Shear wave elastography in the diagnosis of breast non-mass lesions: factors associated with false negative and false positive results. Eur Radiol. 2017;27:3788-3798. [PMID: 28168373 DOI: 10.1007/s00330-017-4763-6]

Enhancing malignancy prediction in thyroid nodules: A multimodal ultrasound radiomics approach in TI-RADS category 4 lesions

PURPOSE

To explore the diagnostic value of intralesional and perilesional radiomics based on multimodal ultrasound (US) images in predicting the malignant ACR TIRADS 4 thyroid nodules (TNs).

METHODS

A total of 297 cases of TNs in patients who underwent preoperative thyroid grayscale US and shear wave elastography (STE) were enrolled (training cohort: n = 150, internal validation cohort: n = 77, external validation cohort: n = 70). Regions of interests (ROIs) were delineated on grayscale US images and STE images, and then an isotropic expansion of 1.0, 1.5, 2.0, 2.5, and 3.0 mm was applied. Predictive models were established using recursive feature elimination-support vector machines (RFE-SVM) based on radiomics features calculated by random forest.

RESULTS

The perilesional ROI1.5mm expansion achieved the highest area under curve (AUC) (AUC: 0.753 for grayscale US, 0.728 for STE; 95% confidence interval (CI): 0.664-0.743, 0.684-0.739, respectively). The joint model had the highest AUC values of 0.936 in the training dataset, 0.926 in internal dataset, and 0.893 in external dataset. The calibration curve showed good consistency and the decision curve indicated a greater clinical net benefit of the joint model.

CONCLUSION

Joint model containing perilesional radiomics (1.5 mm) had significant value in predicting the malignant ACR TIRADS 4 TNs.

Combining Potential Strain Elastography and Radiomics for Diagnosing Breast Lesions in BI-RADS 4: Construction and Validation a Predictive Nomogram

RATIONALE AND OBJECTIVES

To develop a nomogram by integrating B-mode ultrasound (US), strain ratio (SR), and radiomics signature (RS) effectively differentiating between benign and malignant lesions in the Breast Imaging Reporting and Data System (BI-RADS) 4.

MATERIALS AND METHODS

We retrospectively recruited 709 consecutive patients who were assigned a BI-RADS 4 and underwent curative resection or biopsy between 2017 and 2022. US images were collected before surgery. A RS was developed through a multistep feature selection and construction process. Histology findings served as the gold standard. Univariate and multivariate regression analysis were employed to analyze the clinical and US characteristics and identify variables for developing a nomogram. The calibration and discrimination of the nomogram were conducted to evaluate its performance.

RESULTS

The study included a total of 709 patients, with 497 in the training set and 212 in the validation set. In the training set, the B-mode US had an AUC of 0.84 (95% confidence interval [CI], 0.80, 0.87). The SR demonstrated an AUC of 0.78 (95% CI, 0.74, 0.82), while the RS showed an AUC of 0.85 (95% CI, 0.81, 0.88). Notably, the nomogram exhibited superior performance compared to the conventional US, SR, and RS (AUC=0.93, both p < 0.05, as per the Delong test). The clinical usefulness of the nomogram was favorable.

CONCLUSION

The calibrated nomogram can be specifically designed to predict the malignancy of breast lesions in the BI-RADS 4 category.

Can shear wave elastography be utilized as an additional tool for the assessment of non-mass breast lesions?

INTRODUCTION

We aimed to describe shear wave elastography parameters of non-mass lesions of the breast and to assess the measures of diagnostic accuracy of shear wave elastography in the differentiation of non-mass lesions compared with conventional ultrasound, using histopathologic results as the reference standard.

METHODS

This retrospective study included breast ultrasound-detected non-mass lesions with a confirmed pathologic diagnosis during a two-year study period. B-mode ultrasound and shear wave elastography were performed for all lesions before biopsy. Ultrasound features, shear wave elastography parameters (mean elasticity and maximum stiffness color), as well as Breast Imaging-Reporting and Data System categories were recorded for each lesion. Measures of diagnostic accuracy of ultrasound and ultrasound + shear wave elastography were also assessed.

