Hepatocellular carcinoma: power Doppler US with a contrast agent--preliminary results

Contrast-enhanced ultrasonography using levovist: Usefulness of diagnosis of small focal nodular hyperplasia lesions

Differential diagnosis of focal nodular hyperplasia and hepatocellular carcinoma is clinically important because, while both are hypervascular tumors, they have vastly different prognoses. Because the spoke-wheel appearance is the primary characteristic of focal nodular hyperplasia, we attempted to detect this pattern in nodules smaller than 3 cm in diameter with contrast-enhanced ultrasonography using a contrast agent (Levovist). Four patients were examined with contrast-enhanced US: two of the patients were examined with Coded Harmonic Angio; the other two patients were examined with contrast-enhanced color and power Doppler US without harmonic imaging. Although the hepatic arteriogram showed the spoke-wheel appearance in only one tumor (diameter, 3 cm), contrast-enhanced US clearly demonstrated this characteristic in all four tumors, including three tumors that were less than 2 cm in diameter. Because it is noninvasive and can be carried out in an outpatient clinic, contrast-enhanced US is extremely useful for diagnosing small focal noduler hyperplasia lesions at sites that can be observed with US.

Power Doppler ultrasonography for the assessment of vascular invasion by pancreatic cancer

AIM

To investigate the diagnostic accuracy of power Doppler ultrasonography (US) in assessing the vascular invasion by pancreatic cancer.

METHODS

A prospective study of 40 consecutive patients with pancreatic cancer (head 35, body 5) was performed. All patients underwent surgery. The relationships between tumor and each vessel were classified into four types according to the closest circumferential contact of the tumor with the vessel. A type 0 indicated no contact; type 1 indicated less than one third contact; type 2 indicated one third to 99% contact, and type 3 indicated encasement. Vascular invasion was diagnosed in types 2 and 3. The diagnostic accuracy was evaluated in the portal vein and in the splanchnic arteries (celiac artery, common hepatic artery, and superior mesenteric artery). The power Doppler US findings were confirmed by the operative findings. The results of power Doppler US were compared with those of CT scan and angiography.

RESULTS

Portal vein invasion was confirmed in resected specimens in 23 cases and by operative findings in 5 cases. For the diagnosis of portal vein invasion, sensitivity, specificity, and overall accuracy of power Doppler US were, respectively, 79.3, 90.9, and 82.5%. The respective values were 79.3, 100, and 85% for CT and 72.4, 81.8, and 75% for angiography. For the diagnosis of arterial invasion, sensitivity, specificity, and overall accuracy of power Doppler US were 80, 92, and 90%, respectively. The corresponding values were 47, 88, and 73% for CT and 47, 100, and 80% for angiography.

CONCLUSION

Power Doppler US proved to be useful for the diagnosis of vascular invasion by pancreatic cancer.

A straightforward algorithm for the quantification of power Doppler signals

RATIONALE AND OBJECTIVES

To document a simple algorithm that quantifies power Doppler signals by computer-based statistical image analysis.

METHODS

Personal computer-based software was developed. Color pixels representing power Doppler signals were separated from the background gray pixels in power Doppler images converted in BMP format. To avoid misregistration during this segmentation, a threshold value is required to adequately distinguish between gray and color pixels. Equating the intensity of each color pixel to a Power Value (PV), a histogram of Power Values in power Doppler images was obtained.

RESULTS

The software was designed to allow users to adjust two thresholds (Difference Threshold and Intensity Threshold) by observing the segmentation results in real time. The software calculates the following indexes within any region of interest as defined by the operator: mean PV, peak PV, standard deviation of PV, percentage power Doppler area, and integrated PV per unit area.

CONCLUSIONS

Power Doppler signals can be objectively quantified using this straightforward algorithm. This simple and practical method can be applied to comparative or longitudinal studies upon vascularity or blood flow.

Dynamic sonography of pancreatic tumors: comparison with dynamic CT

OBJECTIVE

The aim of this study was to examine the usefulness of dynamic sonography in the characterization of pancreatic tumors.

MATERIALS AND METHODS

IV contrast-enhanced pancreatic sonography (dynamic sonography) with Levovist was performed in 43 patients with pancreatic mass lesions (32 with pancreatic adenocarcinomas, four with inflammatory pancreatic masses, three with islet cell tumors, two with serous cystadenomas, one with a solid and cystic tumor, and one with metastatic pancreatic cancer). We calculated a contrast index using a time-intensity curve: contrast index equals elevation of intensity in the tumor divided by elevation of intensity in the pancreatic parenchyma. We classified the tumors into three groups according to the contrast index: a slightly enhanced group (contrast index < 0.5), a moderately enhanced group (contrast index = 0.5-1.5), and a well-enhanced group (contrast index > 1.5), and we compared these results with those from dynamic CT.

