Nonpalpable breast lesions: evaluation with power Doppler US and a microbubble contrast agent-initial experience

PURPOSE: To evaluate power Doppler ultrasonography (US) performed with a microbubble US contrast agent in the differentiation of nonpalpable breast lesions. MATERIALS AND METHODS: Fifty nonpalpable breast lesions in 50 patients were prospectively evaluated with power Doppler US before and after injection of the contrast agent SH U 508A. Lesion vascularity and the morphology of vessels on US scans were analyzed and were correlated with histologic results. RESULTS: Surgical excision revealed 22 cancers and 28 benign lesions. At nonenhanced power Doppler US, eight (36%) of 22 cancers and four (14%) of 28 benign lesions were vascular. At contrast agent-enhanced power Doppler US, 21 (95%) cancers and six (21%) benign lesions were vascular (P <.001). Irregular vessels were seen in three cancers and one benign lesion at nonenhanced power Doppler US and in 11 cancers and one benign lesion at contrast-enhanced power Doppler US. By using the presence of vascularity in the mass as the diagnostic criterion for malignancy, the sensitivity, specificity, and positive and negative predictive values of power Doppler US changed from 36%, 86%, 67%, and 63%, respectively, to 95%, 79%, 78%, and 96% after contrast agent injection. CONCLUSION: Contrast-enhanced power Doppler US was superior to nonenhanced power Doppler US in the demonstration and characterization of tumor vascularity in nonpalpable breast lesions. Contrast-enhanced power Doppler US may be useful for the differentiation between nonpalpable breast cancers and benign tumors.     

Hepatocellular carcinoma treated with percutaneous radio-frequency ablation: usefulness of power Doppler US with a microbubble contrast agent in evaluating therapeutic response-preliminary results

PURPOSE: To evaluate the usefulness of power Doppler ultrasonography (US) with a microbubble contrast agent in assessing the therapeutic response of hepatocellular carcinomas (HCCs) treated with percutaneous radio-frequency (RF) ablation. MATERIALS AND METHODS: Forty patients with 45 nodular HCC lesions 1.0-3.8 cm in diameter underwent power Doppler US before and after intravenous injection of a microbubble contrast agent. The same procedures were repeated after US-guided percutaneous RF ablation. The results of these studies were compared with those of three-phase helical computed tomography (CT) performed immediately after RF ablation. RESULTS: Before RF ablation, nonenhanced power Doppler US demonstrated flow signals within tumor in 33 of 45 HCCs. After contrast agent administration, flow signals increased or newly appeared in all cases. After RF ablation, none of the ablated tumors showed intratumoral flow signals at nonenhanced power Doppler US, whereas six showed marginal intratumoral flow signals at contrast agent-enhanced power Doppler US. These six tumors were found to have small enhancing foci, suggestive of viable tumor, in corresponding areas at immediate follow-up CT. Additional RF ablation or transcatheter arterial chemoembolization was performed in these tumors. CONCLUSION: The results of power Doppler US with a microbubble contrast agent in HCCs treated with RF ablation correlated well with those of contrast-enhanced CT. Preliminary data suggest that contrast-enhanced power Doppler US can be a promising noninvasive technique for assessing therapeutic response.     

Kinetics of a US contrast agent in benign and malignant adnexal tumors

PURPOSE: To evaluate the effects of a microbubble contrast agent on the power Doppler ultrasonographic (US) examination of adnexal tumors, with a special focus on the timing of the transit of the microbubble bolus. MATERIALS AND METHODS: Seventy patients who were suspected of having ovarian tumors were examined preoperatively with contrast material-enhanced US. Images obtained during a 5-minute examination were stored digitally, and the behavior of the contrast agent was evaluated objectively with measurement of the time-dependent image intensity at the region of interest with a computer program. A time-intensity curve in each case was derived and analyzed. The Mann-Whitney U test was used to compare intensity changes and tumor parameters in benign and malignant adnexal tumors. RESULTS: Both the baseline and maximum power Doppler intensities, as well as the absolute and relative (percent) rise in intensity, were significantly higher (P <.001) in malignant as compared with benign tumors. The arrival time was shorter (17.5 vs 22.5 seconds; P =.005) and the duration of contrast agent effect was longer (190.4 vs 103.6 seconds; P <.001) in malignant tumors than they were in benign tumors. The area under the time-intensity curve was significantly greater in malignant tumors compared with that in benign tumors (P <.001). CONCLUSION: After microbubble contrast agent injection, malignant and benign adnexal lesions behave differently in degree, onset, and duration of Doppler US enhancement.     