RESULTS

From a total of 567 breast lesions requiring core-needle biopsy, 49 (8.6%) were considered as non-mass lesions. Based on histopathologic reports, 32 patients (65.3%) had non-high-risk benign lesions, five (10.2%) had high-risk benign lesions, five (10.2%) had ductal carcinoma in situ, and seven (14.3%) had invasive carcinoma. There was no significant difference in patients' age and palpability between benign and malignant lesions (p = 0.16 and p = 0.12, respectively). Mean elasticity values and Breast Imaging-Reporting and Data System categories were significantly higher among malignant lesions compared with benign non-mass lesions (both p < 0.001). Furthermore, the addition of shear wave elastography to grayscale ultrasound increased the specificity, positive predictive value, and diagnostic accuracy.

CONCLUSION

The complementary use of shear wave elastography with conventional ultrasound might help in the differentiation of non-mass breast lesions and has the potential to decrease the frequency of unnecessary biopsies performed for benign non-mass lesions.

The lesion detection efficacy of deep learning on automatic breast ultrasound and factors affecting its efficacy: a pilot study

OBJECTIVES

The aim of this study was to investigate the detection efficacy of deep learning (DL) for automatic breast ultrasound (ABUS) and factors affecting its efficacy.

METHODS

Females who underwent ABUS and handheld ultrasound from May 2016 to June 2017 (N = 397) were enrolled and divided into training (n = 163 patients with breast cancer and 33 with benign lesions), test (n = 57) and control (n = 144) groups. A convolutional neural network was optimized to detect lesions in ABUS. The sensitivity and false positives (FPs) were evaluated and compared for different breast tissue compositions, lesion sizes, morphologies and echo patterns.

RESULTS

In the training set, with 688 lesion regions (LRs), the network achieved sensitivities of 93.8%, 97.2% and 100%, based on volume, lesion and patient, respectively, with 1.9 FPs per volume. In the test group with 247 LRs, the sensitivities were 92.7%, 94.5% and 96.5%, respectively, with 2.4 FPs per volume. The control group, with 900 volumes, showed 0.24 FPs per volume. The sensitivity was 98% for lesions > 1 cm³, but 87% for those ≤1 cm³ (p < 0.05). Similar sensitivities and FPs were observed for different breast tissue compositions (homogeneous, 97.5%, 2.1; heterogeneous, 93.6%, 2.1), lesion morphologies (mass, 96.3%, 2.1; non-mass, 95.8%, 2.0) and echo patterns (homogeneous, 96.1%, 2.1; heterogeneous 96.8%, 2.1).

CONCLUSIONS

DL had high detection sensitivity with a low FP but was affected by lesion size.

ADVANCES IN KNOWLEDGE

DL is technically feasible for the automatic detection of lesions in ABUS.

Diagnostic performance of elastography for breast non-mass lesions: A systematic review and meta-analysis

PURPOSE

This systematic review and meta-analysis aimed to evaluate the diagnostic performance of ultrasound elastography in the differentiation of benign and malignant breast non-mass lesions (NMLs).

METHODS

PubMed, Cochrane Library, and Embase databases were searched for eligible studies up to end of June 2021. The diagnostic performance of elastography for NMLs was investigated using pooled sensitivity and specificity, likelihood ratio, diagnostic odds ratio (DOR), post-test probability, and the area under hierarchical summary receiver operating characteristic curve (HSROC).

RESULTS

Eleven studies involving 812 NMLs (malignant 414) were included. The pooled sensitivity, specificity, DOR, positive likelihood ratio, and negative likelihood of elastography for the differentiation of benign and malignant breast NMLs were 79% (95 %CI: 71-85), 86% (95 %CI: 79-91), 23.32 (95 %CI: 13.38-40.66), 5.67 (95 %CI: 3.79-8.47), and 0.24 (95 %CI: 0.17-0.34), respectively. No significant publication bias existed. The area under the HSROC curve was 90% (95 %CI: 87-92). Fagan plots demonstrated good clinical utility. However, substantial heterogeneity existed. Country, measurement index, and number of lesions served as potential sources of heterogeneity.

CONCLUSIONS

The results of this study suggest that elastography has high diagnostic accuracy in differentiating between malignant and benign NMLs. Elastography can be a feasible and non-invasive tool for breast NMLs.

Ultrasonography predicts the results of labial salivary gland biopsy in patients with suspected Sjögren's syndrome: a matrix risk model

Objective:

Although a positive result of labial salivary gland biopsy (LSGB) is critical for the diagnosis of Sjögren’s syndrome, rheumatologists prefer assessing the non-invasive objective items and hope to learn the predicted probability of positive LSGB before referring patients with suspected Sjögren’s syndrome to receive biopsy. This study aimed to explore the predictive value of combined B-mode ultrasonography (US) and shear-wave elastography (SWE) examination on LSGB results.

