Safety and effectiveness of transsplenic access for portal venous interventions: a single-center retrospective study.

PURPOSE: To assess the safety and effectiveness of percutaneous transsplenic access (PTSA) for portal vein (PV) interventions among patients with PV disease. MATERIALS AND METHODS: Adult patients with PV disease were enrolled if they required percutaneous catheterization for PV angioplasty, embolization, thrombectomy, variceal embolization, or transjugular intrahepatic portosystemic shunt (TIPS) placement for a difficult TIPS or recanalization of a chronically occluded PV. The procedures were performed between January 2018 and January 2023. Patients were excluded if they had an active infection, had a chronically occluded splenic vein malignant infiltration of the needle tract, had undergone splenectomy, or were under age 18 years. RESULTS: Thirty patients (15 women, 15 men) were enrolled. Catheterization of the PV through PTSA succeeded for 29 of 30 patients (96.7%). The main adverse effect recorded was flank pain in 5 of 30 cases (16.7%). No bleeding events from the spleen, splenic vein, or percutaneous access point were recorded. Two cases (6.7%) each of hepatic bleeding and rethrombosis of the PV were reported, and a change in hemoglobin levels (mean [SD], - 0.5 [1.4] g/dL) was documented in 14 cases (46.7%). CONCLUSION: PTSA as an approach to accessing the PV is secure and achievable, with minimal risk of complications. Minimal to no bleeding is possible by using tract closure methods.

Single-arm prospective study comparing ablation zone volume between time zero and 24 h after microwave ablation of liver tumors.

PURPOSE: Percutaneous thermal ablation is an effective treatment for primary and metastatic liver tumors and is a recommended local therapy for early-stage hepatocellular carcinoma (HCC). Reported evidence shows an increase in the ablation zone volume over the first 24-h post-liver ablation. This report compares ablation zone volumes immediately at the completion (T = 0) of 26 microwave ablations of liver tumors to 24-h post-procedure (T = 24) volumes. MATERIALS AND METHODS: 20 patients, 13 (65%) males, underwent a total of 26 hepatic microwave ablations (MWA) under ultrasound guidance. Contrast-enhanced CT (CECT) or MRI was performed immediately and another CECT 24 h post operatively. Evaluation of the ablation zone and comparison of the two post-operative scans were done using BioTrace software. The expansion of ablation zones on post-op CECTs was matched point by point per direction. The distance between each 2 points was measured and grouped by distance. The incidence of each specific distance was then converted into a percentage, first for each case separately, then for all cases altogether. Data were tested by a matched paired one-sided t test. RESULTS: The median lesion diameter was 1.5 cm (range 0.5-3.3) with 16 (62%) HCC cases and 9 hepatic metastases (4 neuroendocrine carcinoma, 4 colorectal carcinomas, 1 breast carcinoma, 1 pancreatic cancer). The data show a consistent volume expansion greater than 30% (p = 7.7e-5) 24-h post-ablation, where the median expansion is 57%. Distances between T = 0 and T = 24 equal to 3-7 mm occur in over 35% of the cases. CONCLUSION: The ablation zone expansion at 24-h post-op was not uniform. The final ablation zone is difficult to predict at the time of the procedure. The awareness of the ablation zone expansion is important when treating near-critical structures, managing the heat sink effect, and preserving liver parenchyma.

Percutaneous Transesophageal Gastrostomy: Procedural Technique and Outcomes.

PURPOSE: To demonstrate the safety and effectiveness of percutaneous transesophageal gastrostomy (PTEG) as a palliative option in patients with malignant bowel obstructions (MBOs), and provide a comprehensive review of PTEG indications, placement technique, and short- and long-term outcomes. MATERIALS AND METHODS: Thirty-eight consecutive patients who underwent a PTEG procedure attempt from 2014 to 2022 were included in this analysis. Clinical indications, method of placement, technical and clinical success, adverse events, including procedure-related mortality, and effectiveness were assessed. Technical success was defined as placement of a PTEG. Clinical success was defined as improvement in clinical symptoms following PTEG placement. RESULTS: Of the 38 patients who underwent PTEG, 19 (50%) were men and 19 (50%) were women (median age, 58 years; range, 21-75 years). Three (8%) PTEG placements were performed with the patients under moderate sedation, whereas the remainder (92%) were performed with the patients under general anesthesia. Technical success was achieved in 35 of the 38 (92%) patients. The mean catheter duration was 61 days (median, 29 days; range, 1-562 days), with 5 of the 35 patients requiring tube exchanges after initial placement. Moreover, 7 of the 35 patients with successful PTEG placement experienced an adverse event, including 1 case of non-procedure-related mortality. All patients with successful PTEG placement experienced improvement in clinical symptoms. CONCLUSIONS: PTEG is an effective and safe option for patients with contraindications to traditional percutaneous gastrostomy tube placement in the setting of MBO. PTEG is an effective means of providing palliation and improving the quality of life.