Radiofrequency thermal ablation of hepatocellular carcinoma: using contrast-enhanced harmonic power doppler sonography to assess treatment outcome

OBJECTIVE: We evaluated the accuracy of contrast-enhanced harmonic power Doppler sonography in assessing the outcome of radiofrequency thermal ablation of hepatocellular carcinoma. SUBJECTS AND METHODS: Fifty patients with 65 hepatocellular carcinoma nodules (1-5 cm in diameter; mean diameter, 2.5 cm) were studied using unenhanced and contrast-enhanced harmonic power Doppler sonography before and after IV administration of a microbubble contrast agent. The examinations were repeated after treatment of the tumors with radiofrequency ablation. Findings of the Doppler studies were compared with those of dual-phase helical CT, which were used as points of reference for assessing treatment outcome. RESULTS: Before radiofrequency treatment, intratumoral blood flow was revealed by unenhanced power Doppler sonography in 48 (74%) of 65 hepatocellular carcinoma nodules. After injection of the contrast agent, intratumoral enhancement was observed in 61 (94%) of 65 hepatocellular carcinomas (p < 0.01). After radiofrequency treatment, all 51 (84%) of the 61 hepatocellular carcinomas found to be necrotic on helical CT scans failed to show enhancement on power Doppler sonograms. In nine of the 10 lesions that showed a residual viable tumor on helical CT scans, persistent intratumoral enhancement-matching the enhancing areas on helical CT images-was revealed by power Doppler sonography. These nine hepatocellular carcinomas were subjected to repeated radiofrequency thermal ablation with the guidance of contrast-enhanced power Doppler sonography. Complete necrosis was seen after the second treatment session in six of the nine lesions. CONCLUSION: Contrast-enhanced harmonic power Doppler sonography is an accurate technique for assessing the outcome of radiofrequency thermal ablation of hepatocellular carcinoma and may be useful in guiding additional treatment in patients with incomplete response to initial efforts.     

Contrast-enhanced color Doppler ultrasound characteristics in hypervascular breast tumors: comparison with MRI

The aim of this study was to evaluate the accuracy of contrast-enhanced color Doppler ultrasound (CE-US) in comparison with contrast-enhanced MR imaging (CE-MRI) in the discrimination of hypervascularized breast tumors. An additional CE-US of the breast was preoperatively performed in 40 patients with a hypervascular breast lesion detected on CE-MRI. The presence of blood flow signals and the morphological characteristics of the vessels in the breast lesions were evaluated pre- and post-contrast administration, as well as the dynamic aspects of the Doppler signal, including time interval to maximum signal enhancement and persistence of the signal enhancement. Twenty-three carcinomas and 17 fibroadenomas were explored. Considering initial signal enhancement > 100 % after the administration of contrast material as a criterion suggesting malignancy, CE-MRI showed a sensitivity of 100 % and a specificity of 76.5 % in the detection of malignant breast tumors. Color Doppler signals were consistently demonstrated in all carcinomas and in 68.7 % of fibroadenomas after the administration of Levovist, with CE-US showing a sensitivity of 95.6 % and a specificity of 5.9 %. Neither the mean number of vessels per tumor, nor the location of vessels, the time to maximum increase of the Doppler signal or the persistence of signal enhancement showed significant differences between benign and malignant lesions. Additional CE-US does not increase the low specificity of MRI in patients with hypervascularized breast tumors. Received: 17 July 2000 Revised: 22 August 2000 Accepted: 24 August 2000     

