Multiparametric ultrasound evaluation with CEUS and shear wave elastography for carotid plaque risk stratification

PURPOSE

To assess the diagnostic effectiveness of Multiparametric ultrasound (MPUS), which includes color Doppler ultrasound (CDUS), CEUS and Shear wave elastography (SWE), for evaluating carotid plaque as compared with CT-angiography (CTA) and histology.

MATERIALS AND METHODS

Forty-three consecutive patients scheduled to undergo carotid endarterectomy underwent MPUS. Then, after periods ranging from 2 days to 2 weeks, all underwent CTA. Each plaque was classified by means of dedicated scores for CEUS and SWE as compared with CTA features. At surgery, each plaque was removed in a single fragment to facilitate histological analysis, which evaluated 4 features: extension of the lipid core, thickness of the fibrous cap, inflammatory infiltrate (CD68 + and CD3 + markers) and the presence of intraplaque microvessels. For the CEUS, SWE and CTA, the following values for identifying plaque vulnerability were evaluated: sensitivity, specificity, accuracy, negative predictive value (NPV), positive predictive value (PPV) and Area under the curve (AUC). Cohen's kappa was used to evaluate the concordance between measurements in the different imaging methods. A p < 0.05 was considered statistically significant.

RESULTS

At histology, 31 out of 43 plaques were identified as vulnerable because of the presence of at least one of the following criteria: fibrous cap < 200 μm, lipid core, intraplaque hemorrhage, inflammatory infiltrate or intraplaque neovascularization. CTA showed a sensitivity of 87.1%, a specificity of 100%, a PPV of 100%, an NPV of 75% and an AUC of 93.5%. SWE showed a sensitivity of 87.1%, a specificity of 66.7%, a PPV of 87.1%, an NPV of 66.7% and an AUC of 76.9%. CEUS showed a sensitivity of 87.1%, a specificity of 58.3%, a PPV of 84.4%, an NPV of 63.6% and an AUC of 72.7%.

CONCLUSIONS

Multiparametric ultrasound is an effective modality to obtain comprehensive information on carotid plaques. Further studies are needed to determine whether it can be considered a diagnostic standard.

What is the role of contrast-enhanced ultrasound in the evaluation of the endoleak of aortic endoprostheses? A comparison between CEUS and CT on a widespread scale

OBJECTIVE

To evaluate the accuracy of contrast-enhanced ultrasound (CEUS) in comparison to CT angiography (CTA) to identify and classify endoleaks following abdominal aortic aneurism repair with endoprosthesis.

MATERIALS AND METHODS

A retrospective analysis of 181 patients treated with EVAR, from September 2009 to September 2014, was performed. Patients were evaluated with CEUS, CTA and angiography in the cases requiring treatment. Sac diameter, sac integrity, identification and classification of endoleaks were taken into consideration. Sensitivity, specificity, accuracy and negative predictive values were considered for each modality of endoleak identification.

RESULTS

Forty-two endoleaks (23.2%; type II: 39 cases, type III: 3 cases) were documented. Sensitivity and specificity of CEUS and CT were, respectively, 97.6 and 90.5, 100 and 100%. In two cases, CEUS was able to better classify endoleaks compared to CT.

CONCLUSIONS

CEUS accuracy to identify endoleaks following EVAR is similar to CT. CEUS should be considered as an effective modality for the long-term surveillance of EVAR because of its capability to correctly classify endoleaks with no ionizing radiation exposure.

Parotid Gland Lesions: Multiparametric Ultrasound and MRI Features

High-resolution ultrasound (US), as a readily available, cost-effective and harmless imaging technique, is appropriately the initial imaging modality for salivary gland lesions. Benign tumors are reported to present with regular and well-defined margins, a homogeneous hypoechoic structure and demarcated vessel distribution, whereas malignant lesions are irregular, heterogeneous and diffusely perfused. Ultrasound and color Doppler features of benign and malignant salivary gland lesions overlap, and many benign tumors, particularly pleomorphic adenomas, may appear irregularly shaped, with a heterogeneous echo-structure indistinguishable from a malignant lesion. Often skilled US operators are not always able to differentiate benign from malignant lesions. The introduction of US contrast agents has allowed further perspectives in the possible improvement of lesion characterization, and the emergence of US elastography, an innovative tool for assessing lesion stiffness/elasticity characteristics, has been advocated for differentiating salivary gland lesions. When lesions are atypical on US, contrast-enhanced magnetic resonance (MR) imaging is usually the definitive imaging modality. We present a current review of benign and malignant parotid gland tumors with emphasis on the role of multiparametric US and MR imaging.

CEUS in the study of bladder, method, administration and evaluation, a technical note

PURPOSE

Contrast-enhanced ultrasound (CEUS) is the application of ultrasound contrast agents (UCAs) to traditional medical sonography. The development of UCAs allowed to overcome some of the limitations of conventional B-mode and Doppler ultrasound techniques and enabled the display of the parenchymal microvasculature. Purpose of this paper is to delineate the elements of a solid and science-based technique in the execution of urinary bladder CEUS.

