Characterization Of Liver Lesions Research Articles

Role of contrast-enhanced ultrasound in the blinded assessment of focal liver lesions in comparison with MDCT and CEMRI: Results from a multicentre clinical trial

The main aim of this multicentre prospective study was to determine the clinical value of SonoVue ® administration for the characterisation of focal liver lesions incidentally detected in oncological or cirrhotic patients. Eight hundred and seventy four consecutive patients with 1034 nodules (diameter between 5 and 100 mm) not fully characterised by conventional US or previous single-phase CT-scan were imaged using real-time contrast-enhanced scanning after intravenous injection of 2.4 ml of SonoVue ® Blinded off-site assessment was conducted to evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) in comparison with gold standard, i.e. triphasic CT-scan or contrast-enhanced MRI or histology. In the differentiation between benign and malignant lesions, CEUS yielded a sensitivity of 79.4% and a specificity of 88.1%. In the subgroup of patients with cirrhosis, the kappa value for off-site diagnosis between CEUS and reference modality was slightly lower compared to the non-cirrhotic group: 0.42 and 0.66 ( p = 0.0002), respectively. The concordance rate and kappa value of CEUS for benign to malignant differentiation between on-site and blinded review were 90.2% and 0.80%, respectively, compared to 83.4% and 0.66%, respectively, for the reference imaging technique. These results indicate that CEUS using SonoVue ® is a competitive and effective diagnostic tool for the characterisation of focal liver lesions compared to other modalities such as CT and MR imaging.

Detection and characterization of focal hepatic lesions: comparative study of MDCT and gadobenate dimeglumine-enhanced MR imaging

The aim of this study was to compare the diagnostic performance of multidetector row helical CT (MDCT) and gadobenate dimeglumine-enhanced magnetic resonance (MR) imaging (in the detection and characterization of focal liver lesions. Two blind reviewers analyzed the MDCT and MR images of a total of 44 malignant and 85 benign lesions in 46 patients independently. Receiver operating characteristic curves were established to analyze the results for each reviewer and modality.

The EFSUMB guidelines for contrast-enhanced ultrasound are comprehensive and informative for good clinical practice: will radiologists take the lead?

A study group organized by the European Federation of Societies of Ultrasound in Medicine and Biology (EFSUMB) has issued an up-to-date set of guidelines on the clinical application of contrast-enhanced ultrasound (CEUS) [1]. The first set of guidelines for the application of contrast agents to the practice of ultrasound were published in 2004 [2], and the present set of guidelines are directed towards those not intimately involved in the field, whose perception is that rapid advances in technology and techniques can be difficult to follow, as well as experienced users of CEUS. The initial guidelines concentrated on CEUS applications in the liver, but the present guidelines recognize the expanding role of CEUS and include recommendations for its use in (i) the kidney, (ii) vesicoureteric reflux, (iii) the pancreas, (iv) trauma and (v) the cerebral circulation. The guidelines include good clinical practice recommendations for the use of CEUS, and are exceptionally comprehensive without being lengthy. Detailed descriptions of the procedure techniques, the interpretation of findings and its limitations are included. The study group readily acknowledge the shortcomings of a CEUS examination; these are the exact limitations that occur with all ultrasound examinations. When the baseline ultrasound examination is disappointing, then the CEUS examination is also likely to disappoint — an important caveat for those incorporating techniques of CEUS into their practice. Recommendations for investigator training are also included, with the likelihood that practitioners of CEUS would need to have attained at least a Level 2 of competency, if not higher. Currently, there are four agents licensed for use in Europe: Levovist (Schering, Berlin, Germany), Optison (GE Healthcare, Oslo, Norway), Definity (BristolMeyers Squibb, Uxbridge, UK) and SonoVue (Bracco, Milan, Italy).The sole indication to date for Optison and Luminity is for cardiac use. Practitioners in Japan have the advantage of access to another agent: Sonazoid (GE Healthcare, Oslo, Norway). Levovist, the oldest agent (having been introduced in 1996), is not sufficiently robust to be used adequately with the newer low mechanical index (MI) techniques. It does, however, have the characteristic of late phase ‘‘trapping’’ in the liver, a feature not demonstrated by some of the newer agents (except for Sonazoid) but which has been exploited to good effect in the past [3]. Current recommendations do not promote the use of high MI techniques to investigate liver lesions in the late phase, citing technical difficulties [1]. As a consequence, the most widely used agent currently for radiological indications in Europe is SonoVue This agent is particularly suited for the low MI techniques for the detection and characterization of focal liver lesions, with studies indicating that CEUS is as good, if not better, than contrast-enhanced CT [4, 5]. With CEUS, a ‘‘black hole’’ at the end of the portal venous phase almost always indicates a secondary malignant lesion (if a cyst has been excluded on the baseline examination) [1]. The usefulness of CEUS is not in doubt. Many new applications outside the traditional investigation of parenchymal liver lesions have developed or are evolving, with assessment of blunt abdominal trauma in the emergency room being particularly attractive [6]. The establishment of a standard CEUS ‘‘Bosniak’’ classification of renal cysts is also a possibility [7]. The list of useful applications grows as more investigators report their findings; however, the technique has not been fully embraced by the radiological community, despite the proven usefulness of CEUS. Uptake is slow, particularly in the UK, although ‘‘hot spots’’ exist. The European radiological community shows more interest in the use of CEUS, particularly in Italy. Japan and China are driving clinical practice with CEUS. However, there is a Address correspondence to: Paul S Sidhu, Department of Radiology, King’s College Hospital, Denmark Hill, London SE5 9RS, UK. E-mail: paul.sidhu@kch.nhs.uk The British Journal of Radiology, 81 (2008), 524–525

