Contrast-enhanced ultrasound: The evolving applications

Contrast-enhanced ultrasound (CEUS) is a major breakthrough for ultrasound imaging in recent years. By using a microbubble contrast agent and contrast-specific imaging software, CEUS is able to depict the micro- and macro-circulation of the targeted organ, which in turn leads to improved performance in diagnosis. Due to the special dual blood supply system in the liver, CEUS is particularly suitable for liver imaging. It is evident that CEUS facilitates improvement for characterization of focal liver lesions (FLLs), detection of liver malignancy, guidance for interventional procedures, and evaluation of treatment response after local therapies. CEUS has been demonstrated to be equal to contrast-enhanced computed tomography or magnetic resonance imaging for the characterization of FLLs. In addition, the applicability of CEUS has expanded to non-liver structures such as gallbladder, bile duct, pancreas, kidney, spleen, breast, thyroid, and prostate. The usefulness of CEUS in these applications is confirmed by extensive literature production. Novel applications include detecting bleeding sites and hematomas in patients with abdominal trauma, guiding percutaneous injection therapy and therefore achieving the goal of using interventional ultrasonography in managing splenic trauma, assessing the activity of Crohn's disease, and detecting suspected endoleaks after endovascular abdominal aneurysm repair. Contrast-enhanced intraoperative ultrasound (US) and intracavitary use of CEUS have been developed and clinically studied. The potential use of CEUS involves sentinel lymph node detection, drug or gene delivery, and molecular imaging. In conclusion, the advent of CEUS has greatly enhanced the usefulness of US and even changed the status of US in clinical practice. The application of CEUS in the clinic is continuously evolving and it is expected that its use will be expanded further in the future.     

Era of diagnostic and interventional ultrasound

It is an era of diagnostic and interventional ultrasound (US).Various new techniques such as three-dimensional US(3D US),interventional US,and contrastenhanced US(CEUS)have been introduced into clinical practice.Dr.Xu and his colleagues have taken advantage of these techniques and carried out a series of relevant studies.Their use of 3D US in the liver,gallbladder,liver tumor volumetry,guidance for ablation,and 3D CEUS has widened the application of 3D US in the clinic.They found that prognosis in patients with hepatocellular carcinoma(HCC)after thermal ablation with curative intent was determined by treatment response to ablation,pretreatment serum AFP,and liver function reserve.Tumor response to treatment was the most predictive factor for long-term survival.They compared the use of percutaneous microwave ablation and radiofrequency ablation for the treatment of HCC and found that both are effective methods in treating HCCs.The local tumor control,complications related to treatment, and long-term survival were equivalent for the two modalities.They first compared the enhancement patterns of HCC and intrahepatic cholangiocarcinoma(ICC)and proposed the diagnostic clues for ICC,liver angiomyolipoma(AML),gallbladder cancer,renal carcinoma,and renal AML,which have greatly enhanced the role ofCEUS in the clinic.They also evaluated the diagnostic performance of CEUS in characterizing complex cystic focal liver lesions and the agreement between two investigators with different experience levels;and found that CEUS is especially useful for the young investigator.They assessed the effect of anti-angiogenic gene therapy for HCC treated by microbubble-enhanced US exposure and concluded that gene therapy mediated by US exposure enhanced by a microbubble contrast agent may become a new treatment option for HCC.     

Contrast-enhanced ultrasonography in the follow-up of patients with hepatic metastases from breast carcinoma

