Determination and prospective validation of cut-off values for the diagnosis of liver cirrhosis for point shear-wave elastography/acoustic radiation force impulse imaging using the ACUSON Sequoia ultrasound system

OBJECTIVES

Point shear-wave elastography (pSWE) alias acoustic radiation force impulse (ARFI) imaging is a well-established ultrasound-based technique for the non-invasive assessment of liver tissue stiffness. As cut-off values for liver cirrhosis cannot be transferred from one ultrasound system to another, this study aimed at determining cut-off values for the newly developed Siemens ACUSON Sequoia ultrasound system.

METHODS

In a pilot study phase, two independent examiners conducted 10 pSWE measurements in an elasticity phantom and 32 healthy individuals for the determination of inter-examiner agreement. Afterwards, 22 cirrhotic patients and 57 patients with chronic liver disease undergoing liver biopsy underwent pSWE. Patient characteristics and stiffness values were compared for individuals with and without liver cirrhosis. Diagnostic accuracies of cut-off values for the diagnosis of liver cirrhosis were calculated using areas under the receiver operating characteristics analysis and Youden's index. In a subsequent validation study phase, these cut-off values were validated prospectively in 107 cirrhotic and 68 non-cirrhotic patients.

RESULTS

Inter-examiner agreement was excellent for measurements in the elasticity phantom (intra-class correlation coefficient [ICC] = 0.998; P  < 0.001), and good for measurements in patients (ICC = 0.844; P  < 0.001). The best cut-off value for the diagnosis of liver cirrhosis was 1.405 m/s with an AUC of 0.872, a sensitivity of 88.2% and a specificity of 88.2% ( P  < 0.001).

CONCLUSION

ARFI elastography using the Siemens ACUSON Sequoia showed a good inter-examiner agreement. The optimal cut-off value was lower than the cut-off values described for former generations of ultrasound devices. These preliminary results should be confirmed in larger patient collectives with histology as the reference standard.

Acoustic radiation force impulse (ARFI) elastography of the bowel wall as a possible marker of inflammatory activity in patients with Crohn's disease

AIM

To evaluate acoustic radiation force impulse (ARFI) shear-wave velocities of the bowel wall in patients with Crohn's disease (CD).

MATERIAL AND METHODS

ARFI shear-wave elastography was analysed within the wall of the stomach, terminal ileum, and sigmoid, and correlated with ultrasound signs of activity in CD patients both retrospectively and in a prospective cohort.

RESULTS

A total of 77 retrospective and 21 prospective CD patients were included. ARFI elastography in the stomach, the normal ileum, and sigmoid was lower than in ileitis or sigmoiditis. Retrospectively, the ARFI values correlated with the bowel wall thickness and Limberg vascularisation score. Prospectively, there was no correlation between ARFI and bowel wall thickness, Limberg score, clinical activity, or C-reactive protein. A cut-off analysis of 105 ileal ARFI measurements showed a cut-off value of 1.92 m/s for the diagnosis of ileal inflammation with 75.3% sensitivity and 87.5% specificity.

CONCLUSION

In patients with CD, ARFI shear-wave velocities show a trend to higher values in inflamed bowel wall thickening on B-mode ultrasound; however, the differences appear small and may not be clinically significant. The factors influencing ARFI measurements of the bowel wall require further investigation.

Spectrum, Applicability and Diagnostic Capacity of Contrast-Enhanced Ultrasound in Pediatric Patients and Young Adults after Intravenous Application - A Retrospective Trial

Purpose: To investigate the spectrum, applicability and diagnostic capacity of intravenous contrast-enhanced ultrasound imaging (CEUS) in a pediatric population. Materials and Methods: From 08/2005 to 11/2015, n = 40 pediatric patients and young adults from 0 - 26 years (Ø 11.4 ± 7.5) and 3.0 - 85.3 kg (Ø 40.8 ± 25.6) with n = 55 investigations received n = 79 IV applications of ultrasound contrast agent (UCA). UCA dose and side effects were documented. Scanned organs were the liver (n = 42), spleen (n = 9), kidney (n = 3), and testis (n = 1). Histology, surgery or reference imaging was compared to CEUS and clinical follow-up. Results: The UCA dose < 20 kg was 0.4 ± 0.3 ml, (0.05 ± 0.02 ml/kg) and > 20 kg was 1.0 ± 0.4 ml (p< 0.0001) (0.02 ± 0.01 ml/kg, p< 0.0001). Adverse effects occurred in 2/79 applications (2.5 %). Agreement CEUS/gold standard resulted in 32/34 investigations. For liver diagnostics (gold standard: MRI, CT, histology, serology), n = 11 malignant and n = 15 benign focal liver lesions were included. The specificity was 100 % (95 % CI: 0.77 - 1.00), the sensitivity was 82 % (95 % CI: 0.48 - 0.98), the positive predictive value was 100 % (95 % CI: 0.69 - 1.00) and the negative predictive value was 88 % (95 % CI: 0.62 - 0.98, p< 0.0001). In n = 2 reference imaging misdiagnosed and CEUS was in accordance with clinical follow-up. All splenic/renal lesions were diagnosed correctly. In n = 1 an insufficient testicular perfusion was ruled out. The observation time was 30.4 ± 30.5 months. Conclusion: CEUS is a well-tolerated and diagnostically equivalent modality in pediatric care, providing fundamental advantages compared to currently approved imaging modalities for these age groups.

LI-RADS-CEUS - Proposal for a Contrast-Enhanced Ultrasound Algorithm for the Diagnosis of Hepatocellular Carcinoma in High-Risk Populations

Purpose: To develop a contrast-enhanced ultrasound algorithm (LI-RADS-CEUS = liver imaging reporting and data system with contrast-enhanced ultrasound) for the diagnosis of hepatocellular carcinoma (HCC) in patients at risk. Materials and Methods: A CEUS algorithm (LI-RADS-CEUS) was designed analogously to CT- and MRI-based LI-RADS. LI-RADS-CEUS was evaluated retrospectively in 50 patients at risk with confirmed HCC or non-HCC lesions (test group) with subsequent validation in a prospective cohort of 50 patients (validation group). Results were compared to histology, CE-CT and CE-MRI as reference standards. Results: Tumor diagnosis in the test group/validation group (n = 50/50) were 46/41 HCCs, 3/3 intrahepatic cholangiocellular carcinomas (ICCs) and 1/6 benign lesions. The diagnostic accuracy of LI-RADS-CEUS for HCC, ICC and non-HCC-non-ICC-lesions was 89 %. For the diagnosis of HCC, the diagnostic accuracy was 93.5 % (43/46 cases) in the test group and 95.1 % (39/41 cases) in the validation group. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 94.3 %, 66.6 %, 94.3 % and 66.6 %, respectively (mean values from both cohorts). Histological findings of HCC were available in 40 versus 23 cases (in total: G1 / G2/G3: 15/35/13). Arterial hyperenhancement was seen in 68/87 (78.2 %) of HCCs. Arterial hyperenhancement with subsequent portal venous or late phase hypoenhancement was seen in 66 % of HCCs. Conclusion: LI-RADS-CEUS offers a CEUS algorithm for standardized assessment and reporting of focal liver lesions in patients at risk for HCC. Arterial hyperenhancement in CEUS is the key feature for the diagnosis of HCC in patients at risk, whereas washout is not a necessary prerequisite.

Comparison of Acoustic Radiation Force Impulse (ARFI) Elastography Measurements with the 4C1 Transducer to the 6C1HD Transducer: A Phantom and Patient Study

Purpose: The aim of this study was to evaluate whether acoustic radiation force impulse (ARFI) elastography done with the 4C1 probe yields comparable results to the recently introduced 6C1HD probe. Materials and Methods: Measurements with the 4C1 and 6C1HD probes (Acuson S2000) were performed and compared in four different inclusions of an elasticity phantom model (QA049 CIRS) as well as in the liver of healthy individuals and patients with liver cirrhosis. Results: Measurements with the 6C1HD probe were slightly higher in all phantom inclusions (8, 14, 45, 80kPA) with a mean of 1.48 m/s (95 %-CI; 1.47 - 1.49), 2.18 m/s (95 %-CI; 2.17 - 2.19), 3.61 m/s (95 %-CI; 3.57 - 3.64) and 4.34 m/s (95 %-CI; 4.29 - 4.39) compared to the 4C1 transducer with 1.46 m/s (95 %-CI; 1.45 - 1.47), 2.15 m/s (95 %-CI; 2.14 - 2.16), 3.39 m/s (95 %-CI; 3.37 - 3.41) and 3.98 m/s (95 %-CI; 3.75 - 4.21), respectively (p = 0.04, p < 0.01, p < 0.01, p < 0.01). Cirrhotic patients (n = 40) had a higher mean shear wave speed with 3.00 m/s (95 %-CI; 2.80 - 3.21) with the 6C1HD transducer compared to 2.81 m/s (95 %-CI; 2.64 - 2.99) with the 4C1 transducer (p = 0.03). Healthy individuals (n = 20) had a mean shear wave speed of 1.12 m/s (95 %-CI; 1.06 - 1.17) with the 6C1HD probe and 1.12 m/s (95 %-CI; 1.05 - 1.19) with the 4C1 probe (p = 0.96). Conclusion: ARFI values assessed with a 6C1HD transducer are slightly higher than measurements with a 4C1 transducer in an ARFI phantom and in patients with liver cirrhosis. As the difference is small, current cut-off values keep their usefulness but should be interpreted with caution if measurements are close to the cut-off.