能量多普勒和三维血管重建在乳腺肿瘤诊断中的应用研究

目的:研究乳腺肿块能量多普勒显像和三维血管重建血流灌注及形态特征的变化。方法:171例乳腺肿块,选用能量多普勒和三维血管重建对照,观察血流程度变化、血流形态特征,定量分析彩色血流灌注面积。结果:三维血管重建显示乳腺癌和良性肿块血流信号比能量多普勒有显著增强效果,两者差异有显著性(P<0.05)。乳腺癌灌注面积显著大于良性肿块,两者差异有显著性(P<0.05)。结论:三维血管重建能有效增强乳腺肿块的血流信号,能量多普勒和三维血管重建对照能显著提高乳腺肿瘤鉴别诊断的价值。     

Evaluation of tumor angiogenesis with a second-generation US contrast medium in a rat breast tumor model.

OBJECTIVE: Tumor angiogenesis is an important factor for tumor growth, treatment response and prognosis. Noninvasive imaging methods for the evaluation of tumor angiogenesis have been studied, but a method for the quantification of tumor angiogenesis has not been established. This study was designed to evaluate tumor angiogenesis in a rat breast tumor model by the use of a contrast-enhanced ultrasound (US) examination with a second-generation US contrast agent. MATERIALS AND METHODS: The alkylating agent 19N-ethyl-N-nitrosourea (ENU) was injected into the intraperitoneal cavity of 30-day-old female Sprague-Dawley rats. Three to four months later, breast tumors were detected along the mammary lines of the rats. A total of 17 breast tumors larger than 1 cm in nine rats were evaluated by gray-scale US, color Doppler US and contrast-enhanced US using SonoVue. The results were recorded as digital video images; time-intensity curves and hemodynamic parameters were analyzed. Pathological breast tumor specimens were obtained just after the US examinations. The tumor specimens were stained with hematoxylin and eosin (H & E) and the expression of CD31, an endothelial cell marker, was determined by immunohistochemical staining. We also evaluated the pathological diagnosis of the tumors and the microvessel density (MVD). Spearman's correlation and the Kruskal-Wallis test were used for the analysis. RESULTS: The pathological diagnoses were 11 invasive ductal carcinomas and six benign intraductal epithelial proliferations. The MVD did not correlate with the pathological diagnosis. However, blood volume (BV) showed a statistically significant correlation with MVD (Spearman's correlation, p < 0.05). CONCLUSION: Contrast-enhanced US using a second-generation US contrast material was useful for the evaluation of tumor angiogenesis of breast tumors in the rat.     

Contrast-enhanced ultrasonography compared to gray-scale and power doppler in the diagnosis of peripheral lymphadenopathy

Objectives

The aim of the study was to evaluate the ability of contrast-enhanced ultrasonography compared to gray-scale B-mode and power Doppler in distinction between benign and malignant lymphadenopathy.

Methods

In a prospective study ultrasonography was performed in 133 patients with superficial lymphadenopathy (73 men, 60 women; mean age of 51 years, range: 18–86 years), who were examined for palpable mass in the neck, axilla or groin (104/133) and for clinical suspicion of lymphoma on the basis of positive PET/CT (29/133). 133 nodes were examined, subsequently preoperatively localized under ultrasound guidance and surgically removed; longitudinal to transverse ratio, location of nodal vessels by power Doppler and pattern of enhancement by contrast-enhanced ultrasonography with 1.5 ml intravenous bolus of sulphur hexafluoride contrast agent were documented. The ultrasound findings were compared with the histology.

Results

Of all the nodes extirpated, 33 were benign, 100 were malignant (40 metastases, 60 lymphomas). Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of conventional techniques were 72%, 63.6%, 85.7%, 42.9%, 67.8% for longitudinal to transverse ratio; 73%, 60.6%, 84.9%, 42.6%, 68.3% for power Doppler versus 98.0%, 54.5%, 86.7%, 90.0%, 76.3% for contrast-enhanced ultrasonography according to Receiver Operating Characteristic analysis.

