Category Archives: Contrast-Enhanced

Ultrasound in Prostate Disease: Rethinking an Old Standard

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When was the last time you really reconsidered the power of ultrasound in evaluating prostate disease? For many clinicians, TRUS (transrectal ultrasound) is synonymous with biopsy guidance. It’s mechanical, familiar, and perhaps even taken for granted. But prostate ultrasound is evolving. And if you haven’t revisited its capabilities lately, you may be missing a revolution happening in prostate ultrasound.

Prostate ultrasound is no longer just about finding hypoechoic lesions in the peripheral zone. Thanks to modern advancements such as shear wave elastography, micro-ultrasound, and contrast-enhanced imaging, it’s becoming a serious contender against mpMRI in diagnostic precision. These tools are changing how we assess tissue architecture, identify aggressive disease, and even rethink how biopsies are performed.

Micro-ultrasound, operating at 29 MHz, offers up to 300% higher resolution than conventional TRUS. The real-time visualization it provides is detailed enough to detect subtle architectural changes that MRI might miss. With the PRI-MUS scoring system (Prostate Risk Identification using Micro-Ultrasound), clinicians now have a structured way to risk-stratify lesions without leaving the ultrasound suite.

Meanwhile, shear wave elastography (SWE) is providing functional insight beyond what grayscale can offer. By measuring tissue stiffness, SWE can help us differentiate between benign and malignant areas, especially in the transition zone where conventional imaging often falls short. Have you considered how much additional value elastography could bring to your routine prostate assessments?

The evolving role of contrast-enhanced ultrasound (CEUS) is also noteworthy. With microbubble technology enhancing vascular detail, CEUS is proving useful in targeting suspicious areas. In some cases, it even outperforms MRI in patients with contraindications to gadolinium. Is there a place for CEUS in your practice?

And what about biopsies? While MRI fusion-guided approaches have become popular, micro-ultrasound offers a compelling, MRI-independent alternative. In experienced hands, it may not only match MRI-targeted biopsy accuracy but even outperform it in certain clinical contexts. Could this be the moment to reassess your default workflow?

Across the globe, clinicians are rethinking prostate imaging protocols. In settings where MRI is limited or inaccessible, these advanced ultrasound techniques are not just stand-ins; they are front-line modalities in their own right. We should be teaching residents and sonographers to see prostate ultrasound as more than just a guided-needle pathway.

This isn’t just about technology. It’s about mindset. Are we giving prostate ultrasound the credit it deserves as a dynamic, diagnostic-first tool?

We invite you to reflect on your current practices. Are you leveraging all that modern ultrasound has to offer in prostate disease? Are there barriers—technical, educational, or institutional—that keep your department from integrating these advancements?

Let us know what you think. Share your experiences, your questions, your doubts. The conversation around prostate ultrasound is changing, and we want your thoughts.

Bruce R. Gilbert, MD, PhD, is a Professor of Urology at Zucker School of Medicine of Hofstra/Northwell, Vice-Chair for Urology Quality, and Director of Male Reproductive and Sexual Medicine at the Smith Institute for Urology in New York.

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6 Ultrasound Trends to Watch in 2025

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The field of ultrasound technology is rapidly evolving, with advances that promise to reshape diagnostic imaging and patient care. As we begin 2025, several exciting trends are emerging, driven by breakthroughs in artificial intelligence, portability, and precision imaging. Here, we explore six ultrasound trends that are set to make waves in the medical field in 2025.

1. AI-Powered Ultrasound Diagnostics

Artificial Intelligence (AI) is transforming ultrasound imaging by automating complex tasks and enhancing diagnostic accuracy. In 2025, we expect AI to play a central role in streamlining workflows.

AI algorithms are increasingly capable of analyzing ultrasound images to detect and measure abnormalities, such as tumors, cysts, or cardiovascular issues, with speed and precision. These systems can assist practitioners in diagnosing conditions at an earlier state, reducing the risk of misdiagnosis. Moreover, real-time AI guidance is being integrated into portable devices, making it easier for clinicians to perform and interpret scans in remote or underserved areas.

For example, machine learning models are being trained to help ultrasound practitioners evaluate fetal development, monitor chronic diseases, and even predict patient outcomes. As these tools become more accessible, AI-driven ultrasound diagnostics will help address global disparities in healthcare delivery.

2. Therapeutic Ultrasound

Beyond diagnostics, ultrasound is increasingly being used for therapeutic purposes. Therapeutic ultrasound employs high-intensity sound waves to treat a variety of medical conditions by delivering targeted energy to tissues.

Applications of therapeutic ultrasound include treating kidney stones, fibroid, and prostate disease, as well as enhancing drug delivery and alleviating chronic pain. Focused ultrasound therapy is also making significant strides in oncology. It’s used to ablate tumors non-invasively using either thermal or mechanical effects and the latter has been found to also promote abscopal immune responses. Additionally, this technology is showing promise in neurology, with research exploring its potential to treat conditions like Parkinson’s disease, addiction, and depression by stimulating specific areas of the brain.

As the technology continues to advance, therapeutic ultrasound offers a noninvasive alternative to traditional surgical procedures, reducing recovery times and minimizing risks. In 2025, look out for this application as it gains more widespread adoption in both clinical and research settings.

3. Miniaturization and Portability

Portability is becoming a common feature of next-generation ultrasound devices. Compact and lightweight handheld units are set to become even more powerful in 2025, enabling point-of-care imaging in ways that were unimaginable just a decade ago.

These miniaturized devices are equipped with wireless capabilities, allowing clinicians to transmit data seamlessly to cloud-based platforms or electronic health records (EHRs). In emergency situations, paramedics and first responders can use portable ultrasound to assess internal injuries on-site, significantly improving patient outcomes.

Additionally, this trend aligns with the growing focus on telemedicine. Patients in remote or rural areas can now benefit from real-time imaging performed by trained technologists and reviewed by specialists miles away.

4. High-Resolution 3D and 4D Imaging

The demand for high-resolution imaging is pushing the boundaries of 3D and 4D ultrasound technology. By 2025, these systems will deliver clearer, more detailed images, providing clinicians with enhanced diagnostic capabilities.

4D ultrasound, which adds the dimension of time to 3D imaging, is especially beneficial in fields like obstetrics, where it offers real-time visualization of fetal movements. Beyond obstetrics, high-resolution imaging is proving invaluable in cardiology and oncology, enabling practitioners to visualize complex structures such as heart valves or tumor margins with greater clarity. This technology also bridges the gap and allows for greater reliability of mutual registration between ultrasound and MRI, CT, and PET.  

Image resolution improvements are accompanied by generally more affordable ultrasound technology overall, making sonography a first radiologic assessment tool accessible to smaller clinics and facilities worldwide.

5. Integration With Wearable Technologies

Wearable devices are stepping into the ultrasound space, promising to revolutionize how and where imaging is conducted. These devices, which can be worn as patches or integrated into clothing, are designed to provide continuous monitoring of specific conditions.