A Milestone: Approval of CEUS for Diagnostic Liver Imaging in Adults and Children in the USA

The approval of microbubbles with the inert gas sulfur hexafluoride (SF6) and a palmitic acid shell (SonoVue(®), Bracco Geneva, CH) for the diagnostic imaging of liver tumors in adults and children by the FDA in the United States represents a milestone for contrast-enhanced ultrasound (CEUS).This warrants a look back at the history of the development of CEUS. The first publications based on echocardiographic observations of right ventricular contrast phenomena caused by tiny air bubbles following i. v. injection of indocyanine green appeared around 1970 1 2 3. A longer period of sporadic publications but no real progress then followed since, in contrast to X-ray methods, ultrasound works quite well without a contrast agent.It is noteworthy that the foundations for further development were primarily laid in Europe. The development and approval (1991) of the contrast agent Echovist(®) by a German contrast manufacturer for echocardiography unsuitable for passing through lungcapillaries 4 5 resulted in the first extracardiac indications, e. g. for detecting retrovesical reflux and tubal patency, in the mid-1980 s 6 7 8. The sensitivity of color Doppler was not able to compensate for the lack of an ultrasound contrast agent compared to CT with its obligatory contrast administration.Studies of SHU 508 - microbubbles of air moderately stabilized with galactose and palmitic acid - began in 1990 9 10 11 12 13 14 15 and the contrast agent was then introduced in 1995 in Germany as Levovist(®). The most important publications by Blomley, Cosgrove, Leen, and Albrecht are named here on a representative basis 16 17 18 19 20.SHU 508 along with other US contrast agents provided impressive proof of the superiority of CEUS for the diagnosis of liver metastases. However, practical application remained complicated and required skill and technical know-how because of a lack of suitable software on US units 21 22 23 24 25. The monograph regarding the use of contrast agent in the liver by Wermke and Gaßmann is impressive but unfortunately only available in German 26. In addition to being applied in the heart and the liver, CEUS was first used in transcranial applications 27 and in vessels 28, the kidneys 29, and the breast 30. Measurements at transit times were also of particular interest 31. It was difficult to convince ultrasound device manufacturers of the need to adapt US units to US contrast agents and not vice versa.The breakthrough came with low MI phase contrast inversion and the introduction of SonoVue(®) in many European countries in 2001. This more stable US contrast agent is easy to use and is becoming indispensable in diagnostic imaging of the liver 32 33 34 35 36 37 38 39 40. Studies have shown its excellent tolerability 41 and diagnostic reliability comparable to that of MDCT and MRI in the liver 42 43. Today it would be unimaginable to diagnose liver tumors without CEUS 44. This also applies to very small lesions 45 46.EFSUMB published the first CEUS guidelines in 2004 47 which have since been reissued and divided into hepatic 48 and extrahepatic applications 49. The first recommendations regarding quantitative assessment have also been published 50.The increasing scientific interest in CEUS is evident based on the greater number of PubMed hits for Echovist(®) (ca. 130), Levovist(®) (ca. 500) and SonoVue(®) (ca. 1500) as well as on the fact that publications regarding CEUS comprise almost 20 % of UiM/EJU articles in the last 10 years. The number of CEUS articles in UiM/EJU continues to be high 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75.In the clinical reality, CEUS has been able to become established alongside CT and MRI according to the saying "better is the enemy of good" 76 as the method of choice after B-mode ultrasound in the evaluation of liver tumor malignancy in Germany, where the technically challenging method is promoted. In the case of unclear CT and MRI findings, CEUS performed by an experienced examiner/clinician often provides the solution, particularly in the case of small lesions, and is the last resort before US-guided biopsy 45 46. However, there is a lack of competent CEUS examiners and Germany continues to be the world champion of X-ray examinations with no noticeable reverse trend. In almost every doctor's office and hospital, ultrasound costs are by far not fully covered, resulting in an extremely high frequency of CT use with CT being available to everyone regardless of insurance status.The USA is now in the starting position for CEUS. It will be exciting to see how the method will develop there. The FDA's decision to approve sulfur hexafluoride (Lumason(®) = SonoVue(®)) should be considered against the background of the radiation exposure caused by CT examinations and the fact that MRI using gadolinium-containing contrast agents is no longer considered noninvasive because of nephrogenic systemic fibrosis (NSF) and the accumulation of the agent in the cerebrum. An essential point of the campaign regarding the avoidance of diagnostic radiation exposure triggered in the USA by the publications of Brenner et al. 77 78 was that the agent was approved for use in the liver even for children 79 80 - still off label in Europe - without additional comprehensive studies due to the available scientific results and the very low side effects profile of Lumason(®) (= SonoVue(®)). It is admittedly unclear why other indications (except the heart which has been approved since 2014) are excluded even though the microbubbles as a pure blood pool contrast agent can be diagnostically used in the entire vascular system and bed of all organs. To our knowledge, there is no such restriction on the approval of X-ray contrast agents.Like echocardiography and emergency ultrasound, CEUS began in Europe but will probably only establish its final diagnostic value as a "reimport".This is a major opportunity to permanently define the role of Ultrasound as a highly valuable, patient-centered imaging method in the German health care system.This may prompt some of our international readers to reflect upon the role of CEUS in their own countries.

Benefit of Contrast-Enhanced Ultrasound (CEUS) in the Follow-Up Care of Patients with Colon Cancer: A Prospective Multicenter Study

PURPOSE

According to the German guidelines on colorectal cancer, unenhanced ultrasound is recommended for follow-up. On the other hand, ultrasound and radiology societies specify the use of contrast-enhanced ultrasound for ruling out liver metastases. Studies focusing on the follow-up of cancer patients are lacking. The goal of this multicenter study initiated by the German Ultrasound Society (DEGUM) was to determine the potential benefit of contrast-enhanced ultrasound in the follow-up of patients with colon cancer.

MATERIALS AND METHODS

Follow-up patients with colon cancer (UICC > IIa) were investigated. As scheduled according to the German guidelines, unenhanced ultrasound was performed followed by contrast-enhanced ultrasound. All liver lesions were recorded. In case of additional metastases detected on contrast-enhanced ultrasound, contrast-enhanced CT, MRI or biopsy was performed to confirm additional liver metastases.

RESULTS

A total of 45 liver metastases were detected in 26/290 patients (= 9 %) using unenhanced ultrasound. A further 28 metastases were detected on contrast-enhanced ultrasound in these 26 patients. In 18 patients showing no liver metastases, 40 additional metastases were detected on unenhanced ultrasound. This means that 44 patients with a total of 113 liver metastases were detected on contrast-enhanced ultrasound (p = 0.0006).

CONCLUSION

Contrast-enhanced ultrasound should be recommended in the follow-up of patients with colon cancer in addition to unenhanced ultrasound - the up-to-date standard.

Prospective Evaluation of Acoustic Radiation Force Impulse (ARFI) Elastography and High-Frequency B-Mode Ultrasound in Compensated Patients for the Diagnosis of Liver Fibrosis/Cirrhosis in Comparison to Mini-Laparoscopic Biopsy

PURPOSE

Ultrasound is a well-established noninvasive test for assessing patients with liver disease. This study aims to prospectively compare ultrasound to the new technique elastography (ARFI) for the assessment of liver fibrosis/cirrhosis.

MATERIALS AND METHODS

High-frequency B-mode ultrasound (liver surface/vein irregularity, liver homogeneity, spleen size), ARFI quantification, mini-laparoscopic liver evaluation including biopsy were prospectively obtained in compensated patients scheduled for liver biopsy. For the diagnosis of cirrhosis, a combined gold standard (cirrhosis at histology and/or at macroscopic liver evaluation) was used.

