Characterization of focal liver lesions with SonoVue®-enhanced sonography: International multicenter-study in comparison to CT and MRI

Changes of guidelines diagnosing hepatocellular carcinoma during the last ten-year period

Hepatocellular carcinoma (HCC) is the third most common cause of cancer deaths in the world. There have been many advances in the diagnosis of HCC during the last ten years, especially in the imaging techniques. The Korean Liver cancer study group (KLCSG), European Association for the Study of the Liver (EASL), American Association for the Study of Liver disease (AASLD), and Asian-Pacific Association for the Study of Liver (APASL) have made and changed the HCC guidelines with the advances in the imaging techniques and according to the results of the researches on HCC. We reviewed the changes of the imaging guidelines in HCC diagnosis according to the advances in the imaging techniques. Further studies will be necessary to resolve the controversies in the diagnosis of HCC smaller than 1 cm in size.

Hepatocellular adenoma: evaluation with contrast-enhanced ultrasound and MRI and correlation with pathologic and phenotypic classification in 26 lesions

Purpose. To review the contrast-enhanced ultrasonographic (CEUS) and magnetic resonance (MR) imaging findings in 25 patients with 26 hepatocellular adenomas (HCAs) and to compare imaging features with histopathologic results from resected specimen considering the new immunophenotypical classification. Material and Methods. Two abdominal radiologists reviewed retrospectively CEUS cineloops and MR images in 26 HCA. All pathological specimens were reviewed and classified into four subgroups (steatotic or HNF 1α mutated, inflammatory, atypical or β-catenin mutated, and unspecified). Inflammatory infiltrates were scored, steatosis, and telangiectasia semiquantitatively evaluated. Results. CEUS and MRI features are well correlated: among the 16 inflammatory HCA, 7/16 presented typical imaging features: hypersignal T2, strong arterial enhancement with a centripetal filling, persistent on delayed phase. 6 HCA were classified as steatotic with typical imaging features: a drop out signal, slight arterial enhancement, vanishing on late phase. Four HCA were classified as atypical with an HCC developed in one. Five lesions displayed important steatosis (>50%) without belonging to the HNF1α group. Conclusion. In half cases, inflammatory HCA have specific imaging features well correlated with the amount of telangiectasia and inflammatory infiltrates. An HCA with important amount of steatosis noticed on chemical shift images does not always belong to the HNF1α group.

[Ultrasound-guided image fusion with computed tomography and magnetic resonance imaging. Clinical utility for imaging and interventional diagnostics of hepatic lesions]

Abdominal ultrasound is often the first-line imaging modality for assessing focal liver lesions. Due to various new ultrasound techniques, such as image fusion, global positioning system (GPS) tracking and needle tracking guided biopsy, abdominal ultrasound now has great potential regarding detection, characterization and treatment of focal liver lesions. Furthermore, these new techniques will help to improve the clinical management of patients before and during interventional procedures. This article presents the principle and clinical impact of recently developed techniques in the field of ultrasound, e.g. image fusion, GPS tracking and needle tracking guided biopsy and discusses the results based on a feasibility study on 20 patients with focal hepatic lesions.

Current and potential renal applications of contrast-enhanced ultrasound

The combination of microbubble technology and complementary ultrasound techniques has resulted in the development of contrast-enhanced ultrasound (CEUS) and, although initial clinical applications largely focussed on the liver, these are now becoming more diverse. With regard to the kidney, it is a safe, well-tolerated, and reproducible technique, and in selected cases, can obviate the need for computed tomography or magnetic resonance imaging. A clear advantage is the absence of nephrotoxicity. With respect to the current and potential renal applications, it is a useful technique in the evaluation of pseudotumours, acute pyelonephritis, renal tumours, cystic lesions, vascular insults, and renal transplantation. It may also be of value for monitoring the kidney following anti-angiogenic treatment or nephron-sparing interventional techniques for renal tumours. Assessment of microvascular perfusion using time-intensity curves is also likely to have further far-reaching applications in the kidney as well as other organs.

