Additional Value of Superb Microvascular Imaging for Thyroid Nodule Classification with the Thyroid Imaging Reporting and Data System

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.

Superb microvascular imaging (SMI) and elastosonography in thyroid nodule: diagnostic value in a real-time cohort

PURPOSE

In clinical practice, thyroid nodules are classified according to TI-RADS by B-mode and color-flow Doppler study. The aim of the study is to evaluate the possible added value of Superb microvascular imaging (SMI) and elastosonography in the stratification of malignancy risk of thyroid nodules.

METHODS

All patients with thyroid nodules who were candidates for needle aspiration were enrolled. Experienced operators performed a standard examination with TI-RADS calculation, followed by SMI and elastosonography on the nodules. The needle aspiration outcome was used as the gold standard. Statistical analysis calculated the ROC curves of the techniques applied individually and serially.

RESULTS

In this prospective study, we analysed 260 nodules, found in 251 patients (mean age 58.6 yo ± 14). 11.2% were TI-RADS 1, 18.9% TI-RADS 2, 41.1% TI-RADS 3, 28.1% TI-RADS 4, and 0.8% TI-RADS 5. The SMI technique showed an AUC of 0.57 (95% CI 0.49; 0.66) while elastosonography had an AUC of 0.58 (95% CI 0.49; 0.67) when used individually. SMI together with elastosonography had AUC of 0.62 (95% CI 0.52; 0.71). TI-RADS had AUC of 0.67 (95% CI 0.59; 0.75). SMI and elastosonography applied together with TI-RADS had AUC of 0.69 (95% CI 0.61; 0.77).

CONCLUSION

In the real-world cohort of patients, the SMI technique and elastosonography slightly increase the AUC of TI-RADS. Taken individually, SMI and elastosonography do not have a very strong AUC.

Effectiveness of microvascular flow imaging for radiofrequency ablation in recurrent thyroid cancer: comparison with power Doppler imaging

OBJECTIVES

To compare microvascular flow imaging (MVFI) and power Doppler ultrasonography imaging (PDUS) for detecting intratumoral vascularity in recurrent thyroid cancer both before and after radiofrequency ablation (RFA).

METHODS

This retrospective study included 80 patients (age, 57 ± 12 years; 54 women) with 110 recurrent tumors who underwent RFA between January 2021 and June 2023. A total of 151 PDUS and MVFI image sets were analyzed (85 pre-RFA, 66 post-RFA). Two readers assessed vascularity on the images using a four-point scale with a 2-week interval between PDUS and MVFI to estimate inter-reader agreement. Intra-reader agreement was determined by reinterpreting images in reverse order (MVFI-PDUS) after a 1-month gap. Additionally, diagnostic performance for identifying viable tumors after RFA was assessed in 44 lesions using thyroid-protocol CT as a reference standard.

RESULTS

MVFI demonstrated higher vascular grades than PDUS, both before (reader 1: 3.04 ± 1.15 vs. 1.93 ± 1.07, p < 0.001; reader 2: 3.20 ± 0.96 vs. 2.12 ± 1.07, p < 0.001) and after RFA (reader 1: 2.44 ± 1.28 vs. 1.67 ± 1.06, p < 0.001; reader 2: 2.62 ± 1.23 vs. 1.83 ± 0.99, p < 0.001). Inter-reader agreement was substantial (κ = 0.743) and intra-reader agreement was almost perfect (κ = 0.840). MVFI showed higher sensitivity (81.5%-88.9%) and accuracy (84.1%-86.4%) than PDUS (sensitivity: 51.9%, p < 0.01; accuracy: 63.6-70.5%, p < 0.04), without sacrificing specificity.

CONCLUSION

MVFI was superior to PDUS for assessing intratumoral vascularity and showed good inter- and intra-reader agreement, highlighting its clinical value for assessing pre-RFA vascularity and accurately identifying post-RFA viable tumors in recurrent thyroid cancer.