In 2025, you may see wearable ultrasound being used for applications like tracking cardiovascular health or monitoring chronic conditions such as kidney disease. For instance, a wearable device could continuously measure blood flow or detect abnormalities in real time, alerting healthcare providers to intervene in a timely manner.

This trend aligns with the broader movement towards personalized medicine, where patients take a proactive role in their healthcare with the help of smart technologies.

6. Expanded Use of Contrast-Enhanced Ultrasound (CEUS)

Contrast-enhanced ultrasound (CEUS) is gaining traction for its ability to improve visualization of blood flow and tissue vascularity. Unlike traditional ultrasound, CEUS uses microbubble contrast agents that provide detailed imaging without exposing patients to ionizing radiation or iodinated contrast material.

In 2025, CEUS is expected to find broader applications, particularly in oncology and cardiology. It is being used to assess heart function more accurately, differentiate between benign and malignant lesions, monitor the efficacy of cancer treatments, and has therapeutic applications. The latter is a unique demonstration of ultrasound having both diagnostic and therapeutic indications. 

The noninvasive nature of CEUS, combined with its diagnostic precision, is making it a preferred option for patients and providers alike. As regulatory approvals expand and more clinicians are trained to use this technology, CEUS will likely become a standard in advanced diagnostic imaging.

Conclusion

Ultrasound technology is undergoing a renaissance, driven by advances in electronics, miniaturization, portability, and imaging algorithms, including AI. As we move into 2025, these trends are set to enhance diagnostic capabilities, improve patient outcomes, and make imaging more accessible than ever before.

For healthcare providers and institutions, staying ahead of these trends will be critical in delivering cutting-edge care. Whether through adopting AI-powered solutions or CEUS, integrating wearable devices, or exploring new techniques like therapeutic ultrasound, the future of ultrasound is brighter—and more innovative—than ever.

Therese Cooper, BS, RDMS, is a sonographer and the Chief Learning Officer at the American Institute of Ultrasound in Medicine.

The Next Frontiers of Intestinal Ultrasound for the Assessment of Inflammatory Bowel Disease (IBD): CEUS, SICUS, and Elastography

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In recent years, the utility of intestinal ultrasound (IUS) in diagnosing and managing inflammatory bowel disease (IBD) has gained substantial momentum. The Scan featured a blog post in June 2024 describing the features and uses of IUS for diagnosing and monitoring IBD. That previous article highlighted the many features that can be monitored to assess IBD disease activity and severity right at the bedside using B-mode ultrasound, highlighting that bowel wall thickness (BWT), Doppler signaling (hyperemia), loss of stratification of bowel wall layers (BWS), and peri-intestinal hyperechoic fat are important features of inflammatory on IUS.1 However, adjunct techniques, such as using contrast with ultrasound, may permit better detection of disease complications and activity, particularly in Crohn’s disease, where patients are at risk of developing intestinal strictures (narrowing), bowel perforation, and abscesses. Indeed, these advanced ultrasound techniques push the boundaries of what noninvasive imaging can offer. This blog post delves into three promising techniques—contrast-enhanced ultrasound (CEUS), small intestinal contrast-enhanced ultrasound (SICUS), and elastography—each providing new dimensions to our understanding of IBD and its management.

Contrast-Enhanced Ultrasound (CEUS): Adding Depth to Vascular Assessment

CEUS represents a significant advancement in IUS, particularly in assessing disease activity and vascularization. By injecting a contrast composed of gas-filled microbubbles stabilized by a lipid capsule into the bloodstream, CEUS enhances the visualization of bowel wall vascularity, which is a key indicator of inflammation in IBD. The evaluation relies on the dynamic assessment of the contrast uptake in areas with increased vascular activities, whose intensity can change over time.2 Although visual evaluation can demonstrate areas of activities on CEUS, advanced software is also used to generate time-intensity curves, which measure the signal intensity from the first bubble arrival in the bowel segment of interest and progressive decline in intensity (wash-out) usually over 2 minutes of image capture.3

CEUS can be used in various clinical contexts to monitor Crohn’s disease. The time-intensity curves generated by CEUS are used to calculate the signal’s peak intensity and area under the curve (AUC). Wilkens et al demonstrated that peak intensity and AUC are increased in patients with active disease as compared to controls.4 Further studies have demonstrated promising results in differentiating Crohn’s disease lesions with active inflammation instead of lesions composed predominantly of fibrostenotic tissue.5 Variations in outcomes may be related to the type of contrast used, the quantitative CEUS value of interest analyzed, and the variability in the ultrasound system and analysis software used, which are not standardized between systems.5 However, such findings may be important in predicting response to therapy instead of prioritizing surgical options, as limited data demonstrated higher inflammation quantified by CEUS had a higher response rate to therapies.6

CEUS has emerged as a valuable tool in monitoring complications of Crohn’s disease (CD), particularly in assessing the presence and extent of fistulas and abscesses. By enhancing the visibility of vascular structures and inflammatory activity, CEUS allows for the precise identification and measurement of these complications, which can be challenging to characterize with conventional imaging methods. This enhanced visualization is crucial for guiding clinical decisions, including the need for surgical intervention or adjustments in medical therapy.7

Small Intestinal Oral Contrast-Enhanced Ultrasound (SICUS): Expanding the Reach of IUS

While CEUS focuses on enhancing vascular imaging, SICUS takes a different approach by improving the visualization of the small intestine, an area notoriously difficult to image using traditional ultrasound techniques. SICUS is performed in the fasted state and involves the oral administration of a non-absorbable contrast medium, generally a polyethylene glycol solution, that distends the small bowel loops, allowing for better visualization of the bowel wall and lumen. The exam may last 30 to 45 minutes for the contrast to arrive at the areas of interest.8

This technique is particularly valuable in the assessment of small bowel CD, where skip lesions and strictures can be challenging to detect and characterize. SICUS enhances the delineation of these abnormalities, providing a clearer picture of the disease’s extent and severity. Moreover, SICUS can be employed alongside B-mode and CEUS to offer a comprehensive assessment of the small intestine. The combined use of these modalities allows for a more nuanced evaluation of both the inflammatory and structural components of the disease, leading to more informed treatment strategies.9

Elastography: A Noninvasive Window Into Fibrosis

One of the most challenging aspects of managing IBD is differentiating between inflammation and fibrosis, particularly in chronic CD, where long-standing inflammation can lead to fibrotic changes in the bowel wall. Elastography, a technique that measures tissue stiffness, is a promising solution to this issue. By applying mechanical waves to the tissue and measuring the speed at which they propagate, elastography can provide a quantitative assessment of bowel wall stiffness—a surrogate marker for fibrosis.5 Again, this is essential in predicting lesions that would be amendable to medical therapy as opposed to surgery. However, challenges exist in the assessment of the bowel using this technique, as measurements can be affected by peristalsis, and a large body habitus can impede the penetration of the sound waves. Values are not yet standardized between ultrasound systems, making the validation of specific thresholds difficult between centers.5 As research continues to validate its accuracy and reliability, elastography may become a standard tool in the long-term management of IBD.