[Summary of technical principles of contrast sonography and future perspectives]

Ultrasound contrast agents have considerably expanded the range of ultrasound diagnostics. Up to date ultrasound machines with contrast-specific software allow the selective demonstration and quantification of contrast agents in real-time based on the specific signal signature of oscillating contrast agent microbubbles. After intravenous injection the microbubbles are transported with the bloodstream and distributed purely intravascularly. This allows an artefact-free representation of the vascular architecture and delineation of the vascular lumen, independent of blood flow velocity and with high spatial resolution. Traumatic lesions and active bleeding can be detected with high sensitivity. Blood volume in vessels and organs can be assessed qualitatively and quantitatively. The possibility of short-term destruction of microbubbles within the ultrasound field allows the measurement of blood flow velocity during replenishment and based on that the assessment of perfusion in parenchymal tissue. Target-specific microbubbles for imaging of molecular surface structures as well as drug-loaded microbubbles for local ultrasound-mediated therapy are under development.

Acoustic Radiation Force Impulse (ARFI) ultrasound imaging of solid focal liver lesions

OBJECTIVE

The aim of this paper was to evaluate the application of ARFI ultrasound imaging and its potential value for characterizing focal solid liver lesions.

MATERIALS AND METHODS

In this multicentric prospective study, over a total non-consecutive period of four months, all patients underwent ARFI US examination. Two independent operators performed 5 measurements per each lesion and 2 measurements in the surrounding liver. According to the definitive diagnosis, a mean velocity value and standard deviations were obtained in each type of focal solid lesion, compared by using t-test, and the inter-operator evaluation was performed by using the Student's t-test. A comparison between the total mean values of each type of lesion and the mean value of the parenchyma was performed.

RESULTS

40 lesions were evaluated and a total of 400 measurements were obtained. The lesions were: 6/40(15%) hepatocellular carcinomas, 7/40(17.5%) hemangiomas, 5/40(12.5%) adenomas, 9/40(22.5%) metastases and 13/40(32.5%) focal nodular hyperplasias. The total mean values obtained were: 2.17 m/s in HCCs, 2.30 m/s in hemangiomas, 1.25 m/s in adenomas, 2.87 m/s in metastases and 2.75 m/s in FNHs. The inter-operator evaluation resulted non-statistically different (p>0.05). A significant difference (p<0.05) was always found by comparing adenomas to the other lesions. 160 measurements were obtained in the surrounding parenchyma, with a no significant difference between values measured in adenomas and in the surrounding liver.

CONCLUSIONS

ARFI technology with Virtual Touch tissue quantification could non-invasively provide significant complementary information regarding the tissue stiffness, useful for the differential diagnosis of focal solid liver lesions.

Contrast-enhanced ultrasound features of hepatocellular carcinoma of different sizes

AIM: To analyze the contrast-enhanced ultrasound (CEUS) features of hepatocellular carcinoma (HCC) of different sizes.

METHODS: A total of 75 consecutive patients with 90 HCC lesions were enrolled. HCC was examined by CEUS and confirmed by surgery and pathology. These patients were divided into two groups according to the maximum diameter of the lesion: small HCC (SHCC) group (diameter ≤3 cm) and large HCC (LHCC) group (>3 cm). The CEUS characteristics of HCC of different sizes were analyzed retrospectively.

RESULTS: Among 90 lesions, 39 were small HCC (SHCC) and 51 were large HCC (LHCC). During the arterial phase, all the 39 lesions in the SHCC group exhibited hyperenhancement, of which 37 (94.9%) were homogeneously and 2 (5.1%) were inhomogeneously enhanced. Comparatively, all the 51 lesions in the LHCC group exhibited hyperenhancement, of them 27 (52.9%) appeared as homogeneous enhancement, 21 (41.2%) as inhomogeneous enhancement and 6 (6%) as atypical patterns. The enhancement patterns had significant difference during the arterial phase between the two groups (P < 0.05). During the portal phase, 10 (25.6%) lesions were isoechoic and 29 (74.4%) were hypoechoic in the SHCC group, while 7 (13.7%) lesions were hyperechoic, 2 were isoechoic (3.9%), and 42 (82.4%) were hypoechoic in the LHCC group. A significant difference was also noted in enhancement patterns during the portal phase between the two groups (P < 0.05). During the late phase, hypoenhancement was visualized in all the SHCC lesions, while in the LHCC group, hypoenhancement was visualized in 50 (98%) lesions and isoenhancement in 1 (2%) lesion. No significant difference was observed in enhancement patterns during the late phase between the two groups.