Conclusions

Receiver Operating Characteristic analysis confirmed higher degree of diagnostic accuracy of contrast-enhanced ultrasonography in comparison with conventional techniques. Evaluation of nodal perfusion after intravenous administration of microbubble contrast agent can be helpful in differentiation of benign from malignant nodes.     

Quantitative assessment of synovial vascularity using contrast-enhanced power Doppler ultrasonography: correlation with histologic findings and mr imaging findings in arthritic rabbit knee model

OBJECTIVE: To validate contrast-enhanced power Doppler ultrasonography (PD US) for the evaluation of synovial vascularity in an arthritic rabbit knee model in correlation with MR and histological findings. MATERIALS AND METHODS: Power Doppler ultrasonography was performed for carrageenin-induced arthritic left knee and control right knee of 13 rabbits, first without and then with sonic contrast agent enhancement (Levovist, Schering, Berlin Germany), followed by gadolinium-enhanced MR imaging. Synovial vascularity was quantitatively assessed by calculating the color pixel area in power Doppler sonography using a computer-aided image analysis program and by grading the enhancement on MR images: grade 1, enhancement of knee joint is less than one-third of the area; grade 2, one-third to two-thirds enhancement; and grade 3, more than two-thirds enhancement. Microvessel density (MVD) was measured on slides stained immunohistochemically for CD31 antigen for histological assessment. RESULTS: The mean area of color pixels in PD US changed from 4.37 to 16.42 mm(2) in the arthritic knee after enhancement (p < 0.05), whereas it changed from 0.77 to 2.31 mm(2) in the control knee (p < 0.05). Arthritic knees had greater power Doppler signal than control knees both before and after contrast administration (p < 0.05). The average MVD was 88 in arthritic knees and 46 in control knees. MVDs correlated with color pixel areas of contrast-enhanced power Doppler imaging in arthritic knees. In MR grading of arthritic knees, five were grade 2 and eight were grade 3. MVD and PD US revealed no significant difference between grade 2 and 3 arthritic knees (p > 0.05). CONCLUSION: Sonic contrast-enhanced PD US improves the visualization of synovial vascularity and allows quantitative measurement in experimentally induced rabbit arthritic knees.     

Characterization of focal liver lesions with contrast-specific US modes and a sulfur hexafluoride-filled microbubble contrast agent: diagnostic performance and confidence

PURPOSE: To assess whether characterization of solid focal liver lesions could be improved by using ultrasonographic (US) contrast-specific modes after sulfur hexafluoride-filled microbubble contrast agent injection, as compared with lesion characterization achieved with preliminary baseline US. MATERIALS AND METHODS: Four hundred fifty-two solid focal hepatic lesions that were considered indeterminate at baseline gray-scale and color Doppler US were examined after microbubble contrast agent injection performed by using low-acoustic-power contrast-specific modes during the arterial (10-40 seconds after injection), portal venous (50-90 seconds after injection), and late (100-300 seconds after injection) phases. Two readers independently and retrospectively reviewed baseline and contrast material-enhanced US scans and classified each depicted lesion as malignant or benign according to standard diagnostic criteria. Sensitivity, specificity, accuracy, and positive and negative predictive values and areas under the receiver operating characteristic curve (Az) were calculated by considering histologic analysis (317 patients) or contrast-enhanced helical computed tomography followed by serial US 3-6 months apart (135 patients) as the reference standards. RESULTS: Different contrast enhancement patterns were observed according to lesion characteristics. During the late phase, benign lesions were predominantly hyper- or isoechoic relative to the adjacent liver parenchyma, whereas malignant lesions were predominantly hypoechoic. Review of the contrast-enhanced US scans after baseline image review yielded significantly improved diagnostic performance (P <.05). Overall diagnostic accuracy was 49% before versus 85% after review of the contrast-enhanced scan for reader 1 and 51% before versus 88% after review of the contrast-enhanced scan for reader 2. Diagnostic confidence-that is, the Az-was 0.820 before versus 0.968 after review of the contrast-enhanced scan for reader 1 and 0.831 before versus 0.978 after review of the contrast-enhanced scan for reader 2. CONCLUSION: The use of contrast-specific modes with a sulfur hexafluoride contrast agent led to improved characterization of solid focal liver lesions.     