The Future of IUS in IBD Management

The integration of CEUS, SICUS, and elastography into the IUS toolkit marks a significant step forward in the management of IBD. These advanced techniques not only enhance our ability to diagnose and monitor the disease but also provide critical insights that can tailor treatment strategies to the individual patient.

As we continue to refine these methods and validate their use in clinical practice, the future of IUS in IBD management looks promising. The ability to assess the disease’s inflammatory and fibrotic components in real-time, noninvasively, and with high accuracy will undoubtedly improve patient outcomes and quality of life. However, to move toward more widespread adoption, more training in these techniques will be necessary, and further validation of the data generated is warranted.

In conclusion, the advancements in IUS, particularly with the advent of CEUS, SICUS, and elastography, are poised to transform the landscape of IBD management. These techniques offer a more detailed and nuanced understanding of the disease, enabling us to make more informed decisions that ultimately benefit our patients. As we look to the future, the continued evolution of IUS will undoubtedly play a pivotal role in the quest for better outcomes in IBD care.

Mallory Chavannes, MD, MHSc, FRCPC, FAAP, is an Assistant Professor of Pediatrics in the Division of Gastroenterology, Hepatology, & Nutrition, and is Medical Director of the Inflammatory Bowel Disease Program, at Children’s Hospital Los Angeles.

References:

  1. Novak KL, Nylund K, Maaser C, et al. Expert consensus on optimal acquisition and development of the international bowel ultrasound segmental activity score [IBUS-SAS]: a reliability and inter-rater variability study on intestinal ultrasonography in Crohn’s disease. J Crohns Colitis 2021; 15:609–616. doi: 10.1093/ecco-jcc/jjaa216. PMID: 33098642; PMCID: PMC8023841.
  2. Pecere S, Holleran G, Ainora ME, et al. Usefulness of contrast-enhanced ultrasound (CEUS) in inflammatory bowel disease (IBD). Dig Liver Dis 2018; 50:761–767. doi: 10.1016/j.dld.2018.03.023. Epub 2018 Apr 3. PMID: 29705029.
  3. Merrill C, Wilson SR. Ultrasound of the bowel with a focus on IBD: the new best practice [published online ahead of print August 14, 2024]. Abdom Radiol (NY) doi: 10.1007/s00261-024-04496-1. PMID: 39141152.
  4. Wilkens R, Wilson A, Burns PN, Ghosh S, Wilson SR. Persistent enhancement on contrast-enhanced ultrasound studies of severe Crohn’s disease: stuck bubbles? Ultrasound Med Biol 2018; 44:2189–2198. doi: 10.1016/j.ultrasmedbio.2018.06.018. PMID: 30076030.
  5. Coelho R, Ribeiro H, Maconi G. Bowel thickening in Crohn’s disease: fibrosis or inflammation? Diagnostic ultrasound imaging tools. Inflamm Bowel Dis 2017; 23:23–34. doi: 10.1097/MIB.0000000000000997. PMID: 28002125.
  6. Quaia E, Gennari AG, Cova MA, van Beek EJR. Differentiation of inflammatory from fibrotic ileal strictures among patients with Crohn’s disease based on visual analysis: feasibility study combining conventional B-mode ultrasound, contrast-enhanced ultrasound and strain elastography. Ultrasound Med Biol 2018; 44:762–770. doi: 10.1016/j.ultrasmedbio.2017.11.015. PMID: 29331357.
  7. Pecere S, Holleran G, Ainora ME, et al. Usefulness of contrast-enhanced ultrasound (CEUS) in inflammatory bowel disease (IBD). Dig Liver Dis 2018; 50:761–767. doi: 10.1016/j.dld.2018.03.023. PMID: 29705029.
  8. Losurdo G, De Bellis M, Rima R, et al. Small intestinal contrast ultrasonography (SICUS) in Crohn’s disease: systematic review and meta-analysis. J Clin Med 2023; 12(24):7714. doi: 10.3390/jcm12247714. PMID: 38137782; PMCID: PMC10744114.

Mocci G, Migaleddu V, Cabras F, et al. SICUS and CEUS imaging in Crohn’s disease: an update. J Ultrasound 2017; 20:1–9. doi: 10.1007/s40477-016-0230-5. PMID: 28298939; PMCID: PMC5334271.

How Can Ultrasound Contrast Agents Be Used to Sensitize Tumors to Radiation?

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Ultrasound contrast agents (UCAs) have the ability to go throughout the body and reach anywhere there is active vascularity. As clinicians and scientists, we use this to our advantage for diagnostic and therapeutic purposes. A unique characteristic of a UCA is its ability to generate nonlinear responses at sufficient pressure. These nonlinear responses produce harmonics in an acoustic field. UCAs undergo natural oscillations, and, at higher pressures, these UCAs can produce bioeffects. Inertial cavitation is the transient destruction of UCAs from increased pressure, while stable cavitation is a constant oscillation. Both of these cavitation states can produce shear stress on vessel walls, particularly endothelial cells.

Endothelial cells are the cell layer that lines all blood vessels in the body and are responsible for many functions but primarily control the passage of nutrients into tissues.1 In normal tissue, endothelial cells are uniform and form an organized monolayer network with tight junction connections.1 However, in tumor endothelial cells (TECs), it is much more of a chaotic process. In TECs, long, fragile cytoplasmic projections extend into the vessel lumen, creating small openings and gaps in the vessel wall.1 In addition to smaller gaps, larger openings (up to 1.5 µm) have also been identified, which make cell closures more difficult. These small and large gaps in TECs can be harnessed to produce endothelial cell apoptosis by destroying UCAs via inertial cavitation. Utilizing inertial cavitation has been shown to produce endothelial cell apoptosis (cell death) by generating bioeffects (ie, shock waves, microjets, micro streams, and thermal effects) that mechanically perturb TEC membranes.

Moreover, there are many components to a cell membrane, which goes beyond the scope of this blog post; however, sphingolipids are an essential enzyme to a cell membrane.2 Sphingolipids help maintain cellular homeostasis and are closely associated with cellular biologic functions, such as proliferation, apoptosis, or oxidative stress on endothelial cells.2 Some sphingolipids, such as ceramide, are important second signaling molecules that determine cell proliferation or death.

Traditionally, radiation therapy has been thought to act by damaging the DNA of cells via double and single DNA strand breaks, resulting in apoptosis. However, more recent studies have suggested that blood vessels are the determining factor of tumor response to radiation therapy at high doses (>8–19 Gy).3 Endothelial cells exposed to high doses of radiation upregulate the acid-sphingomyelinase pathway (ASMASE), which hydrolyzes sphingomyelin (dominant sphingolipid) into apoptosis, with ceramide acting as the second messenger. El Kaffas et al suggest that a primary factor why endothelial cells respond differently than other cell types is because endothelial cells have a 20x enrichment of a nonlyosomal secretory form of the ASMASE enzyme.4,5 This enzyme is associated with membrane remodeling, restructuring, responses to shear stress, and activation of ceramide from cell stressors.6,7 Additionally, endothelial cells are more sensitive to shear stress and mechanical forces.4 Radiation therapy and inertial cavitation treatments separately have been shown to produce tumor cell death. Combining these two treatments results in an increased accumulation of ceramide production and apoptosis, leading to improved tumor radiosensitivity.

