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Aim: To differentiate uric acid from non-uric acid renal stones based on their spectral attenuation values.Materials and Methods: The present study was approved by the institutional review board and the need for informed consent was waived. Thirty-three consecutive patients (21 men, 12 women; mean age 55 years) with symptomatic urolithiasis underwent dual-energy computed tomography (DECT) using a second-generation dual-source CT system. Stone composition was assessed by means of chemical analysis after extraction or spontaneous expulsion. The composition of one stone was considered to represent all remaining stones in patients presenting with more than one stone. Image-domain virtual monoenergetic images were generated from the dual-energy datasets. One radiologist evaluated stone attenuation values from 40 to 190 keV; attenuation curves were created and 40/190 keV attenuation ratios calculated. Qualitative evaluation of the spectral attenuation curves was also performed. Imaging findings were compared with laboratory results.Results: Sixty-two stones were considered in 33 patients (mean diameter 6.5 mm). Fifteen of the 62 stones were mainly composed of uric acid and 47/62 of cysteine or calcium oxalates/phosphates. Forty to 190 keV attenuation ratios were significantly lower for uric acid stones (mean 0.87±0.3) than for non-uric acid stones (mean 3.80±0.6; p<0.0001). Accuracy was 100% with a cut-off value of 1.76. Qualitative analysis of spectral attenuation curves showed unique shapes for uric acid and non-uric acid stones.Conclusions: Spectral CT quantitatively and qualitatively differentiates uric acid from non-uric acid stones. [ABSTRACT FROM AUTHOR]

Purpose To determine the accuracy of ENZIAN score, as detected on MR imaging, compared to surgical-pathologic findings. Materials and methods This retrospective study was approved by the investigational review board and the requirement for informed patient consent was waived. 115 patients were included according to following criteria: tubo-ovarian and/or deep endometriosis suspected at physical examination and transvaginal ultrasound; availability of MR examination; histopathological results from laparoscopic or surgical treatment. Exclusion criteria: lack of available MR examination, and/or (b) lack of a definitive histopathological results. Histopathological findings from bioptic specimens obtained during laparoscopic or laparotomic treatment were considered as reference standard. For all detected lesions a score according to ENZIAN score (revised 2010) was assigned both for MRI and histopathological findings. By comparing MRI-ENZIAN score and histopathological-ENZIAN score the overall sensitivity, specificity, accuracy, positive and negative predictive values in relation to presence/absence of deep endometriosis in each patient were calculated. k-Cohen to evaluate the degree of concordance between MRI-ENZIAN score and histopathological-ENZIAN score was also measured. Moreover the sensitivity, specificity, accuracy, positive and negative predictive values for each specific localization provided by ENZIAN score were also calculated. Results At histopathology, the diagnosis of deep endometriosis was confirmed in 82/115 (71.3%) patients. The sensitivity, specificity, accuracy, PPV and NPV of MRI were 94%, 97%, 95%, 99%, 86%, respectively. The highest accuracy was for adenomyosis (100%) and endometriosis of utero-sacral ligaments (USLs) (98%), slightly lower for vagina-rectovaginal septum an colo-rectal walls (96%), and the lowest for bladder endometriosis (92%). The concordance between histopathological and MRI ENZIAN score was excellent ( k = 0.824); in particular it was 0.812 for lesions in vagina-rectovaginal space, 0.890 for lesions in USL, 0.822 for lesions in rectum–sigmoid colon, 1.000 for uterine adenomyosis, and 0.367 for lesions located in the bladder wall. Conclusion MRI correlates with the ENZIAN score and has an accuracy of 95% in the detection and localization of deep endometriosis, allowing to minimize false negative results (4%) in patients with deep endometriosis and to obtain a correct preoperative staging. [ABSTRACT FROM AUTHOR]

Abstract: 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 17.8HU and 14.8ml/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. [Copyright &y& Elsevier]

Purpose: CT perfusion has been proposed for pancreatic lesion characterization. However, scan and analysis protocols influence numerical data. To overcome this, the purpose of our study is to evaluate the use of time-density curves obtained from MDCT perfusion of the pancreas for the characterization of normal parenchyma, adenocarcinoma, chronic pancreatitis and endocrine tumors. Methods: 31 patients with solid pancreatic lesions and 21 patients with renal cell carcinoma underwent 64-row MDCT perfusion of the pancreas after injection of 50 cc of a 370 mg I/ml solution at 5 cc/s. 63 time-density curves were obtained from normal parenchyma (21 patients), adenocarcinoma (25), endocrine tumors (4) and atrophic parenchyma (13). Two readers independently categorized the 63 time-density curves into 4 different morphologies: normal wash-in and wash-out (A), low wash-in followed by plateau (B), low wash-in followed by faint wash-out (C) and high wash-in and wash-out (D). Interobserver agreement was calculated with kappa statistics. Fisher test was used to calculate sensitivity, specificity, positive (PPV) and negative (NPV) predictive values for each type of curve. Results: Interobserver agreement was very good (Kappa=0.849). Curve A had 94.4% sensitivity, 91.1% specificity, 80.95% PPV, 97.6% NPV for 'normal parenchyma'. Curve B had 74.19% sensitivity, 93.75% specificity, 92% PPV, 78.95% NPV in diagnosing 'adenocarcinoma'. Curve C had 45.45% sensitivity, 84.62% specificity, 38.46% PPV, 88% NPV for 'chronic pancreatitis'. Curve D had 100% sensitivity, 98.33% specificity, 75% PPV, 100% NPV for 'endocrine tumor'. Conclusions: The morphology of MDCT perfusion time-density curves appears to be useful in characterizing pancreatic lesions, and might help overcome the differences in scan and postprocessing techniques. [ABSTRACT FROM AUTHOR]

Abstract: 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: 2.17m/s in HCCs, 2.30m/s in hemangiomas, 1.25m/s in adenomas, 2.87m/s in metastases and 2.75m/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. [Copyright &y& Elsevier]

Aim: To correlate the appearance of the retroportal fat plane at preoperative computed tomography (CT) and the pathology findings in resected adenocarcinoma of the pancreatic head (PDAC).Material and Methods: Forty-eight patients with resected PDAC of the pancreatic head were included (24 men, 24 women, mean age 63 years, median BMI 24.1). All patients underwent CT <30 days before surgery. The state of the retroperitoneal resection margin and the presence of lymphatic or perineural invasion were obtained from pathology reports. CT images were reviewed independently by two radiologists for assessment of the retroportal fat plane and graded in two categories (clear/effaced). Inter-reader discrepancies were solved in consensus. Interobserver agreement was calculated and Fisher's test was used to assess the correlation between CT and pathology findings. Visceral fat areas were measured and correlated with CT findings.Results: A clear retroportal fat plane was significantly associated with a negative retroperitoneal margin at pathology with 100% specificity and PPV (p=0.0001). No association was observed between the appearance of the fat plane at CT and the presence of lymphatic or perineural invasion (p=ns). Interobserver agreement for retroportal fat plane evaluation was good (0.741). False-positive cases had a significantly lower visceral fat area than the correctly classified patients (p=0.0480).Conclusions: A clear retroportal fat plane is significantly associated with negative retroperitoneal resection margins at pathology. The lack of visceral adipose tissue can lead to overestimation of retroportal fat plane involvement at preoperative CT. [ABSTRACT FROM AUTHOR]