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Purpose: To investigate the hemodynamic changes in liver cirrhosis by comparing iodine density in hepatic and splenic parenchyma with 8 cm detector dual energy CT (DECT)., Materials and Methods: Forty-six consecutive patients with liver cirrhosis and 22 healthy volunteers were recruited in this study, and they were all performed contrast enhanced examination with 8 cm detector DECT. All raw data were reconstructed with 1.25 mm slice thickness, Iodine density (in milligrams per milliliter) were measured on iodine-based material decomposition images. Quantitative indices of iodine density (ID), including normalized ID of liver parenchyma for arterial phase (NID LAP ), ID of liver parenchyma for venous phase (ID LVP ), ID of splenic parenchyma for arterial phase (ID SAP ), ID of splenic parenchyma for venous phase (ID SVP ), ID of portal vein in venous phase (ID PVP ) and Liver arterial iodine density fraction (AIF) were measured and compared between two groups. The correlation between Child-Pugh grade and other quantitative indices were calculated, with statistical significance as P<0.05., Results: For all 46 liver cirrhosis patients, 10 were classified in grade A, 24 in Grade B and 12 in Grade C. Compared with control group, patients with liver cirrhosis showed (1) no statistical difference in general data (age, gender, height and weight) (all P>0.05), (2) higher iodine density of NID LAP , ID SVP , ID PVP and AIF, and lower NID SAP (all P<0.01), (3) NID LAP , AIF, ID SVP and ID PVP in grade A were all lower than Grade B and C (all P<0.01). (4) AIF and NID LAP showed positive correlation with Child-Pugh grade, with coefficient of R = 0.71 and R = 0.46, respectively., Conclusion: Based on iodine density measurement in DECT, it is possible to evaluate the hemodynamic changes in liver and spleen parenchyma in liver cirrhosis. Quantitative indices of AIF and NID LAP demonstrate positive correlation with Child-Pugh grade, which accommodates potential possibility for DECT as a noninvasive tool in assessing the severity of liver cirrhosis., (Copyright © 2018 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: To assess the diagnostic value of dual-energy (DE) computed tomography pulmonary angiography (CTPA) for acute pulmonary embolism (PE) using a helical DE scan mode with rapid kVp switching., Materials and Methods: Seventy-six patients with suspected acute PE underwent DE CTPA. Two readers independently assessed and measured the iodine maps. CTPA images were assessed for the presence, location, and degree of PE as the standard of reference. Iodine maps were used to identify the perfusion defect (PD), and the diagnostic accuracy of iodine maps was calculated. The iodine concentrations of PDs and normal lung parenchyma were also measured and compared., Results: A per-patient analysis showed the 84.6% sensitivity and 96.0% specificity of iodine map for PE, and on per-segment analysis, the sensitivity and specificity for PE were 82.9% and 99.6%, respectively. Intraobserver and interobserver variability correlations were excellent, with k values from 0.806 to 1.000. Quantitative analysis showed there was a significant difference for iodine concentration between circumscribed/patchy PDs or wedge-shaped PDs consistent with PE and normal lung parenchyma (P < .05). The intraobserver reliability of reader 1 was from 0.928 to 0.997, and reader 2 was from 0.912 to 0.995. And, the interobserver reliability between two readers was from 0.967 to 0.999., Conclusions: CTPA based on DE scanning with rapid kVp switching can provide both morphologic analysis and quantitative evaluation of PD related to acute PE in addition to standard CTPA data. Quantification of iodine concentration may be helpful for identifying the presence or absence of PE., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: The aim of the present study was to characterize the kinetics of two nanoparticle-based contrast agents for preclinical imaging, Exitron nano 6000 and Exitron nano 12000, and the iodinated agent eXIA 160 in both healthy mice and in a mouse model of hepatocellular carcinoma (HCC). Semiautomatic segmentation of liver lesions for estimation of total tumor load of the liver was evaluated in HCC mice., Materials and Methods: The normal time course of contrast enhancement was assessed in 15 healthy C57BL/6 mice. Imaging of tumor spread in the liver was evaluated in 15 mice harboring a transgenic HCC model (ASV-B mice). Automatic segmentation of liver lesions for determination of total tumor burden of the liver was tested in three additional ASV-B mice before and after an experimental therapy., Results: In healthy mice, clearance of the contrast agent from blood was completed within 3-4 hours for eXIA 160 and Exitron nano 6000, whereas complete blood clearance of Exitron nano 12000 required about 24 hours. eXIA 160 provided maximum liver contrast at 1 hour post injection (p.i.) followed by a continuous decline. Enhancement of liver contrast with Exitron nano 6000 and Exitron nano 12000 reached a plateau at about 4 hours p.i., which lasted until the end of the measurements at 96 hours p.i. Maximum contrast enhancement of the liver was not statistically different between Exitron nano 6000 and Exitron nano 12000, but was about three times lower for eXIA 160 (P < .05). Visually Exitron nano 12000 provided the best liver-to-tumor contrast. Semiautomatic liver and tumor segmentation was feasible after the administration of Exitron nano 12000 but did not work properly for the other two contrast agents., Conclusions: Both nanoparticle-based contrast agents provided stronger and longer lasting contrast enhancement of healthy liver parenchyma. Exitron nano 12000 allowed automatic segmentation of tumor lesions for estimation of the total tumor load in the liver., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Rationale and Objectives: We evaluated the effect of time and dose on lymph node iodine uptake after subcutaneous or submucosal administration of iodinated nanoparticles used for computed tomography lymphography., Methods: We injected 0.1-6 ml of a 15% wt/vol iodinated nanoparticle suspension into the distal extremities subcutaneously (n = 5) or into the buccal submucosa (n = 7) of normal dogs. Precontrast and 4, 12, 24, and 48 hr after contrast administration, CT scans of opacified lymph nodes were obtained. Iodine concentration, node volume, and total iodine uptake were estimated for each node., Results: All estimated parameters increased between 4 and 12 hr postcontrast (p < .05), with no significant increase thereafter. At 24 hr postcontrast, iodine concentration ranged from 0.01 to 16.1 mg/ml (47-568 Hounsfield units). The average iodine concentration and total iodine uptake increased with contrast dose (p < .05) for all lymph node groups evaluated. Node opacification also revealed internal architectural detail., Conclusion: Subcutaneous and submucosal injections of iodinated nanoparticles result in a dose-dependent iodine uptake in targeted lymph nodes. In addition, architectural detail within opacified nodes can be visualized.