CLINICAL RELEVANCE STATEMENT

Microvascular flow imaging (MVFI) is superior to power-Doppler US for assessing intratumoral vascularity; therefore, MVFI can be a valuable tool for assessing vascularity before radiofrequency ablation (RFA) and for identifying viable tumors after RFA in patients with recurrent thyroid cancer.

KEY POINTS

The value of microvascular flow imaging (MVFI) for evaluating intratumoral vascularity is unexplored. MVFI demonstrated higher vascular grades than power Doppler US before and after ablation. Microvascular flow imaging showed higher sensitivity and accuracy than power Doppler US without sacrificing specificity.

A Comparative Study of Two Radiomics-Based Blood Flow Modes with Thyroid Imaging Reporting and Data System in Predicting Malignancy of Thyroid Nodules and Reducing Unnecessary Fine-Needle Aspiration Rate

RATIONALE AND OBJECTIVES

We aimed to compare superb microvascular imaging (SMI)-based radiomics methods, and contrast-enhanced ultrasound (CEUS)-based radiomics methods to the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) for classifying thyroid nodules (TNs) and reducing unnecessary fine-needle aspiration biopsy (FNAB) rate.

MATERIALS AND METHODS

This retrospective study enrolled a dataset of 472 pathologically confirmed TNs. Radiomics characteristics were extracted from B-mode ultrasound (BMUS), SMI, and CEUS images, respectively. After eliminating redundant features, four radiomics scores (Rad-scores) were constructed. Using multivariable logistic regression analysis, four radiomics prediction models incorporating Rad-score and corresponding US features were constructed and validated in terms of discrimination, calibration, decision curve analysis, and unnecessary FNAB rate.

RESULTS

The diagnostic performance of the BMUS + SMI radiomics method was better than ACR TI-RADS (area under the curve [AUC]: 0.875 vs. 0.689 for the training cohort, 0.879 vs. 0.728 for the validation cohort) (P < 0.05), and comparable with BMUS + CEUS radiomics method (AUC: 0.875 vs. 0.878 for the training cohort, 0.879 vs. 0.865 for the validation cohort) (P > 0.05). Decision curve analysis showed that the BMUS+SMI radiomics method could achieve higher net benefits than the BMUS radiomics method and ACR TI-RADS when the threshold probability was between 0.13 and 0.88 in the entire cohort. When applying the BMUS+SMI radiomics method, the unnecessary FNAB rate reduced from 43.4% to 13.9% in the training cohort and from 45.6% to 18.0% in the validation cohorts in comparison to ACR TI-RADS.

CONCLUSION

The dual-modal SMI-based radiomics method is convenient and economical and can be an alternative to the dual-modal CEUS-based radiomics method in helping radiologists select the optimal clinical strategy for TN management.

Diagnostic performance of the gallbladder reporting and data system combined with color doppler flow imaging for gallbladder cancer in the Asian population

Purpose

Evaluating the performance of the Gallbladder Reporting and Data System (GB-RADS) combined with Color Doppler Flow Imaging (CDFI) for the diagnosis of gallbladder wall thickening disease in an Asian population.

Methods

In this study, the lesions were classified and the actual incidence rate of malignant tumors was calculated for each GB-RADS category, following the guidelines provided by GB-RADS. To evaluate the diagnostic performance of GB-RADS and GB-RADS combined with CDFI, we plotted Receiver Operator Characteristic (ROC) curves. The sensitivity (SE), specificity (SP), positive predictive value (PPV), negative predictive value (NPV), and accuracy (AC) were also calculated. Inter-observer agreement (IRA) between the two observers was assessed using Kappa values.

