Superb microvascular imaging (SMI) compared with conventional ultrasound for evaluating thyroid nodules

The Clinical Application of Superb Microvascular Imaging in Evaluating Thyroid Related Diseases: A Systematic Review

This article reviews all published articles on the application of superb microvascular imaging (SMI) technique in thyroid related diseases before December 31, 2023. SMI, a recently developed ultrasound imaging modality, could display microvascular information by eliminating clutter and preserving low flow signals. Most studies used SMI to help diagnose malignant thyroid nodules and concluded that SMI performed better than color Doppler imaging and power Doppler imaging. At present, there is no consensus when depicting the morphology of vascularity of thyroid nodules (TNs). This problem may be solved by quantitative SMI which makes it possible to quantitatively evaluate the vascularity of TNs. SMI is also applied to evaluate cervical lymph node or thyroid inflammatory diseases. Although, SMI has some limitations, such as no standard for the normal perfusion patterns, and it has a broad application prospect in the diagnosis and management of thyroid related diseases.

Significance of maximum intensity projection technique of multimodal ultrasound imaging in differentiating follicular thyroid carcinoma from benign lesions

Objective

Preoperative diagnosis for follicular thyroid cancer (FTC) remains challenging. The purpose of this study was to explore the maximum intensity projection (MIP) features, which can be utilized for reconstructing and characterizing the structure of microvascular in tissue, associated with FTC, and to explore the independent risk factors for FTC in combination with multimodal ultrasonography and blood indicators.

Methods

This single-center, prospective, single-blind, observational study included patients with suspected follicular thyroid carcinoma based on preoperative ultrasonography findings. All patients underwent routine ultrasonography, contrast-enhanced ultrasonography (CEUS), and correlated blood indexes tests. Offline MIP reconstruction of the CEUS images was performed. The tumor was histologically diagnosed postoperatively. Multivariable logistics regression was utilized for analyzing MIP characteristics combined with multimodal ultrasonography and preoperative blood indicators to identify independent risk factors for FTC.

Results

In this study, 61 thyroid nodules were finally included according to the atretic criteria. (1) Compared with traditional color profile ultrasonography and CEUS, MIP technology can provide more information regarding microvascular characteristics inside thyroid tumors. The short, rod-like, crossed, curved and firework-like features of MIP images revealed statistically significant differences between the benign and malignant groups. (2) Multivariable logistic regression analysis indicated that the firework-like MIP characteristics of microvascular, thyroglobulin (Tg) level and vessel intensity (VI) value were independent risk factors for malignancy.

Conclusion

(1) MIP technology has potential applications in the differential diagnosis of follicular thyroid carcinoma from benign lesions. (2) Firework MIP microvascular characteristics, Tg values and VI values can serve as parameters for the differential diagnosis of follicular thyroid carcinoma from benign lesions. This study provides a novel approach idea for preoperative multimodal differentiation of follicular thyroid carcinoma from benign lesions.

Endoscopic ultrasonography for microvascular imaging without contrast enhancement in the differential diagnosis of pancreatic lesions

OBJECTIVES

Detective flow imaging endoscopic ultrasonography (DFI-EUS) is a recent imaging modality developed for detecting fine vessels without the need for ultrasound contrast agents. The aim of the present study was to evaluate the utility of DFI-EUS for solid pancreatic lesions and to compare the diagnostic ability for pancreatic cancer (PC) between DFI-EUS, directional power Doppler (eFLOW) EUS, and contrast-enhanced harmonic (CH)-EUS.

METHODS

Patients with a pancreatic lesion who underwent DFI-EUS, eFLOW-EUS, and CH-EUS between March 2019 and November 2023 were retrospectively enrolled. Final diagnoses were confirmed by pathologic examination of EUS-guided tissue acquisition and/or resected specimens. Lesions were categorized into the three patterns of poor, mild, and rich vascularity on DFI-EUS and eFLOW-EUS, and hypo-, iso-, and hypervascular on CH-EUS. PC was defined as a poor pattern on DFI-EUS and eFLOW-EUS, and a hypovascular pattern on CH-EUS.

RESULTS

The final diagnoses of 90 examined tumors were PC (n = 57), inflammatory mass (n = 6), autoimmune pancreatitis (n = 13), neuroendocrine tumor (n = 9), and others (n = 5). The sensitivity, specificity, and accuracy for diagnosis of PC were 93%, 82%, and 88%, respectively, on DFI-EUS, 97%, 42%, and 77% on eFLOW-EUS, and 95%, 89%, and 92% on CH-EUS. The accuracy of DFI-EUS was significantly superior to eFLOW-EUS (P = 0.005), but no significant difference was found between DFI-EUS and CH-EUS.

CONCLUSION

DFI-EUS is more sensitive for depicting vasculature than eFLOW-EUS, and has higher diagnostic sensitivity for PC. Evaluation of vascularity on DFI-EUS is useful for the differential diagnosis of pancreatic lesions without the need for intravenous contrast agent.

Combing superb microvascular imaging with shear wave elastography for risk stratification of Thyroid Imaging Reporting and Data System (TI-RADS) 4 thyroid nodules

Background

It is difficult to accurately assess the risk of Thyroid Imaging Reporting and Data System (TI-RADS) 4 thyroid nodules due to the overlap of benign and malignant conventional ultrasound (US) features of nodules. To reduce unnecessary needle biopsies and assist clinical decision-making, this study established a dynamic nomogram incorporating superb microvascular imaging (SMI) and shear wave elastography (SWE) for the risk evaluation of TI-RADS 4 thyroid nodules.

Methods

A total of 248 patients who underwent US, SMI, and SWE with cytological or histopathological results were included in this retrospective study, and were randomly divided into training (174 patients) and verification (74 patients) cohorts. The clinical characteristics and US, SMI, and SWE features of patients were analyzed in the training cohort. The least absolute shrinkage and selection operator (LASSO) regression and multivariate logistic regression were used to screen parameters and construct dynamic nomogram. The receiver operating characteristic (ROC) curves, calibration curve, and decision curve were used to evaluate the performance of the nomogram.

Results

A dynamic nomogram was constructed based on age [odds ratio (OR) =0.954; P=0.005] , shape (OR =0.345; P=0.041), SMI (OR =9.511; P<0.001), and SWE (OR =3.670; P=0.001). The nomogram showed excellent discrimination both in the training [area under the curve (AUC): 0.848; 95% confidence interval (CI): 0.784-0.911] and validation (AUC: 0.862; 95% CI: 0.780-0.944) cohorts, and better than US, SMI, and SWE alone in all cohorts (P<0.05). The Nomo-score of each patient was calculated and the cut-off value was 0.607 which can be used to distinguish high-risk and low-risk patients.

Conclusions

The SMI and SWE show added predictive value on risk stratification in patients with TI-RADS 4 thyroid nodules and a dynamic nomogram was constructed to screen high-risk individuals and assist the clinical decision-making.

Transabdominal ultrasound evaluation of vascularity of gallbladder lesions: particularly those with wall thickening

Gallbladder wall thickening is relatively common in clinical settings, and for appropriate diagnosis, the size, shape, internal structure, surface contour, and vascularity of the gallbladder wall must be evaluated. Morphological evaluation is the most important; however, some gallbladder lesions resemble gallbladder cancer in imaging studies, making differential diagnosis challenging. Vascular evaluation is indispensable for a precise diagnosis in these cases. In this review, we present the current status of vascular evaluation using US and diagnosis using vascular imaging for gallbladder lesions, including those presenting with wall thickening. To date, several ultrasound imaging techniques have been developed to assess vascularity, including Doppler imaging with high sensitivity, use of contrast agents, and microvascular imaging using a novel filter for Doppler imaging. Although conventional color Doppler imaging is rarely used for the diagnosis of gallbladder lesions, the efficacy of contrast-enhanced ultrasound in assessing the vascularity, enhancement pattern, or timing of enhancement/washout has been reported. Presence of multiple irregular microvessels has been speculated to indicate malignancy. However, few reports on microvessels have been published, and further studies are required for the precise diagnosis of gallbladder lesions with microvascular evaluation.

Clinical application of intraoperative ultrasound superb microvascular imaging in brain tumors resections: contributing to the achievement of total tumoral resection

BACKGROUND

To investigate whether the intraoperative superb microvascular imaging(SMI) technique helps evaluate lesion boundaries compared with conventional grayscale ultrasound in brain tumor surgery and to explore factors that may be associated with complete radiographic resection.

METHODS

This study enrolled 57 consecutive brain tumor patients undergoing surgery. During the operation, B-mode and SMI ultrasound evaluated the boundaries of brain tumors. MRI before and within 48h after surgery was used as the gold standard to evaluate gross-total resection(GTR). The ultrasound findings and GTR results were analyzed to determine the imaging factors related to GTR.

RESULTS

A total of 57 patients were enrolled in the study, including 32 males and 25 females, with an average age of 53.4 ± 14.1 years old(range 19 ~ 80). According to the assessment criteria of MRI, before and within 48 h after the operation, 37(63.9%) cases were classified as GTR, and 20(35.1%) cases were classified as GTR. In comparing tumor interface definition between B-mode and SMI mode, SMI improved HGG boundary recognition in 5 cases(P = 0.033). The results showed that the tumor size ≥ 5 cm and unclear ultrasonic boundary were independent risk factors for nGTR (OR>1, P<0.05).