Radio-frequency ablation of VX2 rabbit tumors: assessment of completeness of treatment by using contrast-enhanced harmonic power Doppler US

PURPOSE: To assess contrast material-enhanced harmonic power Doppler and fundamental color Doppler ultrasonography (US) in the detection of residual viable tumor tissue after radio-frequency (RF) ablation in tumors embedded in fat. MATERIALS AND METHODS: Twenty-eight VX2 tumors were implanted into the retroperitoneum of 14 rabbits. Tumors were examined with contrast-enhanced fundamental color Doppler US and harmonic power Doppler US before and 10 minutes after RF ablation. Saline-enhanced RF ablation (30 mL/h) was performed over 10 minutes with 28-W RF power. Follow-up included repeat US examinations. Necropsies and histopathologic assessment were performed after detection of residual untreated tumor at US or 3 weeks after ablation. RESULTS: VX2 tumors reached a mean size of 21 mm +/- 9 (SD) (size range, 6-43 mm) 25 days after implantation. All tumors larger than 31 mm showed signs of central necrosis at US. Before ablation, intense vascularity was detected in all tumors with both contrast-enhanced US modes. Histopathologic assessment at the end of the follow-up period revealed local relapses due to incomplete ablation in 14 (50%) of 28 cases. Detection of residual tumor was missed in all cases with contrast-enhanced color Doppler US. Contrast-enhanced harmonic power Doppler US depicted residual flow in 12 of the 14 cases (sensitivity, 86%) in which local relapses occurred. There was a significant (P <.005, McNemar test) improvement in detection of residual tumor when the harmonic power Doppler mode was used. CONCLUSION: Contrast-enhanced harmonic power Doppler US has greater sensitivity than contrast-enhanced color Doppler US for detecting residual VX2 tumor following ablation. Therefore, contrast-enhanced harmonic power Doppler US may be a useful additional method for the detection of residual tumors after RF ablation.     

Noninvasive assessment of renal artery stenosis: current imaging protocols and future directions in ultrasonography

Doppler ultrasound is one of many modalities that have been evaluated for the detection of renal artery stenosis. The lack of standardization in examination protocols and diagnostic criteria, as well as the wide differences in reported accuracy among different laboratories have, however, prevented universal acceptance of this technique as a reliable screening test for renal artery stenosis. The recent introduction of ultrasound contrast agents has substantially expanded the potential of color Doppler ultrasound. The use of microbubble echoenhancers in combination with harmonic Doppler imaging has been shown to improve diagnostic confidence by improving the operator's ability to visualize the renal arteries, and to significantly reduce the number of equivocal examinations. Moreover, contrast-enhanced Doppler ultrasound can provide functional information through analysis of renal time-intensity wash in/wash out curves. State-of-the-art contrast-enhanced Doppler ultrasound seems to have the potential to become a useful screening test for patients at risk from renovascular hypertension.     

乳腺肿瘤高频彩超及超声造影与微血管密度的相关性

目的 分析乳腺良恶性肿瘤高频彩超、超声造影(CEUS)与微血管密度(MVD)的相关性,探讨超声造影对乳腺肿瘤的诊断价值.资料与方法 82例原发性乳腺肿瘤患者于术前行常规高频彩超检查,观察病灶灰阶图像特征及血流特征;启动造影模式行实时灰阶谐波超声造影检查,应用时间-信号强度曲线分析软件分析病灶增强达峰时间(TTP)、峰值强度(PI)、曲线下面积(AUC);采用免疫组化测定肿瘤内MVD,分析超声造影定量参数与MVD的相关性.结果 恶性组肿瘤血流Adler分级低于良性组(P＜0.05);超声造影显像特点:恶性组血管数量多且粗细不等,良性组血流束细窄、平直;恶性组TTP低于良性组,PI及AUC高于良性组(P＜0.05),MVD显著高于良性组(P＜0.001);肿瘤MVD计数随血流Adler分级升高而升高,CDF1血流丰富程度与MVD呈正相关(r=0.456,P＜ 0.01); PI与MVD呈显著正相关(r=0.783,P＜0.01).结论 超声造影能客观评价乳腺肿瘤血供,术前应用CDFI结合超声造影在体检查肿瘤血管,可为早期诊断乳腺肿瘤提供信息.     

