Contrast-enhanced Doppler Ultrasonography Research Articles

Effects of contrast-enhanced ultrasound treatment on neoadjuvant chemotherapy in breast cancer.

Purpose: Preclinical and clinical data indicate that contrast-enhanced ultrasound can enhance tumor perfusion and vessel permeability, thus, improving chemotherapy accumulation and therapeutic outcome. Therefore, we investigated the effects of high mechanical index (MI) contrast-enhanced Doppler ultrasound (CDUS) on tumor perfusion in breast cancer.Methods: In this prospective study, breast cancer patients were randomly assigned to receive either 18 minutes of high MI CDUS during chemotherapy infusion (n = 6) or chemotherapy alone (n = 5). Tumor perfusion was measured before and after at least six chemotherapy cycles using motion-model ultrasound localization microscopy. Additionally, acute effects of CDUS on vessel perfusion and chemotherapy distribution were evaluated in mice bearing triple-negative breast cancer (TNBC).Results: Morphological and functional vascular characteristics of breast cancer in patients were not significantly influenced by high MI CDUS. However, complete clinical tumor response after neoadjuvant chemotherapy was lower in high MI CDUS-treated (1/6) compared to untreated patients (4/5) and size reduction of high MI CDUS treated tumors tended to be delayed at early chemotherapy cycles. In mice with TNBC high MI CDUS decreased the perfused tumor vessel fraction (p < 0.01) without affecting carboplatin accumulation or distribution. Higher vascular immaturity and lower stromal stabilization may explain the stronger vascular response in murine than human tumors.Conclusion: High MI CDUS had no detectable effect on breast cancer vascularization in patients. In mice, the same high MI CDUS setting did not affect chemotherapy accumulation although strong effects on the tumor vasculature were detected histologically. Thus, sonopermeabilization in human breast cancers might not be effective using high MI CDUS protocols and future applications may rather focus on low MI approaches triggering microbubble oscillations instead of destruction. Furthermore, our results show that there are profound differences in the response of mouse and human tumor vasculature to high MI CDUS, which need to be further explored and considered in clinical translation.

Contrast-enhanced ultrasound to visualize hemodynamic changes after rodent spinal cord injury.

OBJECTIVE Traumatic spinal cord injury (tSCI) causes an almost complete loss of blood flow at the site of injury (primary injury) as well as significant hypoperfusion in the penumbra of the injury. Hypoperfusion in the penumbra progresses after injury to the spinal cord and is likely to be a major contributor to progressive cell death of spinal cord tissue that was initially viable (secondary injury). Neuroprotective treatment strategies seek to limit secondary injury. Clinical monitoring of the temporal and spatial patterns of blood flow within the contused spinal cord is currently not feasible. The purpose of the current study was to determine whether ultrafast contrast-enhanced ultrasound (CEUS) Doppler allows for detection of local hemodynamic changes within an injured rodent spinal cord in real time. METHODS A novel ultrafast CEUS Doppler technique was developed utilizing a research ultrasound platform combined with a 15-MHz linear array transducer. Ultrafast plane-wave acquisitions enabled the separation of higher-velocity blood flow in macrocirculation from low-velocity flow within the microcirculation (tissue perfusion). An FDA-approved contrast agent (microbubbles) was used for visualization of local blood flow in real time. CEUS Doppler acquisition protocols were developed to characterize tissue perfusion both during contrast inflow and during the steady-state plateau. A compression injury of the thoracic spinal cord of adult rats was induced using iris forceps. RESULTS High-frequency ultrasound enabled visualization of spinal cord vessels such as anterior spinal arteries as well as central arteries (mean diameter [± SEM] 145.8 ± 10.0 µm; 76.2 ± 4.5 µm, respectively). In the intact spinal cord, ultrafast CEUS Doppler confirmed higher perfusion of the gray matter compared to white matter. Immediately after compression injury of the thoracic rodent spinal cord, spinal cord vessels were disrupted in an area of 1.93 ± 1.14 mm2. Ultrafast CEUS Doppler revealed a topographical map of local tissue hypoperfusion with remarkable spatial resolution. Critical loss of perfusion, defined as less than 40% perfusion compared to the surrounding spared tissue, was seen within an area of 2.21 ± 0.6 mm2. CONCLUSIONS In our current report, we introduce ultrafast CEUS Doppler for monitoring of spinal vascular structure and function in real time. Development and clinical implementation of this type of imaging could have a significant impact on the care of patients with tSCI.

