US-guided Interventions Research Articles

To stop or not to stop novel oral anticoagulants prior to performing joint interventional maneuvers? Evidence from a prospective study that the therapy can be maintained.

Anticoagulation is common in patients undergoing routine musculoskeletal interventional maneuvers. Previous retrospective studies have established the safety of continuing anticoagulation with novel oral anticoagulants (NOACs) when performing this kind of interventions. Indeed, ultrasound (US)-guided interventional maneuvers have shown a superior safety profile compared to blind anatomical maneuvers. To evaluate prospectively the periprocedural bleeding events in NOAC-anticoagulated patients undergoing interventional articular or periarticular procedures. Consecutive patients diagnosed with inflammatory or degenerative rheumatologic pathology requiring interventional maneuvers were prospectively recruited. Group 1 was treated with NOACs, group 2 was treated with vitamin K antagonists, and group 3 was not anticoagulated. Prior to the international maneuver, NOAC therapy was continuously administered, in regimens dictated by the underlying anticoagulation indication. Demographics, comorbidities, laboratory parameters, locally administered medication (corticosteroids or viscosupplementation), interventional maneuver location, needle size, and local bleeding events were recorded. Post-procedural control was performed at 30 min, 48 h, and 7 days. No articular/periarticular bleeding event occurred in patients treated with NOACs, regardless of their type and dosage, locally administered medication, needle size, location, and number of interventions per individual. Several patients in all groups developed small superficial ecchymoses at the injection site. Our results suggest that NOACs are safe to be used in a continuous regimen prior to US-guided injections, even as dual antithrombotic therapy (in combination with aspirin). The use of lower gauge needles, chosen for viscosupplementation therapy, was not burdened with adverse effects on the procedural outcome. Key Points • Currently, no prospective studies have been performed to establish the safety of continuous NOAC anticoagulation when performing routine intra- or periarticular interventional maneuvers. • The study offers an extensive view on a wide spectrum of intra- and periarticular interventional maneuvers including anatomic targets and needle sizes that were not previously assessed. • The study offers a perspective into performing repetitive maneuvers in the same patient, both over a short time and at longer intervals. • The zero periprocedural bleeding risk observed in our study may reassure practitioners and suggest that US-guided interventional therapeutic interventions are safe in patients treated with a continuous regimen of different NOACs.

US-Guided Interventional Procedures for Total Hip Arthroplasty.

In patients with total hip arthroplasty (THA) with recurrent pain, symptoms may be caused by several conditions involving not just the joint, but also the surrounding soft tissues including tendons, muscles, bursae, and peripheral nerves. US and US-guided interventional procedures are important tools in the diagnostic work-up of patients with painful THA given that it is possible to reach a prompt diagnosis both directly identifying the pathological changes of periprosthetic structures and indirectly evaluating the response and pain relief to local injection of anesthetics under US monitoring. Then, US guidance can be used for the aspiration of fluid from the joint or periarticular collections, or alternatively to follow the biopsy needle to collect samples for culture analysis in the suspicion of prosthetic joint infection. Furthermore, US-guided percutaneous interventions may be used to treat several conditions with well-established minimally invasive procedures that involve injections of corticosteroid, local anesthetics, and platelet-rich plasma or other autologous products. In this review, we will discuss the clinical and technical applications of US-guided percutaneous interventional procedures in painful THA that can be used in routine daily practice for diagnostic and therapeutic purposes.

Ultrasound-Guided vs. Fluoroscopy-Guided Interventions for Back Pain Management: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

The objective of this study was to compare the outcomes of the ultrasound- and fluoroscopy-guided techniques in the management of back pain. Using PubMed, Scopus, and the Cochrane Library, we searched randomized controlled trials (RCTs) published before May 2023, which reported relevant data on the topic. The effectiveness of the ultrasound-guided (US-guided) and fluoroscopy-guided (FL-guided) approaches for back pain management was compared in terms of postoperative pain intensity, postoperative functional outcomes, and postoperative complications. Subgroup analyses were conducted for different postoperative periods. Eight studies were included in the analysis. There was no significant difference in post-procedural pain relief at one week, two weeks, one month, two months, and three months between the US-guided and FL-guided interventions for back pain management (SMD with 95% CI is -0.01 [-0.11, 0.10]), p = 0.91, I2 = 0%). In terms of the postoperative functional outcomes assessed by the "Oswestry Disability Index" (ODI) functionality score, the model tends to favor the FL-guided injections over the US-guided injections (SMD with 95% CI: 0.13 [-0.00, 0.25], p = 0.05, I2 = 0). Finally, the US-guided and FL-guided injections did not show significantly different results in terms of postoperative complications (RR with 95% CI is 0.99 [0.49, 1.99], p = 0.97, I2 = 0). The subgroup analysis also did not demonstrate differences between the US-guided and FL-guided techniques in the following outcomes: vasovagal reaction, transient headache, and facial flushing. There was no significant difference between the US-guided and FL-guided injections for treating back pain in terms of postoperative pain intensity and complications. Still, the model tends to favor the FL-guided injections over the US-guided injections in terms of functionality.

