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 patient's 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.

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

OBJECTIVE: The aim of this paper was to evaluate the application of ARFI ultrasound imaging and its potential value for characterizing focal solid liver lesions. MATERIALS AND METHODS: In this multicentric prospective study, over a total non-consecutive period of four months, all patients underwent ARFI US examination. Two independent operators performed 5 measurements per each lesion and 2 measurements in the surrounding liver. According to the definitive diagnosis, a mean velocity value and standard deviations were obtained in each type of focal solid lesion, compared by using t-test, and the inter-operator evaluation was performed by using the Student's t-test. A comparison between the total mean values of each type of lesion and the mean value of the parenchyma was performed. RESULTS: 40 lesions were evaluated and a total of 400 measurements were obtained. The lesions were: 6/40(15%) hepatocellular carcinomas, 7/40(17.5%) hemangiomas, 5/40(12.5%) adenomas, 9/40(22.5%) metastases and 13/40(32.5%) focal nodular hyperplasias. The total mean values obtained were: 2.17 m/s in HCCs, 2.30 m/s in hemangiomas, 1.25 m/s in adenomas, 2.87 m/s in metastases and 2.75 m/s in FNHs. The inter-operator evaluation resulted non-statistically different (p>0.05). A significant difference (p<0.05) was always found by comparing adenomas to the other lesions. 160 measurements were obtained in the surrounding parenchyma, with a no significant difference between values measured in adenomas and in the surrounding liver. CONCLUSIONS: ARFI technology with Virtual Touch tissue quantification could non-invasively provide significant complementary information regarding the tissue stiffness, useful for the differential diagnosis of focal solid liver lesions.

Accuracy of VirtualTouch Acoustic Radiation Force Impulse (ARFI) imaging for the diagnosis of cirrhosis during liver ultrasonography.

PURPOSE: VirtualTouch is a new technique recently proposed to evaluate liver stiffness during B-mode ultrasonography. The goal of the present study was to analyze the diagnostic accuracy of VirtualTouch in the diagnosis of cirrhosis and its correlation with transient elastography (Fibroscan). MATERIALS AND METHODS: A total of 133 patients with chronic liver disease were enrolled. 90 of 133 underwent VirtualTouch and transient elastography and 70 patients assessed with VirtualTouch were submitted to liver biopsy. Stiffness was assessed by both techniques in the right liver lobe. The diagnostic accuracy for cirrhosis was first assessed in the 90 patients submitted to transient elastography with > 13 kPa (47 % of patients) as diagnostic for cirrhosis values. The best cut-off for cirrhosis with VirtualTouch was then tested in the 70 patients with biopsy (cirrhosis in 38 % of patients). 41 patients were assessed by VirtualTouch by two different operators. RESULTS: The VirtualTouch values in controls, chronic hepatitis and cirrhosis were respectively 113, 147 and 255 cm/sec. The AUROC of liver VirtualTouch for the diagnosis of cirrhosis (reference Fibroscan) was 0.941 with 175 cm/sec as the best cut-off (sensitivity 93.0 %; specificity 85.1 %). VirtualTouch confirmed good performance also in patients with bioptic diagnosis of cirrhosis (AUROC 0.908, sensitivity 81.5 %, specificity 88.4 %,). The correlation of VirtualTouch with transient elastography was strict (r = 0.891) and the correlation in VirtualTouch measurements between two operators was also good (r = 0.874). CONCLUSION: VirtualTouch is able to identify the presence of cirrhosis with good accuracy, shows good interobserver reproducibility and the correlation of its values with those obtained by transient elastography with Fibroscan is good.

Acoustic radiation force impulse (ARFI) ultrasound imaging of pancreatic cystic lesions.

PURPOSE: To evaluate the ARFI ultrasound imaging with Virtual Touch tissue quantification in studying pancreatic cystic lesions, compared with phantom fluid models. MATERIALS AND METHODS: Different phantom fluids at different viscosity or density (water, iodinate contrast agent, and oil) were evaluated by two independent operators. From September to December 2008, 23 pancreatic cystic lesions were prospectively studied. All lesions were pathologically confirmed. RESULTS: Non-numerical values on water and numerical values on other phantoms were obtained. Inter-observer evaluation revealed a perfect correlation (rs=1.00; p<0.0001) between all measurements achieved by both operators per each balloon and fluid. Among the pancreatic cystic lesions, 14 mucinous cystadenomas, 4 pseudocysts, 3 intraductal papillary-mucinous neoplasms and 2 serous cystadenomas were studied. The values obtained ranged from XXXX/0-4,85 m/s in mucinous cystadenomas, from XXXX/0-3,11 m/s in pseudocysts, from XXXX/0-4,57 m/s in intraductal papillary-mucinous neoplasms. In serous cystadenomas all values measured were XXXX/0m/s. Diagnostic accuracy in benign and non-benign differentiation of pancreatic cystic lesions was 78%. CONCLUSIONS: Virtual Touch tissue quantification can be applied in the analysis of fluids and is potentially able to differentiate more complex (mucinous) from simple (serous) content in studying pancreatic cystic lesions.

