Radiology departmental policy compliance with Swedish guidelines regarding post-contrast acute kidney injury for examinations with iodinated contrast media

Introduction: Guidelines concerning intravenous iodinated contrast media (CM) during computed tomography (CT) examinations are important to follow to minimize the risk for post-contrast acute kidney injury (PC-AKI). The purpose of this study was to investigate the radiology departmental policy compliance with Swedish guidelines concerning PC-AKI. Methods: In February 2020, an electronic survey was distributed to the responsible radiographer at 41 radiology departments in all university hospitals and medium-sized hospitals in Sweden. The questions focused on routines around renal functional tests, individualized contrast administration and handling of patients with diabetes mellitus taking metformin. Results: The response rate was 83%. Seventy-six percent (n = 26) of radiology departments calculated estimated glomerular filtration rate (eGFR) from serum creatinine prior to CM administration, but only 24% (n = 8) followed the recommendation to calculate eGFR from both serum creatinine and cystatin C. For acute/inpatients, 55% (n = 18) followed the recommendation that renal functional tests should be performed within 12 h before CM administration. For elective patients, 97% (n = 33) followed the recommendation to have eGFR newer than three months which is acceptable for patients with no history of disease that may have affected renal function. Approximately 80% of the radiology departments followed the recommendation that CM dose always should be individually adjusted to patient eGFR. Seventy-six percent (n = 26) followed the recommendation to continue with metformin at eGFR > 45 ml/min. Conclusion: Compliance with the national guidelines was high regarding routines around renal functional tests, dose adjustment of CM and metformin discontinuation. Improvements can be made in using both cystatin C and serum creatinine for eGFR calculations as well as ensuring renal function tests within 12 h for acute/inpatients with acute disease that may affect renal function. Implications for practice: This study raises awareness of the importance of adhering to guidelines in healthcare. To have knowledge about the current level of compliance regarding PCI-AKI is important to maintain and develop effective clinical implementation of guidelines. The variation in practice seen in this study emphasizes the need of more effective implementation strategies to ensure adherence with best practice. (C) 2021 The College of Radiographers. Published by Elsevier Ltd

Endocardial border delineation capability of a novel multimodal polymer-shelled contrast agent

Background A novel polymer-shelled contrast agent (CA) with multimodal and target-specific potential was developed recently. To determine its ultrasonic diagnostic features, we evaluated the endocardial border delineation as visualized in a porcine model and the concomitant effect on physiological variables. Methods Three doses of the novel polymer-shelled CA (1.5 ml, 3 ml, and 5 ml [5 × 108 microbubbles (MBs)/ml]) and the commercially available CA SonoVue (1.5 ml [2–5 × 108 MBs/ml]) were used. Visual evaluations of ultrasound images of the left ventricle were independently performed by three observers who graded each segment in a 6-segment model as either 0 = not visible, 1 = weakly visible, or 2 = visible. Moreover, the duration of clinically useful contrast enhancement and the left ventricular opacification were determined. During anesthesia, oxygen saturation, heart rate, and arterial pressure were sampled every minute and the effect of injection of CA on these physiological variables was evaluated. Results The highest dose of the polymer-shelled CA gave results comparable to SonoVue. Thus, no significant difference in the overall segment score distribution (2-47-95 vs. 1-39-104), time for clinically sufficient contrast enhancement (20–40 s for both) and left ventricular overall opacification was found. In contrast, when comparing the endocardial border delineation capacity for different regions SonoVue showed significantly higher segment scores for base and mid, except for the mid region when injecting 1.5 ml of the polymer-shelled CA. Neither high nor low doses of the polymer-shelled CA significantly affected the investigated physiological variables. Conclusions This study demonstrated that the novel polymer-shelled CA can be used in contrast-enhanced diagnostic imaging without influence on major physiological variables

Investigation of the elimination process of a multimodal polymer-shelled contrast agent in rats using ultrasound and transmission electron microscopy

BACKGROUND: A novel polymer-shelled contrast agent (CA) with multimodal imaging and target specific potential was developed recently and tested for its acoustical properties using different in-vitro setups. OBJECTIVE: The aim of this study was to investigate the elimination of three types of the novel polymer-shelled CA, one unmodified and two shell modified versions, in rats. METHODS: The blood elimination time was estimated by measuring the image intensity, from ultrasound images of the common carotid artery, over time after a bolus injection of the three types of the novel CA. The commercially available CA SonoVue was used as a reference. The subcellular localization of the three CAs was investigated using transmission electron microscopy. RESULTS: The ultrasound measurements indicated a blood half-life of 17–85 s for the different types of the novel CA, which was significant longer than the blood half-life time for SonoVue. Additionally, CAs were exclusively found in the circulatory system, either taken up by, or found in the vicinity of macrophages. CONCLUSIONS: Compared to the commercially available CA SonoVue, the blood circulation times for the three types of the novel polymer-shelled CA were prolonged. Moreover, macrophages were suggested to be responsible for the elimination of the CA. Keywords: Contrast agent, polymer, subcellular localization, transmission electron microscope, ultrasound imagin

In video war games, are military personnel’s fixation patterns different compared with those of civilians?

For combat personnel in urban operations, situational awareness is critical and of major importance for a safe and efficient performance. One way to train situational awareness is to adopt video games. Twenty military and 20 civilian subjects played the game “Close Combat: First to Fight” on two different platforms, Xbox and PC, wearing an eye tracker. The purpose was to investigate if the visual search strategies used in a game correspond to live training, and how military-trained personnel search for visual information in a game environment. A total of 27,081 fixations were generated through a centroid mode algorithm and analyzed frame-by-frame, 48% of them from military personnel. Military personnel’s visual search strategies were different from those of civilians. Fixation durations were, however, equally short, that is, about 170 ms, for both groups. Surprisingly, the military-trained personnel’s fixation patterns were less orientated towards tactical objects and areas of interest than the civilians’; the underlying mechanisms remaining unclear. Military training was apparently not advantageous with respect to playing “Close Combat: First to Fight”. Further research within the area of gaming, military training and visual search strategies is warranted

Fixation identification in centroid versus start-point modes using eye-tracking data

Fixation-identification algorithms, needed for analyses of eye movements, may typically be separated into three categories, viz. (i) velocity-based algorithms, (ii) area-based algorithms, and (iii) dispersion-based algorithms. Dispersion-based algorithms are commonly used but this application introduces some difficulties, one being optimization. Basically, there are two modes to reach this goal of optimization, viz., the start-point mode and the centroid mode. The aim of the present study was to compare and evaluate these two dispersion-based algorithms. Manual inspections were made of 1,400 fixations in each mode. Odds ratios showed that by using the centroid mode for fixation detection, a valid fixation is 2.86 times more likely to be identified than by using the start-point mode. Moreover, the algorithm based on centroid mode dispersion showed a good interpretation speed, accuracy, robustness, and ease of implementation, as well as adequate parameter settings. © Perceptual and Motor Skills 2008