Contrast enhanced ultrasound by real-time spatiotemporal filtering of ultrafast images

Contrast enhanced ultrasound (CEUS) takes advantage of the nonlinear behaviour of injected microbubbles. If these contrast techniques yield good specificity between bubbles and tissues, they suffer some drawbacks, inherently linked to their dependence on nonlinear content. In recent years, plane-wave ultrasound reached frame rates of up to 20 000 fps. In this study we propose a linear technique for CEUS that takes advantage of these very high frame rates to separate bubbles from tissue without requiring nonlinearities. Data-driven spatiotemporal filtering operations are used to separate different features in the image on the basis of coherence both in space and time. Such filter recently proved to improve Doppler sensitivity (Demene et al IEEE Trans. Med. Imaging 34 2271–85). In contrast with bubbles, even slow moving ones, tissues are highly coherent both in space and time. Therefore, singular value decomposition (SVD) seems to be a powerful tool for the separation of contrast agents and tissues. In this paper, we apply SVD processing to linear ultrafast ultrasound images for CEUS Doppler. The contrast levels reached by this technique were compared to those of a nonlinear gold standard sequence (PMPI Doppler) through a flow phantom study. The SVD technique reached contrast-to-tissue ratios (CTR) up to 10 dB higher in vitro, and proved to be robust in terms of probe motion and slow flow. A trial was also conducted on a transplanted human kidney, already imaged by means of power Doppler (Claudon et al Am. J. Roentgenol. 173 41–6) and microbubbles (Kay et al Clin. Radiol. 64 1081–7). Contrast levels yielded by the SVD technique measured up to 13 dB higher than those of PMPI Doppler.

Haemodynamic evaluation by Doppler ultrasonography in patients with portal hypertension: a review

Doppler ultrasonography (US) has an advantage of being non-invasive; therefore, several attempts have been made to investigate the haemodynamic alterations in cirrhosis and the response to medical treatment of portal hypertension. Doppler indices, which have been commonly used for the evaluation of portal hypertension, include the measurement of portal and splenic venous blood velocity and flows, and the resistive and pulsatility index at hepatic, splenic, renal, superior mesenteric artery. Although many positive evidences have been suggested, its clinical usefulness in portal hypertension remains unsettled because of being plagued by lack of reproducibility and accuracy characterized by intra- and interobserver variation. However, recently, Doppler's usefulness in assessment of severity of portal hypertension in terms of reproducibility, technical ease and accuracy and response to drugs that reduce the portal pressure has been proposed. In addition, because most of the patients with cirrhosis and portal hypertension have intrahepatic shunts, they show a decrease in intrahepatic circulatory time (IHCT). Doppler US using microbubble contrast agents allows measurement of IHCT. Therefore, application of contrast-enhanced Doppler US can be prospective for the assessment of the severity of portal hypertension. Several reports have demonstrated that colour Doppler endoscopic US enable haemodynamic study to assess the portal hypertension and has a role of guidance to measure the imaging-based variceal pressure. We have reviewed briefly the clinical usefulness of Doppler US in assessing the severity of portal hypertension and its response to treatment.

Contrast‐Enhanced Power and Color Doppler Ultrasonography of the Pancreas in Healthy and Diseased Cats