Over the past decade, primarily in pre-clinical research, the benefits of combining microbubbles and radiation have been shown. From one of the original pre-clinical studies validating this concept, Czarnota et al showed that inertial cavitation and radiation therapy in a human prostate xenograft model in mice led to a 10-fold increase in ceramide-related endothelial cell death, confirming the benefits of the combined relationship.7 In addition, the study demonstrated a significant effect with a decreased radiotherapy dose (2 Gy versus 8 Gy) when combined with inertial cavitation compared to stand-alone treatment regimens. This mechanism has mainly been validated with in vivo studies. However, my group at Thomas Jefferson University has a first-ever pilot clinical trial incorporating ultrasound-triggered microbubble destruction (UTMD) to sensitize hepatocellular carcinoma in patients that receive the locoregional therapy, trans-arterial radioembolization (TARE).8 In an interim analysis, there was a greater prevalence of tumor response in the patients receiving TARE plus UTMD as opposed to in those who received TARE alone. Additionally, lab values and liver function tests demonstrated no significant differences between study groups, indicating that adding microbubble cavitation does not affect patient safety or liver functions.

This study is an ongoing clinical trial and will complete enrollment within the next 6 months, and this concept has been incorporated in non-HCC tumors in an ongoing pilot clinical trial at Thomas Jefferson University (NCT# 03199274). As a result of our research to date, we have learned that incorporating UTMD with radiation therapy may help sensitize tumors for improved survival and treatment outcomes. Additional clinical research is needed in this field because the combination treatment regimen may be easily incorporated into non-liver tumors.

References

  1. Dudley AC. Tumor endothelial cells. Cold Spring Harb Perspect Med 2012; 2:a006536. doi: 10.1101/cshperspect.a006536.
  2. Lai Y, Tian Y, You X, Du J, Huang J. Effects of sphingolipid metabolism disorders on endothelial cells. Lipids Health Dis 2022: 21(1):101. doi: 10.1186/s12944-022-01701-2.
  3. Paris F et al. Endothelial apoptosis as the primary lesion initiating intestinal radiation damage in mice. Science 2001; 293(5528):293–297. doi: 10.1126/science.1060191.
  4. El Kaffas A and Czarnota GJ. Biomechanical effects of microbubbles: from radiosensitization to cell death. Future Oncol 2015; 11(7):1093–1108. doi: 10.2217/fon.15.19.
  5. Tabas I. Secretory sphingomyelinase. Chem Phys Lipids 1999; 102(1):123–130. doi: 10.1016/S0009-3084(99)00080-8.
  6. El Kaffas A, Al-Mahrouki A, Hashim A, Law N, Giles A, Czarnota GJ. Role of acid sphingomyelinase and ceramide in mechano-acoustic enhancement of tumor radiation responses. J Natl Cancer Inst 2018; 110(9):1009–1018. doi: 10.1093/jnci/djy011.
  7. Czarnota GJ et al. Tumor radiation response enhancement by acoustical stimulation of the vasculature. Proc Natl Acad Sci U S A  2012; 109(30): E2033-E2041. doi: 10.1073/pnas.1200053109.
  8. Eisenbrey JR et al. US-triggered microbubble destruction for augmenting hepatocellular carcinoma response to transarterial radioembolization: a randomized pilot clinical trial. Radiology 2021; 298:450–457. doi: 10.1148/radiol.2020202321.

Corinne Wessner, MS, MBA, RDMS, RVT, is a research sonographer at Thomas Jefferson University and a PhD candidate at Drexel University in the School of Biomedical Engineering, Science and Health Systems in Philadelphia, PA. She is also Vice Chair of the American Institute of Ultrasound in Medicine’s (AIUM’s) High-Frequency Clinical and Preclinical Imaging Community (2023–2025).

Interested in reading more from Corinne Wessner? Check out these articles from the Journal of Ultrasound in Medicine (JUM). Members of AIUM can access them for free after logging in to the AIUM. Join the AIUM today!):

Lymphosonography: The use of contrast-enhanced ultrasound as a lymphatic mapping technique

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Ipsilateral axillary diagnostic ultrasound is part of the initial staging for breast cancer to evaluate lymph nodes using a b-mode classification where certain aspects, when present, increase the level of suspicion for metastatic disease, such as cortical thickening and poor hilar visibility.1–3 Diagnostic ultrasound is also used as a method to guide biopsies of the suspicious lymph nodes.1

The majority of patients will have no suspicious lymph nodes findings at the time of diagnosis, the lymphatic system mapping after the injection of blue dye and/or a radioactive tracer followed by a surgical excision becomes the only way to determine the final stage of disease. However, these methods have limitations such as the use of radiation and lack of an imaging component.

In the past, ultrasound could not be used for lymphatic mapping, since mapping requires administration of a tracer. This changed with the use of contrast-enhanced ultrasound (CEUS) to detect lymph nodes after subcutaneous injections of microbubble-based ultrasound contrast agents (UCA), termed “lymphosonography”.4–6 The development of the lymphosonography technique addressed the limitations of the currently used lymphatic mapping techniques.

Our group conducted a clinical trial to evaluate the efficacy of CEUS lymphosonography in the identification of sentinel lymph nodes (SLN) in patients with breast cancer undergoing surgical excision following the injection of blue dye and radioactive tracer as part of their standard of care using pathology results for malignancy as a reference standard.6,7

In the clinical trial, 86 subjects were enrolled and 79 completed the study. The subjects received 4 subcutaneous injections of ultrasound contrast agent around the tumor, for a total of 1.0 ml. A clinical ultrasound scanner with CEUS capabilities was used to identify SLNs. After the ultrasound study examination, the subjects received blue dye and radioactive tracer for guiding SLN excision as part of their standard of care. The SLNs excised during the standard-of-care surgical excision were classified as positive or negative for presence of blue dye, radioactive tracer and UCA, and sent for pathology to determine presence or absence of metastatic involvement.

Example of a sentinel lymph node (SLN) seen with lymphosonography. The arrow indicates the SLN. The arrowhead indicates the lymphatic channel.

A total of 252 SLNs were excised from the 79 subjects. Of the 252 SLNs excised, 158 were positive for blue dye, 222 were positive for radioactive tracer and 223 were positive for UCA. Statistical comparison showed that compared with the reference standards, lymphosonography showed similar accuracy with radioactive tracer (p > 0.15) and higher accuracy (p < 0.0001). The pathology results showed that, of the 252 SLNs excised, 34 had metastatic involvement and were determined malignant by pathology. Of these 34 SLNs, 18 were positive for blue dye (detection rate of 53%), 23 were positive for radioactive tracer (detection rate of 68%) and 34 were positive for UCA (detection rate of 100%; p < 0.0001).