CONCLUSIONS

As an innovative intraoperative doppler technique in neurosurgery, SMI can effectively demarcate the tumor's boundary and help achieve GTR as much as possible.

Comparison of Micro-flow Imaging and Contrast-Enhanced Ultrasound in Ultrasound-Guided Microwave Ablation of Benign Thyroid Nodules

OBJECTIVE

The study described here was aimed at ascertaining the utility of micro-flow imaging (MFI) during ultrasound (US)-guided microwave ablation (MWA) of thyroid nodules by contrasting its effectiveness with that of contrast-enhanced ultrasound (CEUS).

METHODS

Seventy-three patients with eighty-eight thyroid nodules who underwent US-guided MWA were included in our study from January 2020 to June 2023. Thirty-five patients underwent CEUS during the MWA process, and thirty-eight patients underwent MFI during the MWA process. We compared the two groups' baseline characteristics, tumor volume (V), volume reduction rate (VRR), complications and clinical characteristics.

RESULTS

Both groups exhibited similar outcomes with respect to V and VRR at 1, 3, 6, 12 and 18 mo after MWA (p > 0.05). Consistency was observed with respect to post-operative complications, supplementary ablation times and surgical duration (p > 0.05). It is worth noting that the MFI group had lower treatment costs compared with the CEUS group (11,337.64 ± 80.93 yuan for the MFI group versus 12,971.23 ± 254.89 yuan for the CEUS group, p < 0.05).

CONCLUSION

In the MWA procedure for thyroid nodules, MFI is similar to CEUS with respect to safety and efficacy. Simultaneously, it offers the advantage of reducing surgical expenses, which lessens the economic burden for patients.

Differential Diagnosis of Solid Pancreatic Lesions Using Detective Flow Imaging Endoscopic Ultrasonography

The differential diagnosis of solid pancreatic lesions (SPLs) using B-mode endoscopic ultrasonography (EUS) is challenging. Detective flow imaging (DFI) offers the potential for detecting low-flow vessels in the pancreas, thus enhancing diagnostic accuracy. This retrospective study aimed to investigate DFI-EUS findings of SPLs and analyze their differential diagnostic accuracy for pancreatic cancer. We included 104 patients with pathologically confirmed SPLs who underwent EUS between April 2021 and June 2023. Expert endosonographers, blinded to the patients' clinical data, evaluated images obtained through B-mode, eFLOW, and DFI-EUS. The frame rate and vessel detection sensitivity were compared between eFLOW and DFI, and the diagnostic criteria for pancreatic cancer were established. The visualization rate for vessels in SPLs was significantly higher with DFI-EUS (96%) compared to eFLOW (27%). Additionally, DFI showed a superior frame rate, sensitivity (99%), and accuracy (88%) for detecting pancreatic cancer, although with a modest specificity (43%). On DFI-EUS, characteristics such as hypovascularity, peritumoral vessel distribution, or spotty vessel form were suggestive of pancreatic cancer. DFI-EUS significantly improved the visualization of vascular structures within the SPLs, highlighting its efficacy as a diagnostic modality for pancreatic cancer.

Thyroid ultrasound and its ancillary techniques

Ultrasound (US) of the thyroid has been used as a diagnostic tool since the late 1960s. US is the most important imaging tool for diagnosing thyroid disease. In the majority of cases a correct diagnosis can already be made in synopsis of the sonographic together with clinical findings and basal thyroid hormone parameters. However, the characterization of thyroid nodules by US remains challenging. The introduction of Thyroid Imaging Reporting and Data Systems (TIRADSs) has improved diagnostic accuracy of thyroid cancer significantly. Newer techniques such as elastography, superb microvascular imaging (SMI), contrast enhanced ultrasound (CEUS) and multiparametric ultrasound (MPUS) expand diagnostic options and tools further. In addition, the use of artificial intelligence (AI) is a promising tool to improve and simplify diagnostics of thyroid nodules and there is evidence that AI can exceed the performance of humans. Combining different US techniques with the introduction of new software, the use of AI, FNB as well as molecular markers might pave the way for a completely new area of diagnostic accuracy in thyroid disease. Finally, interventional ultrasound using US-guided thermal ablation (TA) procedures are increasingly proposed as therapy options for benign as well as malignant thyroid diseases.

Usefulness of Ultrasonographic Detective Flow Imaging for Detecting Parathyroid Tumors: A Report of Two Cases

Parathyroid tumors (PTs) are sometimes difficult to diagnose because they are small and have low-velocity blood flow, which can be missed by current imaging modalities. PTs consist of parathyroid adenoma (PA), parathyroid cyst, and parathyroid carcinoma (PC). Detective flow imaging (DFI) is a new imaging technology that displays low-velocity blood flow. Herein, we report two cases in which DFI was useful for diagnosis of PTs. One patient had a PA and a parathyroid cyst in close proximity, and the other had a PC. To our knowledge, this is the first report to demonstrate the usefulness of DFI in the diagnosis of PTs.

Cerebral Microvascular Imaging in Infants: Scan Technique and Potential Clinical Applications

ABSTRACT

Brain ultrasound in infants, although widely utilized, provides limited functional insights into the brain. Although color and power Doppler ultrasounds have allowed quantitative assessment of cerebral macrovascular flow dynamics, there is no standardized tool integrated into the current neurosonography protocol that allows cerebral microvascular flow assessment. The evaluation of anatomic and functional changes in cerebral microvessels is important, as microvascular alterations have been shown to precede macrovascular and tissue injury in a variety of neurologic diseases of infancy. In this regard, the cerebral microvascular imaging technique is a commercially available, advanced Doppler technique in which slow flow of cerebral microvessels can be detected via a static noise suppression algorithm. This article therefore shares the basic scan technique and clinical examples of the integrated use of microvascular imaging in neurosonography for infants, setting the stage for future clinical integration of the technique.

Serum leucine-rich alpha-2 glycoprotein levels for predicting active ultrasonographic findings in intestinal lesions of patients with Crohn's disease in clinical remission

This study aimed to investigate the cutoff value of leucine-rich alpha-2 glycoprotein (LRG) in predicting active intestinal ultrasonography (IUS) findings in patients with Crohn's disease (CD) in clinical remission. Data were retrospectively collected from patients with CD evaluated using LRG and undergoing IUS from September 2020 to August 2022. Patients with a Harvey-Bradshaw Index of ≤4 were included and those who underwent intestinal resection were excluded. Bowel wall thickness and stratification and blood flow signal using superb microvascular imaging (SMI) were used to assess ultrasonography findings. SMI signals were categorized into 4 grades following the Limberg score. Receiver operating characteristic curves were constructed and the area under the curve was calculated to determine the LRG cutoff values for predicting active IUS findings and were compared with those of C-reactive protein. This study included 213 patients. The LRG cutoff values to predict active bowel wall thickness, loss of bowel wall stratification, and SMI of ≥1, ≥2, and 3 were 14.6 μg/mL, 14.6 μg/mL, 14.6 μg/mL, 14.6 μg/mL, and 16.9 μg/mL, respectively, with significantly higher areas under the curve in SMI of ≥1 and 3 than in C-reactive protein. The best LRG cutoff value for predicting active IUS findings was 14.6 μg/mL in patients with CD in clinical remission, suggesting that LRG is better than C-reactive protein for detecting active IUS findings in CD.

Novel Technique of Endoscopic Ultrasonography for the Differential Diagnosis of Gallbladder Lesions and Intraductal Papillary Mucinous Neoplasms: A Single-Center Prospective Study

Detective flow imaging endoscopic ultrasonography (DFI-EUS) is an innovative imaging modality that was developed to detect fine vessels and low-velocity blood flow without contrast agents. We evaluate its utility for the differential diagnosis of gallbladder lesions and intraductal papillary mucinous neoplasms (IPMNs). We enrolled patients who underwent DFI-EUS, e-FLOW EUS, and contrast-enhanced EUS for gallbladder lesions or IPMNs. The detection of vessels using DFI-EUS and e-FLOW EUS was compared with that via contrast-enhanced EUS and pathological findings. The vessel pattern was also categorized as regular or irregular. Of the 33 lesions included, there were final diagnoses of 13 IPMNs and 20 gallbladder lesions. DFI-EUS was significantly superior to e-FLOW EUS for discriminating between mural nodules and mucous clots and between solid gallbladder lesions and sludge using the presence or absence of vessel detection in lesions (p = 0.005). An irregular vessel pattern with DFI-EUS was a significant predictor of malignant gallbladder lesions (p = 0.002). DFI-EUS is more sensitive than e-FLOW-EUS for vessel detection and the differential diagnosis of gallbladder lesions and IPMNs. Vessel evaluation using DFI-EUS may be a useful and simple method for differentiating between mural nodules and mucous clots in IPMN, between solid gallbladder lesions and sludge, and between malignant and benign gallbladder lesions.

The value of conventional ultrasound combined with superb microvascular imaging and color Doppler flow imaging in the diagnosis of thyroid malignant nodules: a systematic review and meta-analysis

Purpose

To evaluate and compare the value of conventional ultrasound-based superb microvascular imaging (SMI) and color Doppler flow imaging (CDFI) in the diagnosis of malignant thyroid nodule by meta-analysis.

