Phase-based arterial input functions in humans applied to dynamic contrast-enhanced MRI: potential usefulness and limitations

Abstract

Phase-based AIFs are a feasible alternative to magnitude AIFs, but sources of errors exist, making quantification difficult, especially of the AIF tail. Improvement of the technique is feasible and also required for the phase-based AIF approach to reach its full potential.

Comparison of the Diagnostic Accuracy of DSC- and Dynamic Contrast-Enhanced MRI in the Preoperative Grading of Astrocytomas

“…This limitation can be overcome by using phase images to derive the VIF. [9][10][11][12][13] Phase measurements are less biased by intensity changes from inflow and relaxation effects. Magnitude-derived vascular input functions can underestimate the contrast concentration measurement during the first pass (if Ͼ5 mmol/L), especially when a high-relaxivity agent is used.…”

“…7,8 Recently, some au-thors have suggested that measuring changes in the phase of the MR signal rather than its magnitude following gadolinium injection might provide a more accurate VIF because phase change inside the vessel is linearly related to the concentration of contrast agent. [9][10][11][12] While measurement of precontrast tissue T1 is typically included in DCE-MR imaging studies, an additional measurement of tissue T1 postinjection ("bookend" method) might also improve the reproducibility of perfusion values in gliomas. 13,14 To our knowledge, there have been few comparative studies between DCE and DSC imaging in patients with gliomas.…”

Dynamic susceptibility contrast perfusion MRI using phase-based venous output functions: comparison with pseudo-continuous arterial spin labelling and assessment of contrast agent concentration in large veins

“…An approximation to the CA concentration C in a large vessel can thus be obtained from the frequency shift or phase shift of the cylinder in combination with the molar susceptibility χ M,Gd of the gadolinium-based CA [e.g., 25,26]: For determination of the angle θ in this study, the slice orientation relative to B 0 was recorded, and the phase/frequency measurements were conducted with the vessel oriented perpendicular to the slice.…”

Estimating the arterial input function from dynamic contrast‐enhanced MRI data with compensation for flow enhancement (II): Applications in spine diagnostics and assessment of crohn's disease

“…Alternative methods that correct for flow include the reference region model AIF or the phase‐based AIF approach . Our method is different in that it specifically addresses the flow and saturation artifacts.…”