Contrast-enhanced Ultrasound Research Articles

Incremental clinical value of intraplaque neovascularization in predicting recurrent ischemic stroke

AbstractObjectiveCarotid intraplaque neovascularization (IPN) detected by contrast‐enhanced ultrasound (CEUS) is a risk factor for recurrent ischemic stroke. However, it is still unclear whether IPN can be used to accurately identify patients with recurrent ischemic stroke in clinical practice. Herein, we investigated the clinical predictive value of IPN for recurrent ischemic stroke in a real‐world setting.MethodsWe enrolled 200 patients with ischemic stroke and atherosclerotic carotid stenosis who were followed up for 2 years. The endpoint was recurrent ischemic stroke. Cox regression and subgroup analyses were employed to assess whether treatment affected the relationship between IPN and recurrent ischemic stroke. The net classification index (NRI) and integrated discriminant improvement index (IDI) were used to validate the additional clinical value of IPN in identifying recurrent ischemic stroke.ResultsDuring the 2‐year follow‐up, 36 patients experienced recurrent ischemic stroke. Cox regression analyses showed that IPN (grade 2), hypoechoic plaque, high homocysteine levels, and smoking were independent risk factors for recurrent ischemic stroke. Additional IPN evaluation may increase the NRI (0.512; 95% confidence interval [CI]: 0.083–0.624) and IDI (0.151; 95% CI: 0.010–0.213) for identifying high‐risk patients with recurrent ischemic stroke. In addition, in the subgroup undergoing revascularization, the proportion of IPN (grade 2) was significantly higher in patients with recurrent ischemic stroke than in patients with nonrecurrent ischemic stroke (p = 0.001).InterpretationIn clinical settings, IPN, assessed by CEUS, may provide additional clinical value for predicting recurrent ischemic stroke, helping to identify patients with ischemic stroke who require close follow‐up.

Acoustic radiation force impulse (push pulse)-induced lung hemorrhage: investigating the effect of ultrasound contrast agent in rabbits.

Acoustic radiation force impulse (ARFI) elastography and contrast-enhanced ultrasonography (CEUS) are emerging techniques that are becoming common in ultrasound examinations. We previously reported that ARFI (push pulse) induced lung hemorrhage in rabbits, indicating that greater risks are associated with ARFI than with conventional ultrasound. In this study, we assessed the risk of lung hemorrhage under a combination of ARFI elastography and CEUS, considering potential exacerbation of ARFI-induced lung hemorrhage as a result of the ultrasound contrast agent (UCA) used in CEUS. Twenty-three rabbits were divided into non-UCA and UCA groups. ARFI exposure parameters were set at six mechanical index (MI) levels (0.29, 0.45, 0.60, 0.88, 1.0, 1.39) in non-UCA groups and five MI levels (0.29, 0.66, 0.88, 0.97, 1.25) in UCA groups. Lung exposure was performed bilaterally through the intercostal space in each rabbit. Lung damage was assessed through macroscopic and microscopic observation post euthanasia. Lung hemorrhage was detected at MI0.3 levels of 0.88 or higher. Logistic regression analyses showed that MI0.3 was a statistically significant factor for occurrence of lung hemorrhage in both non-UCA and UCA groups, and the MI0.3 threshold (ED05) for inducing lung hemorrhage was 0.68 and 0.71, respectively. However, multivariate logistic regression and linear regression analyses across all samples indicated that UCA did not significantly affect the occurrence or area of lung hemorrhage. This study demonstrates that UCA does not significantly worsen ARFI-induced lung hemorrhage in terms of occurrence or severity. However, risks and benefits of ARFI elastography on the lung should be considered, irrespective of UCA administration.

Enhancing deep-seated hepatocellular carcinoma detection: assessing the added value of high mechanical index setting in sonazoid-based contrast-enhanced ultrasound during post-vascular phase.

