scholarly journals Simulation of Contrast Agent Transport in Arteries with Multilayer Arterial Wall: Impact of Arterial Transmural Transport on the Bolus Delay and Dispersion

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Min Xu ◽  
Xiao Liu ◽  
Ang Li ◽  
Yubo Fan ◽  
Anqiang Sun ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Flow Pattern ◽  
Transit Time ◽  
Arterial Wall ◽  
Transport Function ◽  
Disturbed Flow ◽  
Vascular Transport ◽  
Dsc Mri ◽  
Simulated Flow ◽  
Contrast Agent Bolus

One assumption of DSC-MRI is that the injected contrast agent is kept totally intravascular and the arterial wall is impermeable to contrast agent. The assumption is unreal for such small contrast agent as Gd-DTPA can leak into the arterial wall. To investigate whether the unreal assumption is valid for the estimation of the delay and dispersion of the contrast agent bolus, we simulated flow and Gd-DTPA transport in a model with multilayer arterial wall and analyzed the bolus delay and dispersion qualified by mean vascular transit time (MVTT) and the variance of the vascular transport function. Factors that may affect Gd-DTPA transport hence the delay and dispersion were further investigated, such as integrity of endothelium and disturbed flow. The results revealed that arterial transmural transport would slightly affect MVTT and moderately increase the variance. In addition, although the integrity of endothelium can significantly affect the accumulation of contrast agent in the arterial wall, it had small effects on the bolus delay and dispersion. However, the disturbed flow would significantly increase both MVTT and the variance. In conclusion, arterial transmural transport may have a small effect on the bolus delay and dispersion when compared to the flow pattern in the artery.

Cerebral vascular mean transit time determined by PET and DSC-MRI

2005 ◽  
Vol 25 (1_suppl) ◽  
pp. S676-S676
Author(s):  
Masanobu Ibaraki ◽  
Hiroshi Ito ◽  
Eku Shimosegawa ◽  
Hideto Toyoshima ◽  
Keiichi Ishigame ◽  
...  
Keyword(s):  
Transit Time ◽  
Mean Transit Time ◽  
Dsc Mri ◽  
Cerebral Vascular

Contrast Agent Bolus Dispersion in a Realistic Coronary Artery Geometry: Influence of Outlet Boundary Conditions

2013 ◽  
Vol 42 (4) ◽  
pp. 787-796 ◽  
Author(s):  
Karsten Sommer ◽  
Regine Schmidt ◽  
Dirk Graafen ◽  
Hanns-Christian Breit ◽  
Laura M. Schreiber
Keyword(s):  
Coronary Artery ◽  
Boundary Conditions ◽  
Contrast Agent ◽  
Contrast Agent Bolus ◽  
Artery Geometry

scholarly journals Use of the mean transit time of an intravascular contrast agent as an exchange-insensitive index of myocardial perfusion

1999 ◽  
Vol 9 (3) ◽  
pp. 402-408 ◽  
Author(s):  
Massimo Lombardi ◽  
Richard A. Jones ◽  
J�rgen Westby ◽  
Geir Torheim ◽  
Timothy E. Southon ◽  
...  
Keyword(s):  
Myocardial Perfusion ◽  
Contrast Agent ◽  
Transit Time ◽  
Mean Transit Time ◽  
Intravascular Contrast Agent ◽  
The Mean

scholarly journals Dynamic contrast-enhanced QSM for perfusion imaging: a systematic comparison of ΔR2*- and QSM-based contrast agent concentration time curves in blood and tissue

2020 ◽  
Vol 33 (5) ◽  
pp. 663-676
Author(s):  
Emelie Lind ◽  
Linda Knutsson ◽  
Freddy Ståhlberg ◽  
Ronnie Wirestam
Keyword(s):  
Contrast Agent ◽  
Arterial Input Function ◽  
Tissue Concentration ◽  
Input Function ◽  
Dynamic Susceptibility ◽  
Dynamic Susceptibility Contrast ◽  
Concentration Data ◽  
Concentration Time ◽  
Dynamic Susceptibility Contrast Mri ◽  
Dsc Mri