Acoustic Radiation Force Impulse (ARFI) technique in ultrasound with Virtual Touch tissue quantification of the upper abdomen.

PURPOSE: Virtual Touch tissue quantification is an implementation of ultrasound (US) Acoustic Radiation Force Impulse (ARFI) imaging that provides numerical measurements (wave-velocity values) of tissue stiffness. The aim of this study was to define the normal values of shear-wave speed for the healthy liver, gallbladder, pancreas, spleen and kidneys. MATERIALS AND METHODS: Thirty-five young healthy volunteers underwent Virtual Touch tissue quantification after having signed an informed consent form. All upper abdominal organs were examined by two independent operators. A phantom fluid model was also evaluated. All mean wave-velocity values were analysed and compared. Results. One hundred and forty measurements of liver, pancreas, spleen and kidneys, and 70 measurements of the gallbladder lumen were performed. Twenty measurements on the phantom were also performed. Comparing all measurements separately made by each operator in different parts of the organs, no statistically significant differences were observed. A "XXXX/0" value was always obtained from all measurements performed on the gallbladder lumen and on the phantom fluid model. Liver, pancreas, spleen and kidney mean values were 1.59 m/s, 1.40 m/s, 2.44 m/s and 2.24 m/s, respectively. CONCLUSIONS: Virtual Touch tissue quantification is a new, promising implementation of the US ARFI technique, which provides numerical measurements of tissue stiffness. The mean shear-wave speed is lower in the pancreatic parenchyma than in the liver and kidney, whereas the spleen is characterised by the highest mean value. In simple fluids such as water, the value identified by the system with "XXXX" or 0, is always measured.

Resectable pancreatic adenocarcinoma: is the enhancement pattern at contrast-enhanced ultrasonography a pre-operative prognostic factor?

The aim of our study was to determine whether the enhancement pattern of pancreatic adenocarcinoma at contrast-enhanced ultrasonography (CEUS) is related to patient prognosis after resection. CEUS of 42 resected adenocarcinomas were retrospectively reviewed. Tumors were divided into two groups: group A=poorly vascularized (presence of avascular areas) or group B=well vascularized (absence of avascular areas). All lesions were resected and underwent pathological examination assessing tumor differentiation as: undifferentiated (poorly differentiated) or differentiated (moderately and well differentiated). Mean vascular density (MVD) was also evaluated. CEUS enhancement and pathology were correlated (Spearman's test). Survival was analyzed with the Kaplan-Meier method. Multivariate analysis was performed with the Cox regression model. There were 30 differentiated and 12 undifferentiated adenocarcinomas at pathology. At CEUS, 10 lesions were poorly vascularized, whereas 32 lesions were well vascularized. Positive correlation was observed between CEUS groups and tumoral differentiation (rs=0.51; p=0.001) and between CEUS and MVD (rs=0.74; p<0.0001). Median survival in patients with group A vascularization at CEUS was significantly lower than in group B (p=0.015). Cox proportional hazard model revealed the presence of poorly vascularized tumor at CEUS (p=0.0001) as a predictor of higher mortality. In conclusion, CEUS enables accurate depiction of the vascularization of adenocarcinoma, with positive correlation to histology grade and MVD.

Contrast-enhanced ultrasonography (CEUS) immediately after percutaneous ablation of hepatocellular carcinoma.

PURPOSE: This study evaluated the effectiveness of contrast-enhanced ultrasound (CEUS), performed immediately after percutaneous ethanol injection (PEI) or radiofrequency thermal ablation (RFTA), by comparing results with the computed tomography (CT) follow-up. MATERIALS AND METHODS: Sixty-nine consecutive patients with a diagnosis of hepatocellular carcinoma (HCC) were included in this prospective study. All patients underwent PEI or RFTA. After treatment, three CEUS enhancement patterns were observed: isovascular, hypovascular and avascular, which were compared with the CT findings. Sensitivity of the avascular pattern at CEUS and effectiveness of the ablative procedures were evaluated and compared with the chi-square test. RESULTS: Ninety hypervascular HCCs, with a mean diameter of 2.6 cm (0.5-4.9 cm), underwent PEI (n=54) and RFTA (n=36). In the first group, CT identified complete necrosis in 28/54 (52%) lesions, 21 (75%) of which had avascular, one (4%) isovascular and six (21%) hypovascular patterns at CEUS. In the second group, CT showed complete necrosis in 31/36 (86%) lesions, all (100%) of which had a corresponding avascular pattern at CEUS. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the avascular pattern at CEUS compared with CT findings were 75%, 69%, 72%, 72% and 72% for PEI and 100%, 20%, 89%, 100% and 89%, for RFTA, respectively. A statistically significant difference (p<0.05) between the sensitivity of CEUS after PEI and after RFTA and between the necrosis obtained by RFTA and PEI were observed. CONCLUSIONS: CEUS performed immediately after percutaneous ablation of hepatocellular carcinoma to evaluate treatment efficacy is compulsory in the case of RFTA but not for PEI.