RESULTS

The contrast indexes of 32 adenocarcinomas, four inflammatory pancreatic masses, three islet cell tumors, two serous cystadenomas, one solid and cystic tumor, and one metastatic tumor were, respectively, 0.12 +/- 0.095 (mean +/- SD), 0.54 +/- 0.420, 1.74 +/- 0.555, 1.09 +/- 1.380, 1.67, and 2.07. Thirty-five tumors, including all 32 adenocarcinomas, were classified in the slightly enhanced group, three were classified in the moderately enhanced group, and five were classified in the well-enhanced group. In 93% (40/43) of tumors, the grade of enhancement on dynamic sonography was closely correlated with the grade of enhancement on dynamic CT.

CONCLUSION

Dynamic sonography can assist in the characterization of pancreatic tumors.

Ultrasonic assessment of the peri- and postmenopausal ovary

OBJECTIVE

To analyze the role of B-mode ultrasound, color and power Doppler examination and three-dimensional ultrasound with and without power Doppler facilities in evaluation of the peri- and postmenopausal ovaries.

METHODS

Review of the literature on ultrasonic assessment of the ovaries in postmenopausal patients.

RESULTS

Ultrasound has assumed an increasing role in the evaluation of the peri- and postmenopausal ovaries. Ovarian lesions are a cause of great concern because of their malignant potential and the limited ability to distinguish accurately between benign and malignant lesions using morphological sonographic criteria alone. Superimposed color Doppler imaging enables the visualization of vascularization and blood flow characteristics of the ovaries and/or ovarian lesions. It becomes possible to detect normal, suspicious and pathologic blood flow characteristics even in small blood vessels. Owing to superb quality of the images, three-dimensional sonography enables precise assessment of the ovarian lesions. Three-dimensional power Doppler ultrasound permits effective targeting and rendering of ovarian tumor vasculature, thus providing new diagnostic possibilities for early detection of ovarian malignancy and differentiation of benign from malignant ovarian pathology.

CONCLUSIONS

Further technological development will contribute to more objective evaluation of ovarian tumor morphology and vasculature which will give us tremendous support in clinical decision making and planning the management.

Which continuous US scanning mode is optimal for the detection of vascularity in liver lesions when enhanced with a second generation contrast agent?

OBJECTIVES

Microbubble echo-enhancers help in the assessment of focal liver masses by enhancing the signal from blood vessels. A variety of linear and nonlinear scanning modes are now available, but it is unclear which is optimal. A controlled comparison was performed during the infusion of such an agent (SonoVue: Bracco, Milan, Italy).

METHODS AND MATERIALS

Ten patients with known focal liver lesions were studied. The diagnoses, confirmed on dual phase helical computed tomography (CT) at the same attendance were metastasis (n = 7), haemangioma (n = 2) and focal nodular hyperplasia FNH (n = 1). A dose of 12 ml SonoVue concentrated at 5 mg/ml was infused intravenously at a rate of 1 ml/min. The enhancement level was monitored with a continuous wave (CW) Doppler probe over the right radial artery and the intensity of the signal was registered at 1 s intervals. When a plateau of enhancement was reached, a single lesion in each patient was imaged using five different continuous scanning modes, fundamental grey scale (FGS); fundamental colour Doppler (FCD); fundamental power Doppler (FPD); second harmonic grey scale (HGS); and pulse inversion mode (Pim) using an HDI5000 scanner and C5-2 probe (ATL, Bothell, WA). The order of scanning modes was varied between patients using a predefined randomisation protocol. The videos (super video home system (SVHS)) were analysed offsite by two blinded readers, both experienced in contrast ultrasound of the liver. The readers were asked to score each mode in terms of its ability to detect vessels within/around the lesion at optimal enhancement. This was done using a ranking system (1, worst; 5, best) for each patient.

RESULTS

Both observers scored FPD as the optimal imaging method, followed by Pim. (Scores summed across all patients, observer 1: FPD 48, Pim 42, FCD 37, HGS 21, FGS 10; observer 2: FPD 49, Pim 40, FCD 38, HGS 21, FGS 10). The differences from FPD were significant for FCD, HGS and FGS using a unpaired analysis of variance (ANOVA) comparison, with Bonferroni multiple corrections, (P<0.01, both observers). The differences between FPD and Pim were also significant both for observer 2 and for both observers combined (P<0.01), but did not reach significance for observer 1 (P = 0.19).

CONCLUSIONS

In this study, FPD performed best, and the non-linear modes, performed continuously (pulse inversion and second HGS), showed no clear advantage.

Enhancement of hepatic hemangiomas with levovist on coded harmonic angiographic ultrasonography

OBJECTIVE

To evaluate the pattern of contrast enhancement with Levovist on coded harmonic angiographic ultrasonography of hepatic hemangiomas.

