Clinical utility of color Doppler sonography in the differentiation of hepatocellular carcinoma from metastases and hemangioma

Superb Microvascular Imaging: Added Value and Novel Applications

Determining the presence and characteristics of vascular flow is an essential part of sonography interrogation. However, small vessels and low velocities are not always possible to depict with conventional color and power Doppler ultrasound. This can be frustrating, especially when the diagnosis depends mainly on the existence of vascular flow, the sonographic examination will be inconclusive, further imaging examinations will be required and diagnosis delayed. Superb microvascular imaging (SMI) is a novel vascular imaging mode, which provides visualization of low velocity and microvascular flow. SMI uses a clutter suppression algorithm to extract flow signals and depicts this information as a color overlay image or as a monochrome or color map of flow. By using SMI, high frame rates and high-resolution images remain maintained. With SMI, it is possible to visualize small vessels including their branches that, until now, it is possible to demonstrate only using contrast-enhanced ultrasound. Availability of this additional technology on all ultrasound machines may make some of the computed tomography scans unnecessary. In our paper, we describe six patients, aged 16-73 years, in which final diagnosis was achieved only with SMI and where conventional color and power Doppler failed. All these examinations were performed using Aplio 500 Platinum ultrasound unit (Toshiba Medical Systems, Tokyo, Japan).

Characterization of liver lesions by real-time contrast-enhanced ultrasonography

OBJECTIVE

The aim of this study was to identify the most common patterns of various common liver lesions at real-time contrast-enhanced ultrasonography with second-generation contrast agents and their role in the differentiation of malignant from benign lesions.

PATIENTS AND METHODS

The enhancement pattern in the arterial phase and its modifications in subsequent portal and sinusoidal phases were separately evaluated in (i) 171 liver lesions detected at conventional ultrasonography in 125 noncirrhotic patients (87 metastases, six cholangiocellular carcinoma, 38 focal nodular hyperplasia, 30 hemangiomas, seven focal fatty sparing/changes, two hepatocellular adenomas and one hepatocellular carcinoma) and (ii) 75 lesions detected in 67 cirrhotic patients (66 hepatocellular carcinoma and nine dysplastic nodules). The final diagnosis was made by contrast-enhanced helical computed tomography and/or magnetic resonance imaging or by ultrasonography-guided biopsy when the diagnosis was equivocal at conventional imaging techniques (45 lesions).

RESULTS

In noncirrhotic patients, the hypoechoic pattern in portal and sinusoidal phase (rapid washout) or the markedly hypoechoic or anechoic pattern in sinusoidal phase (marked late washout) showed a sensitivity, specificity and accuracy of 96.8, 100 and 98.2% for the diagnosis of malignancy. In cirrhotic patients, early arterial enhancement showed a sensitivity of 93.9% for the diagnosis of malignancy, with a specificity as low as 55.5% given the presence of arterial enhancement in 5/9 nodules resulted dysplastic at histological analysis.

CONCLUSION

Real-time contrast-enhanced ultrasonography provides sensitive and specific criteria for the differential diagnosis between benign and malignant liver lesions, and in most cases it may replace more expensive and invasive imaging techniques.

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

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

Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US

BACKGROUND

We describe the spectrum of contrast-enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US).

METHODS

Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma.

RESULTS

After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and one showed a rim of peripheral enhancement, followed by progressive centripetal fill-in, which was complete in 10 of 14 cases and incomplete in four. Three of 18 hemangiomas showed rapid and complete fill-in in the arterial phase. Eight of eight focal nodular hyperplasias became hyperechoic in comparison with adjacent liver parenchyma in the arterial phase and slightly hyperechoic or isoechoic in the portal venous and delayed phases. Both adenomas showed strong arterial contrast enhancement that became less intense in the portal venous and delayed phases.

CONCLUSION

Contrast-enhanced US after administration of SonoVue enables depiction of typical contrast-enhancement patterns in most benign hepatic tumors arising in fatty liver, thus providing useful clues for characterization.