Detection and characterization of liver lesions in patients with colorectal cancer with diffusion weighted MR imaging

4071 Background: In patients with colorectal cancer detection and differentiation of liver metastases is important for further treatment decissions. Recently diffusion weighted MR imaging (DWI) was introduced as an new technique for liver tumor detection and characterzation. DWI is sensitive to molecular diffusion which is the random thermal motion of molecules (Brownian motion). MR imaging is the only method by which molecular diffusion processes can be evaluated in vivo. New techniques, such as breath-hold imaging or respiratory triggered single shot echo-planar-imaging (EPI) allow to extent DWI to abdominal organs, especially the liver. First results show that DWI can be used for the reliable detection of small subcentimeter liver lesions. We evaluated this new imaging method with regard to liver lesion detection and lesion characterization in patients with colorectal cancer. Methods: 115 consecutive patients with colorectal cancer and suspected liver metastases were evaluated with multi slice-CT and MRI at 1.5 Tesla using T1- and T2-weighted pulse sequences as well as DWI with respiratory triggered single shot echo-planar-imaging (EPI). Images were analyzed by two experienced radiologist blinded to the clinical results. Results for lesion detection for CT and DWI-MRI were compared using ROC analysis. Furthermore, in a subset of 60 patients diffusion coefficients (ADCs) were calculated for the differentiation of liver lesions (benign vs malignant). Results: For lesion detection ROC analysis showed superiority (p< 0.05) of DWI as compared to MS-CT. Especially metastases with diameters of smaller 1 cm were better detected with DWI-MRI as compared to MS-CT (p < 0.02). Results for differentiation show mean ADC-values of 1.24 for normal liver while malignant tumors have ADCs of 1.04–1.22 and benign lesions such as hemangiomas or cysts of 1.9 to 3.0, respectively. Furthermore, therapeutic changes were made in 20 % of patients based on DWI. Conclusions: MR imaging using DWI is more sensitive than multi- detector row CT in the detection and characterization of liver metatstases from colorectal cancer. Thus, it can be used as a new method for liver lesion detection and characterization as well as for optimal treatment planning. No significant financial relationships to disclose.

The role of contrast-enhanced ultrasound in the characterisation of focal liver lesions

Introduction: Contrast-enhanced sonography is a useful tool for evaluating the vascularity of liver tumors, because it allows visualization of the blood perfusion. Moreover, the method is simple, easy, and minimal invasive, being usually performed on an out-patient basis.

