) for patients who had negative findings from one or more prior transrectal ultrasound-guided biopsies, 83% (10/12) for biopsy-naive patients, and 90% (26/29) for patients undergoing active surveillance. Overall, 90 of 127 patients (71%) received a new (n = 67) or upgraded (n = 23) diagnosis of prostate cancer, and 57 of these 90 patients (63%) proceeded to receive treatment with prostatectomy, radiation, or androgen deprivation therapy. CONCLUSION. The results of this study suggest that direct MRI-guided biopsy is associated with high rates of significant prostate cancer detection and subsequent definitive treatment across common clinical scenarios and should be considered an important supplementary diagnostic tool in the appropriate setting.

Endoscopic Interventions in Acute Pancreatitis: What the Advanced Endoscopist Wants to Know.

Endoscopic interventions play an important role in the modern management of pancreatic fluid collections. Successful management of pancreatitis is dependent on proper classification of the disease and its local complications. The 2012 revised Atlanta classification divides acute pancreatitis into subtypes of necrotizing pancreatitis and interstitial edematous pancreatitis (IEP) on the basis of the radiologic presence or absence of necrosis, respectively. Local complications of IEP include acute pancreatic fluid collections and pseudocysts, which contain fluid only and are differentiated by the time elapsed since the onset of symptoms. Local complications of necrotizing pancreatitis include acute necrotic collections and walled-off necrosis, which contain nonliquefied necrotic debris and are differentiated by the time elapsed since the onset of symptoms. Endoscopic techniques are used to treat local complications of pancreatitis, often in a step-up approach, by which less invasive techniques are preferred initially with potential subsequent use of more invasive procedures, dependent on the patient's clinical response and collection evolution. Common interventions performed by the advanced endoscopist include endoscopic transmural drainage and endoscopic transmural necrosectomy. However, some collections require a multimodal approach with adjunctive placement of percutaneous drainage catheters or the use of videoscopic-assisted retroperitoneal débridement. Additional endoscopic interventions may be required in the setting of pancreatic or biliary duct stones or strictures. Common complications of endoscopic intervention in the setting of pancreatitis include bleeding, infection, perforation, and stent migration. This article reviews the classification of acute pancreatitis, familiarizes radiologists with the common endoscopic techniques used in its management, and improves identification of the clinically relevant imaging findings and procedural complications related to endoscopic interventions in pancreatitis. ©RSNA, 2018.

Nongynecologic Findings Seen at Pelvic US.

Ultrasonography (US) is frequently the first imaging modality used to examine women with symptoms involving the pelvis. It is widely available and involves no exposure to ionizing radiation. Images can be acquired with a transabdominal, endovaginal, or translabial approach, and the use of video clips and three-dimensional reconstructions can be helpful. US is excellent for assessment of the uterus, ovaries, and adnexa. Occasionally, nongynecologic pelvic diseases arising from the gastrointestinal, genitourinary, and musculoskeletal systems and the pelvic peritoneal and extraperitoneal spaces may be detected and can be a source of diagnostic dilemma. US can be helpful not only in the detection but also occasionally in the characterization of such entities. Computed tomography and magnetic resonance imaging are useful in complicated cases. In this article, the normal US appearance of the bowel and US signs of bowel disease and specific entities, including appendicitis, diverticular disease, bowel obstruction, appendiceal mucocele, and intestinal tumors, are reviewed. The lower urinary tract is included in the field of view in every pelvic US examination; commonly encountered entities related to the urinary bladder, distal ureter, and urethra are illustrated. In addition to arising in the gastrointestinal and genitourinary tracts, pathologic conditions in the pelvis can arise in the peritoneal or extraperitoneal space. Although conditions of the pelvic peritoneal and extraperitoneal spaces are rare, it is important to recognize these entities and distinguish them from the more common gynecologic diseases. Owing to the implications for diagnosis and management, radiologists and other physicians who perform pelvic US should be aware of the spectrum of nongynecologic pathologic entities that can be detected. ©RSNA, 2017.

Gestational Trophoblastic Disease: Clinical and Imaging Features.