RESULTS

Out of 157 patients, 35 patients were diagnosed cirrhotic. Ultrasound (combination of liver vein and/or surface irregularity) showed no significant difference compared to ARFI quantification for the diagnosis of significant liver fibrosis (Ishak> = 3) and cirrhosis. Diagnosis of cirrhosis had a sensitivity/specificity/PPV/NPV of 83 %(± 12) / 82 %(± 7) / 57 %(± 14) / 94 %(± 4), respectively, with ultrasound and 86 %(± 12) / 81 %(± 7) / 57 %(± 13) / 95 %(± 4), respectively, with ARFI quantification. The sensitivity/specificity/PPV/NPV for the detection of significant fibrosis were 68 %(± 13) / 86 %(± 7) / 71 %(± 13) / 84 %(± 7), respectively, for ultrasound and 70 %(± 12) / 84 %(± 7) / 69 %(± 12) / 84 %(± 7), respectively, for ARFI quantification.

CONCLUSION

ARFI elastography and high-frequency B-mode ultrasound show similar and good results for the diagnosis of compensated liver cirrhosis and high-grade fibrosis. A key benefit of both methods is the high NPV suggesting them as noninvasive exclusion tests.

[Contrast-enhanced Ultrasound in Diagnostic Imaging of Muscle Injuries: Perfusion Imaging in the Early Arterial Phase]

BACKGROUND

Ultrasound is a standard procedure widely used in the diagnostic investigation of muscle injuries and widely described in the literature. Its advantages include rapid availability, cost effectiveness and the possibility to perform a real-time dynamic examination with the highest possible spatial resolution. In the diagnostic work-up of minor lesions (muscle stiffness, muscle strain), plain ultrasound has so far been inferior to MRI. The case presented by us is an example of the possibilities offered by contrast-enhanced ultrasound (CEUS) in the imaging of muscle injuries compared with plain B-mode image ultrasound and MRI imaging of the affected region.

MATERIAL/METHODS

This case report is about a high-performance football player who sustained a muscle injury. He underwent an ultrasound examination (S 2000, 9L4 Probe, Siemens, Germany), which was performed simultaneously in the conventional and contrast-enhanced mode at the level of the lesion. An intravenous bolus injection of 4.8 ml of intravascular contrast agent (SonoVue(®), Bracco, Italy) was given via a cubital intravenous line. After that, the distribution of contrast agent was visualised in the early arterial phase. In addition, a plain magnetic resonance imaging scan of both thighs was performed for reference.

RESULTS

On conventional ultrasound, the lesion was not clearly distinguishable from neighbouring tissue, whereas contrast-enhanced ultrasound demonstrated a well delineated, circumscribed area of impaired perfusion with hypoenhancement compared with the surrounding muscles at the clinical level of the lesion in the arterial wash-in phase (0-30 sec, after intravenous administration). The MRI scan revealed an edema signal with perifascial fluid accumulation in the corresponding site.

CONCLUSION

The use of intravascular contrast agent enabled the sensitive detection of a minor injury by ultrasound for the first time. An intramuscular edema seen in the MRI scan showed a functional arterial perfusion impairment on ultrasound, which was sensitively detected in the early phase. Further examinations must be performed on muscle injuries of various degrees of severity in order to validate the application of this procedure and to standardise the examination process.

Quantitative perfusion analysis in pancreatic contrast enhanced ultrasound (DCE-US): a promising tool for the differentiation between autoimmune pancreatitis and pancreatic cancer

In the work-up of focal pancreatic lesions autoimmune pancreatitis (AIP) is a rare differential diagnosis to pancreatic cancer (PC) with similar clinical constellations. The aim of our study was to compare differences between proven AIP and PC using transabdominal dynamic contrast enhanced ultrasound (DCE-US). Therefore we recorded 3-minute-clips of CEUS examinations and analyzed perfusion parameters with VueBox®-quantification software. To obtain DCE-US Parameters, Regions-of-Interest were selected within the lesions and the surrounding pancreas parenchyma, serving as reference tissue. We compared 3 patients with AIP (mean age: 58 years; lesion mean size: 40 mm) to 17 patients with PC (mean age: 68 years; lesion mean size: 35.9 mm). Significant differences between PC and parenchyma could be found in the following parameters: Peak-Enhancement (PE), Wash-in-and-Wash-out-AUC, Wash-in Perfusion-Index. PE of AIP was comparable to normal parenchyma. The relation of PE between parenchyma and lesion (ΔPE) AIP and PC was significantly different [AIP: 0.21 (±0.06); PC: 0.81 (±0.1); p<0.01]. PE of neoplastic lesions was significantly lower as AIP and normal parenchyma (p<0.01). Therefore perfusion analysis in DCE-US can help to differentiate hypovascular PC from AIP presenting nearly isovascular time intensity curves. Diagnostic accuracy of DCE-US in this setting has to be validated in future prospective studies in comparison to CT and MRI.

EFSUMB Guidelines on Interventional Ultrasound (INVUS), Part I. General Aspects (long Version)

This is the first part of the Guidelines on Interventional Ultrasound of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) and covers all general aspects of ultrasound-guided procedures (long version).

EFSUMB Guidelines on Interventional Ultrasound (INVUS), Part I. General Aspects (Short Version)

This is the first part of the Guidelines on Interventional Ultrasound of the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) and covers all general aspects of ultrasound-guided procedures (short version; the long version is published online).

CEUS in hepatocellular carcinoma and intrahepatic cholangiocellular carcinoma in 320 patients - early or late washout matters: a subanalysis of the DEGUM multicenter trial

PURPOSE

The aim of the study was the comparison of tumor vascularization and contrast enhancement in contrast-enhanced ultrasound (CEUS) for the characterization of hepatocellular carcinoma (HCC) and intrahepatic cholangiocellular carcinoma (ICC). We present data of the subpopulations HCC and ICC examined in the DEGUM multicenter trial for the characterization of focal liver lesions in clinical practice.

MATERIALS AND METHODS

Based on the data of the DEGUM multicenter trial (1349 patients), all patients with histologically proven HCC (n = 278) and ICC (n = 42) were analyzed. The vascularity pattern and contrast enhancement pattern during the arterial, portal-venous and late phase were compared.

RESULTS

An underlying liver cirrhosis was found in 214/278 patients with HCC (76.9 %) and 7/42 patients with ICC (16.7 %). In CEUS, HCC showed a global arterial hyperenhancement compared to ICC (HCC: tumor center: 60.3 %; tumor periphery: 75 %; ICC: tumor center: 16.7 %; tumor periphery: 40.5 %). ICC showed an initial contrast enhancement primarily at the tumor periphery (ICC: 85.7 % vs. HCC: 61 %) followed by an early portal-venous contrast washout in the tumor center (ICC: 85.8 % vs. HCC: 49.8 %) and tumor periphery (ICC: 66.7 % vs. HCC: 32.6 %). HCC showed a delayed contrast washout (late phase hypoenhancement: HCC: 75 % vs. ICC: 92.9 %).

CONCLUSION

ICCs are rare in cirrhotic livers. CEUS can demonstrate differences in the vascularization patterns between HCC and ICC. HCC showed an arterial global hyperenhancement and delayed contrast washout in the late phase. ICCs are characterized by an arterial contrast enhancement at the tumor periphery with early contrast washout of the vascularized parts of the lesions in the portal-venous and late phase.

Statement of the section internal medicine of the DEGUM - ultrasound obtains pole position for clinical imaging in acute diverticulitis

This paper reviews and interprets the role of ultrasonography in view of the recently published Guideline on diverticular disease of the Consensus conference of the German Societies of Gastroenterology (DGVS) and Visceral Surgery (DGAV) implying a new classification of diverticular disease (CDD). Qualified US is not only equipotent to qualified CT and frequently effectual for diagnosis but considers relevant legislation for radiation exposure protection. Unsurpassed resolution allows detailed resolution thereby allowing to differentiate and stratify the relevant types of diverticular disease. Subsequently, US is considered the first choice of imaging in diverticular disease. Vice versa, CT has definite indications in unclear / discrepant situations – or insufficient US-performance.

Incidence of bleeding in 8172 percutaneous ultrasound-guided intraabdominal diagnostic and therapeutic interventions - results of the prospective multicenter DEGUM interventional ultrasound study (PIUS study)

PURPOSE

To analyse the incidence of bleeding after percutaneous ultrasound guided diagnostic and therapeutic intraabdominal interventions in a prospective multicentre study (DEGUM percutaneous interventional ultrasound study).

MATERIALS AND METHODS

Within a time period of 2 years diagnostic and therapeutic intraabdominal interventions (with the exclusion of ascites paracentesis) performed percutaneously under continuous ultrasound (US) guidance were prospectively assessed using a pseudonymized standardized web site entry form. Number and type of intervention, operator experience, patient characteristics, medication, lab data as well as technical aspects of the procedure and bleeding complications were analysed according to the interventional radiology standards.