Establishing a telemedicine program for interventional radiology: a study of patient opinion and experience.

PURPOSE The COVID-19 pandemic forced healthcare officials to implement new policies, such as the use of virtual consultations over office-based medical appointments, to reduce the transmission of the virus. The purpose of this study is to quantitatively compare patients' experiences with virtual outpatient telemedicine encounters at a single academic institution in Interventional Radiology (IR) and in-person visits during the course of the COVID-19 pandemic. METHODS The TeleENT Satisfaction Questionnaire and the Medical Communication Competence Scale (MCCS) were used to survey patients' satisfaction with both in-person and virtual office visits. RESULTS Ninety respondents (38 in-person, 52 virtual) acknowledged numerous benefits of virtual visits versus in-person office visits including reductions in time, cost, and potential viral transmission risk during the COVID-19 pandemic. No statistically significant difference was noted, based on a Likert scale from 1 to 7, between in-person and virtual visits (all p > 0.05) for scheduling related factors. No statistically significant difference was noted in any of the MCCS subscales between the two cohorts in regards to medical information communication (all p > 0.05). A majority of patients with virtual encounters (82.7%) stated that it was easy to obtain an electronic device for use during the telemedicine visit, and 73.1% of patients felt that setting up the telemedicine encounter was easy. CONCLUSION This study demonstrates that telemedicine is an acceptable alternative to in-office appointments and could increase access to IR care outside of the traditional physician-patient interaction. With telemedicine visits, patients can communicate their concerns and obtain information from the doctor with noninferior communication compared to in-person visits.

Interventional Radiology Management of Adult Liver Transplant Complications.

Liver transplant remains the definitive therapy for patients with end-stage liver disease. Outcomes have continued to improve, in part owing to interventions used to treat posttransplant complications involving the hepatic arteries, portal vein, hepatic veins or inferior vena cava (IVC), and biliary system. Significant hepatic artery stenosis can be treated with angioplasty or stent placement to prevent thrombosis and biliary ischemic complications. Hepatic arterioportal fistula and hepatic artery pseudoaneurysm are rare complications that can often be treated with endovascular means. Treatment of hepatic artery thrombosis can have mixed results. Portal vein stenosis can be treated with venoplasty or more commonly stent placement. The rarer portal vein thrombosis can also be treated with endovascular techniques. Hepatic venous outflow stenosis of the hepatic veins or IVC is amenable to venoplasty or stent placement. Complications of the bile ducts are the most encountered complication after liver transplant. When not amenable to endoscopic intervention, biliary stricture, bile leak, and ischemic cholangiopathy can be treated with percutaneous transhepatic cholangiography with biliary drainage and other interventions. New techniques have further improved care for these patients. Transsplenic portal vein recanalization has improved transplant candidacy for patients with chronic portal vein thrombosis. Spontaneous splenorenal shunt and splenic artery steal syndrome (nonocclusive hepatic artery hypoperfusion syndrome) remain complicated topics, and the role of endovascular embolization is developing. When patients have recurrence of cirrhosis after transplant, most commonly due to viral hepatitis, transjugular intrahepatic portosystemic shunt (TIPS) may be required to treat symptoms of portal hypertension. Online supplemental material is available for this article. ©RSNA, 2022.

Interventional Management of Acquired Lymphatic Disorders.

The lymphatic system is a complex network of tissues, vessels, and channels found throughout the body that assists in fluid balance and immunologic function. When the lymphatic system is disrupted related to idiopathic, iatrogenic, or traumatic disorders, lymphatic leaks can result in substantial morbidity and/or mortality. The diagnosis and management of these leaks is challenging. Modern advances in lymphatic imaging and interventional techniques have made radiology critical in the multidisciplinary management of these disorders. The authors provide a review of conventional and clinically relevant variant lymphatic anatomy and recent advances in diagnostic techniques such as MR lymphangiography. A detailed summary of technical factors related to percutaneous lymphangiography and lymphatic intervention is presented, including transpedal and transnodal lymphangiography. Traditional transabdominal access and retrograde access to the central lymph nodes and thoracic duct embolization techniques are outlined. Newer techniques including transhepatic lymphangiography and thoracic duct stent placement are also detailed. For both diagnostic and interventional radiologists, an understanding of lymphatic anatomy and modern diagnostic and interventional techniques is vital to the appropriate treatment of patients with acquired lymphatic disorders. ©RSNA, 2022.