Methods:

A derivation cohort and later a validation cohort of patients with suspected Sjögren’s syndrome were recruited. All participants received clinical assessments, B-mode US and SWE examination on bilateral parotid and submandibular glands before LSGB. Positive LSGB was defined by a focus score ⩾1 per 4 mm² of glandular tissue.

Results:

In the derivation cohort of 91 participants, either the total US scores or the total SWE values of four glands significantly distinguished patients with positive LSGB from those with negative results (area under the curve (AUC) = 0.956, 0.825, both p < 0.001). The positive predictive value (PPV) was 100% in patients with total US scores ⩾9 or with total SWE values ⩾33 kPa. The negative predictive value (NPV) was 100% in patients with total US scores <5, but 68% in patients with total SWE values <27 kPa. A matrix risk model was derived based on the combination of total US scores and total SWE values. Patients can be stratified into high, moderate, and low risk of positive LSGB. In the validation cohort of 52 participants, the PPV was 94% in the high-risk subpopulation and the NPV was 93% in the low-risk subpopulation.

Conclusion:

A novel matrix risk model based on the combined B-mode US and SWE examination can help rheumatologists to make a shared decision with suspected Sjögren’s syndrome patients on whether the invasive procedure of LSGB should be performed.

Effect of Calcifications on Shear-Wave Elastography in Evaluating Breast Lesions

This study aimed to investigate the effect of calcifications on shear-wave elastography in evaluating breast lesions. We retrospectively reviewed ultrasound images of 673 breast lesions and compared the elasticity between lesions with and without calcifications in three subgroups: benign lesions, in situ carcinomas and invasive carcinomas. Breast lesions were confirmed histologically (n = 401) or by follow-up images for more than 2 y (n = 272). Calcifications were present in 25.3% (170/673) of the lesions. The E_mean values with and without calcifications, respectively, were as follows: 62.8 and 29.8 kPa in benign lesions (p = 0.000), 114.6 and 52.8 kPa in in situ carcinomas (p = 0.037) and 171.9 and 146.4 kPa in invasive carcinomas (p = 0.018). The presence of calcifications significantly increased the E_mean of breast lesions. Shear-wave elastography should be carefully interpreted in benign lesions with calcifications and in situ carcinomas without calcifications.

Automated Breast Ultrasound: Interobserver Agreement, Diagnostic Value, and Associated Clinical Factors of Coronal-Plane Image Features

Objective

To evaluate the interobserver agreement, diagnostic value, and associated clinical factors of automated breast ultrasound (ABUS) coronal features in differentiating breast lesions.

Materials and Methods

This study enrolled 457 pathologically confirmed lesions in 387 female (age, 46.4 ± 10.3 years), including 377 masses and 80 non-mass lesions (NMLs). The unique coronal features, including retraction phenomenon, hyper- or hypoechoic rim (continuous or discontinuous), skipping sign, and white wall sign, were defined and recorded. The interobserver agreement on image type and coronal features was evaluated. Furthermore, clinical factors, including the lesion size, distance to the nipple or skin, palpability, and the histological grade were analyzed.

Results

Among the 457 lesions, 296 were malignant and 161 were benign. The overall interobserver agreement for image type and all coronal features was moderate to good. For masses, the retraction phenomenon was significantly associated with malignancies (p < 0.001) and more frequently presented in small and superficial invasive carcinomas with a low histological grade (p = 0.027, 0.002, and < 0.001, respectively). Furthermore, continuous hyper- or hypoechoic rims were predictive of benign masses (p < 0.001), whereas discontinuous rims were predictive of malignancies (p < 0.001). A hyperechoic rim was more commonly detected in masses more distant from the nipple (p = 0.027), and a hypoechoic rim was more frequently found in large superficial masses (p < 0.001 for both). For NMLs, the skipping sign was a predictor of malignancies (p = 0.040).

Conclusion

The coronal plane of ABUS may provide useful diagnostic value for breast lesions.