RESULTS

8172 US-guided intraabdominal interventions (liver n = 5903; pancreas n = 501, kidney n = 434, lymph node = 272, biliary system n = 153, spleen n = 63, other abdominal organs and extra-organic targets n = 999) were analysed in 30 hospitals. The majority were diagnostic biopsies including 1780 liver parenchyma, 3400 focal liver lesions and 404 pancreatic lesions. 7525 interventions (92.1 %) were performed in hospitalized patients (mean age 62.6 years). Most operators were highly experienced in US-guided interventions (> 500 interventions prior to the study n = 5729; 70.1 %). Sedation was administered in 1131 patients (13.8 %). Needle diameter was ≥ 1 mm in 7162 punctures (87.9 %) with main focus on core needle biopsies (18 G, n = 4185). Clinically relevant bleeding complications with need of transfusion (0.4 %), surgical bleeding control (0.1 %) and radiological coiling (0.05 %) were very rare. Bleeding complications with fatal outcome occurred in four patients (0.05 %). The frequency of major bleeding complications was significantly higher in patients with an INR > 1.5 (p < 0.001) and patients taking a medication potentially interfering with platelet function or plasmatic coagulation (p < 0.0333).

CONCLUSION

This prospective multicentre study confirms the broad spectrum of percutaneous US-guided intraabdominal interventions. However diagnostic liver biopsies dominate with the use of core needle biopsies (18 G). Percutaneous US-guided interventions performed by experienced sonographers are associated with a low bleeding risk. Major bleeding complications are very rare. A pre-interventional INR < 1.5 and individual medication risk assessment are recommended.

Dynamic contrast-enhanced ultrasound (DCE-US) for the characterization of hepatocellular carcinoma and cholangiocellular carcinoma

PURPOSE

In a prospective study, we compared the different perfusion kinetics of HCC and ICC using dynamic contrast-enhanced ultrasound (DCE-US).

MATERIALS AND METHODS

Patients with proven HCC and ICC were included. Three-minute video clips of CEUS examinations (CPS - low MI mode) after a bolus injection of 1.2 ml SonoVue were recorded and analyzed with quantification software (VueBox). Parameters for the arterial contrast enhancement [rise time (RT), time-to-peak (TTP)] towards portal venous contrast enhancement [mean transit time (local) (mTTl) and fall time (FT)] were quantified. Furthermore, contrast wash-out after peak enhancement (PE) (40 s, 80 s, 100 s and 120 s after PE) was compared between HCC and ICC.

RESULTS

43 patients with proven HCC (n = 23 HCC; cirrhosis n = 16) and ICC (n = 20 ICC; Cirrhosis n = 6) were examined. No statistical difference of the arterial DCEUS parameters was found between HCC and ICC. Contrast enhancement of the portal venous and late phases showed significantly lower values in the ICC group indicating early wash-out of the contrast agent: mTTl (p = 0.0209): HCC 118.4 s (SD± 88.4); ICC 64.8 s (SD± 49.7). FT (p = 0.0433): HCC 42.5 s (SD± 27.7); ICC 27.7 s (SD± 16.2). The percental loss of intensity at a definite time point after PE was significantly higher in ICC than in HCC lesions.

CONCLUSION

DCE-US is able to detect and quantify differences in perfusion kinetics between HCC and ICC. Whereas arterial contrast enhancement patterns may overlap between HCC and ICC, a timed characterization of wash-out kinetics may offer an additional tool to characterize HCC and ICC. The presence of a rapid loss of signal intensity in the early portal venous phase is significantly higher in ICC than in HCC lesions.

Liver stiffness assessed by acoustic radiation force impulse (ARFI) technology is considerably increased in patients with cholestasis

PURPOSE

To explore the impact of cholestasis on liver stiffness assessed by acoustic radiation force impulse (ARFI) technology.

MATERIALS AND METHODS

Over a period of four months, patients with sonographic cholestasis and increased cholestatic blood values (Bilirubin, γGT, AP > 2 times ULN) scheduled for endoscopic therapy were recruited. Exclusion criteria were: known liver disease; signs of cirrhosis at ultrasound (irregular liver veins and/or surface); heart insufficiency (NYHA III-VI). ARFI (Siemens S2000), ultrasound and blood examinations were performed before and in a subgroup after successful biliary drainage.

RESULTS

In total, 21 patients with cholestasis were included in the study. ARFI measurements were above the cut-off for cirrhosis (1.8  m/s) in all patients with a mean of 2.91  m/s ± 0.89  m/s without a history or signs of cirrhosis. Bilirubin, γGT and AP were elevated on average to 9.7 ± 5.3  mg/dl, 1192 ± 960  U/l and 730 ± 389  U/l. A subgroup of 10 patients was measured after successful drainage. ARFI measurements declined in all patients of that subgroup on average by 0.76  m/s at a mean time interval of 4.5 days (p < 0.001).

CONCLUSION

Cholestasis significantly increases liver stiffness assessed by ARFI. Therefore, it is important to exclude profound cholestasis when using ARFI for evaluating patients for liver fibrosis.

Postinterventional pain and complications of sonographically guided interventions in the liver and pancreas

PURPOSE

Sonographically guided interventions in abdominal organs are routine procedures with rare severe complications. However, potential patient discomfort or pain is frequently not addressed in the literature.

MATERIALS AND METHODS

In a prospective 1-year study, the peri- and postinterventional pain of patients undergoing sonographically guided punctures of the liver and pancreas was analyzed. Data acquisition was done with a standardized questionnaire. This included three numeric rating scales (NRS) ranging from "0" to "10" to be answered at puncture and 1 hour and 4 hours later. Data concerning complications and administered analgesic medication was acquired from the patients' charts.

RESULTS

223/274 patients could be analyzed (83 %). 91 women (40.8 %) and 132 men (59.2 %) were included. The mean age was 56.0 yrs. Overall the average level of pain was 2.98  at puncture, 1.21 after 1 hour and 0.71 after 4 hours. In patients with diagnostic biopsies, the pain levels were 3.37(0  h)/1.33(1  h)/0.71(4  h) for liver parenchyma, 2.64(0  h)/0.95(1  h)/0.65(4  h) for focal liver lesions and 3.1(0  h)/1.9(1  h)/1.1(4  h) for pancreatic punctures. The pain levels at therapeutic interventions were 3.00(0  h)/2.00(1  h)/0.50(4  h). Female and younger (< 50 yrs) patients had statistically significantly more pain at puncture and 1 hour postintervention. Only minor complications occurred (0.9 %).

CONCLUSION

Severe pain after sonographically guided interventions is rare. Most patients suffer only from mild pain postinterventionally.

Acoustic radiation force impulse (ARFI) and high-frequency ultrasound of the liver surface for the diagnosis of compensated liver cirrhosis

PURPOSE

To evaluate the diagnostic value of acoustic radiation force impulse (ARFI) and high-frequency ultrasound of the liver surface, using histology as a gold standard for the diagnosis of compensated liver cirrhosis.

MATERIALS AND METHODS

73 patients without ascites undergoing liver biopsy were included in the study. The left and right liver lobes were examined with ARFI and high-frequency ultrasound. Liver surface irregularity was quantified using image analysis software to calculate the difference between the real surface and the approximated physiological surface through a 20 mm standardized line.

RESULTS

There is a significant difference between cirrhotic and non-cirrhotic patients for both quantified liver surface (QLS) and ARFI (p < 0.001). The mean values for QLS of the left lobe were 0.71 ± 0.24 mm and 1.17 ± 0.80 mm, of the right lobe 0.56 ± 0.26 mm and 0.87 ± 0.26 mm for non-cirrhotic and cirrhotic patients, respectively. The mean values of ARFI measurements of the left lobe were 2.04 ± 0.76 m/s and 2.85 ± 0.81 m/s, of the right lobe 1.65 ± 0.61 m/s and 3.02 ± 0.77 m/s for non-cirrhotic and cirrhotic patients, respectively. Diagnostic accuracy (AUROC) was 0.78/0.80 for QLS and 0.77/0.91 for ARFI of the left/right lobe, respectively. ARFI of the right lobe is significantly better than ARFI of the left (p = 0.023) or QLS of the left (p = 0.025)/right (p = 0.046) lobe of the liver.

CONCLUSION

Assessment of liver surface irregularity by high-frequency ultrasound (QLS) is a useful diagnostic test for the assessment of compensated liver cirrhosis. ARFI of the right liver lobe is significantly better than high-frequency ultrasound (QLS of the left/right lobe of the liver) and ARFI of the left lobe of the liver.

Outcome analysis of liver stiffness by ARFI (acoustic radiation force impulse) elastometry in patients with chronic viral hepatitis B and C

AIM

To evaluate the association between liver stiffness measured by acoustic radiation force impulse (ARFI) elastometry and the outcome of antiviral treatment in patients with chronic viral hepatitis B and C.