The conclusion of this study indicates that lymphosonography had similar accuracy as the standard-of-care methods for identifying SLNs in breast cancer patients, with the added advantage of an imaging component that allows for a preoperative evaluation of SLNs and that lymphosonography may be a more specific and precise approach to SLN identification in patients with breast cancer.6

Larger multicenter clinical trials are necessary to be able to translate this technique to the clinical setting and to be able to incorporate it as part of the breast cancer patients’ standard of care.

  1. Voit CA, van Akkooi ACJ, Schäfer-Hesterberg G, et al. Rotterdam Criteria for sentinel node (SN) tumor burden and the accuracy of ultrasound (US)-guided fine-needle aspiration cytology (FNAC): can US-guided FNAC replace SN staging in patients with melanoma? J Clinical Oncol 2009; 27(30):4994–5000.
  2. Dialani V, Dogan B, Dodelzon K, Dontchos BN, Modi N, Grimm L. Axillary imaging following a new invasive breast cancer diagnosis—A radiologist’s dilemma. J Breast Imaging 2021; 3:645–658.
  3. Chang JM, Leung JWT, Moy L, Ha SM, Moon WK. Axillary nodal evaluation in breast cancer: state of the art. Radiology 2020; 295:500–515.
  4. Goldberg BB, Merton DA, Liu J-B, Thakur M, et al. Sentinel lymph nodes in a swine model with melanoma: contrast-enhanced lymphatic US. Radiology 2004; 230:727–734.
  5. Goldberg BB, Merton DA, Liu J-B, Murphy G, Forsberg F. Contrast‐enhanced sonographic imaging of lymphatic channels and sentinel lymph nodes. J Ultrasound Med 2005; 24:953–965. doi: 10.7863/jum.2005.24.7.953.
  6. Machado P, Liu J-B, Needleman L, et al. Sentinel lymph node identification in patients with breast cancer using lymphosonography. Ultrasound Med Biol 2023; 49:616–625. Epub 2022 Nov 26.
  7. Machado P, Liu JB, Needleman L, et al. Sentinel lymph node identification in post neoadjuvant chemotherapy breast cancer patients undergoing surgical excision using lymphosonography. J Ultrasound Med 2023; 42:1509–1517. doi: 10.1002/jum.16164. Epub 2023 Jan 2.

Priscilla Machado, MD, FAIUM, is a Research Assistant Professor in the Department of Radiology at Thomas Jefferson University in Philadelphia, PA.

Interested in learning more about ultrasound? Check out these posts from the Scan:

One More Reason to Advocate for Contrast-Enhanced Ultrasound in Children: No Current Shortage of Ultrasound Contrast Agents

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Contrast-enhanced ultrasound (CEUS) is a valuable tool to evaluate the pediatric patient as it offers many of the diagnostic benefits of other imaging modalities such as CT or MRI but avoids potential risks including radiation exposure and sedation. Furthermore, CEUS is portable and can be performed at the patient’s bedside, which is particularly important in critically ill children where transportation to the radiology department may be difficult. Currently, in the United States, only one ultrasound contrast agent is FDA-approved for use in pediatric patients for intravesical use for contrast-enhanced voiding urosonography (ceVUS) and for intravenous use for characterization of liver lesions and cardiac indications. However, off-label use has greatly expanded the applications of this technology to the betterment of patients.

Grayscale (left) and contrast-enhanced (right) ultrasound of the left kidney in a 3-year-old boy incidentally found to have a renal lesion on prior spine MRI. Images demonstrate a predominately cystic complex lesion (circle). On contrast-enhanced images, the cystic components are clearly demonstrated with faint enhancement of thin septations allowing characterization of the lesion as a minimally complex renal cyst (Bosniak type 2F). Normal diffuse homogenous enhancement is seen in the remainder of the left renal parenchyma (arrows). In this case, the use of contrast-enhanced ultrasound for lesion characterization prevented radiation exposure, which would be required for CT, and sedation, which would be required for MRI.

Multiple studies have shown the feasibility and value of CEUS in a wide variety of applications including evaluation of the neonatal brain in hypoxic-ischemic injury, intraoperative characterization of brain lesions for real-time assessment of resection margins, initial and follow-up evaluations in the setting of solid abdominal organ trauma, quantification of femoral head perfusion before and after developmental hip dysplasia reduction, and intraoperative ceVUS to visualize vesicoureteral reflux and assess the efficacy of bladder bulking agent injections and possible requirement for additional surgical procedures. This is to name just a few!

Additionally, CEUS has been utilized by Interventional Radiology departments in many troubleshooting situations including evaluation of vascular access/thrombosis, identifying solid tumor components for biopsy, visualizing non-solid abscess contents for accurate drain placement, and lymph node injection for evaluation of the lymphatic drainage pathways. Again, this is a limited list of uses! Essentially, any diagnostic or therapeutic situation that would benefit from real-time bedside evaluation of organs, lesions, vessels (or anything in the human body) could potentially benefit from CEUS.

Despite the widespread applications of CEUS, few centers regularly employ this technique or only use it in select cases. Concerns about contrast agent side effects, including anaphylaxis, have been consistently demonstrated to be minimal and lower than other contrast agents routinely utilized in imaging studies and the safety of ultrasound contrast agents has been continually proven over time. While appropriate monitoring and preparation for severe reactions is mandatory, this is not dissimilar to safety practices with CT and MRI contrast agents. Speaking of which, current CT contrast shortages and uncertain implications of gadolinium deposition with MRI contrast agents further bolster support for using CEUS as a first-line imaging modality.

Even after explaining the relatively high benefit-to-risk ratio in this patient population, advocates for CEUS continue to find resistance to broader use. Some obstacles to wider implementation include staff training and requirement of a radiologist during the CEUS, which is currently standard practice. Select institutions offer CEUS training courses for technologists and physicians to familiarize them with technique and workflow management. Like any new procedure, education, experience, and departmental support allow increasing confidence and ease of implementation. Despite adequate technologist and nursing staff familiarity, in this time of ever-growing imaging study volumes and hospital staffing shortages, requiring the physical attendance of a radiologist for a CEUS examination is less than ideal. However, this allows valuable support for the technologist and for the radiologist to communicate directly with the patient and family providing an immeasurable face-to-face interaction that cannot be replicated in the reading room.

To summarize, CEUS is an incredibly valuable tool in evaluating children with vast clinical applications, the list of which continues to grow over time. If you have a patient and ask yourself “could CEUS add information with high benefit-to-risk ratio,” the answer is often “yes.” But lack of widespread awareness and implementation lead to clinicians never asking that question or even considering the potential benefit of CEUS in pediatric patients. A growing community of Pediatric Diagnostic and Interventional Radiologists would like to change that in the future.

If you are using CEUS at your institution, what kind of scenarios (standard and unique) have you found CEUS to be helpful? If you are not using CEUS at your institution, what do you see as current obstacles? What would be required or helpful for you to implement in your practice?

Ryne Didier, MD, is a Pediatric Radiologist at the Children’s Hospital of Philadelphia (@CHOPRadiology). Her clinical and research interests include prenatal imaging and emerging ultrasound imaging techniques and applications.