Evaluation of internal and shell stiffness in the differential diagnosis of breast non-mass lesions by shear wave elastography

BACKGROUND

The diagnostic specificity of conventional ultrasound for breast non-mass lesions (NMLs) is low at approximately 21%-43%. Shear wave elastography (SWE) can distinguish benign from malignant lesions by evaluating the internal and peripheral stiffness. SWE has good reproducibility and high diagnostic efficacy. However, there are very few independent studies on the diagnostic value of SWE in breast NMLs.

AIM

To determine the value of SWE in the differential diagnosis of breast NMLs.

METHODS

This study enrolled a total of 118 patients with breast NMLs who underwent SWE examinations in the Beijing Shijitan Hospital Affiliated to Capital Medical University and The Second Hospital of Shandong University from January 2019 to January 2020. The internal elastic parameters of the lesions were recorded, including maximum (Emax), mean (Emean) and minimum elastic values and the standard deviation. The following peripheral parameters were noted: Presence of a “stiff rim” sign; Emax, and Emean elasticity values within 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm from the edge of NMLs. The receiver operating characteristic curve of each parameter was drawn, and the areas under the curve were calculated.

RESULTS

Emax, Emean and elastic values, and the standard deviation of the internal elastic values in malignant NMLs were significantly higher than those in benign NMLs (P < 0.05). The percentage with the “stiff rim” sign in malignant NMLs was significantly higher than that in the benign group (P < 0.05), and Emax and Emean at the shell of 1 mm, 1.5 mm, 2 mm, 2.5 mm and 3 mm in the malignant group were all higher than those in the benign group (P < 0.05). Of the surrounding elasticity values, Emax of the shell at 2.5 mm in malignant NMLs had maximum areas under the curve of 0.900, and the corresponding sensitivity and specificity were 94.57% and 85.86%, respectively.

CONCLUSION

The “stiff rim” sign and multiple quantitative elastic values within and around the lesion had good diagnostic performance in the differential diagnosis of breast NMLs. Emax in peripheral tissue had better diagnostic efficiency than other parameters.

Value of shear wave elastography in the diagnosis and evaluation of cervical cancer

The aim of the present study was to explore the value of shear wave elastography (SWE) in the differential diagnosis of cervical disease and to evaluate the infiltration of cervical cancer. A total of 40 inpatients with cervical cancer, 40 inpatients with cervical benign lesion and 40 healthy volunteers encountered between October 2014 and January 2017 were enrolled. All patients and volunteers underwent conventional ultrasound (US) and SWE examinations. The malignancy and the size (including long, tranverse and anteroposterior diameter) of the lesion were assessed on US. The elastic score, strain ratio, shear wave speed (SWS) and the size of lesions were determined on SWE. Infiltration of the uterus and vaginal vault were also evaluated on US and SWE. The SWS values of cervical cancers, cervical benign lesions and normal cervixes groups were compared. The results suggested that the optimal cut-off elasticity score for predicting cervical cancers was 3 points. The strain ratio between the cervical cancers and the cervical benign lesions exhibited a significant difference (P<0.01). The mean value of SWS for cervical cancers was significantly higher than that of cervical benign lesions and normal cervix (P<0.05). Regarding the lesion size and volume, SWE and pathological measurements were larger than those determined by US (P<0.05 for each). The lesion volume on SWE and pathological measurements exhibited no significant difference (P>0.05). Compared to the pathological diagnosis of focal infiltration of uterus and vaginal vault, the diagnostic accuracy of SWE was higher than that of US. In conclusion, SWE may be used to differentiate between cervical benign lesions and cervical cancers. The elastic score, strain ratio and SWS of cervical cancers were higher than those of cervical benign lesions. Furthermore, SWE is able to evaluate the infiltration of cervical cancer.

2-D Shear Wave Elastography for Focal Lesions in Liver Phantoms: Effects of Background Stiffness, Depth and Size of Focal Lesions on Stiffness Measurement

The aim of this study was to determine the factors influencing stiffness and conspicuity of focal lesions in deep organs by focusing on target properties using 2-D shear wave elastography (SWE). Two normal (4 ± 1 kPa) and cirrhotic (16 ± 2 kPa) liver-mimicking phantoms with spherical inclusions (23 ± 3 kPa) were used. Inclusions of three sizes (20, 15 and 10 mm in diameter) were arranged in a row at depths of 3, 5 and 7 cm. Two observers acquired quantitative stiffness values and a qualitative five-grade morphologic score at each inclusion using SWE. The coefficients of variation (CVs) of stiffness were calculated to assess measurement reliability. The generalized estimating equation was used to identify whether stiffness, CV and morphologic score were independent of background stiffness, depth and size of inclusions and observer. In the quantitative assessment, stiffness of the inclusion and CV were dependent on the type of phantom and depth of inclusion (p < 0.001). There were no significant differences in stiffness and CV according to the observer. Morphologic score differed significantly only in the size of the inclusion (p < 0.001). When the depth of the inclusion was 7 cm, the stiffness was the highest, and the 10 mm-sized inclusions had lower morphologic scores than the other inclusions (all p values < 0.001). In conclusion, 2-D SWE assessment of focal lesions could be affected by background stiffness and depth of focal lesions, and may be limited in evaluating focal hepatic lesions.