PURPOSE: Oncological treatment planning relies on the evaluation of treatment response, which is defined by the change in size of measurable lesions. The purpose of this study was to evaluate the use of contrast-enhanced ultrasound (CEUS) to obtain a precise measurement of hepatic metastases in breast cancer patients with fatty-liver disease. MATERIALS AND METHODS: Twelve consecutive patients with 25 liver metastases from breast cancer and fatty liver disease, as defined by US criteria, were enrolled in this prospective study. All patients underwent conventional US, CEUS and multidetector computed tomography (MDCT), used as the gold standard for measuring the maximum diameter of lesions. Agreement between US, CEUS and MDCT measurements was analysed using Altman-Bland plots; 95% confidence limits were calculated for the difference among means. RESULTS: Mean diameter as measured by MDCT was 26.2 mm (range 11-83). US allowed measurement of 20/25 lesions. In 15 lesions, CEUS measurements were more accurate than those obtained by US. The difference among means was 1.1 mm with a 95% confidence interval (-9.2, 11.4) for US measurements and 0.6 mm with a 95% confidence interval (-2.0, 3.1) for CEUS. CONCLUSIONS: Our preliminary data show that CEUS can be used to obtain more accurate measurements than conventional US for the follow-up of patients with metastases in fatty liver.     

Application of contrast-enhanced ultrasound in the diagnosis of solid pancreatic lesions—A comparison of conventional ultrasound and contrast-enhanced CT

Objective

To explore the diagnostic value of contrast-enhanced ultrasound (CEUS) by comparison with conventional ultrasound (US) and contrast-enhanced CT (CECT) in solid pancreatic lesions.

Method

Ninety patients with solid pancreatic focal lesions were enrolled, including 36 cases of pancreatic carcinoma, 28 cases of pancreatitis, 6 cases of pancreatic neuroendocrine tumor, 12 cases of solid pseudopapillary tumor of the pancreas, 6 cases of pancreatic metastases, 1 case of cavernous hemolymphangioma and 1 case of lymphoma. US and CEUS were applied respectively for the diagnosis of a total of 90 cases of solid pancreatic lesions. The diagnostic results were scored on a 5-point scale. Results of CEUS were compared with CECT.

Results

(1) 3-score cases (undetermined) diagnosed by CEUS were obviously fewer than that of US, while the number of 1-score (definitely benign) and 5-score (definitely malignant) cases diagnosed by CEUS was significantly more than that of US. There was a significant difference in the distribution of final scores using the two methods (p < 0.001). The overall diagnostic accuracies of the 90 cases for CEUS and US were 83.33% and 44.44%, respectively, which indicated an obvious advantage for CEUS (p < 0.001). (2) The diagnostic consistency among three ultrasound doctors: the kappa values calculated for US were 0.537, 0.444 and 0.525, compared with 0.748, 0.645 and 0.795 for CEUS. The interobserver agreement for CEUS was higher than that for US. (3) The sensitivity, specificity and accuracy of the diagnosis of pancreatic carcinoma with CEUS and CECT were 91.7% and 97.2%, 87.0% and 88.9%, and 88.9% and 92.2%, respectively, while for the diagnosis of pancreatitis, the corresponding indices were 82.1% and 67.9%, 91.9% and 100%, and 88.9% and 90%, respectively, showing no significant differences (p > 0.05).

Conclusion

CEUS has obvious superiority over conventional US in the general diagnostic accuracy of solid pancreatic lesions and in the diagnostic consistency among doctors. The performances of CEUS are similar to that of CECT in the diagnosis of pancreatic carcinoma and focal pancreatitis.     

Focal liver lesions in cirrhosis: value of contrast-enhanced ultrasonography compared with Doppler ultrasound and α-fetoprotein levels

Purpose

This study aimed to evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) in characterising focal liver lesions in cirrhosis and to validate its use in lesions discovered during surveillance for hepatocellular carcinoma (HCC).

Materials and methods

Between 2003 and 2006, 128 cirrhotic patients with focal liver lesions at baseline ultrasonography (US) were studied by power colour Doppler US (Doppler US) and CEUS. Serum alpha-fetoprotein (AFP) levels were assessed in all patients. Fine-needle biopsy or other reference modalities such as computed tomography (CT), magnetic resonance imaging (MRI) or digital subtraction angiography (DSA) were used as the gold standard. The accuracy of baseline US, Doppler US, AFP levels, combined US and AFP levels and combined US, Doppler US and CEUS in characterising focal liver lesions was assessed. Diagnostic performance was compared using the McNemar test.