Transsplenic Portal System Catheterization: Review of Current Indications and Techniques.

Multiple diseases of the portal system require effective portal vein access for endovascular management. While percutaneous transhepatic and transjugular approaches remain the standard methods of portal vein access, transsplenic access (TSA) has gained recognition as an effective and safe technique to access the portal system in patients with contraindications to traditional approaches. Recently, the utility of percutaneous TSA has grown, with described treatments including recanalization of chronic portal vein occlusion, placement of stents for portal vein stenosis, portal vein embolization of the liver, embolization of gastric varices, placement of complicated transjugular intrahepatic portosystemic shunts, and interventions after liver transplant. The authors provide a review of percutaneous TSA, including indications, a summary of related portal vein diseases, and the different techniques used for access and closure. In addition, an imaging-based review of technical considerations of TSA interventions is presented, with a review of potential procedural complications. With technical success rates that mirror or rival the standard methods and reported low rates of major complications, TSA can be a safe and effective option in clinical scenarios where traditional approaches are not feasible. ©RSNA, 2022.

Venous Anatomy and Collateral Pathways of the Pelvis: An Angiographic Review.

The pelvic venous system is complex, with the potential for numerous pathways of collateralization. Owing to stenosis or occlusion, both thrombotic and nonthrombotic entities in the pelvis may necessitate alternate routes of venous return. Although the pelvic venous anatomy and collateral pathways may demonstrate structural variability, a number of predictable paths often can be demonstrated on the basis of the given disease and the level of obstruction. Several general categories of collateral pathways have been described. These pathway categories include the deep pathway, which is composed of the lumbar and sacral veins and vertebral venous plexuses; the superficial pathway, which is composed of the circumflex and epigastric vessels; various iliofemoral collateral pathways; the intermediate pathway, which is composed of the gonadal veins and the ovarian and uterine plexuses; and portosystemic pathways. The pelvic venous anatomy has been described in detail in cadaveric and anatomic studies, with the aforementioned collateral pathways depicted on CT and MR images in several imaging studies. A comprehensive review of the native pelvic venous anatomy and collateralized pelvic venous anatomy based on angiographic features has yet to be provided. Knowledge of the diseases involving a number of specific pelvic veins is of clinical importance to interventional and diagnostic radiologists and surgeons. The ability to accurately identify common collateral patterns by using multiple imaging modalities, with accurate anatomic descriptions, may assist in delineating underlying obstructive hemodynamics and diagnosing specific occlusive disease entities. ©RSNA, 2022.

Ultrasound-Guided Phrenic Nerve Block for Lung Nodule Biopsy: Single-Center Initial Experience.

RATIONALE AND OBJECTIVES: Biopsy of lung nodules in the lower lung fields can be difficult because of breathing motion. Ipsilateral phrenic nerve block (PNB) before biopsy should make the biopsy safer, easier, and more precisely targeted. We describe the use of ultrasound-guided PNB before lung nodule biopsy, including relevant anatomy and variations, complications, and technique, along with our first 40 cases. MATERIALS AND METHODS: We retrospectively reviewed patients who underwent PNB before computed tomography (CT)- or ultrasound-guided lung nodule biopsy from April 2015 through March 2020. Patient demographics, CT fluoroscopy time, radiation dose, complications, diagnostic yield, and effectiveness of PNB were recorded. Effectiveness of PNB was based on direct observation of diaphragmatic motion. Control group data for biopsies during the same time frame were collected and matched with nodules ≤1 cm from the PNB group. RESULTS: Among 40 patients identified, no complications occurred related to the PNB. Mean (SD) nodule size was 12.4 (6.2) mm. True-positive results were obtained in 39 patients (98%), with 1 false-negative after an ineffective PNB. PNB was effective in 70%. When CT fluoroscopy was used for the biopsy, radiation dose was significantly lower after an effective PNB than an ineffective PNB (p < .001). Effective PNB was significantly more common with injection of ≥4 mL of local anesthetic (p = .01). Comparison with 19 matched controls showed significantly fewer instances of pneumothorax (p = .02) and greater diagnostic success (p = .03) for the PNB group. CONCLUSION: Ultrasound-guided PNB is safe and effective and can improve outcomes when used before lung nodule biopsy.