Computer-Aided Diagnosis of Solid Breast Lesions With Ultrasound: Factors Associated With False-negative and False-positive Results

OBJECTIVES

To investigate factors that may lead to false-positive or false-negative results in a computer-aided diagnostic system (S-Detect; Samsung Medison Co, Ltd, Seoul, Korea) for ultrasound (US) examinations of solid breast lesions.

METHODS

This prospective study was approved by the Institutional Review Board of Sun Yat-sen Memorial Hospital. All patients signed and provided written informed consent before biopsy or surgery. From September 2017 to May 2018, 269 consecutive women with 338 solid breast lesions were included. All lesions were examined with US and S-Detect before biopsy or surgical excision. The final US assessments made by radiologists and S-Detect were matched to the pathologic results. Patient and lesion factors in the "true" and "false" S-Detect groups were compared, and multivariate logistic regression analyses were used to identify the factors associated with false S-Detect results.

RESULTS

The mean age of the patients ± SD was 42.6 ± 12.9 years (range, 18-77 years). Of the 338 lesions, 209 (61.8%) were benign, and 129 (38.2%) were malignant. Larger lesions, the presence of lesion calcifications detected by B-mode US, and grades of 2 and 3 according to Adler et al (Ultrasound Med Biol 1990; 16:553-559) were significantly associated with false-positive S-Detect results (odds ratio [OR], 1.071; P = .006; OR, 5.851; P = .001; OR, 1.726; P = .009, respectively). Smaller lesions and the absence of calcifications detected by B-mode US in malignant solid breast lesions were significantly associated with false-negative S-Detect results (OR, 1.141; P = .015; OR, 7.434; P = .016).

CONCLUSIONS

Larger benign lesions, the presence of lesion calcifications, and high degrees of vascularity are likely to show false-positive S-Detect results. Smaller malignant lesions and the absence of calcifications are likely to show false-negative S-Detect results.

Assessment of carotid plaque hardness in patients with fatty liver by shear wave elastography: Correlation with blood lipid levels

BACKGROUND

Ultrasound plays an important role in carotid plaque screening, density structure determination, and stability evaluation. Shear wave elastography (SWE), as a new method of ultrasonic elastography, can quantitatively evaluate the elastic hardness of biological tissues by analyzing the propagation velocity of shear wave. Therefore, quantitative analysis of hardness characteristics of different types of carotid plaques by SWE can provide a valuable reference for clinical evaluation of plaque stability.

AIM

To determine the hardness of different types of carotid plaques in patients with fatty liver by SWE, and to explore the correlation between the hardness and blood lipid levels.

Methods

Clinical data of 130 fatty liver patients with single carotid plaque were retrospectively analyzed. According to the echo of plaque under conventional ultrasound, the patients were divided into three groups: soft plaque group (40 cases), mixed plaque group (52 cases), and hard plaque group (38 cases). All plaques were examined by SWE. The mean Young's modulus (mean YM) of each plaque was measured and its correlation with low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) levels was analyzed.

Results

The mean YM and HDL-C levels in the hard plaque group were significantly higher than those in the mixed plaque group and soft plaque group (P < 0.05). The mean YM and HDL-C levels in the mixed plaque group were significantly higher than those in the soft plaque group (P < 0.05). The LDL-C level in the hard plaque group was significantly lower than that in the mixed plaque group and soft plaque group (P < 0.05). The LDL-C level in the mixed plaque group was significantly lower than that in the soft plaque group (P < 0.05). The mean YM of carotid plaque was negatively correlated with LDL-C (r = -0.71, P < 0.05), and positively correlated with HDL-C (r = 0.75, P < 0.05).