Results

A total of 207 focal liver lesions (101 benign and 106 malignant) were identified in 128 patients. CEUS sensitivity and specificity for lesion characterisation were 96.2% and 97.0%, respectively, whereas its positive and negative predictive values were 97.1% and 96.1%. CEUS accuracy was 96.6%, higher than that of US (72.0%), Doppler US (70.0%), AFP levels (65.7%), combined US and Doppler US (70.0%) and combined US and AFP levels (90.3%). The differences between US and CEUS were statistically significant (p<0.05).

Conclusions

CEUS can characterise focal liver lesions with 96.6% accuracy, a value higher than US, Doppler US, AFP levels, combined US and AFP levels and combined US and Doppler US. CEUS should therefore be used to characterise focal liver lesions detected during HCC surveillance of cirrhotic patients.     

Pretreatment Evaluation with Contrast-Enhanced Ultrasonography for Percutaneous Radiofrequency Ablation of Hepatocellular Carcinomas with Poor Conspicuity on Conventional Ultrasonography

Objective

To determine whether pretreatment evaluation with contrast-enhanced ultrasonography (CEUS) is effective for percutaneous radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC) with poor conspicuity on conventional ultrasonography (US).

Materials and Methods

This retrospective study was approved by the institutional review board and informed consent was waived. From June 2008 to July 2011, 82 patients having HCCs (1.2 ± 0.4 cm) with poor conspicuity on planning US for RFA were evaluated with CEUS prior to percutaneous RFA. We analyzed our database, radiologic reports, and US images in order to determine whether the location of HCC candidates on planning US coincide with that on CEUS. To avoid incomplete ablation, percutaneous RFA was performed only when HCC nodules were identified on CEUS. The rate of technical success was assessed. The cumulative rate of local tumor progression was estimated with the use of the Kaplan-Meier method (mean follow-up: 24.0 ± 13.0 months).

Results

Among 82 patients, 73 (89%) HCCs were identified on CEUS, whereas 9 (11%) were not. Of 73 identifiable HCCs on CEUS, the location of HCC on planning US corresponded with that on CEUS in 64 (87.7%), whereas the location did not correspond in 9 (12.3%) HCCs. Technical success was achieved for all 73 identifiable HCCs on CEUS in a single (n = 72) or two (n = 1) RFA sessions. Cumulative rates of local tumor progression were estimated as 1.9% and 15.4% at 1 and 3 years, respectively.

Conclusion

Pretreatment evaluation with CEUS is effective for percutaneous RFA of HCCs with poor conspicuity on conventional US.     

Focal liver lesions: can SonoVue-enhanced ultrasound be used to differentiate malignant from benign lesions?

OBJECTIVE: To evaluate whether contrast-enhanced ultrasound (CEUS) with SonoVue could differentiate malignant focal liver lesions (FLLs) from benign lesions and provide lesion type diagnoses. MATERIALS AND METHODS: Four hundred fifty-six patients with 554 FLLs were examined by CEUS with SonoVue using low mechanical index, nonlinear imaging techniques. Each lesion was characterized by 2 independent off-site readers as malignant or benign and given specific lesion type diagnosis, if possible, both at baseline ultrasound (US) and after SonoVue administration (CEUS). The final diagnosis was achieved by histopathology obtained from biopsy or surgical specimens, or by typical manifestation on contrast-enhanced CT or MRI. RESULTS: The diagnostic accuracies of the 2 readers were 41.9% and 35.2% for baseline US, which improved significantly to 87.2% and 87.9% for CEUS (P < 0.05). Interreader agreement also increased with CEUS compared with baseline US (ê value changed from 0.49 to 0.77). The accuracy for lesion type diagnosis was 38.4% and 32.5% for baseline US, which increased to 77.6% and 78.0% for CEUS (P < 0.05). CONCLUSIONS: CEUS with SonoVue improves differentiation between malignant and benign FLLs, and also provides improved lesion type (differential) diagnosis.     

