Le-Hang Guo

Virtual Touch Tissue Quantification of Acoustic Radiation Force Impulse: A New Ultrasound Elastic Imaging in the Diagnosis of Thyroid Nodules

Objective Virtual touch tissue quantification (VTQ) of acoustic radiation force impulse (ARFI) is a new quantitative technique to measure tissue stiffness. The study was aimed to assess the usefulness of VTQ in the diagnosis of thyroid nodules. Methods 173 pathologically proven thyroid nodules in 142 patients were included and all were examined by conventional ultrasound (US), conventional elasticity imaging (EI) and VTQ of ARFI. The tissue stiffness for VTQ was expressed as shear wave velocity (SWV) (m/s). Receiver-operating characteristic curve (ROC) analyses were performed to assess the diagnostic performance. Intra- and inter-observer reproducibility of VTQ measurement was assessed. Results The SWVs of benign and malignant thyroid nodules were 2.34±1.17 m/s (range: 0.61–9.00 m/s) and 4.82±2.53 m/s (range: 2.32–9.00 m/s) respectively (P<0.001). The mean SWV ratios between each nodule and the adjacent thyroid tissue were 1.19±0.67 (range: 0.31–6.87) for benign and 2.50±1.54 (range: 0.85–6.69) for malignant nodules (P<0.001). ROC analyses indicated that the area under the curve was 0.861 (95% CI : 0.804, 0.918) (P<0.001) for SWV and 0.831(95% CI : 0.761, 0.900)(P<0.001) for the SWV ratio. The cutoff points for the differential diagnosis were 2.87 m/s for SWV and 1.59 for SWV ratio. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for EI were 65.9%, 66.7%, 66.5%, 40.3%, and 85.1%, respectively, and were 63.6%–75%, 82.2%–88.4%, 80.3%–82.1%, 58.9%–65.1%, and 87.7%–90.5%, respectively, for VTQ. The diagnostic value of VTQ is the highest for nodules >20 mm and lowest for those ≤10 mm. The correlation coefficients were 0.904 for intraobserver measurement and 0.864 for interobserver measurement. Conclusions VTQ of ARFI provides quantitative and reproducible information about the tissue stiffness, which is useful for the differentiation between benign and malignant thyroid nodules. The diagnostic performance of VTQ is higher than that of conventional EI.

Conventional US, US Elasticity Imaging, and Acoustic Radiation Force Impulse Imaging for Prediction of Malignancy in Thyroid Nodules

PURPOSE To evaluate conventional ultrasonography (US), US elasticity imaging (EI), and acoustic radiation force impulse (ARFI) imaging in thyroid nodule malignancy prediction. MATERIALS AND METHODS This prospective study was institutional review board approved; informed consent was obtained. Study included 375 patients (mean age, 51 years; range, 18-75 years) with 441 pathologically proven thyroid nodules. In 281 women (mean age, 50 years; range, 18-75 years) and 94 men (mean age, 53 years; range, 18-74 years), conventional US, EI, Virtual Touch tissue imaging (VTi; Siemens, Mountain View, Calif), and Virtual Touch tissue quantification (VTq; Siemens) of ARFI imaging were performed for each nodule. Multivariate logistic regression analysis was performed to assess 17 independent variables for malignancy prediction. Diagnostic performance was evaluated with receiver operating characteristic (ROC) curve analysis. RESULTS There were 325 benign and 116 malignant nodules. Marked hypoechogenicity (odds ratio [OR]: 83.88; 95% confidence interval [CI]: 17.81, 394.99) was the strongest independent predictor for thyroid malignancy, followed by shape taller than wide (OR: 8.69; 95% CI: 2.87, 26.31), VTi (OR: 6.54; 95% CI: 3.61, 11.88), moderate hypoechogenicity (OR: 3.98; 95% CI: 1.13, 14.05), poorly defined margin (OR: 3.27; 95% CI: 1.22, 8.77), female sex (OR: 2.55; 95% CI: 1.33, 4.91), coarse background of surrounding thyroid tissue (OR: 2.01; 95% CI: 1.12, 3.62), and VTq (OR: 1.78; 95% CI: 1.28, 2.47) (all P < .05). EI was not significantly associated with thyroid malignancy (P = .855). Area under the ROC curve (Az) for VTq and VTi was higher than that with other significant independent variables. Az, sensitivity, and specificity were 0.91 (95% CI: 0.87, 0.94) and 0.86 (95% CI: 0.82, 0.90), 80% and 71.6%, and 93.8% and 83.4%, respectively, for VTi and VTq. VTq of at least 2.87 m/sec and VTi of at least grade IV were the best cutoff values for malignant thyroid nodules. CONCLUSION ARFI imaging is promising for malignant thyroid nodule prediction, with higher diagnostic performance than conventional US or EI. ARFI can be used to supplement conventional US to diagnose thyroid nodules in patients referred for surgery.