The diagnosis of feline pancreatic disease is difficult, because clinical abnormalities and routine noninvasive diagnostic tests are unreliable. The purpose of this study was to investigate by Doppler ultrasonography if vascularity and blood volume differs in the otherwise ultrasonographically normal and diseased feline pancreas. Thirty-six client owned cats. The pancreas was examined with B-mode and contrast-enhanced color and power Doppler ultrasonography. Doppler images were analyzed with a computer program: parameter fractional area represents a vascularity index and color-weighted fractional area assesses blood volume. Based on the B-mode findings, the pancreas was considered normal in 11 clinically healthy cats and diseased in 25 cats of which 4 were clinically healthy and 21 had clinical signs consistent with pancreatic disease. Histologic or cytologic samples were taken in all diseased pancreata. Fifteen samples were of diagnostic quality: purulent or mixed cellular inflammation (8), nodular hyperplasia (4), and neoplasia (3) were identified. Vascularity and blood volume for all Doppler methods was significantly higher in cats with pancreatic disease. Significantly higher Doppler values were detected with power Doppler than with color Doppler, and with postcontrast color and power Doppler than with precontrast Doppler technologies. Contrast-enhanced Doppler ultrasonography appears feasible in the feline pancreas. Significant differences were found between normal cats and those with evidence of pancreatic pathology. Further studies are needed to evaluate its use for the differentiation of pancreatic disorders and in cats suspected to have pancreatic disease but without B-mode ultrasonographic changes of the pancreas.

Gastrointestinal Stromal Tumors Treated with Imatinib: Monitoring Response with Contrast-Enhanced Sonography

The purpose of this study was to evaluate contrast-enhanced Doppler sonography with perfusion software as a predictor of early tumor response to imatinib (Glivec) in c-kit-positive gastrointestinal stromal tumors (GISTs). Thirty patients (59 tumors) with metastases or a recurrence from a GIST were prospectively included in a single-center imaging trial. Contrast-enhanced Doppler sonography was performed with an Aplio scanner the day before (day-1) starting oral treatment (400 mg) and at days 1, 7, 14, 60, 90, and 6 months, 9 months, and 1 year. The percentage of contrast uptake (Levovist or Sonovue) before treatment and at the different stages of follow-up was evaluated by two radiologists. Digitized quantification was performed using Photoshop software. To define the benchmark standard, all patients were rated as responders or nonresponders at 2 and 6 months by a board consisting of oncologists and radiologists who had all clinical and imaging data at their disposal. Changes in the percentage of contrast uptake at each sonographic examination were compared statistically. A total of 185 examinations were performed. Forty-four lesions in 24 patients were completely evaluated at 2 months, and 29 lesions in 15 patients were completely evaluated at 6 months. Initial contrast uptake at day 1 was predictive of the future response. A strong correlation was found between the decline in tumor contrast uptake at days 7 and 14 and tumor response (p < 10(-4)). Contrast-enhanced Doppler sonography is a noninvasive imaging technique that allows the early prediction of tumor response in c-kit-positive GIST treated with Glivec.

Contrast-enhanced Doppler Ultrasound for Guiding Percutaneous Microwave Ablation of Hepatocellular Carcinoma: A Report of 32 Cases

To evaluate the usefulness of contrast-enhanced Doppler ultrasound for percutaneous microwave ablation therapy (PMAT) of hepatocellular carcinoma (HCC). A total of 51 hepatic tumors in 32 patients with HCC were treated using a microwave system with a frequency of 2,450 MHz. Before and after PMAT, color Doppler imaging with a bolus injection of Levovist® (Schering AG, Berlin, Germany), at a dose 5 mL at 400 mg/mL, was performed with an A 128 XP10/ART unit (Acuson, Mountain View, CA), with a probe frequency of 3.5 MHz. Immediately after PMAT, gray-scale ultrasound imaging of the treated tumor appeared as a hyperechoic area with an acoustic shadow around the electrode. Non-contrast-enhanced color flow signals were detected in all 51 nodules before treatment, while color flow signals disappeared in 49 (96.1%) nodules and were still present in two nodules after the treatment. Contrast-enhanced sonography with Levovist® demonstrated only 36 nodules without flow signals and 15 nodules still having flow signals, 30 days after PMAT. Based on contrast-enhanced ultrasound findings, the residual tumor regions with blood flow signals were treated again within 1 month. Twenty-one of 32 patients had follow-up within 18 months (65.6%). Contrast-enhanced Doppler ultrasound is useful for evaluating ultrasound-guided PMAT for HCC.

Evaluation of the Effect of Protamine on Human Prostate Carcinoma PC-3m Using Contrast Enhanced Doppler Ultrasound.