Dynamische MRT der Leber mit paralleler Akquisitionstechnik: Charakterisierung fokaler Leberläsionen und Analyse des Gefäßstatus in einem Untersuchungsgang

To retrospectively evaluate the performance of breath-hold contrast-enhanced 3D dynamic parallel gradient echo MRI (pMRT) for the characterization of focal liver lesions (standard of reference: histology) and for the analysis of hepatic vasculature (standard of reference: contrast-enhanced 64-detector row computed tomography; MSCT) in a single MRI session. Two blinded readers independently analyzed preoperative pMRT data sets (1.5T-MRT) of 45 patients (23 men, 22 women; 28 - 77 years, average age, 48 years) with a total of 68 focal liver lesions with regard to image quality of hepatic arteries, portal and hepatic veins, presence of variant anatomy of the hepatic vasculature, as well as presence of portal vein thrombosis and hemodynamically significant arterial stenosis. In addition, both readers were asked to identify and characterize focal liver lesions. Imaging parameters of pMRT were: TR/TE/matrix/slice thickness/acquisition time: 3.1 ms/ 1.4 ms/ 384 x 224 / 4 mm/ 15 - 17 s. MSCT was performed with a pitch of 1.2, an effective slice thickness of 1 mm and a matrix of 512 x 512. Based on histology, the 68 liver lesions were found to be 42 hepatocellular carcinomas (HCC), 20 metastases, 3 cholangiocellular carcinomas (CCC) as well as 1 dysplastic nodule, 1 focal nodular hyperplasia (FNH) and 1 atypical hemangioma. Overall, the diagnostic accuracy was high for both readers (91 - 100 %) in the characterization of these focal liver lesions with an excellent interobserver agreement (kappa-values of 0.89 [metastases], 0.97 [HCC] and 1 [CCC]). On average, the image quality of all vessels under consideration was rated good or excellent in 89 % (reader 1) and 90 % (reader 2). Anatomical variants of the hepatic arteries, hepatic veins and portal vein as well as thrombosis of the portal vein were reliably detected by pMRT. Significant arterial stenosis was found with a sensitivity between 86 % and 100 % and an excellent interobserver agreement (kappa = 0.85). Diagnostic image quality remains good or excellent in most cases when the data acquisition time is accelerated by means of parallel imaging in dynamic MRI. It allows reliable detection and characterization of focal liver lesions as well as the depiction of hepatic vascular variants, portal vein thrombosis, and arterial stenosis. Introducing pMRT in routine liver MRI may be another step towards a simplified diagnostic work-up prior to liver surgery.

Detection and characterization of focal liver lesions with contrast-enhanced ultrasonography in patients with hepatitis c-induced liver cirrhosis

Hepatitis C virus (HCV)-associated liver cirrhosis provides a major preneoplastic condition for hepatocellular carcinoma (HCC). Ultrasonography (US) is usually used for screening of HCC, but needs improvement. To assess whether use of a second-generation ultrasound contrast agent can improve characterization of focal liver lesions and detection of HCC in HCV-infected patients with liver cirrhosis. In total, 96 US studies in 49 HCV-infected patients with liver cirrhosis were performed. The patients were first examined with a baseline US. After this, a diagnostic decision was made and recorded. The patients were then re-examined with contrast-enhanced ultrasound (CEUS), and the diagnostic triage was repeated. The patients were followed up for at least 1 year. On baseline US, indeterminate focal lesions were found in 27 examinations. After CEUS, a confident diagnosis of HCC was made in eight of these examinations. In an additional eight US examinations, diagnosis of regenerative/dysplastic noduli was established. In one patient with no detectable focal lesion at baseline examination, an indeterminate malignant lesion was detected with CEUS. This lesion was further investigated with computed tomography and diagnosed as HCC. Our study indicates that the use of CEUS significantly improves diagnostic confidence. CEUS improves the detection of HCC in patients with HCV-induced liver cirrhosis. Also, CEUS makes it possible to rule out malignancy in many cases where baseline US shows indeterminate focal lesions. In low-endemic countries, the use of CEUS in screening for HCC may be considered.

Molecular Imaging and Ultrasound-Assisted Drug Delivery

Ultrasound imaging is undergoing a major revolution, about to bring this modality well beyond its established role as a low-cost noninvasive real-time imaging modality. Particularly important has been the commercial availability of microbubble-based contrast agents. Several new indications for contrast ultrasound have been developed and have entered clinical practice. The characterization of focal liver lesions and the follow-up of antiangiogenic therapy are two applications that will have a major impact in medical practice. Others, such as prostate cancer diagnosis, are still under investigation and need to be clinically validated. Thanks to its outstanding sensitivity, contrast-enhanced ultrasound is also geared to become the preferred modality for molecular imaging of diseases occurring at the vascular level. Angiogenesis, inflammation, and other endothelial dysfunctions are important targets that can be imaged and investigated with targeted microbubbles. In the field of prostate cancer, targeted agents will facilitate detection and provide additional information on tumor size, and hopefully on aggressiveness as well. Ultrasound can also play a role to deliver drugs or genes locally. This is an exciting area that has become an important field of research. Imaging and drug delivery can be performed simultaneously, thereby achieving the release of a drug, at the site where it is needed, in a most efficient way.