Results

The incidence of malignancy risk for GB-RADS 2, 3, 4, and 5 was 9%, 12.5%, 72.2%, and 100%. The AUC for GB-RADS was 0.855 (95% CI: 0.800-0.900), with a sensitivity of 82.5%, a specificity of 84.6%, and an accuracy of 83.8%. The AUC of GB-RADS combined with CDFI was 0.965 (95% CI: 0.930-0.985), with a sensitivity of 96.2%, a specificity of 94.6%, and an accuracy of 95.2%. The AUC, sensitivity, specificity, and accuracy of GB-RADS combined with CDFI for diagnosing gallbladder malignancy were higher than those of GB-RADS alone, and the differences were statistically significant (all P < 0.05). The IRA was excellent between the two observers (Kappa = 0.870).

Conclusions

GB-RADS combined with CDFI demonstrated excellent diagnostic accuracy when it comes to distinguishing various diseases that caused gallbladder wall thickening in the Asian population, which has good clinical value and can improve the detection rate of malignant tumors in patients with gallbladder wall thickening.

Diagnostic efficiency among Eu-/C-/ACR-TIRADS and S-Detect for thyroid nodules: a systematic review and network meta-analysis

Background

The performance in evaluating thyroid nodules on ultrasound varies across different risk stratification systems, leading to inconsistency and uncertainty regarding diagnostic sensitivity, specificity, and accuracy.

Objective

Comparing diagnostic performance of detecting thyroid cancer among distinct ultrasound risk stratification systems proposed in the last five years.

Evidence acquisition

Systematic search was conducted on PubMed, EMBASE, and Web of Science databases to find relevant research up to December 8, 2022, whose study contents contained elucidation of diagnostic performance of any one of the above ultrasound risk stratification systems (European Thyroid Imaging Reporting and Data System[Eu-TIRADS]; American College of Radiology TIRADS [ACR TIRADS]; Chinese version of TIRADS [C-TIRADS]; Computer-aided diagnosis system based on deep learning [S-Detect]). Based on golden diagnostic standard in histopathology and cytology, single meta-analysis was performed to obtain the optimal cut-off value for each system, and then network meta-analysis was conducted on the best risk stratification category in each system.

Evidence synthesis

This network meta-analysis included 88 studies with a total of 59,304 nodules. The most accurate risk category thresholds were TR5 for Eu-TIRADS, TR5 for ACR TIRADS, TR4b and above for C-TIRADS, and possible malignancy for S-Detect. At the best thresholds, sensitivity of these systems ranged from 68% to 82% and specificity ranged from 71% to 81%. It identified the highest sensitivity for C-TIRADS TR4b and the highest specificity for ACR TIRADS TR5. However, sensitivity for ACR TIRADS TR5 was the lowest. The diagnostic odds ratio (DOR) and area under curve (AUC) were ranked first in C-TIRADS.

Conclusion

Among four ultrasound risk stratification options, this systemic review preliminarily proved that C-TIRADS possessed favorable diagnostic performance for thyroid nodules.

Systematic review registration

https://www.crd.york.ac.uk/prospero, CRD42022382818.

Using preoperative ultrasound vascularity characteristics to estimate medullary thyroid cancer

BACKGROUND

The early diagnosis of medullary thyroid carcinoma (MTC) is still a challenge in clinical practice. Based on ultrasound features, many MTC cases without suspicious characteristics are not categorized as high risk for malignancy. This study was designed to comprehensively investigate the ultrasonic features of MTC on ultrasound and help identify thyroid nodules with a high risk of MTC.

METHODS

Between 2017 and 2023, we retrospectively reviewed 116 consecutive thyroid nodules with a histologic diagnosis of MTC who had undergone preoperative ultrasound examination. According to the ultrasonic criteria for risk classification, nodules were classified as "ultrasound-high suspicious" (h-MTC) and "ultrasound-low suspicious" (l-MTC). Using the same database, a tumour size- and risk evaluation-matched control group comprising 62 lesions was randomly selected to compare the vascularity features of l-MTC disease.