This retrospective study aimed to investigate the role of an additional high mechanical index (MI) setting scan during the post-vascular phase (PVP) in detecting deep-seated hepatocellular carcinoma (HCC) lesions. A total of 805 confirmed HCCs, which underwent Sonazoid-based contrast-enhanced ultrasound (CEUS) between January 2014 and October 2021, were included. Low MI scan was initially employed for lesion detection during the PVP, followed by high MI scan. Propensity score matching (PSM) was utilized to address confounding variables. Of the 805 study lesions, 668 were detected as perfusion defects at the initial low MI setting, while 137 remained undetected. Among these 137 undetected lesions, 77 were identified at the subsequent high MI setting, whereas 60 remained undetected. Lesions that were larger (18.69±11.27mm vs. 16.55±7.42mm, p = 0.006), more superficial (6.06±2.41cm vs. 7.40±2.74cm, p < 0.001), and hypoechoic (482/668 vs. 62/137, p < 0.001) were detectable at the initial low MI setting. Male patients benefited more from the additional high MI scan (63/97 vs. 14/40, p < 0.001). Lesions identified with additional high MI were larger (18.30±8.76mm vs. 14.30±4.34mm, p < 0.001) and deeper than undetected ones (8.48±2.48cm vs. 6.02±2.43cm, p < 0.001). After PSM, depth was shown to be an independent predictor in multivariate analysis (odds ratio: 1.557, 95% confidence interval: 1.249-1.941). The depth cutoff was 7.75 cm, with a sensitivity of 0.681, specificity of 0.851, and area under the curve of 0.774. The additional high MI setting scan during the PVP of Sonazoid-based CEUS leads to enhanced detection of deep-seated HCCs.

An artificial intelligence-based recognition model of colorectal liver metastases in intraoperative ultrasonography with improved accuracy through algorithm integration.

Contrast-enhanced intraoperative ultrasonography (CE-IOUS) is crucial for detecting colorectal liver metastases (CLM) during surgery. Although artificial intelligence shows potential in diagnostic systems, its application in CE-IOUS is limited. This study aimed to develop an automatic tumor detection model using Mask region-based convolutional neural network (Mask R-CNN) for CE-IOUS images. CE-IOUS videos of the CLM from 121 patients were collected, generating ground truth data. A total of 2659 images were obtained. Two models were developed: the basic recognition model (BRM), which was trained on CE-mode images, and the subtraction model (SM), which used images created by a subtraction algorithm that highlighted the differences in pixel values between the basic-mode and CE-mode images. The subtraction algorithm focuses on echogenicity differences. These two models were combined into a combination model (CM), which assessed outcomes using the prediction probabilities from both models. The optimal epochs were determined by the maximum area under the curve (AUC), and the thresholds were calculated accordingly. BRM, SM, and CM achieved 89.4%, 86.6%, and 96.5% accuracy, respectively. CM outperformed the individual models, achieving an AUC of 0.99. A novel automated recognition model was developed for accurate CLM detection in CE-IOUS by integrating image- and algorithm-based models.

Detection of early renal perfusion changes by contrast-enhanced ultrasonography in dogs with preclinical myxomatous mitral valve disease.

Since the prognosis of myxomatous mitral valve disease (MMVD) varies, its characterization is clinically relevant, and renal impairment has been identified as one of its associated factors. Intrarenal Doppler ultrasonography (IRD), an intrarenal hemodynamic assessment method, is useful for predicting cardiac- and renal-related death but cannot detect early changes in dogs with preclinical MMVD. Contrast-enhanced ultrasonography (CEUS), another intrarenal hemodynamic assessment method, may identify earlier changes; however, renal perfusion evaluations using CEUS have not yet been performed on dogs with MMVD. We hypothesized that CEUS detects changes earlier than IRD in dogs with preclinical MMVD. This prospective, cross-sectional study examined renal perfusion in dogs without cardiac disease and preclinical MMVD dogs of different American College of Veterinary Internal Medicine stages using CEUS and compared it with IRD indices. Twenty-three dogs with MMVD (ten stage B1 and thirteen stage B2) and 12 control dogs without cardiac disease were included. The rise times of the renal cortex and medulla were measured from a time-intensity curve. The rise time of the cortex was longer in dogs with stage B2 MMVD than in control dogs, while that of the medulla was shortened in the right ventricular dysfunction group in stage B2. No changes were observed in IRD indices (the resistance index and venous impedance index). In conclusion, CEUS detected changes in renal perfusion in dogs with preclinical MMVD even when IRD indices remained unchanged, suggesting the utility of CEUS in evaluations of renal perfusion in MMVD dogs.