METHODS

We describe the technical execution of urinary bladder CEUS and the use of perfusion softwares to perform contrast enhancement quantitative analysis with generation of time-intensity curves from regions of interest.

RESULTS

During CEUS, normal bladder wall shows a wash-in time of 13 s, a time to peak (TTP) >40 s, a signal intensity (SI) <45 % and a wash-out time >80 s; Low-grade urothelial cell carcinoma (UCC) shows a wash-in time of 13 s, a time to peak TTP >28 s, a SI <45 % and a wash-out time of 40 s; High-grade UCC shows a wash-in time of 13 s, a TTP >28 s, a SI >50 % and a wash-out time of 58 s.

CONCLUSIONS

CEUS is a useful tool for an accurate characterization of bladder UCC although it has some drawbacks. To avoid misunderstandings, a widely accepted classification and a standardized terminology about the most significant parameters of this application should be adopted in the immediate future.

Update on ultrasound elastography: miscellanea. Prostate, testicle, musculo-skeletal

Nowadays ultrasound elastosonography is an established technique, although with limited clinical application, used to assess tissue stiffness, which is a parameter that in most cases is associated with malignancy. However, although a consistent number of articles have been published about several applications of elastosonography, its use in certain human body districts is still not well defined. In this paper we write on the use of elastosonography in prostate, testicle and musculo-skeletal apparatus. We report and compare the work of several authors, different type of elastosonography (shear wave, strain elastography, etc.) and instrumental data obtained in the study of both benign and malignant lesions.

Contrast-enhanced ultrasonography in the diagnosis of upper urinary tract urothelial cell carcinoma: a preliminary study

PURPOSE

The main objective was to assess the effectiveness of contrast-enhanced ultrasonography (CEUS) in the diagnosis of upper urinary tract malignancies by comparing with multidetector computed tomographic urography (MDCTU) and magnetic resonance urography (MRU). Secondary objectives were to compare the tumor size measured with CEUS, MDCTU and MRU and to assess the usefulness of CEUS in distinguishing high-grade tumors from low-grade ones.

MATERIALS AND METHODS

In connection with this prospective study carried out from January 2009 to September 2011, 18 patients underwent MDCTU or MRU, grayscale ultrasonography (US), color Doppler ultrasonography and CEUS followed by surgery and histological examination of the specimen. Quantitative analysis was performed using perfusion software. Time intensity curves were extracted and the following parameters were considered: wash-in time, time-to-peak, maximum signal intensity and wash-out time.

RESULTS

Grayscale US identified 15/18 lesions; color Doppler showed no flow signal in 8 lesions, low color signal in 9 lesions and an intense color signal in 1 lesion; CEUS identified 17/18 lesions with the undetected lesion being the smallest one (1.2 cm) located in the upper pelvicalyceal system. Semi-quantitative analysis produced different data for high-grade and low-grade urothelial cell carcinoma (UCC). All detected upper urinary tract masses were UCCs. MRU, MDCTU and grayscale US overestimated the tumor size, while CEUS was the most accurate.

CONCLUSION

CEUS is useful for evaluating upper urinary tract masses as this method permits differentiation between high-grade and low-grade tumors as well as distinction of the tumor from the adjacent structures and accurate mass measurements.

Contrast-enhanced ultrasound examination of the breast: a literature review

Angiogenesis is the basis for neoplastic growth in human tissues. Nevertheless, neovascularization may be present both in benign and malignant lesions. Although microvascular density assessment is a useful tool for the study of neoplastic vascularization, it cannot be used on a large scale because of the invasiveness of the method. When contrast-enhanced ultrasonography (CEUS) was introduced in clinical practice, the initial results in the field of breast lesions were disappointing because differentiation between benign and malignant masses was not possible. Magnetic resonance imaging (MRI) assessment of the microvascular features was therefore immediately accepted because of the higher diagnostic accuracy. However, in the last decade the sensitivity and specificity of CEUS have greatly improved due to the development of more sophisticated ultrasound (US) equipment, the introduction of second-generation contrast agents and the development of dedicated software able to perform quantitative analysis. This literature review compares the main results reported in the literature regarding the use of CEUS for the characterization of neoplastic lesions of the breast. All the authors agreed that malignant lesions show early wash-in with more intense enhancement and fast wash-out in comparison with benign masses. However, there is still no observer agreement regarding vascularization patterns, and different classifications are proposed. The conclusion of this literature review is therefore that the clinical role of CEUS in the diagnostic process and in follow-up is still to be clearly defined.