RESULTS

We identified 85 h-MTC nodules (73.3%) and 31 l-MTC nodules (26.7%). For patients with l-MTC disease, 22/31 (71.0%) of the lesions were followed up for a period before fine needle aspiration (FNA) or surgery. We observed more penetrating branching vascularity in the l-MTC group than in the benign nodule group (23/31, 74.2% vs. 5/59, 4.8%, P < 0.001). We also showed that more CHAMMAS IV patterns (central blood flow greater than perinodular flow) (87.1% vs. 32.3%, P < 0.001)) and CHEN IV patterns (penetrating vascularity) (100% vs. 25.8%, P < 0.001) were found in l-MTC than benign nodules.

CONCLUSIONS

Vascularity features can help differentiate l-MTC from benign nodules; moreover, we report a novel sonographic vascularity pattern of l-MTC disease, penetrating branching vascularity. The utilization of vascularity features will help to identify MTC among nodules with low-intermediate suspicion by ultrasound risk classification to ensure appropriate clinical management.

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.

Vascularity depicted by contrast-enhanced ultrasound predicts recurrence of papillary thyroid cancer

PURPOSE

Although angiogenesis is crucial for the occurrence and development of solid tumors, the prognostic value of vascularity remains unclear in papillary thyroid cancer (PTC), due to the lack of effective techniques to evaluate vascularity. Contrast-enhanced ultrasound (CEUS) is an effective technique to evaluate vascularity. This study aimed to investigate whether vascularity depicted by CEUS was associated with structural recurrence in classic PTC.

METHODS

512 consecutive patients who underwent total thyroidectomy and central lymph node dissection for classic PTC larger than 1 cm between January 2015 and December 2018 and who were followed up for 12 months or longer were retrospectively enrolled. For this study, iso- and hyperenhancement were considered hypervascularity, whereas hypovascularity referred to hypoenhancement. Kaplan-Meier cumulative event curves for structural recurrence were compared using the log-rank test. The multivariate Cox proportional hazard regression analysis was used to estimate hazard ratios (HRs) of hypervascularity depicted by CEUS for structural recurrence.

RESULTS

61 (11.9 %) of 512 patients had structural recurrence. Hypervascular PTCs had a shorter recurrence-free survival rate than hypovascular PTCs (P < 0.001). In the multivariate analysis, hypervascularity (HR, 2.069; 95 % confidence interval [CI]: 1.087, 3.937), larger size (HR, 1.279; 95 % CI: 1.011, 1.618), multifocality (HR, 1.976; 95 % CI: 1.150, 3.396), extrathyroidal extension (HR, 2.276; 95 % CI: 1.026, 5.046), and lymph node metastasis (HR, 3.631; 95 % CI: 1.515, 8.701) were independently associated with structural recurrence.

CONCLUSION

Hypervascularity depicted by CEUS was independently associated with structural recurrence in patients with classic PTC.

Diagnostic Value of AngioPLUS Microvascular Imaging in Thyroid Nodule Diagnosis Using Quantitative and Qualitative Vascularity Grading

This study investigated the diagnostic value of the Angio Planewave Ultrasensitive (AngioPLUS) Doppler ultrasound in improving the efficacy of grey scale ultrasound in thyroid nodule diagnosis. The EU TIRADS was used for the grey scale ultrasound assessment of 94 thyroid nodules. conventional Doppler and AngioPLUS Doppler ultrasound images were evaluated using qualitative vascularity grading, where predominant central vascularity indicated malignancy-suspicion, and quantitative regional vascularity assessment, where predominant peripheral vascularity using a ratio vascularity index (RVI) of > 1 indicated benign disease. Diagnostic performance outcomes of sole and combination approaches were calculated based on final pathologic results. Using sole EU TIRADS and AngioPLUS + power Doppler imaging (APDI) based on qualitative vascularity and RVI, the results were a sensitivity of 83.3% vs. 83.3 vs. 66.7% and a specificity of 50% vs. 81.3% vs. 73.4, respectively. EU TIRADS combined with APDI significantly improved the specificity using both qualitative vascularity and RVI assessment approaches (84.4% and 81%, respectively, p < 0.05); and slightly reduced the sensitivity (76.7% and 58.1%). For cytologically-equivocal thyroid nodules, the combination approach using qualitative vascularity assessment outperformed the EU TIRADS (sensitivity: both were 88.9%; specificity: 77.4% vs. 38.7%, p < 0.05; and AUROC: 0.83 vs. 0.62, p < 0.05). APDI combined with EU TIRADS is diagnostically efficient in stratifying thyroid nodules, particularly cytologically-equivocal nodules.