Methods

The literature included in the Cochrane Library, PubMed, and Embase were searched by using " superb microvascular imaging (SMI), color Doppler flow imaging (CDFI), ultrasound, thyroid nodules" as the keywords from inception through February 1, 2023. According to the inclusion and exclusion criteria, the clinical studies using SMI and CDFI to diagnose thyroid nodules were selected, and histopathology of thyroid nodules was used as reference standard. The diagnostic accuracy research quality assessment tool (QUADAS-2) was used to evaluate the quality of included literature, and the Review Manager 5.4 was used to make the quality evaluation chart. The heterogeneity test was performed on the literature that met the requirements, the combined sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were pooled, and a comprehensive ROC curve analysis was performed. Meta-DiSc version 1.4, StataSE 12, and Review Manager 5.4 software were used.

Results

Finally, 13 studies were included in this meta-analysis. A total of 815 thyroid malignant nodules were assessed. All thyroid nodules were histologically confirmed after SMI or CDFI. The combined sensitivity, specificity, PLR, NLR, DOR, and area under the SROC curve of SMI for the diagnosis of malignant thyroid nodules were 0.80(95%CI: 0.77-0.83), 0.79(95%CI: 0.77-0.82), 4.37(95%CI: 3.0-6.36), 0.23(95%CI: 0.15-0.35), 22.29(95%CI: 12.18-40.78), and 0.8944, respectively; the corresponding values of CDFI were 0.62(95%CI: 0.57-0.67), 0.81(95%CI: 0.78-0.85), 3.33(95%CI: 2.18-5.07), 0.41(95%CI: 0.27-0.64), 8.93(95%CI: 3.96-20.16), and 0.8498. Deek funnel pattern showed no significant publication bias.

Conclusion

The diagnostic efficiency of SMI for malignant thyroid nodules is better than CDFI, and SMI technology can provide significantly more information on vascularity, make up for the deficiency of CDFI, and has better clinical application value.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023402064.

Diagnostic Performance of Superb Microvascular Imaging in Differentiating Benign and Malignant Axillary Lymph Nodes

ABSTRACT

The aim was to evaluate the effectiveness of superb microvascular imaging (SMI) in axillary lymph nodes (LNs).Benign and malignant LNs diagnosed via histopathological examination constituted the study subgroups. In addition to grayscale findings for morphological evaluation, vascular patterns and appearance of internal vessels were analyzed by both power Doppler ultrasound (PDUS) and SMI. The number of vascular branches was counted, and a vascularity index (VI) was calculated by SMI.Fifty-two LNs with suspicious findings in terms of metastasis (33 malignant and 19 benign) were evaluated. Diagnostic accuracy according to vascular patterns was 82% for PDUS and 92% for SMI. In the presence of asymmetric cortical thickening, there was a significant difference between benign and malignant LNs in the number of vascular branches of both thin and thick cortical sides ( P < 0.01). Mean VI was significantly higher in the malignant group ( P < 0.05). In differentiating malignancy, when a cutoff VI value was set to 9%, sensitivity was 69.7%, and specificity was 63.2%.Evaluating the vascularity of axillary LNs by SMI is a useful tool in determining the potential of axillary metastasis, especially in the absence of typical sonographic findings. Superb microvascular imaging can beneficially be used to select the most suspicious LN and suspicious area of the LN to sample.

The feasibility of early response evaluation using superb microvascular imaging one day after transcatheter arterial chemoembolization for hepatocellular carcinoma

PURPOSE

The purpose of this study was to determine the feasibility of early Superb microvascular imaging (SMI) for prediction of the effect of HCC treatment after transcatheter arterial chemoembolization (TACE).

MATERIALS AND METHODS

A total of 96 HCCs (70 patients) treated with TACE between September 2021 and May 2022 were included in this study. SMI, Color Doppler imaging (CDI), and Power Doppler imaging (PDI) were performed the day after TACE for evaluation of intratumoral vascularity of the lesion using an Aplio500 ultrasound scanner (Toshiba Medical Systems, Corporation, Tochigi, Japan). Grading of the vascular presence was performed using a five-point scale. A dynamic CT image taken after 29-42 days was used for comparison of sensitivity, specificity, and accuracy for detection of tumor vascularity between SMI, CDI, and PDI. Univariate and multivariate analysis were performed for assessment of factors affecting intratumoral vascularity.

RESULTS

Fifty-eight lesions (60%) showed complete remission (CR) and 38 lesions (40%) showed partial response (PR) or no response at 29-42 days on Multi-detector Computed Tomography (MDCT) after TACE. SMI showed sensitivity of 86.84% for detection of intratumoral flow, which was significantly higher compared with that of CDI (10.53%, p < 0.001) and PDI (36.84%, p < 0.001). The results of multivariate analysis indicated that tumor size was a significant factor in detection of blood flow using the SMI technique.

CONCLUSION

Early SMI may be utilized as an adjunctive diagnostic test for evaluation of treated lesions after TACE, particularly when the location of the tumor is in an area of the liver where a suitable sonic window can be identified.

Evaluation of Surgeon-Performed Ultrasonography With or Without Contrast Enhancement vs Scintigraphy in Patients With Primary Hyperparathyroidism

Importance

Scintigraphy and ultrasonography are common imaging modalities for the preoperative localization of enlarged parathyroid glands in primary hyperparathyroidism. When comparing the 2 modalities, the benefits of ultrasonography in terms of convenience, patient comfort, duration, cost, and lack of radiation should be taken into account.

Objective

To investigate whether surgeon-performed ultrasonography, with or without contrast-enhanced ultrasonography (CEUS), is noninferior to scintigraphy for localizing pathological parathyroid glands in patients with primary hyperparathyroidism.

Design, Setting, and Participants

Prospective, paired, noninferiority cohort study performed at a high-volume tertiary referral center for parathyroidectomy with blinded examiners and a 6-month follow-up. Participants were adults (age ≥18 years) referred for parathyroidectomy due to primary hyperparathyroidism. Of 207 eligible patients, 35 were excluded, leaving 172 enrolled in the study. Inclusion lasted from September 2019 until February 2021. Follow-up ended in December 2021.

Exposures

99mTechnetium-pertechnetate/99mtechnetium-sestamibi subtraction scintigraphy with 99mtechnetium-sestamibi single-photon emission computed tomography/computed tomography, followed by surgeon-performed ultrasonography and CEUS.

Main Outcomes and Measures

The sensitivity of each imaging modality in localizing pathological parathyroid glands, calculated on a per-quadrant and a per-patient basis, respectively. The a priori noninferiority margin was a lower 95% confidence limit for the difference in sensitivity not falling below -10%.

Results

Out of 172 participants, 139 (80.8%) were women, the median (range) age was 65 (24-87) years, and the median (IQR) follow-up was 200.5 (181-280.25) days. Quadrant sensitivity (95% CI) was 70.9% (63.2%-78.5%) for ultrasonography, 68.4% (60.4%-76.5%) for ultrasonography plus CEUS, and 67.0% (60.0%-74.0%) for scintigraphy. The sensitivity difference (95% CI) compared with scintigraphy was 3.9% (-4.1% to 11.8%) for ultrasonography and 1.5% (-6.4% to 9.3%) for ultrasonography plus CEUS, establishing noninferiority for both modalities. Per-patient sensitivity was 81.4% (74.8%-86.9%) for ultrasonography and 79.1% (72.2%-84.9%) for both scintigraphy and ultrasonography plus CEUS. The sensitivity difference compared with scintigraphy was 2.3% (-6.8% to 11.4%) for ultrasonography and 0.0% (-9.1% to 9.1%) for ultrasonography plus CEUS, establishing noninferiority for both modalities.

Conclusions and Relevance

In this cohort study, conventional ultrasonography by an experienced parathyroid surgeon-sonographer was noninferior to scintigraphy and may constitute a valid first-line imaging modality in patients with primary hyperparathyroidism, even without the addition of CEUS. Further imaging should be reserved for cases that are equivocal or nonlocalizing on ultrasonography.

Diagnostic value of superb microvascular imaging and color doppler for thyroid nodules: A meta-analysis

Objective

Superb micro-vascular imaging (SMI) is a new noninvasive modality for the diagnosis of thyroid nodules. However, the performance of SMI in differentiating malignant and benign thyroid nodules has not been systematically evaluated. This meta-analysis was performed to assess the accuracy of SMI in diagnosing thyroid nodules.

Methods

PubMed, Cochrane Library, Embase, Web of Science, Sinomed, Scopus were searched. We recorded the characteristics of the included studies and assessed the quality of each study using the QUADAS-2 tool. The pooled sensitivity, specificity, positive likelihood ratio (LR), negative LR, diagnostic odds ratio (DOR), and area under the curve (AUC) were calculated. We also evaluated the publication bias.

Results

This meta-analysis included 10 studies with a total of 1083 thyroid nodules. The pooled the sensitivity, specificity, and positive and negative LR were 0.84, 0.86, 6.2, and 0.18, respectively. The DOR and AUC were 33 and 0.91, respectively. Heterogeneity existed between the included studies. No significant publication bias was observed.