Gestational trophoblastic disease (GTD) is a spectrum of both benign and malignant gestational tumors, including hydatidiform mole (complete and partial), invasive mole, choriocarcinoma, placental site trophoblastic tumor, and epithelioid trophoblastic tumor. The latter four entities are referred to as gestational trophoblastic neoplasia (GTN). These conditions are aggressive with a propensity to widely metastasize. GTN can result in significant morbidity and mortality if left untreated. Early diagnosis of GTD is essential for prompt and successful management while preserving fertility. Initial diagnosis of GTD is based on a multifactorial approach consisting of clinical features, serial quantitative human chorionic gonadotropin (ß-hCG) titers, and imaging findings. Ultrasonography (US) is the modality of choice for initial diagnosis of complete hydatidiform mole and can provide an invaluable means of local surveillance after treatment. The performance of US in diagnosing all molar pregnancies is surprisingly poor, predominantly due to the difficulty in differentiating partial hydatidiform mole from nonmolar abortion and retained products of conception. While GTN after a molar pregnancy is usually diagnosed with serial ß-hCG titers, imaging plays an important role in evaluation of local extent of disease and systemic surveillance. Imaging also plays a crucial role in detection and management of complications, such as uterine and pulmonary arteriovenous fistulas. Familiarity with the pathogenesis, classification, imaging features, and treatment of these tumors can aid in radiologic diagnosis and guide appropriate management. ©RSNA, 2017.

Performance characteristics of magnetic resonance imaging without contrast agents or sedation in pediatric appendicitis.

BACKGROUND: Magnetic resonance imaging (MRI) has emerged as a promising modality for evaluating pediatric appendicitis. However optimal imaging protocols, including roles of contrast agents and sedation, have not been established and diagnostic criteria have not been fully evaluated. OBJECTIVE: To investigate performance characteristics of rapid MRI without contrast agents or sedation in the diagnosis of pediatric appendicitis. MATERIALS AND METHODS: We included patients ages 4-18 years with suspicion of appendicitis who underwent rapid MRI between October 2013 and March 2015 without contrast agent or sedation. After two-radiologist review, we determined performance characteristics of individual diagnostic criteria and aggregate diagnostic criteria by comparing MRI results to clinical outcomes. We used receiver operating characteristic (ROC) curves to determine cut-points for appendiceal diameter and wall thickness for optimization of predictive power, and we calculated area under the curve (AUC) as a measure of test accuracy. RESULTS: Ninety-eight MRI examinations were performed in 97 subjects. Overall, MRI had a 94% sensitivity, 95% specificity, 91% positive predictive value and 97% negative predictive value. Optimal cut-points for appendiceal diameter and wall thickness were ≥7 mm and ≥2 mm, respectively. Independently, those cut-points produced sensitivities of 91% and 84% and specificities of 84% and 43%. Presence of intraluminal fluid (30/33) or localized periappendiceal fluid (32/33) showed a significant association with acute appendicitis (P<0.01), with sensitivities of 91% and 97% and specificities of 60% and 50%. For examinations in which the appendix was not identified by one or both reviewers (23/98), the clinical outcome was negative. CONCLUSION: Rapid MRI without contrast agents or sedation is accurate for diagnosis of pediatric appendicitis when multiple diagnostic criteria are considered in aggregate. Individual diagnostic criteria including optimized cut-points of ≥7 mm for diameter and ≥2 mm for wall thickness demonstrate high sensitivities but relatively low specificities. Nonvisualization of the appendix favors a negative diagnosis.

Revised Atlanta Classification for Acute Pancreatitis: A Pictorial Essay.