The role of Doppler Perfusion Index as screening test in the characterization of focal liver lesions

Purpose Doppler Perfusion Index (DPI) has been used in the detection of overt liver metastatic disease. In the present prospective study we evaluated the use of DPI in the differential diagnosis of liver tumours. Materials and methods We have included in our study 76 patients with focal hepatic lesion and 39 subjects as control group. All patients were evaluated by Color Doppler Ultrasound, and/or Spiral Computerised Tomography, Magnetic Resonance Imaging and biopsy. The radiologist performed DPI measurements was blind from the final diagnosis of the other methods. Results DPI measurements in the control group ranged from 0.07 to 0.22 (mean value 0.14), in 42 cases with benign lesions (group A) ranged from 0.05 to 0.53 (mean 0.15) and in 34 cases with malignant lesions (group B) ranged from 0.39 to 0.75 (mean 0.53). There was a statistically significant difference in DPI measurements between the control group and group B. Conclusions Our results suggest that the DPI may differentiate malignant from benign focal hepatic lesions and therefore can be used as a screening test in the routine clinical practice.

Physicochemical Characteristics of Sonazoid™, A New Contrast Agent for Ultrasound Imaging

The objective of the current work is to describe the physicochemical characteristics of Sonazoid™, a new ultrasound contrast agent for detection and characterisation of focal liver lesions. It has been demonstrated that Sonazoid™ powder for injection consists of microspheres of perfluorobutane (PFB) stabilised by a monomolecular membrane of hydrogenated egg phosphatidyl serine, embedded in an amorphous sucrose structure. Upon reconstitution with sterile water, stabilised microspheres of PFB are released in a predefined amount and size into a low viscosity, isotonic sucrose solution with a neutral pH. Sonazoid™ reconstituted product contains approximately 8 μl microspheres/ml with volume median diameter of approximately 2.6 μm. The product contains approximately 1.2 billion microspheres/ml of which less than 0.1% are larger than 7 μm. The acoustic properties of Sonazoid™ such as attenuation efficacy, fundamental and second harmonic backscatter efficacy are all well correlated to the microsphere volume concentration. The stability of Sonazoid™ after reconstitution is good, with no significant changes in physicochemical properties 2 h after reconstitution. Pressure stress is well tolerated by both concentrated and diluted Sonazoid™ with no permanent effects of pressures up to 300 mm Hg. The level and consistency of the investigated physicochemical properties demonstrate that Sonazoid™ should be well suited as a contrast agent for medical imaging with ultrasound. (E-mail: per.sontum@ge.com)

Focal Liver Lesion Detection and Characterization with Diffusion-weighted MR Imaging: Comparison with Standard Breath-hold T2-weighted Imaging

To retrospectively compare diffusion-weighted (DW) magnetic resonance (MR) imaging with standard breath-hold T2-weighted MR imaging for focal liver lesion (FLL) detection and characterization, by using consensus evaluation and other findings as the reference standard. Approval for this retrospective HIPAA-compliant study was obtained from the institutional review board; informed consent was waived. Fifty-three consecutive patients (30 men, 23 women; mean age, 60.7 years) with at least one FLL of 1 cm or greater in diameter were evaluated. Two independent observers reviewed DW (b values of 0, 50, and 500 sec/mm(2)) and T2-weighted images for FLL detection and characterization. Reference standard for diagnosis was obtained from consensus review by the two observers of DW, T2-weighted, and dynamic contrast material-enhanced images, pathologic data, and follow-up imaging results. Apparent diffusion coefficient (ADC) was measured for FLLs identified at consensus review. DW and T2-weighted images were compared for FLL detection and characterization by using a binary logistic regression model. Receiver operating characteristic curve analyses were conducted to evaluate the utility of ADC for diagnosis of malignancy. Two hundred eleven FLLs (136 malignant, 75 benign) were detected at consensus review. Overall detection rate (averaged for two observers) was significantly higher for DW (87.7%) versus T2-weighted (70.1%) imaging (P < .001). FLL characterization was not significantly different between DW (89.1%) and T2-weighted (86.8%) imaging (P = .51). ADCs of malignant FLLs were significantly lower than those of benign FLLs (P < .001). The area under the curve for diagnosis of malignancy was 0.839, with sensitivity of 74.2%, specificity of 77.3%, positive predictive value of 85.5%, negative predictive value of 62.3%, and accuracy of 75.3%, by using a threshold ADC of less than 1.60 x 10(-3) mm(2)/sec. DW MR imaging was better than standard breath-hold T2-weighted imaging for FLL detection and was equal to breath-hold T2-weighted imaging for FLL characterization.