We evaluated the ability of contrast enhanced Doppler ultrasound (CEDU) to demonstrate changes in tumor vascularity during angiogenesis inhibitive therapy in PC-3m human prostate carcinoma. Pieces of human prostate carcinoma PC-3m tumor (Institute of Urology, Beijing University, Beijing, People's Republic of China) were transplanted subcutaneously into 48 male BALB/C nude mice (Center of Animal Quarantine, Beijing, People's Republic of China). Protamine (Shanghai Biochemistry Pharmaceutical Co., People's Republic of China) was injected subcutaneously as an angiogenesis inhibitor. The animals were randomly divided into 3 groups according to protamine dose. The color flow signal-pixel rate (SPR) of the images was calculated using the number of pixels showing color Doppler signals as a ratio of the total number of pixels covering the lesion. The SPR of the high and low dose groups were significantly lower than that of the control group (p <0.01). Mean SPR +/- SD in the 3 groups was 0.09 +/- 0.05, 0.11 +/- 0.05 and 0.22 +/- 0.10, respectively. SPR correlated significantly with microvessel density (r = 0.86 to 0.94, p <0.01). CEDU can effectively reveal the change in vascularity in a tumor that was treated with protamine. In addition to microvessel density, CEDU may become one of several independent prognostic indexes of angiogenesis inhibitor therapy.

Evaluation of the effect of protamine on human prostate carcinoma PC-3m using contrast-enhanced Doppler ultrasound

ABSTRACTPurpose: We evaluated the ability of contrast enhanced Doppler ultrasound (CEDU) to demonstrate changes in tumor vascularity during angiogenesis inhibitive therapy in PC-3m human prostate carcinoma.Materials and Methods: Pieces of human prostate carcinoma PC-3m tumor (Institute of Urology, Beijing University, Beijing, People’s Republic of China) were transplanted subcutaneously into 48 male BALB/C nude mice (Center of Animal Quarantine, Beijing, People’s Republic of China). Protamine (Shanghai Biochemistry Pharmaceutical Co., People’s Republic of China) was injected subcutaneously as an angiogenesis inhibitor. The animals were randomly divided into 3 groups according to protamine dose. The color flow signal-pixel rate (SPR) of the images was calculated using the number of pixels showing color Doppler signals as a ratio of the total number of pixels covering the lesion.Results: The SPR of the high and low dose groups were significantly lower than that of the control group (p <0.01). Mean SPR ± SD i...

Enhanced sonography of the urinary tract

In the evaluation of the urinary tract, ultrasound contrast agents (USCAs) have been shown to be useful. USCAs do not have any renal toxicity. In the screening of renovascular hypertension, contrast-enhanced Doppler sonography improves the detection of main and supernumerary renal arteries, and reduces the frequency of technical failures. Using first-generation USCAs, the detection of renal cortical perfusion was achieved through the destruction of the bubbles to maximize the backscattered signals, requiring intermittent imaging to allow refilling of capillaries. Now, continuous non-destructive imaging has become possible with more recent agents using low and very low mechanical index values. The diagnosis of perfusion defects (i.e., renal infarct, pyelonephritis) is facilitated when the baseline Doppler signal is insufficient. USCAs improve detection of intratumoral blood flow and may be useful for characterization and/or detection of small, cystic, or nondetermined lesions at baseline US. As microbubbles remain strictly inside vessels, they can be viewed as blood pool markers, enabling functional imaging of the kidney. Bolus and infusion techniques are the two modalities of administration of the USCAs. Resulting time-intensity curves allow to approach renal blood flow and regional blood volume, and to provide additional information on perfusion disorders. Cystosonography has proven to be highly sensitive in the detection and grading of vesico-ureteral reflux in children.

Intravenous contrast-enhanced Doppler sonography and intra-arterial carbon dioxide-enhanced sonography in the assessment of hepatocellular carcinoma vascularity before and after treatment

