Stefano Crosara

Contrast-Enhanced Ultrasound of Focal Liver Lesions.

OBJECTIVE The purpose of this article is to discuss the use of contrast-enhanced ultra-sound (CEUS) in focal liver lesions. CONCLUSION Focal liver lesions are usually detected incidentally during abdominal ultrasound. The injection of microbubble ultrasound contrast agents improves the characterization of focal liver lesions that are indeterminate on conventional ultrasound. The use of CEUS is recommended in official guidelines and suggested as a second diagnostic step after ultrasound detection of indeterminate focal liver lesions to immediately establish the diagnosis, especially for benign liver lesions, such as hemangiomas, avoiding further and more expensive examinations.

Acoustic radiation force impulse of the liver

Acoustic radiation force impulse (ARFI) imaging is a new and promising ultrasound-based diagnostic technique that, evaluating the wave propagation speed, allows the assessment of the tissue stiffness. ARFI is implemented in the ultrasound scanner. By short-duration acoustic radiation forces (less than 1 ms), localized displacements are generated in a selected region of interest not requiring any external compression so reducing the operator dependency. The generated wave scan provides qualitative or quantitative (wave velocity values) responses. Several non-invasive methods for assessing the staging of fibrosis are used, in order to avoid liver biopsy. Liver function tests and transient elastography are non-invasive, sensitive and accurate tools for the assessment of liver fibrosis and for the discrimination between cirrhotic and non-cirrhotic liver. Many published studies analyse ARFI performance and feasibility in studying diffuse liver diseases and compare them to other diagnostic imaging modalities such as conventional ultrasonography and transient elastography. Solid focal liver lesions, both benign and malignant, are common findings during abdominal examinations. The accurate characterization and differential diagnosis are important aims of all the imaging modalities available today. Only few papers describe the application of ARFI technology in the study of solid focal liver lesions, with different results. In the present study, the existing literature, to the best of our knowledge, about ARFI application on diffuse and focal liver pathology has been evaluated and results and statistical analyses have been compared, bringing to the conclusion that ARFI can be used in the study of the liver with similar accuracy as transient elastography in diagnosing significant fibrosis or cirrhosis and has got some advantages in respect to transient elastography since it does not require separate equipment, better displays anatomical structures and measurements can be successfully carried out almost in every patient.

Perfusion CT can predict tumoral grading of pancreatic adenocarcinoma.

OBJECTIVES To describe perfusion CT features of locally advanced pancreatic ductal adenocarcinoma and to evaluate correlation with tumor grading. METHODS Thirty-two patients with locally advanced pancreatic adenocarcinoma were included in this study. Lesions were evaluated by P-CT and biopsy after patients informed consent. P-CT parameters have been assessed on a large single and on 6 small intratumoral ROIs. Values obtained have been compared and related to the tumor grading using Mann-Whitney U test. Sensibility, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy in predicting tumor grading have been calculated for cut-off values chosen by using ROC curves. RESULTS Out of 32 lesions, 12 were classified as low grade and 20 as high grade. A statistically significant difference between high and low grade neoplasms were demonstrated for PEI and BV parameters. PEI and BV cut-off values were respectively 17.8 HU and 14.8 ml/100g. PEI identified high grade neoplasms with a 65% sensitivity, 92% specificity, 93% PPV, 61% NPV and 75% accuracy. BV identified high grade neoplasms with a 80% sensitivity, 75% specificity, 84% PPV, 69% NPV, 78% accuracy. Considering both PEI and BV, P-CT identified high grade lesions with a 60% sensitivity, 100% specificity, 100% PPV, 60% NPV and 75% accuracy. CONCLUSIONS PEI and BV perfusion CT parameters proved their efficiency in identifying high grade pancreatic adenocarcinoma.

Elastography of the pancreas

Elastography has recently been presented in clinical studies as a new technique applied to US imaging. The challenge of this new technique is to distinguish different tissues on the basis of their specific consistency. Since malignant tumors tend to be harder than benign lesions and parenchyma, this new approach could result clinically relevant. Initial clinical experiences in US elastography have been promising in differentiating breast, thyroid and prostate nodules. Pancreatic applications of US elastography are relatively recent and under validation with several studies so far published in literature.