Ultrasound-guided percutaneous microwave ablation of primary hyperthyroidism: security and efficacy analysis

Objectives This study aimed to analyze the safety, efficacy, and application prospects of ultrasound-guided microwave ablation (MWA) in the treatment of primary hyperthyroidism. Methods Eight patients with primary hyperthyroidism who underwent ultrasound-guided glandular volume reduction between January 2021 and December 2022 were included in this study. Pre- and postablative examinations, including grayscale ultrasound, contrast-enhanced ultrasound (CEUS), laboratory examination, antithyroid drug (ATD) dosage, and quality of life (QoL) assessment via Thyroid-Specific Patient-Reported Outcome Short-Form (ThyPRO-39), were analyzed retrospectively. The main ultrasound follow-up times were 1, 3, 6, and 12 months after ablation. Thyroid function was reviewed 1 week after ablation, and the subsequent reexamination time was determined according to the patient’s specific test results and ATD adjustment. The final efficacy was comprehensively analyzed according to the patient’s medication status, thyroid function, thyroid volume, and QoL score. Results All 8 patients successfully received MWA for primary hyperthyroidism, and none of them experienced serious complications. By the end of the follow-up, 5 of the 8 patients had stopped taking ATDs, 3 of the 8 patients had reduced ATD dosages, and all of them maintained stable thyroid function. Although descriptive analysis was performed because of the small sample size, patients’ thyroid volume reduction, and obvious improvements in goiter symptoms, hyperthyroid symptoms, anxiety, etc., were observed during our follow-up. Conclusion Ultrasound-guided MWA for reducing thyroid gland volume in primary hyperthyroidism patients is a new, safe, and effective minimally invasive treatment method that is a good choice for patients who cannot or refuse traditional treatment methods.

Polydopamine Nanobowl-Armoured Perfluorocarbon Emulsions: Tracking Thermal- and Photothermal-Induced Phase Change through Neutron Scattering.

Anisotropic polydopamine nanobowls (PDA NBs) show significant promise in biomedicine, distinguished by their unique optical properties and superior cellular uptake compared to spherical nanoparticles. This study presents a novel approach for creating multistimuli-activated PDA NB-armored emulsions, encapsulating perfluorohexane (NB-H) and perfluoropentane (NB-P) cores, with applications in controlled delivery and ultrasound imaging. Thermal and photothermal activation induced distinct responses in the emulsions, as evidenced by optical microscopy and thermogravimetric analysis. For the first time, neutron scattering techniques (SANS and USANS) under contrast matching conditions are applied to investigate these materials, revealing detailed droplet and microbubble structures and phase transition dynamics. These results show that NB-H droplets resist phase change under direct heating, whereas NB-P droplets respond more readily, exhibiting significant bubble formation. During photothermal activation with short near-infrared (NIR) exposure (15 min at 400mW cm-2), SANS and USANS analyses reveal varying degrees of phase transition, proving this activation method to be more effective than direct heating. Importantly, NB-H and NB-P droplets have excellent ultrasound contrast enhancement and biocompatibility, indicating their potential for contrast-enhanced ultrasound imaging, theranostics, and photothermal applications. This comprehensive study advances the understanding of multifunctional colloidal materials in biomedicine, contributing essential knowledge to this rapidly evolving field.