The clinical application of ultrasonography with superb microvascular imaging-a review

Superb microvascular imaging (SMI) is among the latest doppler ultrasound methods. It uses an advanced clutter filter to eliminate artifacts caused by breathing, movement and retains the low-speed blood signals in microvessels. The great advantage of SMI is that it can intuitively detect very slow blood signals in microvessels, providing clinicians with more significant information about flow distribution in the target area. Therefore, it is speculated that SMI has important application value. The purpose of this article is to outline the application of SMI in different parts of the body.

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.

Clinical Applications of Superb Microvascular Imaging in the Superficial Tissues and Organs: A Systematic Review

Superb microvascular imaging (SMI) is an innovative Doppler technique for vascular examination. It uses an intelligent algorithm that efficiently separates low-speed flow signals from motion artifacts so that it can assess microvessels and the vessel distribution in detail. This article reviews the clinical applications of SMI in the disorders of superficial tissues and organs including thyroid nodules, breast tumors and lymph node diseases etc. More information of diseases that are closely associated with angiogenesis can be shown by SMI than other noninvasive examinations. Although some limitations exist, this safe and convenient technique is becoming acceptable and would play a more important role in disease diagnosis and therapeutic responses evaluation.

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.

Superb Microvascular Imaging in Assessment of Synovitis and Tenosynovitis in Juvenile Idiopathic Arthritis

ABSTRACT

The aim of this study is to evaluate the diagnostic utility of superb microvascular imaging (SMI) in assessment of synovitis/tenosynovitis in juvenile idiopathic arthritis in comparison to power Doppler ultrasound. Thirty juvenile idiopathic arthritis cases with active clinical findings and ultrasound features of effusion and/or tenosynovitis were further imaged with power Doppler and SMI. For classification of synovial inflammation, a semiquantitative scale (4 points) adopted by Outcome Measures in Rheumatology was used.A total of 35 knee, 2 hip, 2 ankle, 2 wrist, 2 elbow joints, and 6 flexor hallucis longus/tibialis posterior tenosynovitis were assessed. In knee joint, power Doppler and SMI scales were the same for 23 (65.7%) joints, SMI upgraded scale from 0 to 2 in single joint (2.9%); 1 to 2 (14.3%) in 5 joints; and 2 to 3 (17.1%) in 6 joints. For other joints, power Doppler and SMI scales were the same for 5 (62.5%) joints. Superb microvascular imaging upgraded scale from 1 to 2 (25%) in 2 joints and 1 to 3 (12.5%) in a single joint. For flexor hallucis longus/tibialis posterior tenosynovitis, power Doppler and SMI scales were the same for two cases (33.3%). Superb microvascular imaging upgraded scale from 0 to 2 in two cases (33.3%); and 2 to 3 (33.3%) in 2 cases. There was no case of SMI scale downgraded compared with power Doppler scale.Superb microvascular imaging is a feasible technique in the assessment of synovial inflammation and tenosynovitis in juvenile idiopathic arthritis. Superb microvascular imaging has higher sensitivity compared with power Doppler ultrasound in depiction of increased vascularity.

Diagnostic utility of superb microvascular imaging in depiction of corkscrew collaterals in Buerger's disease

PURPOSE

To evaluate the corkscrew collaterals in Buerger's disease by superb microvascular imaging (SMI) and power Doppler ultrasonography (PDU).