Percutaneous Image-Guided Ablation of Lung Tumors.

Tumors of the lung, including primary cancer and metastases, are notoriously common and difficult to treat. Although surgical resection of lung lesions is often indicated, many conditions disqualify patients from being surgical candidates. Percutaneous image-guided lung ablation is a relatively new set of techniques that offers a promising treatment option for a variety of lung tumors. Although there have been no clinical trials to definitively compare its efficacy to those of traditional treatments, lung ablation is widely practiced and generally accepted to be safe and effective. Especially encouraging results have recently emerged for cryoablation, one of the newer ablative techniques. This article reviews the indications, techniques, contraindications, and complications of percutaneous image-guided ablation of lung tumors with special attention to cryoablation and its recent developments in protocol optimization.

Prostate Artery Embolization-Review of Indications, Patient Selection, Techniques and Results.

Lower urinary tract symptoms (LUTS) due to benign prostatic hypertrophy (BPH) are a very common problem in men ranging from mild urinary symptoms to recurrent urinary tract infections or renal failure. Numerous treatment options are available ranging from conservative medical therapies to more invasive surgical options. Prostate artery embolization (PAE) has emerged as a novel treatment option for this common problem with clinical efficacy comparable to the current surgical gold standard, transurethral resection of the prostate (TURP). PAE offers fewer complications and side effects without a need for general anesthesia or hospitalization. This review discusses the indications for prostate artery embolization in addition to LUTS, patient evaluation in patients with LUTS, PAE technique and clinical results, with an emphasis on efficacy and safety.

Emerging approaches to pre-hospital hemorrhage control: a narrative review.

In the United States, trauma claims the lives of over 150,000 civilians each year. In military settings, trauma and exsanguination result in 50% of combat related deaths. The majority of these deaths result from uncontrolled non-compressible hemorrhage. Non-compressible hemorrhage often results from deep vascular injuries within the torso, however can also occur secondary to penetrating injuries that involve the extremities. Given the high mortality rates for non-compressible hemorrhage, rapid and effective management of patients suffering from hemorrhage is essential to good patient outcomes. Consequently, there has been increasing interest in solutions for point-of-injury hemorrhage control in trauma and military medicine. Undoubtedly there is a great need for prehospital hemostatic interventions that can be deployed by trained and untrained personnel. Since 2001, various hemostatic agents have been developed, each with its advantages based upon the type and severity of injury, wound size, wound location, accessibility to injury site, and the coagulation status of the patient. These agents are often used in the military setting as a temporizing measure prior to definitive therapy and include techniques such as resuscitative endovascular balloon occlusion of the aorta (REBOA) and bioengineered agents including ResQFoam, RevMedx's XSTAT, Tranexamic acid (TXA), and QuikClot Combat Gauze (QCG). Here, we review the indications, composition, technique, efficacy, and outcomes of these hemostatic agents.

Endovascular interventions in the management of acute extremity trauma: a narrative review.

Minimally invasive endovascular interventions including stenting and embolization have been widely adopted for the treatment of emergent and traumatic thoracoabdominal injuries. In recent years, these techniques have been utilized in the setting of extremity vascular trauma with promising outcomes. By allowing for the rapid diagnosis and subsequent treatment of penetrating or blunt vascular extremity trauma, these techniques can help to minimize blood loss, reduce operative complications, and potentially prevent limb amputation. Here, we present a narrative review of the ever-increasing role of minimally invasive interventions in the management of extremity trauma and compare its use and outcomes to open surgical repair. A special focus is placed on diagnostic imaging modalities in trauma and the role of interventional radiologists in the work-up and treatment of extremity trauma. We discuss diagnostic imaging modalities that aid in the triaging of extremity trauma, such as Doppler sonography, CT angiography, and catheter-based angiography. We present an overview on the literature related to endovascular interventions such as embolotherapy and stent grafting as well as the technical challenges associated with each technique. Finally, we present our own cases on the workup and endovascular treatment of extremity trauma, including CT angiography, particulate and coil embolization, and stent graft placement.

Single-Center Review of Celiac Plexus/Retrocrural Splanchnic Nerve Block for Non-Cancer Related Pain.