Quantitative evaluation of contrast-enhanced ultrasound after intravenous administration of a microbubble contrast agent for differentiation of benign and malignant thyroid nodules: assessment of diagnostic accuracy

Objectives

To investigate the diagnostic accuracy, through quantitative analysis, of contrast-enhanced ultrasound (CEUS), using a microbubble contrast agent, in the differentiation of thyroid nodules.

Methods

This prospective study enrolled 46 patients with solitary, scintigraphically non-functional thyroid nodules. These patients were scheduled for surgery and underwent preoperative CEUS with pulse-inversion harmonic imaging after intravenous microbubble contrast medium administration. Using histology as a standard of reference, time–intensity curves of benign and malignant nodules were compared by means of peak enhancement and wash-out enhancement relative to the baseline intensity using a mixed model ANOVA. ROC analysis was performed to assess the diagnostic accuracy in the differentiation of benign and malignant nodules on CEUS.

Results

The complete CEUS data of 42 patients (31/42 [73.8%] benign and 11/42 [26.2%] malignant nodules) revealed a significant difference (P < 0.001) in enhancement between benign and malignant nodules. Furthermore, based on ROC analysis, CEUS demonstrated sensitivity of 76.9%, specificity of 84.8% and accuracy of 82.6%.

Conclusions

Quantitative analysis of CEUS using a microbubble contrast agent allows the differentiation of benign and malignant thyroid nodules and may potentially serve, in addition to grey-scale and Doppler ultrasound, as an adjunctive tool in the assessment of patients with thyroid nodules.

Key Points

• Contrast-enhanced ultrasound (CEUS) helps differentiate between benign and malignant thyroid nodules.

• Quantitative CEUS analysis yields sensitivity of 76.9% and specificity of 84.8%.

• CEUS may be a potentially useful adjunct in assessing thyroid nodules.

     

彩色多普勒超声与MR诊断乳腺病变的临床价值分析

目的：比较彩色多普勒超声、磁共振动态增强对乳腺病变的临床诊断价值。方法收集经手术与病理证实的95例同时做过超声与M R的101个乳腺病灶,对其二维声像图及CDFI特点与磁共振动态增强影像学表现,对照病理结果进行回顾性分析。结果彩色多普勒与MR动态增强扫描对乳腺良恶性病变定性诊断准确率分别为：超声良性病变诊断正确率73．3％,恶性病灶诊断正确率87．3％;M R良性病变诊断正确率84．3％,恶性病灶诊断正确率92．7％。95个患者共检出101处病灶,其中乳腺癌67例,占66％;纤维瘤23例,占23％,炎性肉芽肿4例,占4％;分叶状肿瘤2例,占2％;囊腺瘤1例,占1％;乳头状瘤4例,占4％。结论超声检查诊断准确性高,适用于乳腺疾病的常规检查;MR空间分辨力及软组织分辨力高,适用于超声检查难以定性的病变及乳腺癌的术前评估。     