Diagnostic Performance of Contrast-Enhanced Ultrasound (CEUS) and Contrast-Enhanced Endoscopic Ultrasound (ECEUS) for the Differentiation of Pancreatic Lesions: A Systematic Review and Meta-Analysis

PURPOSE To evaluate CEUS for the diagnosis of pancreatic diseases and its application in the clinical routine with a focus on the value of CEUS in ductal pancreatic carcinoma and its use for the differentiation of neoplastic and non-neoplastic lesions. MATERIALS AND METHODS All prospective and retrospective studies published in any language by March 6, 2014 were included based on the following criteria: use of contrast-enhanced ultrasound (CEUS) and contrast-enhanced endoscopic ultrasound (ECEUS) as the imaging methods, use of histology as the reference method and availability of a complete translation. Two authors analyzed the titles and abstracts of the search results to identify all relevant publications. Two independent readers then analyzed the full articles to identify those meeting the inclusion criteria. Details regarding study design, patient characteristics, interventions, and results were then independently extracted by two radiologists and one reviewer with methodological expertise. Sensitivity, specificity and diagnostic odds ratio (DOR) were used to obtain overall estimates. RESULTS 1293 articles were initially identified. 27 studies met the inclusion criteria. CEUS was the index test in 23 studies while ECEUS was the index test in 4 studies. The primary study objective was met by 20 studies with respect to ductal adenocarcinoma. CEUS sensitivity was evaluated in all studies. The pooled estimate of CEUS sensitivity for the diagnosis of ductal adenocarcinoma was 0.89 (95 % CI, 0.85 - 0.92). 15 out of 20 studies examined CEUS specificity. The average specificity was 0.84 (95 % CI, 0.77 - 0.89). The pooled estimate for DOR was 61.12 (95 % CI, 34.81 - 107.32). With regard to the secondary study objective, the pooled sensitivity and specificity were 0.95 (95 % CI, 0.93 - 0.96) from 14 studies and 0.72 (95 % CI, 0.58 - 0.83) from 13 studies, respectively. The pooled DOR was 57.63 (95 % CI, 33.62 - 98.78). CONCLUSION The sensitivity, specificity, and DOR results show the high value of CEUS for the characterization and differentiation of ductal adenocarinomas from other pancreatic diseases and for cystic pancreatic lesions. For this reason and due to their noninvasive nature, CEUS and ECEUS should be used as the first methods for characterizing neoplastic pancreatic lesions, especially since these are often incidental findings. The methods improve the quality of ultrasound diagnostics and result in faster diagnosis and better disease management.

Noninvasive diagnosis of cirrhosis: A review of different imaging modalities

Progressive hepatic fibrosis can lead to cirrhosis, so its early detection is fundamental. Staging fibrosis is also critical for prognosis and management. The gold standard for these aims is liver biopsy, but it has several drawbacks, as it is invasive, expensive, has poor acceptance, is prone to inter observer variability and sampling errors, has poor repeatability, and has a risk of complications and mortality. Therefore, non-invasive imaging tests have been developed. This review mainly focuses on the role of transient elastography, acoustic radiation force impulse imaging, and magnetic resonance-based methods for the noninvasive diagnosis of cirrhosis.

Virtual Analysis of Pancreatic Cystic Lesion Fluid Content by Ultrasound Acoustic Radiation Force Impulse Quantification

The purpose of this study was to prospectively evaluate the application of acoustic radiation force impulse (ARFI) imaging implemented with Virtual Touch tissue quantification (Siemens AG, Erlangen, Germany) in the study of pancreatic cystic lesions by using different analysis methods compared with the final diagnosis (pathologic or by magnetic resonance imaging and endoscopic sonographic findings).

Comparison between CT and CEUS in the diagnosis of pancreatic adenocarcinoma

PURPOSE The aim of this study is to compare CEUS and MDCT features of pancreatic ductal adenocarcinoma in relation to tumor size. MATERIALS AND METHODS All patients with pathological diagnosis of pancreatic adenocarcinoma and studied by means of CEUS and MDCT were enrolled in this study. Two radiologists evaluated tumor size, site and imaging appearance. Patients in which at least one method yielded a positive result were divided into 4 groups on the basis of lesion size. For each dimensional category, sensitivity of the two imaging methods was calculated and compared using McNemar test. RESULTS One hundred thirty-three patients were included in this study. In 9 of 133 patients neither MDCT nor US/CEUS could identify the lesion, while in 9 of 133 patients only MDCT and in 13 of 133 only US/CEUS could identify the lesion. In the remaining 102 patients, both MDCT and US/CEUS yielded a positive result. US/CEUS sensitivity was 86.47% while MDCT sensitivity was 83.58%, with no statistically significant difference (p = 0.523). For lesions smaller than 2 cm US/CEUS had a 100% sensitivity, while MDCT had a 73.33% sensitivity with no statistically significant difference (p = 0.125). For lesions between 2.1 and 3 cm US/CEUS had a sensitivity of 95.35%, while MDCT had a sensitivity of 83.72% with no statistically significant difference (p = 0.180). For lesions between 3.1 and 4 cm, US/CEUS had a sensitivity of 87.88%, while MDCT had a sensitivity of 93.94% with no statistically significant difference (p = 0.688). For lesions larger than 4 cm US/CEUS, had a sensitivity of 90.91%, while MDCT had a sensitivity of 100% with no statistically significant difference (p = 0.250). CONCLUSION US/CEUS sensitivity in diagnosing pancreatic ductal adenocarcinoma is adequate and does not statistically differ from that of MDCT. US/CEUS sensitivity seems to be higher for small and medium lesions, while MDCT sensitivity is higher for large lesions. By combining both the imaging methods a higher accuracy in diagnosing pancreatic ductal adenocarcinoma can be expected.