Conclusion

Compared with CDFI, Superb micro-vascular imaging (SMI) has higher diagnostic sensitivity and specificity, better diagnostic efficiency, and could be used to diagnose benign and malignant nodules in the display of blood flow distribution capabilities of thyroid nodules; at the same time, Fagan plot showed that the SMI technique had a good clinical application value, and it could supplement the deficiencies of color Doppler imaging in the diagnosis of thyroid nodules.

Intraoperative shear-wave elastography and superb microvascular imaging contribute to the glioma grading

BACKGROUND

To explore the diagnostic value and feasibility of shear wave elastography and superb microvascular imaging in the grading diagnosis of glioma intraoperatively.

MATERIALS AND METHODS

Forty-nine patients with glioma were included in this study. B-mode ultrasonography, Young's modulus in shear-wave elastography (SWE) and vascular architecture in superb microvascular imaging(SMI) of tumor tissue and peritumoral tissue were analyzed. Receiver operating characteristic(ROC) curve analysis was used to evaluate the diagnostic effect of SWE. Logistic regression model was used to calculate the prediction probability of HGG diagnosis.

RESULTS

Compared with LGG, HGG was often characterized by peritumoral edema in B mode (P < 0.05). There was a significant difference in Young's modulus between HGG and LGG; the diagnostic threshold of HGG and LGG was 13.05 kPa, the sensitivity was 78.3%, and the specificity was 76.9%. The vascular architectures of the tumor tissue and peritumoral tissues of HGG and LGG were significantly different (P < 0.05). The vascular architectures of peritumoral tissue in HGG often characterized by distorted blood flow signals surrounding the tumor (14/26,53.8%); in the tumor tissue, HGG often presents as dilated and bent vessels(19/26,73.1%). The elasticity value of SWE and the tumor vascular architectures of SMI were correlated with the diagnosis of HGG.

CONCLUSION

Intraoperative ultrasound (ioUS), especially SWE, and SMI are beneficial for the differentiation of HGG and LGG and may help optimize clinical surgical procedures.

Quantitative Biomarkers Derived from a Novel Contrast-Free Ultrasound High-Definition Microvessel Imaging for Distinguishing Thyroid Nodules

Low specificity in current ultrasound modalities for thyroid cancer detection necessitates the development of new imaging modalities for optimal characterization of thyroid nodules. Herein, the quantitative biomarkers of a new high-definition microvessel imaging (HDMI) were evaluated for discrimination of benign from malignant thyroid nodules. Without the help of contrast agents, this new ultrasound-based quantitative technique utilizes processing methods including clutter filtering, denoising, vessel enhancement filtering, morphological filtering, and vessel segmentation to resolve tumor microvessels at size scales of a few hundred microns and enables the extraction of vessel morphological features as new tumor biomarkers. We evaluated quantitative HDMI on 92 patients with 92 thyroid nodules identified in ultrasound. A total of 12 biomarkers derived from vessel morphological parameters were associated with pathology results. Using the Wilcoxon rank-sum test, six of the twelve biomarkers were significantly different in distribution between the malignant and benign nodules (all p < 0.01). A support vector machine (SVM)-based classification model was trained on these six biomarkers, and the receiver operating characteristic curve (ROC) showed an area under the curve (AUC) of 0.9005 (95% CI: [0.8279,0.9732]) with sensitivity, specificity, and accuracy of 0.7778, 0.9474, and 0.8929, respectively. When additional clinical data, namely TI-RADS, age, and nodule size were added to the features, model performance reached an AUC of 0.9044 (95% CI: [0.8331,0.9757]) with sensitivity, specificity, and accuracy of 0.8750, 0.8235, and 0.8400, respectively. Our findings suggest that tumor vessel morphological features may improve the characterization of thyroid nodules.

Application value of shear-wave elastography combined with monochrome superb microvascular imaging in renal allograft chronic rejection

BACKGROUND

Conventional ultrasound (US), which include gray scale US and Doppler US, is the first-line imaging modality for the evaluation of renal allograft; however, conventional US indicators have limitations.

OBJECTIVE

To explore the application value of shear-wave elastography (SWE) combined with monochrome superb microvascular imaging (mSMI) in renal allograft chronic rejection (CR).

METHODS

From November 2021 to February 2022 in the Lanzhou University Second Hospital, the US features of 54 patients with renal allograft were retrospectively analyzed. Patients were categorized into two groups: stable group(n = 44) and CR group(n = 10), with clinical diagnosis as reference standard. The vascular index (VI) on mSMI and parenchymal stiffness were measured in the middle cortex of all renal allografts and receiver operating characteristic (ROC) curves were drawn to evaluate the feasibility of differentiation. Statistically significant US features and biochemical indicators such as creatinine were scored, and the results of the scores were analyzed by ROC curve.

RESULTS

The VI on mSMI of the stable group (49.5±2.0) was significantly greater than that of the CR group (33.8±5.9) (P = 0.028). There was a statistically significant difference in parenchymal stiffness between stable group (16.2kPa±1.2) and CR group (33.9kPa±6.6) (P = 0.027). The sensitivity was 90% and specificity was 81.8% of the scores in the differentiation of stable group from CR group (cut-off value, 2; P = 0.000).

CONCLUSION

SWE combined with mSMI may help differentiate stable renal allograft from renal allograft CR and have the potential application value in the diagnosis of renal allograft CR.

Multimodal ultrasound imaging: A method to improve the accuracy of diagnosing thyroid TI-RADS 4 nodules

Thyroid nodule is a common and frequently occurring disease in the neck in recent years, and ultrasound has become the preferred imaging diagnosis method for thyroid nodule due to its advantages of noninvasive, nonradiation, real-time, and repeatable. The thyroid imaging, reporting and data system (TI-RADS) classification standard scores suspicious nodules that are difficult to determine benign and malignant as grade 4, and further pathological puncture is recommended clinically, which may lead to a large number of unnecessary biopsies and operations. Including conventional ultrasound, ACR TI-RADS, shear wave elastography, super microvascular imaging, contrast enhanced ultrasound, "firefly," artificial intelligence, and multimodal ultrasound imaging used in combination. In order to identify the most clinically significant malignant tumors when reducing invasive operations. This article reviews the application and research progress of multimodal ultrasound imaging in the diagnosis of TI-RADS 4 thyroid nodules.

Ultrasound super-resolution imaging for the differential diagnosis of thyroid nodules: A pilot study

Objective

Ultrasound imaging provides a fast and safe examination of thyroid nodules. Recently, the introduction of super-resolution imaging technique shows the capability of breaking the Ultrasound diffraction limit in imaging the micro-vessels. The aim of this study was to evaluate its feasibility and value for the differentiation of thyroid nodules.

Methods

In this study, B-mode, contrast-enhanced ultrasound, and color Doppler flow imaging examinations were performed on thyroid nodules in 24 patients. Super-resolution imaging was performed to visualize the microvasculature with finer details. Microvascular flow rate (MFR) and micro-vessel density (MVD) within thyroid nodules were computed. The MFR and MVD were used to differentiate the benign and malignant thyroid nodules with pathological results as a gold standard.

Results

Super-resolution imaging (SRI) technique can be successfully applied on human thyroid nodules to visualize the microvasculature with finer details and obtain the useful clinical information MVD and MFR to help differential diagnosis. The results suggested that the mean value of the MFR within benign thyroid nodule was 16.76 ± 6.82 mm/s whereas that within malignant thyroid was 9.86 ± 4.54 mm/s. The mean value of the MVD within benign thyroid was 0.78 while the value for malignant thyroid region was 0.59. MFR and MVD within the benign thyroid nodules were significantly higher than those within the malignant thyroid nodules respectively (p < 0.01).

Conclusions

This study demonstrates the feasibility of ultrasound super-resolution imaging to show micro-vessels of human thyroid nodules via a clinical ultrasound platform. The important imaging markers, such as MVD and MFR, can be derived from SRI to provide more useful clinical information. It has the potential to be a new tool for aiding differential diagnosis of thyroid nodules.

Case series of mobile structures detected vividly by using superb microvascular imaging

Background

Superb microvascular imaging (SMI) is a new imaging technique that can reveal low-velocity blood flow without use of a contrast agent. SMI is based on an original algorithm and effectively removes tissue motion artifacts (clutter motion) from the background, thereby preserving visibility of low-velocity blood flow. SMI is expected to be useful for the evaluation of heart diseases, as well as blood vessels.

Case summary

Here, we report three cases in which a mobile structure in the heart or a blood vessel was detected easily by strong enhancement on SMI. In the heart, the entire mass was strongly enhanced by colour-SMI and had the appearance of 'a fire ball'. In the abdominal aorta and carotid artery, SMI captured a strongly enhanced echo image of a mass and revealed hyperechoic mobile plaque. It was hard to detect with the conventional echocardiography.

Discussion

It is important to detect mobile intravascular and intracardiac structures as they are risk factors of thrombosis. Echo images are often strongly affected by the skill of the examiner, the patient's body habitus, and the presence of intestinal gas; thus, it is often difficult to detect a small mass with conventional echocardiography. With the use of SMI, even small mobile structures can be displayed at high intensity in comparison with the surrounding blood flow. Therefore, the non-invasive SMI was useful for the detection of mobile intravascular and intracardiac structures. Our findings of the current report may lead to new developments in SMI for imaging in the cardiac region.