To compare i.v. contrast-enhanced sonography (CEUS), power Doppler sonography (PDUS) and i.a. carbon dioxide-enhanced sonography (CO2US) in assessing hepatocellular carcinoma (HCC) vascularities before and after treatment. Differences between PDUS and CEUS with the aid of CO2US were also observed. In all, 43 patients with 67 histologically proved HCCs were examined with PDUS, CEUS, and CO2US. Among these tumors, 36 were HCCs before treatment and 31 were HCCs treated by transcatheter arterial chemoembolization or percutaneous ethanol injection or a combination of these two treatments. CO2US was used as the gold standard when comparing the PDUS and CEUS. Of the 36 untreated HCC tumors, 20 (55.6%) were hypervascular compared with the liver parenchyma at PDUS, 28 (77.8%) at CEUS, 31 (86.1%) at the early phase of CO2US and 32 (88.9%) at the late phase of CO2US. Of the 31 post-treatment HCCs, 11 (35.5%) showed hypervascularity at PDUS, 25 (80.6%) at CEUS, 25 (80.6%) at the early phase of CO2US and 26 (83.9%) at the late phase of CO2US. CO2US was superior to CEUS and CEUS was superior to PDUS for the detection of tumor vascularity in both untreated and treated HCCs. The duration of enhancement at CEUS was shorter than at CO2US. The ability of CO2US to detect additional small tumors was not possible with PDUS and CEUS.

Contrast-enhanced doppler ultrasonography in the diagnosis of hepatocellular carcinoma and premalignant lesions in patients with cirrhosis

Contrast-enhanced doppler ultrasonography in the diagnosis of hepatocellular carcinoma and premalignant lesions in patients with cirrhosis

Contrast-enhanced doppler ultrasonography in the diagnosis of hepatocellular carcinoma and premalignant lesions in patients with cirrhosis

Hepatocellular carcinogenesis in cirrhosis is a multistage process that includes large regenerative nodules, dysplastic nodules, and hepatocarcinoma. The aim of this study was to establish whether contrast-enhanced Doppler ultrasonography (US) is able to distinguish between early hepatocellular carcinoma (HCC) and small nonmalignant nodules in cirrhosis. Between January 1998 and December 1999, 500 cirrhotic patients with no previous history of HCC or evidence of hepatic focal lesions were enrolled and prospectively followed-up with US every 6 months until December 2000. Sixty-one patients developed focal lesions, 12 multifocal, and 49 monofocal. Biopsy of focal lesions, contrast-enhanced Doppler US, and spiral computed tomography (CT) were performed in 41 consecutive patients with small ([lt ]3 cm) monofocal lesions. Twenty nodules were diagnosed as HCC and 21 as nonmalignant (14 large regenerative nodules, 3 low-grade, and 4 high-grade dysplastic nodules) by liver biopsy. Intratumoral arterial blood flow was detected in 19 of 20 (95%) HCC and 6 of 21 (28%) nonmalignant nodules by contrast-enhanced Doppler US (P[lt ].0001). The mean peak resistance and pulsatility indices were 0.82 [plusmn] 0.09 and 1.56 [plusmn] 0.2 in HCC and 0.62 [plusmn] 0.08 and 0.82 [plusmn] 0.08 in dysplastic lesions (P = .002 and .0001), respectively. Spiral CT revealed arterial perfusion in 19 of 20 HCC and in 4 of 21 nonmalignant nodules (high-grade dysplastic nodules). Four of the apparently false-positive nodules at enhanced Doppler US were high-grade dysplastic nodules and 2 evolved to HCC during follow-up. In conclusion, contrast-enhanced Doppler US is a noninvasive, very sensitive technique in differentiating malignant and premalignant lesions from nonmalignant focal lesions in the liver. (HEPATOLOGY 2001;34:1109-1112.)

Localized gallbladder carcinoma: sonographic findings.

Our study of color (seven cases) and contrast (three cases) Doppler results of seven cases with gallbladder carcinoma localized in the gallbladder wall (TNM stage T1) showed that the presence or absence of blood flow signals distinguishes gallbladder carcinoma in stage T1b (muscular involvement) from tumefactive biliary sludge and that injection of contrast medium markedly increased diagnostic confidence. Thus, when color Doppler sonography is ambiguous, contrast-enhanced Doppler sonography is the next line of investigation. However, actual color Doppler sonography is still not fully capable of displaying fine blood flow signals from gallbladder carcinoma in stage T1a (mucosal involvement), and greater Doppler sensitivity is mandatory for this purpose.

