Structure–Relaxivity Mechanism of an Ultrasmall Ferrite Nanoparticle T1 MR Contrast Agent: The Impact of Dopants Controlled Crystalline Core and Surface Disordered Shell

Objective: To compare injector-based contrast agent (CA) administration with hand injection in magnetic resonance angiography (MRA). Methods: Gadobutrol was administered in 6 minipigs with 3 protocols: (a) hand injection (one senior technician), (b) hand injection (6 less-experienced technicians), and (c) power injector administration. The arterial bolus shape was quantified by test bolus measurements. A head and neck MRA was performed for quantitative and qualitative comparison of signal enhancement. Results: A significantly shorter time to peak was observed for protocol C, whereas no significant differences between protocols were found for peak height and bolus width. However, for protocol C, these parameters showed a much lower variation. The MRA revealed a significantly higher signal-to-noise ratio for injector-based administration. A superimposed strong contrast of the jugular vein was found in 50% of the hand injections. Conclusions: Injector-based CA administration results in a more standardized bolus shape, a higher vascular contrast, and a more robust visualization of target vessels.

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Quantitative myocardial perfusion magnetic resonance imaging: the impact of pulsatile flow on contrast agent bolus dispersion

Physics in Medicine and Biology ◽

10.1088/0031-9155/56/16/006 ◽

2011 ◽

Vol 56 (16) ◽

pp. 5167-5185 ◽

Cited By ~ 7

Author(s):

Dirk Graafen ◽

Julia Hamer ◽

Stefan Weber ◽

Laura M Schreiber

Keyword(s):

Magnetic Resonance Imaging ◽

Magnetic Resonance ◽

Myocardial Perfusion ◽

Contrast Agent ◽

Pulsatile Flow ◽

Perfusion Magnetic Resonance Imaging ◽

Resonance Imaging ◽

Quantitative Myocardial Perfusion ◽

The Impact ◽

Contrast Agent Bolus

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Manganese ferrite nanoparticle micellar nanocomposites as MRI contrast agent for liver imaging

Biomaterials ◽

10.1016/j.biomaterials.2009.02.001 ◽

2009 ◽

Vol 30 (15) ◽

pp. 2919-2928 ◽

Cited By ~ 240

Author(s):

Jian Lu ◽

Shuli Ma ◽

Jiayu Sun ◽

Chunchao Xia ◽

Chen Liu ◽

...

Keyword(s):

Contrast Agent ◽

Mri Contrast Agent ◽

Liver Imaging ◽

Manganese Ferrite ◽

Mri Contrast ◽

Ferrite Nanoparticle

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Imaging the effect of the circadian light–dark cycle on the glymphatic system in awake rats

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1914017117 ◽

2019 ◽

Vol 117 (1) ◽

pp. 668-676 ◽

Cited By ~ 9

Author(s):

Xuezhu Cai ◽

Ju Qiao ◽

Praveen Kulkarni ◽

Ian C. Harding ◽

Eno Ebong ◽

...

Keyword(s):

Blood Flow ◽

Contrast Agent ◽

Brain Temperature ◽

Dark Cycle ◽

Brain Areas ◽

Glymphatic System ◽

Contrast Enhanced ◽

The Impact ◽

The Brain ◽

Awake Rats

The glymphatic system functions in the removal of potentially harmful metabolites and proteins from the brain. Dynamic, contrast-enhanced MRI was used in fully awake rats to follow the redistribution of intraventricular contrast agent entrained to the light–dark cycle and its hypothetical relationship to the sleep–waking cycle, blood flow, and brain temperature in specific brain areas. Brain areas involved in circadian timing and sleep–wake rhythms showed the lowest redistribution of contrast agent during the light phase or time of inactivity and sleep in rats. Global brain redistribution of contrast agent was heterogeneous. The redistribution was highest along the dorsal cerebrum and lowest in the midbrain/pons and along the ventral surface of the brain. This heterogeneous redistribution of contrast agent paralleled the gradients and regional variations in brain temperatures reported in the literature for awake animals. Three-dimensional quantitative ultrashort time-to-echo contrast-enhanced imaging was used to reconstruct small, medium, and large arteries and veins in the rat brain and revealed areas of lowest redistribution overlapped with this macrovasculature. This study raises new questions and theoretical considerations of the impact of the light–dark cycle, brain temperature, and blood flow on the function of the glymphatic system.

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The Impact of Gadolinium-based Contrast Agent for Carbon Ion Radiotherapy

Japanese Journal of Radiological Technology ◽

10.6009/jjrt.2016_jsrt_72.12.1230 ◽

2016 ◽

Vol 72 (12) ◽

pp. 1230-1236

Author(s):

Nao Mogi ◽

Makoto Sakai ◽

Ryosuke Okada ◽

Yusuke Itabashi ◽

Yasuhiro Fukushima ◽

...

Keyword(s):

Contrast Agent ◽

Carbon Ion Radiotherapy ◽

Carbon Ion ◽

The Impact

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Personalized computed tomography – Automated estimation of height and weight of a simulated digital twin using a 3D camera and artificial intelligence

RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren ◽

10.1055/a-1253-8558 ◽

2020 ◽

Author(s):

Frederik Geissler ◽

Rafael Heiß ◽

Markus Kopp ◽

Marco Wiesmüller ◽

Marc Saake ◽

...

Keyword(s):

Computed Tomography ◽

Clinical Practice ◽

Contrast Agent ◽

Reference Values ◽

Medical Staff ◽

The Body ◽

Digital Twin ◽

Twin Model ◽

3D Camera ◽

The Impact

Purpose The aim of this study was to develop an algorithm for automated estimation of patient height and weight during computed tomography (CT) and to evaluate its accuracy in everyday clinical practice. Materials and methods Depth images of 200 patients were recorded with a 3D camera mounted above the patient table of a CT scanner. Reference values were obtained using a calibrated scale and a measuring tape to train a machine learning algorithm that fits a patient avatar into the recorded patient surface data. The resulting algorithm was prospectively used on 101 patients in clinical practice and the results were compared to the reference values and to estimates by the patient himself, the radiographer and the radiologist. The body mass index was calculated from the collected values for each patient using the WHO formula. A tolerance level of 5 kg was defined in order to evaluate the impact on weight-dependent contrast agent dosage in abdominal CT. Results Differences between values for height, weight and BMI were non-significant over all assessments (p > 0.83). The most accurate values for weight were obtained from the patient information (R² = 0.99) followed by the automated estimation via 3D camera (R² = 0.89). Estimates by medical staff were considerably less precise (radiologist: R² = 0.78, radiographer: R² = 0.77). A body-weight dependent dosage of contrast agent using the automated estimations matched the dosage using the reference measurements in 65 % of the cases. The dosage based on the medical staff estimates would have matched in 49 % of the cases. Conclusion Automated estimation of height and weight using a digital twin model from 3D camera acquisitions provide a high precision for protocol design in computer tomography. Key points: Citation Format

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Abstract W P72: Quantitative Analysis of The Blood Flow Reduction In Brain Aneurysms Treated By Flow Diverter Stents

Stroke ◽

10.1161/str.46.suppl_1.wp72 ◽

2015 ◽

Vol 46 (suppl_1) ◽

Author(s):

Aichi Chien ◽

Qianyi Yu ◽

Dominique Zosso

Keyword(s):

Blood Flow ◽

Image Quality ◽

Contrast Agent ◽

Flow Diverter ◽

Input Image ◽

Mixture Ratio ◽

Flow Reduction ◽

Blood Flow Reduction ◽

Brain Aneurysms ◽

The Impact

Purpose: This pilot study demonstrates an approach to quantitatively analyze the blood flow reduction in intracranial aneurysms treated by flow diverter stents (FDS). Method: 2D digital subtraction angiography (DSA) images from 13 aneurysm patients were analyzed with the model. Each patient had 2 sets of consecutive DSA images (3 frames/sec and 6 ml/sec contrast injection rate) acquired before and after FDS treatment. The mean age of the patients was 55, ranging from 5 to 86 years old. The model extracted contrast-agent concentration profiles from each DSA image’s ROIs (inlet, aneurysm, and outlet regions) to calculate the blood contrast-agent mixture ratio, which reflected the percentage of blood not being diverted into aneurysm. To evaluate image quality, signal-to-noise ratio (SNR) and the relative-standard-deviation (RSD, a measure of results’ dispersion), 10 additional sets of ROIs were randomly generated for each DSA image set and also analyzed. Result: The model showed that the 13 patients’ blood contrast-agent mixture ratios increased by 48% on average after FDS treatment. This demonstrates that the blood flow into the aneurysms was significantly ( p < 0.0006) reduced after FDS treatment. The study also found an inverse relationship between the input image SNR and the RSD of output results. The correlation coefficient of image SNR and mixture ratio RSD was -0.6257 for pre-FDS treatment image sets, and -0.4512 for post-FDS treatment image sets. To control the dispersion of results for future studies, images with SNR > 11.2487 were recommended in order to yield results with RSD < 0.15 for 95% C.I. Conclusion: Blood flow reduction due to FDS treatment in patients with brain aneurysms can be measured directly by 2D DSA. This study also verified the impact of input image quality on flow reduction estimation.

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