The application value of CDFI and SMI combined with serological markers in distinguishing benign and malignant thyroid nodules

PURPOSE

The purpose of this study is to explore the application value of CDFI and SMI combined with serological markers in distinguishing benign and malignant thyroid nodules.

METHOD

A total of 192 patients with thyroid nodules admitted to our hospital from July 2019 to December 2020 were selected as subjects. Color Doppler blood flow imaging (CDFI) and supermicro blood flow imaging (SMI) methods are used to detect the blood flow of patients and the levels of serum thyroglobulin antibody (TgAb), thyroid peroxidase antibody (TPOAb), and thyroid stimulating hormone (TSH). The receiver operating characteristic curve (ROC curve) was used to observe the sensitivity and specificity of serological markers for distinguishing benign and malignant thyroid nodules, and combined with CDFI and SMI to observe the sensitivity and specificity for distinguishing benign and malignant thyroid nodules.

RESULTS

The levels of TgAb, TPOAb and TSH in benign thyroid nodules were lower than those of the malignant group, and the difference was statistically significant (P < 0.01). There was no statistically significant difference between benign and malignant thyroid nodules in the presence or absence of the capsule and the presence or absence of vocal halo (P > 0.05), while the differences in the nodule morphology, boundary, internal echo and internal calcification were statistically significant (P < 0.01).

CONCLUSION

CDFI and SMI combined with serological index detection have higher value in the differential diagnosis of thyroid cancer, which can significantly improve the sensitivity and specificity of differential diagnosis.

Current understanding and future potential applications of cerebral microvascular imaging in infants

Microvascular imaging is an advanced Doppler ultrasound technique that detects slow flow in microvessels by suppressing clutter signal and motion-related artifacts. The technique has been applied in several conditions to assess organ perfusion and lesion characteristics. In this pictorial review, we aim to describe current knowledge of the technique, particularly its diagnostic utility in the infant brain, and expand on the unexplored but promising clinical applications of microvascular imaging in the brain with case illustrations.

Grayscale, subjective color Doppler, combined grayscale with subjective color Doppler in predicting thyroid carcinoma: a retrospective analysis

Introduction

Fine needle aspiration cytology is preferred for thyroid nodules preoperatively, but has disadvantages of false-negative and false-positive results.

Objective

To compare the diagnostic performance of grayscale ultrasound, subjective color Doppler ultrasound, and combined features of grayscale ultrasound and subjective color Doppler ultrasound in predicting thyroid carcinoma, using results of the fine needle aspiration cytology as the reference standard.

Methods

Data from gray-scale ultrasound images, subjective color Doppler ultrasound images, and the fine needle aspiration cytology of 325 nodules of 250 patients (age ≥ 18 years) were collected and analyzed. Hypo-echogenicity than adjacent strap muscle, micro-lobulated or irregular margins, micro- or mixed calcifications, and taller-than-wide shapes were considered as a suspicious malignant nodule in grayscale ultrasound. Marked vascularity was considered as a suspicious malignant nodule in color Doppler ultrasound. The Bethesda system for classification of thyroid nodules was used for cytopathology.

Results

With respect to the results of fine-needle aspiration cytology for detecting suspicious malignant nodules, for grayscale ultrasound, subjective color Doppler ultrasound, and combined gray-scale with subjective color Doppler ultrasound, sensitivities were 0.564, 0.600 and 0.691, respectively and accuracies were 0.926, 0.919 and 0.959, respectively. Suspicious malignant nodules detectability for grayscale ultrasound, subjective color Doppler ultrasound, and combined gray-scale with subjective color Doppler ultrasound were 0.09–0.56 diagnostic confidence, 0.08–0.61 diagnostic confidence, and 0.063–0.7 diagnostic confidence, respectively.

Conclusions

The combined gray-scale with subjective color Doppler ultrasound-guided fine-needle aspiration biopsies are recommended for the diagnosis of thyroid carcinoma.

Level of Evidence: III.

Advanced Ultrasound Techniques for Differentiation of Benign Versus Malignant Thyroid Nodules: A Review

ABSTRACT

Grayscale ultrasound (US) is decisive in stratifying which thyroid nodules benefit from fine-needle aspiration to evaluate for malignancy. Unfortunately, a significant percentage of nodules remain indeterminate.Herein, we review the clinical considerations and diagnostic accuracy of advanced US, Doppler US, contrast-enhanced US, and US elastography techniques in the evaluation of indeterminate nodules.We conclude that these techniques may be used in combination with grayscale US to improve the assessment of lesion vascularity and tissue property.

Added Value of Superb Microvascular Imaging and Virtual Touch Imaging Quantification in Assisting Thyroid Cancer Classification

This prospective study determined the value added by superb microvascular imaging (SMI) and Virtual Touch imaging quantification (VTIQ) to conventional ultrasonography in classifying malignant and benign thyroid nodules. One hundred eighty-three thyroid nodules (TNs) in 120 patients (112 benign and 71 malignant TNs) were evaluated. SMI revealed noticeable variance between benign and malignant TNs (p < 0.001). Malignant nodules tended to have rich vascularity (grade 3: 38/71, 53.5%) compared with benign nodules (grade 3: 33/112, 29.5%). There is a statistically significant difference between malignant and benign TNs with respect to shear-wave speed (SWS) values (all p values <0.001). The SWS mean, maximum and ratio of malignant nodules were 3.97 ± 1.34, 4.79 ± 1.70 and 1.25 ± 0.39, respectively. The SWS mean, maximum and ratio of benign nodules were 2.65 ± 0.42, 2.97 ± 0.46 and 1.15 ± 0.35, respectively. With respect to area under the curve values, the combined use of SMI or VTIQ improved the diagnostic performance of classifying malignant and benign TNs compared with that of ultrasonography alone. The combination of three modalities achieved the greatest area under the curve values (0.9811, 95% confidence interval: 0.95529-1.000), followed by US + VTIQ (0.9747, 0.94543-1.000), US + SMI (0.9032, 0.85345-0.95391) and ultrasonography (0.8291, 0.76417-0.89403).

Correlation and agreement between superb micro-vascular imaging and contrast-enhanced ultrasound for assessing radiofrequency ablation treatment of thyroid nodules: a preliminary study

Background

To evaluate the correlation and agreement between superb micro-vascular imaging (SMI) mode and the contrast-enhanced ultrasound (CEUS) mode for the ablative completeness and the volumes of ablation lesions to determine the clinical application value of SMI in follow-up after radiofrequency ablation.

Methods

From April 2020 to June 2020, two radiologists used SMI and CEUS mode to measure the volume of the ablation lesion. We use intra-class correlation coefficient (ICC), scatter plots and Bland–Altman plots to evaluate the correlation and agreement of the two techniques. In addition, intra- and inter-observer reliability in volume measurement of ablation lesions with SMI mode was assessed.

Results

SMI mode and CEUS mode have good agreement in the evaluation of ablative completeness. The ICC was 0.876 and 0.928 of reader A and reader B between SMI mode and CEUS mode in terms of ablation lesions volume measurement. There was a strong correlation between the two modes in both reader A and reader B (r_A = 0.808; r_B = 0.882). The ICC was 0.836 for the inter-observer reliability of SMI technique. The scatter plot showed a good linear relation (r = 0.715). In the Bland–Altman plot, 4.35% (1/23) of the points was outside the 95% limits of agreement. The ICC was 0.965 for the intra-observer reliability of SMI technique, the scatter plot also showed a strong linear correlation (r = 0.965). In the Bland–Altman plot, 8.70% (2/23) of the points was outside the 95% limits of agreement.

Conclusions

SMI and CEUS have good agreement and correlation in the ablation volume measurement. SMI technology is expected to be applied as an alternative to CEUS in the clinical follow-up of ablation lesions.

Analysis of vascularization in thyroid gland nodes with superb microvascular imaging (SMI) and CD34 expression histology: a pilot study

Background

The Doppler sonography technique known as "superb microvascular imaging" (SMI) is advancing sonographic micro vascularization imaging in various disciplines. In this study, we aimed to determine whether SMI could reliably reproduce the blood flow in thyroid nodes and whether malignancy could be diagnosed, based on vascularization properties. Immunhistochemical staining by CD34 and SMI where used to determine the vascularization of nodes in terms of quantified vascularization parameters gained by computational evaluation.

Methods

We used image analysis programs to investigate whether the quantitative value for vascularization strength in the thyroid node, measured with SMI, was correlated with the actual degree of vascularization, determined microscopically. We included 16 patients that underwent thyroid resections. We prepared thyroid gland tissue slices for immunohistochemistry and labelled endothelial cells with CD34 to visualize blood vessels microscopically. We used image analysis programs, ImageJ, to quantify SMI Doppler sonographic measurements and CellProfiler to quantify CD34 expression in histological sections. We evaluated the numeric values for diagnostic value in node differentiation. Furthermore, we compared these values to check for correlations.

Results

Among the 16 nodes studied, three harboured malignant tumours (18.75%): two papillary and one follicular carcinoma. Among the 13 benign lesions (81.25%), four harboured follicular adenomas. Malignant and benign nodes were not significantly different in sonographic (0.88 ± 0.89 vs. 1.13 ± 0.19; p = 0.2790) or immunohistochemical measurements of vascularization strength (0.05 ± 0.05 vs. 0.08 ± 0.06; p = 0.2260).