联合应用彩超、钼靶、MRI对早期乳腺癌的诊断价值

 目的 探讨联合应用彩超、钼靶、MRI对早期乳腺癌的诊断价值。方法 回顾性分析2018-01至2019-10医院收治的118例术前完善了彩超、钼靶、MRI检测的早期乳腺癌可疑患者的临床资料,以术后病理诊断为金标准,比较彩超、钼靶、MRI与三者联合检测的灵敏度、特异度和准确率。结果 118例患者中,术前检测可疑为乳腺癌:彩超87例,钼靶88例,MRI 92例,三者联合检测103例;术前检测乳腺良性病变:彩超31例,钼靶33例,MRI26例,三者联合检测15例;术后病理诊断乳腺癌106例,乳腺良性病变12例。灵敏度分别为:彩超79.25％,钼靶80.19％,MRI 84.91％,三者联合97.17％;特异度分别为:彩超75.00％,钼靶75.00％,MRI 83.33％,三者联合100.00％;准确率分别为:彩超78.81％,钼靶79.66％,MRI 84.75％,三者联合97.46％。在灵敏度、特异度和准确率方面,彩超、钼靶、MRI三者联合检测高于各单项检测,差异有统计学意义(P<0.05)。结论 联合应用彩超、钼靶、MRI检测早期乳腺癌,在灵敏度、特异度和准确率方面有较大提升。     

Microbubble ultrasound contrast in the assessment of hepatic artery patency following liver transplantation: role in reducing frequency of hepatic artery arteriography

We prospectively evaluated the role of microbubble ultrasound contrast for detection of hepatic artery thrombosis following liver transplantation. The hepatic artery of adult liver transplant recipients with suspected thrombosis on surveillance Doppler ultrasound (US) were re-examined by a second observer. In patients with no hepatic spectral Doppler signal the microbubble contrast agent Levovist was used. The presence or absence of flow following microbubble contrast was evaluated against arteriography or repeated Doppler US findings. A total of 794 surveillance Doppler US examinations were performed in 231 patients. Hepatic artery flow was demonstrated in 759 of 794 (95.6%) examinations. Microbubble ultrasound contrast was administered in 31 patients (35 studies) with suspected hepatic artery thrombosis. Following microbubble US contrast the hepatic artery could not be demonstrated in 13 of 35 (37.1%) studies (12 patients). Eight patients had arteriography: there was hepatic artery thrombosis in 7 patients and 1 patient had a patent, highly attenuated artery. Detection of a patent hepatic artery increased from 759 of 794 (95.6%) to 781 of 794 (98.4%) with the addition of microbubble contrast. Upon independent reading of the data, the degree of operator confidence in the assessment of the hepatic artery patency prior to microbubble contrast was 4.7 (CI 1.92–7.5) but rose to 8.45 (CI 7.06–9.84) following microbubble contrast (p<0.0001). In 22 of 35 (62.9%) of studies arteriography could potentially have been avoided. Ultrasound microbubble contrast media may reduce the need for invasive arteriography in the assessment of suspected hepatic artery thrombosis.     

Prospective evaluation of vascular complications after liver transplantation: comparison of conventional and microbubble contrast-enhanced US

PURPOSE: To prospectively compare diagnostic performance of conventional Doppler ultrasonography (US) and microbubble contrast material-enhanced US for assessment of vascular complications after liver transplantation, with clinical follow-up or angiography as reference standard. MATERIALS AND METHODS: This study was approved by institutional review board and was HIPAA compliant. Written informed consent was obtained. Seventy-two patients (49 men, 23 women; average age, 52.3 years) were included in this study. Patients who had undergone liver transplantation underwent conventional color Doppler and contrast-enhanced US of the liver. Quality of hepatic artery (HA) and portal vein (PV) visualization, contrast material arrival time, and time for complete evaluation of vasculature were compared for both techniques. McNemar test was used to compare vascular flow visualization scores; Student t test was used to compare mean study times with both techniques. Patients without HA flow at Doppler US underwent angiography; those with flow were followed up clinically. McNemar test was used to compare sensitivity of both techniques. RESULTS: Contrast-enhanced US helped significantly improve flow visualization in hepatic vessels (P < .001). Mean contrast material arrival time was 13.7 seconds +/- 3.8 (standard deviation) in proper HA and 20.7 seconds +/- 6.3 in PV. Mean study time decreased from 27.4 minutes +/- 13.9 to 9.3 minutes +/- 4.5 (P < .01). Doppler US failed to depict HA flow in eight patients; contrast-enhanced US showed flow in six and no flow in two of these patients. Follow-up results confirmed contrast-enhanced US findings. Sensitivity, specificity, and accuracy for Doppler US were 91.3%, 100%, and 91.5%, respectively. Sensitivity, specificity, and accuracy of contrast-enhanced US were all 100%. Sensitivity and accuracy values of the two techniques were significantly different (P < .014); there was no significant difference in specificity (P > .99) CONCLUSION: Contrast-enhanced US helped improve flow visualization in the HA and PV, decrease scanning time, and correctly differentiate between thrombosis and a patent artery in patients without HA flow at conventional Doppler US.     