Added value of 3D ultrasound image-guided hepatic interventions by X matrix technology

BackgroundImage-guided hepatic interventions are integral to the management of infective and neoplastic liver lesions. Over the past decades, 2D US was used for guidance of hepatic interventions; with the recent advances in US technology, 3D US was used to guide the hepatic interventions. This study aimed to illustrate the added value of 3D image-guided hepatic interventions by X matrix technology.MethodsThis prospective study was performed on 100 patients that were divided into two groups: group A which included 50 patients who were managed by using 2D US probe guidance, and group B which included 50 patients who were managed by using 3D X matrix US probe guidance. Thermal ablation was done for 70 patients; 40 radiofrequency ablation (RFA) (20 by the 2D probe and 20 by the 3D X matrix probe) and 30 microwave ablation (MWA) (15 by the 2D probe and 15 by the 3D X matrix probe). Chemical ablation (PEI) was done for 20 patients (ten by the 2D probe and ten by the 3D X matrix probe). Drainage of hepatic collections and biopsy from undiagnosed hepatic focal lesions were done for ten patients (five by the 2D probe and five by the 3D X matrix probe).ResultsThe efficacy of US-guided hepatic interventions by 3D X matrix probe was higher than the 2D probe but not significantly higher, with a p value of 0.705, 0.5428 for RFA and MWA, respectively, 0.5312 for PEI, and 0.2918 for drainage of hepatic collections and biopsy. The complications related to the use of the 3D X matrix probe were significantly lower than the 2D probe with a p value of 0.003. The timing of the procedure was shorter by the usage of a 3D X matrix probe in comparison with the 2D probe with a p value of 0.08, 0.34 for RFA and PEI and significantly shorter for MWA and drainage of hepatic collection, biopsy with a p value of 0.02, 0.001, respectively.Conclusions3D US-guided hepatic interventions by X matrix probe have better efficacy, less complication, and shorter time of procedure than the 2D US-guided hepatic interventions.

Bridging the simulation-to-real gap for AI-based needle and target detection in robot-assisted ultrasound-guided interventions

BackgroundArtificial intelligence (AI)-powered, robot-assisted, and ultrasound (US)-guided interventional radiology has the potential to increase the efficacy and cost-efficiency of interventional procedures while improving postsurgical outcomes and reducing the burden for medical personnel.MethodsTo overcome the lack of available clinical data needed to train state-of-the-art AI models, we propose a novel approach for generating synthetic ultrasound data from real, clinical preoperative three-dimensional (3D) data of different imaging modalities. With the synthetic data, we trained a deep learning-based detection algorithm for the localization of needle tip and target anatomy in US images. We validated our models on real, in vitro US data.ResultsThe resulting models generalize well to unseen synthetic data and experimental in vitro data making the proposed approach a promising method to create AI-based models for applications of needle and target detection in minimally invasive US-guided procedures. Moreover, we show that by one-time calibration of the US and robot coordinate frames, our tracking algorithm can be used to accurately fine-position the robot in reach of the target based on 2D US images alone.ConclusionsThe proposed data generation approach is sufficient to bridge the simulation-to-real gap and has the potential to overcome data paucity challenges in interventional radiology. The proposed AI-based detection algorithm shows very promising results in terms of accuracy and frame rate.Relevance statementThis approach can facilitate the development of next-generation AI algorithms for patient anatomy detection and needle tracking in US and their application to robotics.Key points• AI-based methods show promise for needle and target detection in US-guided interventions.• Publicly available, annotated datasets for training AI models are limited.• Synthetic, clinical-like US data can be generated from magnetic resonance or computed tomography data.• Models trained with synthetic US data generalize well to real in vitro US data.• Target detection with an AI model can be used for fine positioning of the robot.Graphical