CONCLUSION: Our study shows that the enhancement manifestations of HCC are related to lesion size. During the arterial phase, most SHCC lesions show homogeneous enhancement, while inhomogeneous enhancement patterns appear mostly in LHCC lesions. During the portal and late phases, SHCC lesions may be washed out earlier than LHCC ones.

Liver-test abnormalities in sarcoidosis

BACKGROUND

Sarcoidosis is a multisystemic inflammatory granulomatous disease. The prevalence of hepatic involvement is not clear.

AIM

The aim of this study was to establish the presence and severity of the liver-test abnormalities in sarcoidosis.

METHODS

Retrospectively, patients with confirmed sarcoidosis (n=837) presented with the liver-test abnormalities [alkaline phosphatase, γ-glutamyl transaminase, alanine aminotransferase or aspartate aminotransferase >1.5 times the upper limit of normal (ULN)] who were classified according to severity into mild (zero liver tests ≥3×ULN), moderate (one or two liver tests ≥3×ULN) and severe (three or four liver tests ≥3×ULN) were evaluated. Moreover, the relationship between severity of liver tests and histology was examined.

RESULTS

Liver-test abnormalities were found in 204 of 837 patients with chronic sarcoidosis (24.4%), among which 127 (15.2%) were suspected of having hepatic sarcoidosis (79 of 127 males, 111 Caucasian, eight African-American). In 22 of 127 patients (17.3%), a liver biopsy was obtained; 21 were compatible with hepatic sarcoidosis. In these 21 patients, severity of liver-test abnormalities was significantly associated with extensiveness of granulomatous inflammation (ρ=0.58, P=0.006) and degree of fibrosis (ρ=0.64, P=0.002). These results remained in the multiple regression analysis when controlled for treatment status, sex, genetics, ethnicity and age.

CONCLUSION

Liver-test abnormalities were present in 24% of the studied patients; in 15% highly because of hepatic involvement of sarcoidosis. Moderate and severe liver-test abnormalities seemed to be associated with more advanced histopathological disease. Therefore, in the management of sarcoidosis, for patients with moderate or severe liver-test abnormalities a liver biopsy is recommended.

Contrast-enhanced ultrasonography of peripheral soft-tissue tumors: Feasibility study and preliminary results

OBJECTIVES

To determine the diagnostic value of contrast-enhanced ultrasonography, to differentiate benign and malignant soft-tissue tumors and to assess the feasibility and interest of modelling enhancement curves.

PATIENTS AND METHODS

This retrospective study includes 118 patients with soft-tissue tumors, examined with ultrasound after injection of SonoVue(®), a contrast product. The raw data were treated with CHI-Q acquisition software to model the enhancement curves. We analyzed tumor uptake of the contrast product visually and studied the enhancement curves, characterized by five parameters: peak intensity, time to peak, mean transit time, initial slope, and area under the curve.

RESULTS

There were 81 benign and 37 malignant tumors. For a diagnosis of benign tumor, the absence of contrast uptake had a sensitivity of 60%, a specificity of 68%, a positive predictive value of 50% and a negative predictive of 83%. Study of the 70 curves obtained (48 benign and 22 malignant tumors) showed that the parameters of area under the curve (Chi(2)=8.6 and P<0.005), slope (Chi(2)=8.12 and P=0.004), and peak intensity (Chi(2)=7.55, P=0.005) differed significantly between the two populations.

CONCLUSION

Absence of contrast uptake suggests a benign lesion. The study of enhancement curves showed significant differences between the different tumor populations.

Characterisation of focal liver lesions with unenhanced and contrast enhanced low MI real time ultrasound: on-site unblinded versus off-site blinded reading

OBJECTIVE

To compare on-site and blinded off-site reading of baseline ultrasound (US) and contrast enhanced ultrasound (CEUS) for classification and characterisation of focal liver lesions.