Usefulness of contrast-enhanced perfusional sonography in the assessment of hepatocellular carcinoma hypervascular at spiral computed tomography

BACKGROUND/AIMS

Diagnosis of hepatocellular carcinoma (HCC) relies strongly on the detection of hypervascularity in the arterial phase and, in this setting, spiral computed tomography (CT) is the most widely used method. This prospective study aimed to investigate the usefulness of low mechanical index harmonic ultrasound (US), using a second generation contrast-enhanced technique, in the assessment of vascular pattern of HCC shown to be hypervascular at spiral CT.

METHODS

A total of 79 cirrhotic patients with 103 nodules (mean+/-SD 28+/-13 mm) with arterial hypervascularity at spiral CT were studied. US examination was performed by perfusional sonography, using a new dedicated technology (CnTI-Esaote trade mark ), operating at low mechanical index, after injection of a second generation contrast agent (SonoVue trade mark -Bracco), allowing detection of tumoral flow during arterial phase.

RESULTS

Selective arterial enhancement on perfusional sonography was observed in 94 /103 nodules (91.3%), with a sensitivity of 66.6, 87.5, 91.7, and 97.3% in nodules </=1 cm, >1</=2 cm, >2</=3 cm, and >3 cm respectively.

CONCLUSIONS

Perfusional sonography shows good diagnostic agreement with spiral CT in hypervascular HCC and may be proposed for the immediate vascular characterization of nodules detected at US and used as second imaging technique to confirm hypervascularity in cirrhotic nodules.

Flash-echo gray-scale imaging in the subtraction mode for assessing perfusion of small hepatocellular carcinoma

PURPOSE

The aim of this study was to evaluate the effectiveness of using flash-echo imaging (FEI) in the subtraction mode to assess the vascularity of small hepatocellular carcinomas (HCCs) that had been unsatisfactorily assessed with power Doppler sonography.

METHODS

Between May 2000 and April 2001, we prospectively assessed nodular small HCCs using FEI in the subtraction mode after power Doppler sonography resulted in unsatisfactory images. After microbubble contrast was injected, we used the FEI technique to assess tumor perfusion in the arterial, portal, and delayed phases.

RESULTS

Our study population comprised 14 patients (10 men and 4 women) whose ages ranged from 31 to 79 years (mean, 61 +/- 13.7 years) and whose tumors ranged in size from 0.8 to 3 cm (mean, 1.8 +/- 0.5 cm). Power Doppler sonography was unable to assess tumor vascularity in 6 cases because of interference by heart pulsation, and it failed to detect a color signal in the other 8 cases. All tumors were enhanced with FEI. In the arterial phase, 7 of the 14 tumors (50%) showed hyperperfusion relative to liver parenchyma enhancement, 5 of 14 (36%) showed isoperfusion, and 2 of 14 (14%) showed hypoperfusion. In the portal phase, 3 of the 14 tumors (21%) showed isoperfusion, and the other 11 (79%) showed hypoperfusion. In the delayed phase, all 14 tumors showed hypoperfusion.

CONCLUSIONS

Despite heart pulsation and slow vascular flow, FEI in the subtraction mode was sensitive and effective in assessing the perfusion of small HCCs.

Color Doppler sonography of bile duct tumor thrombi in hepatocellular carcinoma

OBJECTIVE

To determine with the use of color Doppler sonography whether bile duct tumor thrombi had detectable vasculature in hepatocellular carcinoma.

METHODS

Among 491 patients with tissue-proven hepatocellular carcinoma, 9 (1.8%) had bile duct tumor thrombi. All 9 patients had spectral Doppler sonography guided by color Doppler sonography (3.75-MHz convex probe).

RESULTS

All 9 patients had dilated bile ducts with isoechoic thrombi. Eight patients had tumors infiltrating into and obstructing adjacent major bile ducts. The other patient had common hepatic duct tumor emboli that were not adjacent to primary tumors. Color signals were detectable within bile duct tumor thrombi in 7 patients. All of them had pulsatile waveforms on spectral analyses.

CONCLUSIONS

Bile duct tumor thrombosis with obstructive jaundice was a rare complication of hepatocellular carcinoma. A detectable color signal with pulsatile waveforms was shown in most cases by color Doppler sonography with spectral analyses.