METHODS

We evaluated with SMI and PDU 14 patients with Buerger's disease in whom corkscrew collaterals had been identified on digital subtraction angiography (DSA). Corkscrew collaterals were classified on DSA and PDU based on their size and morphology.

RESULTS

A total of 17 vascular regions of collateral vessel formation were assessed. Based on DSA classification, there were three cases of type I collaterals (arterial diameter of >2 mm with large helical pattern), seven cases of type III collaterals (arterial diameter of 1-1.5 mm with small helical pattern), and seven cases of type IV collaterals (arterial diameter of <1 mm with tiny helical pattern). On PDU, all type I collaterals on DSA appeared as "large snake" images, all type III collaterals on DSA appeared as "small snake" images, and all type IV collaterals on DSA appeared as dots. SMI imaging, both in color and monochrome mode, provided superior demonstration of the continuity of the vessel of large or small "snake" images. In cases appearing as dot pattern on PDU, color SMI was able to show continuity of the flow signal as a helical pattern.

DISCUSSION

SMI is a promising new Doppler imaging technique that is superior to conventional power Doppler imaging in depiction and identification of corkscrew collaterals in Buerger's disease.

Imaging based flowchart for gallbladder polyp evaluation

BACKGROUND

Preoperative differentiation between neoplastic and nonneoplastic gallbladder polyps, and the subsequent indication for cholecystectomy remains a clinical dilemma. The current 1 cm size threshold for neoplasia is unspecific. The aim of this study was to improve diagnostic work-up for gallbladder polyps using sonographic and MRI characteristics of neoplastic and nonneoplastic polyps.

METHODS

A prospective, exploratory study including patients undergoing cholecystectomy for gallbladder polyp(s) was conducted. Patients underwent targeted transabdominal ultrasound (TAUS) and MRI. Outcomes were sensitivity and specificity for polyp diagnosis, and the radiological characteristics of neoplastic and nonneoplastic polyp types. Histopathology after cholecystectomy was used as reference standard.

RESULTS

Histopathology demonstrated gallbladder polyps in 20/27 patients (74%): 14 cholesterol polyps, three adenomyomatosis, two adenomas and one gastric heterotopia. Sensitivity of polyp identification were 72% (routine TAUS) and 86% (targeted TAUS and MRI). Both adenomas were identified as neoplastic on targeted TAUS and MRI. Sonographic presentation as multiple, pedunculated polyps, either heterogeneous or with hyperechoic foci, or as single polyps containing cysts were limited to nonneoplastic polyps. On MRI hyperintense polyps on T1-weighted image were cholesterol polyps. An adenoma with high-grade dysplasia showed foci of decreased ADC values. We propose a checklist for polyp evaluation by targeted TAUS and a flowchart for radiological work-up of gallbladder polyps.

CONCLUSIONS

The presented checklist and flowchart could aid diagnostic work-up for gallbladder polyps compared to current routine ultrasound, by elimination of nonneoplastic polyps and ultimately improve treatment decision for patients with gallbladder polyps.

Conventional ultrasound characteristics, TI-RADS category and shear wave speed measurement between follicular adenoma and follicular thyroid carcinoma