Safety of the contrast enhancement agent sulfur hexafluoride in ultrasound: Analysis of the Federal Drug Administration Adverse Event Reporting System database

ABSTRACT Background and Objectives Sulfur hexafluoride is an inert gas that creates microbubbles to enhance diagnostic accuracy in a variety of ultrasound (US) studies and is widely used in EUS. We analyzed the reported adverse events (AEs) of the US contrast agent, sulfur hexafluoride, extensively used during EUS procedures using a US national database. Methods From December 2008 to January 2024, AEs reported in the Federal Drug Administration Adverse Event Reporting System database for sulfur hexafluoride were examined. Results There were 1069 individual reports analyzed. Reports were excluded if they contained drugs other than sulfur hexafluoride. Echocardiogram (70.9%) was the common diagnostic study in which sulfur hexafluoride was administered. The most common AE reported was anaphylactic reaction (n = 179, 16.7%), followed by hypotension (n = 162, 15.2%), cardiac arrest (n = 161, 15.1%), and dyspnea (n = 159, 14.9%). The most common gastrointestinal AE was nausea (n = 135, 12.6%). Severity of AEs ranged from nonserious to death. Death associated with sulfur hexafluoride use was reported in 58 patients (5.4% of AE reports). Conclusions Anaphylactic reaction was the most common AE reported with sulfur hexafluoride use, and severe AEs including death may be more common than prior large, retrospective, observational studies to date have suggested.

Quantile analysis for financial bubble detection and surveillance

Understanding and monitoring financial bubbles is critical, as they can lead to market instability, asset price crashes, and economic downturns with widespread consequences. This article explores the usefulness of quantile regression (QR) technique in detecting and surveilling financial bubbles, encompassing both global testing and real‐time monitoring. We demonstrate that the QR‐based quantile unit root test, coupled with an optimal quantile selection technique, serves as an effective tool for a global bubble test without necessitating additional recursive techniques. Moreover, we propose two QR‐based bubble monitoring techniques. We show that the monitoring statistics follow a random variate under the null hypothesis of no bubbles but diverge to positive infinity in the presence of a mildly explosive bubble, and hence consistently date the origination of a bubble. Monte Carlo simulations suggest that compared with their LS counterparts, in the presence of skewed distributions, the QR‐based global test delivers substantially greater power, while the QR‐based monitoring procedures offer higher bubble detection rate and more accurate dating of the bubble origination. As an illustration, we conduct a pseudo real‐time monitoring exercise with the S&amp;P 500 composite index.

Contrast-Enhanced Ultrasound for Diagnosing Thyroid Nodules With Indeterminate Cytology: A Retrospective Study.

A small number of thyroid nodules cannot be clearly diagnosed using ultrasound-guided fine needle aspiration biopsy. Contrast-enhanced ultrasound (CEUS) has high diagnostic performance for thyroid nodules. We explored the value of CEUS for diagnosing thyroid nodules with indeterminate cytology. Between September 2019 and July 2022, 27,646 patients with thyroid nodule(s) underwent conventional ultrasound (CUS) in our hospital. From these patients, 597 nodules were subjected to CEUS and ultrasound-guided fine needle aspiration biopsy and 116 thyroid nodules with indeterminate cytology diagnose were enrolled in this study. The independent risk factors for predicting malignancy were determined using univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curves were drawn for CUS, CEUS, and CEUS combined with CUS. The area under the curve (AUC) was calculated and compared. Of the 116 thyroid nodules, 40 (34.5%) were benign and 76 (65.5%) were malignant. Univariate analysis showed that the shape, echogenicity, margin, microcalcification, enhancement intensity, enhancement homogeneity, wash in, and wash out were significantly different between benign and malignant thyroid nodules (all p < 0.05). Multivariate logistic regression analysis showed that taller-than-wide, irregular margin, microcalcification, hypo-enhancement, heterogeneity enhancement, synchronous/slower wash in, and synchronous/slower wash out were independent risk factors for malignancy (all p < 0.05). ROC curve analysis showed that the AUC of CUS and CEUS were 0.769 and 0.848, respectively. No significant difference was observed in the AUC between the two modalities (p > 0.05). However, the AUC (0.934) of the CUS combined with CEUS was significantly higher than that of CEUS or CUS alone (both p < 0.05). CEUS is helpful in diagnosing thyroid nodules with indeterminate cytology. CUS combined with CEUS is highly valuable for predicting malignancy.

