TY - JOUR
T1 - Contrast-agent phase effects
T2 - An experimental system for analysis of susceptibility, concentration, and bolus input function kinetics
AU - Akbudak, Erbil
AU - Norberg, Richard E.
AU - Conturo, Thomas E.
PY - 1997/12
Y1 - 1997/12
N2 - A system is presented for experimental arterial input function (AIF) simulation and for accurate measurement of the concentration, susceptibility effects, and magnetic moment of paramagnetic MR contrast agents. Signal effects of contrast agents are evaluated with a stable, well-characterized, and precise experimental setup. A cylindrical phantom and a closed-loop circulating flow system were designed for AIF simulation, assessment of the physical determinants of contrast-agent phase effects, and measurement of contrast-agent properties under controlled conditions. A mathematical model of the AIF dynamics is proposed. From the experimental phase shift (Δφ), either the concentration or molar susceptibility, X(M), is determined. The linear dependence of ΔΦ on concentration and echo time (TE), the orientation dependence, and the lack of dependence on T1, T2, and diffusion time are proven precisely for water solutions under a wide variety of conditions. The measured effective magnetic moment of Gd+3, μ(eff), was 7.924 ± 0.015 Bohr magnetons in agreement with the theoretical value of 7.937.
AB - A system is presented for experimental arterial input function (AIF) simulation and for accurate measurement of the concentration, susceptibility effects, and magnetic moment of paramagnetic MR contrast agents. Signal effects of contrast agents are evaluated with a stable, well-characterized, and precise experimental setup. A cylindrical phantom and a closed-loop circulating flow system were designed for AIF simulation, assessment of the physical determinants of contrast-agent phase effects, and measurement of contrast-agent properties under controlled conditions. A mathematical model of the AIF dynamics is proposed. From the experimental phase shift (Δφ), either the concentration or molar susceptibility, X(M), is determined. The linear dependence of ΔΦ on concentration and echo time (TE), the orientation dependence, and the lack of dependence on T1, T2, and diffusion time are proven precisely for water solutions under a wide variety of conditions. The measured effective magnetic moment of Gd+3, μ(eff), was 7.924 ± 0.015 Bohr magnetons in agreement with the theoretical value of 7.937.
KW - Contrast agents
KW - MRI
KW - Perfusion
KW - Susceptibility
UR - http://www.scopus.com/inward/record.url?scp=0030701922&partnerID=8YFLogxK
U2 - 10.1002/mrm.1910380619
DO - 10.1002/mrm.1910380619
M3 - Article
C2 - 9402201
AN - SCOPUS:0030701922
SN - 0740-3194
VL - 38
SP - 990
EP - 1002
JO - Magnetic resonance in medicine
JF - Magnetic resonance in medicine
IS - 6
ER -