Acoustic Radiation Force Impulse Imaging for Noninvasive Evaluation of Renal Parenchyma Elasticity: Preliminary Findings

Objective To evaluate the diagnostic value of acoustic radiation force impulse (ARFI) to test the elasticity of renal parenchyma by measuring the shear wave velocity (SWV) which might be used to detect chronic kidney disease (CKD). Methods 327 healthy volunteers and 64 CKD patients were enrolled in the study. The potential influencing factors and measurement reproducibility were evaluated in the healthy volunteers. Correlations between SWV and laboratory tests were analyzed in CKD patients.?Receiver-operating characteristic curve (ROC) analyses were performed to assess the diagnostic performance of ARFI. Results The SWV of healthy volunteers correlated significantly to age (r = −0.22, P<0.001, n = 327) and differed significantly between men and women (2.06±0.48 m/s vs. 2.2±0.52 m/s, P = 0.018, n = 327). However, it did not correlate significantly to height, weight, body mass index, waistline, kidney dimension and the depth for SWV measurement (n = 30). Inter- and intraobserver agreement expressed as intraclass coefficient correlation were 0.64 (95% CI: 0.13 to 0.82, P = 0.011) and 0.6 (95% CI: 0.31 to 0.81, P = 0.001) (n = 40). The mean SWV in healthy volunteers was 2.15±0.51 m/s, while was 1.81±0.43 m/s, 1.79±0.29 m/s, 1.81±0.44 m/s, 1.64±0.55 m/s, and 1.36±0.17 m/s for stage 1, 2, 3, 4 and 5 in CKD patients respectively. The SWV was significantly higher for healthy volunteers compared with each stage in CKD patients. ARFI could not predict the different stages of CKD except stage 5. In CKD patients, SWV correlated to e-GFR (r = 0.3, P = 0.018), to urea nitrogen (r =  −0.3, P = 0.016), and to creatinine (r =  −0.41, P = 0.001). ROC analyses indicated that the area under the ROC curve was 0.752 (95% CI: 0.704 to 0.797) (P<0.001). The cut-off value for predicting CKD was 1.88 m/s (sensitivity 71.87% and specificity 69.69%). Conclusion ARFI may be a potentially useful tool in detecting CKD.

Virtual touch tissue imaging on acoustic radiation force impulse elastography: a new technique for differential diagnosis between benign and malignant thyroid nodules.

Acoustic radiation force impulse elastography is a newly developed ultrasound elasticity imaging technique that included both Virtual Touch tissue quantification and Virtual Touch tissue imaging (VTI; Siemens Medical Solutions, Mountain View, CA). This study aimed to evaluate the usefulness of VTI in differentiating malignant from benign thyroid nodules.

Solid hypo-echoic thyroid nodules on ultrasound: the diagnostic value of acoustic radiation force impulse elastography.

The aim of the study described here was to evaluate the diagnostic performance of acoustic radiation force impulse (ARFI) elastography in the differential diagnosis between benign and malignant solid hypo-echoic thyroid nodules (SHTNs) on ultrasound. In this retrospective study, 183 histologically proven SHTNs in 159 patients were enrolled. Conventional US, as well as Virtual Touch tissue imaging (VTI) and Virtual Touch tissue quantification (VTQ) of ARFI elastography, was performed on each nodule. The VTI features of SHTNs were divided into six grades, where higher grades represent harder tissue. VTQ was expressed as shear wave velocity, where higher shear wave velocity values indicate stiffer tissue. The sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Youden index for ultrasound and ARFI were assessed. The 183 pathologically proven SHTNs included 117 benign and 66 malignant lesions. Nodules classified as VTI grades IV to VI were more frequently malignant (49/66, 74.2%) than benign (10/117, 8.5%) (p < 0.001). The mean shear wave velocity of VTQ for malignant SHTNs (mean ± standard deviation, 4.65 ± 2.68 m/s; range, 1.36-9 m/s) was significantly higher than that for benign SHTNs (2.34 ± 0.85 m/s, 0-5.7 m/s) (p < 0.001). The sensitivity, specificity, accuracy, positive predictive value, negative predictive value and Youden index were 27.3%-84.8%, 13.7%-89.7%, 39.3%-69.4%, 35.7%-60%, 61.5%-78.5%, and -0.015 to 0.37 for ultrasound; 68.2%, 76.9%, 73.8%, 62.5%, 81.1% and 0.451 for VTQ; and 74.2%, 91.5%, 85.2%, 83.1%, 86.3% and 0.657 for VTI, respectively. ARFI elastography performed at a superior level, compared with conventional ultrasound, in the differential diagnosis between malignant and benign SHTNs. The diagnostic performance of VTI is higher than that of VTQ.