Correlation of early contrast-enhanced ultrasound parameters with postoperative graft function and at six months after kidney transplantation

Abstract Purpose We analyzed which contrast-enhanced ultrasound (CEUS) parameters are associated with reduced kidney function in the early postoperative period and are prognostic for kidney function six months after transplantation. Materials and Methods This prospective observational study included 74 patients in whom quantitative CEUS analysis and Doppler ultrasound were performed early after kidney transplantation (10±6 days). For each region of interest (ROI) the time-to-peak intensity (TTP) and the respective delta between ROIs within interlobar artery, cortex, and medulla were compared. Results were correlated with kidney function at the time of imaging and six months later. Results Patients with an eGFR&lt;30 ml/min at the time of investigation had significantly slower cortical enhancement with a longer cortical TTP (cTTP: 16.1±0.9 vs. 11.7±0.7 sec, p&lt;0.001), as well as a significant delay between the arterial and cortical phases (c–a), as shown in longer ∆TTP (c–a): 8.2±0.9 vs. 4.2 ± 0.5 sec, p&lt;0.001. There was a significant negative correlation between cTTP and eGFR with a correlation coefficient of −0.37 (p&lt;0.001), as well as between ∆TTP (c–a) and eGFR with a correlation coefficient of −0.40 (p&lt;0.001). Reduced kidney function after 6 months correlated significantly with the findings of the initial CEUS examination (p=0.005, correlation coefficient −0.39). Conclusion CEUS revealed significant differences in temporal enhancement dynamics in patients with reduced kidney function after transplantation. Quantitative CEUS might therefore be able to depict graft function regarding microvascular damage and be of prognostic value regarding long-term renal outcomes.

Image Features and Diagnostic Value of Contrast-Enhanced Ultrasound for Ductal Carcinoma In Situ of the Breast: Preliminary Findings.

To explore the image features and the diagnostic value of contrast-enhanced ultrasound (CEUS) for ductal carcinoma in situ (DCIS) of the breast. A total of 96 female patients with a solitary and histologically proven DCIS were analyzed retrospectively, and 100 female cases of invasive ductal carcinoma (IDC) lesions were used as the control group. The Breast Imaging Reporting and Data System (BI-RADS) category of breast lesions was assessed according to conventional ultrasound features. The DCIS lesions were classified into mass type and non-mass type. The CEUS characteristics of these breast lesions were retrospectively analyzed qualitatively and quantitatively. The final gold standard was biopsy or surgery with histo-pathological examination. Comparing the ultrasound images of DCIS with that of IDC, there were significant differences in echo pattern, calcification morphology, and calcification distribution (p < .05 for all). There was a significant difference between DCIS and IDC in enhancement intensity, perfusion defects, peripheral high enhancement, intratumoral vessels, and arrival time (AT) (p < .05 for all). In the logistic multivariate regression analysis, two indicators linked with DCIS were recognized: perfusion defects (p = .002) and peripheral high enhancement (p < .001). In forecasting DCIS, the logistic regression equation resulted in an AUC of 0.689, a specificity of 0.720, and a sensitivity of 0.563. CEUS showed differences in enhancement characteristics between DCIS and IDC, with perfusion defects and peripheral high enhancement being associated with DCIS.

Contrast-enhanced ultrasound can differentiate the level of glioma infiltration and correlate it with biological behavior: a study based on local pathology.