Comparing dynamic parameters of tumor vascularization in nude mice revealed by magnetic resonance imaging and contrast-enhanced intermittent power Doppler sonography

RATIONALE: Angiogenesis is essential for spread and growth of malignant tumors. Because noninvasive methods for observing tumor vascularization are limited, most of previous results were based on histologic findings alone. In this study, dynamic parameters obtained using intermittent contrast-enhanced Doppler sonography and dynamic MRI were compared and correlated with microvessel density. METHODS: Eleven tumor-bearing nude mice were examined with dynamic T(1)-weighted sequences using Gd-DTPA in a 1.5 T magnetic resonance (MR) scanner and with intermittent power Doppler sonography after a single bolus of galactose based contrast agent. After examination 6 tumors were harvested for immunofluorescence microscopy using a CD31 stain. Using a 2-compartment model, the MR parameters amplitude (reflecting plasma volume) and k(ep) (influenced by the vessel permeability) were calculated and compared with maximal enhancement (max) and perfusion P measured with ultrasound. RESULTS: The MR amplitude correlated with the ultrasound parameter max significantly (r = 0.61; P = 0.01). Max (r = 0.67; P = 0.01), amplitude (r = 0.72; P = 0.01), and perfusion (r = 0.62; P = 0.05) correlated with the microvessel density. k(ep) moderately correlated with max, but not with perfusion and microvessel density. CONCLUSIONS: Dynamic MRI and contrast enhanced ultrasound are supplementing methods for examining perfusion and vascularity of experimental tumors.     

Contrast-enhanced ultrasonographic spoke-wheel sign in hepatic focal nodular hyperplasia

BACKGROUND: To determine the utility of contrast-enhanced ultrasonography (CEUS) in assessing hepatic tumors with central feeding arteries found by color/power Doppler ultrasonograophy (CDUS/PDUS). METHODS: We prospectively studied 37 hepatic tumors (34 patients), with a mean size of 2.9cm and each having a central feeding artery, by CDUS/PDUS. The CEUS was performed with a galactose-based microbubble contrast agent. The detection of a spoke-wheel sign was interpreted as evidence of focal nodular hyperplasia (FNH). All patients underwent tumor biopsies or surgical resection. RESULTS: CEUS showed a central feeding artery with a spoke-wheel sign in 36 tumors, including 34 FNHs and 2 hepatocellular carcinomas. The remaining tumor was demonstrated to be FNH despite the absence of a spoke-wheel sign as detected by CEUS. The sensitivity of the spoke-wheel sign or central scar for FNH was 97.1% (34/35), 40% (14/35), 28.6% (10/35), 50% (8/16) and 0% (0/15) for CEUS, CDUS/PDUS, dynamic computed tomography (CT) or magnetic resonance imaging (MRI), hepatic angiography and liver scintigraphy, respectively. The two hepatocellular carcinomas showed scirrhous changes histologically. CONCLUSIONS: CEUS is more sensitive than CDUS/PDUS, dynamic CT, MRI, hepatic angiography and liver scintigraphy in the detection of the spoke-wheel sign or central scar in FNH. Scirrhous hepatocellular carcinoma should be included in the differential diagnosis for liver tumors with spoke-wheel sign detected by CEUS.