Contrast-enhanced ultrasound of intrahepatic cholangiocarcinoma: correlation with pathological examination

OBJECTIVE To investigate the correlation between enhancement patterns of intrahepatic cholangiocarcinoma (ICC) on contrast-enhanced ultrasound (CEUS) and pathological findings. METHODS The CEUS enhancement patterns of 40 pathologically proven ICC lesions were retrospectively analysed. Pathologically, the degree of tumour cell and fibrosis distribution in the lesion was semi-quantitatively evaluated. RESULTS 4 enhancement patterns were observed in the arterial phase for 32 mass-forming ICCs: peripheral rim-like hyperenhancement (n=19); heterogeneous hyperenhancement (n=6); homogeneous hyperenhancement (n=3); and heterogeneous hypo-enhancement (n=4). Among the four enhancement patterns, the differences in tumour cell distribution were statistically significant (p<0.05). The hyperenhancing area on CEUS corresponded to more tumour cells for mass-forming ICCs. Heterogeneous hyperenhancement (n=2) and heterogeneous hypo-enhancement (n=2) were observed in the arterial phase for four periductal infiltrating ICCs. In this subtype, fibrosis was more commonly found in the lesions. Heterogeneous hyperenhancement (n=1) and homogeneous hyperenhancement (n=3) were observed in the arterial phase for four intraductal growing ICCs. This subtype tended to have abundant tumour cells. CONCLUSION The CEUS findings of ICC relate to the degree of carcinoma cell proliferation at pathological examination. Hyperenhancing areas in the tumour always indicated increased density of cancer cells.

Treatment efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation for benign thyroid nodules

OBJECTIVE To evaluate the therapeutic efficacy and safety of ultrasound-guided percutaneous bipolar radiofrequency ablation (BRFA) of benign thyroid nodules by comparison with a matched untreated control group. METHODS The therapeutic efficacy and safety in 35 patients who were subjected to a single session of ultrasound-guided percutaneous BRFA (Group A) for benign thyroid nodules were compared with those in 35 untreated patients (Group B) with benign nodules. The benign nature of all the nodules was confirmed by ultrasound-guided fine-needle aspiration biopsy (FNAB), and all the patients had normal thyroid functions. BRFA was performed with a bipolar electrode (CelonProSurge 150-T20) with an output power of 20 W. Nodule volume, thyroid function and clinical symptoms of all the patients were compared before treatment and during follow-up. RESULTS In Group A, the BRFA procedures were completed with a mean time of 10.02 ± 3.30 min (range, 5.47-16.03 min) and with a mean total energy deposition of 10.747 ± 3704 J (range, 5510-17.770 J). The procedures were tolerated well in all the patients without causing any major complications. At the 6-month follow-up, all of the nodule volume decreased significantly (from 8.81 ± 8.66 to 1.59 ± 1.55 ml, p < 0.001) in Group A, whereas the nodule volume increased from 6.90 ± 3.77 to 7.87 ± 3.95 ml in Group B (p < 0.001). All (100%) the 35 nodules in Group A had volume reduction ratios (VRRs) of >50%, among which 3 (8.57%) had VRRs >90%. In Group A, the clinical symptoms of the patients who had symptoms before BRFA disappeared, whereas in Group B, the patients had no resolution of clinical symptoms at the 6-month follow-up. CONCLUSION Ultrasound-guided percutaneous BRFA seems to be an effective and safe method for the treatment of benign thyroid nodules. It may gain a wide use in clinical practice. ADVANCES IN KNOWLEDGE Based on the comparable efficacy and clinical symptoms between the BRFA and untreated groups, the technique of BRFA can be used as an effective and safe method for the treatment of benign thyroid nodules.

Acoustic Radiation Force Impulse Imaging: A New Tool for the Diagnosis of Papillary Thyroid Microcarcinoma

Purpose. To evaluate the diagnostic performance of ARFI imaging in differentiating between benign and malignant thyroid nodules <1 cm. Materials and Methods. 173 pathologically proven thyroid nodules (77 benign, 96 malignant) in 157 patients were included in this study. Receiver-operating characteristic curve (ROC) analyses were performed to assess the diagnostic performance of conventional ultrasound (US) and ARFI imaging in papillary thyroid microcarcinoma (PTMC). The independent risk factors for predicting PTMC were evaluated. Results. The mean SWV value of benign and malignant thyroid nodules were 2.57 ± 0.79 m/s (range: 0.90–4.92 m/s) and 3.88 ± 2.24 m/s (range: 1.49–9.00 m/s) (P = 0.000). Az for VTI elastography score was higher than that for hypoechoic, absence of halo sign, and type III vascularity (P < 0.05). The optimal cut-offs for VTI elastography score and SWV were score 4 and 3.10 m/s. Gender, hypoechoic, taller than wide, VTI elastography score ≥ 4, and SWV > 3.10 m/s had been found to be independent risk factors for predicting PTMC. Conclusion. ARFI elastography can provide elasticity information of PTMC quantitatively (VTQ) and directly reflects the overall elastic properties (VTI). Gender, hypoechogenicity, taller than wide, VTI elastography score ≥ 4, and SWV > 3.10 m/s are independent risk factors for predicting PTMC. ARFI elastography seems to be a new tool for the diagnosis of PTMC.