RATIONALE AND OBJECTIVES: Celiac plexus and retrocrural splanchnic nerve (CP/RSN) blocks are widely used for cancer-related abdominal pain, but there is limited literature on their efficacy for non-cancer related pain. Our aim was to determine the indications and effectiveness of CT-guided CP/RSN blocks performed on patients with abdominal pain from non-cancer related sources. MATERIALS AND METHODS: CT-guided CP/RSN blocks for non-cancer related abdominal pain from 2011-2020 were retrospectively reviewed for patient demographics, procedure details, duration of pain relief, and complications. Effective blocks were defined as patient-reported pain relief or decrease in opioid use lasting 2 or more days for temporary blocks and 14 or more days for permanent blocks. RESULTS: Of 72 CT-guided CP/RSN blocks for non-cancer related abdominal pain, 48 (67%) were effective for a mean of 51 days (median 14, range 2-700). Of the 18 permanent blocks, 9 (50%) were effective for a mean of 111 days (median 90, range 14-390). Of the 54 temporary blocks, 39 (72%) were effective for a mean of 37 days (median 9, range 2-700). Indications included postural orthostatic tachycardia syndrome/dysautonomia (77% effective, 20/26), pancreatitis (86% effective, 12/14), postsurgical pain (62% effective, 8/13), median arcuate ligament syndrome (70% effective, 7/10), chronic pain syndrome (20% effective, 1/5), gastroparesis (80% effective, 4/5), and renal cystic disease (33% effective, 1/3). For postural orthostatic tachycardia syndrome /dysautonomia, pancreatitis, post-surgical pain, and MALS, there were no statistically significant differences in effectiveness between celiac vs. splanchnic blocks in groups matched by indication and intended duration (temporary/permanent). CONCLUSIONS: CT-guided CP/RSN blocks can effectively manage non-cancer related abdominal pain, though there is discrepancy in efficacy between temporary and permanent blocks.

Application of 3D Printing in Preoperative Planning.

Preoperative planning is critical for success in the surgical suite. Current techniques for surgical planning are limited; clinicians often rely on prior experience and medical imaging to guide the decision-making process. Furthermore, two-dimensional (2D) presentations of anatomical structures may not accurately portray their three-dimensional (3D) complexity, often leaving physicians ill-equipped for the procedure. Although 3D postprocessed images are an improvement on traditional 2D image sets, they are often inadequate for surgical simulation. Medical 3D printing is a rapidly expanding field and could provide an innovative solution to current constraints of preoperative planning. As 3D printing becomes more prevalent in medical settings, it is important that clinicians develop an understanding of the technologies, as well as its uses. Here, we review the fundamentals of 3D printing and key aspects of its workflow. The many applications of 3D printing for preoperative planning are discussed, along with their challenges.

Bland Embolization of Benign Liver Tumors: Review of the Literature and a Single Center Experience.

Transarterial embolization has shown promise as a safe, effective, and less invasive treatment modality for benign liver lesions (hemangioma, focal nodular hyperplasia (FNH), and hepatic adenoma (HA)) with fewer complications compared to surgical intervention. There is no consensus regarding the most appropriate embolization material(s) for the treatment of benign liver tumors. The purpose of this study was to review the current literature regarding the transarterial embolization of benign liver tumors and to share our single center experience. This was a non-blinded, retrospective, single-institution review of the bland embolization of benign liver tumors. Clinical data and imaging before and after embolization were used to evaluate lesion response to transarterial embolization. Twelve patients were included in the study. Five patients with six hemangiomas were treated. Pain was a presenting complaint in all five of these patients. The median change in tumor volume was -12.4% and ranged from -30.1% to +42.3%. One patient with two FNH lesions was treated, and both lesion volumes decreased by more than 50%. Six patients with 10 adenomas were treated. Pain was a presenting complaint in three patients, and five patients had a lesion >5 cm. The median change in tumor volume was -67.0% and ranged from -92.9% to +65.8%. Bland transarterial embolization of liver hemangiomas, FNH, and HA can be an effective and minimally invasive treatment modality to control the size and/or symptoms of these lesions. There is a variable response depending on tumor type and the embolization materials used.

Treatment of Hepatic Artery Stenosis in Liver Transplant Patients Using Drug-Eluting versus Bare-Metal Stents.