METHODS

Twenty hemangiomas were evaluated with coded harmonic angiographic ultrasonography and a microbubble contrast agent. Verification of the diagnosis of a hemangioma was made by means of dynamic computed tomography (n = 8), dynamic magnetic resonance imaging (n = 1), radionuclide scanning (n = 6), or follow-up ultrasonography (n = 5). Ultrasonographic images were obtained before contrast agent administration and with a bolus injection of 2.5 g of a microbubble contrast agent (300 mg/mL Levovist; Schering AG, Berlin, Germany) every 10 to 15 seconds for 5 minutes. The contrast enhancement patterns of the 20 hemangiomas were assessed.

RESULTS

The tumor diameters as measured on ultrasonography were 7 to 97 mm (mean, 26.7 mm). Of the 20 hemangiomas, peripheral globular enhancement with progressive centripetal fill-in was shown in 15 (75%), rimlike enhancement with progressive centripetal fill-in was shown in 2 (10%), and homogeneous enhancement was shown in 1 (5%). In the remaining 2 lesions (10%), the enhancement patterns could not be seen, because they were not found on coded harmonic angiographic ultrasonography.

CONCLUSIONS

Coded harmonic angiographic ultrasonography with a microbubble contrast agent can depict the typical enhancement pattern in most hepatic hemangiomas.

Hepatocellular carcinoma: contrast enhancement with Levovist

OBJECTIVE

To present the sonographic appearance of hepatocellular carcinoma imaged with the intravenous contrast agent Levovist.

METHODS

We reviewed our experience using Levovist (Schering AG, Berlin, Germany) for the sonographic diagnosis of hepatocellular carcinoma.

RESULTS

Contrast-enhanced sonography with Levovist facilitated detailed evaluation of tumor vascularity in hepatocellular carcinoma.

CONCLUSIONS

Contrast-enhanced sonography with Levovist enhances the role of sonography in the diagnosis of hepatocellular carcinoma. It provides detailed information about tumor vascularity and the contrast enhancement pattern.

Evaluation of posttreatment response of hepatocellular carcinoma with contrast-enhanced coded phase-inversion harmonic US: comparison with dynamic CT

PURPOSE

To assess the reliability of contrast material-enhanced real-time gray-scale ultrasonography (US) in evaluating posttreatment response of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Fifty HCC nodules were examined with contrast-enhanced coded phase-inversion harmonic US before and after treatment. Intratumoral vascularity was assessed with continuous imaging in the early arterial phase and with interval-delay scanning to depict tumor parenchymal flow during the blood pool phase. Vascular findings at US were compared with those at dynamic computed tomography (CT).

RESULTS

In 50 HCC nodules before treatment, positive enhancement of tumor vessels and tumor parenchymal flow (stain) were observed in 47 (94%) and 46 (92%), respectively. Either tumor vessel or stain was visualized with coded harmonic US in 49 of 50 nodules. Eighty-one coded harmonic US studies were performed in 49 posttreatment HCC nodules. Compared with dynamic CT, the sensitivity, specificity, and accuracy of coded harmonic US in helping to detect positive enhancement in pretreatment HCC were 98% (49 of 50), 100% (50 of 50), and 98% (49 of 50), respectively. After treatment, positive enhancement of tumor vascularity was observed in 39 (48%) of 81 posttreatment studies, and no enhancement was observed in others (52%). Coded harmonic US demonstrated partial and no enhancement of tumor vascularity in four and one nodule, respectively; after transcatheter arterial embolization with iodized oil, evaluation of tumor vascularity with dynamic CT was difficult because of the presence of oil.

CONCLUSION

With enhancement, coded harmonic US depicted tumor vascularity by showing tumor vessels in a real-time fashion at continuous imaging and tumor parenchymal flow at interval-delay scanning.

Dynamic sonography of hepatic tumors

OBJECTIVE

Our objectives were to propose and evaluate a dynamic sonography protocol for the characterization of hepatic tumors.

SUBJECTS AND METHODS

The subjects were 107 patients with focal liver lesions that initially had been found on conventional sonograms. The final diagnoses for the lesions were hepatocellular carcinoma in 60 patients, cholangiocellular carcinoma in six, metastatic carcinoma in 24, hemangioma in 10, and focal fat-spared region in seven. The pulse inversion harmonic imaging mode and a galactose-based contrast agent (Levovist) were used. Dynamic sonography was designed to obtain vascular-phase (composed of the arterial phase and the portal phase) images of the focal lesion and liver-parenchymal-phase images of the whole liver in a series obtained after a bolus injection of the contrast agent.

RESULTS

If the whole-tumor or mosaic enhancement patterns (arterial phase) and/or the reticular enhancement (parenchymal phase) are regarded as positive findings for hepatocellular carcinoma, the sensitivity, specificity, and positive predictive value of dynamic sonography in our study were 92%, 96%, and 96%, respectively. If a ring enhancement (arterial to portal phase) or a clear defect (parenchymal phase) or both are regarded as positive findings for cholangiocellular carcinoma or metastasis, the sensitivity, specificity, and positive predictive value were 90%, 95%, and 88%, respectively. If puddle enhancement (portal phase) is regarded as a positive finding for hemangioma, the figures for sensitivity, specificity, and positive predictive value were 60%, 100%, and 100%, respectively. Also, the tumors that showed no focal sign in the liver parenchymal phase were all benign lesions, such as hemangiomas or focal fat-spared regions.