Contrast enhanced gray-scale sonography in assessment of joint vascularity in rheumatoid arthritis: results from the IACUS study group

The purpose of this study way to assess the value of contrast enhanced gray-scale ultrasound (CEUS) in detection of vascularity in joints of patients with rheumatoid arthritis (RA) in a multicenter study of the International Arthritis Contrast Ultrasound (IACUS) study group. We assessed 113 joints in 113 patients (44 men, 69 women; mean age 51±14 years) with clinical diagnosis of RA. Gray-scale ultrasound (US), power Doppler US (PDUS) and CEUS, using a low mechanical index US technique, was performed. CEUS was done by bolus administration of the contrast agent SonoVue (Bracco, Milan, Italy) with a dosage of 4.8-ml SonoVue flushed with 10 ml saline. Detection of joint vascularity was performed for differentiation of active synovitis from inactive intra-articular thickening (synovitis/effusion). With the use of US and PDUS, active synovitis could be differentiated from inactive intra-articular thickening in 68/113 joints (60.1%), whereas CEUS enabled differentiation in 110/113 (97.3%) joints (p<0.0001). Thickness measurement of active synovitis was significantly improved after contrast administration (p=0.008). In conclusion, CEUS improves the differentiation of active synovitis from inactive intra-articular thickening. Since CEUS has shown an ability to improve assessment of vascularized synovial proliferation in RA affected joints, this technique may have further potential in monitoring therapy.     

Diagnostic performance of contrast-enhanced ultrasound for complex cystic focal liver lesions: blinded reader study

The study was aimed at evaluating the diagnostic performance of contrast-enhanced ultrasound (CEUS) in characterizing complex cystic focal liver lesions (FLLs). Sixty-seven complex cystic FLLs in 65 patients were examined with conventional ultrasound (US) and real-time CEUS. The US and CEUS images were reviewed by a resident radiologist and a staff radiologist independently. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance, and the interobserver agreement was analysed. The results showed that complete non-enhancement throughout three phases of CEUS or sustained enhancement in the portal and late phases were exhibited in most benign lesions. Conversely, hypo-enhancement in the late phase was seen in all malignancies. After ROC analysis, the areas (Az) under the ROC curve were 0.774 at US versus 0.922 at CEUS (P = 0.047) by the resident radiologist, and 0.917 versus 0.935 (P = 0.38) by the staff radiologist. A significant difference in Az between the resident and the staff radiologists was found for US (0.774 versus 0.917, P = 0.044), whereas not found for CEUS (0.922 versus 0.935, P = 0.42). Interobserver agreement was improved after CEUS (κ = 0.325 at US versus κ = 0.774 at CEUS). Real-time CEUS improves the capability of discrimination between benign and malignant complex cystic FLLs, especially for the resident radiologist.     

Detection and characterization of focal liver lesions with contrast-enhanced ultrasonography in patients with hepatitis C-induced liver cirrhosis

Background: Hepatitis C virus (HCV)-associated liver cirrhosis provides a major preneoplastic condition for hepatocellular carcinoma (HCC). Ultrasonography (US) is usually used for screening of HCC, but needs improvement.

Purpose: To assess whether use of a second-generation ultrasound contrast agent can improve characterization of focal liver lesions and detection of HCC in HCV-infected patients with liver cirrhosis.

Material and Methods: In total, 96 US studies in 49 HCV-infected patients with liver cirrhosis were performed. The patients were first examined with a baseline US. After this, a diagnostic decision was made and recorded. The patients were then re-examined with contrast-enhanced ultrasound (CEUS), and the diagnostic triage was repeated. The patients were followed up for at least 1 year.

Results: On baseline US, indeterminate focal lesions were found in 27 examinations. After CEUS, a confident diagnosis of HCC was made in eight of these examinations. In an additional eight US examinations, diagnosis of regenerative/dysplastic noduli was established. In one patient with no detectable focal lesion at baseline examination, an indeterminate malignant lesion was detected with CEUS. This lesion was further investigated with computed tomography and diagnosed as HCC.