Interested in learning more about pediatric ultrasound? Check out the following posts from the Scan:

Is it Nuts to Think About Sparing the Testicles?

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The testi-monial

On my ultrasound list today, patient X, returning for a follow-up, was recounting his ‘close shave’ from losing one of his testicles after a suspected lump was detected during an ultrasound examination at his local hospital when he had pain in the scrotum. He was initially listed for theatre for an orchiectomy and the patient was grateful that someone stopped that and referred him to us for a repeat scan, this time with an adjunct contrast-enhanced ultrasound, which showed the abnormality in his testicle was an infarct instead of a tumor (Figure 1), which improved on follow-up (Figure 2).

Figure 1: Grayscale (left) and contrast-enhanced ultrasound (right) of patient X’s right testicular focal abnormality. Contrast-enhanced ultrasound showed no enhancement within the abnormality.
Figure 2: On follow-up contrast-enhanced ultrasound, it reduced in size and again showed no enhancement, supporting the diagnosis of a resolving infarct.

Incidentally detected testicular focal abnormality inevitably generates a great amount of anxiety, both for patients and doctors involved.

Why?

Ultrasound is good at picking up lesions. The problem is that, often, we do not know what they are, or what to do with them. While the old surgical dogma of ‘if in doubt, take it out’ does a good job in dealing with the uncertainty, it does appear to be an overly aggressive anxiety-relieving strategy, and not without consequence, as orchiectomy comes with associated endocrine, reproductive, and psychological impact.

It is worth noting that this problem is further exacerbated by the increased use of ultrasound for a variety of indications, which led to an increasing number of incidentally detected small focal testicular lesions. Many incidentally detected lesions are benign.

Even with the most beneficial of intentions, is scrotal ultrasound causing harm?

What could we do?

Which test tickles your fancy?

Although a variety of tools have been at the clinician’s disposal, the preoperative diagnoses of testicular masses remain uncertain in many cases. Tumor markers are often not raised in patients with malignant testicular tumors. MRI is considered a second-line tool for the characterization of focal testicular lesions; high cost, long study time, lack of standardization, and expertise are some of the drawbacks.

In most cases, ultrasound remains the primary diagnostic test to facilitate decision-making. Lack of flow on color Doppler (CD) increases the probability of a benign lesion but must be interpreted with caution as a substantial proportion of malignant lesions show no detectible vascularity.1 Microflow techniques may increase sensitivity,2 but the evidence is lacking for its value in assessing small testicular lesions. Imaging with contrast-enhanced ultrasound (CEUS) and elastography provides additional information.3,4 CEUS is a particularly valuable technique. The unique value of CEUS is the unequivocal demonstration of the lack of vascularity likely to be encountered in benign lesions, such as an infarct,5 hematoma,6 or epidermoid cyst,7 allowing for “watchful waiting” with ultrasound.8 Contrast dynamics may help differentiate benign from malignant solid masses, but this technique is not yet sufficiently robust for routine clinical use.9 Strain elastography could potentially identify the “hard” lesion as more likely malignant and the “soft” lesion benign on strain elastography.10 Shear-wave elastography has been less extensively evaluated but may also show differences between benign and malignant testicular lesions.11

I am not advocating that these ultrasound techniques are entirely diagnostic, but I am certainly suggesting that when combined with clinical and laboratory information, ultrasound technology is available for a more accurate assessment of the risk of malignancy. This may facilitate more desirable testis-sparing management options, such as ultrasound surveillance or testis-sparing surgery (TSS), to be considered, and avoid unnecessary orchidectomies.  

It is not nuts to suggest sparing the testicles.

The ball’s in your court.

References

  1. Ma W, Sarasohn D, Zheng J, Vargas HA, Bach A. Causes of avascular hypoechoic testicular lesions detected at scrotal ultrasound: can they be considered benign? Am J Roentgenology 2017; 209:110–115.
  2. Lee YS, Kim MJ, Han SW, et al. Superb microvascular imaging for the detection of parenchymal perfusion in normal and undescended testes in young children. Eur J Radiol 2016; 85:649–656.
  3. Huang DY, Sidhu PS. Focal testicular lesions: colour Doppler ultrasound, contrast-enhanced ultrasound and tissue elastography as adjuvants to the diagnosis. Br J Radiol 2012; 85 Spec No 1:S41–S53.
  4. Huang DY, Pesapane F, Rafailidis V, et al. The role of multiparametric ultrasound in the diagnosis of paediatric scrotal pathology. Br J Radiol 2020; 93(1110):20200063.
  5. Zebari S, Huang DY, Wilkins CJ, Sidhu PS. Acute testicular segmental infarct following endovascular repair of a juxta-renal abdominal aortic aneurysm: case report and literature review. Urology 2019; 126:5–9.
  6. Yusuf GT, Rafailidis V, Moore S, et al. The role of contrast-enhanced ultrasound (CEUS) in the evaluation of scrotal trauma: a review. Insights Imaging 2020; 11:68.
  7. Patel K, Sellars ME, Clarke JL, Sidhu PS. Features of testicular epidermoid cysts on contrast-enhanced sonography and real-time tissue elastography. J Ultrasound Med 2012; 31:115–122.
  8. Shah A, Lung PF, Clarke JL, Sellars ME, Sidhu PS. Re: New ultrasound techniques for imaging of the indeterminate testicular lesion may avoid surgery completely. Clin Radiol 2010; 65:496–497.
  9. Pinto SPS, Huang DY, Dinesh AA, Sidhu PS, Ahmed K. A systematic review on the use of qualitative and quantitative contrast-enhanced ultrasound in diagnosing testicular abnormalities. Urology 2021; 154:16–23.
  10. Fang C, Huang DY, Sidhu PS. Elastography of focal testicular lesions: current concepts and utility. Ultrasonography 2019; 38:302–310.

Roy C, de Marini P, Labani A, Leyendecker P, Ohana M. Shear-wave elastography of the testicle: potential role of the stiffness value in various common testicular diseases. Clin Radiol 2020; 75:560 e9–e17.

Dr. Dean Huang, FRCR, EBIR, MD(Res), is a radiologist and the clinical lead of uroradiolgy at King’s College Hospital, London, UK. He completed his doctoral research on the clinical application of contrast-enhanced ultrasound for scrotal pathologies at King’s College London, UK.

Tweet him @DrDean_Huang

Interested in learning more about contrast-enhanced ultrasound? Check out the following posts from the Scan:

A Quick Introduction to Subharmonic Imaging and Pressure Estimation

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Our imaging field has had access to commercial microbubble-based ultrasound contrast agents for well over twenty years by now. It is well established that these agents—combined with nonlinear contrast-specific imaging techniques—improve both the sensitivity and specificity of ultrasound diagnoses across a wide range of clinical applications.