CONCLUSION

Dynamic sonography in a protocol combining pulse inversion harmonic imaging and an IV bolus injection of the contrast agent proved to be an effective tool in characterizing liver tumors.

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.

Hepatocellular carcinoma: depiction of tumor parenchymal flow with intermittent harmonic power Doppler US during the early arterial phase in dual-display mode

PURPOSE

To assess the effectiveness of contrast material-enhanced intermittent harmonic Doppler ultrasonography (US) in depicting tumor vessels and tumor parenchymal flow (stain) in hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Fifty-eight patients with 65 HCC nodules were examined by using intermittent harmonic power Doppler US and digital subtraction harmonic B-mode US, both with intravenous administration of SH U 508A. Vascular findings at early arterial phase harmonic US were classified as positive enhancement or nonenhancement, depending on the tumor vascularity relative to the surrounding liver parenchyma. These results were compared with those of three-phase helical dynamic computed tomography (CT).

RESULTS

For hypervascular HCCs, there was excellent depiction of tumor vessels and tumor stain with the two intermittent harmonic US methods. The sensitivity and specificity for depiction of tumor vascularity were 93% (41 of 44 nodules) and 100% (21 of 21), respectively, with intermittent harmonic power Doppler US and 86% (38 of 44) and 100% (21 of 21), respectively, with subtraction US, as compared with these values at dynamic CT. Attenuation was an important factor in the depictability of tumor vascularity at harmonic US.

CONCLUSION

Contrast-enhanced intermittent harmonic US enables noninvasive demonstration of tumor vessels and especially tumor stain in HCC.

Percutaneous ablation of liver malignancies: imaging evaluation of treatment response

Interventional procedures for percutaneous tumor ablation have gained an increasingly important role in the treatment of liver malignancies. After interventional therapies, diagnostic imaging has the key role to determine if the treated lesion is completely ablated or contains areas of residual viable neoplastic tissue. This is particularly important since in cases of incomplete necrosis of the lesions, treatment can be repeated, and tumor ablation can be further pursued. The evaluation of the therapeutic effect of the procedure arises different problems according to the histotype of the malignancy. In the case of hepatocellular carcinoma (HCC), detection of residual viable tumor is facilitated by the typical hypervascular pattern of this neoplasm. Contrast-enhanced US can be used to monitor tumor response, and, in cases of partial necrosis, to target the areas of residual viable tumor. With spiral CT or dynamic MR imaging, residual viable HCC is reliably depicted as it stands out in the arterial phase images against the unenhanced areas of coagulation necrosis. In the case of hypovascular metastases, a confident diagnosis of successfull ablation can be made when an area of thermal necrosis exceeding that of the original lesion is depicted. Peripheral inflammatory reaction following ablation procedures, that shows itself as an enhancing halo along the necrotic area boundary on spiral CT or dynamic MR images, should not be misinterpreted as tumor progression.

Ultrasound contrast agents: a promising future

The emerging field of contrast ultrasound has great and untapped potential. Improved vascular enhancement may increase the number and type of diagnostic vascular examinations. Improved vessel depiction may increase examination speed and improve patient throughput. New gray-scale contrast imaging techniques may substantially increase the sonographic detection and characterization of liver, kidney, and other focal parenchymal masses. Contrast ultrasound examinations may increase diagnostic confidence, decrease nondiagnostic studies, and decrease the requirement for additional imaging studies. Further investigation is needed, however, to determine the diagnostic use and cost-effectiveness of this new approach relative to CT, MR imaging, angiography, and conventional ultrasound imaging.

Pancreas: imaging diagnosis with color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography

Recent advances of ultrasound imaging have made possible to depict various diseases and conditions of the pancreas. Color/power Doppler ultrasonography, endoscopic ultrasonography, and intraductal ultrasonography are feasible to show vascular abnormalities, differentiate the solid and cystic tumors, decide tumor extent, and help to perform interventional treatments of the pancreatic diseases. Those techniques will contribute to the more precise and easier diagnosis and to prompt decision of the treatments of the pancreatic disorders. Radiologists should recognize the diagnostic feasibility and limitations of those techniques in order to avoid unnecessary examinations on the patients, and obtain precise diagnostic images.

Quantified power Doppler US of tumor blood flow correlates with microscopic quantification of tumor blood vessels

PURPOSE

To evaluate the ability of a quantified power Doppler ultrasonography (US) system to help quantitate differences in tumor vascularity after radiation therapy and administration of tumor necrosis factor (TNF).