MATERIALS AND METHODS

99 patients (57 women and 42 men, age range 18-89 years, mean age: 59 years) with 53 malignant and 46 benign liver lesions were studied with unenhanced US followed by contrast enhanced US after injection of 2.4 ml SonoVue® (Bracco, Milano, Italy). Image interpretation was performed on-site with clinical information available by consensus of two readers and off-site by two independent blinded readers at two different centers. Comparison of pre and post contrast scans and of the different readers was performed. Reference examinations were histology, intraoperative US, MRI or CT.

RESULTS

Sensitivity for malignancy improved from 81/89/66% (on-site/off-site reader 1/2) before to 100/96/96% post contrast administration (p<0.05, except for reader 1). Specificity improved from 48/48/54% on baseline US to 89/80/76% on CEUS (p<0.05). Accuracy for specific lesion diagnosis was 62/59/50% pre and 90/77/72% post contrast (p<0.05). Classification and characterisation post contrast were mildly inferior for off-site reading. Agreement between on-site and off-site readers of unenhanced scans was fair (κ=0.29-0.39) while it was good for CEUS (κ=0.63-0.79).

CONCLUSIONS

CEUS improves classification and characterisation of focal liver lesions and interobserver agreement compared to conventional US. Classification and characterisation post contrast were mildly but statistically significantly better for on-site than for off-site reading.

Contrast-enhanced ultrasound in oncology

In patients with known malignant disease, 51% of liver lesions less than 1.5 cm turn out to be benign. Whether the probability of malignancy is high or low, further investigations are often necessary to definitely exclude malignancy. Contrast-enhanced ultrasonography has a prominent role in lesion characterization with a diagnostic accuracy comparable with computed tomography and magnetic resonance imaging. Anti-angiogenic treatment is common in most oncological institutions and the response evaluation is a new challenge with a research focus on the change in tumour vasculature and perfusion. In planning biopsies, CEUS can identify necrotic and viable areas of tumours and improve the diagnostic accuracy.

Evaluation of focal hepatic lesions with ultrasound contrast agents

Ultrasound contrast agents have gained wide acceptance for the detection and characterization of focal liver lesions. This pictorial essay reviews the growing body of evidence that supports the use of modern ultrasound contrast agents and illustrates the enhancement characteristics of commonly encountered focal liver lesions. Pathologies discussed include metastases, hepatocellular carcinomas, focal nodular hyperplasia, hepatocellular adenomas, hemangiomas, abscesses, complex cysts, and focal fatty deposition.

Double contrast-enhanced ultrasonography for the preoperative evaluation of gastric cancer: a comparison to endoscopic ultrasonography with respect to histopathology

BACKGROUND

This study was designed to compare the accuracy of endoscopic ultrasound (EUS) with double contrast-enhanced ultrasound (DCUS) in the staging of gastric malignancies. DCUS is a transabdominal ultrasound technique using both intravenous and intraluminal contrast to enhance sonographic visualization.

METHODS

This retrospective study included 162 patients with biopsy-proven gastric cancer who underwent DCUS and EUS preoperatively with the ultrasound results compared with the pathologic findings of the resected specimens.

RESULTS

The overall accuracy of DCUS and EUS for tumor (T) staging was 77.2% and 74.7%, respectively. Comparison of ultrasound techniques for T staging revealed that DCUS was superior to EUS only for a tumor depth of T3 (chi-square, P = .025). Lymph nodes were staged correctly with DCUS and EUS in 78.4% and 57.4% of cases, respectively (chi-square, P = .001).

CONCLUSIONS

DCUS offers a noninvasive approach for the staging of gastric cancer. DCUS was comparable to EUS in tumor depth evaluation but offered an advantage in lymph node detection.