Conclusion: Our study indicates that the use of CEUS significantly improves diagnostic confidence. CEUS improves the detection of HCC in patients with HCV-induced liver cirrhosis. Also, CEUS makes it possible to rule out malignancy in many cases where baseline US shows indeterminate focal lesions. In low-endemic countries, the use of CEUS in screening for HCC may be considered.     

Management of hepatocellular carcinoma: The role of contrast-enhanced Tultrasound简

Hepatocellular carcinoma (HCC) is the sixth most common neoplasm and the third cause of cancer death worldwide. Contrast enhanced ultrasound (CEUS) has been applied for more than ten years and plays increasingly important roles in the management of HCC. On the basis of the Guideline and Good Clinical Practice Recommendations for CEUS in the liver-update 2012 and related literature about the management of HCC, we summarize the main roles and applications of CEUS in the management of HCC, including HCC surveillance, diagnosis, CEUS-guided treatment, treatment response evaluation and follow-up. The diagnostic algorithm for HCC is also suggested. Meanwhile, the comparisons between CEUS and contrast enhanced computed tomography/magnetic resonance imaging (CECT/CEMRI) in these areas are made. Although CEUS is subject to the same limitation as ordinary US and is inferior to CECT/CEMRI in some aspects, CEUS has proved to be of great value in the management of HCC with inherent advantages, such as sufficient high safety profile making it suitable for patients with renal failure or allergic to iodine, absence of radiation, easy reproducibility and high temporal resolution. The tremendous application of CEUS to the diagnosis and treatment of HCC provides more opportunities for patients with HCC diagnosed at different stages.     

Role for contrast-enhanced ultrasound in assessing complications after kidney transplant

Kidney transplantation (KT) is an effective treatment for end-stage renal disease. Despite their rate has reduced over time, post-transplant complications still represent a major clinical problem because of the associated risk of graft failure and loss. Thus, post-KT complications should be diagnosed and treated promptly. Imaging plays a pivotal role in this setting. Grayscale ultrasound (US) with color Doppler analysis is the first-line imaging modality for assessing complications, although many findings lack specificity. When performed by experienced operators, contrast-enhanced US (CEUS) has been advocated as a safe and fast tool to improve the accuracy of US. Also, when performing CEUS there is potentially no need for further imaging, such as contrast-enhanced computed tomography or magnetic resonance imaging, which are often contraindicated in recipients with impaired renal function. This technique is also portable to patients’ bedside, thus having the potential of maximizing the cost-effectiveness of the whole diagnostic process. Finally, the use of blood-pool contrast agents allows translating information on graft microvasculature into time-intensity curves, and in turn quantitative perfusion indexes. Quantitative analysis is under evaluation as a tool to diagnose rejection or other causes of graft dysfunction. In this paper, we review and illustrate the indications to CEUS in the post-KT setting, as well as the main CEUS findings that can help establishing the diagnosis and planning the most adequate treatment.     

Contrast-enhanced US of hepatocellular carcinoma

PURPOSE: To evaluate the capabilities of contrast-enhanced ultrasound (CEUS) in the characterization of hepatocarcinoma (HCC) in terms of accuracy as compared to spiral CT and diagnostic gain as compared to conventional and Doppler US. MATERIALS AND METHODS: Forty-three patients with viral hepatopathy or cirrhosis diagnosed with HCC (6 histologically and 37 cytologically proven) were retrospectively studied. Between January 2002 and May 2003, all patients were evaluated with CEUS after detection of at least one suspicious nodule on US. CEUS features of HCCs were retrospectively compared with those on conventional and Doppler US, and spiral CT. RESULTS: HCCs varied between 1.2 cm and 18 cm in diameter; 14/43 were small' (< or = 2 cm). In 18/43 patients, HCC was multifocal. Doppler US revealed 24/43 hypervascular nodules. On CEUS, 37/43 (86%) showed contrast enhancement in the arterial phase, 13/37 (35%) with negative colour and power Doppler US examination; in 6/37 (16%) contrast enhancement in the arterial phase was not visible on spiral CT. On CEUS, 6/43 hypovascular HCCs were characterized as malignant in the sinusoidal phase. On CEUS, the sinusoidal phase revealed additional nodules not visible on baseline US in 3/18 multifocal HCCs. CONCLUSIONS: CEUS diagnosis of HCC in cirrhotic liver is possible with a combination of the arterial phase, which shows tumoral hypervascularity in the microcirculation, and the sinusoidal phase, which allows to confirm the malignancy of the nodule.     