MATERIALS AND METHODS

Murine glioblastoma tumors were grown in the thighs of two sets of 25 mice each. Each mouse was assigned to one of four treatment groups: control (no treatment), radiation therapy, TNF therapy, or combination therapy (both radiation and TNF therapies). Mice were then evaluated with quantified power Doppler US, and a vascularity index (color area) was calculated for different tumor regions in each group. The tumors were then excised, and histologic evaluation was performed by using an immunofluorescence-tagged monoclonal antibody against blood vessel endothelium. The number of stained blood vessels per high-power field was correlated with the sonographically determined vascularity index.

RESULTS

The color area of the total tumor decreased to 37% of that in the control group in mice treated with radiation therapy alone (P: =.02), 26% of that in the control group in mice treated with TNF alone (P: =.05), and 8% of that in the control group in those treated with both TNF and radiation (P: =.006). These results correlated well with the quantified results from immunofluorescent staining (r = 0.98).

CONCLUSION

Quantified power Doppler US is a noninvasive method for the evaluation of tumor vascularity and blood flow.

Contrast-enhanced subtraction harmonic sonography for evaluating treatment response in patients with hepatocellular carcinoma

OBJECTIVE

Our objective was to assess the usefulness of contrast-enhanced subtraction harmonic sonography in evaluating the treatment response of patients with hepatocellular carcinoma.

SUBJECTS AND METHODS

Thirty-two hepatocellular carcinoma lesions in 26 patients (age range, 44-85 years; mean age, 66 years) were examined with Levovist-enhanced intermittent harmonic imaging before and after therapy. A Toshiba Powervision 8000 was used. A subtraction image was obtained by digitally subtracting the last-frame harmonic image from the first-frame image when multishot mode was preset. Results of contrast-enhanced CT were compared with the results of subtraction harmonic imaging.

RESULTS

Before therapy, an enhancement pattern of tumor vascularity was seen for 93.8% (30/32) of hepatocellular carcinoma nodules on subtraction harmonic imaging. After therapy, subtraction harmonic imaging showed 46.7% (14/30) enhancement (incomplete tumor necrosis) and 53.3% (16/30) no enhancement (complete tumor necrosis). When dynamic CT was the gold standard, the sensitivity, specificity, and accuracy of subtraction harmonic imaging were 93.3%, 100%, and 96.7%, respectively. Intratumoral flow signals in hepatocellular carcinoma after therapy on harmonic imaging were used as a guide to target additional percutaneous therapy.

CONCLUSION

Digital subtraction contrast-enhanced harmonic imaging can depict tumor vascularity in hepatocellular carcinoma after therapy sensitively and accurately. Because it is easy to perform and provides real-time needle insertion guidance, it may be preferable to perform after localized therapy to monitor treatment response, which will reduce unnecessary CT scanning.

Radiologic diagnosis of hepatocellular carcinoma

Substantial recent technologic improvements in CT scanning, US scanning, and MR imaging, together with advances in the understanding of the optimal application of contrast administration techniques, have facilitated advances in radiologic imaging detection for HCC diagnosis. Despite a large number of earlier publications reporting a high sensitivity for imaging detection of HCC, more recent screening studies of large cirrhotic populations confirm that only 37% to 45% of HCC tumor nodules are detected by CT scanning, US scanning, or MR imaging. Future investigation will include efforts to improve the detection of small tumors and to characterize with greater specificity the spectrum of nodular changes that occur with cirrhosis. Although several small series have attempted to characterize cirrhotic nodules by evaluating the relative arterial or portal blood supply, these preliminary results require substantiation with larger series. Continued technologic advances such as multidetector helical CT scanning and new US and MR contrast agents under investigation may improve the imaging characterization of cirrhotic nodules.

Visualization of blood flow in hepatic vessels and hepatocellular carcinoma using B-flow sonography

PURPOSE

A B-flow sonographic technique was recently developed to provide direct visualization of blood flow with gray-scale sonography. Compared with color Doppler sonography, B-flow imaging has wideband resolution and a high frame rate. The purpose of this study was to evaluate the usefulness of B-flow sonography for visualizing blood flow in hepatic vessels and tumor vascularity in patients with liver cirrhosis or hepatocellular carcinoma (HCC).

METHODS

Twenty-five patients with liver cirrhosis, including 15 with HCC, were studied by B-flow and color Doppler sonography. Blood-flow detection rates in portal veins and hepatic arteries and tumor vascularity in HCC were analyzed, and the 2 methods were compared.

RESULTS

Using B-flow, blood flow was visualized in the portal vein in 23 (92%) of 25 patients and was visualized in the hepatic artery separately from the portal vein in 9 (36%) of 25 patients. The blood-flow signals were visualized only within vessels, never "bleeding" outside the vessel's lumen. Blood flow in the portal vein was observed with color Doppler sonography in all 25 patients, but the hepatic artery was never clearly separated from the portal vein. Vascularity within the HCC tumor was detected in 9 (60%) of 15 nodules with B-flow imaging, and fine arteries flowing into the tumor were observed in 6 nodules. Color Doppler sonography detected blood flow in 13 (87%) of the 15 HCC nodules.