The 2012 revised Atlanta classification is an update of the original 1992 Atlanta classification, a standardized clinical and radiologic nomenclature for acute pancreatitis and associated complications based on research advances made over the past 2 decades. Acute pancreatitis is now divided into two distinct subtypes, necrotizing pancreatitis and interstitial edematous pancreatitis (IEP), based on the presence or absence of necrosis, respectively. The revised classification system also updates confusing and sometimes inaccurate terminology that was previously used to describe pancreatic and peripancreatic collections. As such, use of the terms acute pseudocyst and pancreatic abscess is now discouraged. Instead, four distinct collection subtypes are identified on the basis of the presence of pancreatic necrosis and time elapsed since the onset of pancreatitis. Acute peripancreatic fluid collections (APFCs) and pseudocysts occur in IEP and contain fluid only. Acute necrotic collections (ANCs) and walled-off necrosis (WON) occur only in patients with necrotizing pancreatitis and contain variable amounts of fluid and necrotic debris. APFCs and ANCs occur within 4 weeks of disease onset. After this time, APFCs or ANCs may either resolve or persist, developing a mature wall to become a pseudocyst or a WON, respectively. Any collection subtype may become infected and manifest as internal gas, though this occurs most commonly in necrotic collections. In this review, the authors present a practical image-rich guide to the revised Atlanta classification system, with the goal of fostering implementation of the revised system into radiology practice, thereby facilitating accurate communication among clinicians and reinforcing the radiologist's role as a key member of a multidisciplinary team in treating patients with acute pancreatitis. (©)RSNA, 2016.

Direct MRI-guided biopsy of the prostate: use of post-biopsy needle track imaging to confirm targeting.

PURPOSE: To report the observation that in-plane post-biopsy T2-weighted MRI often demonstrates the needle track as a transient visible linear tissue distortion during direct MRI-guided biopsy. MATERIALS AND METHODS: We retrospectively identified 11 prostatic lesions in 9 men that underwent direct MRI-guided biopsy and in which post-biopsy images were obtained in the plane of the biopsy needle. RESULTS: In 9 of 11 targets, a post-biopsy needle track was visible as a linear tissue distortion on in-plane T2-weighted images obtained at a mean interval of 6 min (range 3-15). In these nine cases, the needle track traversed the intended target, and the biopsy was positive for malignancy in six. Biopsy was positive in one of two cases where the needle track was not visible. In five targets, one or more delayed series were obtained after a mean interval of 21 min (range 8-33), showing the track was no longer visible (n = 3) or was of progressively decreased conspicuity (n = 2). CONCLUSION: Accurate targeting during direct MRI-guided biopsy of the prostate can be confirmed by obtaining post-biopsy in-plane images, since the needle track is usually visible as a transient linear tissue distortion.

Ovarian malignant germ cell tumors: cellular classification and clinical and imaging features.

Ovarian malignant germ cell tumors (OMGCTs) are heterogeneous tumors that are derived from the primitive germ cells of the embryonic gonad. OMGCTs are rare, accounting for about 2.6% of all ovarian malignancies, and typically manifest in adolescence, usually with abdominal pain, a palpable mass, and elevated serum tumor marker levels, which may serve as an adjunct in the initial diagnosis, monitoring during therapy, and posttreatment surveillance. Dysgerminoma, the most common malignant germ cell tumor, usually manifests as a solid mass. Immature teratomas manifest as a solid mass with scattered foci of fat and calcifications. Yolk sac tumors usually manifest as a mixed solid and cystic mass. Capsular rupture or the bright dot sign, a result of increased vascularity and the formation of small vascular aneurysms, may be present. Embryonal carcinomas and polyembryomas rarely manifest in a pure form and are more commonly part of a mixed germ cell tumor. Some OMGCTs have characteristic features that allow a diagnosis to be confidently made, whereas others have nonspecific features, which make them difficult to diagnose. However, imaging features, the patient's age at presentation, and tumor markers may help establish a reasonable differential diagnosis. Malignant ovarian germ cell tumors spread in the same manner as epithelial ovarian neoplasms but are more likely to involve regional lymph nodes. Preoperative imaging may depict local extension, peritoneal disease, and distant metastases. Suspicious areas may be sampled during surgery. Because OMGCTs are almost always unilateral and are chemosensitive, fertility-sparing surgery is the standard of care.

Targeted biopsy of the prostate.

Diagnostic multiparametric MRI of the prostate has steadily evolved over the last three decades and can now reliably depict the dominant tumor in most men with prostate cancer. In response, several methods of targeted biopsy to direct tissue sampling of suspected tumor foci seen at multiparametric MRI have been developed and successfully tested in recent years, including software-assisted MRI-ultrasound (US) fusion biopsy and direct MRI-guided in-bore biopsy. These advances are leading to a sea change in the approach to prostate cancer diagnosis, with the traditional approach of blind systematic biopsy increasingly being replaced by MRI directed targeted biopsy. This review aims to describe the current status of targeted biopsy, with an emphasis on the relative accuracy of different techniques. The results of several critical large multicenter trials are presented, while unanswered questions that require more research are highlighted.