Contrast enhanced ultrasound in the detection of liver metastases: a prospective multi-centre dose testing study using a perfluorobutane microbubble contrast agent (NC100100)

Objective

To conduct a dose testing analysis of perfluorobutane microbubble (NC100100) contrast-enhanced ultrasound (CEUS) to determine the optimal dose for detection of liver metastases in patients with extra-hepatic primary malignancy.

Methods

157 patients were investigated with conventional US and CEUS. CEUS was performed following intravenous administration of perfluorobutane microbubbles (using one dose of either 0.008, 0.08, 0.12 or 0.36 μL/kg body weight). Three blinded off-site readers recorded the number and locations of metastatic lesions detected by US and CEUS. Contrast enhanced CT and MRI were used as the “Standard Of Reference” (SOR). Sensitivity, specificity and accuracy of liver metastasis detection with US versus CEUS, for each dose group were obtained. Dose group analysis was performed using the Chi-square test.

Results

165 metastases were present in 92 patients who each had 1–7 lesions present on the SOR. Sensitivity of US versus CEUS (for all doses combined) was 38% and 67% (p?=?0.0001). The 0.12 dose group with CEUS (78%) had significantly higher sensitivity and accuracy (70%) compared to other dose groups (p?Conclusion The diagnostic performance of CEUS is dose dependent with the 0.12 μL/kg NC100100 dose group showing the greatest sensitivity and accuracy in detection of liver metastases.     

Pancreatic multicenter ultrasound study (PAMUS)

Aim

To describe the typical CEUS pattern of pancreatic lesions and to evaluate the diagnostic accuracy of Contrast-enhanced ultrasound (CEUS) in their characterization.

Materials and methods

All US and CEUS examinations of focal pancreatic masses performed in six centers during a period of five years were reviewed. Inclusion criteria were: focal pancreatic mass pathologically proved, visible at ultrasound (US) and studied with CEUS. All lesions were then evaluated for size, aspect and enhancement pattern. Sensitivity, specificity, positive and negative predictive values with 95% CIs were calculated to define diagnostic accuracy of CEUS in respect to pathology. Diagnostic confidence of US and CEUS, discerning between benign and malignant lesions, were represented by using ROC (receiver operating characteristics) curves. Agreement was evaluated by means of k statistics.

Results

1439 pancreatic lesions were included. At CEUS the lesions were divided into solid (89%) and cystic (12%) masses and classified into six and eight categories, respectively. Among the solid lesions, adenocarcinomas were characterized with an accuracy of 87.8%. Among the cystic lesions, cystic tumors were diagnosed with an accuracy of 97.1%. ROC curve area increased from 0.637 for US to 0.877 for CEUS (p < 0.0001). Inter-observer agreement was slightly higher for solid (k = 0.78) than cystic (k = 0.62) lesions. In none of the centers side effects were reported.

Conclusion

CEUS is accurate in the characterization of pancreatic lesions. CEUS should be considered as a complementary imaging method for pancreatic lesions characterization.     

