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Comparing Arterial Input Function Measurements in DCE-MRI Using MOLLI and Phase
N Majtenyi1*, H Gabrani-Juma2, R Klein2, RA deKemp3, G Cron2, TB Nguyen2, I Cameron2, (1) Carleton University, Ottawa, Ontario, (2) The Ottawa Hospital, Ottawa, Ontario, (3) University of Ottawa Heart Institute, Ottawa, Ontario
Presentations
SU-G-IeP1-3 (Sunday, July 31, 2016) 4:00 PM - 4:30 PM Room: ePoster Theater
Purpose: To compare two different methods for measuring the arterial input function (AIF) in dynamic contrast-enhanced (DCE)-MRI.
Methods: Five DCE-MRI experiments were performed on an aqueous DCE-MRI phantom (Shelley Medical) in a Siemens 3T Trio MRI scanner with 32 channel head coil and clinical DCE-MRI protocol. MRI signal phase (φ) data were saved for offline processing. T1 relaxation measurements, using a Modified Look-Locker Inversion Recovery (MOLLI) pulse sequence, were performed pre- and post-DCE. The input flow rate was set to 200 mL/min to mimic blood flow in the human body. The AIF of Gd injection was determined with two different methods. 1. “Phase-only”: Pre-injection baseline phase (φ₀) was subtracted from phase-vs-time [φ(t)]. This quantity, φ(t) – φ₀, was then used to compute the AIF. 2. “Phase+MOLLI”: The AIF value during the post-injection steady-state washout, denoted AIF(w), was calculated from MOLLI T1s and known relaxivity. Phase during washout was denoted φ(w). The quantity φ(t) – φ(w) was used to compute AIF – AIF(w). The final Phase+MOLLI AIF was then calculated by adding the MOLLI AIF(w). A “gold-standard” AIF(w) was also obtained by sampling liquid in the input tube port of the phantom post-DCE, then later measuring T1 with standard inversion recovery (IR). AIF(w) values from Phase-only, MOLLI, and IR were compared using a two-tailed paired t-test.
Results: AIF(w) from Phase-only and MOLLI were significantly different (p = 0.04). AIF(w) from MOLLI and IR were the same (p = 0.89). The Phase-only curve therefore incorrectly estimated AIF(w).
Conclusion: There is currently no standard method for determining the AIF in DCE-MRI. This work has shown that a Phase-only AIF returns incorrect values for the washout portion of the curve. The Phase+MOLLI method could provide a more accurate and reproducible AIF in clinical DCE-MRI, which could lead to better diagnoses.
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