Malignant focal liver lesions at contrast-enhanced ultrasonography and magnetic resonance with hepatospecific contrast agent

The aim of this study was to compare the diagnostic accuracy of the late phase of CEUS and the hepatobiliary phase of CE-MR with Gd-BOPTA in the characterization of focal liver lesions in terms of benignity and malignancy. A total of 147 solid focal liver lesions (38 focal nodular hyperplasias, 1 area of focal steatosis, 3 regenerative nodules, 8 adenomas, 11 cholangiocarcinomas, 36 hepatocellular carcinomas and 49 metastases) were retrospectively evaluated in a multicentre study, both with CEUS, using sulphur hexafluoride microbubbles (SonoVue, Bracco, Milan, Italy) and CE-MR, performed with Gd-BOPTA (Multihance, Bracco, Milan, Italy). All lesions thought to be malignant were cytohistologically proven, while all lesions thought to be benign were followed up. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values and accuracy were calculated for the late phase of CEUS and the hepatobiliary phase of CE-MRI, respectively, and in combination. Analysis of data revealed 42 benign and 105 malignant focal liver lesions. We postulated that all hypoechoic/hypointense lesions on the two phases were malignant. The diagnostic errors were 13/147 (8.8%) by CEUS and 12/147 (8.2%) by CE-MR. Sensitivity, specificity, PPV, NPV and accuracy of the late phase of CEUS were 90%, 93%, 97%, 80% and 91%, 93%, 97%, 81% and 92% for the hepatobiliary phase of CE-MRI, respectively. If we considered both techniques, the misdiagnosis diminished to 3/147 (2%) and sensitivity, specificity, PPV, NPV and accuracy were 98%, 98%, 99%, 95% and 98%. The combination of the late phase of CEUS and the hepatobiliary phase of CE-MR in the characterization of solid focal liver lesions in terms of benignity and malignancy is more accurate than the two techniques used separately.

Variation of tumoral marker after radiofrequency ablation of pancreatic adenocarcinoma

BACKGROUND To evaluate the correlation between variations of CA 19.9 blood levels and the entity of necrosis at CT after radiofrequency ablation (RFA) of unresectable pancreatic adenocarcinoma. METHODS In this study, from June 2010 to February 2014, patients with diagnosis of unresectable and not metastatic pancreatic ductal adenocarcinoma, expressing tumor marker CA 19.9, treated with RFA procedure were included. All these patients underwent RFA. CT study was performed 1 week after RFA. The dosage of CA 19.9 levels was performed 1 month after RFA. Features of necrosis at CT, as mean entity, density and necrosis percentages compared to the original lesion, were evaluated and compared by using t-test with CA 19.9 blood levels variations after RFA procedure. RESULTS In this study were included 51 patients with diagnosis of unresectable and not metastatic pancreatic ductal adenocarcinoma, expressing tumor marker CA 19.9, treated with RFA procedure and with CT study and CA 19.9 available for analysis. After the procedure, CA 19.9 blood levels reduced in 24/51 (47%), remained stable in 10/51 (20%) and increased in 17/51 (33%). In patients with CA 19.9 levels reduced, the tumor marker were reduced less than 20% in 4/24 (17%) and more than 20% in 20/24 (83%); instead the tumor marker were reduced less than 30% in 8/24 (33%) and more than 30% in 16/24 (67%). At CT scan necrotic area density difference was not statistically significant. Also there was no statistically significant difference among the mean area, the mean volume and the mean ablation volume in percentage related to the treated tumor among the three different groups of patients divided depending on the CA 19.9 blood levels. But a tendency to a statistically significant difference was found in comparing the mean percentage of ablation volume between two subgroups of patients with a decrease of CA 19.9 levels with less or more than 20% reduction of tumor markers and between two subgroups with less or more than 30% reduction of CA 19.9 levels. CONCLUSIONS RFA of unresectable pancreatic adenocarcinoma induces reduction of CA 19.9 blood levels in about half of the cases.