Modern Liver MR Imaging Contrast Agents

SummaryMR Imaging has revealed high performance for focal liver lesion detection and characterization during a single examination procedure. Liver‐specific contrast media have shown to further increase the detection rate. The first liver‐specific contrast media approved where not injected as a bolus avoiding the acquisition of early dynamic sequences. The recently approved gadolinium‐based agent gadoxetic acid is offering for the first time a combination of an excellent and extracellular space contrast medium‐equivalent safety profile, a high diagnostic accuracy in lesion detection and characterisation by a highly liver‐specific uptake.

Multimodal imaging for the detection and characterization of liver lesions in a mouse model of neuroendocrine tumor

Background The aim of this study was to compare in vivo magnetic resonance imaging (MRI) and ex vivo autoradiography with histopathological results for the detection and characterization of liver lesions in an experimental model of human neuroendocrine tumors. Material and methods Intestinal STC-1 endocrine tumor cells were injected into 30 nude mice to achieve hepatic dissemination. Seven to 30 days after injection, T2-weighted in vivo images covering the entire liver were acquired with a 7-T system. Autoradiographs were also obtained in 28 mice after injection of fluorodeoxyglucose ( 18F-FDG). The autoradiographic liver samples were then stained with an antichromogranin antibody before histological analysis. Tumor size and the hepatic tumor fraction were measured using the three imaging modalities. Results Metastatic tumors visualized on the histological liver sections ranged in size from 50 μm (day 7) to 3 mm (day 30). The hepatic tumor fraction increased with time, reaching 30% of the hepatic surface area on day 30. Visual analysis revealed variable tumor distribution and type (solid and/or cystic). On MRI, lesions were identified from day 12 (about 100 μm in diameter) and the hepatic tumor fraction was up to 48% at day 30. The smallest lesions (350 μm in diameter) were also detected at day 12 on the autoradiographs. There was good correlation between tumor fractions determined from autoradiographic and histological data. Conclusion In vivo, MRI appears to be well suited to the follow-up of liver lesions in a mouse model of neuroendocrine tumor. Preliminary results using 18F-FDG in this animal model are promising, showing differences in FDG uptake.

Economic assessment of contrast-enhanced ultrasonography for evaluation of focal liver lesions: a multicentre Italian experience

The aim of this study was to evaluate the clinical and economic consequences of the introduction of contrast-enhanced ultrasonography (CEUS) into the diagnostic clinical algorithm for the characterization of incidental focal liver lesions (FLLs). This prospective study enrolled 485 subjects at three hospitals in Italy. Two diagnostic algorithms were utilized: (1) a classic patient work-up, which included baseline US followed by a CT or MR examination, and (2) a new patient management scheme in which, following the baseline US, a CEUS examination was performed. For each pathway, both direct and indirect health costs for the National Health System (NHS) at two of the three hospitals involved in the study were calculated. Clinical outcome was measured in terms of number of cases correctly diagnosed, using contrast-enhanced CT/contrast-enhanced MR as the reference standard. CEUS correctly differentiated (benign vs. malignant) 559 of 575 lesions (97.2%), with a sensitivity of 98.1% and a specificity of 95.7%. Histological characterization was correct in 502 of 575 lesions (87%) with a sensitivity of 90.5% and a specificity of 85.4%. In terms of cost, the conventional diagnostic algorithm incurred for the NHS a total cost of Euro 134.576,60 vs. Euro 55.674,30 with CEUS, for a saving of Euro 78.902 (Euro 162 per patient). For the hospitals, the total cost was Euro 147.045 without CEUS vs Euro 61.979 with CEUS, for a saving of Euro 85.065,96 or Euro 175,39 per patient. The routine use of CEUS for the characterization of FLLs provides significant cost savings, both for the NHS and for the hospital.

