Cardiac magnetic resonance characterization of atrial pseudo-mass in Erdheim-Chester disease

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Adoption of Splenic Enhancement to Time and Trigger the Late Hepatic Arterial Phase During MDCT of the Liver: Proof of Concept and Clinical Feasibility

OBJECTIVE The purpose of this study was to prospectively investigate the clinical feasibility of adopting splenic enhancement for timing and triggering the acquisition of late hepatic arterial phase images during multiphasic liver MDCT for assessment of hypervascular tumors. SUBJECTS AND METHODS Forty-eight patients (33 men, 15 women; median age, 59 years; chronic liver disease, 23 patients; portal venous hypertension, 17 patients) with a total of 81 hypervascular liver tumors underwent liver MDCT by random assignment to one of two scanning protocols. Scanning delay for the late hepatic arterial phase was determined by assessment of time-to-peak splenic enhancement (splenic-triggering protocol) or aortic enhancement (aortic-triggering protocol). Acquisition timing, vascular attenuation, liver attenuation and homogeneity, signal-to-noise ratio, tumor-to-liver contrast, and tumor-to-liver contrast-to-noise ratio were compared. Two blinded independent observers used Likert scales to score timing adequacy (3-point scale), diagnostic confidence (5-point scale), and per lesion conspicuity (4-point scale) for hypervascular tumor detection. RESULTS The splenic- and aortic-triggering protocols had significant differences in mean late hepatic arterial phase imaging timing (splenic, 36 ± 6 seconds; aortic, 32 ± 3 seconds; p = 0.010). Images obtained with the splenic-triggering protocol had significantly better observer-based judgment of adequacy (splenic, 2.04; aortic, 1.58; p = 0.002). Mean attenuation and signal-to-noise ratios from liver and portal vein were significantly higher with the splenic- than with the aortic-triggering protocol (p < 0.0001). The splenic-triggering protocol was associated with significant improvement in homogeneity of liver attenuation (p < 0.0001). Although the splenic-triggering protocol was associated with significantly higher lesion conspicuity than was the aortic-triggering protocol (p = 0.022), there was no significant difference in tumor detection rate. CONCLUSION Our results provide a clinical foundation for and proof of principle that the adoption of splenic enhancement renders an optimal temporal window for late hepatic arterial phase imaging during MDCT of the liver for assessment of hypervascular tumors

Surveillance in a Neonatal Intensive Care Unit Allowed the Isolation of a Strain of VIM-Producing <i>Pantoea brenneri</i>

Here, we describe the isolation of a strain of the genus Pantoea encoding a VIM carbapenemase, the first to our knowledge. The strain, isolated from a rectal swab of a 10-day-old newborn admitted to a neonatal intensive care unit (NICU), was identified through whole-genome sequencing analyses as Pantoea brenneri. The strain harbored the carbapenemases gene blaVIM-1. The prompt application of contact measures and the isolation of the newborn prevented the dissemination of VIM-producing P. brenneri and of the plasmid carrying the VIM-1 gene to other newborns

Systematic review and meta-analysis investigating the diagnostic yield of dual-energy CT for renal mass assessment

OBJECTIVE. The objective of our study was to perform a systematic review and meta-analysis to evaluate the diagnostic accuracy of dual-energy CT (DECT) for renal mass evaluation. MATERIALS AND METHODS. In March 2018, we searched MEDLINE, Cochrane Database of Systematic Reviews, Embase, and Web of Science databases. Analytic methods were based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Pooled estimates for sensitivity, specificity, and diagnostic odds ratios were calculated for DECT-based virtual monochromatic imaging (VMI) and iodine quantification techniques as well as for conventional attenuation measurements from renal mass CT protocols. I 2 was used to evaluate heterogeneity. The methodologic quality of the included studies and potential bias were assessed using items from the Quality Assessment Tool for Diagnostic Accuracy Studies 2 (QUADAS-2). RESULTS. Of the 1043 articles initially identified, 13 were selected for inclusion (969 patients, 1193 renal masses). Cumulative data of sensitivity, specificity, and summary diagnostic odds ratio for VMI were 87% (95% CI, 80–92%; I 2 , 92.0%), 93% (95% CI, 90–96%; I 2 , 18.0%), and 183.4 (95% CI, 30.7–1093.4; I 2 , 61.6%), respectively. Cumulative data of sensitivity, specificity, and summary diagnostic odds ratio for iodine quantification were 99% (95% CI, 97–100%; I 2 , 17.6%), 91% (95% CI, 89–94%; I 2 , 84.2%), and 511.5 (95% CI, 217–1201; I 2 , 0%). No significant differences in AUCs were found when comparing iodine quantification to conventional attenuation measurements (p = 0.79). CONCLUSION. DECT yields high accuracy for renal mass evaluation. Determination of iodine content with the iodine quantification technique shows diagnostic accuracy similar to conventional attenuation measurements from renal mass CT protocols. The iodine quantification technique may be used to characterize incidental renal masses when a dedicated renal mass protocol is not available

Interdependencies of acquisition, detection, and reconstruction techniques on the accuracy of iodine quantification in varying patient sizes employing dual-energy CT.

PURPOSE To assess the impact of patient habitus, acquisition parameters, detector efficiencies, and reconstruction techniques on the accuracy of iodine quantification using dual-source dual-energy CT (DECT). MATERIALS AND METHODS Two phantoms simulating small and large patients contained 20 iodine solutions mimicking vascular and parenchymal enhancement from saline isodensity to 400 HU and 30 iodine solutions simulating enhancement of the urinary collecting system from 400 to 2,000 HU. DECT acquisition (80/140 kVp and 100/140 kVp) was performed using two DECT systems equipped with standard and integrated electronics detector technologies. DECT raw datasets were reconstructed using filtered backprojection (FBP), and iterative reconstruction (SAFIRE I/V). RESULTS Accuracy for iodine quantification was significantly higher for the small compared to the large phantoms (9.2 % ± 7.5 vs. 24.3 % ± 26.1, P = 0.0001), the integrated compared to the conventional detectors (14.8 % ± 20.6 vs. 18.8 % ± 20.4, respectively; P = 0.006), and SAFIRE V compared to SAFIRE I and FBP reconstructions (15.2 % ± 18.1 vs. 16.1 % ± 17.6 and 18.9 % ± 20.4, respectively; P ≤ 0.003). A significant synergism was observed when the most effective detector and reconstruction techniques were combined with habitus-adapted dual-energy pairs. CONCLUSION In a second-generation dual-source DECT system, the accuracy of iodine quantification can be substantially improved by an optimal choice and combination of acquisition parameters, detector, and reconstruction techniques. KEY POINTS • Iodine quantification techniques are not immune to error • Systematic deviations between the measured and true iodine concentrations exist • Acquisition parameters, detector efficiencies, and reconstruction techniques impact accuracy of iodine quantification