Contrast enhanced ultrasound with second generation contrast agent in traumatic liver lesions

PURPOSE: To evaluate the accuracy of second generation contrast enhanced US (Sonovue) in the diagnosis and staging of traumatic hepatic lesions, compared with conventional US and spiral CT. MATERIAL AND METHODS: A total of 203 patients (127 males, 76 females, mean age 36 years) with isolated abdominal trauma were examined with conventional and contrast enhanced US (Sonovue, Bracco, Italy) between March 2002 and February 2003. The sonographic contrast agent was administered at a dose of 2 ml/10-15", repeated twice. CT examinations were performed with single- (Rhota, Esaote Biomedica, Italy) or multislice spiral CT with administration of contrast agent. The presence and number of lesions, hepatic capsular involvement, size and sonographic pattern were evaluated. RESULTS: Conventional US demonstrated hepatic lesions in 27 patients, in 3 cases it identified 2 foci (30 lesions, size 2-8 cm). Contrast enhanced US (CEUS) revealed another 2 lesions and in 4 patients it identified lesions not shown at conventional US (size 2-5 cm). Capsular involvement was detected in 14 cases (11 with conventional US). The sonographic pattern of the lesions at conventional US was hypo-anechoic in 19 cases, and hyperechoic in 11. In CEUS all the lesions appeared strongly hypoechoic against a strongly hyperechoic parenchyma, with clear borders and larger size as compared with conventional US. CONCLUSIONS: In isolated blunt abdominal trauma CEUS is more accurate than conventional US in determining the number and size of lesions and detecting capsular involvement. This has a strong impact on diagnosis as the number of false negatives is reduced and on prognosis as the lesions are more accurately graded, and there is close correlation with spiral CT. CEUS can be used as a first approach in mild isolated abdominal trauma, in paediatric patients and in the follow-up, whereas CT is the method of choice in severe trauma and in multiple traumas.     

Characterization of hypoechoic focal hepatic lesions in patients with fatty liver: diagnostic performance and confidence of contrast-enhanced ultrasound

The objective of this study was to assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) to characterize hypoechoic focal hepatic lesions (HFHL) in fatty liver (FL). A study group of 105 patients with FL and 105 HFHLs (52 malignant and 53 benign) underwent CEUS after SonoVue administration. Two blinded readers independently reviewed baseline ultrasound (US) and CEUS scans and classified each lesion as malignant or benign on a five-point scale of confidence, and recorded whether further imaging work-up was needed. Sensitivity, specificity, areas under the receiver operating characteristic (ROC) curve (A (z)), and interobserver agreement were calculated. We observed that the diagnostic confidence improved after reviewing CEUS scans for both readers (A (z)=0.706 and 0.999 and A (z)=0.665 and 0.990 at baseline US and CEUS, respectively; p<0.0001). Inter-reader agreement increased (weighted k=0.748 at baseline US vs. 0.882 at CEUS). For both readers, after CEUS, the occurrence of correctly characterized lesions increased (from 27/105 [27.5%] to 94/105 [89.5%], and from 19/105 [18.1%] to 93/105 [88.6%], respectively; p<0.0001) and the need for further imaging decreased (from 93/105 [88.6%] to 26/105 [24.8%], and from 96/105 [91.4%] to 40/105 [38.1%], respectively; p<0.0001). We conclude that CEUS improves the diagnostic performance of radiologists in the characterization of HFHLs in FL and reduces the need for further imaging work-up.     

Contrast-enhanced ultrasonography in the characterization of benign focal liver lesions: activity-based cost analysis

PURPOSE: The aim of this study was to perform a cost analysis of contrast-enhanced ultrasonography (CEUS) in the study of benign focal liver lesions (BFLL) with indeterminate appearance on ultrasonography (US). MATERIALS AND METHODS: A decision model of patients with suspected BFLL on baseline US who subsequently underwent CEUS between 2002 and 2005 was constructed. We analysed the cost effectiveness of CEUS, considering whether or not computed tomography (CT) was necessary for the diagnosis. There were 398 patients with 213 angiomas, 41 focal nodular hyperplasias (FNH) and 154 pseudolesions (focal fatty sparing, focal fatty areas). Each patient underwent CEUS, and 98 of them were also studied by CT. All lesions were followed up. RESULTS: The cost of a single CEUS examination was 101.51 euros, and that of a single CT scan was 211.48 euros. For diagnosis of haemangiomas, we saved 1,406.97 euros in 2002, 5,315.22 euros in 2003, 10,317.78 euros in 2004 and 9,536.13 euros in 2005. For diagnosis of focal nodular hyperplasias, we saved 781.65 euros in 2003, 781.65 euros in 2004 and 1,406.97 euros in 2005. For diagnosis of pseudolesions, we saved 2,813.94 euros in 2002, 5,158.89 euros in 2003, 5,158.89 euros in 2004 and 4,220.91 euros in 2005. In the period 2002-2005, the introduction of CEUS allowed us to save a total of 47,055.33 euros in the diagnosis of benign focal hepatic liver lesions. CONCLUSIONS: This cost analysis shows that CEUS is the least expensive second-line modality after baseline US for the diagnosis of BFLL.     