Conclusion

We found a positive, significant correlation (r = 0.55588; p = 0.0254) between SMI (quantitative values for vascularization strength) and immunohistochemistry (CD34 staining) evaluations of thyroid nodes.

A Novel Endoscopic Ultrasonography Imaging Technique for Depicting Microcirculation in Pancreatobiliary Lesions without the Need for Contrast-Enhancement: A Prospective Exploratory Study

Detective flow imaging endoscopic ultrasonography (DFI-EUS) provides a new method to image and detect fine vessels and low-velocity blood flow without using ultrasound contrast agents. The aim of this study was to evaluate the utility of DFI-EUS for pancreatobiliary lesions and lymph nodes. Between January 2019 and January 2020, 53 patients who underwent DFI-EUS, e-FLOW EUS, and contrast-enhanced EUS were enrolled. The ability of DFI-EUS and e-FLOW EUS to detect vessels was compared with that of contrast-enhanced EUS. This article describes the DFI technique along with our first experience of its use for vascular assessment of pancreatobiliary lesions. Vessels were imaged in 34 pancreatic solid lesions, eight intraductal papillary mucinous neoplasms (IPMNs), seven gall bladder lesions, and four swollen lymph nodes. DFI-EUS (91%) was significantly superior to e-FLOW EUS (53%) with respect to detection of vessels (p < 0.001) and for discrimination of mural nodules from mucous clots in IPMN and gallbladder lesions from sludge (p = 0.046). Thus, DFI-EUS has the potential to become an essential tool for diagnosis and vascular assessment of various diseases.

Performance of Contrast-Enhanced Ultrasound in Thyroid Nodules: Review of Current State and Future Perspectives

Ultrasound has been established as a baseline imaging technique for thyroid nodules. The main advantage of adding CEUS is the ability to assess the sequence and intensity of vascular perfusion and hemodynamics in the thyroid nodule, thus providing real-time characterization of nodule features, considered a valuable new approach in the determination of benign vs. malignant nodules. Original studies, reviews and six meta-analyses were included in this article. A total of 624 studies were retrieved, and 107 were included in the study. As recognized for thyroid nodule malignancy risk stratification by US, for acceptable accuracy in malignancy a combination of several CEUS parameters should be applied: hypo-enhancement, heterogeneous, peripheral irregular enhancement in combination with internal enhancement patterns, and slow wash-in and wash-out curve lower than in normal thyroid tissue. In contrast, homogeneous, intense enhancement with smooth rim enhancement and "fast-in and slow-out" are indicative of the benignity of the thyroid nodule. Even though overlapping features require standardization, with further research, CEUS may achieve reliable performance in detecting or excluding thyroid cancer. It can also play an operative role in guiding ablation procedures of benign and malignant thyroid nodules and metastatic lymph nodes, and providing accurate follow-up imaging to assess treatment efficacy.

The Role of CEUS in the Evaluation of Thyroid Cancer: From Diagnosis to Local Staging

Ultrasound often represents the first diagnostic step for thyroid nodule evaluation in clinical practice, but baseline US alone is not always effective enough to achieve thyroid nodule characterization. In the last decades new ultrasound techniques, such as CEUS, have been introduced to evaluate thyroid parenchyma as recommended by EFSUMB guidelines, for use in clinical research field, although its role is not yet clear. Several papers show the potential utility of CEUS in the differential diagnosis of benign and malignant thyroid nodules and in the analysis of lymph node involvement in neoplastic pathology. Therefore, we carried out an evaluation of the literature concerning the role of CEUS in three specific areas: the characterization of the thyroid nodule, the evaluation of minimally invasive treatment and loco-regional staging of the lymph node in proven thyroid cancer. According to evidence reported, CEUS can also play an operative role in nodular thyroid pathology as it is able to guide ablation procedures on thyroid nodule and metastatic lymph nodes, to assess the radicality of surgery, to evaluate disease relapse at the level of the margins of ablated regions and to monitor the clinical evolution of necrotic areas in immediate post-treatment setting.

Clinical value of SMI Combined with Low-Dose CT Scanning in differential diagnosis of Thyroid Lesions and Tumor Staging

Objectives

To investigate the clinical value of Superb Microvascular Imaging (SMI) combined with low dose CT scanning in differential diagnosis of thyroid lesions and tumor staging.

Methods

A total of 120 patients with thyroid nodules admitted to the Chinese PLA General Hospital from January 2017 to July 2020 were selected. Paired design was adopted in this study. SMI and SMI combined with low-dose CT scanning were respectively carried out to these patients. The results were judged by two senior imaging physicians and two senior sonographers respectively. And t-test, χ² test, Pearson correlation coefficient check and other methods were adopted to comparatively analyze the above two methods and the pathological results after operation or puncture.

Results

Compared with pathologic findings, the coincidence rate of SMI was 40%, and the coincidence rate of SMI combined with low dose CT scanning was 84%. The difference was significant (p=0.00); among the 120 thyroid nodule patients, 50 were diagnosed as malignant by pathological diagnosis, and 70 as benign; 27 malignant cases and 93 benign cases were detected by SMI; 48 malignant cases and 72 benign cases were detected by SMI combined with low dose CT scanning. The sensitivity and accuracy of the latter were significantly higher than those of the former, and the difference was statistically significant (p=0.00); the enhancement, edge sharpness and homogeneity of SMI increased with the increase of tumor malignancy, showing positive correlation property.

Conclusion

SMI combined with low dose CT scanning has a higher diagnostic coincidence rate. Its sensitivity and accuracy are significantly superior. With the increase of tumor malignancy, the enhancement and unhomogeneity of SMI increase, and the edge is more blurred. That suggests: with the increase of tumor malignancy, neovascularization in the tumor is more obvious and more unevenly distributed; the increase of edge blur indicates more obvious tumor infiltration. The method has considerable clinical value for predicting the malignancy of tumors.

Novel endoscopic ultrasonography imaging technique for visualizing microcirculation without contrast enhancement in subepithelial lesions: Prospective study

OBJECTIVES

Detective flow imaging for endoscopic ultrasonography (DFI?EUS) is a new imaging modality developed for detecting fine vessels without using ultrasound contrast agents. This study aimed to evaluate its utility by comparing it with a type of directional power Doppler (eFLOW) for subepithelial lesions (SELs).

METHODS

Between January 2019 and January 2020, 28 patients with SELs undergoing DFI?EUS and eFLOW?EUS were enrolled. DFI?EUS and eFLOW?EUS assessing the vascularity in SELs were compared in terms of the rates of identification of intratumoral vessels. We also investigated how large vessels were depicted in both modalities based on surgical specimens as well as the detection rates of intratumoral vessels in gastrointestinal stromal tumors (GISTs) and non?GISTs using either DFI?EUS or eFLOW?EUS.

RESULTS

Among 28 patients, 23 with pathological confirmation by EUS?guided fine?needle aspiration biopsy (EUS?FNAB) specimens were included. Of those 23 patients, the 10 who underwent surgical resection were selected for analysis. The rate of detection of intratumoral vessels in SELs was significantly higher on DFI?EUS (80%) than on eFLOW?EUS (30%) (P\xA0=\xA00.03). Comparison with surgical specimens revealed that detection rate for vessels with maximum size of less 1000\xA0μm was higher in DFI?EUS (66%) than that in eFLOW?EUS (0%). GIST patients had significantly higher positive rates (90%) of intratumoral vessels than non?GIST patients (31%) on DFI in 23 cases including EUS?FNAB specimens (P\xA0=\xA00.045).

CONCLUSIONS

Detective flow imaging?EUS is more sensitive for depicting intratumoral vessels than eFLOW?EUS. Evaluation of intratumoral vessels on DFI?EUS is useful for identifying GISTs without contrast agents.

The value of superb microvascular imaging (SMI) scoring assignment method in differentiating benign and malignant thyroid nodules by conventional ultrasound

PURPOSE

To explore the application value of SMI scoring assignment method combined with 2017 American College of Radiology (ACR) Thyroid Imaging, Reporting and Data System (TI-RADS) in differentiating benign and malignant thyroid nodules.

METHODS

According to the 2017 ACR TI-RADS classification, the enrolled nodules were divided into 3 points group, 4 points group, 5 points group, 6 points group and≥7 points group. The nodules were assigned scores according to the echocity of the nodules and the microvessels detected by SMI and their distribution patterns based on ACR TI-RADS. Accompany with the scores increased or decreased after assignment, the thyroid nodules were re-grouped.

RESULTS

The AUC after the scores assignment is better than before (Z = 3.881, P <  0.001). The specificity, positive predictive value and accuracy after score assigned are better than those of before (Z = 8.323, P <  0.001; Z = 8.619, P <  0.001; Z = 5.345, P <  0.001), there is no statistical difference in sensitivity before and after score assigned (Z = -0.513, P = 0.60), and the negative predictive value before assigned score is better than that of after (Z = -3.826, P <  0.001).

CONCLUSION

The diagnostic efficacy after scoring was better than that of before.