Biologic and clinical features of benign solid and cystic lesions of the liver

The widespread use of imaging analyses, either routinely or to evaluate symptomatic patients, has increased the detection of liver lesions (tumors and cysts) in otherwise healthy individuals. Although some of these incidentally discovered masses are malignant, most are benign and must be included in the differential diagnosis. The management of benign hepatic tumors ranges from conservative to aggressive, depending on the nature of the lesions. New imaging modalities, increased experience of radiologists, improved definition of radiologic characteristics, and a better understanding of the clinical features of these lesions have increased the accuracy of diagnoses and reduced the need for invasive diagnostic tests. These advances have led to constant adjustments in management approaches to benign hepatic lesions. We review the biologic and clinical features of some common hepatic lesions, to guide diagnosis and management strategies.

Source and clinical motivation of orders for contrast-enhanced sonography (CEUS) of the liver: A prospective single-center survey

Contrast-enhanced sonography (CEUS) has become a routine part of diagnostic imaging of the liver. Its possibilities, limitations, and indications have been defined in adequately large clinical series and in guidelines and recommendations. We prospectively evaluated physicians' orders for hepatic CEUS received in the radiology department of a large oncology center in Naples, Italy from May 2009 to April 2010. Radiologists performing the CEUS examinations filled out a form that included patient demography, source and type of patient referral, and clinical indications for the examination. During the study period, 564 patients aged 17-86 years (mean, 58 years) were referred to our department for CEUS liver studies (total: 644; 491 outpatient studies, 153 inpatient studies). This included 4 examinations that were ordered by the patient's physician but not performed by our staff. The majority of the CEUS examinations (n = 583; 90.5%) were regularly scheduled procedures ordered by clinical specialists from our center (77.3%) or other centers (11.8%); by general practitioners (on their own initiative) (0.8%); or by other figures (0.6%). The remaining 61 examinations (9.5%) were unscheduled procedures done on the initiative of a radiologist following conventional sonography (US). Fewer than half (47.8%) of the examinations were requested as first-line assessments. The others were ordered to clarify inconclusive findings generated by conventional US (30%) or by a more sophisticated imaging study (CT, MRI, PET) (16.1%) or to resolve discrepancies between CT, MRI, and/or PET findings (6%). CEUS is a relatively noninvasive, low-cost imaging study that is simple to perform and requires no particular patient preparation. This may explain its increasing use to clarify doubts raised by conventional US and other more sophisticated imaging studies.

Incidental Findings: A Case Study of Benign Liver Masses

Frequently, liver masses are found in the course of medical imaging examinations. This article presents a unique case study with multiple benign liver masses: hemangiomas, focal nodular hyperplasias (FNHs), and liver cell adenomas (LCAs). Most hemangiomas have a characteristic echogenic appearance on sonography and need no further workup. FNH may be difficult to visualize sonographically because it is composed of normal hepatocytes in an abnormal arrangement. LCAs and liver adenomatosis are more serious, requiring medical intervention and monitoring.

Contrast-enhanced ultrasound vs multidetector-computed tomography for detecting liver metastases in colorectal cancer: a prospective, blinded, patient-by-patient analysis

AIM

This study compared the sensitivity and specificity of contrast-enhanced ultrasound (CEUS) and multidetector-computed tomography (MDCT) in the detection of liver metastases in patients with colorectal cancer.

METHOD

Between September 2004 and December 2008, 271 consecutive patients (146 men and 125 women; median age 68 years, range: 34-91 years) with primary colorectal cancer were evaluated. All underwent combined liver ultrasound and CEUS following intravenous injection of 2.4 ml of SonoVue(TM). The interval from injection to arrival time in the hepatic vein (ATHV) was noted. Contrast-enhanced MDCT in the portal phase was performed and interpreted blindly. In all patients, intra-operative ultrasound was used as the reference point. In addition, magnetic resonance imaging (MRI) or biopsy was performed on all suspicious lesions or if there was inconsistency in the results.

RESULTS

Liver metastases were detected in 21 (8%) patients. Both CEUS and MDCT had a sensitivity of 85.7%, with respective specificities of 97.6% and 95.6%, and positive predictive values of 75%vs 62%. The negative predictive value of both methods was 99%. In patients with and without liver metastases, ATHV was 18 and 22 s, respectively (P < 0.05).

CONCLUSION

CEUS has potential as a diagnostic alternative to MDCT in the detection of liver metastases. ATHV was shorter in patients with liver metastases.

