Ultrasound of the bowel with a focus on IBD: the new best practice.

Inflammatory Bowel Disease (IBD) is a lifelong chronic disease affecting any part of the gastrointestinal tract with a predilection for the terminal ileum. IBD patients require repeat imaging throughout the course of their disease, necessitating a safe, noninvasive, available, and repeatable method. Imaging is required at diagnosis, routine surveillance, and acute exacerbation of disease. Ultrasound imaging meets these demands with a high degree of accuracy and wide patient acceptance. Ultrasound provides high-resolution imaging and is excellent for detailed evaluation of the bowel wall and surrounding soft tissues. Regular greyscale bowel evaluation and color Doppler imaging now have accepted standards for evaluating disease activity based on wall thickness, perienteric inflammatory fat, and blood flow, which is invaluable in staging and grading disease. High-resolution dynamic real-time imaging on ultrasound has the ability to show functional as well as morphologic detail, including dysfunctional peristalsis associated with bowel stricture and incomplete mechanical bowel obstruction. Fibrostenotic and penetrating complications of IBD may be associated with an acute or chronic presentation that is easily assessed using ultrasound. Newer software technologies for ultrasound, including Contrast-Enhanced ultrasound and Shear wave elastography, have transformed ultrasound from a basic preliminary imaging technique into a highly sophisticated modality that is now competitive with CT and MR enterography for managing IBD patients. Our long experience with ultrasound of the bowel suggests that the new best practice would include ultrasound as the first test for evaluation of the bowel at any stage of the disease.

Unique portal venous phase imaging discordance between CEUS and MRI: a valuable predictor of intrahepatic cholangiocarcinoma?

PURPOSE: We have long noted unique portal venous phase (PVP) imaging discordance of focal liver masses between CEUS, showing rapid marked washout, and MRI, showing progressive or sustained enhancement. We postulate association of this unique discordance with intrahepatic cholangiocarcinoma (ICC) and causal relationship to different contrast agent behavior. We investigate this unique discordance, propose its clinical significance for ICC diagnosis, and confirm further histologic associations. METHODS: Cases were collected within our CEUS department and from pathology records over a ten-year interval. This retrospective review includes 99 patients, 73 with confirmed ICC and 26 other diagnoses, showing unique PVP discordance. The CEUS and MRI enhancement characteristics were compared for all patients. RESULTS: Unique discordance is identified in 67/73 (92%) ICC and difference between the PVP appearance on MRI and CEUS is statistically significant (p <  0.0001). Arterial phase enhancement did not show statistically significant difference between CEUS and MRI, p >  0.05. Other diagnoses showing unique discordance include especially lymphoma (n = 7), sclerosed hemangioma (n = 6), HCC (n = 4), metastases (n = 2), and other rare entities. CONCLUSION: ICC shows this discrepant intermodality enhancement pattern in a statistically significant number of cases and should be considered along with other LR-M features in at-risk patients. Discordance is also rarely seen in a number of other liver lesions.

A Novel Technology for Resolution of CEUS Imaging Problems in Patients With High BMI and Fatty Liver.

OBJECTIVES: In high-BMI patients with and without fatty liver, we evaluate performance of a commercially available specially designed ultrasound probe (SDP) for scanning at depth. Greyscale and contrast-enhanced ultrasound (CEUS) capability of SDP for parenchymal assessment and liver mass characterization, emphasizing HCC, is compared with standard curvilinear probes. METHODS: This retrospective study included 60 patients. Fifty-five with measured BMI included 46/55 (84%) overweight or obese, and 9/55(16%) in the normal range with severe fatty liver. Fifty-six patients with focal liver abnormality included 37 with a mass and 19 with post-ablative treatment site. Masses included 23 confirmed malignancies, 15 HCC, 4 ICC, and 4 metastases. SDP followed suboptimal ultrasound using a standard probe. Images with varying fat content were compared for depth of penetration on greyscale and ability of CEUS to diagnose tumors. RESULTS: SDP showed statistically significant improvement P = <.05 in CEUS penetration for all degrees of fatty liver (mild, moderate, and severe). In malignant tumors, SDP improved detection of lesion washout in the portal venous/late phase (PVP/LP) at depth >10 cm, and in all malignant masses (P < .05). Fifteen confirmed deep HCC showed arterial phase hyperenhancement on standard probe in 10/15 (67%) and 15/15 (100%) on SDP. PVP/LP washout on standard probe was shown in 4/15 (26%) and on SDP, 14/15, (93%). Therefore, 93% of LR-5 tumors were diagnosed with SDP. Removing necessity for biopsy. CONCLUSIONS: Metabolic syndrome and obesity challenge ultrasound, especially CEUS. SDP overcame limitations of standard probes for CEUS penetration especially in fatty liver. SDP was optimal for the liver mass characterization by detecting washout.

Increasing CEUS utilization in the USA: a call to action for the adult and pediatric body imaging community.

Despite its well-established benefits and a powerful body of scientific literature supporting the efficacy of contrast-enhanced ultrasound (CEUS), it has faced challenges in being fully adopted as a diagnostic and problem-solving tool within the USA. This effort, written by experts in performance of and interpretation of CEUS, acts as a roadmap, for those interested in expanding CEUS within their facility. CEUS benefits from a Champion who is knowledgeable and passionate about its performance and who is capable of transferring evidence-based enthusiasm to others. They must be willing to do the legwork required for the successful implementation of a CEUS program, including increasing referrals, expanding applications, and encouraging the inclusion of CEUS into current and established guidelines. The ability of CEUS to resolve a wide range of indeterminate results which come from CT and MR scan represents one of the most compelling arguments for the use of CEUS, decreasing down-stream testing, and reducing time to diagnosis. As utilization grows, the benefits of CEUS will become apparent to other healthcare teams. However, the ultimate beneficiary of improved CEUS utilization will be the patients themselves, who will have greater access to a safe, speedy, cost effective, reliable, and radiation-free diagnostic imaging tool.