Assessment of neovascularization of carotid artery atherosclerotic plaques using superb microvascular imaging: a comparison with contrast-enhanced ultrasound imaging and histology

Background

This study aimed to investigate the usefulness of superb microvascular imaging (SMI), a novel non-contrast-enhanced ultrasound technique, in characterizing neovessels within carotid atherosclerotic plaques through comparison with contrast-enhanced ultrasound (CEUS) and histology.

Methods

Patients with carotid plaque were recruited and underwent SMI and CEUS ultrasound imaging of the carotid arteries. The maximum plaque thickness, length, and stenosis of each plaque were measured. Grade of the neovessels was determined by SMI and CEUS, respectively. Grade 0 was defined as no blood flow signal/microbubbles within plaques; grade 1 was defined as moderate blood flow signals/microbubbles confined to the shoulder and/or adventitial side of the plaque; and grade 2 was defined as extensive intraplaque signals/microbubbles. Patients with symptomatic carotid stenosis (stenosis ≥50%) or asymptomatic carotid stenosis (stenosis ≥70%) underwent endarterectomy, and plaque specimens were subjected to immunohistochemical analysis of CD31 expression. The neovessels were quantified by histology. The agreement of SMI with CEUS and histology in characterizing neovessels was analyzed using weighted Kappa statistic and Spearman's correlation analyses.

Results

Seventy-eight patients (mean age: 67.3±8.9 years old, 63 males) were recruited. Of these patients, 52 (66.7%) had a unilateral plaque and 26 (33.3%) had bilateral plaques in the carotid arteries. For the 104 carotid plaques detected, the mean plaque thickness and length were 4.3±1.1 and 18.8±6.6 mm, respectively. The prevalence of <50%, 50-69%, and ≥70% stenosis was 43.3%, 24.0%, and 32.7%, respectively. Excellent agreement was found between SMI and CEUS (κ=0.825 at the plaque level; κ=0.820 at the patient level) in evaluating the neovessel grade within the carotid plaques. Of the 25 patients who underwent carotid endarterectomy, a strong correlation (r=0.660, P<0.001) was found between SMI and histology in the evaluation of intraplaque neovessels. SMI had excellent scan-rescan (κ=0.857), intra-reader (κ=0.810), and inter-reader (κ=0.754) agreement in the assessment of intraplaque neovessels.

Conclusions

The SMI technique is capable of reliably characterizing neovessels within carotid atherosclerotic plaques and demonstrates good to excellent agreement with histology and CEUS.

Evaluation of parenchymal vascularity of the thyroid gland with vascularization index by color superb microvascular imaging in patients with Graves' disease

Aim of the study

To determine the parenchymal vascularity of the thyroid gland with color superb microvascular imaging in patients with Graves’ disease, and compare the vascularization index values with healthy subjects.

Materials and methods

The thyroid glands of 37 patients whose laboratory and clinical findings were consistent with Graves’ disease, and 40 asymptomatic subjects with normal laboratory values, were examined using color superb microvascular imaging. Measurements of the vascularization index were performed with a free region of interest which was drawn along the outer margin of the gland on the color superb microvascular imaging mode. The vascularization index values obtained in the Graves’ disease and control groups were compared. A correlation analysis was performed between the vascularization index values and laboratory and grayscale US parameters.

Results

The median vascularization index value of the thyroid parenchyma in patients with Graves’ disease was significantly higher than in the asymptomatic group [median (min–max); 12 (2.3–32.1) vs 5.04 (1.1–10.8), p <0.001]. When the cutoff value of the vascularization index is determined as 6.3, Graves’ disease can be diagnosed with 83.8% sensitivity and 70% specificity.

Conclusions

The vascularization index obtained with color superb microvascular imaging can be a quantitative indicator of parenchymal vascularity in the diagnosis of Graves’ disease, and serve as a supportive tool.

The Role of Superb Microvascular Imaging and Shear Wave Elastography in Differentiation of Thyroid Nodules from Intrathyroidal Ectopic Thymus in Children

BACKGROUND

Ectopic thymus could be located intrathyroidal, therefore fine ultrasound details are useful for this differentiation.

AIM

To investigate differences in stiffness and vascularity properties among thyroid nodules and intrathyroidal ectopic thymus (IET) by obtaining quantitative data in children.

PATIENTS AND METHODS

Twenty-seven thyroid nodules and 20 IET in children were evaluated in terms of vascularity index (VI) via superb microvascular imaging (SMI) and stiffness by shear wave elastography (SWE). Differences in the volume, VI, and SWE parameters of the lesions were assessed by using the Mann-Whitney U test. Association of the age, lesion volume, SWE, and VI parameters was investigated by using Spearman's correlation analysis. The optimal cut-off values for stiffness and vascularity in the differentiation of nodules from IET were calculated with ROC analysis.

RESULTS

The median (range) age of the participants with thyroid nodules and IET were 15.6 (10-18) years and 8.8 (3-14) years, respectively. The medians (range) VI of the IET and thyroid nodules were 4.7 (0.2-16) % and 23.8 (7.5-40)%, respectively. The median SWE values were 7.6 (4.4-9.5) kPa and 15.58 (8.5-23.4) kPa for IET and nodules, respectively. There have been highly significant differences among medians of volume, SWE, and VI values of the lesions. Significant positive correlations were found between VI and SWE parameters (p=0.001, r=0.64), and volume with VI (p=0.018, r=0.34) and SWE (p:0.001, r= 0.5). The diagnostic accuracies were 93%, 91% with the cut-off values as 9.2 kPa, 13% for the SWE and SMI, respectively. IETs were found to be less vascular and less stiff than thyroid nodules.

CONCLUSIONS

IETs could be easily and confidently differentiated from nodules using SWE and SMI quantifications. This discrimination prompts the reduction of unnecessary interventional procedures.

Efficacy of superb microvascular imaging of ultrasound for diagnosis of gallbladder lesion

BACKGROUND/PURPOSE

The diagnosis of gallbladder (GB) lesions is occasionally difficult. Recently, superb microvascular imaging (SMI) of ultrasound has been developed as a novel microvascular imaging technique. We evaluated the feasibility of SMI for the diagnosis of GB lesions and compared microvascular imaging between benign and malignant GB lesions.

METHODS

Twenty patients with GB-protruded lesions or wall thickening who underwent SMI from August 2015 to July 2017 were included in this retrospective study. The measured outcomes were the quality of microvascular imaging when compared between normal SMI (N-SMI) and contrast-enhanced SMI (CE-SMI), and the microvascular findings (vascularity, vascular morphology, presence of branching, and presence of caliber change) when compared between benign and malignant GB lesions.

RESULTS

The quality of microvascular imaging of CE-SMI was evaluated as better than that of N-SMI, showing a significant difference (P < .001). From the CE-SMI microvascular findings, the evaluation of vascular morphology and the presence of caliber change showed a significant difference between benign and malignant GB lesions (P = .005, P < .001).

CONCLUSIONS

The evaluation of GB lesions using SMI was feasible with a contrast agent. Vascular morphology and the presence of caliber change may help in the differential diagnosis of GB lesions.

The role of multimodal ultrasonic flow imaging in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules

Background

Color Doppler imaging (CDFI), contrast-enhanced ultrasound (CEUS), and superb micro-vascular imaging (SMI) are used to observe blood flow characteristics in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules. The ability of these techniques to distinguish benign from malignant nodules was investigated.

Methods

A total of 75 TI-RADS 4 nodules were examined using CDFI, SMI, and CEUS. The blood flow characteristics shown by the three methods were added to the current TI-RADS classification to establish a new TI-RADS classification. The value of the three methods and the diagnostic accuracy of the new and old TI-RADS classification were compared.

Results

SMI better captured type II flow in benign nodules and type III flow in malignant nodules relative to CDFI. Malignant nodules detected with CEUS manifested mainly with hypo-enhancement, whereas benign nodules showed iso- and hyper-enhancement. The areas under the receiver operating characteristic (ROC) curves (AUC) obtained through the aforementioned flow distribution models were 0.690 (CDFI), 0.840 (SMI), 0.910 (CEUS), and 0.903 (CEUS and SMI combined mode), respectively. The diagnostic value of CEUS was the highest. Joint inspection using SMI with CEUS showed certain advantages in sensitivity, although the overall accuracy was equal to that of CEUS alone. Except for CDFI, the AUC of the new TI-RADS classification was significantly higher than that of the old one. Perforating vessels and low enhancement were independent predictors of thyroid carcinoma.

Conclusions

Both SMI and CEUS visualized lower-velocity blood flow within TI-RADS 4 nodules. The new TI-RADS classification described here could improve diagnostic accuracy.