Features of Drainage of the Implant Placement Area in Patients with Incisional Ventral Hernias

Introduction. There are different and sometimes conflicting points of view regarding the drainage of the implant placement area in patients with postoperative ventral hernias. This is due to the variability of drainage methods and the commitment of surgeons to one or another technique. In addition, the results of surgical treatment and features of the postoperative period differ in these patients. Current contradictions in the drainage techniques and management of patients with seromas after hernioplasty for PVH determine the relevance of this issue and the need to obtain additional data on benefits and drawbacks of one method or another.The aim of the study was to analyse clinical outcomes of patients with postoperative ventral hernias depending on the drainage technique of the implant placement area.Methods. The study included 392 patients diagnosed with postoperative ventral hernia, who were treated in GBUZ "Samara Regional Clinical Hospital named after V.D. Seredavin" in 2017-2020. Patients clinical outcomes were compared and analysed. Group I included 110 patients with passive drain of the surgical wound, group II included 282 patients with active drain. The groups were assessed based on major parameters of the drainage impact on the surgical treatment outcomes. Non-parametric values were compared by calculating the chi-square (2), parametric - by calculating the Student's t-score. Results. In group I, the average duration of hospitalization was 22,564,45 bed-days. The average terms of drainage were 2,020,69 days. Clinically significant seroma was diagnosed in 35 (32%) patients. The average number of US-guided puncture-drainage interventions was 1,870,89 procedures. Suppuration of the surgical wound was diagnosed in 16 (14,5%) patients. The postoperative mortality rate in the group was 3,6%, 4 patients died. In group II, the average duration of hospitalization was 13,572,92 bed-days. The average terms of drainage were 6,332,12 days. Clinically significant seroma was diagnosed in 42 (14,9%) patients. The average number of US-guided puncture-drainage interventions was 0,650,39 procedures. Suppuration of the surgical wound was diagnosed in 21 (7,4%) patients. The postoperative mortality rate was 2,1%, 6 patients died.Conclusion. Active drain of the implant placement area in patients with postoperative ventral hernias statistically significantly reduces the duration of patients stay in hospital (Student t-score = 11,51 p0,01), frequency of clinically diagnosed seromas (2 = 14,36, p0,01), frequency of suppuration of postoperative wounds (2 = 4,665, p0,05). When choosing the drainage option for the implant placement area, preference of choice should be given to active penetrating open drain or active penetrating closed drain.

Technical Report of Color Doppler Ultrasonography-Assisted Lumbar Spinal Interventions.

Ultrasonography (US) has recently been used more frequently during interventions involving the lumbar spine. However, physicians who are more familiar with musculoskeletal US targeting muscles, tendons, and nerves may find it challenging to perform US-guided lumbar spine interventions using only bony landmarks. This study described the use of color Doppler US for the visualization of the lumbar spinal blood supply to identify vascular landmarks in addition to bony landmarks and thus more easily and accurately perform lumbar spine interventions.

US-guided Interventions to Diagnose and Treat Gynecologic and First-Trimester Disease.

US-guided procedures have an essential role in the diagnosis and treatment of multiple obstetric and gynecologic conditions, can be performed with either transvaginal or transabdominal approaches, and include biopsy of masses, aspiration of fluid collections, injection of therapeutic materials, and saline-infused sonohysterography and hysterosalpingo contrast-enhanced sonography. The full digital presentation is available online. ©RSNA, 2021.

Accuracy and Feasibility of Ultrasound-Guided Intra-articular Injection of the Rat Hip Joint

Intra-articular injection is frequently used as an effective diagnostic and treatment tool for hip joint diseases. However, the underlying treatment mechanism remains unclear because of a lack of experimental animal models. A challenge facing researchers is how to accurately and consistently perform injections involving animal hip joints. The purpose of this study, then, was to establish an ultrasound (US)-guided intra-articular (IA) injection technique using rat hip joints and to evaluate its accuracy and feasibility versus a fluoroscopy (FL)-guided technique. For this study, 20 US-guided and 20 FL-guided IA injections were administered to separate groups of Sprague-Dawley rats. For each procedure, 50 μL of iohexol was injected into the hip joint using a 25G needle. The US-guided injections were performed using a linear probe, and the FL-guided IA injections were performed using C-arm X-ray fluoroscopy. All injections were verified by computed tomography imaging. The number of successful injections and needle repositions per injection, as well as operating times, were recorded, and the rats were observed for complications for 10 d after the injections. Statistical analysis was used to compare US-guided and FL-guided techniques with significance set at p < 0.05. The success rate was markedly higher for the US-guided interventions (90%) than for the FL-guided interventions (75%) (p<0.05). The intervention time was shorter in the US-guided group (95.95 ± 8.376 s) than in the FL-guided group (110.70 ± 20.236 s) (p < 0.05), and the median number of needles repositioned per injection in the US-guided group (1.20 ± 0.41) was notably less than that in the FL-guided group (1.60 ± 0.68) (p < 0.05). A puncture site hematoma was noted in two rat hips (10%) the day after injection in the FL-guided group. Overall, the study indicated that ultrasound-guided intra-articular injection of the hip is a feasible, accurate and safe method for use in rats. This makes it a promising tool for diagnosing coxofemoral pain, producing hip osteoarthritis animal models and administering intra-articular medication.