Assessment of vascular patterns of small liver mass lesions: value and limitation of the different Doppler ultrasound modalities

OBJECTIVES

This study aimed to investigate the value and limitation of the different Doppler ultrasound modalities (spectral analysis, color, and power Doppler imaging) in the differential diagnosis of small liver tumors to identify the optimal diagnostic approach with the presently available Doppler technology.

METHODS

Presence and distribution of color and power Doppler signals, Doppler peak frequency, resistive index, and systolic acceleration time were examined in 133 liver nodules (< or = 4 cm).

RESULTS

Color and power Doppler did not identify specific diagnostic vascular patterns. By discriminant analysis, peak frequency (cut-off 1320 Hz) differentiates small hematocellular carcinoma (< or = 2 cm) from macroregenerative nodules and hemangiomas (accuracy 92.6%); resistive index (cut-off 0.65) differentiates malignancies from benign lesions (accuracy 83.8%); and systolic acceleration time (cut-off 105 ms) differentiates hepatocellular carcinoma from metastases (accuracy 80.9%).

CONCLUSIONS

Power Doppler imaging is able to assess vascularity in the majority of small liver nodules, but the pattern distribution of tumoral vascular signals does not provide reliable differential diagnostic criteria. Using conventional Doppler technology, power Doppler should be used to detect vascular signals and spectral analysis, and subsequently to measure quantitative parameters such as high peak frequency and resistive index (which identify malignancy) and prolonged systolic acceleration time (which identifies primary from metastatic liver tumors).

Percutaneous ethanol injection of the supplying artery to hepatocellular carcinoma that is not amenable to conventional treatment

The purpose of this study was to evaluate the clinical usefulness of ultrasound-guided percutaneous ethanol injection of the supplying artery (PEISA) to the tumour in the palliative management of hepatocellular carcinoma (HCC) that is not amenable to conventional treatments. A total of 23 cases of HCC, measuring from 3.1 cm to larger than 15 cm (median 5.4 cm) in 17 cirrhotic patients, were treated by PEISA. PEISA was used to control rapid growth of the tumour in seven patients and to reduce abdominal discomfort caused by rapid expansion of the tumour in 10 patients. Tumours with arterial Doppler signals persisting after PEISA underwent repeated treatment. The follow-up period ranged from 2-48 months. PEISA was achieved in 69 out of 76 attempts (90.8%). The amount of ethanol injected on each occasion ranged from 2.5-33 ml. Follow-up colour Doppler scanning showed complete elimination of tumour Doppler signals in 22 out of 23 lesions (95.7%). Following treatment, one tumour disappeared, 13 tumours shrank and nine tumours were unchanged in size. All patients with abdominal discomfort had relief after treatment. The common complications of PEISA were local pain and fever. In conclusion, PEISA is effective at treating painful HCC unsuitable for conventional treatment.

Clinical evaluation of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors

PURPOSE

We investigated the value of contrast-enhanced color Doppler sonography in the differential diagnosis of liver tumors.

METHODS

We prospectively examined 105 focal liver lesions in 100 patients by real-time gray-scale sonography, color Doppler sonography, and contrast-enhanced color Doppler sonography with galactose-based microbubbles (SH U 508A; Levovist). The final diagnoses of the liver lesions as confirmed by pathology or additional imaging techniques were 31 metastases, 25 hemangiomas, 19 hepatocellular carcinomas, 19 focal nodular hyperplasias, 2 cholangiocellular carcinomas, and 9 other lesions.

RESULTS

Vascularity could be detected in 43 (41%) of the 105 lesions by conventional color Doppler sonography compared to 67 (64%) by contrast-enhanced color Doppler sonography. Contrast-enhanced color Doppler sonography identified moderate or extensive vascularity in all 19 focal nodular hyperplasias, moderate or extensive vascularity in 16 hepatocellular carcinomas and both cholangiocellular carcinomas, and no or minor vascularity in all but 3 hemangioma. The combination of gray-scale, conventional color Doppler, and contrast-enhanced color Doppler sonography led to the correct diagnosis in 81% of cases (85 of 105), compared to 57% (60/105) for gray-scale and conventional color Doppler sonography and 31% (33/105) for gray-scale sonography alone.