Assessment of thyroid gland vascularity with superb microvascular imaging in healthy children and its relationship with potential factors

Objectives To define thyroid gland vascularity index (VI) values in healthy children with the superb microvascular imaging (SMI) method and to assess whether or not there is a correlation with potential factors that may affect these values. Methods This prospective study included a total of 138 children, their ages varying from 3-17 years. Cases were divided into three subgroups according to age: 3-6, 7-12 and 13-17 years. Gender, age, height, weight, body mass index (BMI), thyroid-stimulating hormone (TSH) and free thyroxine (fT4) values were recorded. Volume and SMI measurements were performed with a 14 L5 mHz linear transducer. VI measurements were performed in the transverse and longitudinal planes and correlation with basic descriptive data was researched. Results Mean age was 11.14 ± 3.34 years and BMI was 19.95 ± 4.92. VI values were 4.59 ± 2.34 in the right lobe and 4.23 ± 2.73 for the left lobe, with no significant difference identified. There were no significant differences in mean VI for all parenchyma regarding gender and age groups. While there was no correlation identified with mean VI for all parenchyma with TSH and fT4, there was, however, a negative correlation with BMI. Conclusions Reference VI values for normal thyroid glands in healthy children and adolescents were defined with the SMI method. There was no correlation between the VI values and age, gender, volume, TSH and fT4 values, while there was a negative significant correlation with BMI.

Contrast-enhanced ultrasound for needle biopsy of thoracic lesions

Two-dimensional ultrasound (US) and color doppler flow imaging are associated with certain limitations in the preprocedural evaluation and design of the puncture path for biopsies of thoracic lesions, such as a poorly defined boundary between the tumor and the atelectatic lesions in central lung cancer with atelectasis. Contrast-enhanced ultrasound (CEUS) can be valuable in the preoperative evaluation of the biopsy site and in increasing the accuracy of the biopsy. The present study investigated the value of clinical application of CEUS in US-guided core needle biopsy (US-CNB) in improving the diagnostic accuracy in thoracic lesions. A total of 120 patients with first-stage thoracic lesions from the Affiliated Tumor Hospital of Guangxi Medical University who underwent US-CNB were recruited and randomnly assigned to a conventional US group (n=66) and a CEUS group (n=54). All patients underwent preoperative evaluation and US-guided puncture of thoracic lesions. The intergroup differences in sonographic features, biopsy duration, biopsy success rate and complications were assessed. The CEUS group had a higher rate of detection of necrotic tissue (40.7% vs. 16.7%; χ²=8.633; P=0.003) and change of initial puncture path (48.1%) compared with the US group. In central lung cancer with atelectasis, the ability to distinguish between tumor and atelectasis was higher in the CEUS group compared with the conventional US group (31.5 vs. 7.6%; χ²=11.336; P=0.001). In addition, the CEUS group had a higher puncture success (96.3 vs. 80.3%; χ²=6.946; P=0.008) and a lower complication rate (3.7% vs. 18.2%; χ²=6.041; P=0.014) compared with the US group. CEUS can identify necrotic areas and occult tumors within atelectatic lung tissue and can be used for guiding puncture biopsy of thoracic lesions to improve the diagnostic accuracy with greater comparative clinical utility than conventional US. Pre-biopsy CEUS is especially useful for patients undergoing repeated US-CNB and those with hypovascular lesions, atelectasis or necrosis.

Ultrasound 2020 - Diagnostics & Therapy: On the Way to Multimodal Ultrasound: Contrast-Enhanced Ultrasound (CEUS), Microvascular Doppler Techniques, Fusion Imaging, Sonoelastography, Interventional Sonography

BACKGROUND

 Ultrasound as a non-ionizing imaging procedure is one of the most important diagnostic procedures in everyday clinical practice. The technology is widely used. Due to constant technical innovations, sonographic procedures, such as contrast-enhanced ultrasound (CEUS), sonoelastography, new microvascular Doppler modalities and, as an example of interventional procedures, sonographically controlled microwave ablation (MWA), are becoming increasingly important in diagnostic imaging and interventional medicine alongside CT and MRI. However, this also requires greater expertise, specialization and qualification on the part of users.

METHOD

 This review article provides information about the range of technical innovations in ultrasound in recent years and describes the underlying technology, the clinical applications, and their diagnostic value. These are presented in the context of the current literature, explaining their advantages and disadvantages and their clinical value.

RESULTS AND CONCLUSION

 Contrast-enhanced ultrasound (CEUS), microvascular Doppler modalities, fusion imaging and elastography complement B-scan ultrasound and conventional Doppler procedures for various problems. Microwave ablation (MWA) has a firm place as an ablative procedure for local tumor therapy in different organ systems and can be performed under ultrasound guidance. Thanks to new developments, the possibilities of ultrasound are now greater than ever. Knowledge of the technology, indications, and possible applications of newer procedures is essential for adequate patient care.

KEY POINTS

  · Contrast-enhanced ultrasound (CEUS) allows an increase in sensitivity and specificity in the assessment of parenchymal lesions.. · CEUS allows the microperfusion to be visualized and quantified. For larger vessels, CEUS is an important instrument in diagnosing endoleak after stenting.. · Microvascular Doppler techniques with clutter suppression algorithms allow a more accurate representation of the smallest vessels than regular color or power Doppler.. · Elastography of the liver in diffuse hepatopathies is a noninvasive diagnostic tool to exclude higher grade fibrosis/cirrhosis.. · Microwave ablation (MWA) also offers sonographically controlled ablation of tumors..

CITATION FORMAT

· Kloth C, Kratzer W, Schmidberger J et al. Ultrasound 2020 - Diagnostics & Therapy: On the Way to Multimodal Ultrasound: Contrast-Enhanced Ultrasound (CEUS), Microvascular Doppler Techniques, Fusion Imaging, Sonoelastography, Interventional Sonography . Fortschr Röntgenstr 2021; 193: 23 - 32.

Comparison of three ultrasonographic examinations on the synovial membrane vascularity of RA patients

Rheumatoid arthritis (RA) is a systemic autoimmune disease involving multiple joints and often involves the small joints, and the lesions are symmetric, invasive, and disabling. Synovial blood flow in patients with RA was compared using color Doppler flow imaging (CDFI), power Doppler ultrasound (PDUS), and superb microvascular imaging (SMI) to determine the application value of SMI in synovial vasospasm of knee joints. The blood flow signals of the suprapatellar recess in the knee joints of 41 RA patients (49 knees) were measured prior to undergoing total knee arthroplasty (TKA), recorded, and graded by CDFI, PDUS, and SMI. The results of the three ultrasound examination methods were compared and analyzed. The SMI grading was compared with the pathologic grade of the synovial membrane. Forty-one patients underwent 49 TKAs. The display rate of the synovial blood flow signal was 93.9% in the CDFI model, 97.9% in the PDUS model, and 100% in the SMI model. There were statistically significant differences in the results between the three ultrasound examination methods (H_C = 11.84, P < 0.05). The consistency of the SMI and pathologic grades of synovial membranes was better than the other methods (kappa = 0.639, P < 0.05). Compared with CDFI and PDUS, the signal of synovia flow detected by SMI was significantly higher in RA patients. SMI classification had a better consistency with the pathologic grade, and SMI has application value in assessing the activity of RA.

Impact of imaging cross-section on visualization of thyroid microvessels using ultrasound: Pilot study

Non-invasive, contrast-free microvascular imaging of human thyroids can be potentially beneficial in reducing the large number of benign biopsies of suspicious nodules. However, motion incurred by thyroid due to its proximity to the pulsating carotid artery significantly impacts the visualization of blood flow in small vessels. Singular value based spatiotemporal clutter filtering (SVD-STF) improves the performance of tissue rejection in the presence of motion. However, despite effective clutter filtering, motion in thyroid imaging can impact coherent integration of the Doppler ensemble and degrade the visualization of the underlying vasculature. Recently studies have demonstrated that motion correction using 2D normalized cross-correlation based speckle tracking can address this issue, however, only in-plane motion can be tracked and corrected. Given the natural anatomical orientation of the rigid trachea, thyroid and the pulsating carotid artery, we hypothesize that imaging of thyroid microvessels may be more reliable in the longitudinal view than in the transverse. Specifically, distal presence of rigid trachea can limit out-of-plane motion in the longitudinal view. We tested this hypothesis on 48 acquisitions obtained from 24 thyroid patients having at least one suspicious nodule. In each patient, ultrasound images of the thyroid were acquired in both longitudinal and transverse views. Compounded plane-wave imaging was used to acquire the ultrasound images at high frame-rate, which is important for contrast-free small vessel blood flow imaging. Thyroid motion was tracked using 2D normalized cross-correlation based speckle tracking. Tissue clutter was rejected using singular value decomposition based spatiotemporal clutter filtering. The clutter-filtered Doppler ensemble was motion corrected prior to slow-time power Doppler integration. Signal-to-noise and contrast-to-noise ratios were computed to assess the improvement in quality of the power Doppler images. Out-of-plane motion was detected by estimating normalized ensemble cross-correlation coefficient. The results demonstrated that motion associated with the thyroid due to the carotid artery was primarily in the lateral direction, which could be estimated and corrected using 2D speckle tracking. However, the motion in the transverse view displayed increased speckle decorrelation. The average ensemble cross-correlation coefficient of the thyroid ultrasound images were significantly higher (p < 0.05) in the longitudinal view than in the transverse view. The largest improvement in SNR and CNR of the estimated PD images upon motion correction was observed in the longitudinal view (12.95 ± 3.76 dB and 16.48 ± 4.6 dB) than in the transverse view (3.72 ± 0.894 dB and 6.217 ± 1.689 dB). These preliminary results show that motion encountered by the thyroid due to carotid pulsations can be effectively tracked and corrected in the longitudinal view relative to transverse, which is important for reliably visualizing the underlying blood flow.