There are currently 3 ultrasound contrast agents approved by the United States’ Food and Drug Administration (FDA) for cardiology and/or radiology applications: Optison (GE Healthcare, Princeton, NJ); Definity (Lantheus Medical Imaging, N Billerica, MA); and Lumason (marketed for more than a decade in Europe and elsewhere as SonoVue; Bracco Imaging, Milan, Italy). There are other contrast agents in commercial development around the world; in particular Sonazoid (GE Healthcare) and BR55 (Bracco Imaging). Very importantly, the safety profiles of all of these agents are also well established with a severe reaction rate of less than 0.01% (based on studies of millions of dosages injected worldwide), making them the safest of all contrast media used for imaging.

Flemming Forsberg, PhD

Ultrasound agents consist of billions of gas microbubbles (typically < 8 mm in diameter) that are each encapsulated by an outer shell for stability. Following an intravenous injection, the microbubbles can traverse the lung capillaries and circulate in the blood for 3–6 minutes (under continuous imaging—longer if intermittent imaging is employed), due to their size and the higher molecular weight gasses used as filling gasses (rather than just air as was used in earlier microbubble designs), which reduces diffusion back into solution.

The acoustic properties of the bubble filing gasses (specifically the compressibility) are very different from those of the surrounding blood (by six orders of magnitude). Hence, microbubble-based ultrasound contrast agents can enhance ultrasound signals markedly with echo signals being increased by up to 30 dB. This in turn enables signals from breast tumor neovascularity corresponding mainly to vessels 20–39 mm in diameter to be imaged.

Ultrasound contrast agents not only enhance the backscattered ultrasound signals, but at sufficient acoustic pressures (typically above 0.3 MPa) they also act as nonlinear oscillators. These oscillations generate significant energy components in the received echo signals, which span the range of possible frequency emissions from subharmonics through ultra-harmonic frequency components. These nonlinear bubble echoes can be separated from tissue echoes and used to create contrast-sensitive imaging modalities such as harmonic imaging (HI), which is commercially available on most state-of-the-art ultrasound scanners.

Multi-pulse imaging strategies, such as pulse-inversion imaging or pulse-amplitude modulation, can further improve the depiction of microvascularity compared to color Doppler imaging modes. However, HI suffers from reduced blood-to-tissue contrast resulting from second harmonic generation and accumulation in tissue. Hence, subharmonic imaging (SHI), transmitting at the fundamental frequency (f0) and receiving at the subharmonic (f0/2), becomes an attractive alternative because of the weaker subharmonic generation in tissue and the significant subharmonic scattering produced by some new contrast agents. Several ultrasound scanners (from GE Healthcare and Mindray) have now been released with commercial SHI software packages. A recent multi-center study of 3D SHI for characterizing suspicious breast lesions indicates that diagnostic accuracies up to 97% can be achieved.

Ultrasound contrast agents can be used not only as vascular tracers but also as sensors for noninvasive pressure estimation by monitoring subharmonic contrast bubble amplitude variations. This innovative technique, called subharmonic-aided pressure estimation (SHAPE), relies on the inverse linear correlation (r2 > 0.90) between the amplitude of the subharmonic signals and hydrostatic pressure (up to 186 mmHg) measured in vitro for most (but not all) commercial contrast agents. SHAPE offers the possibility of allowing pressure gradients in the heart and throughout the cardiovascular system as well as interstitial fluid pressure in tumors to be obtained noninvasively. Studies indicate that SHAPE can provide in vivo pressure estimates with errors of less than 5 mmHg in the left and right ventricles of patients. Moreover, a large multi-center clinical trial of using SHAPE to diagnose clinically significant portal hypertension in 178 subjects resulted in a sensitivity of 91% and a specificity of 82% and these subjects had a higher SHAPE gradient than participants with lower pressures (0.27 ± 2.13 dB vs -5.34 ± 3.29 dB; p<0.001) indicating SHAPE may indeed be a useful tool for the diagnosis of portal hypertension.

Flemming Forsberg, PhD, FAIUM, FAIMBE, is a Professor of Radiology at Thomas Jefferson University in Philadelphia, Pennsylvania. He also serves as a Deputy Editor of the Journal of Ultrasound in Medicine and as the Vice Chair of the American Institute of Ultrasound in Medicine’s (AIUM’s) Contrast-Enhanced Ultrasound Community (2021–2023).

Interested in learning more about Contrast-Enhanced Ultrasound? Check out the following posts from the Scan:

Pediatric Contrast-Enhanced Voiding Urosonography Tips

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Contrast-enhanced voiding urosonography (ceVUS) is most commonly used to assess for vesicoureteral reflux (VUR) and anatomic abnormalities of the urethra. Like fluoroscopic voiding cystourethrography (VCUG) examinations, in ceVUS, contrast is administered into the urinary bladder, and images are obtained of the kidneys, ureters, bladder, and urethra during filling and voiding phases.

As a department, we have performed hundreds of ceVUS exams since we began clinical studies almost 7 years ago. I have learned to ask several questions before beginning each ceVUS to help the exam go smoothly.


Does the patient/family know what will happen during the ceVUS?

Ultrasound is a workhorse for pediatric imaging because of the inherent qualities of the modality: no ionizing radiation, patients in close proximity to family members, calm and darkened exam rooms, non-imposing equipment infrastructure, and (usually) the absence of sedation or anesthesia. Most of these attributes hold for ceVUS, but bladder catheterization changes the non-invasive use of US to an invasive examination. Even so, I have been amazed by the distances that families will travel to seek ceVUS in place of VCUG for their children.

Patient and family preparation is a vital first step for ceVUS. To best image the urethra and bladder base, the probe will be positioned on the lower abdomen, perineum, and over the genitals. Discussion of catheterization and probe positioning on the body in a manner appropriate for the child’s age is critical prior to beginning. Childlife specialists can help prepare the child and family as well as provide support and distraction techniques during the examination.

Right grade 3 vesicoureteral reflux in a 3-year-old girl. Sagittal dual display grayscale (on the left) and contrast mode (on the right) of the right kidney showing echogenic ultrasound contrast in the right renal collecting system with dilation of the renal pelvis and calyces.

How will the child void during the examination?

Prior to the voiding phase images during an examination on a young adult, the patient told us that she could not void in the supine position. Unprepared for that moment, we stretched the US unit power cord (and ourselves) to follow her into the adjoining restroom and image her kidneys while she sat on the commode.

A major benefit of ceVUS over VCUG is that the patient is not confined to voiding in a supine position when imaging with ultrasound. While a small percentage of children will not void during either a VCUG or ceVUS, making a plan for how they will void will set the patient up for success during the study. Absorbent pads, bedpans, urinals, training toddler seats, and full-size commodes are all options. When planned for, we often can still obtain urethral images while permitting the patient modesty through appropriate draping.

Which probe positions will be optimal for this patient?

Another benefit of ceVUS over VCUG is that the patient’s anatomy can be visualized even when there is no VUR. When obtaining pre-contrast images, you should start by determining the best window to visualize each kidney.

When VUR occurs, the kidney-ureter unit can be observed with probe positioning from the flank. This position may allow visualization of both the right and left refluxing unit in young children. A transperineal view may not only help to see the urethra but also the bladder base and ureteral insertions.