Imaging update on gallbladder adenomyomatosis and its mimics.

Radiologists across many imaging modalities commonly encounter gallbladder adenomyomatosis. The classic imaging appearances of gallbladder adenomyomatosis are well described and confirm benignity. However, in clinical practice, adenomyomatosis can be challenging to differentiate from other gallbladder pathologies that require cholecystectomy. In this article, we describe the common and uncommon appearances of gallbladder adenomyomatosis on multimodality imaging, helping differentiate adenomyomatosis from non-benign gallbladder abnormalities. Accurately differentiating adenomyomatosis from its mimics provides the surgical team with important clinical and surgical management information, improving patient outcomes.

Pelvic applications of MR-guided high intensity focused ultrasound.

MR-guided high intensity focused ultrasound (MRg HIFU) is a novel method of tissue ablation that incorporates high energy focused ultrasound for tissue heating and necrosis within an MR scanner that provides simultaneous stereotactic tissue targeting and thermometry. To date, MRg HIFU has been used primarily to treat uterine fibroids, but many additional applications in the pelvis are in development. This article reviews the basic technology of MRg HIFU, and the use of MRg HIFU to treat uterine fibroids, adenomyosis, and prostate cancer.

MRI appearance of BRCA-associated prostate cancer.

Despite advances in diagnosis and treatment, prostate cancer remains the second leading cause of cancer related mortality in men. Prognosis is variable and dependent on several clinical and genetic factors, including BRCA gene mutations. Recent clinical studies have reported that BRCA-associated prostate cancer is a more aggressive subtype with a higher probability of nodal involvement and distant metastases at the time of diagnosis, but radiological findings have not been described. Accurate recognition of those tumors could help guide clinical management and prompt testing and counseling for BRCA mutations. We have recently encountered four patients with BRCA-associated prostate cancer who underwent multiparametric MRI. The MRI appearances of these tumors, which were generally locally advanced and aggressive in appearance, are presented to facilitate recognition of BRCA-associated prostate cancer and guide potential genetic testing and counseling.

Intermediate-term oncological outcomes after a negative endorectal coil multiparametric MRI of the prostate in patients without biopsy proven prostate cancer.

PURPOSE: Investigate the intermediate-term oncological outcome after negative multiparametric MRI (mpMRI) of the prostate in patients without biopsy proven prostate cancer (PCa). METHODS: The retrospective study included 121 patients with negative mpMRI (Prostate Imaging Reporting and Data System version 2.1 category<3) performed at our institution between 2012 and 2017 without known biopsy proven PCa. Clinical and pathological data were collated including post-MRI prostatic tissue diagnoses with highest Grade Group and most recent prostate specific antigen (PSA) levels up to any definitive prostate cancer treatment. Mean PSA velocities between patients with and without a subsequent diagnosis of Grade Group 2 or higher (GG2+) PCa were compared, and an optimal threshold value was calculated. RESULTS: Outcome data available included PSA values in 117 patients and prostate tissue sampling in 52 patients. Over a median follow up interval of 49.8 months, only 11 of 121 patients (9.1%) were diagnosed with GG2+ PCa, 10 patients (8.3%) with GG1 PCa, and 31 patients (25.6%) had negative prostate tissue samples. Mean PSA velocity was significantly higher in the patients diagnosed with GG2+ PCa (3.87 ng/mL/year) compared to those not diagnosed with GG2+ PCa (-0.71 ng/mL/year, p < 0.001). A threshold PSA velocity of 0.27 ng/mL/year had a 100% sensitivity and 69.8% specificity for GG2+ PCa (AUC: 0.898). CONCLUSION: <10% of patients with negative mpMRI without prior biopsy proven PCa were diagnosed with GG2+ PCa over median follow up of over four years and were associated with PSA velocity of ≥0.27 ng/mL/year. PSA monitoring may be a reasonable management strategy in patients with a negative mpMRI without biopsy proven PCa.