The objective of this study is to assess the diagnostic efficacy of contrast-enhanced ultrasound (CEUS) in determining the level of glioma infiltration and to investigate its correlation with pathological markers. A prospective study involving 16 adult glioma patients was conducted. Preoperative US-(Magnetic Resonance)MR fusion imaging was utilized for tumor infiltration localization, while CEUS was employed to assess hemodynamic alterations. Parameters such as peak intensity (PI), rise time (RT), time to peak (TTP), and area under the curve (AUC) were measured. Utilizing contralateral normal brain tissue as the reference standard. The Kruskal-Wallis H-test was conducted to compare CEUS and pathological parameters (significance level, p < 0.05; bonferroni correction) among tumor margins, infiltration zones, and normal tissues, as well as between low-grade glioma (LGG) and high-grade glioma (HGG) within the infiltration zone, based on whole slide pathological images analysis. Spearman correlation analysis was employed to determine the correlation coefficient between hemodynamics and pathology. Receiver operating characteristic (ROC) curves were drawn to evaluate the performance of CEUS in tumor classification. From tumor margin to normal tissue, PI, AUC, Ki67, EGFR, and 1p/19q showed a significant decreasing trend, while TTP, IDH-1, and MGMT gradually increased. RT was lower at the tumor margin but did not show statistically significant differences. In the infiltration zones, there was a significant increase in parameters such as PI, normalized PI (Nor_PI), AUC, and Ki67 from LGG to HGG, while RT, Nor_RT, TTP, Nor_TTP, IDH-1, and MGMT significantly decreased. Nor_AUC and EGFR increased but were not significant, and 1p/19q decreased but was not significant. RT and Nor_TTP were independent risk factors for distinguishing between LGG and HGG in the infiltration zone, with a combined diagnostic efficacy ROC of 0.891. The sensitivity reached 96.64% and the specificity reached 82.35%. There was a significant correlation between hemodynamic indicators and pathological indicators. CEUS can effectively differentiate levels of infiltration zones, which correlates with their biological behavior, with RT + Nor_TTP showing particularly highest diagnostic efficacy. These findings contribute to improving the accuracy of diagnosing infiltration zones and provide essential biological insights for subsequent treatments.

Do as Sonographers Think: Contrast-Enhanced Ultrasound for Thyroid Nodules Diagnosis via Microvascular Infiltrative Awareness.

Dynamic contrast-enhanced ultrasound (CEUS) imaging can reflect the microvascular distribution and blood flow perfusion, thereby holding clinical significance in distinguishing between malignant and benign thyroid nodules. Notably, CEUS offers a meticulous visualization of the microvascular distribution surrounding the nodule, leading to an apparent increase in tumor size compared to gray-scale ultrasound (US). In the dual-image obtained, the lesion size enlarged from gray-scale US to CEUS, as the microvascular appeared to be continuously infiltrating the surrounding tissue. Although the infiltrative dilatation of microvasculature remains ambiguous, sonographers believe it may promote the diagnosis of thyroid nodules. We propose a deep learning model designed to emulate the diagnostic reasoning process employed by sonographers. This model integrates the observation of microvascular infiltration on dynamic CEUS, leveraging the additional insights provided by gray-scale US for enhanced diagnostic support. Specifically, temporal projection attention is implemented on time dimension of dynamic CEUS to represent the microvascular perfusion. Additionally, we employ a group of confidence maps with flexible Sigmoid Alpha Functions to aware and describe the infiltrative dilatation process. Moreover, a self-adaptive integration mechanism is introduced to dynamically integrate the assisted gray-scale US and the confidence maps of CEUS for individual patients, ensuring a trustworthy diagnosis of thyroid nodules. In this retrospective study, we collected a thyroid nodule dataset of 282 CEUS videos. The method achieves a superior diagnostic accuracy and sensitivity of 89.52% and 94.75%, respectively. These results suggest that imitating the diagnostic thinking of sonographers, encompassing dynamic microvascular perfusion and infiltrative expansion, proves beneficial for CEUS-based thyroid nodule diagnosis.

Integrating Contrast-enhanced US to O-RADS US for Classification of Adnexal Lesions with Solid Components: Time-intensity Curve Analysis versus Visual Assessment.