During VCUG, an imaging team may be accustomed to placing tape on the suprapubic region to secure the bladder catheter. However, US images cannot be obtained through tape. Anticipating the best view of the urethra will help avoid an inopportune tape placement, which will obscure visualization during voiding. In the bladder filling phase, the contrast is following through the catheter, which demarcates the entire course of the urethra. Practicing probe position from a suprapubic or transperineal window during bladder filling will help identify the best window to use when voiding begins. With these preliminaries in mind, we’ve had tremendous success with ceVUS at our institution.

Susan J. Back, MD, is a pediatric radiologist at Children’s Hospital of Philadelphia.

Interested in learning more about pediatric ultrasound? Check out the following posts from the Scan:

Access the Portal Venous System Safely

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Transjugular intrahepatic portosystemic shunt (TIPS) placement is a well-studied procedure for patients with variceal bleeding, refractory ascites, and hepatic hydrothorax on optimal medical therapy. Despite its efficacy, TIPS remains one of the more technically challenging procedures, particularly related to safely gaining access into the portal venous system.

A typical TIPS procedure involves internal jugular venous access, hepatic vein catheterization, venography, and wedged CO2 portography, and the most challenging step—retrograde portal vein access prior to tract dilatation and stent placement. When using CO2 portography as a landmark for portal venous access, usually several needle passes are required and each additional needle pass increases the risk of adverse events, such as hepatic artery injury, hemobilia, and damage to surrounding structures (kidney, colon, and lung parenchyma).

There have been multiple ways to mitigate this issue, such as biplanar angiography, percutaneous transhepatic guidewire placement within the portal venous system, and cone-beam CT guidance. These methods have had various successes but may require increased procedure time, increased radiation dose, or alternative access sites (for example when placing a microwire into the portal venous system via the transhepatic route).

In our opinion, the best solution for accessing the portal venous system during the TIPS procedure is using intravascular ultrasound guidance with a side-firing intracardiac echocardiographic tip (ICE). The benefit of having ICE guidance is intuitive: it allows for direct visualization of the portal venous target, proper selection of the closest hepatic vein to the respective portal vein, and needle guidance using real-time ultrasound visualization. Therefore, ICE guidance reduces the number of needle passes, the risk of hitting critical structures, and the length of the procedure. Previously, ICE guidance has proven its worth in managing complicated TIPS cases, such as portal vein thrombosis, distorted anatomy from prior surgery or neoplastic disease, as well as TIPS for Budd-Chiari syndrome (direct IVC to portal venous access in these cases).

There have been a few retrospective investigations comparing fluoroscopic guidance to ICE guidance for the TIPS procedure. In a study by Kao et al., the authors did a retrospective comparison between ICE and fluoroscopic guidance. It is interesting to note that the ICE operators were only 2 and 3 years out of fellowship versus 20+ years of experience in the conventional group. The data showed that ICE catheter guidance significantly decreased the number of needle passes, contrast volume, fluoroscopy time, procedure time, and radiation exposure. More importantly, ICE largely reduced the number of “outliers” —those occasional cases in which 30+ needle passes and a few hours of fluoroscopy times are required. It is likely in clinical practice that exactly these outlier cases drive up complication rates.

In a different study, by Ramaswamy et al., the authors did a propensity-matched retrospective review. The data showed the procedure time and outcomes were not significantly different between ICE and conventional techniques. However, there was a significant reduction in contrast volume and radiation in the ICE guidance group. The major caveat of the study was that the ICE operators were much earlier in their career than the conventional group, with an average experience of 4.2 years versus 11 years. The difference in operator experience probably indicates that ICE has the potential to decrease the procedure time when adjusted for operator experience.

Based on the available retrospective studies and our experience, a few points can be confirmed.

  1. ICE decreases the number of needle passes, radiation exposure (to both the patient and operator), and contrast volume.
  2. ICE most likely decreases the procedure time, accounting for differences in operator experience.
  3. ICE will largely eliminate outlier cases that are more likely associated with complex anatomy/clinical scenario and have a higher potential to cause major complications.

In our experience, ICE catheter guidance makes the procedure safer in tough situations. Of course, ICE adds costs (~ $1,000/probe). The modality has a pretty steep learning curve, and it requires an additional venipuncture. In addition, the (more inexperienced) conventional operator can achieve excellent results in routine and/or complex scenarios without using ICE.

In our view, ICE guidance is most helpful in dealing with complex TIPS cases in which a large number of needle passes are expected and complications are frequent. Furthermore, it offers a back-up option when a conventional TIPS procedure runs into unexpected challenges. Instead of blindly sticking another 20 times, we should become familiar with using the available tool (ICE catheter guidance) in our procedural arsenal to provide a safer experience for our patients, ultimately improving outcome in the end-stage liver disease population.

This is a patient referred for re-attempt TIPS from an outside hospital, where multiple attempts of accessing the portal venous system have failed and, therefore, TIPS procedure in the outside hospital had to be aborted. Image A shows the access needle (skinny arrow) directed from the hepatic vein towards a right portal branch (fat arrow). Image B shows the access needle and Bentson guidewire (skinny arrow) within the same right portal branch (fat arrow), indicating successful cannulation. Image C confirms the guidewire (white circle) advanced into the main portal vein. Image D shows the TIPS stent connecting the right portal vein (arrow) with the hepatic vein with free flow of contrast. Portal access was successful on the second puncture with ICE guidance for this (challenging) re-attempt TIPS procedure.

All comments are welcomed; Sasan Partovi can be reached at partovs@ccf.org.

References:

Ramaswamy RS, Charalel R, Guevara CJ et al. Propensity-matched comparison of transjugular intrahepatic portosystemic shunt placement techniques: Intracardiac echocardiography (ICE) versus fluoroscopic guidance. Clin Imaging. 2019; 57:40–44.

Kao SD, Morshedi MM, Narsinh KH, Kinney TB et al. Intravascular Ultrasound in the Creation of Transhepatic Portosystemic Shunts Reduces Needle Passes, Radiation Dose, and Procedure Time: A Retrospective Study of a Single-Institution Experience. JVIR. 2016; 27:1148–1153.

Sasan Partovi, MD, is a staff physician in interventional radiology at The Cleveland Clinic Main in Cleveland, Ohio. Dr. Partovi’s research interests are focused on innovative endovascular treatment options for end-stage renal disease and end-stage liver disease patients. Dr. Partovi has been elected as secretary of the American Institute for Ultrasound in Medicine’s (AIUM’s) Interventional-Intraoperative Community of Practice.

Xin Li, MD, is a radiology resident at the Hospital of the University of Pennsylvania in Philadelphia, Pennsylvania. Dr. Li attended Case Western Reserve University School of Medicine in Cleveland, Ohio, and is pursuing a career in interventional radiology. He currently serves on the Resident, Fellow, and Student Governing Council of the Society of Interventional Radiology.

Interested in learning more about POCUS? Check out the following posts from the Scan: