scholarly journals Optimum concentration of iodine contrast agent injection for best stent visualization using Neuroform Atlas stent during stent-assisted coil embolization: Case reviews based on in vitro experiments

2020 ◽  
Vol 11 ◽  
pp. 170
Author(s):  
Shuta Aketa ◽  
Daisuke Wajima ◽  
Masayoshi Kiyomoto ◽  
Natsuhiko Izumi ◽  
Taiji Yonezawa
Keyword(s):  
Contrast Agent ◽  
Internal Carotid ◽  
Region Of Interest ◽  
Training System ◽  
Cone Beam ◽  
Stent Deployment ◽  
Plastic Tube ◽  
Contrast Agent Injection ◽  
Wall Apposition

Background: The present study aimed to evaluate the influence of contrast agent concentration (Conc) on the visibility of Neuroform Atlas in vitro and in clinical cases. Methods: A plastic tube was filled with several Conc. in saline (experiment 1) and blood (experiment 2). Thereafter, the Neuroform Atlas was placed around the plastic tube in an acrylic shield case. In experiment 3, the Neuroform Atlas was placed in the internal carotid artery of the endo vascular evaluator endovascular training system with an injection of several Conc in saline. Five slices of the axial images obtained using the 3D-cone-beam computed tomography (3D-CBCT) with the digital subtraction angiography system were evaluated. A 1-cm2 circular center, which showed the contrast agent in saline or blood, was determined as the region of interest, and its pixels were evaluated. Results: Radiation density (Rd) was directly proportional to the contrast agent in saline and blood (experiment 1: (Rd (pixel)) = 6.8495 × (concentration (%)) + 152.72 (R2 = 0.99), experiment 2: (Rd (pixel)) = 6.2485 × (concentration (%)) + 167.42 (R2 = 0.9966), experiment 3: (Rd (pixel)) = 10.287 × (concentration (%)) + 108.26 (R2 = 0.993)]. Rd calculated similarly in our cases (concentration varied from 5% to 8%) was between the range of “Rd of experiment 2” and “Rd of experiment 3.” Conclusion: Based on our in vitro experiments, with 5–8% concentration, Neuroform Atlas stent deployment with complete neck coverage by the bulging stent and wall apposition was visualized on 3D-CBCT.

scholarly journals Study on Establishing Reference Safe Concentrations of MRI Contrast Agents for Optimized Images: Paramagnetic Gd-DTPA-BMEA and Superparamagnetic Ferucarbotran

2021 ◽  
Vol 11 (3) ◽  
pp. 1165
Author(s):  
Wen-Tien Hsiao ◽  
Yi-Hong Chou ◽  
Jhong-Wei Tu ◽  
Ai-Yih Wang ◽  
Lu-Han Lai
Keyword(s):  
Contrast Agent ◽  
Contrast Agents ◽  
Mri Contrast Agents ◽  
Mri Contrast Agent ◽  
In Vitro Experiments ◽  
Mri Contrast ◽  
In Vivo Experiments ◽  
Contrast Agent Injection

The purpose of this study is to establish the minimal injection doses of magnetic resonance imaging (MRI) contrast agents that can achieve optimized images while improving the safety of injectable MRI drugs. Gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) and ferucarbotran, commonly used in clinical practice, were selected and evaluated with in vitro and in vivo experiments. MRI was acquired using T1-weighted (T1W) and T2-weighted (T2W) sequences, and the results were quantitatively analyzed. For in vitro experiments, results showed that T1W and T2W images were optimal when Gd-DTPA-bisamide (2-oxoethyl) (Gd-DTPA-BMEA) and ferucarbotran were diluted to a volume percentage of 0.6% and 0.05%; all comparisons were significant differences in grayscale statistics using one-way analysis of variance (ANOVA). For in vivo experiments, the contrast agent with optimal concentration percentages determined from in vitro experiments were injected into mice with an injection volume of 100 μL, and the images of brain, heart, liver, and mesentery before and after injection were compared. The statistical results showed that the p values of both T1W and T2W were less than 0.001, which were statistically significant. Under safety considerations for MRI contrast agent injection, optimized MRI images could still be obtained after reducing the injection concentration, which can provide a reference for the safety concentrations of MRI contrast agent injection in the future.

scholarly journals Imaging Artifacts of Nonadhesive Liquid Embolic Agents in Conventional and Cone-beam CT in a Novel in Vitro AVM Model

2021 ◽  
Author(s):  
Niclas Schmitt ◽  
Ralf O Floca ◽  
Daniel Paech ◽  
Rami A El Shafie ◽  
Ulf Neuberger ◽  
...  
Keyword(s):  
Cone Beam Ct ◽  
Three Dimensional ◽  
Region Of Interest ◽  
Cone Beam ◽  
Major Drawback ◽  
Embolic Agents ◽  
Liquid Embolic ◽  
Imaging Artifacts ◽  
Different Diameters

Abstract Background A major drawback of liquid embolic agents (LEAs) is the generation of imaging artifacts (IA), which may represent a crucial obstacle for the detection of periprocedural hemorrhage or subsequent radiosurgery of cerebral arteriovenous malformations (AVMs). This study aimed to compare the IAs of Onyx, Squid and PHIL in a novel three-dimensional in vitro AVM model in conventional computed tomography (CT) and cone-beam CT (CBCT). Methods Tubes with different diameters were configured in a container resembling an AVM with an artificial nidus at its center. Subsequently, the AVM models were filled with Onyx 18, Squid 18, PHIL 25% or saline and inserted into an imaging phantom (n = 10/LEA). Afterwards CT and CBCT scans were acquired. The degree of IAs was graded quantitatively (Hounsfield units in a defined region of interest) and qualitatively (feasibility of defining the nidus)—Onyx vs. Squid vs. PHIL vs. saline, respectively. Results Quantitative density evaluation demonstrated more artifacts for Onyx compared to Squid and PHIL, e.g. 48.15 ± 14.32 HU for Onyx vs. 7.56 ± 1.34 HU for PHIL in CT (p < 0.001) and 41.88 ± 7.22 density units (DU) for Squid vs. 35.22 ± 5.84 DU for PHIL in CBCT (p = 0.044). Qualitative analysis showed less artifacts for PHIL compared to Onyx and Squid in both imaging modalities while there was no difference between Onyx and Squid regarding the definition of the nidus (p > 0.999). Conclusion In this novel three-dimensional in vitro AVM model, IAs were higher for the EVOH/tantalum-based LEAs Onyx and Squid compared to iodine-based PHIL. Onyx induced the highest degree of IAs with only minor differences to Squid.

Scan time adapted contrast agent injection protocols with low volume for low-tube voltage CT angiography: An in vitro study

2017 ◽  
Vol 93 ◽  
pp. 65-69 ◽  
Author(s):  
Matthias R. Benz ◽  
Zsolt Szucs-Farkas ◽  
Johannes M. Froehlich ◽  
Geraldine Stadelmann ◽  
Georg Bongartz ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Ct Angiography ◽  
In Vitro Study ◽  
Vitro Study ◽  
Tube Voltage ◽  
Low Tube Voltage ◽  
Scan Time ◽  
Contrast Agent Injection ◽  
Low Volume

scholarly journals A technical note on intra-arterial cone-beam computed tomography for the evaluation of flow-diverter stents: Image quality differences between diluted and non-diluted contrast medium

2019 ◽  
Vol 26 (2) ◽  
pp. 164-169
Author(s):  
Naci Kocer ◽  
Sedat G Kandemirli ◽  
Daniel Ruijters ◽  
Michalis Mantatzis ◽  
Osman Kizilkilic ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Image Quality ◽  
Contrast Medium ◽  
Cone Beam Computed Tomography ◽  
Vessel Wall ◽  
Flow Diverter ◽  
Cone Beam ◽  
Gray Scale ◽  
Stent Deployment ◽  
Contrast Technique

Background Design of flow-diverter stents for flexibility, tractability, and low profile limits their radiopacity on conventional digital subtraction angiography. Cone-beam computed tomography (CBCT) offers higher spatial resolution for the evaluation of flow-diverter stents. However, CBCT requires optimal dilution and timing of contrast medium for simultaneous visualization of the stent, arterial lumen, and vessel wall. There are only limited data on the effects of different contrast dilutions on CBCT image quality in neurointerventional applications. Materials and methods In our institution, intra-arterial CBCTs were acquired during stent deployment and at follow-ups with 10% diluted contrast. We had recently started acquiring intra-arterial CBCTs with non-diluted contrast. Retrospective analysis of our flow-diverter data identified eight cases with different aneurysm locations who had intra-arterial CBCT with 10% diluted contrast immediately after flow-diverter stent deployment and with non-diluted contrast technique during follow-ups. For each case, the image quality between diluted and non-diluted contrast techniques was compared qualitatively by assessing stent visualization and quantitatively by plotting gray-scale intensity values along the vessel lumen. Results In two sets of CBCT images per each case, there was no substantial difference between diluted and non-diluted CBTC techniques for the evaluation of stent architecture and lumen opacification. Gray-scale intensity values perpendicular to the lumen revealed similar intensity values along the neighboring parenchyma, vessel wall, and lumen for the two different contrast techniques. Conclusion Intra-arterial CBCT angiography can be performed without contrast dilution and still achieve adequate image quality in certain cerebral aneurysms treated with flow diverter. The non-diluted contrast technique avoids the time loss during preparation of diluted contrast and installation of diluted contrast to the injector in angiography suites with a single power injector.

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