Purpose To compare the diagnostic performance of time-intensity curve (TIC) analysis and subjective visual assessment of contrast-enhanced US (CEUS) when integrated with the Ovarian-Adnexal Reporting and Data System (O-RADS) US risk stratification system for characterizing adnexal lesions with solid components. Materials and Methods In this prospective multicenter study conducted from September 2021 to December 2022, female individuals with suspected adnexal lesions containing solid components detected at routine US were enrolled. All participants underwent preoperative CEUS examinations. Histopathologic findings were used as the reference standard for diagnosis. Lesions were classified according to the O-RADS US system. Enhancement of solid tissue compared with the outer myometrium was evaluated using both TIC analysis and subjective visual assessment. The diagnostic performance of O-RADS alone and each CEUS assessment method when integrated with the O-RADS US system was assessed and compared using receiver operating characteristic curve analysis. Results A total of 180 lesions (80 malignant and 100 benign histopathologic outcomes) in 175 participants (median age, 47 years [IQR, 33-56]) were analyzed. Incorporating CEUS (assessed through both TIC analysis and subjective visual assessment) with O-RADS US showed significantly improved diagnostic performance over O-RADS US alone, with an area under the receiver operating characteristic curve (AUC) of 0.86 (95% CI: 0.80, 0.91) compared with 0.78 (95% CI: 0.71, 0.84). No evidence of a difference was observed between the AUCs of TIC analysis and subjective visual assessment in the enhancement evaluation of solid tissue with CEUS for adnexal malignancy categorization (P = .83). Conclusion Subjective visual assessment and TIC analysis of CEUS features when integrated with the O-RADS US scoring system showed comparable diagnostic performance in assigning adnexal malignancy risk. Keywords: Adnexal Lesions, Contrast-enhanced US, O-RADS, Time-intensity Curve Analysis Supplemental material is available for this article. © RSNA, 2024.

Suppression of the Tissue Component With the Total Least‐Squares Algorithm to Improve Second Harmonic Imaging of Ultrasound Contrast Agents

ABSTRACTThe second harmonic (SH) of ultrasound contrast agents (UCAs) is widely used in contrast‐enhanced ultrasound imaging; however, is affected by the nonlinearity of surrounding tissue. Suppression of the tissue component based on the total least‐squares (STLS) algorithm is proposed to enhance the SH imaging of UCAs. The image blocks of pulse‐inversion‐based SH images before and after UCA injections are set as the reference and input of the total least‐squares model, respectively. The optimal coefficients of the model are obtained by minimizing the Frobenius norm of perturbations in the input and output signals. After processing all image blocks, the complete SH image of UCAs is obtained by subtracting the optimal output of the model (i.e., the estimated tissue SH image) from the SH image after UCA injection. Simulation and in vivo experiments confirm that the STLS approach offers clearer capillaries. For in vivo experiments, the STLS‐based contrast‐to‐tissue ratios and contrasts increase by 26.90% and 56.27%, as well as 26.99% and 56.43%, respectively, compared with those based on bubble‐echo deconvolution and pulse inversion bubble‐wavelet imaging methods. The STLS approach enhances the SH imaging of UCAs by effectively suppressing more tissue SH components, having the potential to provide more accurate diagnostic information for clinical applications.

Diagnostic value of transvaginal contrast-enhanced ultrasound in identifying benign and malignant endometrial lesions and assessing myometrial invasion.

The objective of this study was to evaluate the diagnostic value of transvaginal contrastenhanced ultrasound (CEUS) in differentiating benign from malignant endometrial lesions and assessing the extent of myometrial invasion. A total of 70 patients who underwent surgery for endometrial lesions at the authors' hospital were selected. Transvaginal ultrasound examination and CEUS were performed for quantitative and qualitative analysis. Based on the CEUS results, an International Federation of Gynecology and Obstetrics (FIGO) disease grade was assigned and compared with pathological findings. Postmenopausal vaginal bleeding is a key clinical manifestation of endometrial carcinoma. Among the patients with endometrial carcinoma, compared with normal myometrium, the lesion areas exhibited a greater rate of rise (defined as enhanced intensity divided by enhancement time) and a shorter half-clearance time (P<0.05). These findings suggest that in endometrial carcinoma, the contrast agent displays a "fast-in/fast-out/hyperenhancement" perfusion pattern. In contrast, the characteristic perfusion pattern for benign endometrial lesions is low enhancement (P<0.05). The diagnostic accuracy of CEUS in detecting myometrial invasion was 88% (22 of 25 cases). Transvaginal CEUS is a practical and effective diagnostic imaging method for distinguishing between benign and malignant endometrial lesions. It can also be used to evaluate the depth of myometrial invasion in patients with early-stage endometrial carcinoma.