Hepatic artery stenosis after liver transplant is often treated with endovascular stent placement. Our institution has adopted use of drug-eluting stents, particularly in small-caliber arteries. We aimed to compare patency rates of drug-eluting stents vs. traditional bare-metal stents. This was a single-institution, retrospective study of liver transplant hepatic artery stenosis treated with stents. Primary patency was defined as time from stent placement to resistive index on Doppler ultrasonography (<0.5), hepatic artery thrombosis, or any intervention including surgery. Fifty-two patients were treated with stents (31 men; mean age, 57 years): 15, drug-eluting stents; 37, bare-metal stents. Mean arterial diameters were 4.1 mm and 5.1 mm, respectively. Technical success was 100% (52/52). At 6 months, 1, 2, and 3 years, primary patency for drug-eluting stents was 80%, 71%, 71%, and 71%; bare-metal stents: 76%, 65%, 53%, and 46% (p = 0.41). Primary patency for small-caliber arteries (3.5-4.5 mm) with drug-eluting stents was 93%, 75%, 75%, and 75%; bare-metal stents: 60%, 60%, 50%, and 38% (p = 0.19). Overall survival was 100%, 100%, 94%, and 91%. Graft survival was 100%, 98%, 96%, and 90%. Stenting for hepatic artery stenosis was safe and effective. While not statistically significant, patency improved with drug-eluting stents compared with bare-metal stents, especially in arteries < 4.5 mm in diameter. Drug-eluting stents can be considered for liver transplant hepatic artery stenosis, particularly in small-caliber arteries.

Imaging findings of pelvic venous insufficiency in patients with postural orthostatic tachycardia syndrome.

OBJECTIVES: Some patients with postural orthostatic tachycardia syndrome (POTS) demonstrate improved dysautonomic symptoms following treatment for pelvic venous insufficiency (PVI). This study assessed the prevalence of significant left common iliac vein (LCIV) compression in POTS patients. METHODS: Radiologists retrospectively reviewed CT images of pelvic veins for 216 women (191 with POTS and 25 age-comparable controls).Quantitative vascular analysis identified percent-diameter compression of the LCIV by the right common iliac artery. Significant LCIV compression was defined as >50%. RESULTS: Significant LCIV compression was found in 69% (131/191) of females with POTS versus 40% (10/25) in controls. The hypothesis that venous compression and presence of POTS are independent was rejected (p = .005). CONCLUSIONS: Significant LCIV compression was noted in a majority of female POTS patients, suggesting that incidence of iliac venous obstruction may be higher than the general population. Patients with POTS and symptoms of PVI may benefit from assessment for venous outflow obstruction.

Diagnostic Yield of Incremental Biopsy Cores and Second Lesion Sampling for In-Gantry MRI-Guided Prostate Biopsy.

BACKGROUND. In-gantry MRI-guided biopsy (MRGB) of the prostate has been shown to be more accurate than other targeted prostate biopsy methods. However, the optimal number of cores to obtain during in-gantry MRGB remains undetermined. OBJECTIVE. The purpose of this study was to assess the diagnostic yield of obtaining an incremental number of cores from the primary lesion and of second lesion sampling during in-gantry MRGB of the prostate. METHODS. This retrospective study included 128 men with 163 prostate lesions who underwent in-gantry MRGB between 2016 and 2019. The men had a total of 163 lesions sampled with two or more cores, 121 lesions sampled with three or more cores, and 52 lesions sampled with four or more cores. A total of 40 men underwent sampling of a second lesion. Upgrade on a given core was defined as a greater International Society of Urological Pathology (ISUP) grade group (GG) relative to the previously obtained cores. Clinically significant prostate cancer (csPCa) was defined as ISUP GG 2 or greater. RESULTS. The frequency of any upgrade was 12.9% (21/163) on core 2 versus 10.7% (13/121) on core 3 (p = .29 relative to core 2) and 1.9% (1/52) on core 4 (p = .03 relative to core 3). The frequency of upgrade to csPCa was 7.4% (12/163) on core 2 versus 4.1% (5/121) on core 3 (p = .13 relative to core 2) and 0% (0/52) on core 4 (p = .07 relative to core 3). The frequency of upgrade on core 2 was higher for anterior lesions (p < .001) and lesions with a higher PI-RADS score (p = .007); the frequency of upgrade on core 3 was higher for apical lesions (p = .01) and lesions with a higher PI-RADS score (p = .01). Sampling of a second lesion resulted in an upgrade in a single patient (2.5%; 1/40); both lesions were PI-RADS category 4 and showed csPCa. CONCLUSION. When performing in-gantry MRGB of the prostate, obtaining three cores from the primary lesion is warranted to optimize csPCa diagnosis. Obtaining a fourth core from the primary lesion or sampling a second lesion has very low yield in upgrading cancer diagnoses. CLINICAL IMPACT. To reduce patient discomfort and procedure times, operators may refrain from obtaining more than three cores or second lesion sampling.