Contrast-enhanced ultrasound in diagnosis and characterization of focal hepatic lesions

The extensive use of imaging techniques in differential diagnosis of abdominal conditions and screening of hepatocellular carcinoma in patients with chronic hepatic diseases, has led to an important increase in identification of focal liver lesions. The development of contrast-enhanced ultrasound (CEUS) opens a new window in the diagnosis and follow-up of these lesions. This technique offers obvious advantages over the computed tomography and magnetic resonance, without a decrease in its sensitivity and specificity. The new second generation contrast agents, due to their intravascular distribution, allow a continuous evaluation of the enhancement pattern, which is crucial in characterization of liver lesions. The dual blood supply in the liver shows three different phases, namely arterial, portal and late phases. The enhancement during portal and late phases can give important information about the lesion’s behavior. Each liver lesion has a different enhancement pattern that makes possible an accurate approach to their diagnosis. The role of emerging techniques as a contrast-enhanced three-dimensional US is also discussed. In this article, the advantages, indications and technique employed during CEUS and the different enhancement patterns of most benign and malignant focal liver lesions are discussed.

Differentiation of hepatocellular adenoma and focal nodular hyperplasia using 18F-fluorocholine PET/CT

The aim of this pilot study was to evaluate the use of PET/CT with ¹⁸F-fluorocholine in the differentiation of hepatocellular adenoma (HCA) from focal nodular hyperplasia (FNH). Patients with liver lesions larger than 2 cm suspicious for HCA or FNH were prospectively included. All patients underwent PET/CT with ¹⁸F-fluorocholine and histopathological diagnosis was obtained by either liver biopsy or surgery. The ratios between the maximum standardized uptake value (SUV) of the lesion and the mean SUV of normal liver parenchyma were calculated and a receiver operating characteristic (ROC) curve analysis was performed. Ten patients with FNH and 11 with HCA were included. The mean SUV ratio was 1.68±0.29 (±SD) for FNH and 0.88±0.18 for HCA (p<0.001). An SUV ratio cut-off value between 1.12 and 1.22 differentiated patients with FNH from those with HCA with 100% sensitivity and 100% specificity. This pilot study showed that PET/CT with ¹⁸F-fluorocholine can differentiate HCA from FNH.

Focused ultrasound as a local therapy for liver cancer

Conventional surgical treatments of liver cancer are invasive (including minimally invasive) with a high incidence of new metastasis and poor success, even after multiple resections or ablations. These limitations motivated research into new, less invasive solutions for liver cancer treatment.Focused ultrasound surgery (FUS), or high-intensity focused ultrasound, has been recognized as a noninvasive technology for benign and malignant tumor treatment. Previously, FUS was guided with ultrasound that has limited target definition and monitoring capability of the ablation process. Combining magnetic resonance imaging (MRI) with multiple-element phased-array transducers to create MRI-guided focused ultrasound thermal therapy provides more accurate targeting and real-time temperature monitoring. This treatment is hindered by the ribcage that limits the acoustic windows to the liver and the respiratory motion of the liver. New advances in MRI and transducer design will likely resolve these limitations and make MRI-guided FUS a powerful tool in local liver cancer therapy. This article reviews this technology and advances that can expand its use for cancer treatment in general and liver cancer in particular.

Clinical application of contrast-enhanced ultrasonography in diagnosis of superficial lymphadenopathy

OBJECTIVE

The purpose of this study was to evaluate the value of contrast-enhanced ultrasonography (CEUS) in differential diagnosis of superficial lymphadenopathy.

METHODS

Ninety-four superficial enlarged lymph nodes in 94 patients were studied by conventional ultrasonography (gray scale and color Doppler) and CEUS. Contrast-enhanced sonograms were analyzed using contrast-specific quantification software. All of the results were compared with pathologic diagnoses.