Conclusion

SWE can quantitatively evaluate the hardness of different types of carotid plaques, and the mean YM is correlated with blood lipids levels. SWE can provide elastic hardness information for clinical evaluation of plaque stability.

Can strain elastography improve the characterization of breast lesions identified during second-look MRI-directed sonographic examination?

PURPOSE

To evaluate strain elastography as a complementary tool for characterization of lesions identified during second-look MRI-directed sonographic examination.

METHODS

We reviewed 83 breast lesions evaluated with MRI, secondlook ultrasound (US) and strain elastography in 75 consecutive patients (median age, 56 years). US-guided biopsies were performed in all cases.

RESULTS

After histopathological examination, 44 lesions were benign, 38 were malignant and 1 was high-risk. At MRI, the mean size of the lesions was 12 mm. Forty lesions (48.2%) appeared as masses, 30 (36.1%) as "non-masses" and 13 (15.7%) as "foci." At second-look US examination, 56 (67.5%) appeared as masses (mean size, 7 mm) and 27 (32.5%) as non-masses (mean size, 14 mm). At strain elastography, among the 39 malignant/high risk lesions, 5 (12.8%) had a score of 4 or 5, whereas 16 (41%) had a score of 1 and 2 (false negative). Among the 44 benign lesions, 36 (82%) had a score of 1 or 2, whereas none had a score of 5. Sensitivity and specificity of strain elastography in the diagnosis of breast cancer were 58% and 81%, respectively.

CONCLUSION

The addition of strain elastography offers no benefit in the characterization of lesions identified on second-look US after breast MRI.(E1, 3).

Breast sonoelastography: Now and in the future

PURPOSE

The purpose of this study was to identify practice trends and opinions concerning breast sonoelastography in two different health care systems, one in Europe (France) and the other in North America (Province of Québec/Canada).

MATERIALS AND METHODS

We distributed an 11-item online survey among French and Canadian breast radiologists. The survey comprised of four sections: (i) personal practice characteristics, (ii) breast sonoelastography usage in daily practice and evaluation of its usefulness, (iii) limitations and roles of sonoelastogrpahy in their clinical practice, and (iv) types of elastographic technique and interpretation.

RESULTS

We found that sonoelastography of the breast appears unpopular among Canadian radiologists, and poorly credible among French radiologists, who perceive it as an unreliable technique. To date, its real impact in clinical practice remains uncertain.

CONCLUSION

Continued learning and awareness of the indications, advantages and limitations of breast sonoelastography may motivate breast radiologists to adopt its use.

Virtual touch tissue imaging and quantification (VTIQ) in the evaluation of breast lesions: The associated factors leading to misdiagnosis

PURPOSE

To investigate the factors that could cause a misdiagnosis in virtual touch tissue imaging and quantification (VTIQ) when differentiating benign and malignant breast lesions, and to analyze the imaging characteristics of those lesions with incorrect findings.

METHODS

The conventional ultrasound (CUS) features and the VTIQ parameters of 153 benign lesions and 99 malignant lesions were retrospectively analyzed and compared with histopathological and/or core-needle biopsy (CNB)-proven results. Independent variables that led to inaccurate VTIQ results were selected by binary logistic regression analysis.

RESULTS

The maximum shear wave speed (SWS-max), the mean SWS (SWS-mean), the minimum SWS (SWS-min), the lesion-to-fat SWS ratio (SWS-L/F), and the lesion-to-gland SWS ratio (SWS-L/G) in malignant lesions were significantly higher than those in benign lesions (all P < 0.001). The false-positive rate (FPR) of benign lesions and the false-negative rate (FNR) of malignant lesions were 9.8% and 19.2%, respectively, using an SWS-max cut-off value of 4.46 m/s. Diameter, depth, and posterior acoustic features were independent variables related to false-positive VTIQ findings (P: 0.049, 0.010 and 0.032, respectively). The invasive status and the histologic grade of infiltrating carcinoma were significantly associated with false-negative VTIQ findings (P: 0.026 and 0.015).

CONCLUSION

Diameter, depth, posterior acoustic features, invasive status, and histologic grade have a significant influence on the accuracy of VTIQ results, and these characteristics of breast lesions should be taken into account when interpreting the results of VTIQ examinations.

Factors Affecting the Quality of Breast Quasistatic Ultrasound Elastograms

OBJECTIVES

To explore factors affecting the quality of quasistatic ultrasound elastograms of the breast and to evaluate their accuracy in distinguishing benign and malignant breast lesions.