CEUS in the differentiation between low and high-grade bladder carcinoma

INTRODUCTION

Bladder cancer ranks 4th overall in the number of newly diagnosed cancers and 10th in causes of cancer deaths. More than 90% of all cases of bladder cancer are transitional cell carcinoma (TCC). The goal of this study is to confirm the usefulness of low mechanical index contrast-enhanced ultrasonography (CEUS), also in association with time-intensity curves, in the differentiation between high- and low-grade bladder malignant lesions.

MATERIALS AND METHODS

From February 2006 to February 2012 we recruited 144 patients. All patients underwent grayscale ultrasonography (US), color-Doppler ultrasonography (CDUS) and contrast-enhanced ultrasonography (CEUS). Subsequently all patients underwent cystoscopy and TURB.

RESULTS

HISTOLOGICAL DIAGNOSES WERE: 88 high-grade carcinomas (61.1%), and 56 low-grade carcinomas (38.9%). Sensitivity and specificity of CDUS were 87.5% (126/144) and 60%, respectively. Sensitivity and specificity of CEUS were 90.9% and 85.7%, respectively. Sensitivity and specificity of TIC were 91.6% (132/144) and 85.7%, respectively.

DISCUSSION AND CONCLUSIONS

CEUS is a reliable noninvasive method for differentiating low- and high-grade bladder carcinomas since it provides typical enhancement patterns as well as specific contrast-sonographic perfusion curves.

Varicocele: Ultrasonographic assessment in daily clinical practice

INTRODUCTION

Varicoceles are abnormal dilatations of the pampiniform venous plexus. They are classified as primary or secondary, depending on their cause, and staged clinically on the basis of their extension and on the presence or the absence of spontaneous or induced reversal of blood flow.

MATERIALS AND METHODS

We examined 95 patients (age range: 3-77 years) using Color Doppler ultrasound with settings optimized for the study of slow flow. All patients found to have varicoceles underwent ultrasonographic assessment of the kidneys and retroperitoneum. Findings were classified with a simplified version of the Sarteschi system.

RESULTS

41 (43.1%) of the patients were found to have varicoceles, which were classified as grade 1 in 11 cases, grade 2 in 13, grade 3 in 10, and grade 4 in 7 according to the simplified Sarteschi classification.

DISCUSSION

Our results are with those reported in the literature. They confirm that varicoceles are a frequent finding and ultrasonography is currently the best imaging technique for its diagnosis and also for the post-surgery follow-up.

Role of low-mechanical index CEUS in the differentiation between low and high grade bladder carcinoma: a pilot study

PURPOSE

To assess the efficacy of low-mechanical index contrast-enhanced ultrasonography (CEUS) in the differentiation of a series of histologically proven bladder lesions identified via conventional cystoscopy and biopsied.

MATERIALS AND METHODS

36 patients (mean age: 62 years; range 45 - 72 years) with bladder lesions previously detected by color power Doppler ultrasonography (CDUS) were prospectively examined with low-mechanical index contrast-enhanced US after bolus administration of 2.4 ml of Sonovue (Bracco, Milan, Italy). All lesions were evaluated in real-time continuous scanning for 2 minutes and the videos were registered. Two ultrasound (US) experts evaluated the videos by consensus and assigned a score to the enhancement pattern. Subsequently, a specific sonographic quantification software (Qontrast, Bracco, Milan, Italy) based on pixel by pixel signal intensity over time was used to obtain contrast-enhanced sonographic perfusion maps for each lesion. Time-intensity curves (TICs) of each lesion were then extracted from the region of interest positioned within the lesion and in the closest bladder wall. The sensitivity and specificity of CDUS and CEUS were compared using McNemar's test. All patients subsequently underwent conventional cystoscopy with biopsy or transurethral resection.

RESULTS

22 high-grade and 14 low-grade transitional cell carcinomas (TCCs) were histologically diagnosed (mean diameter 2.1 cm; range: 1 - 4.5 cm). The sensitivity and specificity of CDUS were 86.4% (19 / 22; 95% CI = 66.7 - 95.3%) and 42.9% (6 / 14; 95% CI = 21.4 - 67.4%), respectively. The sensitivity and specificity of CEUS were 90.9% (20 / 22; 95% CI = 72.2 - 97.5%) and 85.7% (12 / 14; 95% CI = 60.1 - 95.9%), respectively. The sensitivity and specificity of CEUS using TICs were 95.4% (21 / 22; 95% CI = 78.2 - 99.2%) and 85.7% (12 / 14; 95% CI = 60.1 - 95.9%), respectively. There was no significant difference between the sensitivity of CDUS versus CEUS, CDUS versus TIC, and CEUS versus TIC (p > 0.05; McNemar's test). The specificity of CEUS and TIC was significantly higher than that of CDUS (p < 0.05; McNemar test).

CONCLUSION

CEUS is a reliable noninvasive method for differentiating low- and high-grade bladder carcinomas since it provides typical enhancement patterns as well as specific contrast-sonographic perfusion curves. However, further studies involving larger patient populations is mandatory to confirm these promising results.