The purpose of the study was to explore the differences of conventional ultrasound characteristics, thyroid imaging reporting and data system (TI-RADS) category and shear wave speed (SWS) measurement between follicular adenoma (FA) and follicular thyroid carcinoma (FTC). Twenty-eight FTCs and 67 FAs proven by surgery were retrospectively included for analysis. Conventional ultrasound and point-shear wave elastography (p-SWE) were performed in all of the included patients. The ultrasound features, American Thyroid Association (ATA) TI-RADS category and American College of Radiology (ACR) TI-RADS category, SWS measurement were compared between the two groups. Receiver operating characteristic (ROC) curve was performed and area under ROC curve (AUC) was obtained for significant features. There were no statistical differences in mean age (46.9±15.7years vs. 48.6±13.6years, P = 0.639), gender (9 males, 32.1% vs. 18 males, 29.0%, P = 0.766) and mean diameter (28.3±16.2 mm vs. 33.8±11.9 mm, P = 0.077) between FTCs and FAs. Hypoechogenicity, lobulated or irregular margin, macrocalcification were more common in FTCs than FAs (all P < 0.05). Mean SWS of FTCs (2.29±0.64 m/s) was slightly higher than that of FAs (1.94±0.68 m/s) (P = 0.023). The AUCs were 0.655, 0.744, and 0.744 with the cut-off SWS≥1.89 m/s, ACR TI-RADS category 4 and intermediate suspicion of ATA TI-RADS category. The sensitivity and AUC were 82.1% and 0.812 with combined ultrasound features of hypoechogenicity, lobulated or irregular margin and macrocalcification. In Conclusion, SWS measurement and TI-RADS categories were useful for the identification of FTCs from FAs.

Ultrasonographic Demonstration of the Tissue Microvasculature in Children: Microvascular Ultrasonography Versus Conventional Color Doppler Ultrasonography

Microvascular ultrasonographic imaging is the most recent and unique Doppler ultrasound technique. It uses an advanced clutter filter that can remove clutter artifacts and preserve the low-velocity microvascular flow signal. The potential advantages of microvascular ultrasonography are its superiority in detection and visualization of the small blood vessels in tissues, providing radiologists with more information on the vascular structures. Therefore, it has shown particular value in the clinical fields. The aim of this study was to provide microvascular ultrasonographic images for the tissue microvasculature, including the brain, thyroid gland, kidney, urinary bladder, small bowel, ovary, testis, lymph node, and hemangiomas in children, focusing on the comparison with conventional color Doppler ultrasonographic images.

Role of Superb Microvascular Imaging in Differentiating Between Malignant and Benign Solid Breast Masses

INTRODUCTION

The purpose of this study was to evaluate the diagnostic performance of superb microvascular imaging (SMI) in breast lesions.

MATERIALS AND METHODS

Eighty-five solid breast lesions were studied with color Doppler flow imaging (CDFI), power Doppler imaging (PDI), monochromatic SMI (mSMI), and contrast-enhanced ultrasonography (CEUS). The penetrating vessels (PVs) and microvascular morphologic and distribution features of the breast tumors were evaluated for each modality.

RESULTS

The diagnostic accuracies of CDFI, PDI, mSMI, and CEUS were calculated and compared. Surgical pathologic analysis showed 47 benign and 38 malignant lesions. Compared with CDFI and PDI, mSMI and CEUS detected more PVs in breast lesions. The microvascular architecture showed significant differences between benign and malignant lesions. Benign lesions mainly displayed avascular, line-like, and branch-like patterns, and malignant lesions tended to display root hair-like and crab claw-like patterns. mSMI and CEUS identified more root hair-like and crab claw-like patterns in malignant lesions than CDFI and PDI. The sensitivity, negative predictive value, and accuracy of mSMI findings in diagnosing malignancy based on PVs and vascular patterns were both higher than those of CDFI and PDI.

CONCLUSIONS

mSMI is equal to CEUS and superior to CDFI and PDI in identifying microvascular and discriminating malignant and benign breast masses.

Diagnostic Performance of Four Ultrasound Risk Stratification Systems: A Systematic Review and Meta-Analysis