3D ultrasound guided navigation system with hybrid image fusion

A prototype of a navigation system to fuse two image modalities is presented. The standard inter-modality registration is replaced with a tracker-based image registration of calibrated imaging devices. Intra-procedure transrectal US (TRUS) images were merged with pre-procedure magnetic resonance (MR) images for prostate biopsy. The registration between MR and TRUS images was performed by an additional abdominal 3D-US (ab-3D-US), which enables replacing the inter-modal MR/TRUS registration by an intra-modal ab-3D-US/3D-TRUS registration. Calibration procedures were carried out using an optical tracking system (OTS) for the pre-procedure image fusion of the ab-3D-US with the MR. Inter-modal ab-3D-US/MR image fusion was evaluated using a multi-cone phantom for the target registration error (TRE) and a prostate phantom for the Dice score and the Hausdorff distance of lesions . Finally, the pre-procedure ab- 3D-US was registered with the TRUS images and the errors for the transformation from the MR to the TRUS were determined. The TRE of the ab-3D-US/MR image registration was 1.81 mm. The Dice-score and the Hausdorff distance for ab-3D-US and MR were found to be 0.67 and 3.19 mm. The Dice score and the Hausdorff distance for TRUS and MR were 0.67 and 3.18 mm. The hybrid navigation system showed sufficient accuracy for fusion guided biopsy procedures with prostate phantoms. The system might provide intra-procedure fusion for most US-guided biopsy and ablation interventions.

Scrubbing needles: a simple and costless technique to improve needle tip visibility during US-guided liver interventions.

To evaluate the echogenicity of a commercially available needle, modified on the tip, by comparing two groups of patients undergoing to percutaneous biliary drainage. In this retrospective analysis 16 percutaneous transhepatic biliary drainage (PTBD) procedures performed on 16 oncologic patients were evaluated. Patients were randomly divided into two groups of eight subjects each; in the first group, a standard needle was adopted (group A); in the second group, the needle was manually modified to create a rough surface (group B), by scrubbing the tip with an 11 scalpel blade for 150s all around its surface. To objectively quantify US needle tip visibility, the contrast-to-noise ratio (CNR) was calculated analyzing B-mode images by positioning region of interests in correspondence of needle tip and liver parenchyma. Needle tip echogenicity was significantly higher in group B where the needle tip was modified compared to control group A (p value = 0.014). CNR, considered to objectively evaluate differences among needle tip echogenicity, was significantly higher in group B with respect to control group A (p value = 0.018). The proposed method, scrubbing a 22 gauge commercially available needle tip with a scalpel blade, represents an effective technique to improve needle visibility during US-guided punctures of the liver.

Contrast-Enhanced Ultrasound-Guided Interventions-The New Sheriff in Town?: A Case-Based Review of Problem Solving With Ultrasound Contrast.

Ultrasound (US)-guided intervention is a well-established medical procedure and offers advantages such as real-time guidance, portability, reduced cost, shortened procedure time compared with computed tomography, and lack of ionizing radiation. Ultrasound contrast agents (UCAs) are a useful adjunct to US-guided procedures. The addition of microbubble UCAs during US-guided interventions can assist with biopsy planning and lesion selection, aid in identification of target lesions, and direct the biopsy toward viable tissue. Ultrasound contrast agents have been in use outside of the United States for many years and have been used off label at select institutions across the United States before the Food and Drug Administration approval of Lumason (Bracco Diagnostics) for liver lesion evaluation in April 2016. After Food and Drug Administration approval, the use of UCAs has expanded rapidly, and UCAs are being used for a variety of clinical applications. Ultrasound contrast agents have been shown to be safe, and there is no renal toxicity. In this article, we will discuss the indications and techniques for using contrast-enhanced ultrasound during US-guided interventions, and we will present case examples where contrast-enhanced ultrasound added value.