Hepatocellular carcinoma and non malignant lesions in cirrhotic liver: assessment with contrast-enhanced doppler ultrasonography

Hepatocellular carcinoma and non malignant lesions in cirrhotic liver: assessment with contrast-enhanced doppler ultrasonography

Assessment of the vascularization of neuroendocrine tumors by stimulated acoustic emission of SH U 508A ultrasound contrast agent and color or power Doppler sonography.

To assess the vascularization of neuroendocrine tumors by stimulated acoustic emission (SAE) of SH U 508A during the blood pool phase in comparison with contrast-enhanced Doppler sonography. Thirty-six patients with neuroendocrine tumors received contrast-enhanced Doppler sonography and 21, an additional SAE. To classify tumor perfusion on Doppler sonography, a 4-step rating score was introduced: (1) no vessels (hypoperfusion); (2) one feeding or central vessel (hypoperfusion); (3) some vessels (hyperperfusion); and (4) disseminated vessels (hyperperfusion). In 36 patients, 1 pancreatic primary tumor, 33 liver metastases, 1 splenic metastasis, and 1 lymph node metastasis were examined. Results were correlated with biphasic spiral CT (n = 35) and angiography (n = 2). Arterial-phase CT and digital subtraction angiography revealed 18 hyper- and 18 hypoperfused lesions. Contrast-enhanced Doppler correctly classified 15 of 18 patients (83%) with hyperperfused lesions as well as 16 of 18 (89%) hypoperfused tumors by applying the rating score. SAE correctly identified 4 of 9 hyperperfused lesions (44%), 2 were isoperfused compared with normal liver tissue (22%), and 3 were hypoperfused (33%). Of 12 hypoperfused lesions, 11 were classified correctly (92%), and 1 showed isoperfusion. Hence, the positive and negative predictive values for SAE were 80% and 69%, respectively. For contrast-enhanced Doppler sonography, positive and negative predictive values were 88% and 84%, respectively. Blood pool SAE failed to determine subtle tumor perfusion correctly. The rating score for contrast-enhanced Doppler sonography characterized tumor perfusion with high accuracy. The use of a contrast agent significantly improved perfusion characterization.

Measurement of Cerebral Circulation Time by Contrast-Enhanced Doppler Sonography

We present a new, non-invasive ultrasound method for the measurement of cerebral circulation time. After injection of a galactose-based echo-contrast agent (Levovist) into an antecubital vein, cerebral circulation time is measured as the interval between the beginning of a stable signal enhancement of at least 5 dB in the internal carotid artery and in the ipsilateral internal jugular vein. Both vessels are insonated simultaneously at the mandibular angle using a single 2-MHz range-gated transducer. For this study, 25 healthy volunteers ranging in age from 23 to 55 years (30.1 ± 7.5 years; mean ± SD) were examined. Cerebral circulation time was 5.6 ± 1.7 s without significant side-to-side or sex-related differences. Measurement of circulation times offers a new possibility for the employment of echo-contrast agents in functional ultrasound.

Hepatocellular carcinoma treated with chemoembolization: assessment with contrast-enhanced doppler ultrasonography.