Comparison of contrast-enhanced ultrasonography versus baseline ultrasound and contrast-enhanced computed tomography in metastatic disease of the liver: diagnostic performance and confidence

Aim: The aim of this study was to compare contrast-enhanced ultrasonography (CEUS) to baseline US and contrast-enhanced computed tomography (CT) in metastatic disease of the liver diagnosed or suspected by US during presurgical staging or postsurgical follow-up for primary malignancies. Materials and methods: Two hundred-fifty-three patients considered suitable for US due to the complete explorability of the liver and with one to five proven or suspected liver metastases at baseline US were included. All patients underwent US before and after microbubble injection, and multiphase contrast-enhanced CT. Independent panels of readers reviewed US and CT scans and recorded liver metastases according to a 5-grade scale of diagnostic confidence. Sensitivity, specificity (diagnostic performance) and area under the receiver operating characteristics (ROC) curve (diagnostic confidence) were calculated. Results: Reference standards revealed no metastases in 57/253, more than five in 59/253, and one to five in 137/253 patients. In patients with one to five metastases, CEUS versus baseline US revealed more metastases in 64/137 and the same number in 73/137 patients while CEUS versus CT revealed more metastases in 10/137, the same number in 99/137, and lower number in 28/137. Sensitivity, specificity, and area under ROC curve of CEUS (83%, 84%, 0.929, respectively) differed from baseline US (40%, 63%, 0.579, respectively; P<0.01) while did not differ from CT (89%, 89%, 0.945, respectively; P>0.05). Conclusion: CEUS improved liver metastases diagnosis in comparison with baseline US while it revealed similar diagnostic performance and confidence to contrast-enhanced CT in patients considered suitable for US and with proven or suspected liver metastases at baseline US.     

Differentiating benign from malignant solid breast lesions: Combined utility of conventional ultrasound and contrast-enhanced ultrasound in comparison with magnetic resonance imaging

Objective

To prospectively evaluate the diagnostic efficacy of conventional ultrasound (US), contrast-enhanced US (CEUS), the combined use of two modalities, and magnetic resonance imaging (MRI) in the differentiation of focal solid breast lesions.

Materials and methods

61 patients with BI-RADS category 3–5 breast lesions detected at conventional US underwent CEUS and MRI. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of conventional US, CEUS, combination of two modalities and MRI for discrimination between benign and malignant breast lesions.

Results

Tissue specimens of 61 breast lesions were obtained either from surgical resection (n = 46) or from needle biopsy (n = 15). Histopathologic diagnosis revealed 28 benign and 33 malignant lesions. The diagnostic performance of conventional US and CEUS in differentiating benign from malignant breast lesions showed no significant difference (P = 0.741). The combination of two modalities significantly improved the diagnostic accuracy compared with either conventional US or CEUS alone (P = 0.031 and P = 0.012, respectively). The area under the ROC curve (A_z) value for the combined use of two modalities for discrimination between benign and malignant breast lesions was 0.94, and that for MRI was 0.91, whereas no statistical difference was found between them (P = 0.296).

Conclusion

The combined use of conventional US and CEUS has a better diagnostic performance than either method alone and displays good agreement with MRI in the differentiation capability for benign and malignant breast lesions.