Real-world Outcomes of Ultrasonography-guided Interventions in a Tertiary Hospital.

Background:Intervention under ultrasonography (US) guidance has become increasingly prevalent in recent years. This study aimed to assess the treatment response to US-guided musculoskeletal interventions in daily practice.Methods:This retrospective study sought to identify the treatment response to US-guided interventions in different tissues conducted between January 2017 and December 2018. The treatment response to various US-guided interventions in different tissues was recorded. The response was further classified into positive response and negative response according to the improvement of symptoms or satisfaction of the treatment.Results:Among the 605 interventions included for data analysis, a positive response rate of 81% was observed in this study for all US-guided interventions, ranging from 70% to 88% in different categories.Conclusion:This real-world analysis demonstrated the effectiveness of various US-guided interventions without serious complications. We recommend US as a useful guidance for a variety of injections.

Ultrasound-Guided Treatment of Extrusive Medial Meniscopathy: A 3-Step Protocol.

Medial knee pain is commonplace in clinical practice and can be related to several pathologic conditions: ie, medial plica syndrome, saphenous nerve entrapment, pes anserine syndrome, medial collateral ligament injury, and medial meniscus disorders. Ultrasound (US) imaging represents a valuable first-line diagnostic approach to adequately visualize the superficial structures in the medial compartment of the knee to easily plan for prompt treatment. Currently, the management of chronic degenerative diseases involving the menisci, and causing their extrusion, consists of surgery (arthroscopic partial meniscectomy). This procedure often allows only a partial resolution of pain and functional impairment. In the pertinent literature, US-guided interventions for the medial meniscus are proposed, mainly to decrease pain and inflammation or to induce regeneration. Likewise, this Technical Innovation describes in detail the US findings of medial extrusive meniscopathy and also illustrates a novel US-guided technique to treat the bursa of the medial collateral ligament, the extruded fragment of the medial meniscus, and the synovial parameniscal recesses simultaneously.

Ultrasound-guided treatment of peripheral entrapment mononeuropathies.

The advent of high-resolution neuromuscular ultrasound (US) has provided a useful tool for conservative treatment of peripheral entrapment mononeuropathies. US-guided interventions require careful coordination of transducer and needle movement along with a detailed understanding of sonoanatomy. Preprocedural planning and positioning can be helpful in performing these interventions. Corticosteroid injections, aspiration of ganglia, hydrodissection, and minimally invasive procedures can be useful nonsurgical treatments for mononeuropathies refractory to conservative care. Technical aspects as well as the current understanding of the indications and efficacy of these procedures for common entrapment mononeuropathies are reviewed in this study. Muscle Nerve, 2019.

Improving the Performance Time and Accuracy of Ultrasound-Guided Interventions: A Randomized Controlled Double-Blind Trial of the Line-of-Sight Approach and the "APPLES" Mnemonic.

To determine whether the line-of-sight approach improved the performance time and accuracy of ultrasound (US)-guided needle placement targeting the subdeltoid bursa in a cadaver among novice operators compared to the side approach. A secondary objective was to determine whether participants thought the APPLES (angle, position, perpendicular, line up, entry, sweep) mnemonic was a helpful guide for performing the procedure. Medical students and residents were randomized into either a line-of-sight or side approach group and then crossed over to the other group. The procedure time was determined by 2 blinded reviewers. A survey was administered to determine which method participants preferred and whether they thought the APPLES mnemonic was helpful. A paired t test was used to compare the performance time, and the McNemar test was used to compare the accuracy of the methods. Among the 110 participants, the performance time with the line-of-sight approach (mean, 14.4 seconds; SD, 9.95 seconds) was significantly decreased compared to the side approach (mean, 18.6 seconds; SD, 10.1 seconds; P = .00029). Additionally, participants who only hit the target using one method were more likely to hit the target in 30 seconds using the line-of-sight approach (P = .035). In total, 72.7% of participants preferred the line-of-sight approach over the side approach, and 88.2% of participants thought that APPLES mnemonic was useful. This study highlights the finding that positioning of the operator is important in performing US-guided interventions, and the line-of-sight approach may improve the performance time and accuracy among novice operators. Furthermore, the APPLES mnemonic serves as a useful educational tool for teaching US-guided interventional procedures.