Clinical management of focal liver lesions: the key role of real-time contrast-enhanced US

Ultrasonography (US) is the most commonly used liver imaging modality worldwide. Unfortunately, it has limited sensitivity in the detection of small tumor nodules. Moreover, US findings are often nonspecific, as appearances of benign and malignant liver lesions overlap. The introduction of microbubble contrast agents and the development of contrast-specific techniques have opened new prospects in liver US. The advent of second-generation agents that enable continuous real-time contrast-enhanced imaging has been instrumental in improving the acceptance and reproducibility of the examination. With the publication of guidelines for the use of contrast agents in liver US by the European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB), contrast-enhanced US has entered clinical practice. The guidelines define the indications and recommendations for the use of contrast agents in focal liver lesion detection, characterization, and posttreatment follow-up. Recently, the clinical value of contrast US as a reliable alternative to CT or MR imaging in characterizing hepatocellular carcinoma in cirrhosis has been endorsed by the practice guideline document issued by the American Association for the Study of Liver Diseases and the 2005 Monothematic Conference on Hepatocellular Carcinoma of the European Association for the Study of the Liver. In this article, the current role of contrast US in the diagnostic management of focal liver lesions is discussed with regard to the following clinical scenarios: (1) characterization of incidental findings; (2) diagnosis of hepatocellular carcinoma in patients with cirrhosis; and (3) identification of hepatic metastases in oncology patients; (4) guidance and monitoring of tumor ablation procedures.

Improved focal liver lesion detection: Comparison of single‐shot spin‐echo echo‐planar and superparamagnetic iron oxide (SPIO)‐enhanced MRI

To prospectively compare single-shot spin-echo echo-planar imaging (SSSE-EPI) using b = 0, 10, 150, and 400 seconds/mm(2) with standard MRI techniques after intravenous super paramagnetic iron oxide (SPIO) in the detection and characterization of focal liver lesions with focus on small (<10 mm) focal liver lesions. A total of 25 patients suspected for colorectal liver metastases were included. Number of detected lesions was evaluated. Image quality was compared between SSSE-EPI sequence and post-SPIO (fat-suppressed T1-weighted [T1w] gradient echo [GE], T2-weighted [T2w] turbo spin echo [TSE] and T2* GE) sequences using rank order statistic (RIDIT). Lesion characterization was performed for SSSE-EPI and for all remaining sequences pre- and post-SPIO. Reference standard comprised surgery, biopsy, and/or follow-up. Reference standard demonstrated 25 hemangiomas and 70 metastases. Best lesion detection respectively best image quality (P < 0.05) was achieved with SSSE-EPI (b = 10 seconds/mm(2)) post-SPIO T1w GE and T2w turbo spin echo. Lesion characterization using all sequences pre- and post-SPIO performed best for lesion characterization compared with SSSE-EPI. This preliminary study shows the potential of SSSE-EPI as a stand-alone sequence for the detection of liver hemangiomas and metastases when compared with SPIO-enhanced imaging. Sequences pre- and post-SPIO are needed for qualitative lesion characterization.

Characterization of focal liver lesions by ADC measurements using a respiratory triggered diffusion-weighted single-shot echo-planar MR imaging technique

The aim of this study was to determine apparent diffusion coefficients (ADCs) of focal liver lesions on the basis of a respiratory triggered diffusion-weighted single-shot echo-planar MR imaging sequence (DW-SS-EPI) and to evaluate whether ADC measurements can be used to characterize lesions. One hundred and two patients with focal liver lesions [11 hepatocellular carcinomas (HCC), 82 metastases, 4 focal nodular hyperplasias (FNH), 56 hemangiomas and 51 cysts; mean size, 16.6 mm; range 5-92 mm] were examined on a 1.5-T system using respiratory triggered DW-SS-EPI (b-values: 50, 300, 600 s/mm2). Results were correlated with histopathologic data and follow-up imaging. The ADCs of different lesion types were compared, and lesion discrimination using optimal thresholds for ADCs was evaluated. Mean ADCs (x10(-3)mm2/s) were 1.24 and 1.04 for normal and cirrhotic liver parenchyma and 1.05, 1.22, 1.40, 1.92 and 3.02 for HCCs, metastases, FNHs, hemangiomas and cysts, respectively. Mean ADCs differed significantly for all lesion types except for comparison of metastases with HCCs and FNHs. Overall, 88% of lesions were correctly classified as benign or malignant using a threshold value of 1.63 x 10(-3)mm2/s. Measurements of the ADCs of focal liver lesions on the basis of a respiratory triggered DW-SS-EPI sequence may constitute a useful supplementary method for lesion characterization.

The late phase of Contrat-Enhanced Ultrasonography (CEUS) and Magnetic Resonance (MRI) with hepatospecific contrast material (Gd-Bopta) in the characterization of focal liver lesions

The late phase of Contrat-Enhanced Ultrasonography (CEUS) and Magnetic Resonance (MRI) with hepatospecific contrast material (Gd-Bopta) in the characterization of focal liver lesions

Effectiveness of EUS in Liver Lesions of Unclear Etiology

Endoscopic ultrasound (EUS) has assumed an important role in the diagnosis and staging of malignant GI tumors over the past few decades. EUS has widespread applications in the imaging of the GI tract, but has not been comprehensively studied in characterizing liver lesions. This case report describes the application of EUS in one such case. Case: 24 yo male with hypoplastic kidneys s/p renal transplant × 2 (last being 7 years prior), chronic transplant nephropathy, and chronic pancreatitis presented with a 3-week history of epigastric pain. CT of abdomen without intravenous contrast (due to the patient's renal function) revealed a 3–4 cm mixed density lesion in the anterior segment of the right hepatic lobe which was biopsied under CT-guidance with aspiration of 10–15 ml of serosanguinous fluid. Biopsy cultures grew Enterococcus for which the patient was prescribed intravenous ampicillin/sulbactam for 6 weeks. The patient left the hospital AMA. Two weeks later, he returned to the hospital and underwent an MRI without contrast and a trans-abdominal ultrasound with equivocal findings. A repeat CT-guided biopsy was performed and revealed a bloody aspirate. EUS was performed and showed a 30 × 40 mm vascular structure in the right lobe of the liver with turbulent flow with a doppler characteristic of an arterial structure, consistent with an arterio-venous malformation. Four weeks later, the patient presented with sharp epigastric pain, melena, and icterus. Labs revealed a total bilirubin of 22.5 mg/dL and a significant decrease in hemoglobin (10 to 5.9 g/dL). An EGD revealed esophagitis. Side-view endoscopy (duodenoscope) demonstrated blood-tinged bile from the major papilla. Contrast injection revealed blood clots obstructing the CBD, which was cleared and stented with a 10-Fr 10 cm plastic stent. The cause of the upper GI bleed was determined to be hemobilia. Conclusions: This case report suggests the use of EUS as the imaging modality of choice for the liver prior to any therapeutic endeavor for patients who have contraindications for radiological contrast. Although scant information is available on the use of EUS as a primary imaging modality in cases such as these, this report suggests EUS may serve an important role in identifying liver lesions and preventing potential iatrogenic complications.

Contrast-enhanced ultrasonography in the characterization of benign focal liver lesions: activity-based cost analysis

The aim of this study was to perform a cost analysis of contrast-enhanced ultrasonography (CEUS) in the study of benign focal liver lesions (BFLL) with indeterminate appearance on ultrasonography (US). A decision model of patients with suspected BFLL on baseline US who subsequently underwent CEUS between 2002 and 2005 was constructed. We analysed the cost effectiveness of CEUS, considering whether or not computed tomography (CT) was necessary for the diagnosis. There were 398 patients with 213 angiomas, 41 focal nodular hyperplasias (FNH) and 154 pseudolesions (focal fatty sparing, focal fatty areas). Each patient underwent CEUS, and 98 of them were also studied by CT. All lesions were followed up. The cost of a single CEUS examination was 101.51 euros, and that of a single CT scan was 211.48 euros. For diagnosis of haemangiomas, we saved 1,406.97 euros in 2002, 5,315.22 euros in 2003, 10,317.78 euros in 2004 and 9,536.13 euros in 2005. For diagnosis of focal nodular hyperplasias, we saved 781.65 euros in 2003, 781.65 euros in 2004 and 1,406.97 euros in 2005. For diagnosis of pseudolesions, we saved 2,813.94 euros in 2002, 5,158.89 euros in 2003, 5,158.89 euros in 2004 and 4,220.91 euros in 2005. In the period 2002-2005, the introduction of CEUS allowed us to save a total of 47,055.33 euros in the diagnosis of benign focal hepatic liver lesions. This cost analysis shows that CEUS is the least expensive second-line modality after baseline US for the diagnosis of BFLL.