RESULTS

Of the 94 lymph nodes examined, 44 were benign and 50 were malignant (33 metastases and 17 lymphomas). The sensitivity, specificity, and accuracy of conventional ultrasonography in differential diagnosis between benign and malignant nodes were 51%, 47%, and 55%, respectively. Contrast-enhanced ultrasonography showed intense homogeneous enhancement in 39 of 44 benign lymph nodes, inhomogeneous enhancement in 32 of 33 metastases, and intense homogeneous enhancement and absence of perfusion in 9 of 17 and 6 of 17 lymphomas, respectively. The sensitivity specificity, and accuracy of CEUS were 84%, 79%, and 80%. After time-intensity curve gamma variates were calculated, the area under the curve of the benign lymph nodes was greater than those of the metastatic lymph nodes and lymphomas (P < .01).

CONCLUSIONS

These results indicate that the use of CEUS and contrast-specific software has a higher degree of diagnostic accuracy than conventional ultrasonography for evaluations of superficial lymphadenopathy. The contrast enhancement patterns and time-intensity curves provide valuable diagnostic information for differential diagnosis of benign and malignant lymph nodes.

Contrast enhanced ultrasound of hepatocellular carcinoma

Sonazoid (Daiichi Sankyo, Tokyo, Japan), a second-generation of a lipid-stabilized suspension of a perfluorobutane gas microbubble contrast agent, has been used clinically in patients with liver tumors and for harmonic gray-scale ultrasonography (US) in Japan since January 2007. Sonazoid-enhanced US has two phases of contrast enhancement: vascular and late. In the late phase of Sonazoid-enhanced US, we scanned the whole liver using this modality at a low mechanical index (MI) without destroying the microbubbles, and this method allows detection of small viable hepatocellular carcinoma (HCC) lesions which cannot be detected by conventional US as perfusion defects in the late phase. Re-injection of Sonazoid into an HCC lesion which previously showed a perfusion defect in the late phase is useful for confirming blood flow into the defects. High MI intermittent imaging at 2 frames per second in the late phase is also helpful in differentiation between necrosis and viable hypervascular HCC lesions. Sonazoid-enhanced US by the coded harmonic angio mode at a high MI not only allows clear observation of tumor vessels and tumor enhancement, but also permits automatic scanning with Sonazoid-enhanced three dimensional (3D) US. Fusion images combining US with contrast-enhanced CT or contrast-enhanced MRI have made it easy to detect typical or atypical HCC lesions. By these methods, Sonazoid-enhanced US can characterize liver tumors, grade HCC lesions histologically, recognize HCC dedifferentiation, evaluate the efficacy of ablation therapy or transcatheter arterial embolization, and guide ablation therapy for unresectable HCC. This article reviews the current developments and applications of Sonazoid-enhanced US and Sonazoid-enhanced 3D US for diagnosing and treating hepatic lesions, especially HCC.

Incidental focal solid liver lesions: diagnostic performance of contrast-enhanced ultrasound and MR imaging

OBJECTIVE

To prospectively assess the diagnostic performance of contrast-enhanced ultrasound (CEUS) and MR imaging in incidental solid focal liver lesions not characterised on ultrasound.

MATERIALS AND METHODS

Forty-seven patients with 50 lesions underwent MR imaging and CEUS: 24 focal nodular hyperplasias (FNH), 11 adenomas, 10 haemangiomas, 1 focal fatty change and 4 malignant lesions were identified. Two experienced radiologists randomly reviewed contrast-enhanced MR imaging and CEUS data, and provided the most likely diagnosis. Sensitivity (Se), specificity (Sp), likelihood ratios (LR) and kappa value were calculated.

RESULTS

A histotype diagnosis was obtained in 66-52% with MR imaging and 52-53% with CEUS, respectively, for both readers. Se, Sp and LR for haemangioma were 100-100, 100-100 and 78-78 with MR imaging and 89-89, 100-100 and 68-70 with CEUS; for FNH with MR imaging they were 88-63, 96-100 and 23-34 and 74-67, 88-96 and 6-17 with CEUS. If the diagnosis of haemangioma was uncertain with CEUS, MR imaging always confirmed the diagnosis. If the diagnosis of FNH was uncertain with either CEUS or MR imaging, the other imaging technique confirmed the diagnosis in approximately half the cases.

CONCLUSION

Both CEUS and MR imaging have a high diagnostic performance in incidental focal liver lesions and are complementary when diagnosis is uncertain.