Imaging features of intrahepatic biliary cystadenoma and cystadenocarcinoma on B-mode and contrast-enhanced ultrasound.

PURPOSE To investigate the imaging features of intrahepatic biliary cystadenoma and cystadenocarcinoma on B-mode and contrast-enhanced ultrasound. MATERIALS AND METHODS The B-mode and contrast-enhanced ultrasound features of 6 intrahepatic biliary cystadenomas and 7 intrahepatic biliary cystadenocarcinomas were retrospectively analyzed, and the differences between cystadenomas and cystadenocarcinomas were compared. RESULTS There were no significant differences between cystadenomas and cystadenocarcinomas in terms of patient gender, age, lesion location, size, and shape (all p > 0.05). On conventional ultrasound, biliary cystadenomas were more likely to be multilocular (6/6 for cystadenoma vs. 2/7 for cystadenocarcinoma) and cystadenocarcinomas more likely presented the features of a mural or septal nodule and a nodule diameter > 1.0 cm (0/6 for cystadenoma vs. 5/7 for cystadenocarcinoma). On contrast-enhanced ultrasound, hyper-enhancement (n = 4) or iso-enhancement (n = 2) was present in the cystic wall, septations or mural nodules of the cystadenomas during the arterial phase and the enhancement washed out to hypo-enhancement (n = 6) during the late phase. Cystadenocarcinomas also showed hyper-enhancement (n = 4) or iso-enhancement (n = 3) in the cystic wall, septations or mural nodules during the arterial phase and iso-enhancement (n = 1) or hypo-enhancement (n = 6) during the late phase. CONCLUSION Intrahepatic biliary cystadenomas are more typically multilocular cystic lesions. A mural or septal nodule and a nodule diameter greater than 1.0 cm on conventional ultrasound are suggestive of cystadenocarcinomas. Contrast-enhanced ultrasound is helpful for depicting the vascularity of the lesions but there was no significant difference between cystadenomas and cystadenocarcinomas.

Parametric imaging with contrast-enhanced ultrasound for differentiating hepatocellular carcinoma from metastatic liver cancer

AIM To evaluate the diagnostic performance of parametric imaging with contrast-enhanced ultrasound(CEUS) for differentiating hepatocellular carcinoma(HCC) from metastatic liver cancer(MLC). METHODS 30 HCCs (mean diameter, 3.6±1.3 cm; range, 2.1-5.0 cm) and 30 MLCs (mean diameter, 2.8±1.5 cm; range, 1.2-5.0 cm) pathologically diagnosed or confirmed by clinical criteria that underwent CEUS were randomly included. CEUS was carried out using a multifrequency transducer (2-4 MHz) and a bolus injection of 2.4 mL SonoVue. The CEUS clips of the targeted lesion were recorded continuously for 6 minutes. By analyzing CEUS clips, parametric image could be obtained using the SonoLiver® software automatically. Quantitative parameters were compared between HCC and MLC groups. Receiver operating characteristic (ROC) curve analysis was further performed on parameters with significant difference between two groups. RESULTS On parametric imaging, the maximum intensity, rise time, time to peak, mean transit time and washout time for HCC and MLC were 185.6±148.0 vs. 95.2±58.6 (P = 0.003), 25.7±6.3 s vs. 23.8±8.8 s (P = 0.341), 30.7±7.9 s vs. 27.8±10.5 s (P = 0.246), 90.2±45.7 s vs. 89.3±40.3 s (P = 0.805), 63.4±29.5 s vs. 37.2±33.8 s (P = 0.005), respectively. ROC analysis was further performed for washout time and it showed a cut-off point of 43.765 s for the differentiation between HCC and MLC, with the AUC value of 0.780 (95% CI: 0.646-0.914). The corresponding diagnostic specificity, sensitivity and accuracy were 72.0%, 84.6% and 78.4% respectively. CONCLUSIONS Parametric imaging of CEUS can display perfusion effects of HCC and MLC objectively and visually and washout time may serve as a useful parameter on the differential diagnosis between HCC and MLC.