DEGUM Recommendations on Infection Prevention in Ultrasound and Endoscopic Ultrasound

Microbial contamination of ultrasound probes for percutaneous or endoscopic use is common. However, infectious diseases caused by transmission of microorganisms by US procedures have rarely been reported. In Germany, legal regulations address hygiene in ultrasound procedures. Based on these regulations and the available literature, an expert panel of the German Society of Ultrasound in Medicine (DEGUM) has formulated sophisticated recommendations on hygienic measures in percutaneous and endoscopic US, including US-guided interventions.

Real-time non-rigid target tracking for ultrasound-guided clinical interventions

Biological motion is a problem for non- or mini-invasive interventions when conducted in mobile/deformable organs due to the targeted pathology moving/deforming with the organ. This may lead to high miss rates and/or incomplete treatment of the pathology. Therefore, real-time tracking of the target anatomy during the intervention would be beneficial for such applications.Since the aforementioned interventions are often conducted under B-mode ultrasound (US) guidance, target tracking can be achieved via image registration, by comparing the acquired US images to a separate image established as positional reference. However, such US images are intrinsically altered by speckle noise, introducing incoherent gray-level intensity variations. This may prove problematic for existing intensity-based registration methods. In the current study we address US-based target tracking by employing the recently proposed EVolution registration algorithm. The method is, by construction, robust to transient gray-level intensities. Instead of directly matching image intensities, EVolution aligns similar contrast patterns in the images. Moreover, the displacement is computed by evaluating a matching criterion for image sub-regions rather than on a point-by-point basis, which typically provides more robust motion estimates. However, unlike similar previously published approaches, which assume rigid displacements in the image sub-regions, the EVolution algorithm integrates the matching criterion in a global functional, allowing the estimation of an elastic dense deformation.The approach was validated for soft tissue tracking under free-breathing conditions on the abdomen of seven healthy volunteers. Contact echography was performed on all volunteers, while three of the volunteers also underwent standoff echography. Each of the two modalities is predominantly specific to a particular type of non- or mini-invasive clinical intervention. The method demonstrated on average an accuracy of ∼1.5 mm and submillimeter precision. This, together with a computational performance of 20 images per second make the proposed method an attractive solution for real-time target tracking during US-guided clinical interventions.

State of education regarding ultrasound-guided interventions during pain fellowships in Korea: a survey of recent fellows.

BackgroundRecently, the use of ultrasound (US) techniques in regional anesthesia and pain medicine has increased significantly. However, the current extent of training in the use of US-guided pain management procedures in Korea remains unknown. The purpose of the present study was to assess the current state of US training provided during Korean Pain Society (KPS) pain fellowship programs through the comparative analysis between training hospitals.MethodsWe conducted an anonymous survey of 51 pain physicians who had completed KPS fellowships in 2017. Items pertained to current US practices and education, as well as the types of techniques and amount of experience with US-guided pain management procedures. Responses were compared based on the tier of the training hospital.ResultsAmong the 51 respondents, 14 received training at first- and second-tier hospitals (Group A), while 37 received training at third-tier hospitals (Group B). The mean total duration of pain training during the 1-year fellowship was 7.4 months in Group A and 8.4 months in Group B. Our analysis revealed that 36% and 40% of respondents in Groups A and B received dedicated US training, respectively. Most respondents underwent US training in patient-care settings under the supervision of attending physicians. Cervical root, stellate ganglion, piriformis, and lumbar plexus blocks were more commonly performed by Group B than by Group A (P < 0.05).ConclusionsInstruction regarding US-guided pain management interventions varied among fellowship training hospitals, highlighting the need for the development of educational standards that mandate a minimum number of US-guided nerve blocks or injections during fellowships in interventional pain management.

Ultrasound-guided genitourinary interventions: principles and techniques.

Ultrasound (US) is often used to guide various interventional procedures in the genitourinary (GU) tract because it can provide real-time imaging without any radiation hazard. Moreover, US can clearly visualize the pathway of an aspiration or biopsy needle to ensure the safety of the intervention. US guidance also helps clinicians to access lesions via the transabdominal, transhepatic, transvaginal, transrectal, and transperineal routes. Hence, US-guided procedures are useful for radiologists who wish to perform GU interventions. However, US-guided procedures and interventions are difficult for beginners because they involve a steep initial learning curve. The purpose of this review is to describe the basic principles and techniques of US-guided GU interventions.