Abstract Objective In dynamic susceptibility contrast MRI (DSC-MRI), an arterial input function (AIF) is required to quantify perfusion. However, estimation of the concentration of contrast agent (CA) from magnitude MRI signal data is challenging. A reasonable alternative would be to quantify CA concentration using quantitative susceptibility mapping (QSM), as the CA alters the magnetic susceptibility in proportion to its concentration. Material and methods AIFs with reasonable appearance, selected on the basis of conventional criteria related to timing, shape, and peak concentration, were registered from both ΔR2* and QSM images and mutually compared by visual inspection. Both ΔR2*- and QSM-based AIFs were used for perfusion calculations based on tissue concentration data from ΔR2*as well as QSM images. Results AIFs based on ΔR2* and QSM data showed very similar shapes and the estimated cerebral blood flow values and mean transit times were similar. Analysis of corresponding ΔR2* versus QSM-based concentration estimates yielded a transverse relaxivity estimate of 89 s−1 mM−1, for voxels identified as useful AIF candidate in ΔR2* images according to the conventional criteria. Discussion Interestingly, arterial concentration time curves based on ΔR2* versus QSM data, for a standard DSC-MRI experiment, were generally very similar in shape, and the relaxivity obtained in voxels representing blood was similar to tissue relaxivity obtained in previous studies.

scholarly journals Reliable Estimation of Capillary Transit Time Distributions Using DSC-MRI

2014 ◽  
Vol 34 (9) ◽  
pp. 1511-1521 ◽  
Author(s):  
Kim Mouridsen ◽  
Mikkel Bo Hansen ◽  
Leif Østergaard ◽  
Sune Nørhøj Jespersen
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Transit Time ◽  
Neuronal Response ◽  
Mean Transit Time ◽  
Oxygen Extraction Fraction ◽  
Dynamic Susceptibility ◽  
Arterial Blood ◽  
Dsc Mri ◽  
Wide Range

The regional availability of oxygen in brain tissue is traditionally inferred from the magnitude of cerebral blood flow ( CBF) and the concentration of oxygen in arterial blood. Measurements of CBF are therefore widely used in the localization of neuronal response to stimulation and in the evaluation of patients suspected of acute ischemic stroke or flow-limiting carotid stenosis. It was recently demonstrated that capillary transit time heterogeneity ( CTH) limits maximum oxygen extraction fraction ( OEFmax) that can be achieved for a given CBF. Here we present a statistical approach for determining CTH, mean transit time ( MTT), and CBF using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Using numerical simulations, we demonstrate that CTH, MTT, and OEFmax can be estimated with low bias and variance across a wide range of microvascular flow patterns, even at modest signal-to-noise ratios. Mean transit time estimated by singular value decomposition (SVD) deconvolution, however, is confounded by CTH. The proposed technique readily identifies malperfused tissue in acute stroke patients and appears to highlight information not detected by the standard SVD technique. We speculate that this technique permits the non-invasive detection of tissue with impaired oxygen delivery in neurologic disorders such as acute ischemic stroke and Alzheimer's disease during routine diagnostic imaging.

Liver vascular transit time analyzed with dynamic hepatic venography with bolus injections of an US contrast agent: early experience in seven patients with metastases.

Radiology ◽  
1998 ◽  
Vol 209 (3) ◽  
pp. 862-866 ◽  
Author(s):  
M J Blomley ◽  
T Albrecht ◽  
D O Cosgrove ◽  
V Jayaram ◽  
R J Eckersley ◽  
...  
Keyword(s):  
Contrast Agent ◽  
Transit Time ◽  
Early Experience

scholarly journals Improved contrast agent bolus tracking using T1 FARM

1999 ◽  
Vol 41 (3) ◽  
pp. 429-435 ◽  
Author(s):  
C.A. McKenzie ◽  
R.S. Pereira ◽  
F.S. Prato ◽  
Z. Chen ◽  
D.J. Drost
Keyword(s):  
Contrast Agent ◽  
Bolus Tracking ◽  
Contrast Agent Bolus
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