Hepatocellular Carcinoma in Evolution: Correlation with CEUS LI-RADS.

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver with a high incidence worldwide and a high associated mortality. Well-recognized risk factors that cause a predisposition to the development of HCC include chronic infection with the hepatitis B or C virus, alcohol-related and non-alcohol-related fatty liver disease, and cirrhosis. In these chronically diseased livers, benign regenerative nodules can increase in size and develop cellular atypia that progress into dysplastic nodules and ultimately HCC. This sequence of hepatocarcinogenesis is coupled with changes in nodule vascularity, including progressive decreased density of portal triads and induced neoangiogenesis, resulting in increased hepatic arterial recruitment. Changes in vascularity result in an array of patterns of nodule enhancement and washout, which can be sensitively depicted with dynamic real-time contrast-enhanced US. Regenerative nodules are isoenhancing relative to the liver with all phases, while HCC classically shows avid arterial phase hyperenhancement with late mild washout. In between, there is great variation as nodules evolve through progressive grades of dysplasia toward HCC. Observed patterns of enhancement and washout can be used to diagnose or stratify the risk of malignancy in liver nodules by using the diagnostic algorithm described by the American College of Radiology Liver Imaging Reporting and Data System (LI-RADS). This facilitates the detection and close monitoring of potential early-stage disease. LI-RADS categorizes nodules according to a probabilistic likelihood for HCC with criteria for LR-5 nodules that are highly specific for the diagnosis of HCC, allowing treatment without exposing the patient to invasive biopsy. An invited commentary by Fetzer is available online. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article. ©RSNA, 2022.

Contrast-enhanced US in Local Ablative Therapy and Secondary Surveillance for Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) has a high incidence of recurrence following therapy. Therefore, secondary surveillance (scheduled follow-up imaging after treatment) is an important part of disease management. The recent approval in the United States for use of a microbubble-based contrast agent for US liver imaging promotes the increased use of contrast-enhanced US (CEUS) in patients with HCC. Although the criteria for the diagnosis of HCC at CEUS are well described, there is a paucity of published literature describing the role of CEUS in ablative therapy and secondary surveillance. In the setting of ablative therapy, CEUS can have vital roles, including patient selection, intraprocedural guidance, and immediate postprocedural assessment. Although CEUS is not widely used, the authors found that it can be used to accurately detect residual or recurrent tumor, characterize the geographic pattern of recurrence (intrazonal, extrazonal, segmental, or remote), and assess for tumor in vein. In addition, similar to primary surveillance, secondary surveillance includes assessment of the entire liver for evaluation of new nodules. Arterial phase hyperenhancement is the reference standard characteristic of disease recurrence at secondary surveillance with CEUS. ©RSNA, 2019 See discussion on this article by Rodgers.

Bowel Ultrasound State of the Art: Grayscale and Doppler Ultrasound, Contrast Enhancement, and Elastography in Crohn Disease.

Bowel ultrasound (US) is accurate for assessing bowel inflammation and complications in Crohn disease. Additionally, contrast-enhanced US provides a quantitative, objective measurement of inflammatory activity in inflammatory bowel disease, and shear wave elastography predicts the stiffness of bowel, an increase of which suggests less response to medical therapy, often necessitating surgery. Overall, bowel US is an excellent, safe, and repeatable choice for routine surveillance and for urgent imaging. We describe an approach to evaluating inflammatory bowel disease and review its features on standard grayscale US with Doppler imaging and show how contrast-enhanced US and shear wave elastography can distinguish between inflammatory and fibrostenotic bowel.

Role of contrast-enhanced ultrasound in evaluation of the bowel.

Contrast-enhanced ultrasound (CEUS) of the gastrointestinal tract provides vascular information helpful for characterizing masses and other pathologies in and around the bowel, similar to contrast applications in other solid organs. However, the use of microbubble contrast agents for the bowel provides additional unique contributions as it gives both subjective and objective information about mural and mesenteric blood flow, invaluable for the determination of disease activity in those many patients affected by inflammatory bowel disease (IBD). IBD is a lifelong chronic disease and has its peak age of onset in adolescence or young adult life. Today, we have moved away from treating patient's symptoms and strive instead to alter the course of disease by obtaining mucosal healing. Expensive and aggressive biologic therapies and lack of agreement of patient's symptoms with their disease activity and complications necessitate frequent imaging surveillance, which must be safe, readily available, inexpensive, and effective. Ultrasound with the benefit of contrast enhancement meets these requirements and is shown in meta-analysis to be equivalent to CT and MRI scans for these indications.

Hydroxyapatite whisker-reinforced polyetherketoneketone bone ingrowth scaffolds.

Hydroxyapatite (HA) whisker-reinforced polyetherketoneketone (PEKK) bone ingrowth scaffolds were prepared and characterized. High levels of porosity (75-90%) and HA whisker reinforcement (0-40 vol.%) were attained using a powder processing approach to mix the HA whiskers, PEKK powder and a NaCl porogen, followed by compression molding at 350-375 degrees Celsius and particle leaching to remove the porogen. The scaffold architecture and microstructure exhibited characteristics known to be favorable for osteointegration. Scaffold porosity was interconnected with a mean pore size in the range 200-300 microm as measured by micro-computed tomography. HA whiskers were embedded within and exposed on the surface of scaffold struts, producing a microscale surface topography, shown by von Kossa staining and scanning electron microscopy. Therefore, HA whisker-reinforced PEKK bone ingrowth scaffolds may be advantageous for orthopedic implant fixation, including interbody spinal fusion.