CONCLUSIONS

Blood flow in hepatic vessels and tumor vessels of HCC were visualized with B-flow sonography. B-flow sonography is a potentially useful technique for the evaluation of liver vascularity and intratumoral vessels.

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.

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.

Assessment of arterial tumor vascularity in small hepatocellular carcinoma. Comparison between color doppler ultrasonography and radiographic imagings with contrast medium: dynamic CT, angiography, and CT hepatic arteriography

Hepatocellular carcinoma (HCC) is characterized by tumor vascularization from the hepatic artery. The objective of our work was to compare color Doppler ultrasonography (CDU), including power Doppler ultrasonography (PDU) with radiographic imagings with contrast medium in regard to the detection of the arterial tumor vascularity of small hepatocellular carcinomas (HCC). We examined 42 small HCC lesions 2 cm or less in diameter in 37 patients for arterial tumor vascularity by conventional CDU, PDU, dynamic computed tomography (dCT), digital subtraction angiography (DSA), and CT hepatic arteriography (CTA). Color images were detected in 25 (59.5%) and 28 (66.7%) of the 42 lesions with conventional CDU and PDU, respectively, and tumor vascularity was detected in 26 (61.9%) by dCT, 23 (54.8%) by DSA, and 29 (69.0%) by CTA. Tumor vascularity could be detected in 51.9% by PDU and CTA, more than by conventional CDU, dCT, and DSA (44.4, 44.4, and 33.3%, respectively) in well-differentiated HCC, whereas the detection rates by these techniques were almost equal (86.7% by CDU, 93.3% by PDU, dCT, and DSA, 100% by CTA, respectively) in moderately and poorly differentiated HCC. PDU is superior to CDU, dCT and DSA and equal to CTA for the detection of tumor vascularity in small HCC, particularly in well-differentiated HCC.

Hepatic tumors: contrast agent-enhancement patterns with pulse-inversion harmonic US

PURPOSE

To evaluate contrast agent-enhancement patterns in hepatic hemangiomas, hepatic metastases, and hepatocellular carcinomas (HCCs) at pulse-inversion harmonic ultrasonography (US) with a microbubble contrast agent.

MATERIALS AND METHODS

Twenty hepatic hemangiomas in 20 patients and 41 malignant hepatic tumors in 23 patients (33 metastases and eight HCCs) were evaluated with pulse-inversion harmonic US. US images were obtained before injection and every 10-15 seconds after injection of a 4-g bolus (300 mg/mL) of SH U 508A (a microbubble contrast agent) for 5 minutes. The contrast-enhancement patterns of 61 hepatic lesions were assessed.

RESULTS

Of 20 hemangiomas, 19 revealed peripheral enhancement, which was globular in 14 (70%) and rimlike in five (25%), with centripetal fill-in; the remaining one (5%) showed homogeneous enhancement. In 33 metastases, the enhancement was rimlike in 16 (48%), homogeneous in seven (21%), and stippled in two (6%); in the remaining eight metastases (24%), no enhancement was seen. Of eight HCCs, four (50%) showed homogeneous enhancement and the remaining four (50%) showed heterogeneous enhancement. Centripetal fill-in of lesions with intratumoral enhancement was not seen in any malignancy.

CONCLUSION

Pulse-inversion harmonic US with a microbubble contrast agent is potentially useful for the specific diagnosis of hemangiomas that demonstrate characteristic enhancement features.

Improved characterisation of focal liver tumours: dynamic power Doppler imaging using NC100100 echo-enhancer

OBJECTIVE

To assess the vascularisation of focal hepatic tumours using NC100100, enhanced power Doppler imaging.

METHODS

Twenty-two patients with focal liver tumours (12 metastases and ten hemangiomas) were studied. Using standardised settings, power Doppler imaging with ATL HDI3000 was performed before and after intravenous administration of NC100100 contrast agent. The video-recorded examinations were digitised for off-line analysis on a personal computer. Regions of interest were defined over the entire tumour and a neighbouring area of the normal liver parenchyma. The temporal changes of the mean power Doppler signal intensity (PDSI) was quantified to provide contrast agent wash-in (PDSI-time) curves for the initial 40 s.

RESULTS

Liver metastases were characterised by a rapid increase in PDSI, while the PDSI-time curves within hemangiomas were flat. The PDSI within the tumour increased significantly in ten subjects with liver metastases and only one subject with hemangioma. An enhanced rim around hemangiomas was seen in four subjects. There was no clear relationship between the contrast agent dose and the peak PDSI within metastases.

CONCLUSIONS

Power Doppler imaging with NC100100 contrast agent enhances tumour visualisation and may aid differential diagnosis of focal liver lesions.

Hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is increasing in many countries as a result of an increase in hepatitis C virus (HCV) infection since World War II. The epidemiology of HCC varies with the global region. There have been conflicting observations from different parts of the world concerning the frequency of HCC in patients who in the distant past had post-transfusion non-A, non-B hepatitis. The genetic basis of hepatocarcinogenesis is still poorly understood. In hepatitis B virus (HVB) associated HCC, codon 249 mutation in the p 53 gene seems more related to exposure to aflatoxin B1 than to hepatocarcinogenesis itself. HCC that occurs in children in high HBV endemic regions could be associated with germ-line mutations, but little information is available; not much is known about chemical hepatocarcinogens in the environment other than aflatoxins. The X gene of HBV seems to play an important role in HBV-associated hepatocarcinogenesis. There are preliminary observations on the molecular mechanism of HCV-associated HCC, such as HCV core protein inducing HCC in transgenic mice and the NS3 genome transforming NIH 3T3 cells. Pathological distinction between preneoplastic and very early transformed lesions still depends on classical morphology, and a more genetically oriented differential diagnosis is required. Clinical diagnosis based on modern imaging has improved greatly, but is still unsatisfactory in the differential diagnosis of preneoplastic and early transformed nodules, because the vasculature changes that occur within the nodule are not accurately discerned with the current imaging. Use of sensitive des-gamma-carboxy prothrombin (PIVKA II) assay, and lectin affinity chromatography separating HCC specific subspecies of AFP molecules with a more practical biochemical technique will further improve diagnosis. Early diagnosis and transplantation are the best treatment at the moment, but transplantation is not widely available because of the donor shortage. Despite successful resection, the remnant cirrhotic liver frequently develops new HCC lesions, seriously curtailing long-term survival. All-out efforts should be directed to the prevention of HCC, through prevention of viral hepatitis, prevention of acute hepatitis from becoming chronic, prevention of chronic hepatitis from progressing to cirrhosis, and prevention of the cirrhotic liver from developing HCC (chemoprevention). At the moment, very few such studies exist.

Harmonic hepatic US with microbubble contrast agent: initial experience showing improved characterization of hemangioma, hepatocellular carcinoma, and metastasis

PURPOSE

To characterize blood flow in focal hepatic lesions with harmonic ultrasonographic (US) imaging and a microbubble contrast agent.

MATERIALS AND METHODS

Thirty patients with known hepatic masses were examined after injection of a perfluorocarbon microbubble agent. Tumor vascularity was assessed with continuous, harmonic gray-scale imaging with a low mechanical index (MI). Tumor vascular volume was assessed with brief, high-MI insonation called interval-delay imaging, which caused microbubble destruction. As the total contrast agent volume in the liver reflects the total vascular volume, quantitation of lesion enhancement relative to normal hepatic enhancement helped determine the vascular volume of the tumor relative to that of normal parenchyma.

RESULTS

Low-MI continuous harmonic imaging showed lesional vessels in hepatocellular carcinomas, minimal or no vessels in hemangiomas, and variable vascularization in metastases. High-MI interval-delay imaging showed greater enhancement in hepatocellular carcinomas than in normal liver (P <.02) and showed less enhancement in hemangiomas than in normal liver (P <.02). Enhancement in metastases was greater in the margins than in the center; as a result, the lesions appeared smaller (P <.03) and less well defined on the interval-delay images.

CONCLUSION

Contrast-enhanced harmonic imaging appears superior to conventional Doppler US for hepatic mass characterization. Low-MI continuous and high-MI interval-delay imaging can help assess tumor vascular pattern and microvascular volume.

Power Doppler sonography: evaluation of hepatocellular carcinoma after treatment with transarterial embolization or percutaneous ethanol injection therapy

OBJECTIVE

The aim of this study was to compare tumor detectability by assessing the vascularity on power and color Doppler sonography and CT after transarterial embolization or percutaneous ethanol injection therapy or both in hepatocellular carcinoma.

SUBJECTS AND METHODS

Forty-seven nodules of hepatocellular carcinoma (size, 28 +/- 7 mm [mean +/- standard deviation]; range, 20-40 mm) in 38 patients were treated with transarterial embolization (n = 6), percutaneous ethanol injection therapy (n = 23), and transarterial embolization plus percutaneous ethanol injection therapy (n = 9). Power Doppler sonography, color Doppler sonography, and CT were performed before and 2 weeks, 3 months, and 6 months after the treatments. The existence of hepatocellular carcinoma was confirmed by positive findings for color signals on both Doppler sonography techniques and for tumor stains on CT. All the tumors were determined to be malignant by microscopic examination of biopsy specimens.

RESULTS

Before the treatments, power Doppler sonography (100%) and CT (100%) were significantly more effective than color Doppler sonography (61.7%) (p < 0.001, for both). Six months after the treatments, the sensitivity of power Doppler sonography (87.5%) was significantly better than that of color Doppler sonography (12.5%) but was not significant in comparison with CT (66.6%). However, power Doppler sonography detected color signals in two of three tumors in which iodized oil was accumulated and no tumor stain appeared on CT, and the two lesions detected with power Doppler sonography were carcinomas.

CONCLUSION

Power Doppler sonography can be considered the most sensitive technique in assessing the viability of hepatocellular carcinoma treated with transarterial embolization or percutaneous ethanol injection therapy or both.