MATERIALS AND METHODS

Thirty-eight patients with chronic viral hepatitis B (n = 16) or hepatitis C (n = 22) underwent liver biopsy and ARFI elastometry of the right hepatic lobe. A follow-up assessment using ARFI was performed a mean of 2.3 years after the baseline evaluation. The patients with favourable outcome were classified in group S and those receiving no treatment, showing no response to treatment, or experiencing a relapse were classified in group N.

RESULTS

The 38 patients had an initial mean ARFI value of 1.56 ± 0.62 m/s as compared with 1.54 ± 0.64 m/s in the follow-up evaluation. Group S showed a significant decline in ARFI values (1.55 ± 0.60 m/s versus 1.34 ± 0.47 m/s; p < 0.05) and included 16 (64%) patients with lower shear wave velocities at follow-up. In group N, liver stiffness values showed a slight but not significant increase (1.57 ± 0.70 m/s versus 1.93 ± 0.77 m/s).

CONCLUSION

Changes in liver stiffness during antiviral therapy can be assessed by ARFI reflecting response or no response. ARFI elastometry is an additional, useful tool for the follow-up assessment of treatment outcome in patients with chronic viral hepatitis B or C infection.

[Diagnosis of and therapy for hepatocellular carcinoma]

The interdisciplinary guidelines at the S3 level on the diagnosis of and therapy for hepatocellular carcinoma (HCC) constitute an evidence- and consensus-based instrument that is aimed at improving the diagnosis of and therapy for HCC since these are very challenging tasks. The purpose of the guidelines is to offer the patient (with suspected or confirmed HCC) adequate, scientifically based and up-to-date procedures in diagnosis, therapy and rehabilitation. This holds not only for locally limited or focally advanced disease but also for the existence of recurrences or distant metastases. Besides making a contribution to an appropriate health-care service, the guidelines should also provide the foundation for an individually adapted, high-quality therapy. The explanatory background texts should also enable non-specialist but responsible colleagues to give sound advice to their patients concerning specialist procedures, side effects and results. In the medium and long-term this should reduce the morbidity and mortality of patients with HCC and improve their quality of life.

Early response to anti-tumoral treatment in hepatocellular carcinoma--can quantitative contrast-enhanced ultrasound predict outcome?

PURPOSE

In order to detect an early response to anti-angiogenic therapy, this study aims at analyzing specific effects of a sorafenib-based regime on intra-tumoral D-CEUS flow parameters of patients with HCC.

MATERIALS AND METHODS

Videos of the arterial phase were captured before initiation of a therapy with sorafenib and 1 and 3 months after (n = 9). Patients receiving a non-anti-angiogenic therapy (TACE, n = 10) served as a comparison group. Cross-sectional imaging was performed at the same time points and patients were followed up for 1 year.

RESULTS

In the responder group (RE), the absolute (percentage) TTP was 11.28 s ± 2.03 s (1.00) before treatment, 13.60 s ± 1.52 s (1.53 ± 0.08) after one month (p = 0.0405), and 16.17 s ± 2.35 s (1.46 ± 0.07) after three months of treatment (p = 0.0071). The TTP increased significantly in the RE group as early as 1 month after initiation of sorafenib compared to the non-responder group. There were no significant differences in the non-responder group or between the NR and the TACE group at any time point. D-CEUS values from all sorafenib-treated patients showed good accordance with RECICL (response evaluation criteria in cancer of the liver) criteria (R2 = 0.7154, p = 0.0001).

CONCLUSIONS

Quantitative CEUS reveals variations of dynamic parameters of blood flow during anti-tumoral therapy in liver cancer patients. Further investigations and clinical trails have to confirm that the TTP is a promising parameter in the prediction of early response to sorafenib-based therapy.

Dynamic contrast-enhanced ultrasound (DCE-US) for easy and rapid evaluation of hepatocellular carcinoma compared to dynamic contrast-enhanced computed tomography (DCE-CT)--a pilot study

PURPOSE

To check the feasibility of the easy quantification of tumor vascularization derived from dynamic contrast-enhanced ultrasound (DCE-US) in comparison to dynamic contrast-enhanced computed tomography (DCE-CT) in patients with hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

19 patients with cirrhosis and histologically proven HCC prospectively underwent CEUS (SonoVue) and CT (Imeron400). Following CEUS, the software ImageJ was used for the easy quantification of the echogenicity in HCC lesions and tumor-free liver parenchyma. For DCE-CT we used the software Hepacare and created arterial enhancement fraction color maps of the whole liver and HCC lesions.

RESULTS

Unifocal/multifocal HCCs were detected in 12/7 (US) and 10/9 patients (CT) and biopsied nodules were defined as a reference lesion with a median of 40 mm (US) and 42 mm (CT). CEUS showed HCC-typical hyper-/hypoenhancement in the arterial/late phase in 16/19 reference lesions, while all reference lesions showed an HCC-typical vascular pattern in CT. With DCE-US, quantitative assessment could not be performed in 3/19 patients due to respiratory motion or insufficient image quality. 13/16 reference lesions showed an HCC-typical vascular pattern. Quantitative assessment was possible with DCE-CT in all patients and all reference nodules showed HCC-typical values of the arterial enhancement fraction. There was no statistical difference between CEUS, DCE-US and DCE-CT in the quantitative assessment of contrast enhancement.

CONCLUSION

The quantitative evaluation of DCE-US was feasible in HCC without a statistical difference with respect to DCE-CT. Further studies with a larger study population including small nodules ≤ 2 cm are needed to assess whether this technique is helpful in routine ultrasound.

Impact of food intake, ultrasound transducer, breathing maneuvers and body position on acoustic radiation force impulse (ARFI) elastometry of the liver

PURPOSE

Since acoustic radiation force impulse (ARFI) elastometry is an increasingly popular method for the assessment of hepatic fibrosis and cirrhosis, we investigated factors possibly influencing hepatic elastometric measurements.

MATERIALS AND METHODS

30 healthy volunteers (17 females, 13 males) were recruited. The shear wave velocity of the right liver lobe was determined in a fasting upright and supine position and after different breathing maneuvers with the convex array (4C1) and in a supine position with the linear (9L4) ultrasound transducer. In 18 volunteers, subsequent measurements were obtained in a fasting state and 30, 60, 90 and 120 min after ingestion of a standardized breakfast. A group of 8 patients (average age: 76 years) with right heart insufficiency was also evaluated.

RESULTS

In the fasting state, the ARFI shear wave velocities measured in an upright position were significantly higher than those in supine position (p< 0.0001). The supine ARFI values were significantly higher with the linear transducer than with the convex transducer (p = 0.0034). The results in deep inspiration, deep expiration and during Valsalva maneuver showed no differences. The food intake-related ARFI elastometric measurements were significantly elevated at time points 30 min (p = 0.019) and 60 min (p = 0.036) postprandial. In right heart insufficiency, the ARFI values were elevated.

CONCLUSION

Hepatic ARFI elastometry is a well evaluated method. A standardized examination should include measuring in a supine position with the convex transducer (4C1) without specific breathing maneuvers. Since ARFI elastometry values increase after food intake, measurements should be performed in the fasting state, or not earlier than 2 hours postprandially. Heart dysfunction may impair ARFI accuracy.

Assessment of bone microcirculation by contrast-enhanced ultrasound (CEUS) and [18F]-positron emission tomography/computed tomography in free osseous and osseocutaneus flaps for mandibular reconstruction: preliminary results

PURPOSE

Postsurgical evaluation of bone microcirculation in osseous and osseocutaneus free flaps by contrast enhanced ultrasound (CEUS) with time intensity curve (TIC) analysis and [18F]-positron emission tomography/computed tomography (Fluoride-PET/CT).

PATIENTS AND METHODS

10 patients with osseous or osseocutaneus microvascular flaps were evaluated with CEUS. Ultrasound was carried out by an experienced examiner with a high resolution linear probe (6-9 MHz, LOGIQ E9, GE) after intravenous bolus injection of 2.4 ml SonoVue® (BRACCO, Germany). Time intensity curves (TIC) in selected regions of interest (ROI) were analyzed and compared with the evaluation of [18F]-positron emission tomography/computed tomography and the clinical course for at least 2 month.

RESULTS

9/10 patients showed evidence for soft tissue and osseous microcirculation of the transplants in CEUS correlating with the clinical course. The soft tissue parts of the transplant showed a mean value of 84% (range 51-98%) and the bone parts a mean value of 39% (range 11-75%) for the Area under the curve (AuC) compared with the AuC for the anastomotic vessel region. Mean values for time to peak (TTP) were 27,1 sec (range 8.7-52.0 sec) for the anastomotic vessels, 29.3 sec (range 7.9-62.0 sec) for the soft tissue of and 32.0 sec (range 7.4-69.0 sec) for the transplant bone. In 1/10 patients flap failure occurred, after denudation the bone was left as an avascular transplant. AuC showed a mean value of 0.5 % for the bone region compared with the vessel region. Fluoride-PET/CT assessed bone vitality in 7 patients as "good" in 1 patient as "uncertain" and in 1 patient as "poor". CEUS assessment was corresponding with Fluoride-PET/CT in 4 patients, clinical assessment in 6 patients.

CONCLUSION

Fluoride-PET/CT is a valuable tool to make an indirect statement about the perfusion of the transplanted bone and was used as control in this study. CEUS is a new and promising method for the evaluation of microcirculation of buried free microvascular bone grafts and the osseous part of osseocutaneous flaps and may be used for a steady monitoring in the first postoperative days.

Mesenteric transit time using contrast-enhanced ultrasound (CEUS) does not correlate with disease activity in Crohn's disease

PURPOSE

Evaluation of mesenteric transit time (MTT) - measured by contrast-enhanced ultrasound - as a marker for inflammatory activity in Crohn's disease.

MATERIALS AND METHODS

The time of maximum enhancement of the contrast agent in the superior mesenteric artery and vein was determined visually and by software analysis. The MTT was calculated as the difference between these two time points. Findings were correlated with the Harvey-Bradshaw Index (HBI) using the Pearson correlation coefficient (r). In addition, a healthy control group was evaluated both in the fasting state and 1, 2, 3 and 4 hours postprandially.

RESULTS

In 20 healthy controls the mean visual MTT during fasting was 9.76 ± 2.83 sec and decreased to a minimum 1 hour after the meal (6.6 ± 2.27 sec). 45 patients with Crohn's disease (9 males, 36 females, mean age 35 years) had a mean HBI of 5.9 ± 4.7 points. The mean software-based MTT of 9.76 ± 3.7 sec was significantly higher (p = 0.034) than the mean visual MTT of 8.22 ± 3.05 sec. The two figures correlated well (r = 0.72, p < 0.001). The HBI correlated neither with the visual (r = 0.14, p = 0.371) nor with the software-based (r = 0.16, p = 0.293) MTT.

CONCLUSION

The MTT decreases in the first two hours after eating. The visually assessed and the software-based MTT correlate well, however MTT does not correlate with disease activity in patients with Crohn's disease.

Performance of Acoustic Radiation Force Impulse imaging for the staging of liver fibrosis: a pooled meta-analysis

Acoustic Radiation Force Impulse (ARFI) imaging is a novel ultrasound-based elastography method that is integrated in a conventional ultrasound machine enabling the exact localization of measurement site. It might present an alternative method to transient elastography for the noninvasive assessment of liver fibrosis. At present, studies with small patient population have shown promising results. A systematic review and meta-analysis of pooled patient data were performed to evaluate the overall performance of ARFI for the staging of liver fibrosis. Literature databases were searched up to 10/2010. The authors of the original publication were contacted, and the original patient data were requested. A meta-analysis was performed using a random effect meta-analytic method for diagnostic tests. In addition, available data comparing ARFI with FibroScan with the DeLong test were evaluated. Literature search yielded nine full-paper publications evaluating ARFI while using liver biopsy as reference method. Original patient data were available from eight studies including 518 patients. The mean diagnostic accuracy of ARFI expressed as areas under ROC curves (AUROC) was 0.87 for the diagnosis of significant fibrosis (F ≥ 2), 0.91 for the diagnosis of severe fibrosis (F ≥ 3), and 0.93 for the diagnosis of cirrhosis. ARFI can be performed with good diagnostic accuracy for the noninvasive staging of liver fibrosis.

Frequency of tumor entities among liver tumors of unclear etiology initially detected by sonography in the noncirrhotic or cirrhotic livers of 1349 patients. Results of the DEGUM multicenter study

AIM

Investigation of the frequency of various solid focal liver lesions (SFLL) in noncirrhotic and cirrhotic livers with focus on the frequency of metastasis in cirrhotic livers.

MATERIAL AND METHODS

The patient collective in the DEGUM multicenter study (n = 1349) was reevaluated and divided in subcollective A without (n = 1067) and B with cirrhosis (n = 282). 74.6 % of the various tumor entities were confirmed histologically (n = 1006).

RESULTS

In subcollective A there were 385 patients with metastases (36.4 %) and 65 with HCC (6.1 %), whereas the most common benign lesions were hemangioma, with 237 cases (22.4 %) and FNH, with 170 cases (16.1 %). In subcollective B there were 216 cases of HCC (76.6 %) and 12 metastases (4.3 %), as well as 42 benign lesions (14.9 %). CCC was rare in both subcollective A (3.3 %) and subcollective B (2.5 %). A positive oncological history increased the probability of a malignant SFLL in subcollective A by 1.8 times, but did not do so in subcollective B.

CONCLUSION

The frequency of various tumor entities is different in patients with and without cirrhosis of the liver. In noncirrhotic livers, malignant and benign SFLL are equally common. The most common forms are metastases, hemangiomas and FNH, CCC is rare. A positive history of extrahepatic malignancy increases the probability of a malignant SFLL. In cirrhosis, HCC dominates, HCC is 18 times as common as metastases. Benign SFLL and CCC are rare.

Diagnostic accuracy of CEUS in the differential diagnosis of small (≤ 20 mm) and subcentimetric (≤ 10 mm) focal liver lesions in comparison with histology. Results of the DEGUM multicenter trial

PURPOSE

To evaluate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of small and subcentimetric liver tumors in clinical practice.

MATERIALS AND METHODS

1349 patients with a hepatic tumor lacking a definite diagnosis based on B-mode ultrasound and power Doppler ultrasound were examined at 14 hospitals by CEUS using a standardized protocol (pulse/phase inversion imaging, mechanical index < 0.4). Differential diagnosis was based on the vascularity pattern and contrast enhancement pattern during the arterial, portal, and late phase according to the EFSUMB guidelines. 335 patients with focal liver lesions (FLL) ≤ 20  mm were analyzed. The tumor status established after CEUS was compared to histology (73.2 %) or in some cases to CT or MRI.

RESULTS

A definitive diagnosis based on the gold standard was possible in 329 FLLs, while 6 FLLs remained unclear even in the combined gold standard (histology and/or CT and/or MRI). The final diagnoses of ≤ 20  mm FLL with histological confirmation (n = 241) included 87 benign and 154 malignant entities. The overall diagnostic accuracy of CEUS in FLL ≤ 20  mm with histological confirmation was 83.8 %. CEUS correctly identified 144 /154 malignant FLLs (sensitivity 93.5 %) and 58 /87 benign FLLs (specificity 66.7 %). 24 /241 FLLs remained unclear after CEUS (9.9 %). CEUS misclassified 15 /241 FLLs (6.2 %; 12 benign and 3 malignant FLLs). The positive predictive value of CEUS for a malignant FLL was 92.3 % and the negative predictive value was 95.1 %. Out of 241 small FLLs with histological confirmation, 62  FLLs were ≤ 10  mm (diagnostic accuracy of CEUS 80.6 %) and 179 FLLs were > 10  mm and ≤ 20  mm (diagnostic accuracy of CEUS 84.9 %).

CONCLUSION

CEUS has a high diagnostic accuracy for the differential diagnosis of small and subcentimetric FLLs in clinical practice.

Efficacy of contrast-enhanced US versus CT or MRI for the therapeutic control of percutaneous radiofrequency ablation in the case of hepatic malignancies

PURPOSE

The goal of this study was to assess the informative value of contrast-enhanced ultrasound after radiofrequency ablation (RFA). Patients who had undergone RFA of malignant liver tumors were followed up with contrast-enhanced sonography (CEUS), computed tomography (CT) and/or magnetic resonance tomography (MRI), and the outcomes were compared.

MATERIALS AND METHODS

76 patients undergoing 194 RFAs for 118 hepatic neoplasms (n = 55 HCC, n = 63 metastases) in the course of a 7-year period were examined post-interventionally using CEUS and CT or MRI. During follow-up (gold standard of evaluation), contrast agent rim accumulations with a diameter greater than 5 mm and a growth rate of at least 25 % were counted as a recurrence.

