Applying Runthrough Guidewire To Transseptal Puncture Without Iodinated Contrast Agent

Aims: Conventional transseptal puncture(TSP) relies on fluoroscopy and iodinated contrast agent to distinctly position the transseptal needle at the left atrium, however, there exists great challenges in clinic in patients with contrast hypersensitivity or allergy-like reactionsin the procedure. This study aimed to evaluate a novel approach to TSP assisted by Runthrough guidewire and fluoroscopy without use of iodinated contrast agent. Methods: Sixty patients with paroxysmal atrial fibrillation undergone radiofrequency catheter ablation were enrolled from February 2021 to October 2021, and randomised to routine TSP group and Runthrough guidewire assisted group. The two groups were compared regarding the total operative time, length of fluoroscopy exposure, difference of radiation dose in X-ray, and the safety was evaluated in the patients undergone TSP without iodinated contrast agent. Results: There were no differences in baseline demographics or clinical characteristics between the two groups. Although the total procedure time[(1.98±0.29) min vs.(2.11±0.14) min, P<0.04],length of fluoroscopic exposure [(1.83±0.30) vs.(1.98±0.14), P<0.19] and radiation dose in X-ray[(27.83±3.21) uGym2vs.(29.13±1.57) uGym2, P<0.30] were somewhat statistically different between groups, yet the difference was insignificant. No complications, including pericardial tamponade and aortic perforation, occurred in all patients. Conclusion: Iodine-free TSP under the guidance of Runthrough guidewire and fluoroscopy can be a simple, safe, economical and effective approach to TSP, and may be reproduced as a novel option for TSP in patients with contrast hypersensitivity or allergy-like reactions.

Multi-contrast CT imaging using a high energy resolution CdTe detector and a CZT photon-counting detector

Computed tomography (CT) imaging with high energy resolution detectors shows great promise in material decomposition and multi-contrast imaging. Multi-contrast imaging was studied by imaging a phantom with iodine (I), gadolinium (Gd), and gold (Au) solutions, and mixtures of the three using a cadmium telluride (CdTe) spectrometer with an energy resolution of 1% as well as with a cadmium zinc telluride (CZT) detector with an energy resolution of 13%. The phantom was imaged at 120 kVp and 1.1 mA with 7 mm of aluminum filtration. For the CdTe data collection, the phantom was imaged using a 0.2 mm diameter x-ray beam with 96 ten-second data acquisitions across the phantom at 45 rotation angles. For the CZT detector, we had 720 projections using a cone beam, and the six detector energy thresholds were set to 23, 33, 50, 64, 81, and 120 keV so that three thresholds corresponded to the K-edges of the contrast agents. Contrast agent isolation methods were then examined. K-edge subtraction and novel spectrometric algebraic image reconstruction (SAIR) were used for the CdTe data. K-edge subtraction alone was used for the CZT data. Linearity plots produced similar R 2 values and slopes for all three reconstruction methods. Comparing CdTe methods, SAIR offered less noise than CdTe K-edge subtraction and better geometric accuracy at low contrast concentrations. CdTe contrast agent images of I, Gd, and Au offered less noise and greater contrast than the CZT images, highlighting the benefits of high energy resolution CdTe detectors for possible use in pre-clinical or clinical CT imaging.

Delineating Toxicity Mechanisms Associated with MRI Contrast Enhancement through a Multidimensional Toxicogenomic Profiling of Gadolinium

Although gadolinium is widely used for magnetic resonance imaging in clinical settings, many concerns regarding its toxicity and bioaccumulation after gadolinium-based contrast agent (GBCA) administration have been raised and published...

Calculation of radiation dose enhancement by gadolinium compounds for radiation therapy

In this study, we evaluate the features of dose enhancement with Gd contrast agent (Magnevist). Due to the increased relaxation time and high atomic number (z=64) Gd can be used in radiation therapy as a radiosensitizer. To perform a quantitative evaluation of the radiosensitization effect is determined a parameter called the dose enhancement factor - DEF. The DEF values were calculated based on the analysis of the mass absorption coefficients for gadolinium and biological tissue. An increase in DEF is observed when the radiation energy is higher than the K-shell ionization energy of Gd atoms. For the presence of 20315 ppm Gd contrast agent in biological tissue the dose enrichment factor is maximum DEF = 4.12 at photon irradiation energy 60 keV. Also, based on calculations for photon irradiation sources considered high degrees of dose enhancement occur for Am-241, Yb-196, and 100 kVp X-ray tube.