New infusion device for use in acquisition of images during endovascular procedures: an experimental model

Background The contrast power injector (CPI) is the gold standard method for injecting contrast with the pressure and flow needed to generate a satisfactory images during endovascular procedures, but it is an expensive tool, narrowing its wide-scale applications. One alternative is the manual injection (MI) method, but this does not generate the pressure required for adequate visualization of anatomy. It is therefore imperative to create an alternative low-cost method that is capable of producing high quality images. Objectives To compare the injection parameters of a new mechanical device (Hand-Crank) created in a university hospital with the MI method and with the contrast power injector’s ideal values. Methods A circulation phantom was constructed to simulate the pressure in the aorto-iliac territory and the injection parameters of the two methods were compared in a laboratory setting. Student’s t test and the Mann-Whitney test were used for statistical analysis. Three vascular surgery residents (the authors) performed the injections (each performed 9 tests using conventional manual injection and 9 tests using the Hand-Crank, totaling 54 injections). Results There were statistical differences between the two methods (p<0.05) in total volume injected until maximum pressure was attained, pressure variation, maximum pressure, total injection time, and time to reach the maximum pressure. Conclusions The Hand-Crank can achieve higher maximum pressure, higher average flow, and lower injection time than the manual method. It is a simple, low-cost, and effective tool for enhancing injection parameters in an experimental setup. It could help to produce higher quality images in a clinical scenario.

Misplacement of piccs following power-injected CT contrast media

Peripherally inserted central catheters (PICCs) may be used to administer contrast injection during CT (computed tomography) scans to improve diagnostic accuracy. This is usually done with the use of a power injector. Research has shown that misplacement of catheters following contrast injection can occur. The aim of this review was to analyse appropriately positioned pre-scan PICCs that malposition following injection of contrast media during a CT scan, evaluate whether tip location or right or left insertion plays a part in the displacement of PICCs after CT, and to ensure those involved are aware of the risks and the safety checks required following such procedures. A quantitative method was used, gathering information from the team's insertion database to review 2045 records of contrast-injectable PICCs between 1 January 2015 and 30 April 2020. Analysis of the data indicated that 1% of appropriately sited PICCs malposition following contrast CT injection and that the catheter is able to self-correct back to its original position at an average interval of 24–72 hours without any other intervention. Further research is needed to explore other factors that could influence the rate of self-correction and complications of prolonged catheter malposition.

Optimal dilution of contrast medium for quantitating parenchymal blood volume using a flat-panel detector

Objective Similar to perfusion studies after acute ischemic stroke, measuring cerebral blood volume (CBV) via C-arm computed tomography before and after therapeutic interventions may help gauge subsequent revascularization. We tested serial dilutions of intra-arterial injectable contrast medium (CM) to determine the optimal CM concentration for quantifying parenchymal blood volume by flat-panel detector imaging (FD-PBV). Methods CM was diluted via saline power injector, instituting time delays for FD-PBV studies. A red/green/blue (RGB) color scale was employed to quantify/compare FD-PBV and magnetic resonance-derived CBV (MRCBV). Results Contrast values of right and left common carotid arteries did not differ significantly at CM dilutions of ≥20%. RGB analysis of FD-PBV imaging (relative to MR-CVB), showed CM dilution altered the colors (by 16%), increasing red and decreasing blue ratios. Conclusion Diluting CM to 20% resulted in no laterality differential of FD-PBV imaging, with left/right quantitative ratios approaching 1.1 (optimal for clinical use).