Vascularity of hepatocellular carcinoma: assessment with contrast-enhanced second-harmonic versus conventional power Doppler US

PURPOSE

To compare contrast material-enhanced harmonic power Doppler ultrasonography (US) with conventional power Doppler US in depicting the vascularity of hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Twenty patients with nodular HCCs (2.6-13.2 cm in diameter; mean diameter, 4.8 cm) were prospectively examined with both conventional and harmonic power Doppler US. US was performed with a 2-4-MHz curved linear-array transducer according to a standard examination protocol (1,000-Hz pulse repetition frequency, medium wall filter, and power gain of 55%-84% for conventional power Doppler US; 700-Hz pulse repetition frequency, low wall filter, and power gain of 95%-98% for harmonic power Doppler US). Serial, dynamic scans were obtained before intravenous injection of the contrast agent (SH U 508A) and at 30, 60, 90, 120, 180, 240, and 300 seconds after injection with both techniques.

RESULTS

The number of intratumoral power Doppler US signals was similar with both techniques at 30-90 seconds after contrast agent injection; however, after 90 seconds, conventional power Doppler US depicted significantly more signals than did harmonic power Doppler US. Harmonic power Doppler US was superior to conventional power Doppler US in terms of power Doppler artifacts such as "blooming" or motion-related artifacts.

CONCLUSION

Although the effective enhancement duration is relatively short compared with that for conventional power Doppler US, contrast-enhanced harmonic power Doppler US can be effective in evaluating the vascularity of HCCs because of the advantage of fewer power Doppler artifacts.

[Intrahepatic transtumoral arteriovenous fistulae (diagnosis, importance, therapeutic proposals)]

The authors present the angiographic aspects of four patients having an arteriovenous transhepatic transtumoral fistula (two arterioportal and two arteriovenous). The angiographic results of the occlusion with cyanoacrylate (Hystoacryl) of the right hepatic artery in one and by the infusion of Lipiodol in two are also shown. The physiopathological characteristics of each kind of fistula are discussed and the consequences of the passage of the quimioembolizing mixture through the tumor, regarding intrahepatic abscess formation, irregular clinical results and pulmonary complications are commented. These complications make the diagnosis of a transtumoral transhepatic arteriovenous fistula, previously to the chemoembolic treatment important, even though being frequently difficult, because of the reduced caliber of the feeding artery and eventual low transfistular bloodflow. The efficient occlusion of the arterioportal fistula with Histoacryl was favourably compared to the infusion of Lipiodol, which was unable to occlude the arteriovenous fistula. The contraindication to perform chemoembolic treatment of hepatic tumors, when an intrahepatic transtumoral arteriovenous fistula is present and the embolization of the fistular feeding artery is stressed. Ultrasonography using color Doppler and sono-enhancing contrast is appointed as the ideal non-invasive means of making the diagnosis of an hepatic transtumoral fistula and makes it eligible to be the first test in the algorithm for the appraisal of hepatic tumors.

Hepatic hemangiomas: spectrum of US appearances on gray-scale, power Doppler, and contrast-enhanced US

Because US plays a key role in the initial evaluation of hepatic hemangiomas, knowledge of the entire spectrum of US appearances of these tumors is important. Most hemangiomas have a distinctive US appearance, and even with those with atypical appearances on conventional gray-scale US, specific diagnoses can be made using pulse-inversion harmonic US with contrast agents. In this essay, we review the spectrum of US appearances of hepatic hemangiomas on conventional gray-scale, power Doppler, and pulse-inversion harmonic US with contrast agents.

New approaches to the investigation of focal hepatic lesions

In the past few years, tremendous advances have been made in the fields of magnetic resonance imaging, computed tomography and ultrasonography. These include the development of novel contrast agents and new approaches to image acquisition and processing. This review provides an overview of the state-of-the-art of imaging investigation of focal hepatic lesions and highlights some of the most exciting emerging technologies.

Correlation between hepatic tumor index on color Doppler sonography and tumor vessels on arteriography in large hepatocellular carcinomas

We assessed a possible correlation between the hepatic tumor index (as the ratio of the tumoral peak systolic velocity to the peak systolic velocity of the right or left hepatic artery) and grade of tumor vessel in large hepatocellular carcinomas (HCCs). Color Doppler sonographic findings were evaluated and compared with selective hepatic arteriographic findings in 78 patients with 93 hepatocellular carcinomas larger than 2.0 cm in diameter. Pulsatile color flow images were obtained in 78 of 93 lesions. The hepatic tumor index was equal to or greater than 1.0 in 57 of 78 lesions. These lesions were revealed arteriographically to have distinct tumor vessels and/or arteriovenous shunting. When this index was 1.0 or greater, we calculated 90% accuracy in distinguishing HCCs with distinct tumor vessels from those without distinct tumor vessels. The hepatic tumor index correlated with the grade of tumor vessels and the presence of arteriovenous shunting.