RESULTS

CEUS-CT comparison group: A total of 65 scan pairs were compared. In 54 cases (83.1 %) the findings were the same with either method. In 7 cases (10.8 %) CEUS confirmed the correct diagnosis, and in 2 cases (3.1 %) only CT was correct. In 2 cases (3.1 %) both methods yielded incorrect results. Diagnostic accuracy (DA): CEUS 93.8 %, CT 86.2 %. CEUS-MRI comparison group: In 23 cases (88.5 %) of a total of 26 scan pairs, the findings were the same for both CEUS and MRI. In 3 discordant cases only CEUS confirmed the correct diagnosis (3 cases, 11.5 %). Diagnostic accuracy DA (n = 26): CEUS 100 %, MRI 88.4 %.

CONCLUSION

CEUS performs equally to CT and MRI in the follow-up of patients treated for liver tumors by RFA.

[A comparative study of the hepatic transit time (HTT) of different ultrasound contrast agents in patients with liver metastases and healthy controls]

PURPOSE

Liver metastases lead to a shortening of the HTT of an echo enhancer. Studies using SonoVue™ also showed a shortening of the HTT in healthy controls. Hence the HTT depends on the applied contrast agent. We examined whether the HTT of SonoVue™, Luminity™ und Levovist™ is useful to discriminate between patients with and without liver metastases.

MATERIALS AND METHODS

We compared the arteriovenous HTT of Levovist™, Sonovue™ und Luminity™ in 20 patients with liver metastases and in 15 controls. An Acuson Sequoia™ ultrasound system was used. The HTT results from the difference of the arrival time of the microbubbles in the hepatic artery and a hepatic vein.

RESULTS

Using Levovist™ six patients and three controls had to be excluded from further analysis. The arrival time was undetectable. The mean HTT values in healthy controls were: Levovsit™ 14.75 sec (SD ± 2.53 sec), SonoVue™ 9.27 sec (SD ± 2.41 sec) and Luminity™ 9.2 sec (SD ± 2.34 sec). In patients the mean HTT values were: Levovist™ 9.89 sec (SD ± 1.04 sec), SonoVue™ 6.28 sec (SD ± 2.41 sec) and Luminity™ 6.33 sec (SD ± 1.37 sec). Using a cut off of 8 sec for SonoVue™ and Luminity™, the sensitivity to exclude liver metastases was 75% and 80%.

CONCLUSION

The mean HTT values of all contrast agents were shorter in patients. Levovist™ showed a longer HTT in patients and controls than Luminity™ and SonoVue™. Levovist™ showed the best separation between patients and controls but some patients and controls had to be excluded. The HTT could still be a useful tool to exclude liver metastases but the HTT depends on the contrast agent and the applied contrast technique.

Unclear focal liver lesions in contrast-enhanced ultrasonography--lessons to be learned from the DEGUM multicenter study for the characterization of liver tumors

PURPOSE

To discuss the difficulties of contrast-enhanced ultrasound (CEUS) in a large multi-center trial.

MATERIALS AND METHODS

CEUS was performed on 1349 liver lesions with an unclear diagnosis after native ultrasound using a standardized protocol (phase inversion; low MI < 0.4; Sonovue Bolus 1.2 - 4.8 ml). The early arterial, arterial, portal venous and late phase > 2 min. were documented. The diagnosis based on CEUS results was compared to the final diagnosis (histology: n = 1006; MRI: n = 269; CT: n = 269 - multiple examinations possible).

RESULTS

Of the 1349 enclosed liver lesions, 20 could not be definitively diagnosed even using all diagnostic steps including histology (the others were proven to be benign n = 573 or malignant n = 756). Of the 1349 unclear liver lesions, 1257 could be differentiated with an accuracy of 90.3% using CEUS. The sensitivity, specificity, and positive and negative predictive value for malignant liver lesions was 95.8%, 83.1%, 88.2% and 93.7% respectively. 92 liver lesions (6.8%) could not be definitively diagnosed using CEUS. Most of them were benign (n = 67) on final diagnosis. The CEUS diagnosis was wrong for 39 lesions. However, only 8 lesions classified as benign by CEUS turned out to be malignant. In 3 cases HCC proven by histology was incorrectly diagnosed by CEUS as adenoma and 2 lesions incorrectly diagnosed by CEUS as FNH turned out to be an HCC and a metastasis. Two lesions diagnosed by CEUS as hemangiomas turned out to be an HCC and a metastasis. One lesion classified as benign by CEUS was ultimately diagnosed as a lymphoma.

CONCLUSION

Even in this multi-center trial, CEUS proved to be an excellent method for clarifying liver lesions remaining unclear after native ultrasound. The CEUS diagnosis of benign was only incorrect in a few cases.

An abdominal and thyroid status with Acoustic Radiation Force Impulse Elastometry--a feasibility study: Acoustic Radiation Force Impulse Elastometry of human organs

PURPOSE

Acoustic Radiation Force Impulse (ARFI) is a new method for the quantification of tissue elasticity. To date, ARFI technology has not been applied systematically to establish an abdominal and thyroid status. The aim of this prospective feasibility study was to evaluate ARFI elastometry performed on various healthy abdominal organs and the thyroid gland.

MATERIAL AND METHODS

94 patients (43 females, 51 males) with a mean age of 54 years and 20 healthy controls were enrolled in the study. A routine ultrasound examination of the abdomen was scheduled in 72, and of the thyroid in 25. ARFI elastometry was performed in liver, spleen, pancreas, prostate, kidneys and thyroid gland with the ultrasound system Acuson S2000. ARFI values are proportional to tissue elasticity. Patients with ultrasonic or anamnestic evidence of diseased organs were excluded from the analysis. ARFI measurements were compared with the aid of the t-test and correlated using Spearman's correlation coefficient.

RESULTS

ARFI elastometry proved feasible and the measurements obtained in the various organs differed significantly. Among healthy organs the spleen showed the highest mean ARFI velocities, followed by the kidney, thyroid, pancreas and the prostate. The lowest ARFI values were regularly found in healthy liver. Measurements in the kidneys and the spleen showed high standard deviation.

CONCLUSIONS

ARFI elastometry may describe parenchymal stiffness of various abdominal organs and the thyroid gland. Further investigations are needed to compare these baseline findings in healthy organs with those of various tumours or diseases affecting the individual organs.

Contrast-enhanced ultrasound (CEUS) for the characterization of focal liver lesions in clinical practice (DEGUM Multicenter Trial): CEUS vs. MRI--a prospective comparison in 269 patients

PURPOSE

The aim of this prospective multicenter study was to assess the diagnostic role of CEUS in the diagnosis of newly discovered focal liver lesions in clinical practice. One important aspect is the comparison of CEUS with magnetic resonance imaging (MRI).

MATERIALS AND METHODS

From 05 / 2004 to 12 / 2006, standardized CEUS was performed prospectively on 1349 patients with focal liver lesions that had been newly detected by fundamental ultrasound in order to determine tumor differentiation and tumor entity. 269 patients had a standardized MRI after CEUS. In typical liver hemangioma and focal nodular hyperplasia (FNH), the definitive diagnosis was based on the MRI as the "diagnostic gold standard" and on clinical evidence and additional follow-up (subgroup A) or on histology (subgroup B). 262 patients met the diagnostic standard that had been set.

RESULTS

In the subcollective (n = 262), the tumor differentiation (malignant or benign) of CEUS and MRI was concordant in 225 cases (85.9%), and the assessment of tumor entity in 204 cases (77.9%). In subgroup A (n = 180), concordant results for tumor differentiation were obtained in 169 (93.2%) and for tumor entity in 160 (88.9%) cases. Liver hemangiomas (n = 122) and FNH (n = 43) were most frequent. Subgroup B (n = 82) comprised mainly malignant liver lesions (n = 55), with only a few of hemangiomas (n = 8) or FNH (n = 5). Tumor differentiation was concordant in 56 (68.3%) and tumor entity in 44 cases (53.7%). There were no statistically proven differences between CEUS and MRI.

CONCLUSION

CEUS and MRI are of equal value for the differentiation and specification of newly discovered liver tumors in clinical practice. CEUS and MRI are extremely reliable for the differentiation of benign and malignant lesions, the diagnosis of liver hemangiomas and FNH. The characterization of metastases and HCC is also very reliable.

Eosinophilic infiltration of the liver and pancreas mimicking metastatic disease

Contrast-enhanced ultrasound (CEUS) has significantly improved the differentiation of hepatic lesions and the detection of liver metastases. Metastases are usually represented as hypoenhanced areas in the late phase and must then be confirmed histologically. Other lesions presenting hypoenhancement in the late phase are abscesses, hepatocellular and cholangiocellular carcinomas, adenomas, avascular necrosis, haematomas and rarely inflammatory masses. The differentiation between these relies on the patient's history, the number of lesions presenting, the B-image morphology and the enhancement pattern in the early phase of CEUS. We report the case of a 49-year-old woman with a in CT assumed pancreatic tumour in whom liver metastases were suspected and investigated by CEUS. In the late phase of this examination hypoenhanced hepatic lesions were observed, prompting us to perform a needle biopsy. The histopathological work-up surprisingly identified the hepatic lesions to be eosinophilic infiltration. After a spontaneous remission we concluded an allergic reaction to a fluoroquinolone.