To report our preliminary experience concerning the use of Doppler ultrasonography (DUS) techniques after intravenous injection of the galactose-based contrast agent Levovist in the assessment of hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization (TACE). The sonographic findings are correlated with those obtained using iodized oil (Lipiodol) helical computed tomography (CT). For 7 months we studied 28 patients with cirrhosis and HCC (a total of 43 nodules) who had undergone TACE between 18 and 30 days previously. The lesions were investigated with color Doppler ultrasonography (CDUS) and power Doppler ultrasonography (PDUS), before and after infusion of the echo-contrast agent (300 mg/ml, maximum 1 injection for each nodule, administered at constant velocity within 60-90 sec), and with helical Lipiodol-CT (0-7 days after DUS). In the retrospective analysis, special attention was given to the Doppler signals related to pulsatile intra- and perinodular flow and to the detection of new vessels after contrast agent injection. The signal intensity was graded as 0 (absent), 1 (low), 2 (medium), or 3 (high), while its distribution was classified as peripheral, central, or diffuse. Oily agent retention on CT scans was assessed as 0 (absent), I (<10%), II (<50%), III (>50%), or IV (homogeneous). These scores were awarded separately, without knowledge of the other judgments. An hepatic global echo-enhancing effect was identified in all cases and always lasted long enough to allow an accurate analysis of all parenchymal lesions (at least 8 min). The signal scores could be evaluated in 39 of 43 HCCs, as follows: basal CDUS: grade 0 in 17 lesions, grade 1 in 16, grade 2 in 6; contrast-enhanced CDUS: grade 0 in 12 lesions, grade 1 in 10, grade 2 in 14, grade 3 in 3; basal PDUS: grade 0 in 15 lesions, grade 1 in 13, grade 2 in 9, grade 3 in 2; contrast-enhanced PDUS: grade 0 in 11 lesions, grade 1 in 9, grade 2 in 15, grade 3 in 6. Lipiodol-CT scoring was: grade 0 in 1 lesion, grade I in 7, grade II in 11, grade III in 9, grade IV in 11. In all but one nodule the difference between CDUS and PDUS scores, compared both with each other and with nonenhanced and contrast-enhanced examinations, was never greater than one grade. Contrast-enhanced DUS is a simple and fast procedure allowing a valuable, constant echo-enhancing effect of sufficient duration. DUS techniques, especially contrast-enhanced PDUS, offer an effective and realistic analysis of HCC nodules treated with TACE and show more evident agreement with Lipiodol-CT findings than baseline studies.

Contrast-Enhanced Doppler Ultrasound of Renal Artery Stenosis: Prologue to a Promising Future.

Over the past few years, there has been extensive research for a reliable, noninvasive, and nonionizing imaging method to screen for renal artery stenosis (RAS). Doppler ultrasound (US) is one of many modalities that have been evaluated for the detection of RAS. The lack of standardization in examination protocols and diagnostic criteria, as well as the wide differences in reported accuracy among different laboratories, however, have prevented universal acceptance of this technique as a reliable screening test for RAS. Recently, the introduction of US contrast agents has substantially expanded the potentials of color Doppler US. The use of microbubble echo enhancers 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. In addition, contrast-enhanced harmonic Doppler US can currently provide objective functional assessment of RAS through analysis of time-intensity renal enhancement curve. State-of-the-art contrast-enhanced Doppler US seems to have the potential to become a useful screening test for patients at risk from renovascular hypertension and a tool for follow-up of patients who undergo revascularization procedures.

Assessment of vascularity in reactive lymph nodes by means of D-galactose contrast-enhanced Doppler sonography.

A prospective study in signal-enhanced Doppler sonography of lymph nodes that were assumed pretherapeutically to be benign was performed to investigate characteristic sonomorphologic features and vascularity of reactively enlarged lymph nodes. Thirty-four patients with enlarged superficial lymph nodes of the neck were examined first by B-scan sonography then by Doppler sonography before and after administration of an ultrasound signal-enhancing agent. In B-scan sonography, lymph nodes were classified into three groups according to their sonomorphologic features: (1) homogeneous parenchyma, (2) a centrally located echogenoic line, and (3) a echogenoic "hilus reflex." In conventional and contrast-enhanced Doppler sonography, peak flow rate, pulsatility index, and resistive index were assessed. Sonomorphologic criteria were compared with histologic findings. Reactively enlarged lymph nodes showed characteristic sonomorphologic patterns correlating to their histologic features. Echogenicity of the hilus corresponded to fibrosis (centrally located echogenoic line in 13 nodes; 38.2%) or fatty involution of the hili (echogenoic hilus reflex in 15 nodes; 44.1%). Administration of the galactose-based ultrasound contrast enhancer facilitated the assessment of hilar vessels, which projected to the echogenoic hili, respectively, actually additionally visualized a hilar vascularity in 10 of the 34 lymph nodes compared with conventional Doppler. Measured Doppler indices gave not a significant clue for identifying reactive lymph nodes or for differential diagnosis. Qualitative sonomorphologic assessment of characteristic sonomorphologic features of reactive lymph nodes may serve as a valuable tool for examining reactively enlarged lymph nodes. Administration of an ultrasound echo enhancer allows the assessment of a characteristic nodal vascularity in reactive lymph nodes and were superior to conventional B-mode and conventional Doppler sonography.