CONCLUSIONS

Contrast-enhanced color Doppler sonography improves the detection of tumor vascularity and is useful in the differential diagnosis of liver lesions.

Monitoring response to treatment in liver tumours

New imaging techniques offer better ways of measuring response to treatment and remain central to the formal assessment of response in clinical trials and routine clinical practice. Increasing tumour size is consistently associated with progressive disease. However, there is evidence that the designation 'partial response', as determined by conventional imaging techniques, may not always accurately reflect the degree of treatment-induced tumour necrosis. Thus, responses classified as partial on imaging grounds have, in some cases, been shown to be complete pathological responses after surgical resection, implying that residual tumour and necrotic/fibrotic tumour remnants cannot always be accurately distinguished by imaging. In this situation, serological tumour markers such as alphafetoprotein may be useful in measuring the true degree of response. While radiological imaging is likely to remain the main method of assessing response in phase II trials of drugs for the treatment of liver cancer, it may in some instances be useful to apply additional parameters such as alphafetoprotein level.

Doppler sonography of the native liver

Doppler sonography is being used routinely in evaluating the vascular structures of the native liver because of its ease of use, lower cost, easier availability, lack of need for X-ray and accuracy. Doppler sonography can well demonstrate the vascularization of liver tumors, portal vein thrombosis, portal vein abnormalities in patients with portal hypertension and hepatic venous findings in patients with Budd Chiari syndrome. The purpose of this article is to present information about Doppler sonography of the native liver and to show its usefulness in the evaluation of hepatic vascular diseases.

Contrast-enhanced power Doppler sonography: improved detection of characteristic flow patterns in focal liver lesions

PURPOSE

The aim of this study was to evaluate whether intravenous injection of an ultrasound contrast agent aids in the visualization of focal liver lesions on power Doppler images.

METHODS

Fifty patients with focal liver lesions were studied by B-mode and power Doppler sonography before and after intravenous injection of the contrast agent Levovist (galactose-based microbubbles; 10 ml of a concentration of 300 mg/ml). Thirty-two patients had malignant liver lesions (19 metastases, 12 hepatocellular carcinomas, 1 cholangiocellular carcinoma), while 18 had benign lesions (12 hemangiomas, 2 focal nodular hyperplasias, 4 others).

RESULTS

After contrast medium injection, the number of lesions with no intralesional flow dropped from 18 to 9. Flow signal intensity was rated subjectively as marked on contrast-enhanced images in 17 patients; only 4 patients had marked flow on precontrast images. On precontrast studies, central flow in 10 lesions and peripheral flow in 29 lesions could be observed. After enhancement, the numbers increased to 18 and 34 lesions, respectively.

CONCLUSIONS

On power Doppler images, a greater number of intratumoral vessels are seen in focal liver lesions after contrast medium administration.

Duplex Doppler sonography of small (<3 cm diameter) liver tumours: intralesional arterial flow does not exclude cavernous haemangioma

In small liver lesions (<3 cm diameter), detection of internal arterial flow with duplex Doppler sonography is thought to virtually exclude the diagnosis of cavernous haemangioma. We retrospectively reviewed 114 consecutive small lesions confirmed or suspected to be haemangiomas. Doppler sonography revealed intralesional arterial flow in four lesions for which correlative imaging studies were diagnostic of haemangioma, and for which stability was documented with follow-up sonography. We conclude that intralesional arterial flow should not be interpreted as conclusive evidence that a small liver lesion is not a haemangioma. If the presence of arterial flow within a small liver lesion prompts concern that the lesion is not a haemangioma, our findings suggest that a correlative imaging study should be considered before percutaneous biopsy is performed.

Hepatic imaging. An overview

Recent advances in ultrasound, CT scan, MR imaging, and scintigraphy permit characterization of a variety of focal and diffuse liver diseases. Accurate clinical information, however, is of vital importance in selecting the optimal imaging modality and interpreting the study accurately. Using a combination of radiologic findings and clinical information, a correct diagnosis may be achieved noninvasively.