METHODS

A total of 663 patients with 702 breast lesions were recruited. All patients received both conventional ultrasonography and quasistatic elastography. Patients' breast lesions were divided into A and B groups according to satisfactory and unsatisfactory elastographic examinations. Group A included 590 satisfactory elastograms, whereas Group B included 112 unsatisfactory elastograms. Various factors-maximum depth of the lesion, maximum transverse diameter of the lesion, thickness of the adipose layer, thickness of the glandular layer, thickness of the breast, distance between the nipple and lesion, age, body mass index, and menopausal status-were analyzed and compared between the groups to gauge their effects on the quality of the elastograms.

RESULTS

Significantly deeper lesions, higher maximum transverse lesion diameters, thicker adipose layers, thicker glandular layers, and thicker breasts were identified in group B patients compared to group A patients (P < .05). Multivariate logistic regression analyses showed that the maximum depth of the lesion, thickness of the adipose layer, and thickness of the breast were independent factors in the quality of elastograms. The area under the curve for the maximum depth of the lesion was 0.986 with the optimal cutoff threshold of 2.5 cm.

CONCLUSIONS

Quasistatic elastography can be a supplementary approach to conventional ultrasonography in helping improve the diagnostic accuracy of breast lesions. The depth and size of breast lesions are correlated with the quality of elastograms.

Differentiating the acute phase of gout from the intercritical phase with ultrasound and quantitative shear wave elastography

OBJECTIVES

To evaluate the value of ultrasound (US) in differentiating the acute phase of gout from the intercritical phase, particularly using shear wave elastography (SWE).

METHODS

57 gout patients were prospectively enrolled and divided into acute phase and intercritical phase groups. The patients underwent US and SWE examinations for the first metatarsophalangeal joints with the same protocol. Maximum synovial thickness was measured. US features were reviewed by two radiologists independently. The maximum (E_max) and mean (E_mean) elastic moduli of synovium were calculated. Diagnostic performances of US, SWE and combined US and SWE were evaluated.

RESULTS

US findings demonstrated that the colour Doppler flow signal grade in the acute phase was higher than that in the intercritical phase (p = 0.001), whereas no differences were found for B-mode US features between the two groups (all p > 0.05). For SWE, E_max and E_mean were significantly higher in the intercritical phase than in the acute phase (both p < 0.001). The areas under the receiver operating characteristic curve (AUROCs) were 0.494-0.553 for B-mode US, 0.735 for colour Doppler US (CDUS), 0.887 for E_max and 0.882 for E_mean. The combination of CDUS and SWE increased the AUROC, sensitivity and accuracy significantly in comparison with CDUS alone (all p < 0.001). However, the combined set did not show stronger diagnostic performance in comparison with SWE alone.

CONCLUSION

SWE increases the diagnostic performance in differentiating the acute phase of gout from the intercritical phase in comparison with conventional US.

KEY POINTS

• Colour Doppler flow signal grade is higher in acute phase of gout than in intercritical phase. • SWE demonstrates that synovium stiffness is higher in intercritical phase of gout than in acute phase. • SWE increases diagnostic performance in differentiating acute phase of gout from intercritical phase in comparison with conventional US.

Principles of ultrasound elastography

Tissue stiffness has long been known to be a biomarker of tissue pathology. Ultrasound elastography measures tissue mechanical properties by monitoring the response of tissue to acoustic energy. Different elastographic techniques have been applied to many different tissues and diseases. Depending on the pathology, patient-based factors, and ultrasound operator-based factors, these techniques vary in accuracy and reliability. In this review, we discuss the physical principles of ultrasound elastography, discuss differences between different ultrasound elastographic techniques, and review the advantages and disadvantages of these techniques in clinical practice.

Shear-wave elastography in breast ultrasonography: the state of the art

Shear-wave elastography (SWE) is a recently developed ultrasound technique that can visualize and measure tissue elasticity. In breast ultrasonography, SWE has been shown to be useful for differentiating benign breast lesions from malignant breast lesions, and it has been suggested that SWE enhances the diagnostic performance of ultrasonography, potentially improving the specificity of conventional ultrasonography using the Breast Imaging Reporting and Data System criteria. More recently, not only has SWE been proven useful for the diagnosis of breast cancer, but has also been shown to provide valuable information that can be used as a preoperative predictor of the prognosis or response to chemotherapy.