Detection of focal liver lesions: from the subjectivity of conventional ultrasound to the objectivity of volume ultrasound.

PURPOSE: This study was undertaken to establish the reliability of automated volumetric liver scans in detecting focal liver lesions by evaluating the degree of agreement between conventional and volume ultrasound (US) examinations. MATERIALS AND METHODS: Over a period of 3 months, we prospectively studied 100 consecutive patients (36 men and 64 women; age range 15-87 years; mean age 63 years) referred to our institute for US imaging of the liver. Volumetric acquisition of the liver was achieved with a 3D transducer (2.0-5.0 MHz) and a Logiq 9 US scanner. All patients underwent both 2- and 3D US studies performed by two expert radiologists. Volumetric acquisitions were subsequently reviewed by the second radiologist, who was blinded to the first radiologist's report. Three categories were established: 1=presence of focal liver lesions; 2=doubtful finding; 3=absence of focal liver lesions. Concordance between volume US and conventional US was calculated by using the k statistic. RESULTS: Out of 100 patients examined, 39 were found to be affected by focal liver lesions. All volume US examinations were technically adequate, allowing exploration of all hepatic sectors, except for five cases that were marred by major respiratory motion artefacts. Conventional and volume US identified the same number of focal liver lesions, with the exception of four cases of doubtful findings at volume US. Concordance between automated volume US and conventional US of the liver was high (k=0.92). CONCLUSIONS: The identification of focal liver lesions on automated volume US is possible, and the examination shows a high level of concordance with conventional US.

Is intraoperative ultrasound (IOUS) still useful for the detection of liver metastases?

PURPOSE: To evaluate the clinical impact of intraoperative ultrasound (IOUS) in the detection of liver metastases during the years, as compared with those of other imaging modalities. MATERIALS AND METHODS: All IOUS scans performed for detection of liver metastases from 2000 to 2006 were retrospectively reviewed and compared with the results of preoperative imaging modalities: Ultrasound (US), Computed Tomography (CT), and/or Magnetic Resonance (MR). The number of cases in which IOUS and preoperative imaging studies produced discordant results, in terms of presence/absence of focal liver lesions, was calculated per year. Statistical analysis was performed using the McNemar test. A p value < 0.05 was considered statistically significant. RESULTS: Eighty-three IOUS scans performed in 2000-2003 were reviewed, and discordance with preoperative imaging findings was found in 19/83 (23%) cases. Of the 42 IOUS scans done during the 2004-2006 period, 10/42 (24%) showed discordance with preoperative studies. All metastases diagnosed with imaging studies were pathologically confirmed. The number of discordant cases in the two periods were not significantly different (p = 0.2). CONCLUSION: IOUS is still useful in the detection of liver metastases. Its decreased use is probably due to the improved accuracy of preoperative imaging modalities.

The chemistry of iomeprol and physico-chemical properties of its aqueous solutions and pharmaceutical formulations.

The synthesis and the chemical characterization of iomeprol, a new triiodinated nonionic radiographic contrast agent, are reported. The physico-chemical properties both of aqueous solutions of the pure compound and of its pharmaceutical formulations are presented and these last data are compared with those of other contrast media. The pharmaceutical development of the product is described. Iomeprol is obtained via a synthesis which is particularly friendly to the environment. The compound shows an unusually high solubility which allows the formulation of contrast media with the lowest osmolalities and viscosities as compared with corresponding contrast media of the same category. In view of these favourable characteristics and of the remarkably high stability of its solutions, iomeprol for injection is formulated also at 400 mgI/ml, the highest concentration so far available on the market for non-ionic contrast media.

Molecular rearrangement of 5-(a-hydroxy-alkanoylamino)-2,4,6-triiodo-isophthalic acid amides.

Iomeprol, a new nonionic contrast agent, undergoes in alkaline solution a Smiles-type intramolecular rearrangement to give 5-methylaminocarbonylmethoxy-2,4,6-triiodoisophthalic acid-bis-(2,3-dihydroxypropylamide). The rearranged product was isolated and its structure confirmed by spectra and by synthesis. The reaction is reversible and could be extended to some structurally related compounds.