Characterization of focal liver lesions (FLL) with acoustic radiation force impulse (ARFI) elastometry

PURPOSE

The technology of acoustic radiation force impulse (ARFI) represents an innovative method for the quantification of tissue elasticity. The aim of this prospective pilot study was to evaluate the role of ARFI elastometry of focal liver lesions (FLL) and the surrounding liver parenchyma.

MATERIALS AND METHODS

All patients with unclear FLL in B-mode ultrasound were assigned to ARFI elastometry (m/sec). Measurement sites were located within the FLL, in the peritumoral tissue and in hepatic segment VIII (intercostal approach). Histology and CEUS served as the reference for the characterization of the lesions.

RESULTS

A total of 81 patients were enrolled, of whom 62 patients (39 females, 23 males; mean age 54 years) had FLL measurable by means of ARFI. The lesions were: 38 benign (61 %) and 24 malignant FLL (39 %). The ARFI elastometric values of the FLL differed significantly from those of the liver parenchyma (p < 0.001). Elastometry of benign lesions and of malignant tumors showed statistically comparable results (p = 0.28). The lowest ARFI values were observed in focal fatty sparing and the highest in CCC. Only focal fatty sparing and HCC showed negative differences between FLL and peritumoral tissue or liver parenchyma. In 23 % of the hepatic lesions, no reliable quantitative ARFI results were obtainable due to false, inconsistent or technically failed measurements.

CONCLUSION

FLL vary in ARFI elastometry. However, high ARFI values occur in benign as well as in malignant lesions and do not permit differentiation between them.

Measurement of liver elasticity with acoustic radiation force impulse (ARFI) technology: an alternative noninvasive method for staging liver fibrosis in viral hepatitis

PURPOSE

The acoustic radiation force impulse (ARFI) technology is a novel ultrasound method that provides information about the local elasticity of tissue in real-time. ARFI is integrated in a conventional ultrasound system. The aim of this exploratory study was to evaluate this new technique in the assessment of liver fibrosis in a cohort with chronic viral hepatitis B and C and to ascertain the most reliable hepatic segment for measurements.

MATERIALS AND METHODS

57 patients (27 female, 30 male, mean age 54 years) with chronic viral hepatitis B and C underwent ARFI imaging and consecutively liver biopsy. The results were compared to the histological fibrosis degree (F), which served as the reference. 20 healthy volunteers received ARFI quantification of different segments of the liver.

RESULTS

The best ARFI assessments with the lowest rate of invalid measurements were carried out by an intercostal approach to segment VII/VIII of the liver. The ARFI velocities of the healthy group had a mean of 1.09 m/s (range 0.79 - 1.32 m/s), the means of the patient group ranged from 0.83 to 4.19 m/s. ARFI quantification correlated significantly with the histological fibrosis stage (p < 0.001). The area under the receiver operating characteristic (ROC) curves for the accuracy of ARFI imaging was 85 %, 92 % and 87 % for the diagnosis of moderate fibrosis (>or= F2), severe fibrosis (>or= F3) and cirrhosis ( = F 4), respectively.

CONCLUSION

This study underscores the usefulness of ARFI as a quick method for assessing liver fibrosis or cirrhosis in patients with HBV or HCV. ARFI measurements of the liver should be performed via an intercostal access. Increasing ARFI velocities correlate with higher degree of hepatic fibrosis.

Tumor-specific vascularization pattern of liver metastasis, hepatocellular carcinoma, hemangioma and focal nodular hyperplasia in the differential diagnosis of 1,349 liver lesions in contrast-enhanced ultrasound (CEUS)

AIM

To evaluate the incidence and diagnostic accuracy of tumor-specific vascularization pattern in contrast-enhanced ultrasound (CEUS) in the differential diagnosis of liver tumors in clinical practice.

MATERIALS AND METHODS

From May 2004 to December 2006 1349 patients (male 677, female 672) with a hepatic tumor lacking a definite diagnosis based on B-mode ultrasound and power Doppler ultrasound were examined at 14 hospitals by CEUS using a standardized protocol (pulse/phase inversion imaging, mechanical index < 0.4). Vascularity pattern and contrast enhancement pattern were analyzed in focal lesions during the arterial, portal, and late phase. The tumor-specific diagnosis established after CEUS was compared to histology (> 75 % cases) or in some cases to CT or MRI.

RESULTS

The final diagnosis of 573 benign hepatic tumors included hemangiomas (n = 242) and focal nodular hyperplasia (n = 170), other benign lesions (n = 161). Tumor-specific vascularization pattern such as a wheel-spoke pattern and arterial hyperenhancement followed by isoenhancement in the late phase in FNH or a nodular peripheral enhancement and partial or complete fill-in pattern in hemangiomas could be assessed in the majority, but not all lesions. The diagnostic accuracy of CEUS was 83.1 % for all benign lesions and 82.2 % for hemangioma and 87.1 % for FNH. The final diagnosis of 755 malignant hepatic tumors included metastases n = 383, hepatocellular carcinoma n = 279 and other malignant lesions n = 93. Late phase hypoenhancement was seen in almost all liver metastases (94.7 %) The diagnostic accuracy of CEUS was 95.8 % for all malignant lesions and 91.4 % for liver metastases and 84.9 % for hepatocellular carcinomas.

CONCLUSION

Tumor-specific vascularization pattern in CEUS have a high diagnostic impact on the overall high diagnostic accuracy of CEUS for the differential diagnosis of hepatic tumors in clinical practice.

Contrast-Enhanced Ultrasound (CEUS) for the characterization of focal liver lesions - prospective comparison in clinical practice: CEUS vs. CT (DEGUM multicenter trial). Parts of this manuscript were presented at the Ultrasound Dreiländertreffen 2008, Davos

AIM

The aim of our study was to evaluate the diagnostic value of Contrast-Enhanced Ultrasound (CEUS) for the characterization of focal liver lesions in a prospective multi-center study in clinical practice. For this purpose CEUS was compared with the spiral-CT (SCT), the standard radiological method.

MATERIAL AND METHODS

1349 patients with unclear liver lesions after fundamental ultrasound diagnostics including color doppler analysis were examined with standardized CEUS (pulse inversion method, mechanical index < 0.4) from May 2004 to December 2006 in 14 hospitals in a prospective study. The enhancement of contrast medium in the liver tumors was analyzed according to known tumor-specific vascular patterns, using standardized documentation and analysis methods for the differentiation of tumor differentiation (malign or benign) and tumor specification (entity). A subcollective of 267 patients was additionally examined by standardized SCT method. Final diagnosis was based on histology, SCT or MRI in typical findings of liver hemangioma and FNH and on proved clinical data and additional follow up.

RESULTS

The subcollective of 267 patients was divided in two subgroups. In 109 of these patients (subgroup A) there was no histological verification, diagnoses based on clear SCT-findings in 79 cases of hemangioma or FNH, as well as in 20 cases with a clear clinical diagnosis. 6 cases (5.5 %) remained unclear. In this subgroup the assessment of tumor differentiation was concordant with CEUS in 90 cases, discordant in 19 cases and the assessment of tumor specification was concordant in 82 and and discordant in 27 cases. In 158 patients (subgroup B) a histological finding was also present, only in 4 cases no definitive tumor diagnosis was achieved. In this subgroup assessment of tumor differentiation with CEUS and SCT was concordant in 124 cases and discordant in 30 cases (CEUS/SCT: sensitivity 94.0 / 90.7 %, specificity 83.0 / 81.5 %, PPV 91.6 / 91.5 %, NPV 87.5 / 80.0 %, accuracy 90.3 / 87.8 %). Tumor specification matched in 103cases and were different in 51 cases (CEUS/SCT: sensitivity 95.3 / 90.6 %, specificity 83.7 / 81.6 %, PPV 92.7 / 91.4 %, NPV 89.1 / 80.0 %, accuracy 91.6 / 87.7 %). A statistically significant difference could not be established. The analysis of particular tumor specification showed a statistically non significant slight advantage in tumor differentiation for CEUS in the case of hemangioma, FNH, HCC and metastases.

CONCLUSION

In a multi-center approach under routine clinical conditions, this prospective study demonstrates CEUS to be of equal rank to the CT-scan in regard to the assessment of tumor differentiation and specification. No statistically significant differences could be established. CEUS should be employed before computed tomography is performed for the differentiation of liver tumors, because radiation exposure and invasive biopsies can be avoided in veritable numbers of cases, when precise clinical evaluation of the findings is implemented.