Transient Perivascular Inflammation of the Carotid Artery Syndrome: A Case Report with Diagnostic Insights from Vessel Wall Imaging and Contrast-enhanced Ultrasonography

Transient perivascular inflammation of the carotid artery (TIPIC) syndrome is a rare disease accompanied by acute neck pain and specific pathologic changes in the carotid artery and surrounding tissue. Here, we present a case diagnosed with typical imaging features, including extensive enhancement with luminal narrowing on vessel wall imaging and the presence of microbubbles on contrast-enhanced ultrasonography. These findings provide valuable insights into the pathophysiology of TIPIC syndrome and importance of imaging modalities for early detection and management.

The Relationship Between Rim-like Enhancement on Pre-ablation Contrast-enhanced Ultrasound of Colorectal Liver Metastasis and Early Intrahepatic Progression After Thermal Ablation: A Preliminary Study

ObjectiveTo investigate the relationship between the rim-like enhancement pattern on pre-ablation contrast-enhanced ultrasound (CEUS) of colorectal liver metastasis (CRLM) and the therapeutic efficacy of percutaneous microwave ablation (MWA). MethodsPatients with CRLM underwent MWA and were evaluated using CEUS before ablation in our hospital between February 2020 and February 2023 were enrolled in this retrospective study. The enhancement patterns of CRLM were assessed by two radiologists and classified as rim-like enhancement and non-rim-like enhancement patterns. The therapeutic outcomes, including cumulative intrahepatic progression rate and early intrahepatic progression rate, were followed up and analyzed. ResultsOverall, 50 patients with 121 nodules were enrolled. Rim-like enhancement pattern was observed in 18 patients (18/50, 36.0%). The cumulative intrahepatic progression rate was significantly higher in the rim-like enhancement group than the rate in the non-rim-like enhancement group (p = 0.022). The early intrahepatic progression rate in the rim-like enhancement group was also significantly higher than the rate in the non-rim-like enhancement group (12/17, 70.6% vs. 6/24, 25.0%, p = 0.005). The multivariable analysis demonstrated that the rim-like enhancement pattern of CRLM was a significant risk factor associated with early intrahepatic progression after MWA (p = 0.013). ConclusionRim-like enhancement pattern on pre-ablation CEUS of CRLM was associated with a higher risk of intrahepatic progression after MWA.

Utilizing the Postvascular Phase of Contrast-Enhanced Ultrasound to Predict Breast Cancer Lymph Node Metastasis

Background and Objectives: To evaluate the value of the postvascular phase of contrast-enhanced ultrasound (CEUS) in differentiating between benign and metastatic lymph nodes (LNs) in patients with breast cancer (BC). Materials and Methods: This study retrospectively analyzed 96 suspicious LNs in the lymphatic drainage area of the breast from 90 patients with BC. All LNs were assessed by conventional ultrasound (US) and CEUS following intravenous Sonazoid injection. All LNs underwent puncture biopsy, and pathological results were obtained. The correlations between US and CEUS indicators of LNs and LN metastasis (LNM) were analyzed. Results: Of the 96 LNs, 66 were metastatic. Overall, 80.00% (24/30) of the benign LNs exhibited relative hyper-enhancement in the postvascular phase, whereas 96.97% (64/66) of the metastatic LNs exhibited relative hypo-enhancement (p &lt; 0.001). This CEUS finding was highly predictive of metastasis, with a sensitivity of 96.97%, specificity of 80.00%, positive predictive value of 91.43%, negative predictive value of 92.31%, and accuracy of 91.67%. The mean postvascular phase intensity (MPI) was significantly lower for malignant (median MPI, 12 dB) than for benign (median MPI, 75 dB) LNs. The postvascular phase was more sensitive, specific, and accurate than conventional US or the vascular phase of CEUS for the diagnosis of LNM, with an area under the curve of 0.95 (95% confidence interval: 0.89–0.99). Conclusions: Qualitative and quantitative indicators of the postvascular phase of CEUS provide a reliable diagnostic approach to differentiate benign and metastatic LNs in patients with BC.