Background: Several ultrasound (US)-based risk stratification systems have been increasingly used for the optimal management of thyroid nodules. However, there are considerable discrepancies across these systems. This study aimed to summarize and compare the category-based diagnostic performance in the detection of thyroid cancer of different US-based risk stratification systems from four societies: the American College of Radiology-Thyroid Imaging Reporting and Data System (ACR-TIRADS), the American Thyroid Association (ATA), the Korean Thyroid Association/Korean Society of Thyroid Radiology (KTA/KSThR; K-TIRADS), and the European Thyroid Association (EU-TIRADS). Methods: MEDLINE/PubMed and EMBASE databases were searched to identify original articles investigating the category-based diagnostic performance according to at least one of the following guidelines: ACR-TIRADS, ATA, K-TIRADS, and EU-TIRADS. Pooled sensitivity and specificity were calculated using a bivariate random-effects model. A subgroup analysis on nodules of 1 cm or larger and a meta-regression analysis to identify factors associated with the diagnostic performance were performed. Results: A total of 29 articles including 33,748 thyroid nodules met the eligibility criteria and were included in the analysis. For ACR-TIRADS, the pooled sensitivity and specificity were, respectively, 66% and 91% for category 5 and 95% and 55% for category 4 or 5. For ATA, the pooled sensitivity and specificity were, respectively, 74% and 88% for category 5 and 91% and 64% for category 4 or 5. For K-TIRADS, the pooled sensitivity and specificity were, respectively, 55% and 95% for category 5 and 89% and 64% for category 4 or 5. For EU-TIRADS, the pooled sensitivity and specificity were, respectively, 82% and 90% for category 5 and 96% and 52% for category 4 or 5. Study location, proportion of female patients and malignant nodules, and study design were associated with study heterogeneity. Conclusions: The overall diagnostic performance of the four US-based risk stratification systems was comparable.

Accuracy of thyroid imaging reporting and data system category 4 or 5 for diagnosing malignancy: a systematic review and meta-analysis

OBJECTIVES

To determine the accuracies of the American College of Radiology (ACR)-thyroid imaging reporting and data systems (TIRADS), Korean (K)-TIRADS, and European (EU)-TIRADS for diagnosing malignancy in thyroid nodules.

METHODS

Original studies reporting the diagnostic accuracy of TIRADS for determining malignancy on ultrasound were identified in MEDLINE and EMBASE up to June 23, 2019. The meta-analytic summary sensitivity and specificity were obtained for TIRADS category 5 (TR-5) and category 4 or 5 (TR-4/5), using a bivariate random effects model. To explore study heterogeneity, meta-regression analyses were performed.

RESULTS

Of the 34 eligible articles (37,585 nodules), 25 used ACR-TIRADS, 12 used K-TIRADS, and seven used EU-TIRADS. For TR-5, the meta-analytic sensitivity was highest for EU-TIRADS (78% [95% confidence interval, 64-88%]), followed by ACR-TIRADS (70% [61-79%]) and K-TIRADS (64% [58-70%]), although the differences were not significant. K-TIRADS showed the highest meta-analytic specificity (93% [91-95%]), which was similar to ACR-TIRADS (89% [85-92%]) and EU-TIRADS (89% [77-95%]). For TR-4/5, all three TIRADS systems had sensitivities higher than 90%. K-TIRADS had the highest specificity (61% [50-72%]), followed by ACR-TIRADS (49% [43-56%]) and EU-TIRADS (48% [35-62%]), although the differences were not significant. Considerable threshold effects were noted with ACR- and K-TIRADS (p ≤ 0.01), with subject enrollment, country of origin, experience level of reviewer, number of patients, and clarity of blinding in review being the main causes of heterogeneity (p ≤ 0.05).

CONCLUSIONS

There was no significant difference among these three international TIRADS, but the trend toward higher sensitivity with EU-TIRADS and higher specificity with K-TIRADS.

KEY POINTS

• For TIRADS category 5, the meta-analytic sensitivity was highest for the EU-TIRADS, followed by the ACR-TIRADS and the K-TIRADS, although the differences were not significant. • For TIRADS category 5, K-TIRADS showed the highest meta-analytic specificity, which was similar to ACR-TIRADS and EU-TIRADS. • Considerable threshold effects were noted with ACR- and K-TIRADS, with subject enrollment, country of origin, experience level of reviewer, number of patients, and clarity of blinding in review being the main causes of heterogeneity.